{'fraction_non_alphanumeric': 0.03500258665287118, 'fraction_numerical': 0.029332643559234352, 'mean_word_length': 4.860833181735492, 'pattern_counts': {'":': 0, '<': 7, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 28, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Acute poisoning in Shenyang, China: a retrospective and descriptive study from 2012 to 2016

Objectives Up-to-date information on the patterns of acute poisoning is crucial for the proper management of poisoning events. The objectives of this study were to analyse the characteristics of patients suffering from acute poisoning admitted to the emergency department (ED) in a tertiary medical centre in Northeast China and to compare these characteristics with those of a previous comparable study. Design Retrospective and descriptive study. Setting Data were collected from the hospital information system in Shengjing Hospital, China, from January 2012 to December 2016. Participants All cases aged ≥11 years old with a diagnosis of acute poisoning. Results In total, 5009 patients aged ≥11 years presented to the ED with acute poisoning during the study period. The average age of the patients was 36.0±15.1 years and over half (52.7%) were in the 20–39age group. The female to male ratio was 1.2:1. Patients with acute poisoning mainly lived in rural areas rather than in urban areas. The majority of patients consumed poison as suicide attempts (56.7%). Men were more commonly poisoned by drug abuse than women, but women outnumbered men in suicidal poisoning. The most common form of poison intake was ingestion (oral intake; 86.2%). The five most common toxic agent groups, in descending order, were therapeutic drugs (32.6%), pesticides (26.9%), alcohol (20.7%), fumes/gases/vapours (11.4%) and chemicals (3.6%). Sedatives/hypnotics in the therapeutic drugs group and paraquat in the pesticides group were the most common toxic agents, respectively. The mortality rate of study participants was 1.3%, with 64 deaths. Conclusions The results of this study indicate the need to strengthen education on the rational and safe use of drugs in Shenyang.

Although the sample size for the study is large, retrospective nature makes it difficult to obtain the whole information of all poisoning cases, which brought into the bias.
Considering that some of mild and particularly serious poisoning cases fail to seek for medical help, outcomes of the study may differ from the actual fact.

Introduction
Acute poisoning is defined as acute exposure (less than 24 hrs) to the toxic substance. [1] Acute poisoning is a major public and preventable health issue contributing to morbidity and mortality in many parts of the world. It is estimated that poisoning events are responsible for more than one million illnesses annually. [2,3] Low mortality contrasts with high morbidity in acute poisoning; however, patients who attempt suicide usually have higher mortality. [4][5][6] As the most common form of fatal self-harm in rural Asia, poisoning accounts for more than 60% of deaths. [7] China is a developing country and is changing from an agricultural to an industrialized economy. In recent years, the number of acute poisoning cases in China has continued to increase [8], so that now poisoning and injury have entered the top five causes of death. [9] Of various type of poisonings, pesticide poisonings were more common in most regions of China while pharmaceutical poisonings were the main type of poisoning in the developed region or city, such as Shanghai. [9][10][11][12][13] Shengyang, is the provincial capital of Liaoning, the biggest city in Northeast China and the national regional central city, with estimated population more than 8.1million. Liaoning is an industrial province, but agriculture is still the important economic sector. The major crops in this region are corn and rice. The heavy use of pesticides such as organophosphorous compounds by farmers may increase the risk of poisoning events in this area. [14] A previous investigation in this region from 1997 to 2007 showed that (i) medicine was the most common agent (41.4%), followed by pesticides (15.2%), alcohol (14.1%), carbon monoxide (12.5%) and food (9.7%); (ii) the major medicine was sedative/hypnotic and the major pesticide was organophosphates; (iii) mortality decreased from 2.05% to 0.37% over the 10-year study period, with an average mortality rate of 1.0%. [15] In the last few decades, China has witnessed significant advancements in the fields of agriculture, industrial technologies and medical pharmacology. These advancements have been paralleled with remarkable changes in the trends of acute poisoning, [16] and led to the development and easy accessibility of a vast number of toxic agents including pesticides, therapeutic drugs and other chemicals. Thus, the toxic agents associated with morbidity and mortality and the pattern of acute poisoning, which vary from place to place and over time, are expected to change.
Therefore, there is a constant need to obtain up-to-date information on acute poisoning for planning rational use of resources and for evaluating public health interventions. The aim of this retrospective and descriptive study was to describe the clinical and sociodemographic patterns of acute poisoning in the medicine emergency department of Shengjing Hospital of China Medical University, a tertiary care center.

Methods
This retrospective and descriptive study based on hospital records was carried out in the Shengjing Hospital of China Medical University in Shenyang, China.
Shengjing hospital is one of the regional tertiary care hospitals in northeast China with 3 hospital areas, and covers the whole Liaoning province and some area of neighboring provinces. Moreover, Liaoning Poisoning Diagnosis and Treatment Center (PDTC) is established in ED of Shengjing hospital on July 2011, and ED owns specialized toxicology unit, hence many patients with poisoning who seek for treatment visit or are referred to this hospital. We reviewed all records of poisoning cases admitted to the ED over 5 consecutive years from January 2012 to December 2016. Cases of animal bites (snake, insect) for its infrequency and chronic poisoning were excluded from the study. Research ethical approval was obtained from Shengjing hospital institutional ethics committee before the study commence.
Relevant medical records were obtained from the electronic hospital information system (HIS). The HIS is an electronic system used in the clinic to record patient information. From HIS, patient information including personal information, present history, past history, diagnosis, treatment and prognosis can be obtained.
Demographic data including age, gender, place of residence, diagnosis, type of exposure (intentional or non-intentional), type of toxic agent (the common name or trade name are indicated, where available), duration of hospital stay and the outcome of treatment (whether the patient survived or died) were collected and documented on a structured form. The circumstance of poisoning was deduced from the patients' history. If patients were poisoned because of being in the environment where toxic substance (e.g.: CO) exist it was categorized as environmental poisoning. The overdoses of medicine or being given the wrong drug, taking the wrong drug in error, or taking a drug inadvertently were categorized as misuse. The side effect of herbs or health-products was categorized as adverse reaction. In addition, cases of suicide and drug abuse were classified as intentional poisoning. If information was unavailable it was categorized as unknown. Diagnosis was routinely made on the basis of the generic name of the toxic agent, i.e. organophosphate compounds. The toxic agent was categorized as unknown when no suspected toxic agent was reported in the patient history.
Microsoft Excel 2007 was used to perform descriptive statistical analyses of the data. The average age was presented as the mean ± standard deviation (SD). The rate was compared using the chi-square test and used as the inferential statistic.

Results
A total of 5,375 cases of poisoning (age ≥11 years of age) from 829,808 entries were obtained from the HIS from 1 January 2012 to 31 December 2016. Of these, 366 were identified as animal bites (10) and chronic poisoning events, leaving a total of 5009 unique cases that met our criteria. Descriptive information including age, gender, type and route of exposure, place of residence, length of hospital stay, and outcome of the poisoned patients are summarized in Table 1.    Table 3 shows the reasons for toxin exposure in these patients. It was noted that intentional exposure occurred in the overwhelming majority of poisonings (3947, 78.8%), followed by accidental exposure (1107, 20.3%), unknown reason (45, 0.9%).

Type for exposure
Intentional poisoning was mainly due to suicide (2842, 56.74%) followed by drug abuse such as alcohol and antitussive (1105, 22.06%).There was a significant association between intentional exposure (suicide versus abuse) and gender, where women were involved in more suicidal poisonings than men; 63.4% for women versus 35.2% for men (p < 0.001). Poisoning due to drug abuse showed the opposite trend; 70.7% for males versus 29.3% for females (p < 0.01). The most substances used were therapeutic drugs and pesticides for suicidal attempt and alcohol for abuse. CO poisoning (about 80% of cases) was the most common in environmental poisonings, and pesticides poisoning (20%) was less common. Therapeutic drugs were overdose or taken mistakenly by females.

Route of exposure
Among the various routes of exposure, ingestion was the most common (86.16 %), followed by inhalation (11.78%) and contact (1.96%).

Common Substances in Human Exposures
The most prevalent substance categories are shown in Table 4 and are listed by frequency of exposure in these patients. This ranking shows the direction where prevention efforts should be focused, as well as the types of poisonings our hospital regularly manages. It is crucial to know whether exposure to these toxic agents is increasing or decreasing. The overall trend of poisoning events was down. The four most common toxic agent group in decreasing order were therapeutic drugs, pesticides, alcohol, fumes/gases/vapors, 676 (13.47%) patients consumed two or more toxic agents. However, when it came to specific substance, alcohol, paraquat, CO and sedatives and hypnotics were the first four toxic agents.

3.4.1Therapeutic drug categories
The therapeutic drug poisoning showed a slight decreased trend across the consecutive five years in spite of a high number in 2013. A total of 1637 cases had therapeutic drug poisoning. Among these cases, 28.77% involved sedatives and hypnotics poisoning, which were the most commonly employed drugs, followed by analgesics (16.55%) and cold and cough preparations (9.96%). Mixed drug poisoning was found in approximately 16.43% of patients. The rate of psychotropics poisoning was increasing over the five years. Cardiovascular drugs, antimicrobials, traditional medicine and other drugs showed relatively stable trend. Drug poisoning was more common in both males and females aged 20-29 years with suicidal attempt ( Figure 3).

4.2 Pesticide categories
The pesticide poisoning presented a growing trend from 2012 to 2015 but decreased in 2016. A total of 1349 cases were observed to have pesticide poisoning.
Among these cases, the predominant pesticide poison taken was paraquat (47.74% of cases), followed by rodenticide (19.20%), organophosphate (17.20%) and other pesticides (11.86%). A slightly higher number of males (683 cases) than females (666 cases) had pesticide poisoning. There were two peaks on the distribution of age and gender in pesticide poisoning, one in 20-29 years old and another in 40-49 years old for both males and females ( Figure 4). Eighty-eight percentage of pesticide poisoning occurred with suicidal attempt, but males exposed 5% more accidental pesticide poisoning than females. Pesticide poisoning was most frequent during the month of July.

Alcohol and Fumes/gases/vapors
There was a stable trend in the alcohol poisoning. Males were predominant population in alcohol poisoning and were approximately 2.5 times more than females.
The 20-29 years old were exposed more to alcohol poisoning than any other age groups. ( Figure 5) In addition, less one percent of alcohol poisoning cases were found Among these cases, CO poisoning was the dominating toxic agent. Major age group exposed to CO poisoning was 20-39 years old and females' exposure was more common. Majority of poisoning events occurred in winter.

Treatment and Outcome
Gastric lavage, administration with activated charcoal, infusion and dieresis therapy, hemoperfusion were regulatory treatment for those poisonings through ingestion. Hemodialysis was performed depending on the situation. Special antidotes, naloxone for alcohol poisoning, Vitamin K1 and acetamide for rodenticide poisoning, were given when needed. All patients with organophosphorous poisoning were treated with atropine and pralidoxime. For those poisoning with no specific antidotes available, symptomatic treatment was administered. In addition, hyperbaric oxygen therapy for CO poisoning was performed for all cases.
A total of 4945 patients were discharged from the hospital, including 1416 cases with complete recovery, 3319 cases with relative recovery, and 274 cases that left out of hospital during treatment or transferred to other central hospital. The hospital mortality rate was 1.28% with 64 deaths including 36 females and 28 males. The fatality ratio was 1.33% for female patients and 1.22% for male patients. More than half of the fatality cases (n=33) occurred in 40-59 age groups. Sixty-eight percentages of dead cases were patients living in urban areas. 51cases of death were with intentional purpose and 11cases of death were accidental, and in two cases, the type of poisoning was unknown. The associated agent involved in mortality was paraquat (33 cases), therapeutic drugs (16 cases), organophosphate (6 cases), food poisoning (4 cases), CO poisoning (2 cases), alcohol (1case) and two cases with unidentified poisons.

Discussion
Acute poisoning is one of the most frequent causes of visits to the ED and is a threat to public health. The annual rate of ED visits associated with poisoning varies widely across the world, and ranges from 0.07% to 0.7%. [17,18] Studies in western countries have reported annual rates of ED visits associated with poisoning of approximately 0.26%. [18,19] In the present study, this rate was about 0.65%, and a similar percentage (0.64%) was seen in Bulent' research. [20] As it is not common practice for many poisoned patients to seek medical help in health care institutions, the annual rate of ED visits associated with poisoning recorded by hospitals may be misleading. Therefore, the actual number of poisoning cases may be more than that recorded, and the accurate statistical data for poisonings is not easy to estimate.
Developed countries also have similar problems in obtaining meaningful poisoning statistics even though they are equipped with advanced systems to collect population health data . [21] This study concluded that the incidence of poisoning in females was slightly higher than that in males, especially among young adults aged 20-29 years, with a female-to-male ratio of 1.18:1. Similar findings have also been reported in Beijing, China [22] (1.23:1) and Sari, Iran [16] (1.16:1). In contrast, male preponderance has been found in some other countries. [23,24] The most likely explanation for the high number of poisoning in women is that they are emotionally fragile, more susceptible to stress, which can lead to overreacting behaviors.
The findings of this study showed a difference in poisoning based on age and indicated that the most affected age group was the 20-29 group (30.82%) with a secondary peak in the 30-39 group (21.88%). Both intentional and accidental poisoning were common in males and females aged 20-29 years, which is consistent with previous findings in China [15,22] and in other countries [16,[25][26] . The fact that poisoning is more common among young adults reflects their vulnerability to stress, possibly due to failure or frustration in love or exams, maladjustment and inability to cope with the high expectation of parents. Overall, this group of people is not emotionally stable or mature enough to tolerate extreme mental or physical pressure.
Intentional poisoning was the predominant cause of poisoning(78.8%) in the current study, an observation that is consistent with those made in other studies. [25,27] Our study indicated of the whole of poisoning cases, a large proportion were suicidal in nature, which was decreased compared to previous study [15] . In spite of the decline in the suicidal rate, suicide attempt still is the primary reason for poisoning because of the general acknowledgment that poisons terminate life with minimal suffering. [28,29] We found a lot of suicidal behaviors were initiated after an acute interpersonal conflict.
It was consistent with a multivariate analysis about suicide reason in a research performed in China, which revealed that marriage frustration, work and learning problem, family fanaticism and conflict, somatic disease, and history of mental disorders were all significantly associated with suicide attempts. [30] Our study pointed out that pharmaceutical drugs were the most frequently employed toxic agents. Pharmaceutical poisoning comprised 32.6% of the various drug poisonings observed in the present study, of which sedatives and hypnotics (28.78%) were the most frequently ingested agents. Similar pattern was also seen in previous study, compared to which there appeared a decline in sedatives and hypnotics poisoning in our study [17] . This decline may be connected with the implementation of drug-control that patients can only access these drugs with a doctor's prescription. However, a rise were seen in usage of analgesics, cold and cough medicines, mixed drugs, as well as cardiovascular drugs, making it not the same as before. This may be explained by the easy availability of pharmaceuticals due to the numerous drugstores in China, poor psychological well-being and mental fragility among populations. Additionally, we found the frequency of psychotropic drugs poisonings were growing, which indicated that mental disorder played a part in poisoning events and should be gave attention.
Poisoning with pesticide products has been occurring relatively frequently for some time, as can be observed in published papers from different countries. [ industry, and home storage causing toxicity due to intentional and accidental exposure. [33] The quantity of pesticide use is large and ever-increasing, growing from 1.28million ton in 2001 to 1.81 million ton in 2014 [34] . Liaoning, as a major agriculture province, bears a mount of proportion of pesticide consumption to protect crops and increase food production [35] . Owing to the respective nature, we didn't get the detailed information about the use and storage of pesticides in patients' home.
However, we found about twelve percent of pesticide poisoning were accidental, of which males exposed 5% more accidental pesticide poisoning than females, and almost all these cases occurred when they were working in the fields. This indirectly indicates the influence of unreasonable use and poor self-protection on poisoning. In the present study, paraquat was the most frequently implicated agent among the pesticides, and a similar pattern was found in a study in northeast China which showed an increasing trend [36] , whereas a decreasing trend was found in Korea [37] .
Compared to the previous pattern, the most common pesticide products have changed from organophosphates to paraquat. Organophosphates have fallen behind the rodenticide to the third place. Studies carried out in other parts of China showed that organophosphates were the most frequently used pesticides [11] . This imparity is related to difference of the social-economic and geographical conditions. Previous studies have revealed that season-specific agricultural activities contribute to the change in the incidence of pesticide poisoning throughout the year, and the high incidence of pesticide poisoning is related to the easy accessibility of pesticides during the farming season. [38] Our results indicated that pesticide poisoning, both intentional and accidental, was common in June and in July, during the farming season in Liaoning, with 181 cases and 208 cases, respectively, but was less common in winter.
Not surprisingly, our study found that alcohol poisoning was common and found in 20.7% of our cases. This value was increased compared to the before. This change can be explained by rapid social and economic development, urbanization, increasing alcohol production, and alcoholic beverage commercials in the mass media, which all led to the growing alcohol consumption. [39] According to a set of data the annual per-capita alcohol consumption of Chinese adults in 2012 was 3 liters. [40] Some findings reported elsewhere in China had higher number of alcohol poisonings. [41] Whereas the value in studies that involved the alcohol poisoning in other countries showed a lower proportion [42][43][44][45] . This kind of discrepancy is partially related to the disparity in alcohol consumption habits between different countries and districts.
In Chinese culture, people often urge companions to drink as much as possible so that they can construct social connections and establish a happy and congenial atmosphere. [46] This can also explain the gender difference as men are more engaged in social intercourse than women. Except for wildly practiced social drinking, solitary drinking was also common for stress reduction and coping among Chinese. [47] The current data showed that the fourth leading cause of acute poisoning was fumes/gases/vapors (mainly CO), decreasing from 12.5% to less than 11.4% in spite of remaining in fourth place. This reduction is related to the improvement of dwelling conditions and preventive education about CO poisoning. With the improvement of heating measures and the advancing of the fuel switching project from coal to natural gas in rural areas, further decline in CO poisoning is expected in rural areas in China.
There was a significant association between residency and month and reason for exposure to CO. Rural residents are more susceptible to CO poisoning than urban citizens, as local residents in remote villages in northern China use stoves to keep warm in winter, which can result in gas leaks due to a chimney jam and lack of ventilation, and are common causes of CO poisoning in these areas. In contrast, CO poisoning in urban citizens may be explained by eating barbecued food and hotpot, a very famous traditional Chinese cuisine; both require charcoal as fuel. In addition, almost all CO poisoning cases in our study were accidental with the exception of one case which was a suicide. The present data provide additional insight into the epidemiology of acute poisoning in Shenyang. The findings demonstrated that more females than males had acute poisoning and the most vulnerable age group was the young-adult group aged 20-29. We also observed that the majority of poisoning cases were intentional, particularly suicidal in nature, and accidental poisonings were nonnegligible. Our study indicated that therapeutic drugs were the most commonly used toxic agent group, followed by pesticides, alcohol and noxious gas. Additionally, alcohol was the first substance that caused most single substance poisoning. In conclusion, the pattern of acute poisoning in Shenyang altered significantly compared to that of ten years ago.

Conclusion and Suggestions
Some suggestions are proposed based on the present study and include the following: Vulnerable groups such as females, young-adult group should deserve special consideration for their weak bearing capacity.
Further investment is required to promote public health education on the rational use and safe storage of toxic agents as well as self-protection to reduce accidental poisoning.
The agenda of addressing the upward trend of prevalence and alcohol and drug use should capture increasing attention.
Patients who attempt suicide must undergo psychiatric consultation as soon as possible. Early psychiatric consultation and identification may minimize the risk of further self-harm in suicidal cases.

Conclusions:
The results of this study indicate a need for strengthening the education about and management of the rational and safe use of drugs in Shenyang.

Strengths and limitations of this study:
Cross-sectional and retrospective design involved with over 5,000 poisoning cases in 5 consecutive years.
Although the sample size for the study is large, retrospective nature makes it difficult to obtain the whole information of all poisoning cases, which brought into the bias.
Statistics of a single centre teaching hospital-based study, though with three branches, might not present reflection of the generalized and precise situation in this region.

Introduction
Acute poisoning is defined as acute exposure (less than 24 h) to the toxic substance. [1] Acute poisoning is a major public and preventable health issue contributing to morbidity and mortality in many parts of the world. It is estimated that poisoning events are responsible for more than one million illnesses annually. [2,3] Low mortality contrasts with high morbidity in acute poisoning; however, patients who attempt suicide usually have higher mortality. [4][5][6] As the most common form of fatal self-harm in rural Asia, poisoning accounts for more than 60% of deaths. [7] China is a developing country and is changing from an agricultural to an industrialized economy. In recent years, the number of acute poisoning cases in China has continued to increase [8] , so that now poisoning and injury have entered the top five causes of death. [9] Of various type of poisonings, pesticide poisonings were more common in most regions of China while therapeutic drugs poisonings were the main type of poisoning in the developed region or city, such as Shanghai. [9][10][11][12][13] Shenyang, is the provincial capital of Liaoning, the biggest city in Northeast China and the national regional central city, with estimated population more than 8.1million. [14] Liaoning is an industrial province, but agriculture is still the important economic sector. The major crops in this region are corn and rice. The heavy use of pesticides such as organophosphorous compounds by farmers may increase the risk of poisoning events in this area. [15] A previous investigation in this region from 1997 to 2007 showed that (i) medicine was the most common agent (41.40%), followed by pesticides (15.20%), alcohol (14.10%), carbon monoxide (12.50%) and food (9.70%); (ii) the major In the last few decades, China has witnessed significant advancements in the fields of agriculture, industrial technologies and medical pharmacology. These advancements have been paralleled with remarkable changes in the trends of acute poisoning, [17] and led to the development and easy accessibility of a vast number of toxic agents including pesticides, therapeutic drugs and other chemicals. Thus, the toxic agents associated with morbidity and mortality and the pattern of acute poisoning, which vary from place to place and over time, are expected to change. Type for exposure was classified as suicidal, abusive, accidental and unknown.
(1)An exposure due to the inappropriate use of drugs for self-destruction was categorized as suicidal.
(2)An exposure due to the intentional improper or incorrect use of a drug in which the victim was likely attempting to achieve a euphoric or psycho-tropic effect was categorized as abusive.

Age and gender
As shown, of these 5009 cases, 2713(54.20%) were recognized as female, and 2296 (45.80%) were determined as male, and the ratio of male to female was 1:1.18.
In this study, the youngest patient was 11 years old, while the oldest patient was 92   Table 3 shows the reasons for toxin exposure in these patients. It was noted that suicidal exposure occurred in the overwhelming majority of poisonings (2842, 56.74%), followed by abusive exposure (1105, 22.06%), accidental exposure (1017, 20.30%) and unknown reason (45, 0.90%). There was a significant gender difference in suicide and abuse: females were involved in more suicidal poisonings than males: 63.41% for females versus 36.59% for males (χ 2 =226.09, p <0.001); poisoning due to drug abuse showed the opposite status: 70.77% for males versus 29.23% for females (χ 2 =354.97, p<0.001). The most substances used were therapeutic drugs and pesticides for suicidal attempt and alcohol for abuse. CO poisoning (about 80% of cases) was the most common in environmental poisonings, and pesticides poisoning (20%) was less common. Therapeutic drugs were overdose or taken mistakenly by females.

Route of exposure
Among the various routes of exposure, ingestion was the most common (86.16 %), followed by inhalation (11.78%) and contact (1.96%).

Common Substances in Human Exposures
The most prevalent substance categories are shown in Table 4 and are listed by frequency of exposure in these patients. This ranking shows the direction where prevention efforts should be focused, as well as the types of poisonings our hospital regularly manages. The four most common toxic agent group in decreasing order were therapeutic drugs, pesticides, alcohol, fumes/gases/vapors, 676 (13.47%) patients consumed two or more toxic agents. However, when it came to specific substance, alcohol, paraquat, CO and sedatives and hypnotics were the first four toxic agents.

3.4.1Therapeutic drug categories
The therapeutic drug poisoning showed a slight decreased trend across the consecutive five years in spite of a high number in 2013. A total of 1637 cases had therapeutic drug poisoning. Among these cases, 28.77% involved sedatives and hypnotics poisoning, which were the most commonly employed drugs, followed by analgesics (16.55%) (including 13 cases of opioids poisoning) and cold and cough preparations (9.96%). Mixed drug poisoning was found in approximately 16.43% of patients. The rate of psychotropics poisoning was increasing over the five years.
Cardiovascular drugs, antimicrobials, traditional medicine and other drugs showed relatively stable trend. Drug poisoning was more common in both males and females aged 20-29 years with suicidal attempt ( Figure 3). However, drug poisoning was significantly more frequent in females than males (71.90% vs. 28.10%).

4.2 Pesticide categories
The pesticide poisoning presented a growing trend from 2012 to 2015 but decreased in 2016. A total of 1349 cases were observed to have pesticide poisoning.
Among these cases, the predominant pesticide poison taken was paraquat (47.74% of cases), followed by rodenticide (19.20%), organophosphate (17.20%) and other pesticides (11.86%). A slightly higher number of males (683 cases) than females (666 cases) had pesticide poisoning. There were two peaks on the distribution of age and gender in pesticide poisoning, one in 20-29 years old and another in 40-49 years old for both males and females ( Figure 4). Eighty-eight percentage of pesticide poisoning occurred with suicidal attempt, but males exposed 5% more accidental pesticide poisoning than females. Pesticide poisoning was most frequent during the month of July.

Alcohol and Fumes/gases/vapors
There was a stable trend in the alcohol poisoning. Males were predominant population in alcohol poisoning and were approximately 2.5 times more than females.
The 20-29 years old were exposed more to alcohol poisoning than any other age groups. ( Figure 5) In addition, less one percent of alcohol poisoning cases were found to be accompanied by other poisonings. Fumes/gases/vapors poisoning displayed an increasing trend as a whole even though there was a decrease from 2013 to 2014.
Among these cases, carbon monoxide poisoning was the dominating toxic agent.
Major age group exposed to CO poisoning was 20-39 years old and females' exposure was more common. Majority of CO poisoning events occurred in winter.

Treatment and Outcome
It was noted that gastric lavage and activated charcoal were respectively administrated in 72.54% (n=3634) cases and 64.76% (n=3244) cases to prevent absorption of toxic agents. 7.69% of cases (n=385) received hemodialysis treatment.
All patients with organophosphorous poisoning (n=232) were treated with atropine and pralidoxime. In addition, hyperbaric oxygen therapy for CO poisoning was performed for all cases (n=556).
A total of 4945 patients were discharged from the hospital, including 1416 cases with complete recovery, 3255 cases with relative recovery, 347 cases with referral to another institution, and 253 cases that left out of hospital during treatment. The hospital mortality rate was 1.28% with 64 deaths including 36 females and 28 males.
The fatality ratio was 1.33% for female patients and 1.22% for male patients. More than half of the fatality cases (n=33) occurred in 40-59 age groups. Sixty-eight percentages of dead cases were patients living in urban areas. 51cases of death were with suicidal attempt and 11cases of death were accidental, and in two cases, the type of poisoning was unknown. The associated agents involved in death were paraquat (33 cases), therapeutic drugs (16 cases), organophosphate (6 cases), food poisoning (4 cases), CO poisoning (2 cases), alcohol (1case) and two cases with unidentified poisons.

Comparison with Previous Findings
The female-to-male ratio was 1.5:1 in that study and 1.18:1in this study. Similar to the previous report; the most vulnerable patients were aged 20-29 years, but the 12.50% in that study and 32.62%, 26.88%, 20.71%, 11.40% in this study. The major medicine was sedative/hypnotic (27.50%) and the major pesticide was organophosphates (8.00%) in that study. The major medicine was sedative/hypnotic (9.36%) and the major pesticide was paraquat(12.83%). An average mortality rate of 1.0% was found in that study and 1.28% in this study.

Discussion
Acute poisoning is one of the most frequent causes of visits to the ED and is a threat to public health. The annual rate of ED visits associated with poisoning varies widely across the world, and ranges from 0.07% to 0.7%. [18,19] Studies in western countries have reported annual rates of ED visits associated with poisoning of approximately 0.26%. [19,20] In the present study, this rate was about 0.60%, and a similar percentage (0.64%) was seen in Bulent' research. [21] As it is not common practice for many poisoned patients to seek medical help in health care institutions, the annual rate of ED visits associated with poisoning recorded by hospitals may be misleading. Therefore, the actual number of poisoning cases may be more than that recorded, and the accurate statistical data for poisonings is not easy to estimate.
Developed countries also have similar problems in obtaining meaningful poisoning statistics even though they are equipped with advanced systems to collect population health data . [22] This study concluded that the incidence of poisoning in females was slightly higher than that in males, especially among young adults aged 20-29 years, with a female-to-male ratio of 1 found in some other countries. [24,25] The most likely explanation for the high number of poisoning in females is that they are emotionally fragile, more susceptible to stress, which can lead to overreacting behaviors. [26][27][28] The findings of this study showed a difference in poisoning based on age and indicated that the most affected age group was the 20-29 age-group (30.82%) with a secondary peak in the 30-39 age-group (21.88%). Both intentional and accidental poisoning were common in males and females aged 20-29 years, which is consistent with previous findings in China [16,23] and in other countries [29][30][31] . The fact that poisoning is more common among young adults reflects their vulnerability to stress, possibly due to failure or frustration in love or exams, maladjustment and inability to cope with the high expectation of parents. [32,33] Overall, this group of people is not emotionally stable or mature enough to tolerate extreme mental or physical pressure. [34,35] Intentional poisoning (suicide+abuse) was the predominant cause of poisoning(78.8%) in the current study, an observation that is consistent with those made in other studies. [30,36] Our study indicated of the whole of poisoning cases, a large proportion were suicidal in nature, which was decreased compared to previous study. This change may be related to the benefit of socioeconomic achievement and prosperity, such as higher employment and more educational opportunities, which may have contributed to the reduction of suicide rates in China. [37] In spite of the decline in the suicidal rate, suicide attempt still is the primary reason for poisoning because of the general acknowledgment that poisons terminate life with minimal suffering. [38,39] .
Our study pointed out that therapeutic drugs were the most frequently employed toxic agents. The similar pattern that therapeutic drugs were the most common cause of acute poisoning was seen in developed and some developing parts and countries. [40][41][42][43][44][45] Regarding the subgroup of therapeutic drugs, sedatives/hypnotics were common in Taiwan, Hong Kong, Iran and Finland, while analgesics were reported to be the most frequently ingested drugs in Turkey and USA. Pharmaceutical poisoning comprised 32.6% of the various drug poisonings observed in the present study, of which sedatives and hypnotics (28.78%) were the most frequently ingested agents.
Similar pattern was also seen in previous study, compared to which there appeared a decline in sedatives and hypnotics poisoning in our study [16] . This decline may be connected with the implementation of drug classification control that patients can only access these drugs with a doctor's prescription. [46] However, a rise were seen in usage of analgesics, cold and cough medicines, mixed drugs, as well as cardiovascular drugs, making it not the same as before. This may be explained by the easy availability of pharmaceuticals due to the numerous drugstores in China, inadequate supervision of government, insufficient knowledge about rational use of analgesics [47] , increase of incidence of cardiovascular disease [48] , poor psychological well-being and mental fragility among populations. [49] Additionally, we found the frequency of psychotropic drugs poisonings were growing, which indicated that mental disorder played a part in poisoning events and should be gave attention.
Poisoning with pesticide products has been occurring relatively frequently for some time, as can be observed in published papers from different countries. [36,39] The incidence of this poisoning varies geographically and historically [50] . Several studies conducted in India, Sri Lanka and Bangladesh showed a pesticide-dominating poisoning pattern, and organophosphates were the most common pesticide. [51][52][53] Pesticide was the second leading cause of acute poisoning in this study, accounting for 26.57% of all poisoning cases, the frequency increasing a lot compared to the before. [16] There are two reasons: first, suicide by pesticide poisoning still remains a priority for suicide in China, although suicides related to pesticide poisoning in China have continuously declined from 2006 to 2013. [54] Previous studies have shown that highly lethal pesticides are a common method used for suicide in rural China. [55,56] Our study finding that as high as eighty-eight percents of pesticide poisoning occurred with suicidal attempt also confirmed that. Second, pesticides are used extensively and unsafely in agriculture, industry, and home storage causing toxicity due to intentional and accidental exposure. [56] The quantity of pesticide use is large and ever-increasing, growing from 1.28million ton in 2001 to 1.81 million ton in 2014 [57] . In the present study, paraquat was the most frequently implicated agent among the pesticides, and a similar pattern was found in a study in northeast China which showed an increasing trend [58] , whereas a decreasing trend was found in Korea [59] .
Not surprisingly, our study found that alcohol poisoning was common and found in 20.7% of our cases. This value was increased compared to the before. This change can be explained by rapid social and economic development, urbanization, increasing alcohol production, and alcoholic beverage commercials in the mass media, which all led to the growing alcohol consumption. [60] According to a set of data the annual per-capita alcohol consumption of Chinese adults in 2012 was 3 liters. [61] Some findings reported elsewhere in China had higher number of alcohol poisonings. [62] Whereas the value in studies that involved the alcohol poisoning in other countries showed a lower proportion [41,[63][64][65] . This kind of discrepancy is partially related to the disparity in alcohol consumption habits between different countries and districts.
In Chinese culture, people often urge companions to drink as much as possible so that they can construct social connections and establish a happy and congenial atmosphere. [66] This can also explain the gender difference as men are more engaged in social intercourse than females. Except for wildly practiced social drinking, solitary drinking was also common for stress reduction and coping among Chinese. [67] The current data showed that the fourth leading cause of acute poisoning was fumes/gases/vapors (mainly CO), decreasing from 12.5% to less than 11.4% in spite of remaining in fourth place. This reduction is related to the improvement of dwelling conditions and preventive education about CO poisoning. With the improvement of heating measures and the advancing of the fuel switching project from coal to natural gas in rural areas, further decline in CO poisoning is expected in rural areas in China.
There was a significant association between residency and month and reason for exposure to CO. Rural residents are more susceptible to CO poisoning than urban citizens, as local residents in remote villages in northern China use stoves to keep warm in winter, which can result in gas leaks due to a chimney jam and lack of ventilation, and are common causes of CO poisoning in these areas. In contrast, CO poisoning in urban citizens may be explained by eating barbecued food and hotpot, a well-known traditional Chinese cuisine; both require charcoal as fuel. [68] In addition, almost all CO poisoning cases in our study were accidental with the exception of one case which was a suicide.
In our study, the rate of patients staying in hospital for less than 48h is small compared with other studies, it was related to that patients with poisoning usually were asked to remain in the observing room (available in our ED) for 48h to 72h in consideration of complex doctor-patient environment in China.

Conclusion and Suggestions
The present data provide additional insight into the epidemiology of acute poisoning in Shenyang. The findings demonstrated that more females than males had acute poisoning and the most vulnerable age group was the young-adult group aged 20-29. We also observed that the majority of poisoning cases were intentional, particularly suicidal in nature, and accidental poisonings were nonnegligible. Our study indicated that therapeutic drugs were the most commonly used toxic agent group, followed by pesticides, alcohol and noxious gas. In addition, the pattern of acute poisoning was slightly altered when roughly compared to that of ten years ago.
Poisoning due to analgesics and cold and cough preparations overpast poisoning due to psychotropics in therapeutical drugs poisoning. Meanwhile, poisoning due to paraquat and rodenticide exceeded poisoning due to organophosphate in pesticide poisoning.
Some suggestions are proposed based on the present study and include the following: Vulnerable groups such as females, young-adult group should deserve special consideration for their weak bearing capacity. [37] Further investment is required to promote public health education on the rational use and safe storage of toxic agents as well as self-protection to reduce accidental poisoning. [7] The agenda of addressing the upward trend of prevalence and alcohol and drug use should capture increasing attention.
Patients who attempt suicide must undergo psychiatric consultation as soon as Lastly, relevant policies and regulations should be formulated and initiated immediately to restrict access to toxic agents, especially pesticide for its high toxicity. [70]

Limitations
Our study was primarily limited by its retrospective nature, which resulted in missing patient data. Another limitation was that statistics of a single centre teaching hospital-based study, though with three branches, might not present reflection of the generalized and precise situation in this region. Hence, a more extensive data collection and analysis from other general hospitals in the region can depict the regional poisoning pattern more accurately. In addition, the comparison between two studies was rough because of the absence of data standardization. Sedatives/hypnotics in the therapeutic drugs group and paraquat in pesticides group was the most common toxic agents, respectively. The hospital mortality rate was 1.3% with 64 deaths.

Conclusions:
The results of this study indicate the need to strengthen education regarding management of the rational and safe use of drugs in Shenyang.

Strengths and limitations of this study:
The cross-sectional and retrospective study design involved with over 5,000 poisoning cases in 5 consecutive years.
Although the sample size in this study is large, its retrospective nature makes it difficult to obtain complete information in all poisoning cases, which introduced bias.
Statistics of a single centre teaching hospital-based study, even with three branches, may not reflect the precise situation in this region.

Introduction
Acute poisoning is defined as acute exposure (less than 24 h) to the toxic substance.
[1] Acute poisoning is a major public and preventable health issue contributing to morbidity and mortality in many parts of the world. It is estimated that poisoning events are responsible for more than one million illnesses annually. [2,3] Low mortality contrasts with high morbidity in acute poisoning; however, patients who attempt suicide usually have higher mortality. [4][5][6] As the most common form of fatal self-harm in rural Asia, poisoning accounts for more than 60% of deaths. [7] China is a developing country transitioning from an agricultural to an industrialized economy. In recent years, the number of acute poisoning cases in China has continued to increase [8] , and both poisoning and injury are now two of the top five causes of death. Liaoning is an industrial province, but agriculture is still an important economic sector.
The major crops in this region are corn and rice. The widespread use of pesticides such as organophosphorous compounds by farmers may increase the risk of poisoning events in this area. [15] A previous investigation in this region from 1997 to 2007 showed that (i) medicine was the most common agent (41.4%), followed by pesticides In the last few decades, China has witnessed significant advancements in the fields of agriculture, industrial technologies and medical pharmacology. These center, and to compare these patterns with previous findings.

Methods
This retrospective and descriptive study based on hospital records was carried out in the Shengjing Hospital of China Medical University in Shenyang, China.
Shengjing Hospital is one of the regional tertiary care hospitals in northeast China

Age and gender
Of the 5009 cases included, 2713(54.2%) were recognized as female, and 2296  (Figure 1). There was a statistically significant gender difference (male and female) between the different age groups of poisoned patients (χ 2 =28.19, p<0.001).
The predominant group of toxic agents consumed by the 20-29 age group was therapeutic drugs (579 cases, 37.4% of poisonings in the 20-29 age group) ( Table 2).
Of these, sedatives/hypnotics (169 cases) plus analgesics (120 cases) accounted for over half. Alcohol and pesticides were ranked second and third, accounting for 27.7% and 19.6%, respectively. There was a statistically significant gender difference at suicide and drug abuse in the 20-29 age group (χ 2 =140.29, χ 2 =167.69, p < 0.001).

Route of exposure
Among the various routes of exposure, ingestion was the most common (86.2 %), followed by inhalation (11.8%) and contact (2.0%).

3.4.1Therapeutic drug categories
Therapeutic drug poisoning showed a slight decrease during the five-year study despite a high number in 2013. A total of 1637 cases had therapeutic drug poisoning.
Of these cases, 28.8% involved sedatives/hypnotics poisoning, which were the most commonly used drugs, followed by analgesics ( However, drug poisoning was significantly more frequent in females than males (71.9% vs. 28.1%).

4.2 Pesticide categories
Pesticide poisoning showed an increasing trend from 2012 to 2015 but decreased in 2016. A total of 1349 cases were observed to have pesticide poisoning. Of these cases, the predominant pesticide poison taken was paraquat (47.7% of cases), followed by rodenticide (19.2%), organophosphate (17.2%) and other pesticides (11.9%). A slightly higher number of males (683 cases) than females (666 cases) had pesticide poisoning. With regard to the distribution of age and gender in pesticide poisoning, there were two peaks, one in the 20-29 year old group and the other in the 40-49 year old group for both males and females ( Figure 4). Eighty-eight percent of pesticide poisoning occurred with suicide attempt, and males were involved in 5% more accidental pesticide poisonings than females. Pesticide poisoning was most frequent during the month of July.

Alcohol and Fumes/gases/vapors
There was a stable trend in alcohol poisoning. Alcohol poisoning was

Treatment and Outcome
It was noted that gastric lavage and activated charcoal were administrated in 72.5%

Comparison with Previous Findings
The female-to-male ratio was 1.5:1 in a previous study and 1.18:1 in the present study. Similar to the previous report; the most vulnerable patients were aged 20-29 years, but the percentages in the previous study was 37.1% which was higher than that in this study). The major medicine was sedatives/hypnotics (27.5%) and the major pesticide was organophosphates (8.0%) in the previous study. The major toxic agents were sedatives/hypnotics (9.4%) and the major pesticide was paraquat(12.8%) in this study. The average mortality rate was 1.0% and 1.3%, respectively.

Discussion
Acute poisoning is one of the most frequent causes of visits to the ED and is a threat to public health. The annual rate of ED visits associated with poisoning varies widely across the world, and ranges from 0.07% to 0.7%. [18,19] Studies in western countries have reported annual rates of ED visits associated with poisoning of approximately 0.26%. [19,20] In the present study, this rate was 0.60%, and a similar percentage (0.64%) was seen in the research carried out by Bulent. [21] As it is not common practice for many poisoned patients to seek medical help in health care institutions, the annual rate of ED visits associated with poisoning recorded by hospitals may be misleading. Therefore, the actual number of poisoning cases may be more than that recorded, and accurate statistical data for poisonings are difficult to estimate. Developed countries also have similar problems in obtaining meaningful poisoning statistics even though they are equipped with advanced systems to collect population health data . [22] This study concluded that the incidence of poisoning in females was slightly higher than that in males, especially among young adults aged 20-29 years, with a female-to-male ratio of 1 of poisonings in females is that they may be more susceptible to stress, which can lead to overreactions. [26][27][28] The findings of this study showed a difference in poisoning based on age and indicated that the most affected age group was the 20-29 year age group (30.8%) with a secondary peak in the 30-39 year old group (21.9%). Both intentional and accidental poisoning were common in males and females aged 20-29 years, which is consistent with previous findings in China [16,23] and in other countries [29][30][31] . The fact that poisoning is more common among young adults reflects their vulnerability to stress, possibly due to failure or frustration in love or exams, maladjustment and inability to cope with the high expectation of parents. [32,33] Overall, this group of people is not emotionally stable or mature enough to tolerate extreme mental or physical pressure. [34,35] Intentional poisoning (suicide+abuse) was the predominant cause of poisoning(78.8%) in the current study, an observation that is consistent with that in other studies. [30,36] Our study indicated that of all poisoning cases, a large proportion were suicidal in nature, but the incidence was lowered compared with the previous study. This change may be related to the benefits of socioeconomic achievement and prosperity, such as higher employment and more educational opportunities, which may have contributed to the reduction in suicide rates in China. [37] Despite this decline in suicide rate, suicide attempt is still the primary reason for poisoning due to the general belief that poisons terminate life with minimal suffering. [38,39] .
Our study demonstrated that therapeutic drugs were the most frequently used toxic agents. A similar pattern that therapeutic drugs being the most common cause of acute poisoning has been observed in developed and some developing countries. [40][41][42][43][44][45] With regard to the subgroup of therapeutic drugs in poisoning cases, sedatives/hypnotics were common in Taiwan, Hong Kong, Iran and Finland, while analgesics were the most frequently ingested drugs in Turkey and USA.
Pharmaceutical poisoning comprised 32.6% of the various drug poisonings observed in the present study, of which sedatives/hypnotics (28.8%) were the most frequently ingested agents. A similar pattern was also seen in the previous study, although an apparent decline in sedatives/hypnotics poisoning was seen in our study [16] . This decline may be connected with the implementation of drug classification control where patients can only access these drugs with a doctor's prescription. [46] However, a rise was observed in the use of analgesics, cold and cough medicines, mixed drugs, as well as cardiovascular drugs, resulting in a different pattern to that seen previously.
This may be explained by the easy availability of pharmaceuticals due to the numerous drugstores in China, inadequate supervision of government, insufficient knowledge about rational use of analgesics [47] , increase of incidence of cardiovascular disease [48] , poor psychological well-being and mental fragility among populations. [49] In addition, we found the frequency of psychotropic drugs poisonings had increased, Previous studies have shown that highly lethal pesticides are commonly used in suicide in rural China. [57,58] Our study showed that up to 88% of pesticide poisonings were suicide attempts. Second, pesticides are used extensively and unsafely in agriculture, industry, and home storage causing toxicity due to intentional and accidental exposure. [58] The quantity of pesticide use is large and ever-increasing, and has grown from 1.28 million ton in 2001 to 1.81 million ton in 2014 [59] . In the present study, paraquat was the most frequently used pesticide, and a similar pattern was found in a study carried out in northeast China which showed an increasing trend [60] , whereas a decreasing trend was found in Korea [61] .
Not surprisingly, our study found that alcohol poisoning was common and accounted for 20.7% of all poisoning cases. The incidence of alcohol poisoning increased compared to previous figures. This change can be explained by rapid social and economic development, urbanization, increased alcohol production, and alcoholic beverage commercials in the mass media, which have all led to an increase in alcohol consumption. [62] According to recent data, the annual per-capita alcohol consumption in Chinese adults in 2012 was 3 L. [63] Findings reported elsewhere in China showed a higher number of alcohol poisonings. [64] Alcohol poisoning in other countries has been shown to be lower [41,[65][66][67] . This kind discrepancy is partially related to the disparity in alcohol consumption habits between different countries and districts.
In Chinese culture, people often urge companions to drink as much as possible so that they can construct social connections and establish a happy and congenial atmosphere. [68] This can also explain the gender difference in poisonings, as males are more engaged in social intercourse than females. In addition to wildly practiced social drinking, solitary drinking is also common for stress reduction and coping among Chinese. [69] The current data showed that the fourth leading cause of acute poisoning was fumes/gases/vapors (mainly CO), which decreased from 12.5% to less than 11.4% despite remaining in fourth place. This reduction is related to the improvement in dwelling conditions and preventive education on CO poisoning. With improvements in heating measures and advances in the fuel switching project from coal to natural gas in rural areas, a further decline in CO poisoning is expected in rural areas in China.
There was a significant association between residency and month and reason for exposure to CO. Rural residents are more susceptible to CO poisoning than urban citizens, as local residents in remote villages in northern China use stoves to keep warm in winter, which can result in gas leaks due to a chimney jam and lack of In our study, the rate of patients staying in hospital for less than 48h is small compared with other studies. This was due to patients with poisoning usually being asked to remain in the observing room (available in our ED) for 48h to 72h in consideration of complex doctor-patient environment in China.
Our study was primarily limited by its retrospective nature, which resulted in missing patient data. Another limitation was that the statistics of a single centre teaching hospital-based study, even with three branches, may not reflect precise situation in this region. Hence, a more extensive data collection and analysis from other general hospitals in the region can depict the regional poisoning pattern more accurately. In addition, the comparison between two studies was rough because of the absence of data standardization.

Conclusion and Suggestions
The present data provide additional insight into the epidemiology of acute poisoning in Shenyang. The findings demonstrated that more females than males had acute poisoning and the most vulnerable age group was the young-adult group aged 20-29. We also observed that the majority of poisoning cases were intentional, particularly suicidal in nature, and accidental poisonings were non-negligible. Our study indicated that therapeutic drugs were the most commonly used toxic agent group, followed by pesticides, alcohol and noxious gas. In addition, the pattern of acute poisoning was slightly altered when compared with 10 years ago. Poisoning due to analgesics and cold and cough preparations was more frequent than poisoning due to psychotropics in the therapeutic drugs poisoning group. In addition, poisoning due to paraquat and rodenticide exceeded poisoning due to organophosphate in the pesticide poisoning group. Some suggestions are proposed based on the present study and include the following: Vulnerable groups such as females and young adults deserve special consideration due to their weak coping capacity. [37] Further investment is required to promote public health education on the rational use and safe storage of toxic agents as well as self-protection to reduce accidental poisoning. [7] The upward trend in the prevalence and alcohol and drug use should receive increasing attention.
Patients who attempt suicide must undergo psychiatric consultation as soon as    Sedatives/hypnotics in the therapeutic drugs group and paraquat in the pesticides group were the most common toxic agents, respectively. The hospital mortality rate was 1.3% with 64 deaths.

Conclusions:
The results of this study indicate the need to strengthen education regarding management of the rational and safe use of drugs in Shenyang.

Strengths and limitations of this study:
The cross-sectional and retrospective study design included over 5,000 poisoning cases in 5 consecutive years.
Although the sample size in this study is large, its retrospective nature makes it difficult to obtain complete information in all poisoning cases, which introduced bias.
Data from a single centre teaching hospital-based study, even with three branches, may not reflect the precise situation in this region.

Introduction
Acute poisoning is defined as acute exposure (less than 24 h) to the toxic substance. [1] Acute poisoning is a major public and preventable health issue contributing to morbidity and mortality in many parts of the world. It is estimated that poisoning events are responsible for more than one million illnesses annually. [2,3] Low mortality contrasts with high morbidity in acute poisoning; however, patients who attempt suicide usually have higher mortality. [4][5][6] As the most common form of fatal self-harm in rural Asia, poisoning accounts for more than 60% of deaths. [7] China is a developing country transitioning from an agricultural to an industrialized economy. In recent years, the number of acute poisoning cases in China has continued to increase, [8] and both poisoning and injury are now two of the top five causes of death. [9] Of the various types of poisoning, pesticide poisoning is more common in most regions of China, while therapeutic drugs poisoning is the main type of poisoning in developed regions or cities, such as Shanghai. Liaoning is an industrial province, but agriculture is still an important economic sector.
The major crops in this region are corn and rice. The widespread use of pesticides such as organophosphorous compounds by farmers may increase the risk of poisoning events in this area. [15] A previous investigation in this region from 1997 to 2007 showed that (i) medicine was the most common agent (41.4%), followed by pesticides In the last few decades, China has witnessed significant advancements in the fields of agriculture, industrial technologies and medical pharmacology. These advancements have been paralleled by marked changes in the trends of acute poisoning, [17] and has led to the development and easy accessibility of a vast number of toxic agents including pesticides, therapeutic drugs and other chemicals. Thus, the toxic agents associated with morbidity and mortality and the pattern of acute poisoning, which vary from place to place and over time, are expected to change.
Therefore, there is a constant need to obtain up-to-date information on acute poisoning for planning rational use of resources and for evaluating public health interventions. The aim of this retrospective and descriptive study was to describe the clinical and sociodemographic patterns of acute poisoning in the medicine emergency department (ED) of Shengjing Hospital of China Medical University, a tertiary care center, and to compare these patterns with previous findings.

Methods
This retrospective and descriptive study based on hospital records was carried out in the Shengjing Hospital of China Medical University in Shenyang, China.
Shengjing Hospital is one of the regional tertiary care hospitals in northeast China with three hospital areas, and covers the entire Liaoning province and some areas of  The toxic agent was classified as a therapeutic drug, pesticide, alcohol, poisonous fume/gas/vapor, chemical, food, other substance and unknown. The subgroup of toxic agents was categorized based on the indications for use. Mixed drugs were defined as the ingestion of two or more drugs. The toxic agent was categorized as unknown when no suspected toxic agent was reported in the patient history.
Type of exposure was classified as suicidal, abusive, accidental and unknown as follows: (1) Exposure due to the inappropriate use of drugs for self-destruction was categorized as suicidal.
(2) Exposure due to the intentional improper or incorrect use of a drug in which the victim was likely attempting to achieve a euphoric or psycho-tropic effect was categorized as abusive. (3) Accidental was classified as environmental poisoning, misuse, food poisoning and an adverse reaction. ○ 1 If patients were poisoned due to being in an environment where a toxic substance (e.g.  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59  60   F  o  r  p  e  e  r  r  e  v  i  e  w  o  n  l  y   6 CO) was present this was categorized as environmental poisoning. ○ 2 An overdose of medicine or being given the wrong drug, taking the wrong drug in error, or taking a drug inadvertently were categorized as misuse. ○ 3 Exposure due to the ingestion of edible items was categorized as food poisoning. ○ 4 The side effect of an herb or health product was categorized as an adverse reaction. (4) If information was unavailable the cause of poisoning was categorized as unknown.
Gastric lavage, activated charcoal, intubation, infusion and dieresis therapy, and hemoperfusion were standard treatment protocols for poisonings caused by ingestion.
Hemodialysis was performed when indicated. Special antidotes, naloxone for alcohol poisoning, Vitamin K1 and acetamide for rodenticide poisoning, were given as indicated. For poisoning with no specific available antidotes, symptomatic treatment was administered.
Patients with normal symptoms, signs and laboratory findings on discharge were categorized as recovery. Patients with normal symptoms and signs but the laboratory findings were abnormal or unavailable on discharge were categorized as relative recovery.
Microsoft Excel 2007 was used to perform descriptive statistical analyses of the data. The average age was presented as the mean ± standard deviation (SD). To evaluate the differences, the chi-square test was performed using SPSS for Windows, version 21.0. A p value of less than 0.05 was considered significant.
Patient and Public Involvement: patients and/or the public were not involved.

Age and gender
The predominant group of toxic agents consumed by the 20-29 age group was therapeutic drugs (579 cases, 37.4% of poisonings in the 20-29 age group) ( Table 2).
Of these, sedatives/hypnotics (169 cases) plus analgesics (120 cases) accounted for over half. Alcohol and pesticides were ranked second and third, accounting for 27.7% and 19.6%, respectively. There was a statistically significant gender difference related to suicide and drug abuse in the 20-29 age group (χ 2 =140.29, χ 2 =167.69, p < 0.001).

Route of exposure
Among the various routes of exposure, ingestion was the most common (86.2 %), followed by inhalation (11.8%) and contact (2.0%).

3.4.1Therapeutic drug categories
Therapeutic drug poisoning showed a slight decrease during the five-year study despite a high number in 2013. A total of 1637 cases had therapeutic drug poisoning.
Of these cases, 28.8% involved sedatives/hypnotics poisoning, which were the most commonly used drugs, followed by analgesics ( However, drug poisoning was significantly more frequent in females than males (71.9% vs. 28.1%).

4.2 Pesticide categories
Pesticide poisoning showed an increasing trend from 2012 to 2015 but decreased in 2016. A total of 1349 cases were observed to have pesticide poisoning. Of these cases, the predominant pesticide poison taken was paraquat (47.7% of cases), followed by rodenticide (19.2%), organophosphate (17.2%) and other pesticides (11.9%). A slightly higher number of males (683 cases) than females (666 cases) had pesticide poisoning. With regard to the distribution of age and gender in pesticide poisoning, there were two peaks, one in the 20-29 year old group and the other in the 40-49 year old group for both males and females (Figure 4). Eighty-eight percent of pesticide poisonings were with suicide attempts, and males were involved in 5% more accidental pesticide poisonings than females. Pesticide poisoning was most frequent during the month of July.

Treatment and Outcome
It was noted that gastric lavage and activated charcoal were administered in 72.5% (n=3634) cases and 64.8% (n=3244) cases, respectively, to prevent absorption of toxic agents. Some 7.7% of cases (n=385) received hemodialysis treatment. All patients with organophosphorous poisoning (n=232) were treated with atropine and pralidoxime. In addition, hyperbaric oxygen therapy for CO poisoning was performed in all cases (n=556).
A total of 4945 patients were discharged from the hospital, including 1416 cases with complete recovery, 3255 cases with relative recovery, 347 cases were referred to another institution, and 253 cases left hospital during treatment. The hospital mortality rate was 1.3% with 64 deaths including 36 females and 28 males. The fatality ratio was 1.3% for female patients and 1.2% for male patients. More than half of the fatality cases (n=33) occurred in the 40-59 age group. Sixty-eight percent of the patients who died lived in urban areas. Death was due to suicide attempt in 51 cases, accidental poisoning in 11 cases, and in two cases, the type of poisoning was unknown. The associated agents involved in death were paraquat (33 cases), therapeutic drugs (16 cases), organophosphate (6 cases), food poisoning (4 cases), CO poisoning (2 cases), alcohol (1 case) and two cases with unidentified poisons.

Comparison with Previous Findings
The female-to-male ratio was 1.5:1 in a previous study and 1 in this study). The major medicine was sedatives/hypnotics (27.5%) and the major pesticide was organophosphates (8.0%) in the previous study. The major toxic agents were sedatives/hypnotics (9.4%) and the major pesticide was paraquat (12.8%) in this study. The average mortality rate was 1.0% and 1.3%, respectively.

Discussion
Acute poisoning is one of the most frequent causes of visits to the ED and is a threat to public health. The annual rate of ED visits associated with poisoning varies widely across the world, and ranges from 0.07% to 0.7%. [18,19] Studies in western countries have reported annual rates of ED visits associated with poisoning of approximately 0.26%. [19,20] In the present study, this rate was 0.60%, and a similar percentage (0.64%) was seen in the research carried out by Bulent. [21] As it is not common practice for many poisoned patients to seek medical help in health care institutions, the annual rate of ED visits associated with poisoning recorded by hospitals may be misleading. Therefore, the actual number of poisoning cases may be more than that recorded, and accurate statistical data for poisonings are difficult to estimate. Developed countries also have similar problems in obtaining meaningful poisoning statistics even though they are equipped with advanced systems to collect population health data. [22] This study concluded that the incidence of poisoning in females was slightly higher than that in males, especially among young adults aged 20-29 years, with a female-to-male ratio of 1.18:1. Similar findings have also been reported in Beijing, China [23] (1.23:1) and Sari, Iran [17] (1.16:1). In contrast, male preponderance has been found in some other countries. [24,25] The possible explanation for the high number of poisonings in females is that they may suffer a higher level of stress and depressive symptoms when compared to males, which can lead to overreactions. [26][27][28] The results of this study showed a difference in poisoning based on age and indicated that the most affected age group was the 20-29 year age group (30.8%) with a secondary peak in the 30-39 year old group (21.9%). Both intentional and accidental poisoning were common in males and females aged 20-29 years, which is consistent with previous findings in China [16,23] and in other countries [29][30][31] . The fact that poisoning is more common among young adults reflects their vulnerability to stress, possibly due to failure or frustration in love or exams, maladjustment and inability to cope with the high expectation of parents. [32,33] Overall, this group of people is not emotionally stable or mature enough to tolerate extreme mental or physical pressure. [34,35] Intentional poisoning (suicide+abuse) was the predominant cause of poisoning (78.8%) in the current study, an observation that is consistent with that in other studies. [30,36] Our study indicated that of all poisoning cases, a large proportion were suicidal in nature, but the incidence was lower compared with the previous study. This change may be related to the benefits of socioeconomic achievement and prosperity, such as higher employment and more educational opportunities, which may have contributed to the reduction in suicide rates in China. [37] Despite this decline in suicide rate, suicide attempt is still the primary reason for poisoning due to the general belief that poisons terminate life with minimal suffering. [38,39] .
Our study demonstrated that therapeutic drugs were the most frequently used toxic agents. A similar pattern of therapeutic drugs as the most common cause of acute poisoning has been observed in developed and some developing countries. [40][41][42][43][44][45] With regard to the subgroup of therapeutic drugs in poisoning cases, sedatives/hypnotics were common in Taiwan apparent decline in sedatives/hypnotics poisoning was seen in our study. [16] This decline may be connected with the implementation of drug classification control where patients can only access these drugs with a doctor's prescription. [46] However, a rise was observed in the use of analgesics, cold and cough medicines, mixed drugs, as well as cardiovascular drugs, resulting in a different pattern to that seen previously.
This may be explained by the easy availability of pharmaceuticals due to the numerous drugstores in China, inadequate supervision of government, insufficient knowledge about rational use of analgesics, [47] increase in the incidence of cardiovascular disease, [48] poor psychological well-being and mental fragility among populations. [49] In addition, we found that the frequency of psychotropic drugs poisonings had increased, which indicated that mental disorder played a part in poisoning events and should receive attention. It is noteworthy that the number of opioid poisonings is surprisingly small in our study, and this is associated with government's strict regulation on opiods, insufficient knowledge on opioids in physicians and patients (such as excessive worry about addiction and adverse events), making the use of opiods not-ubiquitous. [50,51] Pesticide poisoning has occurred relatively frequently for some time, as shown by previously published papers from different countries. [36,39] [59] In the present study, paraquat was the most frequently used pesticide, and a similar pattern was found in a study carried out in northeast China which showed an increasing trend, [60] whereas a decreasing trend was found in Korea. [61] Not surprisingly, our study found that alcohol poisoning was common and accounted for 20.7% of all poisoning cases. The incidence of alcohol poisoning increased compared to previous figures. This change can be explained by rapid social and economic development, urbanization, increased alcohol production, and alcoholic beverage commercials in the mass media, which have all led to an increase in alcohol consumption. [62] According to recent data, the annual per-capita alcohol consumption in Chinese adults in 2012 was 3 L. [63] Findings reported elsewhere in China showed a higher number of alcohol poisonings. [64] Alcohol poisoning in other countries has been shown to be lower. [41,[65][66][67] This discrepancy is partially related to the disparity in alcohol consumption habits between different countries and districts. In Chinese culture, people often urge companions to drink as much as possible so that they can construct social connections and establish a happy and congenial atmosphere. [68] This can also explain the gender difference in poisonings, as males are more engaged in social intercourse than females. In addition to widely practiced social drinking, solitary drinking is also common for stress reduction and coping among Chinese. [69] The current data showed that the fourth leading cause of acute poisoning was fumes/gases/vapors (mainly CO), which decreased from 12.5% to less than 11.4% despite remaining in fourth place. This reduction is related to the improvement in dwelling conditions and preventive education on CO poisoning. With improvements in heating measures and advances in the fuel switching project from coal to natural gas in rural areas, a further decline in CO poisoning is expected in rural areas in China.
There was a significant association between residency and month and reason for exposure to CO. Rural residents are more susceptible to CO poisoning than urban citizens, as local residents in remote villages in northern China use stoves to keep warm in winter, which can result in gas leaks due to a chimney jam and lack of ventilation, and are common causes of CO poisoning in these areas. In contrast, CO In addition, almost all CO poisoning cases in our study were accidental with the exception of one case which was a suicide.
In our study, the rate of patients staying in hospital for less than 48 h is small compared with other studies. This was due to patients with poisoning usually being asked to remain in the observing room (available in our ED) for 48 h to 72 h in consideration of the complex doctor-patient environment in China.
Our study was primarily limited by its retrospective nature, which resulted in missing patient data. Another limitation was that the data from a single centre teaching hospital-based study, even with three branches, may not reflect the precise situation in this region. Hence, extensive data collection and analysis from other general hospitals in the region may depict the regional poisoning pattern more accurately. In addition, the comparison between two studies was rough du to the absence of data standardization.

Conclusion and Suggestions
The present data provide additional insight into the epidemiology of acute poisoning in Shenyang. The findings demonstrated that more females than males had acute poisoning and the most vulnerable age group was the young-adult group aged 20-29. We also observed that the majority of poisoning cases were intentional, particularly suicidal in nature, and accidental poisonings were non-negligible. Our study indicated that therapeutic drugs were the most commonly used toxic agent group, followed by pesticides, alcohol and noxious gas. In addition, the pattern of acute poisoning was slightly altered when compared with 10 years ago. Poisoning due to analgesics and cold and cough preparations was more frequent than poisoning due to psychotropics in the therapeutic drugs poisoning group. In addition, poisoning due to paraquat and rodenticide exceeded poisoning due to organophosphate in the pesticide poisoning group.
Some suggestions are proposed based on the present study and include the    Sedatives/hypnotics in the therapeutic drugs group and paraquat in the pesticides group were the most common toxic agents, respectively. The mortality rate of study participants was 1.3% with 64 deaths.

Conclusions:
The results of this study indicate the need to strengthen education regarding management of the rational and safe use of drugs in Shenyang.

Strengths and limitations of this study:
The cross-sectional and retrospective study design included over 5,000 poisoning cases in 5 consecutive years.
Although the sample size in this study was large, its retrospective nature made it difficult to obtain complete information in all poisoning cases, which may have introduced bias.
Data from a single centre teaching hospital, even with three branches, may not reflect the precise situation in this region.

Introduction
Acute poisoning is defined as acute exposure (less than 24 h) to a toxic substance. [1] Acute poisoning is a major public and preventable health issue contributing to morbidity and mortality in many parts of the world. It is estimated that poisoning events are responsible for more than one million illnesses annually. [2,3] Low mortality contrasts with high morbidity in acute poisoning; however, patients who attempt suicide usually have higher mortality. [4][5][6] As the most common form of fatal self-harm in rural Asia, poisoning accounts for more than 60% of deaths. [7] China is a developing country transitioning from an agricultural to an industrialized economy. In recent years, the number of acute poisoning cases in China has continued to increase, [8] and both poisoning and injury are now two of the top five causes of death. [9] Of the various types of poisoning, pesticide poisoning is the most  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59  60   F  o  r  p  e  e  r  r  e  v  i  e  w  o  n  l  y   4 and food (9.7%); (ii) the major medicines were sedatives/hypnotics and the major pesticides were organophosphates; (iii) mortality decreased from 2.1% to 0.4% over the 10-year study period, with an average mortality rate of 1.0%. [16] In the last few decades, China has witnessed significant advancements in the fields of agriculture, industrial technologies and medical pharmacology. These advancements have been paralleled by marked changes in the trends of acute poisoning, [17] and has led to the development and easy accessibility of a vast number of toxic agents including pesticides, therapeutic drugs and other chemicals. Thus, the toxic agents associated with morbidity and mortality and the pattern of acute poisoning, which vary from place to place and over time, are expected to change.  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59 1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59  60   F  o  r  p  e  e  r  r  e  v  i  e  w  o  n  l  y   6 product was categorized as an adverse reaction. (4) If information was unavailable the cause of poisoning was categorized as unknown.
Gastric lavage, activated charcoal, intubation, infusion and dieresis therapy, and hemoperfusion were standard treatment protocols for poisoning caused by ingestion.
Hemodialysis was performed when indicated. Special antidotes, naloxone for alcohol poisoning, and Vitamin K1 and acetamide for rodenticide poisoning, were given as indicated. For poisoning with no specific available antidotes, symptomatic treatment was administered.
Patients with normal symptoms, signs and laboratory findings on discharge were categorized as recovery. Patients with normal symptoms and signs but abnormal or unavailable laboratory findings on discharge were categorized as relative recovery.
Microsoft Excel 2007 was used to perform descriptive statistical analyses of the data. The average age was presented as the mean ± standard deviation (SD). To evaluate the differences, a chi-square test was performed using SPSS for Windows, version 21.0. A p value of less than 0.05 was considered significant.

Patient and Public Involvement:
Patients and/or the public were not involved.

Routes of exposure
Among the various routes of exposure, ingestion was the most common (86.2 %), followed by inhalation (11.8%) and contact (2.0%).
However, drug poisoning was significantly more frequent in females than males (71.9% vs. 28.1%).  Figure 4). Eighty-eight percent of pesticide poisonings were suicide attempts, and males were involved in 5% more accidental pesticide poisonings than females. Pesticide poisoning was most frequent during the month of July.

Treatment and Outcome
It was noted that gastric lavage and activated charcoal were administered in 72.5%

Comparison with Previous Findings by Zhao et al.
The female-to-male ratio was 1.5:1 in Zhao's study and 1.2:1 in the present study.
Similar to Zhao's report, the most vulnerable patients were aged 20-29 years, but the percentage in Zhao's study was 37.1% which was higher than that in our study. The  11.4% in this study). The major medicines were sedatives/hypnotics (27.5%) and the major pesticides were organophosphates (8.0%) in the previous study. While in this study, the major toxic agents were sedatives/hypnotics (9.4%) and the major pesticide was paraquat (12.8%).
The average mortality rate was 1.0% and 1.3% in the previous study and this study, respectively.

Discussion
Acute poisoning is one of the most frequent causes of visits to the ED and is a threat to public health. The annual rate of ED visits associated with poisoning varies widely across the world, and ranges from 0.1% to 0.7%. [18,19] Studies in western countries have reported annual rates of ED visits associated with poisoning of approximately 0.3%. [19,20] In the present study, this rate was 0.6%, and a similar percentage (0.6%) was seen in the research carried out by Bulent. [21] As it is not common practice for many poisoned patients to seek medical help in health care institutions, the annual rate of ED visits associated with poisoning recorded by hospitals may be misleading. Therefore, the actual number of poisoning cases may be more than that recorded, and accurate statistical data for poisonings are difficult to estimate. Developed countries also have similar problems in obtaining meaningful poisoning statistics even though they are equipped with advanced systems to collect population health data. [22] This study concluded that the incidence of poisoning in females was slightly higher than that in males, especially among young adults aged 20-29 years, with a female-to-male ratio of 1.2:1. Similar findings have also been reported in Beijing, China [23] (1.2:1) and Sari, Iran [17] (1.2:1). In contrast, male preponderance has been found in some other countries. [24,25] The results of this study showed a difference in poisoning based on age and indicated that the most affected age group was the 20-29 year age group (30.8%) with a secondary peak in the 30-39-year-old group (21.9%). Both intentional and accidental poisoning were common in males and females aged 20-29 years, which is consistent with previous findings in China [16,23] and in other countries [26][27][28] . The fact that poisoning is more common among young adults reflects their vulnerability to stress, possibly due to failure or frustration in relationships or exams, maladjustment and inability to cope with the high expectation of parents. [29,30] Overall, this group of people is not emotionally stable or mature enough to tolerate extreme mental or physical pressure. [31,32] Intentional poisoning (suicide+abuse) was the predominant cause of poisoning (78.8%) in the current study, an observation that is consistent with that in other studies. [27,33] Our study indicated that of all poisoning cases, a large proportion were suicidal in nature, but the incidence was lower compared with Zhao's study. This change may be related to the benefits of socioeconomic achievement and prosperity, such as higher employment and more educational opportunities, which may have contributed to the reduction in suicide rates in China. [34] Despite this decline in suicide rate, suicide attempt is still the primary reason for poisoning due to the general belief that poisons terminate life with minimal suffering. [35,36] Our study demonstrates that therapeutic drugs are the most frequently used toxic agents. A similar pattern of therapeutic drugs as the most common cause of acute poisoning has been observed in developed and some developing countries. [37][38][39][40][41][42] With regard to the subgroup of therapeutic drugs in poisoning cases, sedatives/hypnotics were common in Taiwan, Hong Kong, Iran and Finland, while analgesics were the most frequently ingested drugs in Turkey and the USA. Pharmaceutical poisoning comprised 32.6% of the various drug poisonings observed in the present study, of which sedatives/hypnotics (28.8%) were the most frequently ingested agents. A similar pattern was also seen Zhao's study, although an apparent decline in sedatives/hypnotics poisoning was seen in our study. [16] This decline may be connected with the implementation of drug classification control where patients can only access these drugs with a doctor's prescription. [43] However, a rise was observed in the use of analgesics, cold and cough medicines, mixed drugs, as well as cardiovascular drugs, resulting in a different pattern to that seen previously. This may be explained by the easy availability of pharmaceuticals due to the numerous drugstores in China, inadequate governmental supervision, insufficient knowledge about rational use of analgesics, [44] increase in the incidence of cardiovascular disease, [45] and poor psychological well-being and mental fragility among populations. [46] In addition, we found that the frequency of psychotropic drugs poisoning, has increased, which indicates that mental disorder plays a part in poisoning events and should receive attention. It is noteworthy that the number of opioid poisonings is surprisingly small in our study, and this is associated with the government's strict regulation on opioids, insufficient knowledge on opioids in physicians and patients (such as excessive worry about addiction and adverse events), making the use of opioids rare. [47,48] Pesticide poisoning has occurred relatively frequently for some time, as shown by previously published papers from different countries. [33,36] The incidence of this type of poisoning varies geographically and historically. [49] Several studies conducted in India, Sri Lanka and Bangladesh showed a pesticide-dominant poisoning pattern, with organophosphates being the most common pesticide. [50][51][52] Pesticides were the second leading cause of acute poisoning in this study, accounting for 26.6% of all poisoning cases and showed an increased trend. [16] There are two reasons for this increased frequency: first, suicide by pesticide poisoning is still high in China, although suicides related to pesticide poisoning in China have continuously declined from 2006 to 2013. [53] Previous studies have shown that highly lethal pesticides are commonly used in suicide in rural China. [54,55] Our study showed that up to 88% of pesticide poisonings were suicide attempts. Second, pesticides are used extensively and unsafely in agriculture and industry, and can be stored in the home, causing toxicity due to intentional and accidental exposure. [55] The quantity of pesticide use is large and ever-increasing, and has grown from 1.3 million ton in 2001 to 1.8 million ton in 2014. [56] In the present study, paraquat was the most frequently used pesticide, and a similar pattern was found in a study carried out in northeast China which showed an increasing trend, [57] whereas a decreasing trend was found in Korea. [58] Not surprisingly, our study found that alcohol poisoning was common and accounted for 20.7% of all poisoning cases. The incidence of alcohol poisoning increased compared to previous figures in Zhao's study (14.1%). This change can be explained by rapid social and economic development, urbanization, increased alcohol production, and alcoholic beverage commercials in the mass media, which have all led to an increase in alcohol consumption. [59] According to recent data, the annual per-capita alcohol consumption in Chinese adults in 2012 was 3 L. [60] Findings reported elsewhere in China showed a higher number of alcohol poisonings. [61] Alcohol poisoning in other countries has been shown to be lower. [38,[62][63][64] This discrepancy is partially related to the disparity in alcohol consumption habits between different countries and districts. In Chinese culture, people often urge companions to drink as much as possible so that they can construct social connections and establish a happy and congenial atmosphere. [65] This can also explain the gender difference in poisonings, as males are more engaged in social intercourse than females. In addition to widely practiced social drinking, solitary drinking is also common for stress reduction and coping among Chinese. [66] The current data showed that the fourth leading cause of acute poisoning was fumes/gases/vapors (mainly CO), which decreased from 12.5% in Zhao's study to less than 11.4% in our study despite remaining in fourth place. This reduction is related to the improvement in dwelling conditions and preventive education on CO poisoning.
With improvements in heating measures and advances in the fuel switching project from coal to natural gas in rural areas, a further decline in CO poisoning is expected in rural areas in China. There was a significant association between residency and month and reason for exposure to CO. Rural residents are more susceptible to CO poisoning than urban citizens, as local residents in remote villages in northern China use stoves to keep warm in winter, which can result in gas leaks due to a chimney jam and lack of ventilation, and are common causes of CO poisoning in these areas. In contrast, CO poisoning in urban citizens may be explained by eating barbecued food and hotpots, well-known traditional Chinese cuisine that both require charcoal as fuel. [67] In addition, almost all CO poisoning cases in our study were accidental, with the exception of one case of suicide.
In our study, the rate of patients staying in hospital for less than 48 h is small compared with other studies. This was due to patients with poisoning usually being asked to remain in the observing room (available in our ED) for 48 h to 72 h in consideration of the complex doctor-patient relationship in China.
Our study was primarily limited by its retrospective nature, which resulted in missing patient data. Another limitation was that the data from a single centre teaching hospital, even with three branches, may not reflect the precise situation in this region. Hence, extensive data collection and analysis from other general hospitals in the region may depict the pattern of regional poisoning more accurately. In addition, the comparison between the two studies was rudimentary due to the absence of data standardization.

Conclusion and Suggestions
The present data provide additional insight into the epidemiology of acute poisoning in Shenyang. The findings demonstrated that more females than males presented with acute poisoning and the most vulnerable age group was the young adult group aged 20-29 years. We also observed that the majority of poisoning cases were intentional, particularly suicidal in nature, and accidental poisonings were non-negligible. Our study indicated that therapeutic drugs were the most commonly used toxic agent group, followed by pesticides, alcohol and noxious gas. In addition, the pattern of acute poisoning was slightly altered when compared with 10 years ago.
Poisoning due to analgesics and cold and cough medicines was more frequent than poisoning due to psychotropics in the therapeutic drugs poisoning group. In addition, poisoning due to paraquat and rodenticide exceeded poisoning due to organophosphate in the pesticide poisoning group.