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Chronic respiratory disease among pulp mill workers in an arctic area in Northern Finland.

. A total of 953 pulp mill workers have been examined, using a standardized questionnaire, ventilation tests, and chest roentgenography, to determine the prevalence and aetiology of respiratory symptoms and chronic non-specific lung disease (CNSLD) in an industrial population from an arctic area in Northern Finland. About 10% of the men had (active or inactive) pulmonary tuberculosis or “other respiratory disease”, as defined. After their exclusion there remained 812 men averaging 37.9 years (range 18–64 years) for the main study. 
 
 
 
The group of 812 men consisted of 20% non-smokers, 21 % ex-smokers and 59 % smokers, but only 8 % smoked 25 g or more daily. Age had no substantial effect on the smoking habits, although the number of ex-smokers increased slightly with age. Only 81 men (10% of the total) smoked cigars and/or pipe, the others smoking cigarettes. 
 
 
 
In all age groups the smokers coughed more and produced more phlegm than did the non-smokers and ex-smokers; the frequency of symptoms increased with the amount smoked daily. Dyspnoea, wheezing, and temporary chest illnesses also were more common among smokers. The effect of age on the prevalence of respiratory symptoms (excluding dyspnoea and effects of weather) remains uncertain. 
 
 
 
The prevalence of chronic bronchitis, diagnosed on the basis of phlegm production, was 27% in the whole material; the prevalence was 11% for non-smokers and ex-smokers, and 49% for those smoking 25 g or more daily. There were only six cases of asthma, and the prevalence of all forms of CNSLD was 29%. 
 
 
 
The smokers showed significantly lower FEV1 and FEV1% values than the non-smokers. There was no such difference in FVC. 
 
 
 
The present investigation was carried out in a cold climate—an area where snow usually covers the ground from October to April. Even in these unfavourable weather conditions smoking proved the most important, though not the only, cause of chronic bronchitis and respiratory symptoms in the population studied. The effects of the cold climate and of the industrial environment appear to be relatively slight and uncertain, and no distinction can be made between them on the basis of this study. 
 
 
 
The mortality from chronic bronchitis and other chronic non-specific lung diseases varies widely from country to country. Prevalence surveys have shown that the morbidity from chronic bronchitis also differs, though to a lesser extent than would be expected on the basis of mortality differences. Smoking, and in places air pollution, has usually been considered the principal cause of chronic bronchitis; other causes suggested are repeated respiratory infections, allergic and hereditary factors, weather conditions, and the abortive form of mucoviscidosis, but opinions are divided as regards the role of each of these factors (25, 26). Industrial workers, especially in dusty occupations, have a higher than average prevalence of chronic bronchitis (6, 7, 15). 
 
 
 
The aim of the present investigation was to study the prevalence of respiratory symptoms and chronic lung diseases in an industrial population in a cold climate, and to call attention to their aetiology. Thus it is possible to obtain a basis for later follow-up studies from which information on the prognosis and natural history of these diseases may be gained.