{'fraction_non_alphanumeric': 0.05023094688221709, 'fraction_numerical': 0.05658198614318707, 'mean_word_length': 4.112094395280236, 'pattern_counts': {'":': 0, '<': 2, '<?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': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Prevalence of Unruptured Cerebral Aneurysms in Chinese Adults Aged 35 to 75 Years

BACKGROUND
The reported prevalence of unruptured cerebral aneurysms (UCAs) varies widely.


OBJECTIVE
To measure the prevalence of UCAs by using 3-dimensional time-of-flight magnetic resonance angiography in adults aged 35 to 75 years.


DESIGN
Cross-sectional study done between June 2007 and June 2011.


SETTING
Two communities chosen at random from 2 districts (1 urban and 1 suburban) in Shanghai, China.


PARTICIPANTS
4813 adults aged 35 to 75 years.


MEASUREMENTS
Three-dimensional time-of-flight magnetic resonance angiography, interpreted by 3 observers blinded to the participants' information, was used to identify the location and size of UCAs and to estimate the overall, age-specific, and sex-specific prevalence.


RESULTS
369 UCAs were found in 336 participants (130 men and 206 women); 4477 participants had no evidence of UCAs. The prevalence was 7.0% overall (95% CI, 6.3% to 7.7%), with 5.5% for men (CI, 4.6% to 6.4%) and 8.4% for women (CI, 7.3% to 9.5%). The overall prevalence of UCAs was higher in women than in men (P < 0.001) and peaked at ages 55 to 64 years in men and women. The UCAs were mostly located in the internal carotid artery (81%), and 90.2% had a maximum diameter less than 5 mm. Mean diameter was larger in women than in men (3.7 mm vs. 3.2 mm; P < 0.009).


LIMITATION
Participants were from 2 communities selected from 2 districts in Shanghai, and adults older than 75 years were not studied.


CONCLUSION
The overall prevalence of UCAs was 7.0% in Chinese adults aged 35 to 75 years, and most lesions had a diameter less than 5 mm.


PRIMARY FUNDING SOURCE
National Natural Science Foundation of China.