Epidemiological aspects of chronic bronchitis in shimla hills

Objectives. To study the prevalence and epidemiological aspects of chronic bronchitis in the rural and urban population residing in Shimla hills, and its relationship with various risk factors. Methods. A cross-sectional study was conducted on 1330 subjects above 18 years of age in urban and rural areas of Shimla District, Himachal Pradesh. The study sample was selected equi-proportionately from rural and urban areas. Chronic bronchitis was defined based on clinical case definition given by Medical Research Council (MRC). A proforma based on MRC questionnaire was designed and pre-tested in both urban and rural population. Later, peak expiratory flow rate (PEFR) was measured for the cases diagnosed from the questionnaire. Results. The overall prevalence of chronic bronchitis based on clinical case definition was 9.1 percent. The prevalence of chronic bronchitis was significantly more in males (11.1%) as compared to females (6.1%). It increased with age and was greater in rural areas (13.5%) as compared to urban areas (4.7%). Non-filtered cigarette smokers had significantly higher prevalence of chronic bronchitis as compared to filtered cigarette smokers. Conclusions. After adjusting for other variables, prevalence of chronic bronchitis was significantly associated with heating source, age, area of residence and lower socio-economic status.