Prevalence of chronic bronchitis in Rhodesian Africans.

The prevalence of chronic bronchitis in the African population of a small township in Rhodesia was estimated using two questionnaires, both based on those of the British Medical Research Council. The first, a screening questionnaire, was put to 9768 subjects aged 5 years and above and the second, a more detailed questionnaire, to random selections of these grouped according to their replies. Repeat interviews were used to assess the accuracy of the questionnaires. The overall prevalence of chronic bronchitis was 1.12%. This is much lower than most other surveys elsewhere. There was little evidence of an increase in prevalence with age, and rates were not significantly different in the two sexes. The prevalence of complications and of other chest symptoms was correspondingly low. The proportion of bronchitics who smoked was not significantly higher than in the controls. Amounts smoked, however, were generally much lower than in other populations, and this, together with low levels of pollution, probably account for the prevalence findings.