Study of the prevalence of asthma in adults in North India using a standardized field questionnaire.

Prevalence of asthma was calculated using a Hindi adaptation of the International Union Against Tuberculosis and Lung Disease (IUATLD)-1984 questionnaire. The questionnaire was administered to patients with and without asthma to select specific items to define asthma. Questionnaire validity was tested against physician-diagnosed asthma in 753 individuals in the field, with sensitivity and specificity of 63.1% and 98.8%, respectively. The field prevalence study was conducted among 958 men and 1158 women. True population prevalence, calculated from the observed prevalence using specificity and sensitivity of the questionnaire, was 3.94% in urban men, 3.99% in rural men, and 1.27% in both urban and rural women.