Risk factors for development of bronchial asthma in children in Delhi

Background: Information on the magnitude of the problem of childhood asthma in India and the factors influencing its occurrence is inadequate. Objective: To measure the prevalence of asthma in schoolchildren in Delhi and study the factors determining its occurrence. Methods: A questionnaire-based study carried out in nine randomly selected schools in Delhi. The age range was 5 to 17 years. The questionnaires were distributed to all the children (n = 21,367) for answering by either parent. The key questions relate to complaints of recurrent wheezing in the past, during the immediate last 1-year, and also wheezing exclusively induced by exercise or colds. In all, 19,456 questionnaires were received back (response rate 91%). Out of these, 18,955 were complete and analyzed. Results: The prevalence of current asthma was 11.9% while past asthma was reported by 3.4% of children. Exclusive exercise-induced asthma was reported by 2.1% while that associated with colds by 2.4% of children. Boys had a significantly higher prevalence of current asthma as compared with girls (12.8% and 10.7%, respectively). Multiple logistic regression analysis showed that male sex, a positive family history of atopic disorders, and the presence of smokers in the family were significant factors influencing the development of asthma while economic class, air pollution (total suspended particulates), and type of domestic kitchen fuel were not. Conclusions: The prevalence of current asthma in children in Delhi is 11.9%. Significant risk factors for its development are male sex, a positive family history of atopic disorders, and the presence of smokers in the family.