Prevalence of bronchial asthma in schoolchildren in Delhi

There is a paucity of information on the prevalence of asthma in children in India. Some evidence suggests that asthma is less common in developing than in the developed countries. The present study was carried out to estimate its current magnitude in children in Delhi. The questionnaire-based study was carried out in two randomly selected schools in Delhi. All the children were eligible. The age range was 4-17 years. The questionnaires were distributed to all the children present (n = 2867) to be answered by either parent. The key questions were related to complaints of recurrent wheezing in the past, in the last 1 year, and also wheezing exclusively induced by exercise or colds. In all, 2609 questionnaires were completed and returned (response rate 91%). There was a slight excess of males (54%). The prevalence of current asthma was 11.6% and past asthma was reported by 4.1% of children, giving a cumulative prevalence of 15.7%. Exclusive exercise-induced asthma was 2.8% and that associated with colds, 2.3%. The current prevalence of all wheezing was thus 16.7% and cumulative prevalence was 20.8%. While there was no sex-related difference in prevalence, wheezers were the highest in the 9-13 year age group. A significant association was found between the prevalence of wheezing and a family history of asthma (odds ratio 3.65) and presence of smokers in the family (odds ratio 1.62). When both the above factors combined, the odds ratio for risk of asthma was 4.58. There was no significant association with any economic class. Only 11% of asthmatics had been labeled so by their physicians. The prevalence of bronchial asthma and wheezing in children in Delhi is quite high and comparable to that reported from several developed countries. A positive family history of asthma and presence of smokers in the family emerged as significant risk factors.