Association Between Obesity and Asthma among Adults: A Hospital Based Case-Control Study

The aim is to study the association between obesity and asthma among adults by gender. The prevalences of both asthma and obesity have increased substantially in recent decades, leading to speculation that obese individuals might be at risk of asthma. However, the evidence of a relationship between obesity and asthma is not fully conclusive among adults. Hence we investigate the association between obesity and asthma among men and women using both measured weight and height and self-reported weight and height while controlling for the effects of the demographic and environmental factors. This case-control study involves a total of 159 adults; 53 cases and 106 controls enrolled in the month of July 2009 at PSG Hospitals. Body Mass Index (BMI) was calculated based on measured weight and height. The Odds Ratio (OR) with 95% confidence interval for obese individuals was estimated using logistic regression analysis with SPSS 11.5 for windows software (SPSS Inc., Chicago, Illinois). Multivariate logistic regression model was used to adjust all risk estimates for covariates. Obese women were found to have 9.14 times the risk of asthma than non obese women (95% confidence interval (CI):1.38, 35.68) after adjusting for covariates, such as age, education, environmental tobacco smoke and pet keeping. No significant association was observed among men although the direction of association is positive; adjusted odds ratio was 1.06 (95% CI: 0.12, 9.70). No significant association was observed between self-reported prevalence of obesity and asthma; among women, adjusted odds ratio = 4.33 (95% CI: 0.69, 27.37); and among men, adjusted odds ratio = 0.89 (95% CI: 0.11, 7.12). The study indicates a strong positive association between obesity and asthma among adult Indian women. The causal links between obesity and asthma by gender need to be further examined using prospective cohort studies.