Effect of Smoking on Body Mass Index: A Community-Based Study

Smoking has a negative effect on Body Mass Index (BMI). This association may be confounded by demographic factors. Secondary analysis of data of 3446 non-smokers and 948 current smokers from a previously published community study on respiratory morbidity in Delhi was carried out to examine the association between smoking and BMI, and the confounding effects of gender and economic status. The BMI values were higher among non- smokers while smokers had a higher proportion of underweights. After adjusting for gender and economic status, the odds ratio for being underweight was 1.34 (95% CI 1.13-1.6) among smokers whereas non-smokers had an adjusted odds ratio for overweight/obesity of 2.16 (95% CI 1.24-3.78). The study shows that smoking is independently associated with reduced BMI after adjusting for gender and economic status in an Indian population.