Association between tobacco use and body mass index in urban Indian population: implications for public health in India

Background: Body mass index [BMI, weight ( kg)/height (m(2))], a measure of relative weight, is a good overall indicator of nutritional status and predictor of overall health. As in many developing countries, the high prevalence of very low BMIs in India represents an important public health risk. Tobacco, smoked in the form of cigarettes or bidis ( handmade by rolling a dried rectangular piece of temburni leaf with 0.15 - 0.25 g of tobacco) or chewed, is another important determinant of health. Tobacco use also may exert a strong influence on BMI. Methods: The relationship between very low BMI (< 18.5 kg/m(2)) and tobacco use was examined using data from a representative cross-sectional survey of 99,598 adults ( 40,071 men and 59,527 women) carried out in the city of Mumbai ( formerly known as Bombay) in western India. Participants were men and women aged >= 35 years who were residents of the main city of Mumbai. Results: All forms of tobacco use were associated with low BMI. The prevalence of low BMI was highest in bidi-smokers (32% compared to 13% in non-users). For smokers, the adjusted odds ratio ( OR) and 95% confidence interval (CI) were OR = 1.80(1.65 to 1.96) for men and OR = 1.59(1.09 to 2.32) for women, respectively, relative to non-users. For smokeless tobacco and mixed habits ( smoking and smokeless tobacco), OR = 1.28(1.19 to 1.38) and OR = 1.83(1.67 to 2.00) for men and OR = 1.50(1.43 to 1.59) and OR = 2.19(1.90 to 3.41) for women, respectively. Conclusion: Tobacco use appears to be an independent risk factor for low BMI in this population. We conclude that in such populations tobacco control research and interventions will need to be conducted in concert with nutrition research and interventions in order to improve the overall health status of the population.