Cigarette smoking status and the association between media use and overweight and obesity.

For biologic and behavioral reasons, cigarette smokers weigh less than nonsmokers. Thus, cigarette smoking may modify the association between media use and obesity. The authors examined whether the association between media use and overweight and obesity was modified by cigarette smoking by analyzing 8,467 adults (> or =20 years) from the 1999-2002 National Health and Nutrition Examination Survey. Odds ratios and 95% confidence intervals of overweight and obesity were estimated by use of multinomial regression. To examine effect modification, the authors created separate regression models for smokers and nonsmokers (p(interaction) = 0.002). Nonsmokers using media 4 or more hours daily were 3.9 times more likely to be obese (95% confidence interval (CI): 2.9, 5.2) and 1.6 times more likely to be overweight (95% CI: 1.3, 2.0) compared with those reporting less than 1 hour/day of media use. Among smokers, media use 4 or more hours daily was not significantly associated with increased odds of obesity (odds ratio = 1.3, 95% CI: 0.8, 2.2) or overweight (odds ratio = 1.4, 95% CI: 1.0, 1.9). Media use was associated with overweight and obesity and modified by cigarette smoking. Cigarette smoking should be evaluated as an effect modifier in studies of media use and obesity.