THE IMPACT OF CIGARETTE AND ALCOHOL-CONSUMPTION ON WEIGHT AND OBESITY - AN ANALYSIS OF 1911 MONOZYGOTIC MALE TWIN PAIRS

Background: The objective of this investigation was to examine the relationships among cigarette and alcohol consumption and weight and obesity. Although previous research demonstrated that smoking is associated with reduced weight, data on the relationship between alcohol consumption and weight are conflicting. In addition, the influence of smoking cessation on the risk of obesity at a level that adversely affects health has not been fully examined. Methods: By means of a cotwin-control research design, cigarette and alcohol consumption and weight measurements derived from 1911 male, monozygotic twins were compared with those of their identical siblings. This approach eliminates confounding from a large number of measurable and unmeasurable environmental experiences and the well-documented influence of inherited factors on weight and cigarette and alcohol consumption. Results: After adjustment for a variety of socioeconomic factors, light (one to 19 cigarettes daily), moderate (20 to 29 cigarettes daily), and heavy (>29 cigarettes daily) smokers were an average of 3.2, 2.4, and 4.0 kg lighter, respectively, than nonsmokers. Past smokers demonstrated a 33% higher prevalence of clinically significant obesity (body mass index >27.8 kg/m2) by comparison with their currently smoking siblings (26.5% vs 19.9%, respectively; difference, P<.001) and a 1.8 times increased risk (95% confidence interval, 1.1 to 2.9) of clinically significant obesity by comparison with heavy smokers. By contrast, alcohol consumption had no significant influence on weight or obesity. Conclusions: Smoking cessation efforts provided by health practitioners to men should consider routinely offering a weight management component to reduce weight gain and further improve the well-documented health benefits of not smoking. It may not be necessary for alcohol treatment programs to adopt a similar policy.