Smoking-Related Differential Influence of Alcohol Consumption on the Metabolic Syndrome

Background: There is a high propensity toward combined alcohol consumption and smoking. The aim of the study is to determine whether the association of alcohol consumption and the metabolic syndrome (MS) were different in among groups stratified by smoking exposure. Methods: Subjects consisted of 4,672 adult participants in the 2008 Korea National Health and Nutrition Examination Survey grouped into three categories of smoking using urinary cotinine concentration. Drinking categories were as follows: lifetime abstainers, ex-drinkers, responsible drinkers (<20 g alcohol/day for women; <40 g/day for men), and hazardous drinking (≥ 20 g/day for women; ≥ 40 g/day for men). Results: Compared with nonsmokers, heavy smokers had a higher risk of the MS (OR: 1.27, 95% CI: 1.00-1.62, p = .052). One standard deviation-higher urinary cotinine was also associated with higher risk of the MS (OR: 1.12, 95% CI: 1.03-1.23, p = .011). In nonsmokers and light/moderate smokers, alcohol had no effect on the MS. In heavy smokers, the risk of the MS was substantially higher in ex-drinkers (OR: 3.42; 95% CI: 0.99-11.82), responsible drinkers (OR: 2.80; 95% CI: 0.96-8.12), and hazardous drinkers (OR: 3.30; 95% CI: 1.21-9.03, p = .02) compared to lifetime abstainers. A profound effect modification of alcohol by smoking was found in current drinkers. Conclusions: Smoking is closely associated with the MS. Alcohol has detrimental effect on the risk of MS in heavy smokers and the effect of alcohol is enhanced by smoking.