The effect of smoking and sex on the association between long-term alcohol consumption and metabolic syndrome in a middle-aged and older population

Background: The effect of smoking and sex on the relationship between alcohol consumption and risk of developing metabolic syndrome (MetS) and its components has not been investigated. Methods: A total of 5,629 Korean adults aged 40–69 years without MetS were recruited at baseline. Alcohol consumption was assessed biennially, and participants were classified as never, light, moderate, or heavy drinkers. Smoking status was examined at baseline and categorized into non-smokers and current smokers. Risk of incident MetS and its components according to alcohol consumption was examined by smoking status and sex using a multivariate Cox proportional hazards model. Results: During a follow-up of 12 years, 2,336 participants (41.5%) developed MetS. In non-smokers, light or moderate alcohol drinkers had a lower risk of developing MetS, abdominal obesity, hyperglycemia, hypertriglyceridemia, and low HDL-C compared with never drinkers. Heavy alcohol consumption was associated with a higher risk of incident elevated blood pressure (hazard ratio [HR] 1.48; 95% confidence interval [CI], 1.07–2.06; P = 0.020) in men and abdominal obesity (HR 1.86; 95% CI, 1.06–3.27; P = 0.030) in women. However, in smokers, the inverse association of light or moderate alcohol consumption with hypertriglyceridemia and abdominal obesity was not present, whereas a positive association between heavy alcohol consumption and hyperglycemia (HR 1.39; 95% CI, 1.07–1.80; P = 0.014) was observed. Conclusions: Smoking status and sex strongly affects the association between long-term alcohol consumption and MetS and its components by the amount of alcohol consumed.