Association Between Cotinine-Verified Smoking Status and Metabolic Syndrome: Analyses of Korean National Health and Nutrition Examination Surveys 2008-2010

Background: The association between smoking and metabolic syndrome has not been clarified, especially for women, probably because of the inaccurate self-reported smoking status. This study aimed to investigate the association between cotinine-verified smoking status and metabolic syndrome. Methods: A total of 11,559 participants from the Korean National Health and Nutrition Examination Surveys were included in this cross-sectional study. Metabolic syndrome was determined according to revised National Cholesterol Education Program Adult Treatment Panel III criteria. Smokers were distinguished from nonsmokers by a urinary cotinine level above 50 ng/mL. Multivariable adjusted logistic regression analysis was used to evaluate the association between cotinine-verified smoking status and metabolic syndrome. Results: Prevalence of metabolic syndrome was 28.2% in men and 24.6% in women. Self-reported smoking status was much less consistent with cotinine-verified smoking status in women (kappa values=43.0%) compared with men (kappa value=88.6%). Risk of metabolic syndrome was significantly higher in cotinine-verified smokers than in nonsmokers for both men and women. Among the components of metabolic syndrome, smokers had an increased risk of high triglycerides (TGs), low high-density lipoprotein cholesterol, and decreased risk of high blood pressure compared with nonsmokers in men. In women, smokers had a higher risk of abdominal obesity and high TGs compared with nonsmokers. Conclusions: This population-based study showed that smoking was associated with increased risk for metabolic syndrome in men as well as in women and this association is mainly due to the association between smoking and dyslipidemia.