Association between smoking status and metabolic syndrome in Korean adults: Korean National Health and Nutrition Examination Survey (KNHANES 2007–2010)

Abstract

Objective: Smoking is well known to increase the risk of type-2 diabetes. However, it is controversial whether smoking increases insulin resistance. This study aimed to evaluate the association between smoking status and metabolic syndrome (MetS) in Korean population. Methods: Study subjects were 18,818 participants (≥19 years) from the Korean National Health and Nutrition Examination Surveys (2007–2010). Smoking status was assessed using self-administered questinnaire and components of MetS were measured. The presence of Mets was ascertained according to National Cholesterol Education Program/Adult Treatment Panel III (NCEP/ATP III) criteria but for abdominal obesity using definition of Korean Society for the Study of Obesity: abdominal obesity defined as a waist circumference in men ≥90 cm and in women ≥85 cm, serum triglycerides ≥150 mg/dL (1.7 mmol/L) or drug treatment for elevated triglycerides, serum HDL cholesterol <40 mg/dL (1 mmol/L) in men and <50 mg/dL (1.3 mmol/L) in women or drug treatment for low HDL-C, blood pressure ≥130/85 mm Hg or drug treatment for elevated blood pressure, fasting plasma glucose (FPG) ≥100 mg/dL (5.6 mmol/L) or drug treatment for elevated blood glucose. Logistic regression analysis was done to evaluate the association between smoking status and MetS with an adjustment for age, education, physical activity, alcohol consumption, total fat intake, total fiber intake, and body mass index. Results: Compared with never-smoker, MetS was more prevalent in both current smokers (odds ratio (OR) = 1.53; 95% confidence interval (CI) 1.20, 1.95) and past smokers (OR = 1.31; 95% CI 1.04,1.65) in men, while the prevalence of MetS was higher among current smokers (OR = 1.72 95% CI 1.23,2.42) in women. For components of MetS, male current smokers had an increased risk of abdominal obesity (OR = 1.65, 95% CI 1.23, 2.22), high triglyceride (OR = 1.87, 95% CI 1.56,2.25), and low level of high density lipoprotein cholesterol (OR = 1.36, 95% CI 1.12, 1.66) and decreased risk of high blood pressure (OR = 0.81, 95% CI 0.67, 0.97) compared with never-smokers. Female current smokers showed increased risk of abdominal obesity (OR = 1.60, 95% CI 1.13, 2.26), high triglyceride (OR = 1.96, 95% CI 1.48, 2.58), and low level of high density lipoprotein cholesterol (OR = 1.39 95% CI 1.05,1.84). Conclusion: Smoking was associated with increased risk of MetS and individual metabolic components in Korean adults.