Relationship between Obesity and Smoking in Korean Men: Data Analyses from the Third and Fourth Korea National Health and Nutrition Examination Surveys (KNHANES)

Background: To assess the cross-sectional associations between smoking and obesity in a national representative sample of Korean men. Methods: We analyzed pooled data from the 3rd Korea National Health and Nutrition Examination Survey (KNHANES III) in 2005 and part of the fourth KNHANES in 2007. Height, body weight, and waist circumference (WC) were measured, and body mass index (BMI) was calculated. Age-adjusted means of BMI & WC were calculated using analysis of covariance. The associations of obesity and abdominal obesity with smoking status were examined using multiple logistic regression analysis. Results: Age-adjusted means of BMI and WC were higher in ex-smokers (N=1,206, BMI 24.4 kg/m 2 , WC 85.3 cm) than both in never smokers (N=725, BMI 24.0 kg/m 2 , WC 84.1 cm) and current smokers (N=1,570, BMI 23.7 kg/m 2 , WC 84.0 cm) (P0.01, respectively). In the subjects aged 47 or older, the risk of obesity in current smokers was significantly lower than in never smokers regardless of smoking amount (P0.01), while there were no differences in obesity risk between ex-smoker and never smoker. On the other hand, some ex-smokers who were less than 47 years old had a significantly higher risk of obesity (adjusted OR=1.56, 95% Confidence Interval [CI], 1.06-2.29 for 11-20 cigarettes per day [CPD]) and abdominal obesity (adjusted OR=2.26, 95% CI, 1.17-4.38; for 21 CPD) than never smokers. Current smokers aged less than 47 with 21 CPD had about a statistically non-significantly 40% higher risk of obesity and abdominal obesity.