The association between amount of cigarettes smoked and overweight, central obesity among Chinese adults in Nanjing, China

Objectives: To examine the association between overweight, central obesity and cigarette smoking (total amount of cigarettes smoked [TACS] and status). Design: Population-based cross-sectional study. Setting: Administrative villages and neighborhoods (n=45) randomly selected from three urban districts and two rural counties in Nanjing City, China. Subjects and methods: A representative sample (n=13,463) of permanent local male residents aged 35 years or older; 66.5% were urban residents. The response rate was 90.1%. Overweight (BMI>=24) and central obesity (waist circumference>=85 in men) were defined according to the new Chinese standard. The association between smoking (amount and status) and obesity was examined using logistic and linear regression analysis. Results: The overall prevalence of overweight was 36.1% (29.7% with 24<=BMI<28 and 6.4% with BMI>=28). After adjusted for age, residence, education, occupation, family income, alcohol drinking, dietary intake, occupational and leisure-time physical activity, the prevalence was significantly lower among current smokers (33.0%) than in non-smokers (39.9%) and ex-smokers (39.2%), respectively (p<0.05). The amount of cigarette smoked was reversely associated with BMI (compared to non-smokers, ORs and 95%CIs for smokers with low-, medium- and high-TACS were 0.88 [0.79, 0.98], 0.77 [0.69, 0.86], and 0.77 [0.69, 0.86], respectively). The prevalence of central obesity was 35.9%. Compared to nonsmokers, only male ex-smokers were at increased risk of central obesity (OR=1.38, 95%CI=1.10, 1.74), while there was no significant association with current-smokers (OR=1.02 [0.92, 1.12]). The amount of cigarette smoked was not significantly associated with central obesity. Conclusions: Cigarette smoking was negatively associated with body weight indicated by BMI but not with central obesity indexed by waist circumference in Chinese men. Cessation of smoking may increase the risk of gaining overall body weight and developing central obesity. Cigarette smoking prevention and cessation should be a public health priority in China.