标题： Impact of Cigarette Smoking on the Relationship between BMI and Insulin: Longitudinal Observation from the Bogalusa Heart Study.
作者： Li, Ying; Zhang, Tao; Han, Tianshu; Li, Shengxu; Bazzano, Lydia; He, Jiang; Chen, Wei
作者机构：[ Li, Ying; Li Y] Department of Nutrition and Food Hygiene, School of Public Health, Harbin Medical University, Harbin, China., Department of Biostati 更多
来源： Diabetes, obesity & metabolism
摘要： BACKGROUND: Despite the inverse association between cigarette smoking and body mass index (BMI), it is unknown about whether the effect of smoking on insulin is mediated through decreased BMI. This study aims to examine the temporal relationship between BMI and insulin, the impact of smoking on this relationship and mediation effect of BMI on the association between smoking and insulin levels. METHODS: The longitudinal cohort consisted of 1,121 adults (807 whites and 314 blacks, mean age=42.0 years at follow-up) who had BMI and fasting insulin measured twice, with an average follow-up period of 17.1 years. Cross-lagged panel and mediation analysis models were used to examine the temporal relations between BMI and insulin, and mediation effect of BMI on the smoking-insulin association. RESULTS: Smoking was inversely associated with insulin (regression coefficient=-0.073, p=0.015 at baseline and -0.121, p<0.001 at follow-up), adjusting for age, race and gender. After additional adjustment for follow-up periods, the cross-lagged path coefficient from BMI to insulin (beta=0.226, p<0.001) was significantly greater than that from insulin to BMI (beta=-0.029, p=0.208), with p<0.001 for the difference. The path coefficient from BMI to insulin was significantly greater in non-smokers (beta=0.273, p<0.001) than in smokers (beta=0.122, p=0.046), with p=0.013 for the difference. The mediation effect of BMI on the smoking-insulin association was estimated at 53.4% (p=0.030) at baseline and 58.7% (p<0.001) at follow-up. CONCLUSIONS: These findings suggest that cigarette smoking has significant impact on the one-directional relationship from BMI to insulin. The insulin-lowering effect of smoking is predominantly mediated through decreased BMI resulting from smoking.