Exposure to polycyclic aromatic hydrocarbons and central obesity enhanced risk for diabetes among individuals with poor lung function.

Some studies have shown an association between obesity or exposure to polycyclic aromatic hydrocarbons (PAHs) and the risk of diabetes. This study aimed to investigate the interaction of obesity and urinary monohydroxy-PAHs (OH-PAHs) on diabetes. Individuals (n = 2716) were drawn from the baseline survey of the Wuhan-Zhuhai Cohort Study. They completed the physical examination, measurements of lung function, biochemical indices and urinary OH-PAHs levels. Additive effect of obesity and urinary ΣOH-PAHs levels on diabetes was assessed by calculating the relative excess risk due to interaction (RERI) and the attributable proportion (AP) due to interaction. Several urinary OH-PAHs were positively associated with diabetes in individuals with central obesity or normal weight (p < 0.05 for all). Among individuals with poor lung function, the RERI between urinary ΣOH-PAHs and waist circumstance (WC, RERI: 0.866, 95% CI: -0.431, 2.164, p = 0.192) or waist-to-height ratio (WHtR, RERI: 1.091, 95% CI: -0.124, 2.305, p = 0.078) was found; the AP due to the interaction between urinary ΣOH-PAHs and WC or WHtR was 0.383 (95% CI: -0.07, 0.80, p = 0.086) or 0.465 (95% CI: 0.019, 0.912, p = 0.04). The results indicated that central obesity may enhance the effect of exposure to background PAHs on diabetes in individuals with poor lung function.