Combined effect of central obesity and urinary PAH metabolites on lung function: A cross-sectional study in urban adults.

BACKGROUND: Central obesity and polycyclic aromatic hydrocarbons (PAHs) exposure were reported as independent risk factors for lung function decline. However, the interaction between central obesity and PAHs exposure on lung function is still unclear.

OBJECTIVES: To evaluate the impact of central obesity, urinary polycyclic aromatic hydrocarbon metabolites (OH-PAHs) and their combined effects on lung function in general population.

METHODS: Lung function and urinary OH-PAHs were measured for 3,749 participants from the Wuhan-Zhuhai cohort. Central obesity was evaluated by waist-to-hip ratio. Generalized linear regression was used to estimate combined effect of central obesity and OH-PAHs on lung function.

RESULTS: Compared with participants without central obesity and with low urinary total OH-PAHs (∑OH-PAHs) level, those with central obesity and high urinary ∑OH-PAHs level had 59.4 mL and 61.0 mL reductions for forced vital capacity (FVC) and forced expiratory volume in 1s (FEV1 ), respectively (P < 0.05). The reductions were more evident in smokers and males. Additive interactions between central obesity and urinary ∑OH-PAHs on lung function were observed, especially on FEV1 (P < 0.05). Each 1-unit increase in log-transformed value of ∑OH-PAHs was associated with -34.4 ml (95% confidence interval [CI]: -66.9, -1.8) and -34.8 mL (-61.1, -8.5) changes in FVC and FEV1 among those without central obesity, while -21.4 ml (-49.9, 7.1) and -19.7 ml (-43.4, 4.0) changes among those with central obesity.

CONCLUSION: Polycyclic aromatic hydrocarbons exposure has combined effect with central obesity on lung function parameters.