Polycyclic aromatic hydrocarbons are associated with sleep-related disorders in adults: the potential mediating role of inflammation

Background The evidence on the effects of polycyclic aromatic hydrocarbons (PAHs) on sleep disorders is limited. This study aimed to explore the association between PAH exposure and sleep-related disorders, and the potential mediating roles of inflammation in these relationships were further been examined. Methods This study utilized data from adult participants (>= 20 years of age) in the US National Health and Nutrition Examination Survey 2005-2008. Weighted logistic regression models were used to estimate the associations between each urinary PAH biomarker and sleep-related disorders. Structural Equation Modelling (SEM) was applied to evaluate the association between PAH exposure and sleep-related disorders and to assess the mediating effect of inflammatory markers that include C-reactive protein (CRP) and white blood cell counts (WBC). Results One or more urinary PAH metabolites were associated with an increased risk of long sleep-onset latency, obstructive sleep apnea (OSA), sleep problems, and daytime sleepiness. The latent PAH exposure variable in SEM was positively associated to long sleep-onset latency (beta = 0.054, p = 0.035), OSA (beta = 0.071, p = 0.002), sleep problems (beta = 0.089, p < 0.001) and daytime sleepiness (beta = 0.066, p = 0.003). Mediation analysis suggested that WBC mediated the link between PAH exposure and sleep problems (Indirect effect = 0.009, 95%CI: 0.002 similar to 0.017, Proportion: 10.8%), as well as daytime sleepiness (Indirect effect = 0.011, 95%CI: 0.005 similar to 0.019, Proportion: 15.7%). Conclusions PAH exposure was associated with an increased risk of long sleep-onset latency, obstructive sleep apnea, sleep problems, and daytime sleepiness. Inflammation may be one potential mechanism by which PAH exposure contributes sleep problems and daytime sleepiness.