Systemic inflammation and polycyclic aromatic hydrocarbons jointly accelerate lung function decline: Evidence from the Wuhan-Zhuhai cohort

Systemic inflammation has been implicated as an important hallmark of cardiovascular disease, asthma, and aging. However, its adverse effect on lung function in the general population, along with its combined impact with polycyclic aromatic hydrocarbons (PAHs) exposure remains largely unknown. We developed a systemic inflammation score incorporating white blood cell (WBC) count, high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), interleukin-22 (IL-22), and club cell secretory protein-16 (CC16), based on biomarker-lung function associations identified in a panel study of 221 observations (n = 120). Using data from the Wuhan-Zhuhai (WHZH) cohort (5662 observations), we examined the cross-sectional and longitudinal associations of the systemic inflammation score and urinary mono-hydroxylated PAH metabolites (OH-PAHs) with lung function. Each unit increase in the inflammation score was associated with reductions in forced expiratory volume in 1 s (FEV₁) (-6.94 mL), forced vital capacity (FVC) (-8.03 mL), and peak expiratory flow (PEF) (-14.50 mL/s). Longitudinal analysis revealed that participants with consistently high inflammation scores experienced accelerated annual declines in FEV₁ (-13.41 mL/year), FVC (-19.04 mL/year), and PEF (-93.51 mL/s·year) compared to those with consistently low scores. Although OH-PAHs were not significantly associated with inflammation scores, participants with high levels of both OH-PAHs and inflammation scores exhibited significantly lower lung function (FEV₁: -132.20 mL; FVC: -155.80 mL) than those with low levels of both. Our findings suggest that systemic inflammation is independently associated with lung function decline, and its combination with PAH exposure accelerates this process. These results highlighted the importance of monitoring systemic inflammation in environmental exposures related respiratory impairment in the general population.