Co-exposure to multiple fine particulate matter constituents and adults obstructive sleep apnoea (OSA) in Southern China.

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder. OSA affects approximately 936 million individuals globally and 176 million in China. Nevertheless, the effects of PM2.5 constituents on OSA remains unclear. We aimed to evaluate long-term impacts of PM2.5 components [ammonium (NH4+), sulfate (SO42-), nitrate (NO3-), organic matter (OM), and black carbon (BC)] on OSA indices and identity the dominant component. We carried out a cross-sectional study, incorporating long-term exposures utilizing a database (n = 3925) encompassing 21 cities in Guangdong Province from 2005 to 2015. We illustrated the effects of each PM2.5 component using Generalized Linear Model (GLM) and the joint effect of PM2.5 constituent mixture and the dominant PM2.5 constituent using Bayesian kernel machine regression (BKMR). We found the per IQR increase in 3-year average SO42-, NH4+, OM, and BC concentrations were positively associated with mild OSA, with odds ratios ranging from 1.17 to 1.22. SO42- and BC were associated with 22 % higher odds of mild OSA. Moreover, significant associations were found between the 3-year average levels of PM2.5 and its five constituents and the apnea-hypopnea index (AHI), minimum blood oxygen saturation (MinSpO2), and MeanSpO2. NH4+ and BC exhibited the strongest positive effects on AHI, meanwhile, SO42- and BC showed the greatest negative effects on MinSpO2 and MeanSpO2. Age-specific effects and gender-specific associations between PM2.5 and its constituents and OSA indexes were also observed. Significant impacts were noted in females and participants aged<65 years. Our study provides the first local evidence linking specific PM2.5 chemical constituents to OSA indices and addresses a knowledge gap in the fields of environmental epidemiology and sleep-disordered breathing.