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

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 PM_2.5 constituents on OSA remains unclear. We aimed to evaluate long-term impacts of PM_2.5 components [ammonium (NH₄⁺), sulfate (SO₄^2-), 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 PM_2.5 component using Generalized Linear Model (GLM) and the joint effect of PM_2.5 constituent mixture and the dominant PM_2.5 constituent using Bayesian kernel machine regression (BKMR). We found the per IQR increase in 3-year average SO₄^2-, NH₄⁺, OM, and BC concentrations were positively associated with mild OSA, with odds ratios ranging from 1.17 to 1.22. SO₄^2- and BC were associated with 22 % higher odds of mild OSA. Moreover, significant associations were found between the 3-year average levels of PM_2.5 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, SO₄^2- and BC showed the greatest negative effects on MinSpO₂ and MeanSpO₂. Age-specific effects and gender-specific associations between PM_2.5 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 PM_2.5 chemical constituents to OSA indices and addresses a knowledge gap in the fields of environmental epidemiology and sleep-disordered breathing.