Alterations in cardiometabolic markers associated with Canada-wide and sector-specific multiple air pollutant...

Existing evidence on air pollution exposure and cardiometabolic biomarker associations does not consider pollution mixtures and sector-specific pollution contributions. Participants from the cross-sectional Canadian Health Measures Survey (2007-2019) were included. Annual average concentrations of ambient PM_2.5, SO₂, NO₂, and O₃ (2006-2019) were modeled using the Global Environmental Multi-scale - Modelling Air quality and Chemistry (GEM-MACH) chemical transport model at a 10 km by 10 km surface resolution from all sources combined as well as from eight specific sectors. The quantile g-computation model was used to estimate changes in lipid and glucose metabolic markers associated with interquartile increases in air pollution. A total of 30,781 participants aged 3-79 years were included in the study. Exposure to PM_2.5, O₃, NO₂, and SO₂ from all sectors was associated with increases in the ratio of total cholesterol to HDL (0.039, 95 % CI: 0.017,0.060), apolipoprotein B (0.011, 95 % CI: 0.006,0.017), fasting glucose (0.076, 95 % CI: 0.010,0.142), and insulin (3.159, 95 % CI: 1.180,5.138), as well as decreases in the cardioprotective lipids, HDL (-0.015, 95 % CI: 0.023,-0.008) and apolipoprotein A1 (-0.010, 95 % CI: 0.020,-0.000). Lipid and apolipoprotein levels as well as markers of insulin resistance were predominantly altered in children and younger adults, although there was no significant effect modification by age. On- and off-road transportation sectors were most frequently associated with adverse lipid biomarker effects. The joint effects of mean annual PM_2.5, O₃, NO₂, and SO₂ exposures were associated with worsening cardiometabolic markers. Further research is required to better understand the mechanisms by which specific air pollution components disrupt metabolic pathways.