Fine particulate matter constituents and sub-clinical outcomes of cardiovascular diseases: A multi-center study in China

Limited evidence is available on the associations of long-term exposure to various fine particulate matter (PM2.5) constituents with sub-clinical outcomes of cardiovascular disease (CVD) in China. We aimed to explore the associations of PM2.5 and its constituents with blood pressure (BP), fasting glucose, and cardiac electrophysiological (ECG) properties based on a national survey of 5852 Chinese adults, who participated in the Sub-Clinical Outcome of Polluted Air study, from July 2017 to March 2019. Annual residential exposure to PM2.5 and its constituents of each subject was predicted by a satellite-based mode. We assessed the associations between five main constituents [organic matter (OM), black carbon (BC), sulfate (SO42−), nitrate (NO3−), ammonium (NH4+)] of PM2.5 and systolic BP (SBP), diastolic BP (DBP), fasting glucose, and ECG measurements (PR, QRS, QT, and QTc interval) using multivariable linear regression models. Long-term PM2.5 exposure was significantly associated with increased levels of fasting glucose, DBP, and ECG measurements. An IQR increase in OM (8.2 μg/m3) showed considerably stronger associations with an elevated fasting glucose of 0.39 mmol/L (95%CI confidence interval: 0.28, 0.49) compared with other PM2.5 constituents. Meanwhile, an IQR increase in NO3−, NH4+ and OM had stronger associations with DBP and ECG parameters compared with BC and SO42−. This nationwide multi-center study in China indicated that some constituents (i.e., OM, NO3−, and NH4+) might be mainly responsible for the association of PM2.5 with sub-clinical outcomes of CVD including BP, fasting glucose, and ECG measurements.