Association between modelled estimates of ambient PM2.5 concentrations and biomarkers of early vascular aging in the PURSE-HIS cohort, Tamil Nadu, India

Abstract

Introduction: Long-term exposure to ambient fine particulate matter (≤2.5 µm in diameter, PM2.5) has been associated with cardiovascular mortality and disease; however, little is known about its relationship with early vascular aging (EVA), an intermediate step on the path to overt illness. Here we assess the association of PM2.5 with EVA in the Population Study of Urban Semi-urban Rural Endovascular Disease and Holistic Intervention Study (PURSE-HIS) cohort. Methods: The cohort included 8080 randomly selected participants (mean age 42 years; 56% women) living in a ~80 km2 region of Tamil Nadu, India. We used PM2.5 estimates developed for the Global Burden of Disease (2010), which combined satellite-based estimates, chemical transport model simulations, and ground measurements to produce estimates of annual average PM2.5 concentrations at ~10 x 10 km resolution. EVA was assessed by blood pressure (systolic, SBP; diastolic, DBP), central pulse pressure (cPP), pulse wave velocity (PWV) and flow mediated dilatation (FMD). Multivariable regression models controlling for age, BMI, cooking fuel, energy intake, physical activity, sex, smoking, socioeconomic status and stress were developed to assess the relationship between PM2.5 and measures of EVA. Results: Annual average PM2.5 concentrations ranged from 18 to 35 µg/m3, with an interquartile range (IQR) of 3 µg/m3. In multivariate models, an IQR increase in PM2.5 concentration was associated with increases in SBP (5.3 mmHg [95%CI: 4.7, 6.0]), DBP (2.0 mmHg [95%CI: 1.6, 2.4]), and cPP (3.5 mmHg [95%CI: 3.1, 4.0]), and a decrease in FMD (0.8 [95%CI: 0.5, 1.0]). PWV had a positive, non-significant association with PM2.5 (0.05 m/s [95%CI: -0.02, 0.12]). Conclusions: Our findings demonstrate an independent association of EVA with PM2.5 exposure. More detailed exposure assessments and longitudinal follow-up are needed to better understand the relationship of PM2.5 exposure and EVA.