Personal exposure to particulate air pollution and vascular damage in peri-urban South India

Air pollution is a leading preventable risk factor for cardiovascular diseases. Previous studies mostly relied on concentrations at residence, which might not represent personal exposure. Personal air pollution exposure has a greater variability compared with levels of ambient air pollution, facilitating evaluation of exposure-response functions and vascular pathophysiology. We aimed to evaluate the association between predicted annual personal exposure to PM_2.5 and black carbon (BC) and three vascular damage markers in peri-urban South India.

We analyzed the third wave of the APCAPS cohort (2010-2012), which recruited participants from 28 villages. We used predicted personal exposure to PM_2.5 and BC derived from 610 participant-days of 24 h average gravimetric PM_2.5 and BC measurements and predictors related to usual time-activity. Outcomes included carotid intima-media thickness (CIMT), carotid-femoral pulse wave velocity (cf-PWV) and augmentation index (AIx). We fit linear mixed models, adjusting for potential confounders and accounting for the clustered data structure. We evaluated nonlinear associations using generalized additive mixed models.

Of the 3017 participants (mean age 38 years), 1453 (48%) were women. The average PM_2.5 exposure was 51 µg/m³ (range 13-85) for men, and 61 µg/m³ (range 40-120) for women, while the average BC was 4 µg/m³ (range 3-7) for men and 8 µg/m³ (range 3-22) for women. A 10 microg/m³ increase of PM_2.5 was positively associated with CIMT (0.026 mm, 95% CI 0.014, 0.037), cf-PWV (0.069 m/s, 95% CI 0.008, 0.131) and AIx (0.8%, 95% CI 0.3, 1.3) among men. The exposure-response function for PM_2.5 and AIx among men showed non-linearity, particularly within the exposure range dominated by tobacco smoking and occupational exposures. Both PM_2.5 and BC were positively associated with AIx among women (0.6%, 95% CI 0.2, 1.0, per 10 microg/m³ PM_2.5; 0.5%, 95% CI 0.1, 0.8, per 2 microg/m³ BC).

Personal exposure to particulate matter was associated with vascular damage in a peri-urban population in South India. Personal exposure to particulate matter appears to have gender-specific effects on the type of vascular damage, potentially reflecting differences in sources of personal exposure by gender.