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

OBJECTIVE: 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. METHODS: 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. RESULTS: Of the 3017 participants (mean age 38 years), 1453 (48%) were women. The average PM(2.5) exposure was 51 µg/m(3) (range 13–85) for men, and 61 µg/m(3) (range 40–120) for women, while the average BC was 4 µg/m(3) (range 3–7) for men and 8 µg/m(3) (range 3–22) for women. A 10 μg/m(3) 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 μg/m(3) PM(2.5); 0.5%, 95% CI 0.1, 0.8, per 2 μg/m(3) BC). CONCLUSIONS: 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.