Association between personal exposure to household air pollution and gestational blood pressure among women using solid cooking fuels in rural Tamil Nadu, India.

ABSTRACT

BACKGROUND: The Household Air Pollution Intervention Network (HAPIN) trial is an ongoing multi-center randomized controlled trial assessing the impact of a liquified petroleum gas (LPG) cookstove and fuel intervention on health. Given the potential impacts of household air pollution (HAP) exposure from burning solid fuels on cardiovascular health during pregnancy, we sought to determine whether baseline exposures to particulate matter with an aerodynamic diameter ≤2.5 µm (PM2.5), black carbon (BC) and carbon monoxide (CO) were associated with blood pressure among 799 pregnant women in Tamil Nadu, India, one of the HAPIN trial centers. METHODS: Multivariable linear regression models were used to examine the association between 24-h personal exposure to PM2.5/BC/CO and systolic and diastolic blood pressure, controlling for maternal age, body mass index (BMI), mother's education, household wealth, gestational age, and season. At the time of measurement, women were between 9- and 20-weeks of gestation. RESULTS: We found that systolic blood pressure (SBP) and diastolic blood pressure (DBP) were higher in pregnant women exposed to higher levels of HAP, though only the result for CO and DBP reached conventional statistical significance (p < 0.05). We observed a positive association between CO and DBP among the entire study cohort a 1-log µg/m3 increase in CO exposure was associated with 0.36 mmHg higher DBP (95% confidence interval [CI] 0.02 to 0.70). The effect was stronger in pregnant women with higher CO exposures (in the 3rd [≥ 0.9 and < 2.1 ppm] and 4th quartiles [≥ 2.1 and ≤ 46.9 ppm]). We also found that pregnant women with PM2.5 exposures in the highest quartile (≥ 129.9 and ≤ 2100 µg/m3) had a borderline significant association (p = 0.054) with DBP compared to those who had PM2.5 exposures in the lowest quartile (≥ 9.4 and < 47.7 µg/m3). No evidence of association was observed for BC exposure and blood pressure. CONCLUSION: This study contributes to limited evidence regarding the relationship between HAP exposure and blood pressure among women during pregnancy, a critical window for both mother and child's life-course health. Results from this cross-sectional study suggest that exposures to PM2.5 and CO from solid fuel use are associated with higher blood pressure in pregnant women during their first or second trimester.