Associations of PM2.5 Exposure with Blood Pressure among Pregnant Women in Rural India: Evidence from the HAPIN Trial

Abstract

Background: The Household Air Pollution Intervention Network (HAPIN) is an ongoing multi-center randomized controlled trial aimed at assessing the impact of a liquified petroleum gas (LPG) cooking stove and fuel intervention on health. Given the potential impacts of household air pollution (HAP) exposure from solid fuel burning on cardiovascular outcomes on pregnancy, we sought to determine whether exposure to PM2.5 (as an indicator pollutant of HAP) was associated with gestational blood pressure (GBP) among 800 adult women in India, one of the HAPIN trial centers. Methods: Mixed-effects models were used to examine the association between PM2.5 exposure and BP, determined by repeated 24-hour personal exposure and GBP monitoring at baseline (< 20 gestational weeks [GW]), second (24-28 GW) and third (32-36 GW) follow-up visits. Preliminary data from 799 mothers were included in regression analysis. Among these, 220 completed two measurements and 527 completed three measurements. Results: We found a significant positive association between nephelometric PM2.5 exposure and systolic blood pressure (SBP): on average, each IQR µg/m3 increase in PM2.5 exposure was associated with 0.05 mmHg higher SBP [0.002, 0.1]. A non-significant positive relationship was observed for diastolic blood pressure (DBP). Additionally, we observed a significant difference in SBP and DBP between the two study sites - Villupuram and Nagapattinam. Conclusion: This study added new evidence regarding the relationship between HAP exposure and BP among Indian women during pregnancy, a critical window for both mother and child’s life-course health. Preliminary results of this longitudinal study suggest that HAP from solid fuel burning is associated with higher blood pressure, particularly SBP, in pregnant women over the second and third trimester, controlling for maternal age, BMI, and gestational age.