Effects of an LPG stove intervention on gestational blood pressure: findings from Household Air Pollution Intervention Network randomized controlled trial

Abstract

BACKGROUND AND AIM: Cooking and heating using solid fuels can cause dangerous levels of exposure to household air pollution (HAP). HAPIN is an ongoing randomized controlled trial aimed at assessing the impact of a liquified petroleum gas (LPG) cookstove and fuel intervention on HAP exposure and health among householders in India, Guatemala, Peru and Rwanda that rely chiefly on solid cooking fuels. Given the potential impacts of HAP exposure on cardiovascular outcomes during pregnancy, we seek to characterize the relationship between personal exposures to HAP and gestational blood pressure (GBP) among pregnant women. METHODS: The trial enrolled approximately 800 pregnant women between 9 and 20 gestational weeks (GW) from each participating country (N=3195) and randomly allocated half to an intervention group that received an LPG stove and fuel throughout the duration of their pregnancy; control group members received no intervention at trial launch. We continuously monitor intervention fidelity and adherence. We assess repeated 24-hour personal exposure to PM2.5/BC/CO and gestational systolic blood pressure (SBP) and diastolic blood pressure (DBP) at on enrollment and at two follow-up visits at 24-28 GW and 32-36 GW. Effects of the intervention on gestational SBP and DBP will be reported using both an intention-to-treat (ITT) and exposure-response analysis. RESULTS:Preliminary data from stove use monitoring shows nearly exclusive use of the intervention during the follow-up period. Preliminary data from personal exposure monitoring shows a substantial exposure contrast between intervention and control arms, with PM2.5 below the WHO interim target-1 level of 35 µg/m3, compared with the pre-intervention median of 84.5 µg/m3. Analysis of intervention effects on SBP and DBP are being finalized and will be presented. CONCLUSIONS:This study will add new evidence to the field of HAP exposure and BP among women during pregnancy, a critical window for health over the life course in both mother and child. KEYWORDS: Household Air Pollution, Gestational Blood Pressure, Randomized Controlled Trial, Liquified Petroleum Gas