Household air pollution and blood pressure among adult women participants of the Household Air Pollution Intervention Network Trial: An exposure-response analysis

Background: Exposure to air pollutants, like fine particulate matter (PM_2.5), has been linked to higher blood pressure (BP). Few studies have examined this association in biomass-dependent settings. We seek to determine whether high exposure during a 16 month period was associated with an increase in BP among older adult women over the study period and to determine whether short-term increases in exposure were associated with higher coincident blood pressure. Methods: As part of a randomized controlled trial of a free liquefied petroleum gas cookstove and 18-month fuel supply, we measured BP and personal exposure to PM_2.5, black carbon (BC), and carbon monoxide (CO) on 368 adult women (mean age 52) in four countries (Rwanda, Peru, Guatemala, and India). We considered short- and long-term associations, the latter measured by change in BP and the former in mixed models of repeated measures. Findings: We found an association between short-term exposure and both systolic and diastolic BP. The highest quartile of BC was associated with a 2 mmHg increase compared to the referent group (p = 0.03). We also found a positive association with PM_2.5, where the highest quartile had a 1.6 mmHg increase in SBP versus the referent group (p = 0.05). We found no association with long-term exposure, nor between CO and BP. Interpretation: In settings where HAP dominates air pollution exposure, we found short-term exposure to BC and PM_2.5 associated with increased BP, consistent with past literature. The lack of long-term associations may have been due to insufficient follow-up. Funding: The study is registered with ClinicalTrials.gov (NCT02944682) and funded by the U.S. National Institutes of Health (1UM1HL134590) in collaboration with the Bill & Melinda Gates Foundation (OPP1131279).