Effects of a Liquefied Petroleum Gas Stove Intervention on Gestational Blood Pressure: Intention-to-Treat and Exposure-Response Findings From the HAPIN Trial

Abstract

Background: Approximately 3 to 4 billion people worldwide are exposed to household air pollution, which has been associated with increased blood pressure (BP) in pregnant women in some studies. Methods: We recruited 3195 pregnant women in Guatemala, India, Peru, and Rwanda and randomly assigned them to intervention or control groups. The intervention group received a gas stove and fuel during pregnancy, while the controls continued cooking with solid fuels. We measured BP and personal exposure to PM 2.5 , black carbon and carbon monoxide 3× during gestation. We conducted an intention-to-treat and exposure-response analysis to determine if household air pollution exposure was associated with increased gestational BP. Results: Median 24-hour PM 2.5 dropped from 84 to 24 μg/m 3 after the intervention; black carbon and carbon monoxide decreased similarly. Intention-to-treat analyses showed an increase in systolic BP and diastolic BP in both arms during gestation, as expected, but the increase was greater in intervention group for both systolic BP (0.69 mm Hg [0.03–1.35]; P =0.04) and diastolic BP (0.62 mm Hg [0.05–1.19]; P =0.03). The exposure-response analyses suggested that higher exposures to household air pollution were associated with moderately higher systolic BP and diastolic BP; however, none of these associations reached conventional statistical significance. Conclusions: In intention-to-treat, we found higher gestational BP in the intervention group compared with controls, contrary to expected. In exposure-response analyses, we found a slight increase in BP with higher exposure, but it was not statistically significant. Overall, an intervention with gas stoves did not markedly affect gestational BP.

The Association between Household Air Pollution and Blood Pressure in Obuasi Municipality, Ghana

“…It is equally likely that the so-called 'fuel stacking' practices, as described in previous studies [24][25][26] together with other environmental sources of PM 2.5 such as trash burning may have also increased the exposure levels to PM 2.5 even among households with clean fuels [27,28]. Regarding the association between household air pollution and the categories of blood pressure as defined by the National High Blood Pressure Education Program [29], we found no suggestive statistical relationship between the type of fuel use and any of the stages [20,30]. Our results showed that the risk of an LPG user becoming pre-hypertensive versus having a normal blood pressure was 0.59 (95% CI: 0.31; 0.52, p-value = 0.102).…”

Maps of solid-fuel use and household air pollution

“…Additionally, analysis of total air pollution over the study period suggests that the disease fraction attributable to household air pollution could be decreasing in LMICs, possibly because of a reduction in the prevalence of solid-fuel use. The observation that rising ambient pollution, especially in LMICs, could lessen the health benefits of clean energy adoption is consistent with the results of large randomised controlled trials, [5][6][7][8] which have not consistently shown improved health outcomes when clean fuels are used for cooking.…”

Prenatal Household Air Pollution Exposure and Childhood Blood Pressure in Rural Ghana

“…reported higher SBP and DBP in the LPG intervention arm as compared with control. 63 We now report that a prenatally introduced LPG stove supported through child age 1 year, but with no evidence of continued use at 4 years of age or exposure differential between groups, was associated with a , or 3%, reduction in DBP relative to children whose mothers used a traditional open fire stove throughout pregnancy. In females, the LPG intervention was associated with a , or 4%, reduction in DBP and a , or 2%, reduction in SBP as compared with control.…”