Liquefied Petroleum Gas or Biomass for Cooking and Effects on Blood Pressure: Results from the Household Air Pollution Intervention Network (HAPIN) Trial.

Background: Exposure to household air pollution from burning coal and biomass for cooking is associated with higher blood pressure and other adverse indicators of cardiovascular disease, the leading cause of death worldwide. Evidence demonstrating that switching from biomass to liquefied petroleum gas (LPG) will reduce blood pressure is limited. Methods: As part of a larger trial of 3200 households, we conducted a randomized trial of 342 women aged 40 to 79 years who lived in households using biomass for cooking in rural areas of Guatemala, India, Peru, and Rwanda to assess the effects of a free LPG stove and fuel intervention. Systolic blood pressure (one of four primary outcomes) was measured once prior to randomization and up to five times after randomization over 18 months. Results: A total of 418 participants were randomized (n=209 to intervention, and n=209 to control). Mean (standard deviation) systolic blood pressure at baseline was 112.7 (14.9) mmHg and 112.6 (14.7) mmHg in intervention and control participants, respectively. Adherence within the intervention arm was high. Among the 342 participants with a valid baseline and at least one valid post-randomization blood pressure measurement, mean (SD) post-randomization average systolic blood pressure was 111.5 (13.2) mmHg in the intervention arm and 111.9 (12.5) mmHg in the control arm, with an adjusted mean of difference of -0.56 mmHg (95% confidence interval, -2.19 to 1.07, p-value = 0.50). Conclusions: We did not observe evidence that an 18-month LPG stove and fuel intervention reduced blood pressure in women.