Household Air Pollution Exposure and Childhood Blood Pressure: Evidence from GRAPHS

Abstract

Background Household air pollution (HAP) exposure results in ~2.8 million premature deaths annually, largely due to cardiovascular disease. The effects of early life HAP exposure, or a clean cookstove intervention, on child blood pressure (BP), are unknown.MethodsThe Ghana Randomized Air Pollution and Heath Study (GRAPHS) randomized pregnant, non-smoking women to one of two cookstove interventions (liquefied petroleum gas, LPG, or improved biomass cookstove) or control, through the index child’s first birthday. Personal HAP exposures [fine particulate matter (PM2.5) and carbon monoxide (CO)] were repeatedly measured prenatally and through child age 4 years. At child age four and five years, we measured resting systolic BP (SBP) and diastolic BP (DBP) (Dinamap Pro 100) per protocol in N=631 children. We employed generalized estimating equations to examine associations between early life CO and PM2.5 and SBP and DBP, following adjustment for maternal age, child sex, BMI, ethnicity and second-hand tobacco smoke exposure. We then employed multivariable linear regression to determine associations between cookstove intervention arm and SBP and DBP. Sex-specific effects were explored.ResultsMedian PM2.5 and CO exposures were 67.5μg/m3 (IQR=42.3-103.6) and 0.87ppm (IQR=0.49-1.41) respectively. Higher early life PM2.5 and CO exposures were independently associated with higher SBP [(PM2.5: 0.24mmHg (0.12-0.35)] per 10μg/m3 increase in PM2.5; CO: 0.59 mmHg (95% CI 0.07-1.12) per 1ppm increase in CO]. Children born to mothers randomized to the LPG arm had lower SBP (-1.62mmHg, 95% CI -3.34, 0.09, p=0.06) and lower DBP (-1.63mmHg, 95% CI -3.13, -0.12, p=0.03), compared to control. Girls were more responsive to the LPG intervention (Girls SBP: -2.73mmHg, 95% CI -5.12, -0.34 vs Boys: SBP: -0.36mmHg, 95% CI -2.85, 2.13).Conclusion Early life HAP exposure is associated with increased SBP in early childhood and a clean-fuel cookstove intervention may ameliorate this effect, particularly amongst girls.