Cooking fuel choices and garbage burning practices as determinants of birth weight: a cross-sectional study in Accra, Ghana

BACKGROUND Effect of indoor air pollution (IAP) on birth weight remains largely unexplored but yet purported as the most important environmental exposure for pregnant women in developing countries due to the effects of second-hand smoke. We investigated the associations between the determinants of indoor air quality in households and birth weight. METHODS A cross-sectional study of 592 mothers and their newborns using postnatal services at the Korle Bu Teaching Hospital located in Accra, Ghana was conducted in 2010 to collect information on characteristics of indoor environment and other potential determinants of fetal growth. Birth weight was recorded from hospital records. RESULTS Household cooking fuel choices and garbage burning practices were determinants of birth weight. Multivariate linear regression analysis adjusting for age, social class, marital status and gravidity of mothers, and sex of neonate resulted in a 243 g (95% CI: 496, 11) and 178g (95% CI: 421, 65) reduction in birth weight for use of charcoal, and garbage burning respectively compared with use of LPG only. The estimated reductions in birth weight was not statistically significant. Applying the ordinal scale exposure parameter nonetheless revealed a significant exposure-response relationship between maternal exposures from charcoal use and garbage burning, and birth weight. Generalized linear models adjusting for confounders resulted in a 41% (risk ratio [RR] = 1.41; 95% CI: 0.62, 3.23) and 195% (RR=2.95; 95% CI: 1.10, 7.92) increase in the risk of low birth weight (LBW) for use of charcoal, and garbage burning respectively compared with use of LPG only. A combination of charcoal use and household garbage burning during pregnancy on fetal growth resulted in a 429 g (95% CI: 259, 599) reduction in birth weight and 316% (RR=4.16; 95% CI: 2.02, 8.59) excess risk of LBW. Sensitivity analysis performed by restricting the analysis to term births produced similar results. CONCLUSIONS Maternal use of charcoal as a cooking fuel during pregnancy and burning of garbage at home are strong determinants of average fetal growth and risk of LBW. Efforts to reduce maternal exposures to IAP are thus important to improve birth outcomes.