Work as a street vendor, associated traffic-related air pollution exposures and risk of adverse pregnancy outcomes in Accra, Ghana

摘要

Background: Street vending, a dominant occupation in urban areas of developing countries exposes the vendors to several environmental pollutants. We investigated whether work as street vendor impairs foetal growth and shortens gestational duration, and evaluated to what extent exposure to traffic-related air pollution is responsible for these adverse effects. Methods: A cross-sectional study was conducted among mothers and their newborns accessing postnatal services at the Korle Bu Teaching Hospital in Accra, Ghana in 2010, focusing on 105 street vendors and a reference group of 281 mothers. We categorized exposure to traffic-related air pollution on the basis of street vending activity patterns and traffic density in the working area. Results: Multivariate linear regression analysis adjusting for age, social class, marital status and gravidity of mothers, sex of neonate, and indoor air pollution, indicated a 177 g (95% CI: 324,31) reduction in birth weight among street vendors. Sensitivity analysis performed by restricting the analysis to term births showed further reductions in birth weight. Generalized linear models adjusting for confounders indicated a 35% (risk ratio (RR) = 1.35; 95% CI: 0.87, 2.12) increased risk of LBW, albeit statistically not significant. LBW risk increased in the sensitivity analysis but was also not statistically significant. The risk of PTB was not associated with street vending (RR= 1.03; 95% CI: 0.67,1.58). The exposure-response relations observed were not consistent. Moderate activity patterns and high traffic density jointly was associated with a statistically significant 84% (RR= 1.84; 95% CI: 1.05,3.24) increased risk of LBW. Conclusion: Street vending during pregnancy is a determinant of average foetal growth and risk of LBW. More research is required to further quantify their effects on pregnancy outcomes and safeguard maternal and perinatal health in developing countries.