Characterizing Ambient Air Pollution Exposures, and the Biological Mechanisms Mediating the Associated Health Effects among Street Vendors in Accra (Biommaps Study): A Study Protocol

Abstract

Street vendors dominate the urban landscape of developing country cities with documented reports of high levels of air pollution (AP) exposures among these workers owing to the congested traffic in these cities. There is, however, limited evidence on the adverse health experiences of street vendors. Also, the exact biological mechanisms of respiratory and cardiovascular injury from exposure to AP have not been fully elucidated. In order to better understand the adverse health effects of AP exposure so as to tailor treatment and preventive strategies, it is important to establish the biological pathways. Genome-wide association studies have the capability of identifying novel genes and genetic polymorphisms in AP response phenotypes and consequently provide insight into the biological mechanisms underlying air pollution health effects. It is against this background that our aim is to characterize air pollution levels and the associated adverse health effects among street vendors in Accra, as well as elucidating the biological mechanisms mediating the associated adverse health effects. Longitudinal study of five-year duration will be conducted. Six hundred (600) street vendors permanently working at six traffic hotspots and 600 teachers teaching in schools in three affluent neighborhoods will be recruited and followed up every three months throughout the study period. Personal AP monitoring among 200 selected street vendors and 200 selected teachers will be undertaken once a week. Spirometric (FEV1, FVC and FEV1%), exhaled nitric oxide (eNO) and BP measurements will be taken at baseline and during each follow-up visit to assess lung function, endothelial function and onset of hypertension among the participants. Blood and sputum samples will be collected at baseline and every follow-up visit to measure levels of immunological markers of oxidative stress and inflammation, lipids, and to identify novel genes, explore polymorphisms and undertake gene expression.