THE ROLE OF DEVELOPMENTAL TOXICANTS AND SOCIO-ECONOMIC STATUS ON CONGENITAL HEART DISEASE IN URBAN AND RURAL ALBERTA

Abstract

Abstract BACKGROUND Evidence is emerging suggesting associations between environmental pollutants, socio-economic status (SES) and congenital heart disease (CHD); however, it is still inconclusive. Furthermore, it has been documented in environmental injustice studies that people with low socio-economic status are disproportionately vulnerable to environmental hazards and therefore are victims of a double jeopardy. OBJECTIVES We sought to explore the effect of exposure to groups of developmental toxicants (DTs) and SES on CHD development in urban and rural Alberta. DESIGN/METHODS We identified 2,413 CHD cases and postal codes (PC) from echocardiographic databases (2003–2010). We used previously defined groups of DTs comprised of: 1- organics and gases, 2-organics and 3-heavy metals. Exposure was assigned to each PC as the sum of the product of multiplying amounts of DTs (tonnes) emitted from any industrial facility within 10 km radius during the whole study period, by the inverse distance from the facility to the centroid of the PC. Exposures were categorized into deciles from 1(lowest) to 10 (highest) for group 1 DTs and tertiles (1=lowest to 3 =highest), for groups 2 and 3 DTs and the SES index. Poisson regression models were used to calculate risk ratios and 95% CI, adjusted for SES index or DTs and traffic-related surrogates (NO2, PM2.5). RESULTS Adjusted Effect of DT Exposure: Group 1 DT showed increased risk in urban and rural regions in the 10th decile of exposure, aRR=1.85(1.5, 2.3) and 2.67(1.04, 6.8, respectively). Group 2 DT risk was increased only in urban 3rd tertile, RR=1.45(1.3, 1.6). Group 3 DTs were associated with an increased risk in urban and rural regions in the 3rd tertile of exposure [aRR=1.16(1.04, 1.3), and 2.8(1.14, 7.1, respectively)]. Adjusted Effect of SES: SES was independently associated with an increased risk of CHD in urban lowest tertile, [aRR=1.13(1.0, 1.3)] and rural lowest and middle SES tertile, [aRR=2.9(1.9, 4.8) and 1.6(1.1, 2.6), respectively]. CONCLUSION High exposures to groups of DTs and SES were independently associated with an increased risk of CHD in urban and rural Alberta. This suggests that neighborhood SES in Alberta does not impose a disproportional exposure to DTs. Furthermore, SES had a greater impact in rural compared to urban regions. We would like to explore for interactions between the SES and DT exposures and to determine if there is environmental injustice in Alberta.