Disparities in exposure to traffic-related pollution sources by self-identified and ancestral Hispanic descent in participants of the USC Children's Health Study

Significant evidence has accrued that air pollution negatively impacts respiratory health and other health outcomes. The USC Children's Health Study has also demonstrated a link between increasing levels of air pollution, at both regional and local levels, and reductions in lung development in children. Within Los Angeles and other large urban cities, studies have investigated whether air pollution exposure differs by ethnicity. Preliminary results from these studies suggest that certain ethnic groups, such as Hispanics, may be exposed to higher levels of air pollution compared to non-Hispanics. We aim to further determine whether a disparity exists in local air pollution exposure between Hispanic white (HW) and non-Hispanic white (NHW) children of Southern California. Among Hispanic white children, we also intend to test whether children with a higher percentage of Native American are more exposed to local air pollution sources as well.;From the Children's Health Study cohort, we identified 4,279 NHW and 4,138 HW children with sufficient data to calculate local pollution exposure levels. Among this sample, 2,571 NHW and 2,767 HW children had genetic ancestry data available as well. Multiple linear regression and logistic regression were used to test the association between Hispanic-descent and two measures of local air pollution, distance from freeways/major roadways (m) and Caline4 predicted estimates of NOx levels (ppb). Differences between the groups were determined both in the overall sample and within each of the 14 communities at baseline entry into their respective cohorts.;HW children were found to live, on average, 139 m closer to freeways and 55 m closer to major non-freeway roads in the overall sample compared to NHW children (p < 0.0001). Additionally, HW children with 50% or more Native American ancestry (More-NA HW) lived 244 m closer to freeways compared to NHW children (p < 0.0001) and 143 m closer to freeways than Hispanic White children with less than 50% Native American ancestry (Less-NA HW) (p = 0.003). For major non-freeway roads, More-NA HW live 89 m and 44 m closer to a major road compared to HW children and Less-NA HW, respectively. Based on the secondary outcome measure, HW children had an estimated freeway Caline4 estimates that are 13% (95% CI: 8% - 17%) higher than NHW children. The major non-freeway road NOx exposure is also estimated to be 16% (95% CI: 12% - 19%) higher in HW children compared to NHW children. Among children with ancestry data, freeway Caline4 estimates were 20% and 14% higher for More-NA HW compared to NHW children (p < 0.0001) and Less-NA HW (p < 0.0001), respectively. Additionally, major non-freeway road Caline4 estimates were 27% and 14% higher for More-NA HW compared to NHW children (p < 0.0001) and Less-NA HW (p = 0.0001), respectively. Lastly, the odds of HW children being within 500 m of a freeway or 75 m of major non-freeway road is 1.34 (95% CI: 1.18 -- 1.51) and 1.39 (95% CI: 1.21 - 1.58) times that NHW children, respectively. Within HW, the odds of those with more than 50% NA ancestry being within 500 m of a freeway or 75 m of a major non-freeway road is 1.41 (95% CI: 1.12 -- 1.78) and 1.45 (95 CI: 1.10 -- 1.90) times that of those with less than 50% NA ancestry.;These results provide strong evidence that a differences exist in local air pollution exposure between HW and NHW children. With knowledge of this potential difference in exposure levels, we can further investigate whether these discrepancies lead to significant differences in respiratory and other health-related outcomes between the two groups.