Environmental and health inequalities in England (2000-2015)

Background: Environmental factors, including deprivation, account for 23% of global deaths. Deprivation is believed to magnify differences in the exposure levels (exposure differential), and in the population’s susceptibility to develop health outcomes given an exposure (susceptibility differential). We aimed to examine exposure and susceptibility differentials to various environmental exposures, such as PM2.5 and NO2, across England (2000-2015).
Methods: Population-weighted mean concentrations of the studied exposures were assigned to 2011 Lower Super Output Area, LSOA (1,000-3,000 population) and each LSOA was classified in deciles of Index of Multiple Deprivation (IMD), 2015. To assess the exposure differential component, exposure gradients across IMD deciles were investigated. To evaluate the differential susceptibility component, we used sex- and age-specific all-cause mortality. Age-standardized death rates were investigated by exposure levels across IMD deciles. Finally, we regressed mortality rates to exposure levels adjusting for main confounders and stratifying by deprivation decile.
Results: Mean concentration of PM2.5 and NO2 were 14.01µg/m3 and 29.13µg/m3, respectively. Preliminary results show a positive gradient of concentration by IMD decile, suggesting an exposure differential by deprivation. Between 2000 and 2015, there were an average of 488,511 deaths per annum. Of these, ~11% and ~8% occurred in the top most and least deprived IMD deciles, respectively. After fitting basic regression models, our preliminary results show no difference in the effect of PM2.5 and NO2 on all-cause mortality risk by deprivation decile. More sophisticated statistical approaches are currently being explored in order to account for spatial dependency and other confounders that could be creating noise in our data.
Conclusion: This national study provides up to date evidence on the exposure differential by area deprivation in relation to environmental exposures (e.g. PM2.5 and NO2) across England. It also explores the role of deprivation in the mortality effects of these environmental exposures.