653 Crohn's Disease Mortality and Ambient Air Pollution in New York City

Abstract

INTRODUCTION: Recent years have seen an increase in the prevalence of Crohn's Disease (CD), along with drastically rising modernization at a pace not seen before, and an accompanying decline in air quality. Air pollution has been shown to affect epithelial cell function and modulate immune responses, as well as change the composition of enteric microbiota. In epidemiologic studies, ambient air pollution has demonstrated a weakly positive relationship with incident CD cases, along with CD hospitalizations. However, to date, there are no data on the associated risk of CD-related death in relation to air pollution exposure. METHODS: We conducted an ecologic study comparing the number of CD deaths of individuals residing in given zip codes, with the level of air pollution from NO, NO2, SO2, and fine particulate matter (PM2.5). Cases consisted of any patients with CD mentioned on their death certificate who died in New York City between 1993-2010. Zip code was assigned by patient residence. Air pollution was measured by the New York Community Air Survey. We conducted Pearson correlations, and a Poisson regression with robust standard errors. Each component of pollution was modeled separately. RESULTS: There was a higher risk of CD-related death among individuals living in zip codes with higher levels of SO2 (IRR 1.16, Cl 95% 1.06-1.27). Zip codes with higher percentage of Black and Latino residents were associated with lower rates of CD-related death in the SO2 model (IRR .58 Cl 95% .34-.98, IRR .14 Cl 95% .06-.33). There was no significant association of either population density or area-based income with the CD-related death rate. NO, NO2, and PM2.5 were not associated with a higher risk of death. CONCLUSION: In New York City from 1993-2010, CD death rates were higher among individuals from neighborhoods with higher levels of SO2, and lower among those from neighborhoods with predominately Black or Latino residents. CD death rates were not associated with levels of NO, NO2, or PM2.5. These findings raise an important and timely public health issue regarding exposure of CD patients to environmental SO2, and suggest that this area of Crohn's Disease research needs further exploration.