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Association between overall environmental quality and lung cancer survival
Citation:
Jagai, J., A. Patel, C. Gray, K. Rappazzo, M. Jimenez, S. Deflorio-Barker, AND D. Lobdell. Association between overall environmental quality and lung cancer survival. Society for Epidemiologic Research, Seattle, Washington, June 20 - 23, 2017.
Impact/Purpose:
The purpose of this study was to examine the impact of cumulative environmental exposures on lung cancer survival. This study utilized the Environmental Quality Index
Description:
Lung cancer remains one of the most prevalent and lethal cancers in the United States. Individual environmental exposures have been associated with lung cancer incidence. However, the impact of cumulative environmental exposures on survival is not well understood. To address this gap, we estimated county level environmental quality in the United States using U.S. Environmental Protection Agency’s (USEPA) Environmental Quality Index (EQI). The EQI captures exposure to over 200 environmental factors across five environmental domains (air, water, land, sociodemographic, and built) for the years 2000-2005. For persons diagnosed with lung cancer from 2000-2005 (n=272,371), individual level data on survival time (through Dec. 31, 2013) and co-variates (age, marital status, sex, histology, stage, race, surgery, radiation) from the Surveillance, Epidemiology, and End Results Program (SEER) were linked to the EQI based on place of residence. We modeled the EQI and domain-specific indices as quartiles (Q; Q4 worst environment) using Cox Proportional Hazard models to estimate hazard ratios (HR) and 95% confidence intervals. We adjusted for individual-level covariates and stratified by stage at diagnosis (local, regional, distant) and rural-urban status. Prior to stratification, overall EQI and individual domains showed mostly null or slight positive or negative associations comparing highest to lowest index quartile (EQIQ4: HR=0.92(0.89,0.95). Post stratification, we observed positive associations for the individual domains across different strata (e.g. Non-Metro Urban, Local Stage AirQ4: HR=1.21(1.11, 1.33); Metro Urban, Local Stage SociodemQ4: HR=1.08(1.03,1.13)). Most positive associations were seen in urban areas and at the localized cancer stage. The results suggest association between poor environmental quality and decreased lung cancer survival, with potential variation by rural-urban status and stage at diagnosis. This abstract does not necessarily reflect EPA policy.