Disparities in the association between air pollution exposure and nonalcoholic fatty liver disease

Authors: Trang VoPham*, Fred Hutchinson Cancer Research Center
Topics: Medical and Health Geography
Keywords: air pollution, liver disease, epidemiology
Session Type: Virtual Paper
Presentation File: No File Uploaded


Background: Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. Particulate matter air pollution <2.5 µm in diameter (PM2.5) is an environmental pollutant forming from combustion sources. Some previous epidemiologic studies have suggested positive associations with NAFLD and potential differential impacts across population subgroups. The objective of this study was to examine the effect of ambient PM2.5 exposure on NAFLD disparities by geography, race/ethnicity, and sex.

Methods: We conducted cross-sectional analyses of hospitalizations (2001-2011) using the U.S. Nationwide Inpatient Sample administrative database. Average annual PM2.5 exposure was estimated using NIS ZIP Codes linked with the Environmental Protection Agency Downscaler Model. We conducted stratified analyses using multilevel logistic regression to calculate odds ratios per 10 µg/m3 increase and 95% confidence intervals adjusted for demographics, clinical conditions, and socioeconomic status.

Results: The analyses included an unweighted average of 2.7 million hospitalizations per year. The association between ambient PM2.5 exposure and odds of NAFLD hospitalizations varied by race/ethnicity and sex (p interaction<0.01), with positive associations among non-Hispanic whites, non-Hispanic blacks, and non-Hispanic Asians or Pacific Islanders. No associations were observed among racial/ethnic categories for Hispanics, non-Hispanic Native Americans, and other. A stronger positive association was observed among women compared to men. There was no evidence of effect modification by region (p interaction>0.05).

Conclusions: The association between ambient PM2.5 air pollution exposure and NAFLD may vary by race/ethnicity and sex. Future research should examine residential exposure and incident NAFLD cases.

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