Race/ethnicity and sex differences in the association between area-level arsenic exposure concentration and hepatocellular carcinoma (HCC) incidence rates in Texas. An ecological study.

Texas has the highest rates of hepatocellular carcinoma (HCC) in the United States. Exposure to toxicants may play a role in liver disease. Several mechanisms of arsenic carcinogenesis have been proposed, however, the evidence in human populations is limited to associations between HCC and ingestion of arsenic-contaminated drinking water. Through an ecological study, we examined associations between ambient arsenic and HCC incidence rates. Primary outcome was HCC incidence rates based on Texas Cancer Registry (TCR) data. Primary exposure of interest was the simulated census-tract level estimate of arsenic exposure concentration (EC) from the U.S. Environmental Protection Agency 2011 National Air Toxics Assessment (NATA). We analyzed the association between the arsenic EC and HCC using the negative binomial Poisson regression model separately for six study groups that were based on race/ethnicity and sex. We adjusted the main analyses for selected characteristics. Texas has 5265 census tracts and TCR reported 18,235 new ≥20 years old HCC diagnoses between 2007 and 2015. We observed significant differences along racial-ethnic and sex groups while accounting for socioeconomic deprivation, urban/rural residency, and senior residents' health insurance status. Census tracts with the highest arsenic EC had elevated rates of HCC among NH black men (Quintile 5 vs. Quintile 1: IRR = 2.18, 95% CI: 1.66–2.86), NH black women (Quintile 5 vs. Quintile 1: IRR = 1.72, 95% CI: 1.33–2.22) and NH white men (Quintile 5 vs. Quintile 1: IRR = 1.38, 95% CI: 1.24–1.54). The associations in the remaining study groups were either inconsistent or attenuated. Our finding suggests a potential inhalation pathway for the Arsenic-HCC association; however, the ecological nature of our study precludes the interpretation of a causal link between exposure to aerial arsenic and HCC. This finding needs to be further examined in cohort studies. • Arsenic in the air may contribute to increase in liver cancer diagnosis. • Neighborhood concentration of arsenic in air varies across racial-ethnic groups. • Neighborhoods with highest arsenic concentration had elevated rates of HCC. • Disparity along racial-ethnic and sex lines for the arsenic-HCC association. • A potential inhalation pathway for the Arsenic-HCC association. [ABSTRACT FROM AUTHOR]

Copyright of Environmental Research is the property of Academic Press Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)