Abstract A41: Social determinants of hepatocellular carcinoma in Louisiana
Authors: Danos Denise M. , Ferguson Tekeda F. , Simonsen Neal , Leonardi Claudia , Yu Qingzhao , Wu Xiao-Cheng , Scribner Richard 
Published: February 2019

Purpose: Over the past three decades, hepatocellular carcinoma (HCC) is one of the few cancers for which incidence has increased in the United States (U.S.). While chronic infection with hepatitis C virus is a leading risk factor for HCC, other known risks that are more prevalent in the U.S. population, including alcohol abuse, metabolic disease, and obesity, have also contributed to increasing rates. There is growing recognition that social and/or nutritive stress represent exposures that negatively affect individual health. These factors are believed to be socially determined by conditions in an individual's neighborhood environment. We designed a population-based study to identify potential social determinants of the increase in HCC by investigating the association of HCC incidence with neighborhood environments characterized by concentrated disadvantage.

Methods: Data from the Louisiana Tumor Registry, a participant of the National Cancer Institute's Surveillance and Epidemiology End Results (SEER) program, were used in the analysis of primary HCC diagnosed from 2008 to 2012. Cases were geocoded to census tract of residence by address at the time of diagnosis. Average annual incidence rates were calculated for age, race, and sex groups within census tracts based on 2010 US Census data. Neighborhood concentrated disadvantage index (CDI) for each census tract was calculated in accordance with the PhenX Toolkit protocol. We excluded census tracts outside of metropolitan statistical areas, as well as any tract with less than 500 people or zero households, from the analyses. Multilevel log-binomial models were used to evaluate neighborhood variation and quantify the degree of association of CDI with HCC incidence.

Results: The study included 1,407 cases of HCC diagnosed from 2008 to 2012. Univariate analyses indicated significantly greater incidence of HCC among males (p&lt;0.0001) and among African Americans when compared to whites (p&lt;0.0001). Generally, incidence increased with age, with the exception of a peak observed at age 50-64 among black males. In multilevel models controlling for age, race, and gender, we observed significant variation in HCC incidence among parishes and among census tracts, or neighborhoods, within parishes. To explain neighborhood variation in HCC, a measure of neighborhood concentrated disadvantage (CDI) was included in the analysis. Neighborhood CDI partially explained tract-level variation and was positively associated with the incidence of HCC. A one unit increase in CDI was associated with 23% increase in HCC risk [Risk Ratio (RR)=1.23; 95% CI (1.15,1.31)]. There was a notable difference in the distribution of CDI for the study population by race, with African Americans disproportionately represented in the most disadvantaged areas. Thus, adjusting for contextual effects of an individual's neighborhood reduced the observed racial disparities in HCC.

Discussion/Conclusion: We have found neighborhood concentrated disadvantage to be a significant risk factor for the development of HCC. We also determined that differential exposure to neighborhoods of concentrated disadvantage contributed to observed racial disparities in HCC in Louisiana. Our results suggest that increasing rates of HCC, and existing racial disparities in the disease, are partially driven by social contexts of adverse living environments.

Citation Format: Denise M. Danos, Tekeda F. Ferguson, Neal Simonsen, Claudia Leonardi, Qingzhao Yu, Xiao-Cheng Wu, Richard Scribner. Social determinants of hepatocellular carcinoma in Louisiana [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr A41.