Abstract PR9: Diabetes and racial/ethnic differences in hepatocellular carcinoma risk: The Multiethnic Cohort
Authors: Setiawan Veronica Wendy , Hernandez Brenda , Stram Daniel , Wilkens Lynne , Marchand Loic Le , Henderson Brian E. 
Published: May 2015

Abstract
Background: Hepatocellular carcinoma (HCC) incidence has tripled in the US over the past three decades. Diabetes has been suggested as an emerging risk factor for HCC and its increasing prevalence may contribute to the rising incidence of HCC. Data from prospective studies on the relationship between diabetes and HCC in multiethnic populations are scarce. Here we examined whether the association between diabetes and HCC risk differs across racial/ethnic groups, and whether the association is modified by known HCC risk factors.
Methods: We conducted a prospective analysis of 169,479 African-American, Native Hawaiian, Japanese-American, Latino and white men and women who were recruited into the Multiethnic Cohort (MEC) Study between 1993 and 1996. During a median follow-up period of 15.7 years, a total of 506 incident HCC cases (59 whites, 81 African Americans, 33 Hawaiians, 158 Japanese, and 175 Latinos) were identified among the cohort participants. Data on known and suspected risk factors were obtained from baseline questionnaire. Serologic testing for hepatitis B (HBV) and C (HCV) infection was performed on a subset of cohort subjects (233 cases and 460 non cases). Cox proportional hazards models stratified by sex and adjusted for age, alcohol drinking, body mass index (BMI in kg/m2) and cigarette smoking were used to calculate relative risks (RRs) and 95% confidence intervals (CIs) for HCC associated with diabetes for each ethnic group. The population attributable risk percent associated with diabetes was also calculated for each ethnic group.
Results: Incidence rates of HCC markedly differed across race/ethnic groups; the age-adjusted RRs for HCC (vs. whites) were 2.77 (95% CI: 2.03, 3.78) for Latinos, 2.48 (95% CI: 1.59, 3.86) for Native Hawaiians, 2.16 (95% CI: 1.52, 3.07) for African Americans, and 2.07 (95% CI: 1.51, 2.38) for Japanese. The age- and sex-adjusted prevalence of diabetes at baseline also varied across ethnic groups: 16% in Hawaiians, 15% in Latinos, 15% in African Americans, 10% in Japanese, and 6% whites (P&lt;0.0001). Diabetes was strongly associated with HCC risk in all ethnic groups (P-heterogeneity=0.40); the RR was 3.33 (95% CI: 2.39, 4.63) in Latinos, 2.54 (95% CI: 1.13, 5.70) in Hawaiians, 2.33 (95% CI: 1.60, 3.40) in Japanese, 2.02 (95% CI: 1.17, 3.49) in African Americans, and 2.17 (95% CI: 0.95, 4.93) in whites. BMI, smoking status, and alcohol intake did not modify the diabetes-HCC association (P interaction ≥ 0.19). Within a subset of cohort participants with available HBV and HCV serologic data, diabetes was not associated with infection status (P ≥ 0.07). We estimated that 26% of HCC cases in Latinos, 20% in Hawaiians, 13% in African Americans, 12% in Japanese, and 6% in whites were attributed to diabetes.
Conclusions: In the MEC, Latinos were at the highest risk of developing HCC, followed by Native Hawaiians, African Americans, Japanese and whites. We showed that diabetes is a strong risk factor for HCC in all ethnic groups and that the inter-ethnic differences in the prevalence of diabetes was consistent with the pattern of HCC incidence observed across ethnicities. Finally, we showed that eliminating diabetes could potentially reduce HCC incidence in all racial/ethnic groups, with the largest potential for reduction in Latinos.
This abstract is also presented as Poster C91.
Citation Format: Veronica Wendy Setiawan, Brenda Hernandez, Daniel Stram, Lynne Wilkens, Loic Le Marchand, Brian E. Henderson. Diabetes and racial/ethnic differences in hepatocellular carcinoma risk: The Multiethnic Cohort. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr PR9. doi:10.1158/1538-7755.DISP13-PR9