Diabetes and liver cancer risk: A stronger effect in Whites than Blacks?

BACKGROUND: Both diabetes and liver cancer are overrepresented among African Americans, but limited information is available on the interrelationship of these two diseases among African Americans. We examined the association of diabetes with the incidence of liver cancer and whether this varied by participant self-reported race/ethnicity. METHODS: Using the Southern Community Cohort Study, we conducted a cancer follow up (2002-2016) of a cohort of mostly low-income participants aged 40-79 with diabetes (n = 15,879) and without diabetes (n = 59,077) at study baseline. Cox regression was used to compute Hazard Ratios (HR) and 95% CIs for the risk of incident liver cancer. RESULTS: With 790,132 person years of follow up, 320 incident cases of liver cancer were identified. In analyses controlling for age, sex, race, BMI, current and former smoking, total alcohol consumption, family history of liver cancer, any hepatitis infection, hyperlipidemia and socioeconomic factors, the association between diabetes and risk of liver cancer differed significantly (pinteraction = 0.0001) between participants identifying as Black/African American (AA) or White/European American (EA). Diabetes was associated with 5.3-fold increased cancer risk among EAs (HR 5.4, 95% CI 3.2-9.3) vs an 80% increase (HR 1.8, 95% CI 1.3-2.5) among AAs. Furthermore, controlling for diabetes greatly attenuated the higher risk of liver cancer among AAs; indeed, while the cancer risk among those without diabetes was twice as high among AAs than EAs (HR = 2.0, 95% CI = 1.4-2.9), no excess in AAs was observed among those with diabetes (HR = 0.7, 95% CI = 0.4-1.1). CONCLUSION: While liver cancer risk in general is greater in AAs than EAs and diabetes increases this risk in both racial/ethnic groups, diabetes appears to impact liver cancer to a much greater extent among EAs. The findings raise the possibility of racially different mechanisms and impacts of diabetes on this often fatal cancer among AAs and EAs.

Racial Differences in Hepatocellular Carcinoma Incidence and Risk Factors among a Low Socioeconomic Population.

The purpose of this study was to examine differences in risk factors associated with hepatocellular carcinoma (HCC) among White and African Americans from low socioeconomic backgrounds in the Southern Community Cohort Study (SCCS). The SCCS is a prospective cohort study with participants from the southeastern US. HCC incidence rates were calculated. Multivariable Cox regression was used to calculate HCC-adjusted hazard ratios (aHR) associated with known baseline HCC risk factors for White and African Americans, separately. There were 294 incident HCC. The incidence rate ratio for HCC was higher (IRR = 1.4, 95%CI: 1.1-1.9) in African Americans compared to White Americans. White Americans saw a stronger association between self-reported hepatitis C virus (aHR = 19.24, 95%CI: 10.58-35.00) and diabetes (aHR = 3.55, 95%CI: 1.96-6.43) for the development of HCC compared to African Americans (aHR = 7.73, 95%CI: 5.71-10.47 and aHR = 1.48, 95%CI: 1.06-2.06, respectively) even though the prevalence of these risk factors was similar between races. Smoking (aHR = 2.91, 95%CI: 1.87-4.52) and heavy alcohol consumption (aHR = 1.59, 95%CI: 1.19-2.11) were significantly associated with HCC risk among African Americans only. In this large prospective cohort, we observed racial differences in HCC incidence and risk factors associated with HCC among White and African Americans.