Hepatocellular carcinoma and other liver disease among Greenlanders chronically infected with hepatitis B virus: a population-based study.
BACKGROUND
In Greenland, the prevalence of hepatitis B surface antigen carriers, reflecting chronic hepatitis B virus (HBV) infection, is 5%-10%. However, the incidence of cirrhosis and hepatocellular carcinoma in this population has been reported to be low. We investigated this discrepancy in a large population-based cohort study.


METHODS
In total, 8879 Greenlanders (16% of the population) were recruited for population-based surveys performed from May 5 to July 7, 1987, and from November 1 to November 21, 1998, with follow-up until March 31, 2010. HBV status was based on serological testing, supplemented by data from all available HBV registries in Greenland to determine changes in HBV status over time. Information on morbidity and mortality was obtained from the Patient Discharge Registry, the Cancer Registry, and the Central Registration System. Sex, age, ethnicity, and period-adjusted incidence rate ratios (IRRs) were estimated using Poisson regression. World standardized rates were derived from these and World Health Organization data.


RESULTS
The 650 chronically HBV-infected persons had higher rates of hepatocellular carcinoma (adjusted IRR = 8.70; 95% CI = 2.06 to 36.7), liver disease (adjusted IRR = 5.73, 95% CI = 3.52 to 9.34), and all-cause mortality (adjusted IRR = 1.47; 95% CI = 1.21 to 1.79) than the 5160 HBV-negative persons. However, the world standardized incidence rates of hepatocellular carcinoma (38.5 cancers per 100 000 person-years) and cirrhosis (24 cases per 100 000 person-years) among chronically HBV-infected persons were low compared with results from population-based studies from countries with low, intermediate, and high rates of endemic HBV infection.


CONCLUSIONS
The relatively low incidence of hepatocellular carcinoma and other HBV-related morbidity among chronic HBV-infected persons in Greenland suggest a more benign course of HBV among the Greenlandic Inuit than in populations in other parts of the world.
Department of Epidemiology Research, Statens Serum Institut, Ørestads Boulevard 5, Copenhagen, Denmark. mlb@ssi.dk
Malene L
ML
Børresen
Anders
A
Koch
Robert J
RJ
Biggar
Mikael
M
Andersson
Jan
J
Wohlfahrt
Karin
K
Ladefoged
Mads
M
Melbye
D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000453:epidemiology* / Q000401:mortality / Q000821:virology*; D015331:Cohort Studies; D016001:Confidence Intervals; D003718:Denmark / Q000453:epidemiology / Q000208:ethnology; D005260:Female; D006116:Greenland / Q000453:epidemiology; D006515:Hepatitis B virus / Q000276:immunology / Q000302:isolation & purification*; D019694:Hepatitis B, Chronic / Q000150:complications*; D006801:Humans; D015994:Incidence; D004930:Inuit / Q000706:statistics & numerical data*; D008107:Liver Diseases / Q000453:epidemiology* / Q000401:mortality / Q000821:virology*; D008113:Liver Neoplasms / Q000453:epidemiology / Q000821:virology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D016012:Poisson Distribution; D015995:Prevalence; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors