Benign course of long-standing hepatitis B virus infection among Greenland Inuit?

OBJECTIVE

Chronic hepatitis B virus (HBV) infection can present in different ways, from inactive carrier to liver failure or cancer. The role of the virus subtype is controversial. The purpose of this study was to characterize HBV infection in detail and its impact on general health, body-build and liver biochemistry.

MATERIAL AND METHODS

The study comprised a population-based cohort of Inuit exposed to HBV 3-7 decades ago in the capital in West Greenland, a coastal town and four settlements in rural East Greenland. Participants included 95% of the invited Inuit: 229 men, 205 women, aged 50-69 years.

RESULTS

Only 25% of the participants had never had HBV infection. HBsAg was positive in 86 participants (20.0%), more being found positive in rural East Greenland than in the city in West Greenland (28.9% versus 2.7%; p < 0.001). HBV-DNA was positive in 61 of those with median HBV-DNA 40,000 copies/ml. HBV genotype could be determined in 52: 47 participants had genotype B, 4 genotype D, and 1 had both B and D. At sequencing, genotype B resembled subtype Bj, but with more than 5% diversity in the C-gene it could be a new subtype B. Pre-core mutation was found in 55 of 56 participants investigated. None of the participants had signs of liver disease, and HBV infection did not influence body-build or liver biochemistry.

CONCLUSIONS

More than 75% of participants had a marker of present or previous HBV infection but the infection seemed dormant. The majority harbored a special variant of genotype B that might be a new subtype giving a relatively benign disease. The role of detailed subtyping of HBV for prognostic evaluation should be investigated in more detail.