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Low Vitamin D Linked to Greater Hepatitis B Virus Replication

Low blood levels of 25-hydroxyvitamin D were strongly associated with higher hepatitis B virus (HBV) viral load in a study of more than 200 untreated patients described in the May 22, 2013 advance online edition of Hepatology.

Vitamin D has multiple functions in the body, including effects on immune response and metabolism, but prior studies have yielded conflicting data about its role in specific diseases.

Harald Farnik from JW Goethe University in Frankfurt and colleagues measured serum levels of 25-hydroxyvitamin D -- or 25(OH)D3 -- in 203 treatment-naive chronic hepatitis B patients who had not yet received antiviral therapy.

Results

• At study entry, 34% of participants had severe vitamin D deficiency (25(OH)D3 <10 ng/mL), 47% had milder deficiency (<20 ng/mL), and 19% had adequate levels (>20ng/mL).
• In both univariate and multivariate analyses, low serum vitamin D was a strong and significant predictor ofhigher HBV DNA viral load, and vice versa.
• The mean serum vitamin D concentration was 17 ng/mL for patients with HBV DNA <2000 IU/mL, compared with 11 ng/mL for those with >2000 IU/mL, a significant difference.
• Hepatitis B "e" antigen (HBeAg) positive participants had significantly lower serum vitamin D levels than HBeAg negative patients.
• Serum vitamin D and HBV viral load showed inverse seasonal fluctuations, with vitamin D rising and HBV DNA falling during periods of greater sun exposure.

"Low 25(OH)D3 serum levels are associated with high levels of HBV replication in patients with chronic hepatitis B," the study authors concluded.

"Inverse seasonal fluctuations of 25(OH)D3 and HBV DNA serum levels are suggestive for a functional relationship between both variables," they added, but stressed that correlation does not necessarily imply causation.

"This represents a major difference to chronic hepatitis C," for which numerous previous studies have shown a lack of correlation between HCV viral load and vitamin D levels, they noted.

6/13/13

Reference

H Farnik, J Bojunga, A Berger, et al. Low vitamin D serum concentration is associated with high levels of hepatitis B virus (HBV) replication in chronically infected patients. Hepatology. May 22, 2013 (Epub ahead of print).