By Michael Smith, North American Correspondent, MedPage Today
Published: June 08, 2013
Reviewed by Zalman S. Agus, MD; Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania
- Low 25(OH)D3 serum levels are associated with high levels of HBV replication in patients with chronic hepatitis B.
- 25(OH)D3 and HBV DNA serum levels showed inverse seasonal fluctuations.
Vitamin D deficiency might be a key player in hepatitis B (HBV) replication, researchers reported.
Low levels of 25-hydroxyvitamin D predicted high levels of the virus and vice versa, said Christian Lange, MD, and colleagues at the Johann Wolfgang Goethe University Hospital in Frankfurt, Germany, in a retrospective case-control study.
Similarly the seasonal variation in 25-hydroxyvitamin D was reflected in an inverse variation of the virus, suggesting a "functional relationship" between the two, Lange and colleagues reported online in Hepatology.
Chronic HBV is difficult to cure although -- like HIV -- viral replication can be controlled by antiretroviral drugs. Nonetheless, better therapies are needed, Lange and colleagues noted.
"Vitamin D helps maintain a healthy immune system and there is evidence of its role in inflammatory and metabolic liver disease, including infection with hepatitis C virus," Lange said in a statement.
"However, the relationship between vitamin D metabolism and chronic HBV infection remains unknown and is the focus of our present study," he said.
Lange and colleagues looked back at samples taken from consecutive treatment-naïve HBV patients at their Frankfurt clinic from 2009 through 2012, excluding those with HIV, hepatitis C or D, excessive alcohol use, and liver or other cancers.
Aside from HIV viral load, the researchers also measured levels of 25-hydroxyvitamin D, where less than 10 nanograms per milliliter was defined as severe deficiency of the vitamin, 10 or more but less than 20 was deemed insufficient, and 20 or more was adequate.
Among the 203 patients, they found 34% had severe vitamin D deficiency, 47% had insufficient vitamin, and 19% had normal levels. The average concentration of 25-hydroxyvitamin D was 14.4 nanograms per milliliter.
Moreover, HBV viral load and 25-hydroxyvitamin D levels had an inverse relationship that was significant at P=0.0003, they reported.
In multivariate logistic regression analyses, they found:
- 25-hydroxyvitamin D was significantly associated with HBV viral load (P=0.0013)
- Conversely, HBV viral load was also associated significantly with 25-hydroxyvitamin D levels (P=0.000048)
In patients with low HBV DNA -- less than 2,000 IU per milliliter, a cutoff regarded as relevant for clinical decision-making -- levels of 25-hydroxyvitamin D averaged 17 nanograms per milliliter.
In contrast, among patients with higher viral loads of 2,000 IU per milliliter or more, 25-hydroxyvitamin D levels averaged 11 nanograms per milliliter, Lange and colleagues reported.
They also found that HBV DNA levels were significantly lower (P=0.01) when samples were taken in spring or summer compared with autumn or winter -- a "reciprocal seasonal variation" of both variables.
Interestingly, the findings contrast with research into the same issue in hepatitis C, "which found no connection between vitamin D levels and concentration of HCV in the blood," Lange said.
The researchers cautioned that associations do not prove causality and "the suggestive functional link between vitamin D metabolism and HBV replication therefore remains elusive."
They also noted that the cohort was composed of treatment-naïve patients and can't be extended to all HBV patients.
The researcher had support from the Deutsche Forschungsgemeinschaft, the Johann Wolfgang Goethe University, and the Deutsche Leberstifung. The journal said the authors reported they had no conflicts.
Primary source: Hepatology
Farnik H, et al. "Low vitamin D serum concentration is associated with high levels of hepatitis B virus (HBV) replication in chronically infected patients." Hepatology 2013.