German researchers have linked low levels of vitamin D with high levels of hepatitis B virus (HBV), suggesting the "sunshine vitamin" may help keep the virus from spreading throughout the liver.
 

The findings — published online in Hepatology, a journal of the American Association for the Study of Liver Diseases — suggest seasonal fluctuations in vitamin D and HBV levels, tied to sun exposure, may also play a role in patients infected with the virus.
 

While highly effective vaccines are available, HBV is a major infectious disease, with the World Health Organization saying it is 50 to 100 times more infectious than human immunodeficiency virus (HIV), the AIDS virus. About two billion people have been infected with HBV, which kills 600,000 each year. The Centers for Disease Control and Prevention estimate up to 1.4 million Americans are living with chronic HBV.
 

"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 [HCV]," said lead investigator Christian Lange, M.D. from Johann Wolfgang Goethe University Hospital in Frankfurt. "However, the relationship between vitamin D metabolism and chronic HBV infection remains unknown and is the focus of our present study."
 

For the study, Dr. Lange and colleagues measured vitamin D levels in 203 patients with chronic HBV who had not previously received treatment for their infection. Results show that 34 percent of participants had severe vitamin D deficiency and 19 percent had normal levels. The also showed the concentration of HBV in the blood was a strong indicator of low vitamin D levels.
 

"Our data confirm an association between low levels of vitamin D and high concentrations of HBV in the blood," said Dr. Lange. "These findings differ from previous research of patients with chronic hepatitis C, which found no connection between vitamin D levels and concentration of HCV in the blood."
 

The researchers said future studies should seek to determine if vitamin D can be an effective therapy for controlling HBV.