WASHINGTON (Reuters) - African immigrants with low levels of vitamin D are much more likely to be infected with tuberculosis, a finding that suggests the vitamin may help prevent and treat TB, Australian researchers said on Monday.
Their study of all 375 African immigrants treated at one Melbourne hospital showed that those who had low vitamin D levels were far more likely to have TB infections than those with adequate levels.
They found moderate to severe vitamin D deficiency in 78 percent of patients with past or present tuberculosis.
"Low vitamin D levels are associated with an increased likelihood of primary infection with Mycobacterium tuberculosis and also, once infected, are associated with increased likelihood of having active TB," Dr. Katherine Gibney of the Royal Melbourne Hospital said in a statement.
Writing in the journal Clinical Infectious Diseases, Gibney and colleagues said they tested everyone from sub-Saharan Africa treated at the hospital between 2003 and 2006.
Previous studies have shown that people with vitamin D deficiencies are more likely to have active TB. The researchers said theirs is the first to show this is true of latent TB as well.
TB affects up to a third of the world's population. Most cases are latent, meaning patients are infected but have no symptoms and are very unlikely to infect anyone else.
The disease takes months to cure with a cocktail of antibiotics and kills 1.6 million people a year, according to the World Health Organization.
Vitamin D is made when sunlight hits the skin, and food is often supplemented with the vitamin.
Gibney's team said doctors might consider vitamin D supplements as a treatment for TB, or a way to prevent it.
Reporting by Maggie Fox, editing by Will Dunham and Todd Eastham