Aibana O, Huang CC, Aboud S, et al. - In a prospective cohort of 6,751 HIV-negative household contacts of TB patients recruited between September 1, 2009, and August 29, 2012, in Lima, Peru, researchers evaluated the influence of baseline vitamins D levels on TB disease risk. Serum 25–(OH)D levels in individuals at high risk for TB disease were measured and the development of TB over 1 year was followed up. Individuals with low levels of vitamin D were at greater risk of future progression to TB disease. The findings suggested that vitamin D prognosticates TB disease risk in a dose-dependent manner and that the risk of TB disease is greatest among HIV-positive individuals with severe vitamin D deficiency. Randomized control trials are required to assess the possible role of vitamin D supplementation on overcoming TB disease risk.