In the above context the mechanisms linking vitamin D deficiency and its effect on tuberculosis are currently under investigation. In order to understand the link two types of studies have been conducted (a) clinical studies associating vitamin D deficiency and tuberculosis and (b) in-vitro assessment of molecular immune changes related to vitamin D exposure. With the currently available knowledge, the linkage between the two disorders is being explained by the broad role of vitamin D deficiency in modulation of cell-mediated immunity.