Vitamin D levels in Indian children with intrathoracic tuberculosis

Background & objectives: Deficiency of vitamin D, an immunomodulator agent, is associated with increased susceptibility to tuberculosis in adults, but only limited studies are available in the paediatric age group, especially regarding association of vitamin D with type and outcome of tuberculosis. We conducted this study to determine the baseline 25-hydroxy vitamin D levels in children suffering from intrathoracic tuberculosis and its association with type and outcome of tuberculosis. Methods: Children with intrathoracic tuberculosis, diagnosed on the basis of clinico-radiological criteria, were enrolled as part of a randomized controlled trial on micronutrient supplementation in paediatric tuberculosis patients. Levels of 25-hydroxy vitamin D were measured in serum samples collected prior to starting antitubercular therapy by chemiluminescent immunoassay technology. Results: Two hundred sixty six children (mean age of 106.9 +/- 43.7 months; 57.1% girls) were enrolled. Chest X-ray was suggestive of primary pulmonary complex, progressive disease and pleural effusion in 81 (30.5%), 149 (56%) and 36 (13.5%) subjects, respectively. Median serum 25-hydroxy vitamin D level was 8 ng/ml (IQR 5, 12). One hundred and eighty six (69.9%) children were vitamin D deficient (serum 25-hydroxy vitamin D <12 ng/ml), 55 (20.7%) were insufficient (12 to <20 ng/ml) and 25 (9.4%) were vitamin D sufficient (>= 20 ng/ml). levels of 25-hydroxy vitamin D were similar in all three types of intrathoracic tuberculosis, and in microbiologically confirmed and probable cases. Levels of 25-hydroxy vitamin D did not significantly affect outcome of the disease. Children who were deficient or insufficient were less likely to convert (become smear/culture negative) at two months as compared to those who were 25-hydroxy vitamin D sufficient (p<0.05). Interpretation & conclusions: Majority of Indian children with newly diagnosed intrathoracic tuberculosis were deficient in vitamin D. Type of disease or outcome was not affected by 25-hydroxy vitamin D levels in these children. However, children who did not demonstrate sputum conversion after intensive phase of antitubercular therapy had lower baseline 25-hydroxy vitamin D levels as compared to those who did.