Low serum 25-hydroxyvitamin D level: An independent risk factor for tuberculosis?

Background & aims: Vitamin D deficiency has been associated with an increased risk of tuberculosis (TB). Low serum vitamin D levels may also be associated with poor nutritional status in TB patients. Therefore, this study aimed at evaluating the association between low serum vitamin D level and TB, regardless of other nutritional factors. Methods: Baseline serum 25-hydroxyvitamin D (25(OH)D3) levels in TB patients were measured before treatment and 1 year after treatment onset using liquid chromatography tandem mass spectrometry, and were compared with 25(OH)D3 levels in controls. Nutritional parameters were also measured in all subjects. Results: In total, 165 active pulmonary TB patients and 197 controls were included in the study. Significantly higher prevalence of 25(OH)D3 insufficiency (<20 ng/mL) and deficiency (<10 ng/mL) in TB patients was showed compared to controls. Serum 25(OH)D3 levels and nutritional parameters were significantly lower in untreated TB patients than in controls. One year after TB treatment onset, nutritional parameters significantly increased; however, serum 25(OH)D3 levels in TB patients showed no significant improvement compared to baseline. Conclusions: These results suggest that a low serum 25(OH)D3 level might be a risk factor for TB, independent of nutritional status. (C) 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.