BACKGROUND AND OBJECTIVE Vitamin D deficiency has been reported to be associated with the development of active tuberculosis (TB), but many discrepancies exist among studies. The aims of this study were to compare the frequency of vitamin D deficiency in a Korean population of TB patients and control subjects, and to monitor the changes in vitamin D levels during TB treatment.

METHODS Patients with newly diagnosed TB were prospectively enrolled. In addition, healthy volunteers or patients with diseases other than TB were enrolled as controls. Baseline serum 25-hydroxyvitamin D (25-OHD) levels were measured in both groups and compared. In the TB patients, measurements of serum 25-OHD were repeated 1 month after the initiation of treatment and again after completion of treatment.

RESULTS In total, 116 patients with TB and 86 control subjects were recruited. The median 25-OHD concentration was not different in TB patients at diagnosis (13.9 ng/mL; interquartile range (IQR) 8.80-21.8) compared with control subjects (13.2 ng/mL; IQR 9.6-19.3) (P = 0.97). The frequency of vitamin D deficiency (≤ 10 ng/mL) was also not different in TB patients (36.2%) compared with controls (27.3%) (P = 0.21). In TB patients, the median 25-OHD concentration decreased significantly during treatment, to 12.5 ng/mL at 1 month and 11.0 ng/mL on completion of treatment (P = 0.01).

CONCLUSIONS Vitamin D levels do not appear to be associated with the development of TB in the Korean population. The median 25-OHD concentration decreased after treatment for TB.