The association between vitamin D deficiency and extrapulmonary tuberculosis: Case-control study.

Tuberculosis remains a public health issue worldwide. Identifying its risk factors, such as vitamin D deficiency, is mandatory so as to target the preventive strategies. We aimed to study the association between vitamin D deficiency and extrapulmonary tuberculosis. We conducted a case-control study including all cases of extrapulmonary tuberculosis hospitalized in the infectious diseases department over a two-year period from April 2017 until April 2019. We included 45 cases of extrapulmonary tuberculosis and 45 controls matched by gender and age. Vitamin D deficiency was significantly more frequent among cases (80% vs 37.7%; p < 0.001), with an odds ratio (OR) of 6.5 (IC95% = 2.5-16). The mean levels of vitamin D were significantly lower among cases (11.9 ± 8.8 vs 22.3 ± 11 ng/mL; p < 0.001). In the multivariate analysis, we found that vitamin D deficiency was an independent predictor of extrapulmonary tuberculosis (OR = 6.13; p < 0.001). The cutoff value of vitamin D predictor of extrapulmonary tuberculosis was 18.5 ng/mL which was associated with a sensitivity of 80% and a specificity of 62%. Our study provides strong evidence that vitamin D deficiency was an independent predictor of extrapulmonary tuberculosis. More studies are needed in order to evaluate the potential preventive role of vitamin D and the benefit of possible supplementation.