Abstract: Abstract：Objective To explore the relation between vitamin D deficiency and susceptibility to spinal tuberculosis. Methods A total of 163 hospitalized patients with untreated spinal tuberculosis in Tianjin Haihe hospital were enrolled in this study from June 2013 to May 2016. A total of 170 individuals participated in health examination program at the same period were enrolled as the control group. The serum level of 25-hydroxyvitamin D [25(OH)D] was measured by enzyme linked immunosorbent assay. The 25(OH)D grading included serious deficiency group (<25 nmol/L), deficiency group (≥25 nmol/L and <50 nmol/L), insufficiency group (≥50 nmol/L and <75 nmol/L) and sufficiency group (≥75 nmol/L). Histopathological classification was confirmed by intraoperative findings. Results The serum level of 25(OH)D was significantly lower in patient group [23.99(20.55,29.54)nmol/L] than that of control group [42.94(35.68,51.04) nmol/L] (P< 0.01), and which was also significantly lower in four seasons than that of controls (P<0.05). The serum levels of 25(OH)D were significantly higher in summer group than those of winter group in both patient and control groups (P＜0.008 3). The proportion of patients with serious deficiency of 25(OH)D was significantly higher in spring and winter groups in patient group, which was significantly lower in summer group (P＜0.01). There was no significant difference in patients with serious deficiency of 25(OH)D between four seasons (P＜0.01). For control group, there was a higher proportion of cases with deficiency of 25(OH)D in four seasons, and there was no significant difference in the distribution of seasons (P＞0.05). In patient group, there were 107 cases of caseous necrosis type, 56 cases of hyperplasia type, and the proportion of caseous necrosis type was significantly higher in the severe deficiency group (79.17%, 76/96) than that of deficiency group (46.27%， 31/67, P＜0.01). Conclusion Excluding the effect of season, vitamin D deficiency is associated with susceptibility to spinal tuberculosis and histopathologic classification.

Key words: tuberculosis, spinal, vitamin D, disease susceptibility, histopathologic classification