| Objective To investigate the effect of active vitamin D on bone metabolism and disease activity in ankylosing spondylitis (AS) patients with low bone mineral density (BMD). Methods Sixty AS patients with low BMD and 20 healthy controls were selected. Bone specific alkaline phosphatase (BALP), tartrate resistant acid phosphatase-5b (TRACP-5b), and 25-(OH)D3 were compared between the two groups. The 60 AS patients were randomly divided into the control group (30 cases) and the treatment group (30 cases). The patients in the control group received meloxicam, sulfasalazine, and calcium carbonate. The patients in the treatment group received additional calcitriol. The serum levels of BALP, TRACP-5b, and 25-(0H)D3, BMD, erythrocyte sedimentation rate (ESR), and C reactive protein (CRP) were compared between the two groups. Results The serum levels of BALP and TRACP-5b in AS group were significant higher than those in healthy control group (P<0.05), and the serum level of 25-(0H)D3 was significant lower than that in healthy control group (P<0.05). The serum levels of BALP and 25-(OH)D3 increased significantly bone in the control group and the treatment group (P<0.05), while the serums levels of TRACP-5b decreased (P<0.05). The differences of BALP and 25-(OH)D3 before and after the treatment in treatment group were higher than those in the control group (P<0.05). BMD of the lumbar spine, great trochanter, and intertrochanteric increased more significantly in treatment group than those in the control group after 6 months (P<0.05), and BMD recovered to normal in 5 cases. The change of BMD in the control group was not obvious after the treatment (P<0.05). The levels of ESR, CRP, and BASDAI scores decreased in both groups (P<0.05). The decreased level of ESR score in the treatment group was more obvious than that in the control group (P<0.05). Conclusion Active vitamin D improves the bone metabolism and reduce the disease activities in AS patients with low bone mineral density. |