Objective: 1. To evaluate serum vitamin 25(OH)D3 concentrations in the patients with ankylosing spondylitis. 2. To assess the relationship between 25(OH)D3 levels and disease levels. Subject and method: A cross-sectional study included 40 patients meeting the New York A 1984 criteria for ankylosing spondylitis, at the age of or = 17 at Bach Mai Hospital from January 2013 to January 2014. Result and conclusion: The mean serum vitamin 25(OH)D3 level was 20.6 +/- 7.6ng/ml
90 percent of the patients had serum vitamin 25(OH)D3 concentrations below 30ng/ml. There was the relationship between vitamin 25(OH)D3 levels and pain levels, BASDAI, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP).