Vitamin D level in ankylosing spondylitis male patients: A potential association with the functional status and platelet count

IntroductionsAnkylosing spondylitis (AS), spondyloarthritis (SpA) prototype characteristically involves the axial skeleton and enthesis. The pathogenesis of AS is multifactorial, however it has been reported that one important factor that might contribute is vitamin D deficiency. Vitamin D and platelets share specific roles in immune response, bone health and mineral metabolism.Aim of the workTo evaluate the serum vitamin D levels in AS patients and to study the relationship to clinical manifestations, disease activity, mobility and functionality.Patients and methodsThe study included 33 male AS patients and 33 matched control. Bath AS metrology index (BASMI), Bath AS disease activity index (BASDAI) and Bath AS functional index (BASFI) were evaluated. Serum 25-hydroxy vitamin D3 level was measured.ResultsThe 33 patients had a mean age of 37.2 ± 10.7 years, disease duration of 12.7 ± 6.8 years. 3 were ex-smokers, 15 currently and 15 never smoke. The mean BASDAI was 4.2 ± 2.1, 19 (57.6%) had BASDAI score ≥ 4 (active). The BASMI was 5.7 ± 1.4 and BASFI was 5.3 ± 2.6. Patient’s vitamin D level (7.2 ± 5.2 ng/ml) was lower significantly than in the control (21.3 ± 10.1 ng/ml) (p < 0.001). There were no differences in the level of vitamin D according to the smoking status (p = 0.9). A significant inverse relation was detected between vitamin D level and BASFI (r = -0.35, p = 0.045) and a significant correlation with the platelet level (r = 0.38, p = 0.027).ConclusionLow vitamin D level may contribute significantly to the pathogenesis of AS. It is significantly related to the impaired function in the disease and to low platelet count.