Vitamin D levels and bone metabolism in Chinese adult patients with inflammatory bowel disease

Objective We aimed to investigate the serum 25-hydroxyvitamin D3 (25[OH]D3) levels and bone metabolism in adult Chinese patients with inflammatory bowel disease (IBD) and to evaluate the correlation between vitamin D levels and the disease activity as well as the potential risk factors. Methods Age- and gender-matched cohort of IBD patients (124 with ulcerative colitis [UC] and 107 with Crohn's disease [CD]) and 122 healthy controls were enrolled in this study. Serum levels of 25(OH)D3 and bone mineral density (BMD) were measured, and the correlation between the two parameters and the severity of the disease as well as the clinical risk factors were analyzed. Results Serum 25(OH)D3 levels were lower in UC (10.32 ± 4.46 ng/mL, P < 0.001) and CD patients (11.57 ± 5.02 ng/mL, P = 0.029) than that in healthy controls (12.87 ± 4.40 ng/mL). 25(OH)D3 levels were negatively correlated with the disease severity of both UC (r = −0.371, P < 0.001) and CD (r = −0.285, P = 0.030). The incidences of osteopenia and osteoporosis were high in the IBD patients (37.9% and 3.2% in UC and 30.8% and 4.7% in CD, respectively). Cumulative quantity of glucocorticoids use was significantly associated with osteopenia and osteoporosis in both UC (odds ratio [OR] 1.219, 95% confidence interval [CI] 1.054−1.410, P = 0.008) and CD patients (OR 1.288, 95% CI 1.033−1.606, P = 0.025). Conclusions Vitamin D deficiency is likely to occur in Chinese patients with IBD and is closely associated with the severity of the disease. Glucocorticoids accumulation is a risk factor for osteopenia and osteoporosis.