Bone mineral density, vitamin D, and disease activity in children newly diagnosed with inflammatory bowel disease.

Objective: The aim of this study was to examine bone mineral density and serum 25-hydroxy vitamin D in relation to disease activity in children newly diagnosed with IBD.

Methods: In a cross-sectional analytic study, 60 children newly diagnosed with IBD (39 with Crohn's disease [CD], mean age 12.2 ± 2.1 years; and 21 with ulcerative colitis [UC], mean age 12.4 ± 3.7 years) were recruited. Fifty-six age- and sex-matched children without IBD were invited as controls (mean age 11.3 ± 4.2 years). Serum 25-hydroxy vitamin D for patients and controls was measured at diagnosis. Patients' adjusted lumbar spine bone mineral density (BMD) z scores were measured. Activity indices for both CD and UC were calculated.

Results: The serum level of 25-hydroxy vitamin D was significantly lower in children with IBD compared to the control group (P = 0.04). BMD was significantly lower in patients with CD compared to those with UC (P = 0.039). There was no correlation between vitamin D levels, BMD z scores or disease activity indices for both CD and UC.

Conclusions: Serum vitamin D level is significantly lower in children with newly diagnosed IBD compared to those without. However, vitamin D levels are not affected by disease severity. It seems that BMD status may not be affected by vitamin D levels or disease severity in this cohort. Larger prospective controlled studies are needed to confirm these findings.