In children with inflammatory bowel disease (IBD) it is not known whether reductions in bone mineral density (BMD) are a consequence of bone turnover alterations and if BMD improves with treatment.
In a cohort of children with IBD, we prospectively measured indicators of bone remodeling, body mass index (BMI), disease activity, intact parathyroid hormone, serum IL-6, and insulin-like growth factor-I at diagnosis and then every 6 months for 2 years. BMD was determined annually using dual x-ray absorptiometry (DXA). BMD Z-scores were calculated using height/age. Baseline measurements and calcium intake were compared with a group of age- and sex-matched healthy children.
We observed that at diagnosis total body BMD Z-score (mean ± SD) was −0.78 ± 1.02 for Crohn's disease (CD, n = 58), −0.46 ± 1.14 for ulcerative colitis (UC, n = 18), and −0.17 ± 0.95 for control (CL, n = 49) (P < 0.01, CD versus CL). In CD, a BMD Z-score <−1.0 was associated with lower BMI and higher serum IL-6. Patients with CD and UC had low bone turnover. Activation of bone formation paralleled clinical improvement, but BMC gain was less than expected over the 2-year study period, especially in CD. Prednisone use did not correlate with low BMD.
Decreased bone turnover occurs in children newly diagnosed with IBD. Although indicators of osteoblast activity increase with clinical improvement, bone mineral accrual does not accelerate. Children with low BMI may be considered for BMD screening, since they are at risk for low bone mass.
1 Connecticut Children's Medical Center, Hartford, Connecticut, and the University of Connecticut School of Medicine, Farmington, Connecticut
2 Division of Rheumatology, Department of Medicine, Sunnybrook and Women's College Health Sciences Centre, and Department of Health Policy, Management and Evaluation, University of Toronto, Canada
3 The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
*Connecticut Children's Medical Center, Division of Gastroenterology & Nutrition, 282 Washington St., Hartford, CT 06106
Published online in Wiley Online Library (wileyonlinelibrary.com).
Grant sponsor: Senior Research Award of the Crohn's & Colitis Foundation of America; Grant sponsor: Crohn's & Colitis Foundation of Canada; Grant sponsor: University of Connecticut Health Center General Clinical Research Center NIH; Grant Number: M01RR06192.