Inflammation is the main determinant of low bone mineral density in pediatric inflammatory bowel disease.

AIMS

To assess bone mineral density (BMD) in children with Crohn's disease (CD) and ulcerative colitis (UC) and to investigate the role of inflammation and steroids on BMD.

METHODS

Lumbar spine areal BMD was measured by DXA, and volumetric BMD was then estimated (BMAD); inflammatory cytokines (TNF-alpha, IL-6, IL-10, and IL-12) were dosed in peripheral blood; and cumulative and daily doses of steroids were calculated. Therapy with infliximab (IFX) was considered for CD patients.

RESULTS

Fifty-six patients with IBD (35 CD, 21 UC) were studied. An inverse correlation was found between BMAD and IL-6 in patients with UC (r = -0.65); no correlation was found between BMAD and serum levels of TNF-alpha, IL-10, and IL-12 in all patients. Disease activity indexes use inversely correlated with BMAD (r = -0.62 in patients with CD and r = -0.64 in patients with UC). Cumulative dose of corticosteroids and duration of therapy did not correlate with BMAD. The 10 patients with CD who were treated with IFX had higher BMAD (-1 +/- 0.8) than those never treated with IFX (-1.8 +/- 0.8). Mean Pediatric Crohn's Disease Activity Index and body mass index in patients with CD (R(2) = 0.48) and IL-6 level in patients with UC (R(2) = 0.43) were found to be independent and significant predictors of BMAD.

CONCLUSIONS

In children with IBD, inflammation is an important determinant of bone loss, as shown by the correlation of BMAD with serum IL-6 and with disease activity indexes as well as by the beneficial effect of IFX on bone density. Corticosteroids seem to be a less important variable in pediatric IBD-related BMD reduction than previously believed.