R. Dresner-pollak et al., Increased urinary N-telopeptide cross-linked type 1 collagen predicts boneloss in patients with inflammatory bowel disease, AM J GASTRO, 95(3), 2000, pp. 699-704
OBJECTIVE: Reduced bone mineral density (BMD) is common in patients with in
flammatory bowel disease (IBD), but the factors associated with its longitu
dinal rate of change have not been established. We prospectively assessed t
he rate of change in BMD, and its association with biochemical markers of b
one turnover.
METHODS: Twenty-two patients with Crohn's disease and 14 ulcerative colitis
patients age 37.1 +/- 11.6 yr were followed for 2 yr. Lumbar spine (L2-L4)
and femoral neck BMD were measured by dual x-ray absorptiometry at baselin
e and 24 months. Bone-specific alkaline phosphatase, osteocalcin, urinary N
-telopeptide crosslinked type 1 collagen (NTx), parathyroid hormone, and 25
-hydroxyvitamin-D were determined at baseline.
RESULTS: At baseline, 59% of Crohn's patients and 43% of ulcerative colitis
patients were osteoporotic, with spine or femoral neck BMD T-score <-2.5.
Spine BMD, and spine and femoral neck T-scores were lower and disease durat
ion was longer in nine patients with ileal resection compared with nonopera
ted patients (0.84 +/- 0.15 g/cm(2) vs 0.96 +/- 0.11 g/cm(2), -3.0. +/- 1.5
vs -1.7 +/- 1.3, -3.2 +/- 1.5 vs -2.2 +/- 1.0, respectively; all p < 0.05)
. At 24 months, 13/36 (36%) and 14/36 (39%) patients experienced spinal and
femoral neck bone loss, respectively, with mean annual percent Bh ID chang
es of -2.0% and -1.5%, respectively. NTx, a bone resorption marker, inverse
ly correlated with spinal BMD rate of change (r = -0.4, p < 0.05). Using qu
artiles analysis, patients with the highest NTx (Q4) experienced the greate
st decrease in spine BMD compared with patients with the lowest NTx (Q1).
CONCLUSIONS: Spine and femoral neck bone loss continues over time in mon th
an one-third of IBD patients. Increased NTx level predicts spinal bone loss
in IBD patients. (Am J Gastroenterol 2000,95:699-704. (C) 2000 by Am. Coll
. of Gastroenterology).