Mutifactorial analysis of risk factors for reduced bone mineral density in patients with Crohn's disease.
OBJECTIVE
To determine the prevalence of osteoporosis in a cohort of patients with Crohn's disease (CD) and to identify the relative significance of risk factors for osteoporosis.


METHODS
Two hundred and fifty-eight unselected patients (92 M, 166 F) with CD were studied. Bone mineral density (BMD) was measured at the lumbar spine and hip by dual X-ray absorptiometry. Bone formation was assessed by measuring bone specific alkaline phosphatase (BSAP) and bone resorption by measuring urinary excretion of deoxypyridinoline (DPD) and N-telopeptide (NTX).


RESULTS
Between 11.6%-13.6% patients were osteoporotic (T score < -2.5) at the lumbar spine and/or hip. NTX levels were significantly higher in the patients with osteoporosis (P < 0.05) but BSAP and DPD levels were not significantly different. Independent risk factors for osteoporosis at either the lumbar spine or hip were a low body mass index (P < 0.001), increasing corticosteroid use (P < 0.005), and male sex (P < 0.01). These factors combined accounted for 23% and 37% of the reduction in BMD at the lumbar spine and hip respectively.


CONCLUSIONS
Our results confirm that osteoporosis is common in patients with CD and suggest that increased bone resorption is the mechanism responsible for the bone loss. However, less than half of the reduction in BMD can be attributed to risk factors such as corticosteroid use and low BMI and therefore remains unexplained.
Bartram
Sarah A
SA
Department of Medicine, Freeman Hospital, Newcastle-upon-Tyne, NE7 7DN, United Kingdom.
Peaston
Robert T
RT
Rawlings
David J
DJ
Walshaw
David
D
Francis
Roger M
RM
Thompson
Nick P
NP
D000305:Adrenal Cortex Hormones / Q000009:adverse effects / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000469:Alkaline Phosphatase / Q000378:metabolism; D000596:Amino Acids / Q000652:urine; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D001862:Bone Resorption / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D015331:Cohort Studies; D003424:Crohn Disease / Q000150:complications* / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D050723:Fractures, Bone / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010024:Osteoporosis / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology*; D012307:Risk Factors
D000305:Adrenal Cortex Hormones; D000596:Amino Acids; C036020:deoxypyridinoline; D000469:Alkaline Phosphatase