Evolution of osteopenia in inflammatory bowel disease

OBJECTIVE: Our aim was the assessment of frequency and evolution of osteopenia in patients with inflammatory bowel disease and identification of related factors. METHODS: Bone mineral density (BMD) of the lumbar spine was measured in 54 patients with Crohn's disease (CD) and in 49 patients with ulcerative colitis (UC) and was repeated after a mean observation period of 21 (range, 8-50) months in 30 CD and 14 UC patients. Eighteen age-matched healthy subjects served as controls. Serum biochemistry (parathyroid hormone, osteocalcin, alkaline phosphatase, insulin-like growth factor 1, minerals, and markers of inflammation) was assessed at the time of the second BMD measurement. RESULTS: Reduced BMD values were found in 48% of CD, and in 38% of UC patients. Compared with control subjects, the mean BMD was significantly lower in CD (p < 0.003) and UC (p < 0.0001) patients. BMD was positively correlated with the body mass index (p < 0.05) and inversely correlated with the lifetime steroid dose (p < 0.03). After 21 months the BMD of CD patients was virtually unchanged, with an annual variation (%deltaBMD/yr) of -0.31 +/- 0.49, whether treated with steroids or not, whereas in UC patients the BMD decreased significantly (p < 0.02) with a %deltaBMD/yr of -2.47 +/- 0.82 (p < 0.02 vis CD). This decrease can be attributed to steroid treatment. No biochemical alterations were detected in patients with rapid bone loss, compared with those with stable BMD. CONCLUSIONS: Low bone density is frequent in both CD and UC, but apparently stable in CD. The evolution of BMD suggests that low bone density is associated with the pathogenesis of CD, whereas in UC it seems to be correlated with the side effects of corticosteroid treatment.