BONE ASSESSMENT IN PATIENTS WITH ILEAL POUCH-ANAL ANASTOMOSIS FOR INFLAMMATORY BOWEL-DISEASE

Background Patients with ulcerative colitis are at risk of low bone mi neral density (BMD). Proctocolectomy with ileal pouch-anal anastomosis (IPAA) for ulcerative colitis diminishes the risk of bone disease. Th e aims of this study were to assess the mechanism of low BMD and to me asure bone density changes after IPAA. Methods Twenty patients with IP AA for ulcerative colitis, of mean(s.d.) age 38(9) (range 21-58) years , had measurements of lumbar spine and femoral neck BMD by dual energy X-ray absorptiometry, a mean(s.d.) 28(23) (range 3-84) months after p roctocolectomy. Serum levels of calcium, phosphate, parathyroid hormon e, osteocalcin and 25-hydroxy vitamin D were determined. Fifteen patie nts were followed for 28(12) (range 8-50) months. Results At baseline, six patients had spine BMD more than two standard deviations below th e normal value, and three had vertebral crush fractures. Mean vitamin D values were normal and no patient had osteomalacia. BMD increased wi th time elapsed since IPAA (spine: r=0.71, P=0.005). During follow-up, mean(s.d.) changes in bone density were + 2.3(3.8) and + 2.1(5.6) per cent per year at the spine and femoral neck respectively. Conclusion These results suggest that in patients with IPAA for ulcerative coliti s, low BMD is not associated with vitamin D malabsorption and may be r eversible after surgery.