Review article: bone disease in inflammatory bowel disease

Abstract

Inflammatory bowel disease (IBD) is associated with an increased incidence of osteoporosis. Osteoporosis with osteoporotic pain syndromes, fragility fractures and osteonecrosis accounts for significant morbidity and impacts negatively on the quality of life. It is generally agreed that there is a need to increase awareness for inflammatory bowel disease-associated osteoporosis. However, the best ways in which to identify at-risk patients, the epidemiology of fractures and an evidence-based rational prevention strategy remain to be established. The overall prevalence of IBD-associated osteoporosis is 15%, with higher rates seen in older and underweight subjects. The incidence of fractures is about 1 per 100 patient years, with fracture rates dramatically increasing with age. While old age is a significant risk factor, disease type (Crohn's disease or ulcerative colitis) is not related to osteoporosis risk. Corticosteroid use is a major variable influencing IBD-associated bone loss; however, it is difficult to separate the effects of corticosteroids from those of disease activity. The recommendations in inflammatory bowel disease are similar to those for postmenopausal osteoporosis, with emphasis on lifestyle modification, vitamin D (400-800 IE daily) and calcium (1000-1500 mg daily) supplementation and hormone replacement therapy (oestrogens/selective oestrogen receptor modulators in women, testosterone in hypogonadal men). Bisphosphonates have been approved for patients with osteoporosis (T-score < 2.5), osteoporotic fragility fractures and patients receiving continuous steroid medication. Data on the recently Food and Drug Administration-approved osteoanabolic substance parathyroid hormone and on osteoprotegerin are promising in terms of both steroid-induced and inflammation-mediated osteoporosis, the key elements of inflammatory bowel disease-associated bone disease.