Altered Bone Mass in Children at Diagnosis of Crohn Disease: A Pilot Study

Abstract

Recent studies have indicated that bone mineral density is reduced in children with inflammatory bowel disease. The exact cause of this reduction is unclear, but it is often attributed to corticosteroid use. This study examined the prevalence of reduced bone mass in otherwise healthy children newly diagnosed with Crohn disease without previous corticosteroid exposure. Eighteen steroid-naive children newly diagnosed with Crohn disease underwent dual energy x-ray absorptiometry. Disease activity, growth and pubertal development, nutritional assessment and bone mass measurements were recorded. z scores were adjusted for bone age. Five of the 18 patients (28%) had a total bone mineral density z score less than -1 (one had a z score less than -2). Ten (56%) subjects had lumbar spine bone mineral density z scores less than -1 (two had z score less than -2). The subjects had significantly reduced mean lumbar spine bone mineral density z scores (P = 0.002). Delayed pubertal development correlated with whole body bone mineral density z scores (r = 0.64; P = 0.004). Most subjects were not meeting United States recommended dietary allowances for daily intake of calcium, vitamin D and total calories. The majority of subjects were not participating in weight-bearing physical activity. Decreased bone mass is common in steroid naive children newly diagnosed with Crohn disease. Crohn disease appears to contribute to impaired bone mass independent of corticosteroid therapy.