Lumbar spine bone mineral density at diagnosis and during follow-up in children with IBD.

Lumbar spine body mineral density (BMD) was measured in 123 children (65 male, 58 female) suffering from inflammatory bowel disease (IBD) (82 Crohn's disease, 41 ulcerative colitis) and in 46 children (25 male, 21 female) without any history of bone disease. Results in normal children showed that densitometer-derived reference values overestimated spine BMD, particularly for young children, such that the reported mean Z-scores for normal 10-yr-old children were -0.83 for males and -0.72 for females. For children with Crohn's disease, the lumbar spine BMD was further reduced (Z-score = -1.44 for males, Z-score = -1.37 for females). For children with ulcerative colitis, the lumbar spine BMD was similar to that of normal children (Z-score = -0.93 for males, Z-score = -0.56 for females). There was no statistically significant reduction in average spine BMD Z-scores during follow-up periods ranging from 1.7 to 8.7 yr. When growth patterns were examined in individual children, six patients (three Crohn's disease, three ulcerative colitis) were identified as losing spine BMD with respect to their baseline value and their expected pattern of BMD increase associated with normal growth. The children suffering from IBD who, most likely, will not maintain expected growth-related increases in spine BMD are those who are male, relatively young at diagnosis, and unlikely to be taking immunosuppressants.