Pediatric Rheumatology Online Journal → August 2003 → Bone: Miscellaneous Topics → Abstract #148

BONE MINERAL DENSITY ASSESSED BY DEXA DOES NOT IMPROVE SPONTANEOUSLY DURING PUBERTY IN BOYS AND GIRLS WITH UNTREATED MILD OSTEOGENESIS IMPERFECTA

D. Wenkert,¹ M. N. Podgornik,¹ W. H. McAlister,² M. P. Whyte.¹

¹Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children, St. Louis, MO; ²Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO

Osteogenesis imperfecta types I and IV are the relatively mild forms of this autosomal dominant, type I collagenopathy. Both types feature osteopenia with recurrent fractures. Blue sclera help to diagnose type I disease. It is widely held that the severity of OI (fracture incidence) decreases at the time of puberty. To explore this assumption, charts from 12 Caucasian girls and 12 boys (9 Caucasian, 2 black, 1 Oriental) with relatively mild OI who had never received pharmacologic therapy were reviewed. Nearly all patients had undergone 3 or more bone density studies by DEXA (Hologic) between the ages of 10 and 20 years. Changes in BMD Z-scores (matched for age) were assessed using Hologic software for L₁-L₄ and using a Pediatric Bone Mineral Density Applet (http://www-stat-class.stanford.edu/pediatric-bones) for total hip and femoral neck. Changes were assessed for sequential determinations. Although fracture frequencies decreased, there was no significant trend for improvement in BMD Z-scores at any of these sites "across" puberty. Decreased fracture frequency in OI at the time of puberty could reflect changes in physical activity, enhanced bone quality, and/or better skeletal geometry, but we find no DEXA evidence for spontaneous improvement in BMD Z-scores.