The bone mineral density in childhood study: bone mineral content and density according to age, sex, and race.

CONTEXT: Low bone mass may increase risk of fracture. Several chronic medical conditions, medications, and lifestyle factors affect bone mineral accrual. Appropriate reference values are essential for identification of children with bone deficits. OBJECTIVE: Our objective was to establish reference curves for bone mineral content (BMC) and density (BMD) in children. DESIGN AND SETTING: The Bone Mineral Density in Childhood Study is an ongoing longitudinal study in which measurements are obtained annually at five clinical centers in the United States. PARTICIPANTS: Participants included 1554 healthy children (761 male, 793 female), ages 6-16 yr, of all ethnicities. MAIN OUTCOME MEASURES: Scans of the whole body, lumbar spine, hip, and forearm were obtained using dual-energy x-ray absorptiometry. Percentile curves based on three annual measurements were generated using the LMS statistical procedure. RESULTS: BMC of the whole body and lumbar spine and BMD of the whole body, lumbar spine, total hip, femoral neck, and forearm are given for specific percentiles by sex, age, and race (Black vs. non-Black). BMC and BMD were higher for Blacks at all skeletal sites (P < 0.0001). BMC and BMD increased with age, and a plateau was not evident by age 16 (girls) or age 17 (boys). The variation in BMC and BMD also increased with age. CONCLUSIONS: Age-, race-, and sex-specific reference curves can be used to help identify children with bone deficits and for monitoring changes in bone in response to chronic diseases or therapies.