Revised reference curves of bone mineral density according to age and sex for Iranian children and adolescents

Abstract

Summary: Bone health evaluation in children requires an appropriate reference database. We have shown higher curves for spine aBMD in Iranian subjects than Americans, but lower curves for femoral neck and total body. These results can be used as reference values to assist Iranian clinicians in interpreting and monitoring bone densitometry results. Purpose: Bone health evaluation requires an appropriate reference database that can identify the bone deficit according to age, sex, puberty, and race. The aim of this study was to determine bone mineral density Z-scores in Iranian children and adolescents and their comparability with other reference data. Methods: A sample of 476 healthy children and adolescents, aged 9–18 years, from Kawar (an urban community, 50 km east of Shiraz, Iran) was selected and bone mineral measurements of the lumbar spine, femoral neck, and total body (less head) were done. Sex-specific height-for-age, weight-for-age, and BMI-for-age Z-scores, as well as bone mineral density Z-scores, were calculated. Results: Extended reference curves for bone mineral content (BMC) and areal bone mineral density (aBMD) of the total body less head, lumbar spine, and femoral neck, for ages 9–18 years were constructed relative to sex and age. We found that median, − 2SD, and + 2SD curves for the lumbar spine aBMD were higher in Iranian subjects than in the American participants, but the curves of the femoral neck and total body were lower. Also, we showed that subjects with a lower height-for-age Z-score had a lower BMC and aBMD Z-score in the lumbar spine, femoral neck, and total body (p < 0.001). Conclusions: Relevant differences in bone mineral density and its curves exist between Iranian children and adolescents and other databases, revealing a significant potential for misdiagnosis. However, our results can be used to provide reference databases to assist clinicians in interpreting, assessing, and monitoring bone densitometry.