Reference values for bone mineral density according to age with body size adjustment in Korean children and...

Bone acquisition failure during growth or low bone mineral density (BMD) in childhood and adolescence might increase future osteoporosis risk. To identify these children and adolescents, appropriate reference values are necessary. The robust reference values must be community based as well as sex-, age-, and ethnicity specific. In addition, body size adjustment is necessary because individuals demonstrate different body sizes and different tempos of growth, which affect measured BMD. We aimed to provide reference data with body size adjustment of Korean children and adolescents. We used dual-energy X-ray absorptiometry data of 1,650 subjects (aged 10-20 years; 788 female) from the Korea National Health and Nutrition Examination Survey (2009-2010). The BMD of each region of interest (ROI), including the lumbar spine, total body less head, total body, and femoral neck, were obtained. We calculated the mean and percentiles for each ROI. Because height and weight variations were high and correlated independently with BMD within the same age group, we developed equations to calculate the "predicted BMD Z score." Although 12.8-17.9 % of subjects with short stature showed a low measured BMD Z score depending on the measured site, only 2.6 % of those of short stature had a low adjusted BMD Z score after applying the predicted BMD Z score. We also compared the BMD of children and adolescents of other ethnicities using the same device. This study provided robust reference values for the assessment and monitoring of bone health in Korean children and adolescents. Additionally, it extended the knowledge of bone acquisition in Asian children and adolescents.