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

Abstract

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.