The effects of the Korean reference value on the prevalence of osteoporosis and the prediction of fracture risk

Background: Since the reference value is the core factor of the T-score calculation, it has a significant impact on the prevalence of osteoporosis. The purpose of this study was to determine the effects of using the Korean reference value on the prevalence of osteoporosis and on the prediction of fracture risk. Methods: We used femoral neck bone mineral density (BMD) data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2011. The Korean reference was identified by the mean and standard deviation of men and women aged 20-29 years. We compared the prevalence and the fracture risk assessment tool (FRAX (TM)) probability obtained from the Korean reference and the NHANES III reference. Results: In men, the prevalence of osteoporosis increased when using the Korean men's reference, and the difference increased up to 9% for those in their 80s. In women, the prevalence increased when using the NHANES III reference, and the difference increased up to 17% for those in their 80s. The reference value also affected the fracture risk probability, and the difference from changing the reference value increased in women and in subjects with more clinical fracture risk factors. In major osteoporotic fractures, the difference of the risk probability was up to 6% in women aged 70-79 years with two clinical risk factors. For femoral neck fractures, the difference was up to 7% in women aged 50-59 years with two clinical risk factors. Conclusions: We confirmed that the reference value had significant effects on the prevalence of osteoporosis and on the fracture risk probability. The KNHANES 2008-2011 BMD data reflected the characteristics of the Korean BMD status well with regard to data size and study design; therefore, these data can be used as reference values.