Age-related bone mineral density,bone loss rate,prevalence of osteoporosis and reference database of women at multiple centers in China

Objective Our study surveyed age-related bone mineral density(BMD),bone loss rate,and prevalence of osteoporosis in women at multiple research centers in China.Survey results were used to establish a BMD reference database for the diagnosis of osteoporosis in Chinese women nationwide.Methods Utilized dual-energy X-ray absorptiometry(DXA) bone densitometers to measure BMD at posteroanterior(PA) lumbar spine(L_1-L_4)(n= 8 142) and proximal femur(n= 7 290) in female subjects age 20～89 years from Beijing,Shanghai,Guangzhou,Chengdu,Nanjing,and Jiaxing.A cubic regression-fitting model was used to describe the change of BMD with age at various skeletal sites.Results Peak BMD occurred between the ages of 30 to 34 years for femur neck and total femur,and between 40～44 years for spine and trochanter measurement sites.Young adult(YA) BMD values(mean and standard deviation(SD),calculated as the average BMD in the age range of 20～39,were 1.116±0.12 g/cm2,0.927±0.12 g/cm2,0.756±0.11 g/cm2 and 0.963±0.13 g/cm2 at PA spine,femoral neck,trochanter,and total femur,respectively.The BMD of 85 year old women reflected a loss of 32% at the spine and 30% to 35% at femur measurement sites.The prevalence of osteoporosis,defined as a BMD of ≤-2.5 standard deviations from YA values established in this study,in female subjects age 50 years or older,was 28% for the spine,15% for any femur site,and 31% for any spine or femur site.Conclusion This study provides important information for formulating osteoporosis prevention and treatment strategies in Chinese women,and it establishes a reliable BMD reference database for the diagnosis of osteoporosis of Chinese women nationwide.