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

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. We used dual-energy X-ray absorptiometry bone densitometers to measure BMD at posteroanterior (PA) lumbar spine (L1-L4; n = 8142) and proximal femur (n = 7290) in female subjects of age 20-89 yr 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. Peak BMD occurred between 30 and 34 yr of age for femur neck and total femur, and between 40 and 44 yr 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, 0.927 +/- 0.12, 0.756 +/- 0.11, and 0.963 +/- 0.13 g/cm(2) at PA spine, femoral neck, trochanter, and total femur, respectively. The BMD of 85-yr-old women reflected a loss of 32% at the spine and 30-35% at femur measurement sites. The prevalence of osteoporosis, defined as a BMD of <= -2.5 SDs from YA values established in this study, in female subjects of age 50 yr or older, was 28% for the spine, 15% for any femur site, and 31% for any spine or femur site. 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.