Studies on the standards for the bone mineral density measurement at forearm skeletal sites in the diagnosis of osteoporosis

Objective The aim of this study was to survey the age-related bone mineral density(BMD) and bone loss at peripheral skeleton in females to establish a reliable BMD reference database in peripheral densitometry for the establishment of diagnostic criteria of osteoporosis.Methods A total of 452 healthy female volunteers between ages 20～79 were recruited to participate in the measurement of bone mineral density at the nondominant forearm by peripheral dual X-ray absorptiometry(pDXA).The scan sites include a global distal site(radius + ulna),a global 1/3 proximal site (radius + ulna) and a 1/3 proximal radius site,and a cubic regression-fitting model was used to describe the change of BMD with age at various skeletal sites of forearm.Results It was showed that the BMD value at forearm skeletal sites was in line with the normal distribution and can be represented as mean±standard deviation.In females the peak density was found in the 40～44-yr group for the distal and proximal forearm,subsequently,a slight decrease in density occurred, but there was a rapid bone loss between ages 50～59 and over age 70,the accumulated bone loss between ages 55～59 reached 25%at distal radial and ulna measurement sites,with the same trend as that at central skeletal sites with DXA. The prevalence of osteopenia and osteoporosis in females aged 50～54 years was 57.6%,25.8%(T-score criteria of -2.0 or below) and 12.1%(T-score criteria of -2.5 or below),while at age 55～59,it reached 80.9%,50.0%and 30.9%,respectively.Between ages 60～70,the increase of prevalence rate of osteopenia and osteoporosis was slowing down,but a significant increase was observed in females greater than 70 years of age.Conclusion BMD Measurements at forearm skeletal sites might be sensitive to reflect the age-related bone mineral density and bone loss rate for postmenopausal women,and can be used for identification of patients who are likely to have osteoporosis.Otherwise,the T-score criteria of - 2.0 or below based on BMD measurements of the distal radius and ulna should be appropriate both for the diagnosis of osteoporosis and for monitoring individuals receiving antiresorptive treatment for osteoporosis.