前臂骨骨密度测定诊断骨质疏松标准的研究

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

目的探讨女性前臂骨骨量的年龄分布规律,为建立周围骨骨密度的骨质疏松诊断标准积累数据。方法采用美国NORLAND-Stratec周围型双能X线骨矿测量仪(pDXA)测量了452名20～79岁女性健康志愿者非优势侧前臂远端桡骨和尺骨(distal radius+ulna)、近端桡骨和尺骨(proximal radius+ulna)以及近端桡骨(proximal radius)的BMD值,以问卷调查方法收集研究对象的一般情况,分析前臂骨不同测量部位BMD变化的年龄分布规律。结果前臂骨不同测量部位的BMD数据均符合正态分布规律。健康女性峰值骨密度出现在40～44岁年龄段,此后随年龄增加而下降,在50～59岁和70岁以上年龄段出现快速骨丢失,尤其是前臂远端骨丢失速率较快,55～59岁年龄段女性骨累积丢失率达25%,与DXA测定中轴骨的骨量丢失规律一致。前臂远端桡+尺骨的骨质疏松(OP)检出率较高,是围绝经期妇女OP检出的敏感部位。50～54岁年龄段女性低骨量发生率为57.6%,骨质疏松的发生率为25.8%(以低于PBM-2.0s为诊断标准)和12.1%(以低于PBM-2.5s为诊断标准);55～59岁年龄段女性低骨量发生率上升至80.9%,骨质疏松的发生率上升至50.0%和30.9%。60岁以后,低骨量和骨质疏松发生率的增加速度趋缓,但70岁以后低骨量和骨质疏松的发生率再次上升。结论前臂骨骼BMD测定可以作为骨质疏松高危人群筛查的有效工具。将前臂远端桡+尺骨为BMD主要检测部位,以低于PBM-2.0s为骨质疏松诊断标准,是筛查骨质疏松人群和评估干预措施较适宜的标准。

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.