Kanis J A, Johnell O, Oden A, Jonsson B, De Laet C, Dawson A
WHO Collaborating Centre for Metabolic Bone Diseases, University of Sheffield Medical School, Sheffield, UK.
Bone. 2000 Nov;27(5):585-90. doi: 10.1016/s8756-3282(00)00381-1.
The risk of hip fracture is commonly expressed as a relative risk. The aim of this study was to examine the utility of relative risks of hip fracture in men and women using World Health Organization (WHO) diagnostic criteria for low bone mass and osteoporosis. Reference data for bone mineral density (BMD) at the femoral neck, from the third National Health and Nutrition Examination Survey (NHANES III), were applied to the population of Sweden. Relative risks (RRs) were calculated from the known relationship between BMD at the femoral neck and hip fracture risk. The apparent prevalence of low bone mass and osteoporosis depended on the segment of the young population chosen for reference ranges. Using a reference derived from women aged 20-29 years, the prevalence of osteoporosis was 21.2% in women between the ages of 50 and 84 years and 6.3% in men. The RRs associated with osteoporosis depended markedly on the risk comparison. For example, in men or women aged 50 years, the RR of hip fracture in those with osteoporosis compared to those without osteoporosis was 7.4 and 6.1, respectively. The RR of those at the threshold value for osteoporosis compared to those with an average value for BMD at that age was 6.6 and 4.6 in men and women, respectively. RRs were lower comparing those at the threshold value compared to the risk of the general population at that age (4.2 and 2.9, respectively). When RR was expressed in relation to the population risk rather than to the risk at the average value for BMD, RR decreased at all ages by 37%. Such adjustments are required for risk assessment in individuals and for the combined use of different risk factors. Because the average T score at each age decreased with age, the RR of hip fracture at any age decreased with advancing age in the presence of osteoporosis. The decrease in relative risk with age is, however, associated with an increase in absolute risk. Thus, for clinical use, the expression of absolute risks may be preferred to relative risks.
髋部骨折风险通常以相对风险表示。本研究的目的是利用世界卫生组织（WHO）低骨量和骨质疏松症的诊断标准，检验男性和女性髋部骨折相对风险的效用。来自第三次全国健康与营养检查调查（NHANES III）的股骨颈骨密度（BMD）参考数据应用于瑞典人群。相对风险（RRs）根据股骨颈骨密度与髋部骨折风险之间的已知关系计算得出。低骨量和骨质疏松症的表观患病率取决于为参考范围所选的年轻人群段。使用源自20 - 29岁女性的参考值，50至84岁女性的骨质疏松症患病率为21.2%，男性为6.3%。与骨质疏松症相关的RRs显著取决于风险比较。例如，在50岁的男性或女性中，患有骨质疏松症者与未患骨质疏松症者相比，髋部骨折的RR分别为7.4和6.1。与该年龄BMD平均值者相比，处于骨质疏松症阈值者的RR在男性和女性中分别为6.6和4.6。与该年龄一般人群的风险相比，处于阈值者的RR较低（分别为4.2和2.9）。当RR相对于人群风险而非BMD平均值的风险表示时，各年龄段的RR均降低37%。个体风险评估以及不同风险因素的联合使用需要进行此类调整。由于各年龄的平均T值随年龄降低，在存在骨质疏松症的情况下，任何年龄的髋部骨折RR随年龄增长而降低。然而，相对风险随年龄的降低与绝对风险的增加相关。因此，对于临床应用，绝对风险的表达可能比相对风险更可取。
