Ross P D, Wasnich R D, Vogel J M
Kuakini Medical Center, Honolulu, HI 96817.
J Bone Miner Res. 1988 Feb;3(1):1-11. doi: 10.1002/jbmr.5650030103.
Bone mineral measurements have been criticized for their inability to clearly distinguish fracture and "nonfracture" populations. However, this failure is not unexpected, since some individuals in the "nonfracture" group have low bone mass and are at increased risk but have not yet experienced fractures. Although standard radiographs are not sensitive indicators of vertebral demineralization, they do identify some of the "prefracture" osteoporotic subpopulation within the nonfracture group. Prospective follow-up of 536 Japanese-American women demonstrated that 14 new spine fractures occurred in the prefracture osteoporosis group, whereas none occurred in the nonosteoporotic group (p less than or equal to 0.03). However, bone mineral content (BMC) measurements using photon absorptiometry were much more accurate than radiographs as indicators of spine fracture risk. BMC values were somewhat higher in the prefracture group than in those with existing fractures, but values for both groups were significantly lower than in nonosteoporotic patients even after adjusting for age, height, and weight (p less than 0.0001). The magnitude of the difference was proportional to the trabecular bone content of the measurement site; the differences were greatest for the os calcis and lumbar spine, smaller for the distal radius, and least for the proximal radius. The prevalence of spinal osteoporosis (including both fracture and prefracture cases) was inversely proportional to BMC (p less than 0.0001). Again, the relations were strongest for the os calcis and lumbar spine. These results indicate that BMC measurements are valid indicators of osteoporosis status, particularly when osteoporosis is defined to include both patients with existing fractures and those at increased risk for fractures. However, dual-photon spine BMC was adversely influenced by the presence of aortic calcification, arthritis, and other disease processes (p less than or equal to 0.0001).
骨矿物质测量因其无法清晰区分骨折人群和“非骨折”人群而受到批评。然而，这种不足并不意外，因为“非骨折”组中的一些个体骨量较低且骨折风险增加，但尚未发生骨折。尽管标准X线片不是椎体脱矿的敏感指标，但它们确实能识别出非骨折组中一些“骨折前”的骨质疏松亚群。对536名日裔美国女性的前瞻性随访表明，骨折前骨质疏松组发生了14例新的脊柱骨折，而非骨质疏松组未发生骨折（p≤0.03）。然而，作为脊柱骨折风险指标，使用光子吸收法测量的骨矿物质含量（BMC）比X线片准确得多。骨折前组的BMC值略高于现有骨折患者，但即使在调整年龄、身高和体重后，两组的BMC值仍显著低于非骨质疏松患者（p＜0.0001）。差异的大小与测量部位的小梁骨含量成正比；跟骨和腰椎的差异最大，桡骨远端较小，桡骨近端最小。脊柱骨质疏松（包括骨折和骨折前病例）的患病率与BMC成反比（p＜0.0001）。同样，跟骨和腰椎的相关性最强。这些结果表明，BMC测量是骨质疏松状态的有效指标，特别是当骨质疏松定义为包括现有骨折患者和骨折风险增加的患者时。然而，双能光子脊柱BMC受到主动脉钙化、关节炎和其他疾病过程的不利影响（p≤0.0001）。
