Pasco J A, Seeman E, Henry M J, Merriman E N, Nicholson G C, Kotowicz M A
Department of Clinical and Biomedical Sciences, Barwon Health, The Geelong Hospital, The University of Melbourne, P.O. Box 281, Geelong 3220, Australia.
Osteoporos Int. 2006;17(9):1404-9. doi: 10.1007/s00198-006-0135-9. Epub 2006 May 13.
Osteoporosis is associated with increased risk for fracture. However, most postmenopausal women have bone mineral density (BMD) within the normal or osteopenic range. The aim of this study was to determine the proportion of the population burden of fragility fractures arising from women at modest risk for fracture.
We measured baseline BMD in a population-based random sample of 616 postmenopausal women aged 60-94 years and followed these individuals for a median of 5.6 years (IQR 3.9-6.5) to determine the incidence of fractures according to age, BMD and the presence of a prior fracture.
Based on WHO criteria, 37.6% of the women had normal total hip BMD, 48.0% had osteopenia and 14.5% had osteoporosis. The incidence of fracture during follow-up was highest in women with osteoporosis, but only 26.9% of all fractures arose from this group; 73.1% occurred in women without osteoporosis (56.5% in women with osteopenia, 16.6% in women with normal BMD). Decreasing BMD, increasing age and prior fracture contributed independently to increased fracture risk; in a multivariate model, the relative risk for fracture increased 65% for each SD decrease in BMD (RR=1.65, 95%CI 1.32-2.05), increased 3% for every year of age (RR=1.03, 95%CI 1.01-1.06) and doubled with prevalent fracture (RR=2.01, 95% CI 1.40-2.88). A prevalent fracture increased the risk for fractures such that women with osteopenia and prevalent fracture had the same, if not greater, risk as women with osteoporosis alone.
Reducing the population burden of fractures requires attention to women with osteopenia, as well as osteoporosis, because over half of the fragility fractures in the population arise in these individuals, and women with osteopenia plus a prevalent fracture have the same fracture risk as women with osteoporosis.
骨质疏松症与骨折风险增加相关。然而，大多数绝经后女性的骨密度（BMD）处于正常或骨量减少范围内。本研究的目的是确定骨折风险中等的女性在脆性骨折人群负担中所占的比例。
我们对616名年龄在60 - 94岁的绝经后女性进行了基于人群的随机抽样，测量其基线骨密度，并对这些个体进行了为期5.6年的中位数随访（四分位间距3.9 - 6.5年），以根据年龄、骨密度和既往骨折情况确定骨折发生率。
根据世界卫生组织标准，37.6%的女性全髋骨密度正常，48.0%骨量减少，14.5%患有骨质疏松症。随访期间骨折发生率在骨质疏松症女性中最高，但所有骨折中只有26.9%源于该组；73.1%发生在无骨质疏松症的女性中（骨量减少女性中占56.5%，骨密度正常女性中占16.6%）。骨密度降低、年龄增加和既往骨折均独立导致骨折风险增加；在多变量模型中，骨密度每降低1个标准差，骨折相对风险增加65%（RR = 1.65，95%CI 1.32 - 2.05），年龄每增加1岁，骨折相对风险增加3%（RR = 1.03，95%CI 1.01 - 1.06），既往骨折时骨折风险翻倍（RR = 2.01，95%CI 1.40 - 2.88）。既往骨折会增加骨折风险，使得骨量减少且有既往骨折的女性即使不比仅患有骨质疏松症的女性风险更高，至少也与她们相同。
减轻骨折的人群负担需要关注骨量减少以及患有骨质疏松症的女性，因为人群中超过一半的脆性骨折发生在这些个体中，且骨量减少并有既往骨折的女性与患有骨质疏松症的女性具有相同的骨折风险。
