Flicker L, Faulkner K G, Hopper J L, Green R M, Kaymacki B, Nowson C A, Young D, Wark J D
Department of Medicine, University of Melbourne, Parkville, Victoria, Australia. Leon_Flicker.Ger_Med/pc.unimelb.edu.au
Bone. 1996 Jan;18(1):41-5. doi: 10.1016/8756-3282(95)00418-1.
Hip axis length (HAL), a measure of femoral geometry, has been shown to predict hip fracture in white women over the age of 67 years, independently of bone mineral density at the femoral neck. A cross-sectional study of 304 pairs of female twins [176 monozygous (MZ) and 128 dizygous (DZ)], aged between 10 and 89 years, was performed to examine the influence of age, constitutional, lifestyle, and genetic factors on HAL. HAL was calculated from dual energy X-ray absorptiometry scans of the proximal femur using an automated technique with an Hologic QDR-1000W. Lean mass, fat mass, height, and weight were also measured. Maximum mean HAL was achieved by the age of 15 years. After this age there was no discernible dependency of mean HAL on age. Using within-pair differences, after adjusting for height there were no other independent constitutional or lifestyle predictors. Cross-sectionally, after adjustment for height, MZ and DZ correlations were 0.79 (95% CI: 0.73-0.84) and 0.54 (95% CI: 0.39-0.68), respectively, and independent of age. The MZ correlation exceeded the DZ correlation (p < 0.001). The best-fitting model apportioned 79% (SE 7%) of variation in height-adjusted HAL to additive genetic factors. There was marginal evidence that an environmental influence shared by twins explained 31% (SE 16%) of height-adjusted variance (p = 0.07), in which case the genetic variance was reduced to 51% (SE 15%). Adjustment for height had reduced the magnitude of total variance by 26%, and 95% of this reduction was in the additive genetic component. Applying a previously described theoretical model, approximately 10% of the increased risk of hip fracture associated with a maternal history of hip fracture could be attributed to the genetic factors determining HAL. We conclude that, in women, adult HAL is achieved by midadolescence. After adjustment for height, which is itself largely under genetic influence, other genetic factors appear to play the predominant role in explaining variation in HAL.
髋轴长度（HAL）是衡量股骨几何形态的指标，已被证明可独立于股骨颈骨密度预测67岁以上白人女性的髋部骨折。对304对年龄在10至89岁之间的女性双胞胎[176对同卵双胞胎（MZ）和128对异卵双胞胎（DZ）]进行了一项横断面研究，以检验年龄、体质、生活方式和遗传因素对HAL的影响。HAL通过使用Hologic QDR - 1000W自动化技术对近端股骨进行双能X线吸收测定扫描来计算。还测量了瘦体重、脂肪量、身高和体重。平均HAL在15岁时达到最大值。在此年龄之后，平均HAL与年龄之间没有明显的相关性。使用双胞胎对内差异，在调整身高后，没有其他独立的体质或生活方式预测因素。横断面分析中，调整身高后，MZ和DZ的相关性分别为0.79（95%可信区间：0.73 - 0.84）和0.54（95%可信区间：0.39 - 0.68），且与年龄无关。MZ的相关性超过了DZ的相关性（p < 0.001）。拟合度最佳的模型将身高调整后HAL变异的79%（标准误7%）归因于加性遗传因素。有少量证据表明双胞胎共有的环境影响解释了身高调整后方差的31%（标准误16%）（p = 0.07），在这种情况下遗传方差降至51%（标准误15%）。调整身高使总方差的幅度降低了26%，其中95%的降低发生在加性遗传成分中。应用先前描述的理论模型，与母亲有髋部骨折病史相关的髋部骨折风险增加中，约10%可归因于决定HAL的遗传因素。我们得出结论，在女性中，成年HAL在青春期中期达到。在调整身高（其本身很大程度上受遗传影响）后，其他遗传因素似乎在解释HAL变异方面起主要作用。
