Leslie William D, Lix Lisa M, Majumdar Sumit R, Morin Suzanne N, Johansson Helena, Odén Anders, McCloskey Eugene V, Kanis John A
Department of Medicine, University of Manitoba, Winnipeg, Manitoba R3E 3P5, Canada.
Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2G3, Canada.
J Clin Endocrinol Metab. 2017 Nov 1;102(11):4242-4249. doi: 10.1210/jc.2017-01327.
Areal bone mineral density (BMD) measurements are confounded by skeletal size. Hip BMD is an input to the FRAX® tool (Centre for Metabolic Bone Diseases, University of Sheffield, United Kingdom), but it is unknown whether performance is affected by hip area.
To examine whether fracture prediction by FRAX® is affected by hip area.
Cohort study using a population-based BMD registry.
A total of 58,108 white women aged ≥40 years.
Incident major osteoporotic fracture (MOF; n = 4913) and hip fracture (n = 1369), stratified by total hip area quintile, before and after adjustment for hip axis length (HAL).
Smaller hip area was associated with younger age and lower FRAX® scores, whereas incident fractures were greater in those with larger hip area (P for trend < 0.001). Larger hip area quintile increased risk for MOF and hip fracture when adjusted for FRAX® score with BMD (P for trend < 0.001). Each standard deviation increase in hip area was associated with greater risk for incident MOF [adjusted hazard ratio (HR), 1.08; 95% confidence interval (CI), 1.05 to 1.11] and hip fracture (HR, 1.16; 95% CI, 1.11 to 1.21), but not after adjustment for HAL. FRAX® with BMD underestimated MOF risk in the largest hip area quintile and underestimated hip fracture risk in the three largest hip area quintiles.
In Canadian white women, skeletal size based on hip area affects fracture risk assessment based on FRAX® score with BMD, with risk underestimated in those with larger hip areas. Including HAL in the risk assessment compensates for this confounding by skeletal size and provides for more accurate assessment of fracture risk.
骨密度（BMD）测量会受到骨骼大小的干扰。髋部骨密度是FRAX®工具（英国谢菲尔德大学代谢性骨病中心）的一个输入参数，但髋部面积是否会影响该工具的性能尚不清楚。
研究FRAX®对骨折的预测是否受髋部面积的影响。
使用基于人群的骨密度登记系统进行队列研究。
共有58108名年龄≥40岁的白人女性。
在调整髋轴长度（HAL）前后，按全髋面积五分位数分层的新发主要骨质疏松性骨折（MOF；n = 4913）和髋部骨折（n = 1369）。
较小的髋部面积与较年轻的年龄和较低的FRAX®评分相关，而髋部面积较大者发生骨折的几率更高（趋势P<0.001）。在根据骨密度调整FRAX®评分后，较高的髋部面积五分位数会增加MOF和髋部骨折的风险（趋势P<0.001）。髋部面积每增加一个标准差，新发MOF的风险就会增加[调整后的风险比（HR），1.08；95%置信区间（CI），1.05至1.11]，髋部骨折的风险也会增加（HR，1.16；95%CI，1.11至1.21），但在调整HAL后则不然。基于骨密度的FRAX®在最大的髋部面积五分位数中低估了MOF风险，在三个最大的髋部面积五分位数中低估了髋部骨折风险。
在加拿大白人女性中，基于髋部面积的骨骼大小会影响基于FRAX®评分和骨密度的骨折风险评估，髋部面积较大者的风险被低估。在风险评估中纳入HAL可弥补骨骼大小造成的这种混杂因素，并能更准确地评估骨折风险。
