Identification of high-risk individuals for hip fracture: a 14-year prospective study

Abstract

In this 14-year prospective study, men and women were found to share a common set of risk factors for hip fracture: low BMD, postural instability and/or quadriceps weakness, a history of falls, and prior fracture. The combination of these risk factors accounted for 57% and 37% of hip fractures in women and men, respectively.

Introduction: Risk factors for hip fracture, including low BMD, identified in women, have not been shown to be useful in men. It is also not known whether fall-related factors (muscle strength and postural instability) predict hip fracture. This study examined the association between falls-related factors and hip fractures in elderly men and women.

Materials and methods: This is an epidemiologic, community-based prospective study, which included 960 women and 689 men > or = 60 years of age who have been followed for a median of 12 years (interquartile range, 6-13). The number of person-years was 9961 for women and 4463 for men. The outcome measure was incidence of hip fracture. Risk factors were femoral neck BMD (FNBMD), postural sway, quadriceps strength, prior fracture, and fall.

Results: Between 1989 and 2003, 115 (86 women) sustained a hip fracture. The risk of hip fracture (as measured by hazards ratio [HR]) was increased by 3.6-fold (95% CI: 2.6-4.5) in women and 3.4-fold (95% CI: 2.5-4.6) in men for each SD (0.12 g/cm2) reduction in FNBMD. After adjusting for BMD, the risk of hip fracture was also increased in individuals with the highest tertile of postural sway (HR: 2.7; 95% CI: 1.6-4.5) and low tertiles of quadriceps strength (HR: 3.0; 95% CI: 1.3-6.8). Furthermore, a history of fall during the preceding 12 months and a history of fracture were independent predictors of hip fracture. For each level of BMD, the risk of hip fracture increased linearly with the number of non-BMD risk factors. Approximately 57% and 37% of hip fracture cases in women and men, respectively, were attributable to the presence of risk factors, osteoporosis (BMD T score < or = -2.5), and advancing age.

Conclusions: Men and women had a common set of risk factors for hip fracture: low BMD, postural instability and/or quadriceps weakness, a history of falls, and prior fracture. Preventive strategies should simultaneously target reducing falls and improvement of bone strength in both men and women.