Hip Fracture Prediction in Elderly Men and Women: Validation in the Rotterdam Study

Abstract

The aim of our study was to validate a hip fracture risk function, composed of age and femoral neck bone mineral density (BMD). This estimate of the 1-year cumulative risk was previously developed on the basis of Dutch hip fracture incidence data and BMD in men and women. A cohort of 7046 persons (2778 men) aged 55 years and over was followed for an average of 3.8 years. The 1-year hip fracture risk estimate was calculated for each participant according to the risk function and categorized as low (<0.1%), moderate (0.1 to <1%), or high (>1%). Observed first hip fracture incidence was then analyzed for each of these risk categories by age and gender. Additionally, we calculated the relative risk per standard deviation (SD) decrease in femoral neck BMD in this population. At baseline, 2360 individuals were categorized as low risk, 2567 as moderate risk, and 378 as high risk. During follow-up, 110 first hip fractures were observed corresponding to an incidence rate of 4.1/1000 person-years (pyrs) (95% confidence interval 3.4 -5.0). The observed incidence rate in the low risk group was 0.2/1000 pyrs (0.1-0.9), 2.7/1000 pyrs (1.8 -3.9) in the moderate risk group, and 18.4/1000 pyrs (12.4 -27.2) in the high risk group. Below the age of 70 years, incidence was low in all categories, and very few individuals were considered at high risk. Above the age of 70 years, the observed incidence was high in the high risk group, while in the low and moderate risk groups, the incidence remained low even over 80 years of age. In women, the age-adjusted relative risk for hip fractures was 2.5 per SD decrease in femoral neck BMD (1.8 -3.6), while in men this relative risk was 3.0 per SD (1.7-5.4). In conclusion, we observed a similar relation of hip fracture with femoral neck BMD in men and women and were able to predict accurately hip fracture rates over a period of almost 4 years. (J Bone Miner Res 1998; 13:1587-1593)

Using the same bone density reference database for men and women provides a simpler estimation of fracture risk

“…(5) Our study demonstrates that these findings are mutually compatible and demonstrable in the same cohort. The Rotterdam Study found that the rates of fracture in men and women were similar for equivalent absolute BMD, (9,20) and this has been observed in other cohorts. (8,10) The WHO coordinating center has reviewed the available data and suggested that a common (sex-independent) reference database be used for T-score generation, (4) and for the femoral neck, the recommended database is NHANES III for young white females.…”

Measurements of mobile and bound water by nuclear magnetic resonance correlate with mechanical properties of bone

“…Because of this, the concept of bone quality has emerged recognizing that fatigue microdamage, collagen integrity (crosslinking and content), and other inherent characteristics of bone tissue (besides BMD) are also important determinants of bone fracture susceptibility [2,3]. Moreover, it provides insight into why the probability of fracture increases with age, but not necessarily related to the age-related decrease in BMD [4,5]. In this study, use of Nuclear Magnetic Resonance (NMR) was explored to characterize the quality of human cortical bone tissue from two age groups.…”

Prevalent fractures are related to cortical bone geometry in young healthy men at age of peak bone mass

“…(1) Although fracture risk in old age is lower in men than in women, fracture risk is higher in boys and young men than in girls or young women. (2,3) In both young and older subjects, low areal bone mineral density (aBMD) has been associated with increased fracture prevalence, although most evidence has been obtained in women (4,5) or elderly men, (6) and only limited data are available in boys or young men. (7)(8)(9) osteoporosis, with a similar phenotype in their adult sons, providing evidence for a deficient acquisition of PBM in these men.…”