HIP FRACTURE PREDICTION IN ELDERLY MEN AND WOMEN - VALIDATION IN THE ROTTERDAM STUDY

The aim of our study was to validate a hip fracture risk function, com posed of age and femoral neck bone mineral density (BMD). This estimat e 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 cohor t of 7046 persons (2778 men) aged 55 years and over was followed for a n average of 3.8 years. The 1-year hip fracture risk estimate was calc ulated for each participant according to the risk function and categor ized as low (<0.1%), moderate (0.1 to <1%), or high (greater than or e qual to 1%). Observed first hip fracture incidence was then analyzed f or each of these risk categories by age and gender. Additionally, we c alculated the relative risk per standard deviation (SD) decrease in fe moral neck BMD in this population. At baseline, 2360 individuals were categorized as low risk, 2567 as moderate risk, and 378 as high risk D uring follow-up, 110 first hip fractures were observed corresponding t o an incidence rate of 4.1/1000 person-years (pyrs) (95% confidence in terval 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 pars (12.4-27.2) in the high risk group. Below t he 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, th e observed incidence was high in the high risk group, while in the low and moderate risk groups, the incidence remained low even over 80 yea rs 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 th is 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 wo men and were able to predict accurately hip fracture rates over a peri od of almost 4 years.