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

Authors

  • Chris E. D. H. De Laet,

    1. Department of Epidemiology & Biostatistics, Erasmus University Medical School, Rotterdam, The Netherlands
    2. Institute for Medical Technology Assessment, Erasmus University Rotterdam, The Netherlands
    Search for more papers by this author
  • Ben A. Van Hout,

    1. Institute for Medical Technology Assessment, Erasmus University Rotterdam, The Netherlands
    Search for more papers by this author
  • Huibert Burger,

    1. Department of Epidemiology & Biostatistics, Erasmus University Medical School, Rotterdam, The Netherlands
    2. Department of Internal Medicine III, Erasmus University Medical School, Rotterdam, The Netherlands
    Search for more papers by this author
  • Angelique E. A. M. Weel,

    1. Department of Epidemiology & Biostatistics, Erasmus University Medical School, Rotterdam, The Netherlands
    2. Department of Internal Medicine III, Erasmus University Medical School, Rotterdam, The Netherlands
    Search for more papers by this author
  • Albert Hofman,

    1. Department of Epidemiology & Biostatistics, Erasmus University Medical School, Rotterdam, The Netherlands
    Search for more papers by this author
  • Huibert A. P. Pols

    Corresponding author
    1. Department of Epidemiology & Biostatistics, Erasmus University Medical School, Rotterdam, The Netherlands
    2. Department of Internal Medicine III, Erasmus University Medical School, Rotterdam, The Netherlands
    • Address reprint requests to: Dr. Huibert A.P. Pols, Department of Internal Medicine III, Erasmus University Medical School, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands
    Search for more papers by this author

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.

Ancillary