Risk of Subsequent Fracture After Low-Trauma Fracture in Men and Women

To examine long-term risk of subsequent fracture following initial osteoporotic fracture in men and women. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study (Dubbo Osteoporosis Epidemiology Study) in Australia of 2245 community-dwelling women and 1760 men aged 60 years or older followed up for 16 years from July 1989 through April 2005. MAIN OUTCOME MEASURE: Incidence of first (initial) fracture and incidence of subsequent fracture according to sex, age group, and time since first fracture. Relative risk was determined by comparing risk of subsequent fracture with risk of initial fracture.

There were 905 women and 337 men with an initial fracture, of whom 253 women and 71 men experienced a subsequent fracture. Relative risk (RR) of subsequent fracture in women was 1.95 (95% confidence interval [CI], 1.70-2.25) and in men was 3.47 (95% CI, 2.68-4.48). As a result, absolute risk of subsequent fracture was similar in women and men and at least as great as the initial fracture risk for a woman 10 years older. Thus, women and men aged 60 to 69 years had absolute refracture rates of 36/1000 person-years (95% CI, 26-48/1000) and 37/1000 person-years (95% CI, 23-59/1000), respectively. The increase in absolute fracture risk remained for up to 10 years, by which time 40% to 60% of surviving women and men experienced a subsequent fracture. All fracture locations apart from rib (men) and ankle (women) resulted in increased subsequent fracture risk, with highest RRs following hip (RR, 9.97; 95% CI, 1.38-71.98) and clinical vertebral (RR, 15.12; 95% CI, 6.06-37.69) fractures in younger men. In multivariate analyses, femoral neck bone mineral density, age, and smoking were predictors of subsequent fracture in women and femoral neck bone mineral density, physical activity, and calcium intake were predictors in men.