Predictors of Imminent Risk of Nonvertebral Fracture in Older, High-Risk Women: The Framingham Osteoporosis Study

Osteoporosis treatment decisions are often based solely on BMD or on 10-year fracture risk; little is known about factors increasing imminent fracture risk. Understanding factors contributing to imminent risk of fracture is potentially useful for personalizing therapy, especially among those at high risk. Our aim was to identify predictors of nonvertebral fracture for 1- and 2-year periods in women at high risk for fracture. The Framingham Osteoporosis Study cohort included 1470 women (contributing 2778 observations), aged ≥65 years with BMD hip -score ≤ -1.0, or history of fragility fracture (irrespective of -score). Nonvertebral fractures were ascertained prospectively over 1 year and 2 years following a baseline BMD scan. Potential risk factors included age, anthropometric variables, comorbidities/medical history, cognitive function, medications, history of fracture, self-rated health, falls in the past year, smoking, physical performance, hip BMD -score, Activities of Daily Living (ADL) score, and caffeine and alcohol intakes. Predictive factors with value ≤ 0.10 in bivariate Cox proportional hazards regression models were subsequently considered in multivariable models. Mean baseline age was 75 years (SD 6.0). During 1-year follow-up, 89 nonvertebral fractures occurred; during 2-year follow-up, 176 fractures occurred. Of the variables considered in the bivariate models, significant predictors of nonvertebral fractures included age, history of fracture, self-rated health, falls in the prior year, BMD -score, ADL, renal disease, dementia, and current use of nitrates, beta-blockers, calcium channel blockers, or antidepressants. In multivariable models, significant independent risk factors were history of fracture, self-rated health, hip BMD -score, and use of nitrates. Significant 1-year results were attenuated at the 2-year follow-up. In addition to the traditional factors of BMD and fracture history, self-rated health and use of nitrates were independently associated with imminent risk of fracture in older, high-risk women. These specific risk factors thus may be useful in identifying which women to target for therapy.