Predictors of falls among postmenopausal women: results from the National Osteoporosis Risk Assessment (NORA)

Using data from 66,134 postmenopausal women enrolled in the National Osteoporosis Risk Assessment (NORA) study, more than half of whom were less than age 65, we identified 18 risk factors that independently predicted a significantly increased risk of falling and observed a graded increase in risk with an increasing number of risk factors. This study was designed to identify predictors of falls in a large prospective study of community-dwelling, postmenopausal women, 58% of whom were less than 65 years old at baseline. We exclusively used survey data from 66,134 NORA participants who completed the baseline survey and three follow-up surveys over 6 years. Stepwise logistic regression was used to select potential fall predictors. A simple fall risk index was created by giving one point to each significant independent risk factor. More than one third (38.2%) of participants reported at least one fall since baseline. The largest predictor of fall risk was history of falls (odds ratio [OR] = 2.7). In the multivariate analysis, 17 additional risk factors were significantly associated with incident falls (but with smaller OR), including age, college education, poor hearing, diabetes, personal or family history of fracture, hypothyroidism, and height loss. Of the 3,346 women with zero fall risk factors, 22.6% reported falling compared to 84.3% of the 51 women with a parts per thousand yen11 risk factors. This large cohort had sufficient power to identify 18 risk factors that independently predicted a significantly increased risk of falling with a graded increase in risk with increasing number of risk factors.