Risk factors for falls and for serious injuries on falling among older Japanese women in Hawaii

OBJECTIVES: To evaluate if similar constellations of factors underlie the risks of falls and injuries on falling for Japanese women as reported for predominately white populations. DESIGN: A prospective cohort study SETTING: The island of Oahu PARTICIPANTS: The older Japanese women who participated in the Hawaii Osteoporosis Study (mean age = 74 +/- 5 (SD) years). MEASUREMENTS:As outcomes: falls and serious injuries on falling. As predictors: anthropometric measurements, measurements of neuromuscular performance, activities of daily living (ADLs), past falls, and other suspected risk factors for falls and serious injuries. RESULTS: In multivariable models, four subject characteristics were positively associated with having a fall (having a fall in the past year (RR = 2.0 (95% CI, 1.5-2.8)), slow chair stands (RR = 1.4 (95% CI, 1.0-1.9), a short height (RR = 1.5 (95% CI, 1.1-2.1)), difficulties with five or more ADLs (RR = 1.5 (95% CI, 1.1-2.1))). Two subject characteristics were negatively associated with having a fall (ability to perform a full. tandem balance with eyes closed (RR = .7 (95% CI, .5-1.0)) and having a long functional reach (RR = .7 (95% CI,.5-1.0))). The RRs represent as nearly as possible comparisons of the upper (or lower) quartile and the remaining quartiles. In multivariable models, long times for chair stands (odds ratio (OR) = 3.0 (95% CI, 1.5-6.1)) and a low BMI (OR = 3.1 (95% CI, 1.5-6.4)) were positively associated with having a serious injury among women who had a fall. Among the same women, taking part in an activity they did frequently (OR = .3 (95% CI, .1-.8)) and slow foot reaction times (OR = .3 (95% CI, .1-.8)) were associated negatively with having a serious injury. CONCLUSIONS: The results from this Japanese cohort support the conclusion that women at high risk of falling and serious fall injuries can be identified using a questionnaire and simple, performance-based tests of neuromuscular function. The risk factors for falling overlapped, but were distinct from, those for suffering a serious injury once a fall had occurred.