Increased falling as a risk factor for fracture among older women: the study of osteoporotic fractures.

More frequent falling is associated with a higher risk of fracture among older women, but it is not known whether an increased rate of falling, independent of the average rate, also increases fracture risk. The authors examined the relation between an increase in the rate of falls during the first 4 years of follow-up and the subsequent fracture rate, reported for a median of 6.3 years (1986-1998), in 9,106 US women aged 65 years or more. Women in the upper quartile of increasing falls (>0.44 falls/year/year) had greater risks of subsequent hip fracture (rate ratio = 1.42, 95% confidence interval: 0.99, 2.04) and fracture of the proximal humerus (rate ratio = 1.79, 95% confidence interval: 1.08, 2.95) than women without an increase in falls, after adjustment for age, average rate of falls over 4 years, and known risk factors for fracture. Risks of distal forearm, ankle, or foot fracture were not elevated. The associations between fracture risk and increasing falls were not accounted for by baseline physical or cognitive function. An increase in the rate of falls, independent of the average rate, may be associated with a higher risk of frailty (hip and proximal humerus) fractures but not fractures at other sites.