Leisure-time physical activity levels and changes in relation to risk of hip fracture in men and women

The authors prospectively studied the effect of leisure-time physical activ ity level on hip fracture risk along with the influence of within-subject c hanges in activity levels, while taking possible confounding by other healt h behaviors and poor health into account. Analyses were based on pooled dat a from three population studies conducted in Copenhagen, Denmark. Among 13, 183 women and 17,045 men, 1,121 first hip fractures were identified during follow-up. In comparison with being sedentary, the relative risk (RR) of hi p fracture associated with being moderately physically active 2-4 hours per week was 0.72 (95% confidence interval (CI): 0.59, 0.89) in women and 0.75 (95% CI: 0.55, 1.03) in men after adjustment for confounders. Being in the most active leisure activity category did not decrease the risk of hip fra cture further. Adjustment for poor health affected the risk estimates only modestly. Subjects who, during follow-up, reduced their physical activity l evel from the highest or the intermediate activity level to a sedentary lev el had a higher risk of hip fracture than did those who remained moderately physically active at the intermediate level (multivariate adjusted RR = 2. 19, 95% CI: 1.00, 4.84 and RR = 1.89, 95% CI: 1.21, 2.95, for reduction fro m the highest and intermediate levels, respectively), There was no evidence of a fracture-protective effect from increasing physical activity. In conc lusion, moderate levels of physical activity appear to provide protection a gainst later hip fracture, Decline in the physical activity level over time is an important risk factor for hip fracture.