Leisure-Time Physical Activity and Risk of Fracture: A Cohort Study of 66,940 Men and Women.

Physical activity has been associated with reduced risk of fracture, but it is not known how the intensity or frequency of physical activity influences this risk reduction. We aim to compare the risk of hip fracture and fracture of any locale between men and women with different levels of leisure-time walking/bicycling and exercise. A total of 37,238 women (born 1914-1948) from the Swedish Mammography Cohort and 45,906 men (born 1918-1952) from the Cohort of Swedish Men were followed for a maximum of 17 years. Exposure and covariate information was collected through a self-administered questionnaire in 1997. Incident fractures (5153 individuals with hip fracture and 15,043 with any type of fracture) and comorbidities were gathered from national and local patient registries. Hazard ratios (HRs) were calculated using Cox proportional hazards regression. Individuals who walked/bicycled less than 20 minutes per day had a lower rate of hip fracture (multivariable adjusted HR = 0.77; 95% confidence interval [CI] 0.70 to 0.85) and any fracture (HR = 0.87; 95% CI 0.82 to 0.92) compared with those who hardly ever walked/bicycled. These reduced rates were also evident in both sexes, in different age categories, for vertebral fractures and for non-hip, non-vertebral fractures. Those who reported exercise 1 hour per week had a lower rate of hip fracture (HR = 0.87; 95% CI 0.80 to 0.96) and any fracture (HR = 0.94; 95% CI 0.89 to 0.99) compared with those who exercised less than 1 hour per week. Only minor differences in HRs were observed in individuals with moderate compared with higher levels of walking/bicycling or exercise. Walking/bicycling and exercise showed almost equal reductions in rate of fracture when compared with those in a joint category with lowest activity. In conclusion, both moderate and high self-reported frequency of physical activity is associated with reduced future risk of fracture.