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Abstract: A large body of epidemiological evidence suggests an inverse relationship between physical activity and risk of fractures. However, it is unclear how this association varies according to the domain of life in which the activity is undertaken. In this analysis of the European Prospective Investigation of Cancer-Norfolk study, we assessed total and domain-specific physical activity using a validated questionnaire (EPAQ2) in 14,903 participants (6514 men, mean age 62year) who also underwent quantitative ultrasound of the heel. After a median follow-up of 7.5years, there were 504 fractures of which 164 were hip fractures. In multivariable linear regression analysis, broadband ultrasound attenuation (BUA) was positively associated with total and leisure-time activities while showing no association with transportation and work activities. Home activities were associated with a lower BUA among younger participants. In multivariable Cox proportional-hazards models, moderate activities at home and in leisure time were associated with lower hip fracture risk among women (hazard ratios [HR] 0.51 and 0.55, p value 0.02 and 0.03, respectively). Among men, leisure-time activities were associated with lower risk of hip fracture (HR=0.58; p for trend<0.001) whereas activities at home were associated with higher risk of any fracture (HR=1.25; p for trend=0.008). Walking for leisure or transport was associated with lower risk of fracture in both men and women. Multivariable fractional polynomial modelling showed a U-shaped association between home activities and fracture risk especially among women. This study suggests that different domains of physical activity may relate differently to fracture risk and these relationships may vary by sex. [ABSTRACT FROM AUTHOR]

Abstract: The role of quantitative ultrasound (QUS) in clinical practice is debatable. An unanswered question is that whether combining QUS and BMD measurements could improve the prediction of fracture risk. We examined this in a sample of men and women in the European Prospective Investigation into Cancer (EPIC)-Norfolk who had both heel QUS and hip DXA between 1995 and 1997 and were followed for any incident fracture up to 2007. From 1455 participants (703 men) aged 65–76 years at baseline, 79 developed a fracture over 10.3±1.4 years of follow-up. Two separate sex-stratified Cox proportional-hazard models were used including clinical risk factors and total hip BMD. Heel broadband ultrasound attenuation (BUA) was also included in the second model. Global measures of model fit, area under ROC curve, and the Hosmer–Lemeshow statistic showed relative superiority of the model including BUA. Using each model, we calculated 10-year absolute risk of fracture for all participants and categorized them in groups of <5%, 5% to <15%, and ≥15%. Comparison of groupings showed a total re-classification of 16.6% of participants after inclusion of BUA with the greatest re-classification (30.7%) among the group with intermediate risk. Adding a QUS measurement to models based on clinical risk factors and BMD improves the predictive power of models and suggests that further attention should be paid to QUS as a clinical tool for fracture risk assessment. [Copyright &y& Elsevier]

Purpose: Physical activity helps maintain mobility, physical functioning, bone mineral density (BMD), muscle strength, balance and, therefore, may help prevent falls and fractures among the elderly. Meanwhile, it is theoretically possible that physical activity increases risk of fractures as it may increase risk of falls and has only a modest effect on BMD. This review aims to assess the potential causal association between physical activity and osteoporotic fractures from an epidemiological viewpoint. Methods: As the medical literature lacks direct evidence from randomized controlled trials (RCTs) with fracture end points, a meta-analysis of 13 prospective cohort studies with hip fracture end point is presented. The current evidence base regarding the link between exercise and fracture risk determinants (namely, falls, BMD, and bone quality) are also summarized. Results: Moderate-to-vigorous physical activity is associated with a hip fracture risk reduction of 45% (95% CI, 31-56%) and 38% (95% CI, 31-44%), respectively, among men and women. Risk of falling is suggested to be generally reduced among physically active people with a potential increased risk in the most active and inactive people. Positive effects of physical activity on BMD and bone quality are of a questionable magnitude for reduction of fracture risk. Conclusion: The complexity of relationship between physical activity and osteoporotic fractures points out to the need for RCTs to be conducted with fractures as the primary end point. [Copyright &y& Elsevier]