Date Published: June 19, 2007
Publisher: Public Library of Science
Author(s): Harri Sievänen, Pekka Kannus
Abstract: The authors discuss a new study, with a 35 year follow up, showing that exercise reduces the risk of fragility fractures in men.
Partial Text: From an evolutionary perspective, we were born to run . Indeed, the human musculoskeletal system is a fine locomotive apparatus that can adapt to varying demands. Our bones and muscles have the inborn ability to modify their structural and material designs to accommodate additional loads. Present-day athletes, for example, show higher bone mass and more robust structure than nonathletes at loaded bone sites .
The best way to prove that physical activity prevents fragility fractures would be to conduct several adequately powered randomized controlled trials. But such trials are almost impossible to do for methodological reasons, such as problems with study size, compliance, drop-outs, blinding, and long-term follow-up . But there is evidence from several prospective observational cohort studies that physical activity is associated with a reduced risk of fragility fracture [9–12]. A 2002 study of postmenopausal women by Feskanich et al.  found a dose-response relationship: the risk of hip fracture was lowered by 6% for each increase of three metabolic equivalent hours of activity per week (equivalent to one hour per week of walking at an average speed).
Fractures can always happen, but the two studies by Feskanich et al.  and Michaëlsson et al.  show that the risk of fragility fractures can be reduced by regular physical activity. According to Michaëlsson and colleagues’ estimation of population-attributable risk, one-third of all hip fractures could be avoided if men engaged in adequate amounts of physical activity , a result that is fully concordant with a similar analysis in women . These data cannot be ignored by public health professionals and policymakers. Substantial efforts should be put into promoting physical activity in the population at large.