Active Men Lessen Later Fracture Risk

UPPSALA, Sweden, June 19 -- Osteoporotic fracture may be less common among men than women, but a lifetime of physical activity appears to be just as important in reducing this risk, researchers found.
Fragility hip fractures were more than twice as common among men who reported little recreational exercise during 35 years of follow-up as among those who participated in sports at least three hours a week, found Karl Michaëlsson, M.D., Ph.D., of University Hospital here, and colleagues in a longitudinal study.
One-third of all hip fractures among men could be prevented by regular participation in sports, they wrote online in the journal PLoS Medicine.
This finding "is fully concordant with a similar analysis in women," noted Harri Sievänen, Ph.D., and Pekka Kannus, M.D., Ph.D., both of the UKK Institute in Tampere, Finland, in an accompanying editorial.
For postmenopausal women, moderate exercise has been shown to substantially lower hip fracture risk. For men, though, prospective observational studies have had inconsistent results.
"Given these inconsistent findings, the results … represent an important advance," Drs. Sievänen and Kannus wrote.
Dr. Michaëlsson and colleagues analyzed the physical activity component of the Uppsala Longitudinal Study of Adult Men, which surveyed 2,205 men in the city who were ages 49 to 51 when the study began in the early 1970s.
At baseline and at age 60, 70, 77, and 82 the participants completed questionnaires asking about how they spent their leisure time.
Half reported that they engaged in active sports or heavy gardening for at least three hours a week, or regularly engaged in hard physical training or competitive sports, collectively defined as high physical activity.
Another 36.4% were included in the intermediate activity category for responding that they "often" went walking or cycling for pleasure.
Only 14.7% reported spending their leisure time in mostly sedentary activities.
The men were followed for fracture using Sweden's national Hospital Discharge Register and local hospital registers and records.
During the 35-year follow-up, 482 men (22%) experienced a fracture of some type and 134 (6%) had a hip fracture.
For the three groups of men from high to low activity, the findings were:
Absolute incidence of hip fracture over the 35 years increased with less active lifestyles (20.5%, 13.3%, and 8.4%).
Hip fracture was significantly more likely among sedentary men than among those who were highly active (adjusted hazard ratio 2.56, 95% confidence interval 1.55 to 4.24) and among those with a medium activity level (HR 1.61, 95% CI 1.10 to 2.36).
Any type fracture occurred among 30.2%, 33.3%, and 43.6% of the men grouped by physical activity level, respectively, during the study.
Overall fracture risk was also significantly elevated for sedentary men compared with those with a high activity level (adjusted HR 1.57, 95% CI 1.20 to 2.07).
Men whose physical activity changed over time in the study had an intermediate risk of hip fractures.
Compared with men who maintained high physical activity, the adjusted hip fracture hazard ratio was 2.31 for those with a consistently low or medium physical activity level, 1.94 for those whose activity decreased from high to medium or from high to low, and 1.50 for those who increased from low or medium activity to high activity.
Relatively few participants reported hard physical training, but this group did not appear to gain additional protection against hip fracture compared with those who reported a high activity level (adjusted HR 0.94, 95% CI 0.34 to 2.63) or against fractures overall (adjusted HR 1.16, 95% CI 0.74 to 1.83).
Physical activity at work was not associated with fracture risk, the researchers said, although they did not present this data. Nor did it affect estimates of recreational physical activity, they said.
Based on an analysis of the population-attributable risk, the researchers estimated that about one-third of all hip fractures could have been prevented if all men maintained a high physical activity level (adjusted estimate 34%, 95% CI 14% to 50%).
"We suggest that older men should increase their leisure physical activity to reduce their risk of osteoporotic fractures," Dr. Michaëlsson and colleagues wrote, particularly because increasing activity in later life lowered risk.
The mechanisms by which activity reduces fracture risk are likely related to muscle performance and balance and bone structure and strength, the researchers noted.
Fractures caused by falls among aging people "have become a serious public health problem for our modern societies, so there is great interest in finding preventive strategies," Drs. Sievänen and Kannus wrote.
"Regular exercise is undoubtedly one of the most promising preventive options," the editorialists wrote.
However, further study is needed to define the best type, intensity, frequency, and duration of activity for different target populations, they added.
The study was supported by the Swedish Research Council. The researchers reported no competing interests. The editorialists reported no conflicts of interest. Additional source: Public Library of Science MedicineSource reference: Sievänen H, Kannus P "Physical activity reduces the risk of fragility fracture" PLoS Med 2007;4:e222. Additional source: Public Library of Science MedicineSource reference: Michaelsson K, et al "Leisure physical activity and the risk of fracture in men" PLoS Med 2007;4:e199.