Prevention: Environmental Factors and Behavior

Abstract

We have been studying the long-term effects of running and other vigorous physical activity upon health in a longitudinal study of 500 members of a runner's club and a similar number of community controls over the past 10 years. Average age was 58 at the onset of study. Primary end points have been mortality, disability, musculoskeletal pain, and medical care costs; we have also investigated fracture rates. In a 15% subsample we have followed lumbar bone density by CT of LI with the technique of Genant, and have followed serial x-rays of knees, hips, hands, and spine for the development of osteoarthrosis. Over time, runners develop disability at only one-fourth the rate of controls, and mortality rates are also only one-fourth as high. Musculoskeletal pain is decreased by 10% in runners, and medical care costs are reduced by 25%, despite substantial medical expenses resulting from running injuries. Fracture rates are slightly increased in runners, principally due to falls during exercise. Controls are more likely to have fractures of the hip and the spine.

Lumbar bone density initially was increased 30% in runners as compared with controls; after 8 years bone density had declined slightly in runners, but through age 70 a statistically significant 30% bone density advantage persisted in the runners, as well as in those who had stopped running but continued other vigorous physical activity. Vigorous physical activity is associated with increased bone mineral density but this advantage is not necessarily translated into lower fracture rates when all fractures are considered together. We will continue to follow these subjects as they move into the higher fracture rate age groups.

Key Words:

• exercise
• fracture prevention model
• screening