to the editor: As a runner and a physician who recommends regular exercise to his patients, I read with particular interest the “ Clinical Evidence Handbook” on osteoarthritis of the hip. I struggle with the question of whether running long distances is likely to increase, decrease, or have no effect on osteoarthritis of the hip.

The article makes seemingly contradictory statements in that there is moderate evidence for a positive association between osteoarthritis of the hip and running, but also that “only limited evidence exists for a positive association between the occurrence of osteoarthritis of the hip and participation in athletics.”

A recent prospective study did not show an increase in osteoarthritis of the knee among distance runners, although the study did not evaluate the hip.¹ The literature asserts that running does not increase the risk of osteoarthritis. Although not a peer-reviewed journal, Runner's World often quotes literature citing the benefits of running in maintaining joint health.² Weight control probably is a major factor.

Marathon running continues to expand in the United States, with 468,000 marathon finishers in 2009.³ I believe there is a tendency for physicians to discourage this activity because of a long-standing belief that it is a traumatic sport. However, it may be that distance running actually promotes joint health by controlling weight. Perhaps Dr. Scott could clarify the evidence related to distance running and its effect on osteoarthritis. I would appreciate further discussion or insight into this issue.