The increased risk of arthritis in these participants varied from about threefold to more than sixfold compared to nonathletes, he said.
For those who already have knee OA, the best medicine may be weight loss if they are overweight, and exercise.
In another study, Dr. Stephen Messier of Wake Forest University found that a program of diet and exercise reduced pain and improved mobility by as much as 50 percent in those with knee arthritis.
He assigned adults with knee OA and pain to one of three groups for the 18-month program. One group dieted only, one group exercised only and one group did both.
In all, 399 overweight or obese men and women, average age 66, completed the study. The diet and exercise group lost the most weight, averaging 11.4 percent of their body weight. The diet-only group lost 9.5 percent; the exercise-only group lost 2.2 percent.
When they compared pain and mobility, the diet and exercise group reported much less pain and had greater walking speed than the other groups.
Driban suggested that those who want to minimize the risk of knee OA later should consider sports with a lower knee injury risk, such as swimming and cycling.
However, a sports medicine specialist took issue with that suggestion. "There is no evidence that impact sports like running causes arthritis in a healthy knee," said Dr. Stephen Nicholas, director of the Nicholas Institute of Sports Medicine and Athletic Trauma at Lenox Hill Hospital, in New York City.
Like other experts, he does agree that once a knee injury occurs, a person is at higher risk for knee arthritis.
However, if someone has a healthy knee, Nicholas said he would tell them to pick the sport they enjoy.
Losina's research was funded by the U.S. National Institutes of Health's National Inst
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