SATURDAY, Nov. 5 (HealthDay News) -- Arthritis of the knee is
striking Americans at younger ages, new research has found, but
shedding a few pounds if you're overweight may reduce your
risk.
The studies were to be presented Saturday at the American
College of Rheumatology annual meeting, in Chicago.
Nearly 6.5 million Americans between the ages of 35 and 84 will
receive a diagnosis of knee osteoarthritis in the next decade,
according to these new projections.
"The diagnosis of knee osteoarthritis is occurring much earlier," said study author Dr. Elena Losina, co-director of the Orthopedics and Arthritis Center for Outcomes Research at Brigham and Women's Hospital in Boston.
When she compared the age at diagnosis in the 1990s to ages in
the 2010s, "the average age at diagnosis has moved from 69 to 56,"
she said.
It strikes some earlier than the average age, of course. Losina
found that adults aged 45 to 54 will account for nearly 5 percent
of all knee osteoarthritis (OA) cases in the 2010s, while they
represented only 1.5 percent of the knee OA patients in the
1990s.
Losina suspects that obesity and knee injuries, both of which
have become more common in the past decade, may be helping to drive
the increase in knee OA among younger people.
Injuries to the knee have been linked with an increased risk of
knee arthritis. And certain sports are riskier than others, said
another researcher, Dr. Jeffrey Driban, an assistant professor of
rheumatology at Tufts Medical Center in Boston. He reviewed studies
that looked at a link between sports participation and knee OA. He
focused on 16 studies, and then honed in on 10 that looked at
athletes and nonathletes.
While there were not great differences later in the amount of
knee OA for former sports players and nonathletes, he did find a
risk linked with the type of sport and level of participation.
Soccer players, whether elite level or not, had a greater risk
of knee OA, he found. So did elite long-distance runners,
competitive weight lifters and wrestlers.
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 Institute of Arthritis and Musculoskeletal and
Skin Diseases. All three studies should be viewed as preliminary,
as they were presented at a medical meeting and not yet
peer-reviewed.
More information
To learn more about osteoarthritis, visit the
American College of Rheumatology.