Exercise Won't Up Knee Arthritis Risk
Study Shows Activity Didn't Hurt Healthy Knees of Older Exercisers
Jan. 31, 2007 -- Moderate exercise doesn't increase the risk of developing
arthritis in the knees of older adults, even if they are overweight, according
to a new study that evaluated more than 1,200 people.
"There really was no difference between those who exercised and those
who didn't in terms of getting knee osteoarthritis," says researcher David
T. Felson, MD, MPH, professor of medicine and epidemiology at Boston
Over the nine-year study period, exercise didn't raise or lower the risk of
getting knee arthritis, he says.
His study, as well as another review study and an editorial, are published
online and in the Feb. 15 issue of Arthritis & Rheumatism.
Felson and his colleagues questioned more than 1,200 men and women who
participated in the Framingham Offspring cohort, including children of
participants in the original Framingham Study, which has looked at
cardiovascular disease risks since 1948.
At the beginning of the arthritis study, the average age of participants was
53. In 1993-1994, Felson's team gave them knee X-rays and questioned them about
any pain, aching, or stiffness in the knees. Most subjects reported that they
walked for exercise; only 68 jogged or ran.
Felson divided participants into three groups: sedentary, those who walked
six or more miles weekly, and those who walked less than six miles a week for
The researchers began to conduct follow-up exams in 2002, taking additional
knee X-rays and asking again about knee symptoms. Weight was recorded at the
start and at the final follow-up, when specialists read the X-rays to look for
evidence of arthritis.
On average, the participants' body mass index or BMI was 27.4; below 25 down
to 18.5 is deemed normal weight; 25 to 29.9 is considered overweight.
Among those who did no exercise, 7.5% got knee arthritis with symptoms over
the course of the study; 4.9% of those who walked less than 6 miles a week also
got knee arthritis with symptoms, along with 6.4% of those who walked 6 or more
miles a week. To a scientist, Felson says, those differences are not
"I personally had thought there would be some risk," Felson says.
"A lot of these people were very overweight." Obesity is a risk factor
for getting knee osteoarthritis, other research has shown.
Arthritis Risk and Healthy Knees
"This is another study that furthers our belief that moderate physical
activity does not increase the risk of knee osteoarthritis," says Marian A.
Minor, PhD, professor and chairwoman of physical therapy at the University of
Missouri at Columbia, who wrote an editorial to accompany the study.
She cautions, however, that "the study results apply to healthy
In the same issue, a review of 37 published studies, conducted
by researchers from Erasmus Medical Center in Rotterdam, Netherlands, showed
regular sports activities are not related to getting arthritis in the knee.
They didn't find a link, either, between knee pain, knee injury, and later
arthritis in the joint.