Researchers examined data on 240 obese adults with pain from knee
osteoarthritis who were participating in an 18-month experiment to
see how diet alone or combined with exercise might impact their
Participants who lost 10 percent or more of their weight by the end
of the study experienced a 50 percent reduction in pain and also
reported significant improvements in mobility and daily function.
But more weight loss was even better. People who lost at least 20
percent of their weight experienced 25 percent less pain and better
daily function than patients who lost no more than 10 percent of
their weight, the study found.
"Our previous work has shown that when combined with mild to
moderate exercise, a 5 percent weight loss over 18 months reduces
pain by 25 percent and improves function and mobility compared to a
control group," said lead study author Stephen Messier of Wake
Forest University in Winston-Salem, North Carolina.
"Twice that weight loss to 10 percent essentially has twice the
effect," Messier said by email. "Our new study indicates that for
people who achieve a 10 percent weight loss and would like to
continue losing more weight safely, they will see additional
benefits in improved health-related quality of life, and reduced
pain and improved function."
Osteoarthritis is the most common joint disease in the U.S.,
affecting more than half of elderly adults. Compared with people at
normal weight, obese individuals are much more likely to develop the
condition and experience pain related to this joint damage.
The current study also looked at results from six-minute walking
tests and found more weight loss associated with longer distances in
the test. Patients had some improvement in walking distance when
they lost just 5 percent of their weight, but results were much more
dramatic with a 10 percent or 20 percent weight loss.
One limitation of the study is that it doesn't show long-term
effects of weight loss on knee joint pain or mobility, or show
whether people are able to maintain weight loss over time or if they
regain weight. It also wasn't a controlled experiment designed to
prove how the magnitude of weight loss might directly influence
reductions in pain or improvements in mobility.
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"Carrying extra weight puts a lot of strain on weight-bearing joints
while standing, particularly the knees, because overweight and obese
individuals simply have more body mass for gravity to pull toward
the ground," said Burel Goodin, a researcher at the University of
Alabama at Birmingham who wasn't involved in the study.
"The result of weight loss is less pressure on the knees, which then
often means less pain in the knee joint and an easier time moving
around," Goodin said by email. "Diet and exercise are likely going
to be the most helpful for losing the weight, but it is the weight
loss itself that spares the knee joints."
In addition to reducing the biomechanical strain on the knee joint,
weight loss may also help curb pain from knee osteoarthritis by
decreasing inflammation, said Dr. C. Kent Kwoh, director of the
University of Arizona Arthritis Center in Tucson.
"The simple message is that some weight loss is good, even just 10
percent, and more weight loss is even better for all these important
parameters of symptoms, function, joint load and systemic
inflammation," Kwoh, who wasn't involved in the study, said by
While it's possible to lose weight without physical activity, adding
exercise to a weight loss program may help people achieve more
lasting results in terms of reducing pain from knee osteoarthritis,
said Anita Wluka, a researcher at Monash University in Australia who
wasn't involved in the study.
"We know that any weight loss is likely to improve symptoms over the
longer term," Wluka said by email. "Weight loss with exercise is
important to maintain weight loss."
SOURCE: http://bit.ly/2ymt6UI Arthritis Care and Research, online
June 18, 2018.
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