When it comes to easing the symptoms of knee osteoarthritis (OA), the more weight loss, the better, according to researchers at Wake Forest University in Winston-Salem, North Carolina. In a study published recently online in Arthritis Care & Research, Stephen Messier, PhD, and colleagues report that overweight and obese adults aged 55 and older with knee OA who lost 20 percent or more of their body weight saw far greater improvements in pain, function, quality of life, inflammation and knee joint stress than those who lost less.
In an earlier trial, the same researchers found that a weight loss of 10 percent – the amount the National Institutes of Health recommends for overweight and obese adults – improved mobility and decreased pain by 50 percent over an 18-month period. In their latest findings, they say doubling weight loss can cut pain and improve function by another 25 percent.
Diet Plus Exercise for Best Results
Patients in the earlier trial used one of three weight loss programs: diet alone, exercise alone or diet plus exercise. Diet plus exercise resulted in the greatest average weight loss, followed by diet alone; on average, participants in the exercise alone group barely lost any weight. The diet was based on an intake of approximately 1,100 calories a day for women and 1,200 for men. At the start of the study, calories initially came from two meal replacement shakes and one plant-based, 500- to 750-calorie meal. Exercise was 15 minutes of aerobic walking (fast enough to get the heart rate up), 20 minutes of strength training and another 15 minutes of aerobic exercise followed by a cool down. Participants worked out for an hour at least three times a week. They also received nutrition education and cognitive behavioral therapy as well as weekly or biweekly weigh-ins.
For the current study, the researchers analyzed data from a subgroup of 240 of the earlier trial’s 399 participant – those who were in the diet plus exercise group and those in the diet alone group. In this analysis, patients were grouped into four categories based on how much weight they had lost: less than 5 percent (which wasn’t considered significant), between 5 and 9.9 percent, between 10 and 19.9 percent or more than 20 percent. (For a 200-pound person, for example, a 5 percent weight loss equals 10 pounds, a 10 percent loss equals 20 pounds and a 20 percent loss equals 40 pounds.)
Twice as Nice
By all measures, including pain reduction, the people who dropped more than 10 percent of their body weight fared better than those who lost less. But the greatest improvements were in the group that lost 20 percent or more. At 18 months, for example, those participants could walk 10 percent farther in 6 minutes than those who lost less than 5 percent (559 meters vs 508 meters).
“The importance of our study is that a weight loss of 20 percent or greater – double the previous standard – results in better clinical outcomes and is achievable without [drugs or surgery],” Messier says.
He acknowledges that dropping any amount of weight – and keeping it off – is tough. The researchers didn’t follow up with study participants to see if they maintained their weight loss.
Support is Key to Success
Messier also notes that, based on his experience and past studies, people who are successful at losing weight tend to have some things in common: They’re more likely to consistently use food logs, like MyFitnessPal; to exercise regularly, including adding extra workouts; to use meal replacements without becoming reliant on them; and to have strong family support. And those who struggle to lose weight are more likely to have lower incomes, work demanding jobs, live far from a gym or other place to work out, be primary caregivers and have multiple health problems.
These people need more support and help from health care providers, say experts such as Henning Bliddal, MD, a research professor at Copenhagen University Hospital in Denmark and chairman of the Danish National Board of Health’s commission for the treatment of knee osteoarthritis.
In 2014, Dr. Bliddal and colleagues published a study highlighting the importance of both exercise and at least a 10 percent weight loss as primary treatments for OA, while also noting that sustained weight loss can be challenging for many people.
In response to the recent analysis, he writes that Messier and colleagues “demonstrate convincingly that the larger the weight loss, the better for all relevant outcomes, including pain and function. [Yet] weight loss above 10 percent is difficult without the use of meal replacements, which over the years have been a central part of the regimen in several successful weight loss trials for patients with knee OA.”
He points out that this is different from most diets, in which people lose only about 5 percent of body weight.
“The difficult part of the job then is to taper this intervention [meal replacements] and replace it with a maintenance regimen without losing momentum,” he notes. “The focus must be to obtain and maintain as many high losers – more than 10 percent – as possible. Such a strategy has the potential to alter the clinical course of OA.”
Dr. Bliddal says it remains to be seen whether these greater weight loss benefits would also stop the structural damage from OA, which would prevent or delay end-stage disease and reduce the need for knee replacements.
Author: Linda Rath
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