'For people losing 10 pounds, each knee would be subjected to 48,000 pounds less in compressive load per mile walked.... A reduction of this magnitude would appear to be clinically relevant.'

The findings suggest weight loss could help slow the progression of knee osteoarthritis.

The 18-month study included 142 overweight and obese adults over 60 years of age, all of whom were diagnosed with knee osteoarthritis and placed on weight-loss programs.

By the end of the study, participants had lost an average of two percent of their body weight and lowered their body mass index (BMI) by 3 percent.

Reporting in the July issue of Arthritis & Rheumatism, researchers at Wake Forest University, in Durham, NC, found that for every pound of weight lost, there was a four-pound reduction in the load on the knee for each step.

Hefty Reduction in Knee Load

"The accumulated reduction in knee load for a one-pound loss in weight would be more than 4,800 pounds per mile walked," lead researcher Stephen Messier said in a prepared statement.

"For people losing 10 pounds, each knee would be subjected to 48,000 pounds less in compressive load per mile walked. Although there are no longitudinal studies indicating that weight loss in humans slows the progression of knee osteoarthritis, a reduction of this magnitude would appear to be clinically relevant," Messier said.

He and his colleagues said their findings highlight the need for more research into the potential of weight loss to slow, or even prevent, knee osteoarthritis.

More information: The American Medical Association has more about knee osteoarthritis.