TUESDAY, July 14 (HealthDay News) -- If fear of heart disease and diabetes isn't enough reason to slim down, here's another: Being overweight or obese can cause rapid deterioration of the cartilage in the knee, leading to osteoarthritis, researchers report.
Osteoarthritis usually progresses slowly, but some patients experience a more rapid progression. This is the first study to connect obesity with fast progression of the disease and cartilage loss.
The report is published in the August issue of Radiology.
The researchers recruited 336 patients from a major osteoarthritis study. All were overweight and at risk of osteoarthritis, but had minimal or no loss of cartilage in their knees, said the researchers, who were led by Dr. Frank W. Roemer, an adjunct associate professor at Boston University and co-director of the quantitative imaging center in the department of radiology at Boston University School of Medicine.
During 30 months of follow-up, 20.2 percent of the patients showed a slow loss of knee cartilage and 5.8 percent had rapid cartilage loss, the study found.
The main risk factors for cartilage loss were pre-existing cartilage damage, being overweight or obese, tears or other injury to the cartilage at the knee joint (meniscus), and severe lesions seen on an MRI. Other factors include inflammation of the membrane lining the joints and abnormal build-up of fluid in the joint, according to the report.
Being overweight was associated with rapid cartilage loss, Roemer's team found. In fact, for every one-unit increase in body mass index, the chances of rapid cartilage loss increased 11 percent.
The association between obesity and rapid cartilage loss remained even after taking into account age, gender and ethnic background.
"It is a disease without treatment at present other than symptomatic -- mostly pain therapy and surgical total joint replacement," Roemer said.
"We know that weight loss is probably the most important factor to slow disease progression," Roemer said. "Additional studies will have to show if other measures, such as vitamins or targeted treatment of bone marrow lesions, will help to slow progression," he said.
Dr. Sean Scully, a professor of orthopedics at the University of Miami Miller School of Medicine in Florida, agreed that the danger of developing osteoarthritis is another reason to control weight.
"Don't let yourself get heavy," Scully said. "This study shows a direct correlation -- people who are heavy are the ones that are getting worse," he said.
Keeping your weight down -- through diet and exercise or weight-loss surgery -- could prevent the need for knee-replacement surgery, he said.
SOURCES: Frank W. Roemer, M.D., adjunct associate professor, Boston University, co-director, quantitative imaging center, department of radiology, Boston University School of Medicine; Sean Scully, M.D., Ph.D., professor of orthopedics, University of Miami Miller School of Medicine, Fla.; August 2009,Radiology