Study: Protein Predicts Osteoarthritis Risk in Blacks

University of North Carolina researchers report it may be possible to predict whether blacks have a strong risk of developing osteoarthritis just by measuring the level of a protein in their bodies.

The researchers found for the first time that levels of cartilage oligometic matrix protein (COMP) are higher in the cartilage, ligaments, tendons and joint lubricating fluid of blacks with osteoarthritis than those without the disease. The same has been known of whites for a decade.

The researchers also found that average levels of the protein are higher in blacks, those with and without osteoarthritis, than in whites. A report on the findings appears in the March issue of Arthritis & Rheumatism.

Study author Dr. Joanne Jordan said just knowing how much of the protein is naturally present in the different races and sexes could become a major tool for determining when the illness occurs and when it advances.

"We must take these differences into account," said Jordan, associate professor of medicine at the UNC School of Medicine. "An African-American person, for example, could be falsely considered at high risk because of elevated COMP when in fact COMP levels are just higher in blacks normally."

More than 750 men and women of both races participated in the study, which involved measuring COMP levels in volunteers with no X-ray evidence of osteoarthritis. Jordan and her colleagues had already discovered that COMP increases markedly in the blood of people with hip or knee osteoarthritis before X-rays reveal joint damage.

In their new study, the researchers also found that COMP levels correspond closely with pain that patients with undiagnosed osteoarthritis report to doctors. People with five or more years of hip or knee pain, for example, showed about 33 percent more of the protein in their blood than people reporting no pain, she said.

"The best things people can do to minimize knee and hip osteoarthritis are to avoid activities that put heavy physical demands on joints and especially to lose any excess weight," Jordan said. "Also, evidence suggests it's important to keep thigh and other leg muscles strong through non-stressful exercise."

Other sources: University of North Carolina, Arthritis & Rheumatism (Vol 48, Issue 3, 675-681)