The Multicenter Osteoarthritis (MOST) study, which is looking for modifiable risk factors for knee osteoarthritis, is enrolling at least 150 additional participants at UAB, age 45 or older.
Photo by Jennifer Alsabrook-Turner, UAB Marketing and CommunicationsA long-running national study of knee osteoarthritis — a condition that will affect nearly half of Americans as they age — has just begun recruiting additional participants.
Osteoarthritis occurs when the cartilage surrounding the ends of bones breaks down, allowing two bones to rub together. That friction causes pain, stiffness and swelling. Approximately 46 percent of people will develop knee osteoarthritis during their lifetimes.
The MOST, or Multicenter Osteoarthritis, study was launched in 2001 by the National Institute on Aging to improve understanding of a condition that is a major cause of disability in the United States. The study enrolled more than 3,000 people at UAB and the University of Iowa, ages 50–79. Its mission was to identify modifiable risk factors for knee osteoarthritis, to find groups who would benefit most from prevention efforts, and to determine whether the same factors that put a person at risk for knee osteoarthritis also make the disease worse after it has been diagnosed, or whether they differ. As of 2024, the study had recruited more than 4,500 participants.
To learn more about participating in the MOST study, call (205) 975-0988.
UAB has been a clinical center for the MOST study from the beginning; in 2023, the university received a $6.9 million grant to continue the study through 2028 and to enroll at least 150 additional participants at UAB.
When MOST began, traditional X-rays were the standard way to diagnose knee osteoarthritis, even though cartilage does not appear on an X-ray. “You are just inferring cartilage from where the bones are,” said Cora E. (Beth) Lewis, M.D., chair of the Department of Epidemiology in the UAB School of Public Health and principal investigator of the MOST clinical center at UAB. “And X-ray images didn’t necessarily match the patient’s symptoms.”
MOST has pioneered the use of several new diagnostic tools, Lewis says. The initial phase of the study was the first to use MRI in knee osteoarthritis. It demonstrated that bone marrow lesions and synovitis (inflammation of the fluid-filled sac in the knee joint) were powerful predictors of future knee pain. In the previous phase, MOST III, researchers started using CT scans to examine the buildup of calcium crystals in the knee joint. These crystals can be seen deposited in knee cartilage such as the meniscus cartilage and the membrane surrounding the knee joint called the joint capsule. “We found that the odds of knee pain were twice as high in participants who had calcium crystal deposits in their knee compared to participants who didn’t have these deposits,” Lewis said. This is important because it could mean that some people with knee osteoarthritis might particularly benefit from treatments targeting crystal deposits and inflammation.
In MOST IV, researchers will be pioneering the use of weight-bearing CT scans, Lewis says. With weight-bearing CT, participants stand upright and the scanner moves up and down to scan their legs in their natural position. “A large part of knee osteoarthritis is mechanical,” Lewis said. “We can look at the alignment of the leg to see if it is evenly balancing weight, and we can see if any structures change with weight-bearing, such as a meniscus cartilage bulging.”
Researchers also are going to compare participants who have only knee osteoarthritis, which may be due to joint-specific factors, with participants who have both knee and hand osteoarthritis, which may involve inflammation in the body overall, Lewis says. The researchers will use ultrasound to find fluid that can build up in the joint, Lewis says. In severe cases, this is obvious; but ultrasound will allow the researchers to find less severe cases. They plan to test synovial fluid in some participants using a sophisticated analysis tool that can differentiate 2,000 different types of proteins to see if they can detect any differences in protein patterns. They will also use that fluid to test for crystals and determine the specific crystal type.
Another area of investigation in MOST IV is the temporary pain relief, and reduced sensitivity to pain, that many people experience after they exercise. However, some people have no change or worse pain sensitivity with exercise, which may mean they will not respond to first-line exercise-based treatments for osteoarthritis. Participants will take part in an innovative test of movement, exercise and pain.
Participants must be age 45 or older, with no diagnosis of rheumatoid arthritis or any other inflammatory arthritis. They also must not have had knee replacement surgery.
Participation includes a comprehensive visit, which takes about four hours, with a follow-up visit after two years. Although the study does not provide treatment, participants do get a report including results from tests done as part of the study. They also receive a regular newsletter that includes summaries of research papers and other results from the study. “People enjoy the feedback we give them,” Lewis said. “They like to get that information on their knees, and many are interested in the science coming from the study.”
To learn more about participating in the MOST study, call 205-975-0988.