Although the results of a two-year study at the U seem to show that two nutritional supplements don’t have an effect on slowing cartilage loss, U researchers believe a longer study could show more positive results.
Daniel Clegg, a professor of internal medicine, led the U’s study with another research center to see whether either of the two supplements naturally used by the body to build cartilage could help slow the effects of osteoarthritis, a joint disease that breaks down cartilage over a long period of time.
Allen Sawitzke, a professor in rheumatology, said they took about 582 volunteers with moderate onset of osteoarthritis and separated them into five different groups. Each group took three pills of one of the drugs: a combination of the two, another drug currently used for osteoarthritis or a placebo pill.
The knee cartilage in each participant was measured by an X-ray over time.
Sawitzke said both of the supplements slowed cartilage loss more than the placebo, but the statistical difference was such a small amount that the difference didn’t seem enough for the supplements to be considered effective.
Over two years, people who took one of the tested supplements showed about .10 millimeter less cartilage loss than the placebo pill. There is three to four millimeters of cartilage in the average human’s knee.
“Osteoarthritis is something we develop over many years,” Sawitzke said. “If there is this much change in two years, think about how much it could be in 10 years.”
The difference between the placebo and one of the supplements is .15 millimeters, but at the same rate over a 10-year period, the difference might be .608212; more than one-eighth of the cartilage in the knee. Researchers completed a 24-week study to test whether either supplement relieved the amount of pain more than the placebo did. The study was published almost two years ago, but researchers continued the study.
European researchers completed a similar study a few years back that led scientists to believe that both of the supplements had an effect on cartilage loss.
Sawitzke said the U’s combined study was similar to the European study. He said there was a slight difference in the dose amount, the X-ray mechanism and the way the supplement was prepared as a pill, but there were no big differences.
Clegg said the study does show researchers better techniques to monitor and measure the progression of osteoarthritis.
Sawitzke warns that although the results seem null, it really means they can’t show it works yet.
“We’re pleading to the idea that there needs to be another study,” he said. “Perhaps with more people and more time.”
Researchers are still analyzing the rest of the data for another year, but Sawitzke said there are no plans to start a longer study.