Insufficient levels of selenium in the body may be associated with a higher frequency of knee osteoarthritis, according to new research. Past studies have indicated that, in a particular area of China, severe shortages of selenium in the body may lead to early-onset osteoarthritis. Selenium is incorporated into proteins that regulate thyroid function and may impact the immune system.

Researchers conducted an evaluation of selenium on a Western population sample to determine if a risk factor existed that could actually help to avoid or control knee osteoarthritis, the leading cause of activity limitation in adults in developed countries. Each of the 940 individuals in the sample submitted toenail clippings for selenium assessment. Toenails, which grow slowly, provide a reflective and consistent estimate of selenium in the body over a long period of time, and can be used to calculate the selenium in the body over months to a year.

The results demonstrated that low toenail selenium levels were associated with increased odds of radiographic knee osteoarthritis. Although these associations occurred in both races and sexes, some effects were more notable in African Americans and women.

“This shows that low selenium levels may be a potential and, more importantly, modifiable risk factor in osteoarthritis,” said Joanne M. Jordan, MD, MPH, of the University of North Carolina. “These data are preliminary but it certainly clears the way for future studies to confirm these results and to examine whether selenium supplements, taken in the right quantities, can reduce the development and progression of osteoarthritis.”

American College of Rheumatology (ACR), Nov 8, 2005