Scientists have found that, for every additional tenth of a part per million of selenium in volunteers' bodies, there was a 15 percent to 20 percent decrease in their risk of knee osteoarthritis.

Those who had less mineral than normal in their systems faced a higher risk of the degenerative condition, in one or both knees. The severity of their arthritis was related to how low their selenium levels were.

University of North Carolina and Chapel Hill Thurston Arthritis Center medical scientists and colleagues conducted the research which focused on the knees of 940 participants enrolled in the Johnston County Osteoarthritis Project.

"We are very excited about these findings because no one had ever measured body selenium in this way in relationship to osteoarthritis", said study leader Dr. Joanne Jordan of UNC.

"Our results suggest that we might be able to prevent or delay osteoarthritis of the knees and possibly other joints in some people if they are not getting enough selenium. That's important because the condition, which makes walking painful, is the leading cause of activity limitation among adults in developed countries."

Fish, meat, poultry, whole grains and dairy products are good sources of this mineral nutrient in the human diet.