CHICAGO -- Government research on more than 3,000 retired NFL players concluded suicides were less common among men in this group than in the general population.
The research did not resolve the issue of whether suicides are more common in players with a degenerative brain disease -- chronic traumatic encephalopathy -- linked with repeated concussions. The study did not examine concussion data or whether any of the players involved had CTE.
The research is from the National Institute for Occupational Safety and Health, part of the federal Centers for Disease Control and Prevention. The agency has for decades been studying a group of retirees who played at least five seasons between 1959 and 1988.
Previous results from the ongoing research found the players had longer lifespans than men in the general population and were less likely to die prematurely from cancer, violence and accidents. But it also found they faced higher chances of dying from Alzheimer's disease and other brain disorders.
The suicide report involved 3,439 former players and found 12 suicides during the study years from 1979 to 2013. Suicide rates in the general population suggest 25 suicides would have been expected for men of comparable age. The results will appear in the September print edition of the American Journal of Sports Medicine. They appeared in the online edition last week.
"The issue of football players being at higher risk of suicide than the general population has been raised in the popular and scientific literature," Dr. Douglas Trout, deputy director of the Division of Surveillance, Hazard and Field Studies at the CDC's National Institute for Occupational Safety and Health, said in a media release.
Suicides in several former NFL stars including Junior Seau, Dave Duerson and Ray Easterling -- all diagnosed with CTE -- have raised concerns about risks facing other players. CTE can only be diagnosed after death and has been found in dozens of former players.
"Clearly, our one study does not resolve the issue of suicide in football," the study concludes. "Before reliable conclusions can be drawn on any relationship among football play, concussion, CTE, and suicide, more work needs to be done in several areas."
The Associated Press contributed to this report.