A new study commissioned by ESPN and funded by the National Institute on Drug Abuse suggests that retired NFL players are suffering a lot of pain: 7% are taking at least one prescription opioid painkiller, according to the study, a rate four times higher than that of the regular population.

Combine the findings with a Dec. 2010 report that showed that concussions are up 21% in the NFL this year, and a Sept. 2010 study finding that retired players are 19 times more likely to have dementia or Alzheimer’s than other men ages 30 to 49, and that’s a lot of bad news for pro football players. (More on Time.com: Study: Boys, Girls Suffer Different Concussion Symptoms)

The current study, conducted by researchers at Washington University, St. Louis, surveyed 644 former players who retired between 1979 and 2006 to track their use of prescription drugs, including Vicodin, codeine and oxycodone. about 52% of the players said they had used painkillers during their football careers, and 71% of those had misused the drugs (i.e., they didn’t take the drugs as prescribed or took drugs prescribed to someone else). in fact, 63% of the athletes who had used prescription painkillers during their playing days said they had gotten pills from coaches, teammates, trainers or from the Internet — not from medical professionals.

About 15% of players who had misused prescription drugs before retirement were still doing so after hanging up their jerseys. Players who misused drugs while playing were three times more likely than players who didn’t to continue misusing them after retirement, the study found. (More on Time.com: Down Syndrome Goes Viral, Thanks to a High School Touchdown)

Although the study didn’t indicate levels of drug dependence, it does suggest that ex-NFL players are in pain. “The rate of current, severe pain is staggering,” said lead investigator, Linda B. Cottler, a professor of epidemiology in Washington University’s psychiatry department, in a statement.

Still, the NFL’s medical adviser for substances of abuse, Dr. Lawrence S. Brown, told ESPN that the study was fundamentally problematic. “It is scientifically flawed to compare the general population with athletes, active or retired,” he said, adding that professional athletes are more vulnerable to injury and to prescription-drug misuse than the general population.

But the fact remains that players are suffering — they said so themselves. Only 13% of the players surveyed said they were currently in excellent health; 88% said they had been at the beginning of their careers. (More on Time.com: Could Painkiller Use in Pregnancy cause Problems in Baby Boys?)

The study is published online by Drug and Alcohol Dependence, and a full evaluation of the data is available on ESPN’s outside the Lines.