IRA FLATOW, HOST:
This is SCIENCE FRIDAY, I'm Ira Flatow. Football season is getting into full swing this week: tailgating parties, point spreads, Tim Tebow. But amid all the excitement of a new season comes an old and disturbing ghost. This week, a new study finds that pro football players may be more likely to die from various neurodegenerative diseases, such as Alzheimer's or ALS, more likely than the rest of us.
Everett Lehman is one of the authors of the paper published this week in the journal Neurology. He's with the National Institute for Occupational Safety and Health, part of the Centers for Disease Control and Prevention in Cincinnati. Welcome to SCIENCE FRIDAY.
EVERETT LEHMAN: Oh, hello, Ira, it's good to be with you today.
FLATOW: You're welcome, thank you. So you were looking at the health of people who played professional football from 1959 to 1988, correct?
LEHMAN: That's correct.
FLATOW: And what did you find?
LEHMAN: We found that this group of players, that although overall they were much healthier than the general population in the area of neurodegenerative diseases such as ALS, Parkinson's and Alzheimer's, they were three times more likely to die from those diseases than those of the general U.S. population.
FLATOW: Now there can't have been many people who played pro football during those years and have died already. So this is a pretty small sample.
LEHMAN: Right, right, that's a good point. That is a limitation of the study. There's only, of the 3,439 players, we only have 334 deaths, which is only in 10 percent of that group. So it is based on small numbers at this point.
FLATOW: But the numbers are high enough that you feel compelled to talk about them.
LEHMAN: Right, that's correct. They are small numbers, but from a statistical standpoint, they are significant results, and we feel that it is valid to present these as something serious.
FLATOW: And Alzheimer's and Lou Gehrig's disease, those are the two standouts. Are there others?
LEHMAN: The three that we looked at were ALS, Parkinson's and Alzheimer's, and ALS and Alzheimer's were the highest, though we did note in the paper that it's really important to look at the overall category of neurodegenerative diseases because there is some overlap and some common ideology among these diseases, and it may be a common promoter among all of them.
FLATOW: 1-800-989-8255, talking with Everett Lehman of NIOSH. Can you make any kind of cause and effect claim here?
LEHMAN: We're very cautious about doing that. The main reason is that we did not have good data on concussions for this group, and of course concussions is the issue that's on the table as causing neurodegenerative diseases, and players who participate in contact sports, especially football. So we were cautious not to draw that connection.
However, there is quite a body of recent research that has very clearly come out in support of the connection between concussion and neurodegenerative diseases.
FLATOW: And so you were able to collect the data from where?
LEHMAN: Yeah, you know, it's interesting. We've had data on this group of football players for more than 20 years, dating back to around 1990. We have obtained a database of retired professional players, those of us in the NFL Retirement Fund, those players who played more than five years. So the NFL and the Players' Association provided us that information back in the early '90s.
We completed a report on the cardiovascular disease outcomes of this group of players, and we followed them to the present. We just completed a follow-up cardiovascular disease study about nine months ago and just recently completed study of neurodegenerative diseases.
FLATOW: So while you have the data, the medical records, you said - you were looking for heart disease, you said hey, let's see if there's anything having to do with these others.
LEHMAN: Right, yeah, we looked at death certificates. We didn't have medical records per se, but we looked at the causes of death on death certificates. And cardiovascular disease has been of interest for a number of years because of the size of these guys, you know, and the link between obesity and cardiovascular disease.
But as we continue to follow that aspect, we also were aware of the developing literature on neurologic problems among football players, and this was a great opportunity to examine that.
FLATOW: Did it matter what position you played?
LEHMAN: It appears to. We did an analysis where we split up this group and took a look at the results from each. We looked at players, linemen who, you know, played the line position, the professional line positions, and compared those to the non-linemen. And the non-linemen are the ones we designated as the speed players, and we called the linemen non-speed players, and we did a comparison between the two.
Now this stratification is based on some other recent research which has shown that depending on the position you play, you may be at higher risk of concussion. So we looked at it the same way and said are positions at increased risk, you know, of neurodegenerative death? And we did find that the non-linemen had three times the risk of neurodegenerative death than the linemen.
FLATOW: So the guys who were running really fast when they get hit.
LEHMAN: Yeah, exactly, that - you know, some people think maybe the linemen were at an increased risk because they're banging heads all the time, but that doesn't appear to be the case either in concussion or in our study because, just like you say, the linebacker running down a running back or a cornerback after a wide receiver are able to build up considerable momentum prior to that hit. So that collision is much more serious than what the linemen experience.
FLATOW: What was your reaction when you went back, when the study has been published now? Any reaction from the NFL or from the Players' Association?
LEHMAN: We haven't heard from either. You know, we do maintain some contact with both. So when we do our reports, we do send them to both the NFL and the Players' Association for comment. We didn't receive any on this paper.
But we also will send out a fact sheet to the players that are still living in this cohort, with a fact sheet explaining the results of the study and steps that they may want to take to protect their health.
FLATOW: Was there a change in life expectancy or the age that these players died?
LEHMAN: The one analysis that we do looks at the overall mortality of this group, and by and large, football players have a much better life expectancy than the general population, but that's not really unexpected. These are supermen, really. I mean, they have superior physical conditioning, they have probably exceptional diets, don't smoke as much and have really good medical treatment. So from that standpoint, it's better overall.
There is a little bit of concern about cardiovascular disease and neurodegenerative diseases.
FLATOW: Now, these players that you looked at played through 1988, but there have been changes in how the league deals with concussions and attempts to take protective measures since then.
LEHMAN: Yeah, yeah, yeah, for sure, especially within the last number of years as this additional research is coming out. The NFL has made several rules changes because of concerns about concussion. A couple of those involve kickoffs, where they have moved the kickoffs up five years and have eliminated the blocking wedge to protect, you know, ball returners, primarily, and also blockers because of the speed these players develop in covering kickoffs.
And they've also strengthened the penalties for blocks and tackles involving the head and neck. And one other non-rules change that I know the NFL has implemented is the medical management and treatment of players who receive concussions. It's been disseminated among all the NFL teams and enforced pretty stringently.
FLATOW: Is there any way to go back to college-level football?
LEHMAN: Well, that's a likely area of additional study, and there are - have - there have been several studies done involving college players, and several have looked in-depth at certain teams. Certain researchers have followed specific teams throughout an entire season and have been able to monitor concussion activity among the players and their medical outcomes over a season.
And that's really very useful information. I think that's also been done for a high school team. And that is the type of research that will really inform the future on concussions and long-term neurologic problems.
FLATOW: Let me see if I can get a quick call in from Alan(ph) in Lake Orion, Michigan. Hi, Alan.
Hi. Because of my sports collection, I have a fantastic sports collection, I was allowed to put on shows by the Detroit Lions of the 1952, '53 and '57 world championship teams 50 years later, OK? And four of the men that I met, four of the players, died of dementia, and one was a wide receiver, one was a strong safety, one was a defensive lineman, and the other one was a running back.
The strong safety played with a leather helmet until around 1955, when he switched over. Leather helmets were simply - there was no protection. I talked to him about it, and they used to spray-paint the leather helmet. But the interesting thing was helmets back in those days, like when I was a child, they were just hard plastic. And I'm sure they are the cause of dementia.
And one of the players, his name was - well, maybe I shouldn't mention it. There's been a study done about him. He actually did not have concussions. He had 17 concussive blows, they figured out, in his brain. OK? So I'll get off the air and let you guys talk.
FLATOW: OK, Alan, thanks a lot. You couldn't get - you didn't go far back enough in time for those leather helmets, right?
LEHMAN: Well, no, but, you know, the caller does raise a couple of interesting points, and the issue on helmets is really controversial. There is actually a body of thought that the improvement in the helmets, though improving traumatic injury to the head, may lead players to lead with their head more or use their head more in blocking and tackling.
You know, where it protects the head, you don't feel it as much. There may be problems with players feeling somewhat invulnerable and using their helmet. So the fact that the helmets weren't much early on, that they may have just been leather versus the new helmets, that's really, really an interesting issue.
And the other issue the caller brought up was concussive hits to the head. I've been generally using the term concussions because that's the term used in most literature. But there's also a thought that these sub-concussive blows to the head may also, you know, be at issue, where it may not necessarily be a concussion but just cumulative hits to the head may add up over time and cause problems.
FLATOW: Dr. Lehman, thank you very much for your time, and good luck to you. I'm sure we'll be following your research.
LEHMAN: OK, bye.
FLATOW: Everett Lehman of NIOSH in Cincinnati, Ohio. We're going to take a break. When we come back, we're going to talk about West Nile virus. It's been almost everywhere. We'll talk about other viruses and mysterious ones, and they're showing up. Stay with us. We'll be right back after this break.
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FLATOW: I'm Ira Flatow. This is SCIENCE FRIDAY from NPR News. Transcript provided by NPR, Copyright National Public Radio.