The Corpus Callosum

I
wrote about a similar topic a bit ago, it which a relationship was
found between href="http://scienceblogs.com/corpuscallosum/2007/04/depression_and_pain_in_retired.php">chronic
pain and depression in retired pro football players.
 Now, there is an NTY article that reviews some findings about
a relationship between concussions and depression.

title="NYT permanent link via RSS"
href="http://www.nytimes.com/2007/05/31/sports/football/31concussions.html?ex=1338264000&en=aa42809a8c7be226&ei=5090&partner=rssuserland&emc=rss">Concussions
Tied to Depression in Ex-N.F.L. Players

By ALAN SCHWARZ
Published: May 31, 2007

The rate of diagnosed clinical depression among retired
National Football League players is strongly correlated with the number
of concussions they sustained, according to a study to be published
today…

The
study was conducted by the University of North Carolina’s
Center for the Study of Retired Athletes and based on a general health
survey of 2,552 retired N.F.L. players. It corroborates other findings
regarding brain trauma and later-life depression in other subsets of
the general population, but runs counter to longtime assertions by the
N.F.L. that concussions in football have no long-term effects.

The study, which will appear in the journal of the American College of
Sports Medicine, found that of the 595 players who recalled sustaining
three or more concussions on the football field, 20.2 percent said they
had been found to have depression. That is three times the rate of
players who have not sustained concussions…


What is interesting about this article?  In a way, nothing.
 That is, the outcome of the study is pretty much what you
would expect.  When you bash the brain around, bad things
happen.

What caught my attention about the article was the way it was written.
 First, the author presents the findings.  He notes
that the findings are consistent with other research, but that they
contradict what the NFL says:

It
corroborates other findings regarding brain trauma and later-life
depression in other subsets of the general population, but runs counter
to longtime assertions by the N.F.L. that concussions in football have
no long-term effects…


The NFL even cranked up their spin machine:

One
committee member, Dr. Henry Feuer of the Indiana University Medical
Center and a medical consultant for the Indianapolis Colts, went so far
as to call the center’s findings “virtually
worthless.”

Regarding the issue of players’ recollection of brain trauma,
Dr. Casson said: “They had no objective evaluations to
determine whether or not what the people told them in the surveys was
correct or not…


So far, this is standard operating procedure for a reporter.
 You report what one side says, then give the other side a
chance to respond.  That tends to be the format, regardless of
how lopsided the evidence is.  Even if what one side has to
say is completely kooky, they get equal time.  It leaves the
uninformed reader with the impression that there is a true dispute or
controversy.  

But Mr. Schwarz did not let this one go.  He followed up:

After
reading the depression study and considering the league’s
issues with recollective survey research, Dr. John Whyte, the director
of the Moss Rehabilitation Research Institute in Philadelphia and an
expert in neurological research methodology, said he did not share the
league’s criticisms.

“To the person who says this is worthless, let’s
just discard a third of the medical literature that we trust and go by
today,” said Dr. Whyte, who has no connection with either the
N.F.L. or the Center for the Study of Retired Athletes, which is partly
funded by the N.F.L. players union. “Here, the response rate
was good and not a relevant issue to the findings. We have some pretty
solid data that multiple concussions caused cumulative brain damage and
increased risk of depression, and that is not in conflict with the
growing literature.

“Do I think this one study proves the point beyond doubt? No.
Does it contribute in a meaningful way? You bet.”


Good.  Then, Schwarz goes on to describe some of the high
points of the study methodology:

…Respondents
were on average 54 years old and had played almost seven seasons in the
N.F.L. A minimum of two seasons was required for inclusion in the study…


Of course, retrospective studies are not the best, but sometimes it is
all you have.  Done well, they can provide valid information.
 Considering that it would not be ethical to do a prospective,
randomized, controlled trial, you have to start somewhere.

The NFL plans to do its own study.  No word on how they plan
to conduct it.  Ideally, it would be a prospective study that
would either involve every single player, or would include a sizable,
random, representative sample.  

Technicalities aside, I was glad to see the reporter make an effort to
present a complete view of the story, not merely a balanced view.

 

Comments

  1. #1 Toby J
    June 1, 2007

    When I heard a snippet of this news item on the radio today, my first thought was “correlation is not causation,” and that perhaps retired football players have many other reasons to be depressed. Like realizing they wasted their life playing football.

  2. #2 stumpy
    June 1, 2007

    I agree that this represents good reporting. If only the NYT and other prestigious/influential papers had done a more thorough job in the 2000 presidential elections, for example, or in the run-up to the Iraq imbroglio. Maybe things would’ve turned out differently.

  3. #3 Dr. Deb
    June 1, 2007

    Makes sense to me.

  4. #4 daedalus2u
    June 2, 2007

    Makes perfect sense to me. There is good correlation between vascular damage and depression, in older people, vascular depression is well known. Hemoglobin in CSF destroys NO and is (what I think) can lead to vasospasm during recovery, until is is all cleared out and the damage repaired (which is why nitrite prevents that).

    http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=15784871

    Of course smaller bleeds will have smaller effect (but likely not zero). I think the long term impairment of brain perfusion observed in depression, Alzheimer’s, and the like following brain trauma is akin to the “vascular remodeling” that occurs in pulmonary hypertension, or congestive heart failure, or systemic sclerosis (or other things). It has to do with a disruption of the regulatory pathways that regulate capillary density and perfusion. If the capillaries are too far apart, the cells “too far” from a capillary are going to not do well, and may even produce chronic pain and inflammation.

    It is not a surprise to me that these things all correlate. I suspect they are all caused by essentially the same thing, low basal nitric oxide.