What to do about heading?

Heading the ball — photo courtesy of Wikimedia

I have been meaning to write a blog post for over a week, since a bit of breaking sports medicine news occurred with the publication of some research in the New England Journal of Medicine (NEJM).

It took a Tweet this morning to rouse me to action.  I promise it hasn’t been sloth on my part that has slowed my hand, but pleading “I’m busy” to the group of folks who usually will be reading CJSM media is not going to gain much sympathy.

And yes, with fall sports, I sure have been busy.  But I am sure you have too.

I hope, however, not too busy to have missed this piece of research from NEJM: “Neurodegenerative Disease Mortality Among Former Professional Soccer Players.”  There was an accompanying editorial to this study, a piece that is most definitely worth a read too. “Soccer and Mortality — Good News and Bad News”

The published research was a large retrospective cohort study looking at former professional Scottish football (soccer) players: 7676 cases were identified from databases of Scottish football players and 23,028 controls (3:1) from the ‘general population’ were identified using a Scottish ‘Community Health Index.’ Controls were matched to players on the basis of sex, age, and degree of social deprivation.  Of note, all the participants in this study were male.The researchers looked at two dependent outcome variables:  i) cause of death as noted on death certificates and ii) dispensed medications, information for which was obtained from the Scottish national Prescribing Information System.  Follow up information for study participants was for a median of 18 years (for each individual, “Age was used as the time covariate, with follow-up from age 40 years to the date of data censoring, which was either the date of death or the end of the follow up (December 31, 2016), whichever occurred first).”

The researchers report several important findings in this study, to note just a few:

1. Mortality from neurodegenerative diseases was higher and dementia-related prescriptions were more frequent in the cohort of former football players than in the general population.
2. The risk of dying from neurodegenerative disease was almost 3.5 times higher for footballers (HR 3.45; 95% CI, 2.11 – 5.62, p < 0.001). Put another way, 1.7% of former footballers in this study died from these conditions (compared to 0.5% of controls).  Put yet another way 1:59 former footballers died of neurodegenerative diseases compared with 1:200 of the general population.
3. Conversely, former football players were less likely to die from other causes.  All-cause mortality was lower among former players than among the general population up to 70 years of age (HR 0.80; 95% CI, 0.66 – 0.97, p < 0.02).  Regarding specific diseases such as ischemic heart disease and lung cancer, there too former football players were less likely to die from these conditions than those in the general population.

I would recommend the original study (which is freely available) to you to read for yourself.

There are many ways to interpret these findings.  I do think the accompanying editorial provides a very good framework for understanding this important new study.  The writer notes the importance of the findings, and gives an overall interpretation that elite football appears to raise the risk of neurogenerative disease but is protective for avoiding death from common nonneruologic causes.  The writer further makes the obvious but noteworthy cautions and recommendations

1. This is a cohort study, with all the known limitations attendant.  Correlation has been shown but not causation
2. A significant limitation is the exclusion of women and the need for including former female professional players in future studies.
3. Amateur players, both male and female, must now be studied.
4. “…prospective longitudinal investigations to examine possible relationships between heading and neurodegenerative disease….” are needed

The CJSM EIC Chris Hughes and I have discussed this important study, and we would add two additional cautions:

1) Reliance on accuracy of diagnosis recorded on death certificates is notoriously unreliable, especially with some conditions including neurodegenerative conditions – these data may both over-and under-report diagnosis on death certificates.

2) The inferences made regarding ‘dementia associated medications’ must be noted.  With the data as reported, it appears impossible to note the specific indication for the medications used, and said medications may well have been prescribed for other indications as well, both appropriately and inappropriately.

The most important point the editorialist made, I think, is this: “These new findings by Mackay and colleagues should not engender undue fear and panic among soccer players, parents and coaches. As the authors of the current study indicated, it is not possible to generalize their findings among male former professional soccer players to participants in recreational, amateur, or collegiate level soccer.”

And so, sure enough, what were the headlines in the media accompanying the release of this study?  The Sun led with this:

“BRAIN INJURY FEARS: Ex-pro footballers 3 time more likely to get dementia from heading balls, new research finds”

If it bleeds it leads. Sigh.

BTW I will NOT link to that article itself, but to a more responsible NHS commentary that contextualizes and rebuts it, should you want to learn a bit more about the media buzz surrounding this study.

As I wrap up this post, I would like to leave you with a few thoughts and return to where I started.  What was it that roused me as I scrolled through my Twitter feed this morning?  The Tweet that got my notice was linked to this BBC piece: “Scottish Youth Football Association (SYFA) Urges Members to Ban Heading for Under-11s” Citing the new study specifically, despite the authors’ own cautions against generalizing the results to young amateur footballers, the SYFA is urging a ban on heading in youth football.

This is translational research happening live — in my experience it is rather rare that scientific research in some hoary journal gets turned into real-life policy at this speed.This is an important conversation, and though the science is unsettled, decisions are being made. What do you think of all of this?  It would be great to hear from you in the comments below or on Twitter @cjsmonline

And as for our busy busy lives?  You know, the one I blame for my slowness in sharing this now 10 day old study? Let me make a plug for my dear professional colleague Twitter.  I have heard many of my sports medicine colleagues say they are too busy for Twitter.  I would categorically state that having a dedicated Twitter feed where I follow thought leaders like @cjsmonline, and where I spend no more than five minutes of my day, is far and away the most efficient resource I have for staying up to date and what is breaking in the world of sports medicine. Consider Twitter if you don’t use it already.