Correlation Does Not Imply Causation

You never know how strong you are until being strong is the only choice you have.

Bob Marley
circa 2004

When times are uncertain we want desperately to find a way to convince ourselves that we have things figured out. We are in control. This is why, in the Covid 19 era,  there has been an absolute fire hose of people pointing to loosely grounded cause and effect anecdotes about the disease in the hopes of confirming their own biases.  We have all heard things like “States with Democrat governors have the highest mortality rates” or “Countries run by women have the least numbers of infections”.  While it may be comforting to our egos to latch onto these tidbits as they come along, it actually serves no purpose in gaining understanding about the spread of the virus. As it turns out, we know very little about most things. 

I’m going to take this back to ALS, because this is a blog from a guy and his wife with the whole tweed jacket and ALS backdrop. One thing that seems to surface again and again is a  commonality in the diagnosis story as told by patients.  It starts out with a back story about a love for sports and fitness since childhood. Then “I was in the best shape of my life when I started to notice (insert sign of early motor dysfunction)”.  I and many others have been drawn to conclude that extreme fitness causes ALS.  It’s perfect because it seems to be repeatable, there are plenty of high profile athletes with ALS to give anecdotal support, and it gives a little boost to the ego to be cataloged with the likes of Lou Gehrig and Catfish Hunter (both insanely good athletes).  The problem is that, while there is undoubtedly a correlation between being shredded and getting ALS, it is not scientific to suggest being jacked causes ALS. 

circa 2008

There are a ton of scientific explanations for why we shouldn’t jump to conclusions, but the simplest one is the lack of evidence from counterfactual states.  Remember that all squares are rectangles but not all rectangles are squares?  Well we are more like parallelograms in this example. The overwhelming majority of extremely fit people do not get ALS. Furthermore, some couch potatoes DO get ALS. So while it is accurate to say that a lot of the people who get ALS were fit, you can’t say that all of them were. Nor can you say that all fit people get ALS. Thank God. 

ALS survivor, Sarah Nauser-Olsen

Another problem is that we don’t know when and how ALS starts to affect the whole person. At face value it seems logical to suggest the fitness came before the disease. But recent research suggests changes at the cellular level occur years before noticeable symptoms. This means we have to allow for the possibility that something in the pathology of the disease makes a person more inclined to be an absolute beast. So even if we do definitively link athletic domination to ALS,  we are still left with the question of what came first. The chicken or the egg? Aside from chiseled abs and godlike speed, there are a lot of other factors to consider if you manage to make a clear correlation between extreme fitness and ALS. Are there other factors common to athletes that can also be considered as ALS risk factors to non athletes?  Some of the hypotheses I have heard range from head trauma and exposure to pesticides to something as simple as a high protein diet. And that really gets to the heart of the issue. The possibilities are not limitless, but there are certainly more than any individual could analyze without help. 

Fitness industry and ALS community leader Augie Nieto

I do think we have an important clue that can lead us to more clues which in turn lead to more.  That is how the people with the big brains paint a complete picture. And that is actually why I wrote this blog today. While it might be comforting for  us to simply draw our conclusions, there are smart people doing the hard work of questioning every conclusion, and they are doing it on our behalf. At The ALS Therapy Development Institute,  The Precision Medicine Program (PMP) is the most comprehensive and longest running translational research study in ALS.They are looking at these questions and so many more to try to piece together this puzzle.  Unfortunately like most non profit organizations they are having a difficult time keeping up with operating costs.  Augies Quest has been tireless in keeping the lab open in Cambridge and keeping patients connected to the research. 
If you are fortunate enough to be in the position to give during this period of uncertainty, and you want to help unravel this mystery to save lives, I can think of no better place than Augie’s Quest.

Augie's Quest | ALS Therapy Development Institute

One thought on “Correlation Does Not Imply Causation

  1. I think that ekstreme fitness and use supplement with genetic factor risk of ALS.When l asker my ALS patients did you do sport
    Some of them said me YES so my opinium athletes higher risk of ALS more than normal people

    Like

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