Cause?…Or Coincidence?


Those who shop and purchase small-sized clothing, live longer.  Not those that shop – which with its modest exercise would seem to be responsible for any existing health benefit – but those who actually buy smaller clothing.  At first, this doesn’t necessarily make sense.  Why would purchasing anything other than perhaps a bullet proof jacket, protective head gear or a basket of vegetables affect how long you live?

Here’s more – As a group, men with chronically high PSA levels (Prostate Specific Antigen, a marker for prostate cancer), more often require reading glasses than the group of men with normal PSA levels. Huh?  Is prostate cancer somehow responsible for poor vision? Not quite.

Similarly strange associations occur outside of healthcare.  One frequently discussed is that children who grow up with more books in the home, tend to have better educational test scores. At first, this seems to make some sense. But we’re not talking about kids who read or are read to more often – incidentally, there doesn’t seem to be much benefit in test scores from those activities – we are simply talking about living in a home with a lot of books.  It appears your teachers were wrong – you can get smarter simply from osmosis. Well…not exactly.

See, it’s not the act of purchasing small clothes that makes you live longer, it’s that those who purchase smaller sized clothing are typically smaller and those who are smaller tend to live longer.  Similarly, men with higher PSAs tend to be older. Older people, as I’m unfortunately becoming more familiar with, require reading glasses more often. (As for books and testing, parents who purchase books, tend to be smarter, more educated and promote education to their children.  These factors, not living near a stack of books, is what leads to higher test scores).

This highlights an important point that is not always obvious –  Just because two things are associated with one another, it doesn’t necessarily mean that one causes the other.

I bring this up because of its importance in understanding medical diagnosing. It’s not uncommon for a number of findings to exist at the same time in the same patient, but just like smaller clothes and longevity or PSA levels and farsightedness, these findings are not necessarily causative.  They may not even be related.  Often they are just coincidental.

This is particularly important when it comes to interpreting the results of imaging studies, especially very sensitive studies like MRIs.  MRI’s can be wonderful, informative and irreplaceable diagnostic tools when used properly.  Unfortunately because of their ability to identify so much detail, MRIs often reveal a lot of “noise”.  That is, not everything on the study is relevant, let alone symptomatic.

A recent study presented at the main yearly orthopedic meeting highlighted just that.  In his paper, Dr. Randy Schwartzberg confirmed what other studies had shown before.  MRIs of healthy, non symptomatic shoulders in middle aged and older patients (aged 45-60, in this study), frequently revealed a significant abnormality, one often treated with surgery. In particular, labral tears were “seen” 72% of the time and rotator cuff tears were “diagnosed” by the radiologist up to 30% of the time.  These diagnoses were identified on the MRI but may or may not have actually even been present and if present, they clearly weren’t the cause of symptoms.  After all, the imaged shoulder didn’t even have symptoms.  This phenomena is not isolated to shoulder MRIs.  It has been shown in numerous studies, in a number of body parts with all types of testing and imaging studies.

So next time you have a medical issue, remember, just because your problem appeared to develop during some particular activity or along with other symptoms, it may not have been caused by that activity or related to those additional concerns. In fact, these additional findings may at most be nothing more than indirectly related to your problem and very often, they will merely be coincidental. More importantly, these issues may not need any medical care.  So, when diagnosing and developing a treatment plan for you, everything needs to be considered in the context of your specific situation, taking all details into account. Rarely is a single test result or piece of information, by itself, enough to make a diagnosis, let alone recommend a treatment. The good docs know this…now you do too.

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