Have you ever wondered whether being smart, causes you to live a healthier life (on average)? I mean you're a pretty smart person right? Wouldn't you like to know if your smart brain actually causes you to have a longer life? A lower chance of cancer maybe? Less chance of illness perhaps? I mean, thinking logically there is a basis for why it could! If you are smarter you are more likely to know about things that could cause disease and make a conscious effort to avoid them. Yet the more one knows and understands the more there is to stress about, and stress is highly associated with negative health outcomes. [[1](http://www.apa.org/helpcenter/stress.aspx)] However maybe ignorance is bliss and not knowing about things leads to more active, fulfilled, healthier lives. Maybe intelligence is a curse, a burden on our health. What about our genes themselves, might they have a say in all of this?

<center>![](https://steemitimages.com/DQmV8F3BhRdj1QQdfcnGwwrApAA5MPxRp7McUYQFMyJz2cV/image.png)</center>
<center>[The Famous "Thinking Man" Statue Was Probably Pondering This Himself](https://upload.wikimedia.org/wikipedia/commons/a/ad/ThinkingMan_Rodin.jpg)</center>

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# The Cold Reality

This isn't a new concept, people have been looking for more ways to assert themselves as superior for a long time (and I am sure that is a fad which isn't going anywhere). So not surprisingly this is a topic that has been studied in quite some detail. Luckily for all of you **smart** steemians (even if you don't think you are, you're here so your clearly smarter than a lot of people), low intelligence along with minimal education has already been shown to be correlated with poor health. [[2](https://academic.oup.com/ije/article-lookup/doi/10.1093/ije/dyq190)], [[3](http://www.sciencedirect.com/science/article/pii/S0160289615001014)], [[4](http://www.who.int/hia/evidence/doh/en/)]. However these studies have only largely shown the correlation, they didn't look into why this correlation exists.  

<center>https://media.giphy.com/media/MHmquXsUF1H1e/giphy.gif</center>

In still other publications, researchers looked at whether how educated someone is acts as a means for measuring intelligence, finding that that indeed yes education level correlates to intelligence. [[5](http://onlinelibrary.wiley.com/doi/10.1111/j.1468-0297.2012.02499.x/abstract)] (Some of you are going... well that correlation is obviously wrong, you're highly educated @justtryme90 and I think you're an idiot... to that I would respond... yeah you're probably right!). Going further researchers have identified that there is even a genetic link between intelligence and education level. [[6](http://onlinelibrary.wiley.com/wol1/doi/10.1002/ajmg.b.32319/full)] However all of these findings report correlation, and as we know:

<center>![](https://steemitimages.com/DQmPnXiWTgC6qFQLMSTetRFJpv7MWmuquX3f1fjqjG4GVxJ/image.png)</center>
<center>[CORRELATION DOES NOT NECESSARILY MEAN CAUSATION](https://c1.staticflickr.com/2/1451/25050350313_3174bc96b4.jpg)</center>

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# Today's Article

In a study published June 1st, 2017 in the journal [Nature: Scientific Reports titled "Cognitive ability and physical health: a Mendelian randomization study"](https://www.nature.com/articles/s41598-017-02837-3) researchers set out to examine the causal links between our thinking abilities and our health. Rather than just correlation, could they identify some causation?

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# Does Poor Health Cause Lower Intelligence?

This is perhaps an easier direction to study, all you need are some healthy people, some people with various diseases and a test to measure their brain power.

<center>https://media.giphy.com/media/p5IGmZWMNcfgQ/giphy.gif</center>
<center> The test wasn't weightlifting, sorry cartoon brain</center>

For the test they used a simple multiple choice test with some verbal and some numerical based questioning, they give an example of each in their materials and methods:

> An example verbal item is: ‘If some flinks are plinks and some plinks are stinks then some flinks are definitely stinks?’ (possible answers: ‘True/False/Neither-true-nor-false/do not know/prefer not to answer’). 

>An example numerical item is: ‘If sixty is more than half of seventy-five, multiply twenty-three by three. If not subtract 15 from eighty-five. Is the answer?’ (possible answers: ‘68/69/70/71/72/do not know/prefer not to answer’).

The participants had to answer 13 of these in 2 minutes, not an easy task, it would take me 2 minutes just to get past flinks and plinks...but I digress.


## What Did They Find?

- Height was directly associated with intelligence, with taller people scoring better than shorter people
- Both high blood pressure and type two diabetes were negatively associated with intelligence but not nearly as sharply as coronary heart disease which had a surprisingly significant effect.

To check for causal relationships the authors used a technique called ["Mendelian Randomization"](https://en.wikipedia.org/wiki/Mendelian_randomization), however for these health variables they **didn't find ANY at all**.

So while poor health correlates with lower intelligence, the authors **didn't** find evidence suggesting that it **causes** it. (hmm, I sort of expected that they would find that it does... but the data is the data! On we go!)

# How About Education And Health?

This analysis was performed by looking at health information and education levels reported and stored in a database. For this part of the study over 90,000 people were included 

Looking at people who had very little education (the article calls it 7 years) versus people with a college degree (the article calls it 20 years) the authors found that people with more education had the following:

- Lower body mass index 
- Lower odds of diabetes
- Lower odds of coronary heart disease
- Lower blood pressure

and the weird one... educated people were more likely to be taller. What?

<center>http://media.giphy.com/media/doJrCO8kCAgNy/giphy.gif</center>

However again as was the case for the above correlations, their Mendelian randomization analysis did not show any causation between education and these positive health outcomes. Sorry educated people.

# Some Conclusions

This study set out to identify if there were causal relationships between previously described correlations between intelligence, education and health. They again identified these correlations, however their analysis yielded NO evidence of causation.

**Intelligence correlates to better health, but intelligence is not the CAUSE of better health outcomes.**

The authors speculate provided a variety of reasons for why they may not have seen any evidence of causation in their study and proposed avenues forward for research. I don't doubt that research in this area will continue. However at the moment, smart and educated people, your brains correlate to better health outcomes, but are not the cause of any of it. That part, is still all up to you and the decisions you make with regards to taking care of your self.

### Other Conclusion

Taller people are "smarter". 

<center>https://media.giphy.com/media/NyvaiYod2ShwI/source.gif</center>
<center>Except for you Tyrion, except for you.</center>


# Sources

1) http://www.apa.org/helpcenter/stress.aspx
2) https://academic.oup.com/ije/article-lookup/doi/10.1093/ije/dyq190
3) http://www.sciencedirect.com/science/article/pii/S0160289615001014
4) http://www.who.int/hia/evidence/doh/en/
5) http://onlinelibrary.wiley.com/doi/10.1111/j.1468-0297.2012.02499.x/abstract
6) http://onlinelibrary.wiley.com/wol1/doi/10.1002/ajmg.b.32319/full
7) https://www.nature.com/articles/s41598-017-02837-3



**All Non Cited Images Are From Pixabay.com And Are Available Under Creative Commons Licenses**

**Any Gifs Are From Giphy.com and Are Also Available for Use Under Creative Commons Licences**

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If you like this work, please consider giving me a follow: @justtryme90. I am here to help spread scientific knowledge and break down primary publications in such a way so as to cut through the jargon and provide you the main conclusions in short (well compared to the original articles at least!) and easy to read posts.