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We’re learning more about the differences in health between early risers and night owls, and new research could offer even more evidence that vaping is just different from smoking, not necessarily better.

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[♪ INTRO].

Look, night owls have it rough. In addition to the fact that society refuses to let them follow their natural sleep schedule, scientists also keep publishing all this grim research telling them they might die sooner than early birds.

Well, no wonder they can’t fall asleep. But according to the latest study of the genetics of chronotypes, that’s the technical term for whether you’re an early bird, or a night owl, or somewhere in between, the results are a little more of a mixed bag. Lots of outside factors can affect your sleep habits, like your work schedule or your exposure to light.

But whether you're a morning person can also be more of a built-in genetic thing. This latest study, published this week in the journal Nature Communications, discovered more than 300 new genes connected to chronotype. It also found that morning people had greater overall well-being and a lower risk of certain mental health disorders.

But surprisingly, this research didn't find that being a natural night owl could lead to obesity or Type 2 diabetes, even though other studies have shown a connection between those health problems and sleep habits. The team looked at nearly 700,000 participants, drawn from a research database in the UK and people who had sent in their DNA for analysis by a private company. All of these people also had also been asked to report their chronotype.

From the participants’ genetic data, the researchers were able to identify 351 genetic markers associated with being an early or late riser, only 24 of which had been previously identified. These newly IDed genes were involved with everything from circadian rhythms to the development of neurons to retinal tissue. There’s a lot more to explore when it comes to what all these genes do, but the researchers think changes to the retina, for example, could affect how light recalibrates your body clock, which could affect what time of day you get sleepy.

Previous studies had suggested links between chronotype and things like mental health, weight, and Type 2 diabetes risk, so the researchers chose to focus on those health risks in their analysis. Using advanced statistics, they were able to analyze more than just correlations, they could actually calculate whether one thing was likely to cause another. And they found that being an early bird strongly predicted a better overall sense of well-being, as well as a lower risk of depression and schizophrenia.

But they didn’t find that genetic chronotype predicted obesity or diabetes, even though they’ve long been reported to be linked to circadian rhythms. These findings don’t mean those links are wrong, people who go to sleep and wake up later are still more likely to have obesity or Type 2 diabetes. But the connection could be less about your natural tendency to sleep later and more about non-genetic factors, like having to wake up early despite being a natural night owl.

Or, these conditions could be affecting people’s sleep patterns, rather than the other way around. There are lots of possible explanations for the association, we just don’t know. So we still have a lot more to learn, but with the huge database of genetic data researchers are compiling, we’re starting to be able to answer questions we never could before.

Speaking of really big health studies, researchers from the School of Medicine at the University of Kansas in Wichita may have some bad news about e-cigarettes. Their findings, based on what 400,000 survey respondents reported about a wide range of health behaviors and problems, suggest that using e-cigarettes is linked to a higher risk of stroke, heart attack, and just heart disease in general. For those of you who have continued to Just Say No, and also been hiding under a rock, the kerfuffle over e-cigarettes began about a decade ago.

They were pitched as a healthier alternative to smoking tobacco, and they are? E-cigarettes, or e-cigs, or vape pens heat a nicotine-packed liquid into a vapor that can be inhaled by the user, which gives them all of the buzz and none of the smoke and tar that comes from traditional cigarettes. But since they’re so new, we don’t know nearly as much about the health effects of e-cigarettes as we do regular cigarettes.

But we do know that they’re definitely not better than not smoking at all. And their fun flavors and reputation as being quote-unquote “safe” and also cool fun hip designs has made them a little more popular these days with the middle and high school crowds. In 2016, 11% of high school students reported having used e-cigarettes, 9 times more than in 2011.

There has also been research that suggests inhaling the flavorings in e-cig juice can be toxic. So that’s not great. And these new results could offer even more evidence that vaping is just different from smoking, not necessarily better.

Of the 400,000 respondents to the 2016 health survey the researchers analyzed, nearly 67,000 of them were e-cig users. Compared to the 333,000 non-vaping controls, the e-cigarette users had a 71% higher risk of stroke, a 59% higher risk of heart attack or reduced blood flow to the heart, and a 40% higher risk of coronary heart disease. A little over 4% of the users had already suffered a stroke.

While this certainly seems like a dire warning for e-cigarette users, there are a couple of important things to consider. First, the e-cigarette users were also twice as likely to be regular cigarette smokers. Which… could be a pretty big confounding factor, since smoking tobacco also puts you at risk for stroke, heart attack, and heart disease.

To really see the effects of e-cigs on their own, future studies will have to do a better job of separating the people who use them from those who use regular cigarettes. And secondly, this research is still preliminary. While it’s being presented at a scientific conference next week, it hasn’t been peer reviewed yet, which means there could still be problems with it.

That probably won’t stop it from making the headlines, and it does not mean the results should be discounted. But it does mean we shouldn’t just accept them at face value without waiting to see the final paper. What we do definitely know is that nicotine remains addictive, so watch out for that.

Thanks for watching this episode of SciShow News! If you’re interested in keeping up with groundbreaking discoveries like these or you want to learn more about all the most fascinating science out there, you are in the right place! Just go to and click on that subscribe button. [♪ OUTRO].