Staying up Late causes cancer?

[Monroe]

http://news.yahoo.com/s/ap/night_shift_cancer

My personal belief is this is silly. If you adapt to staying awake during the night and sleeping during the day than you should be just the same as the other way around. Now if you have a lot of infrequent work scheduels and can't get used to it than I can understand that.

[Jim]

I bet that if you look hard enought you can find a "report" that says that just about anything you can thing of causes cancer.

"Studies show that if you have a grey keyboard on your computer, you are more likely to get certain kinds of cancer" etc etc etc

[Captain Seafort]

My personal belief is this is silly. If you adapt to staying awake during the night and sleeping during the day than you should be just the same as the other way around. Now if you have a lot of infrequent work scheduels and can't get used to it than I can understand that.

Once you've adapted, sure, but your body will be stressed while you're adapting, and stress can cause all sorts of health problems. At which point, going by Sod's Law, your shift pattern will probably be changed. In addition, humans have evolved to operate during the day, so forcing it to do something it's not adapted for will also stress it.

[Tsukiyumi]

Wow. I guess I'm sort of screwed, then...

[Mikey]

Well, there may be some (precious little) chemical evidence - altered sleep patterns interfere with melatonin production a/o absorption, which can be linked to depression as in SAD - see Univ. of Ohio's light therapy studies, et. al.

However, the article is merely the latest in an alarming trend of people noticing a correlation and ASSUMING that there is a causal relationship. I will give an example. I am a type 1 diabetic; that said, though, I have educated myself about type 2 diabetes as well. There has been a huge spike in type 2 diabetes in young people in the US. According to the logic of the report we just read, and many like it, that would mean there's a "link" between type 2 diabetes and being the grandchild of a baby boomer. Is that correct? Of course not - the link is between type 2 diabetes and being a bunch of overweight, sedentary slobs.

In other words, this study found a relatively high incidence of cancer among people who work overnight shifts. That is far from evidence that the overnight shift is the CAUSE of that cancer - it merely points the direction for further research.

[Eosphoros]

I have empirical evidence that this study is wrong: I don't have cancer. No, really, I've been staying up late for the past five years. If this study was true, I'd be worm food by now.

[Sionnach Glic]

Weird. That's pretty much my only response to this.

[Mikey]

Don't let that get out the The Lancet, Eosphoros. Now, they'll being doing a study on YOU and claiming that staying up late prevents cancer.

[Eosphoros]

Unfortunately, some people don't grasp the concept of representative sample. Or any other aspect of the scientific method, for that matter.

[Tsukiyumi]

Right? My sleep schedule is non-existent, has been for at least ten years. I don't have cancer. Perhaps the people in the study were third-shift workers in occupations that exposed them to high levels of carcinogens.

[Mikey]

My point exactly - these sensationalist reports ignore the difference between coincidence and causality.

[Captain Seafort]

And you're ignoring the difference between an increased likelyhood of cancer and a guarantee that everyone who works late shifts will develop cancer. There are people who smoke like chimneys but don't develop lung cancer - does that mean that the former is not a common cause of the latter?

[Mikey]

While you're question is abviously rhetorical, you present a bad example of the point. Causality in that case has been demonstrated over long-term studies.

[Captain Seafort]

Studies like the one we're discussing. It's a known fact that stress is bad for the body, and switching your internal clock around causes stress. It's not as if it's saying that something previously thought to be perfectly healthy causes cancer (as happened back in the 50s(?) with tobacco), simply that it's an additional illness caused by unsociable working hours, and the stress thus caused.

[Mikey]

You're still missing the difference I'm trying (poorly) to explain. In the case of smoking, there is a definite causal chain of events involving biochemistry that begins with tobacco smoke and ends with lung a/o oral cancer. With this "graveyard shift" study, the only link that was found was a statistical incidence. I'm not saying that there definitely is a causal link, nor that there isn't - that's the point. As I said earlier, studies such as this absolutely point the way for further research, but they are not definitive evidence of causality in themselves.

In other words, to compare with the definitive evidence of smoking causing cancer, the research on late-shift workers a/o sleep deprivation would need to show and prove the actual chain of causal events which begins with altered sleep patterns and ends with cancer, showing at each step the processes which move the chain from one link to the next.