[d_burfoot]

In about 100 years, people will realize that this kind of research doesn't actually work.

Here's the problem: the human body is an immensely complex system, with millions of factors influencing its status and well-being. Untangling these factors correctly and producing an accurate and sophisticated statistical theory of the body would require a comparably large number of parameters - on the order of millions or more.

Unfortunately, modern medical science relies on low-N observational or clinical trials, with N on the order of hundreds or thousands. In this radically low-data regime it is impossible to justify the use of complex models. If you try to use a complex model, you will just get overfitting. You can use a simple model to avoid overfitting, but there's no reason to believe that a simple model will produce a good approximation of the underlying dynamics.

[maxander]

Happily, these kinds of studies aren't attempting to create a comprehensive statistical model of the human body, in any reasonable sense- they're just asking, "if we change X in modern human lifestyle, and leave every other factor within the range of typical variation, how does it change Y?" Thus, in almost every case, the millions of other factors influencing human wellbeing can be completely ignored for the purposes of the study, as long as they're reasonably well represented in the study population.

In terms of caffeine studies, yes- there are definitely thousands of other foods and so-forth that effect the risk of heart disease, cancer, and whatever else they're looking at. There's even things which interact with caffeine specifically to modulate or plausibly even reverse it's effects. All of these things work in egregiously complicated ways. But when I read the study and try to think what it tells me about my own situation, this doesn't matter since I can usually assume that my own exposure to these other factors will be typical compared to that of the study population- thus, I'll tend to respond similarly to caffeine as they did.

This approach is obviously has an abundance of limitations- it only tells me how I'm more likely to respond to caffeine or whatever else, but doesn't give any guarantees. And for someone who is different than the study population- a black woman living in Uganda versus a study done on white male freshmen at Yale, say- the results rapidly become less meaningful. But they do work.

[notahacker]

Yep. The epitome of this is the infamous Finnish researcher who conducts ostensibly reasonable statistical analysis in order to prove his desired contrarian conclusion that it's beneficial to drink up to six pints of regular strength beer every day, and harmful to have days off drinking...

Even if a model actually succeeds in properly balancing the controls so that as well as controlling for basic demographics it also ensures its non coffee drinkers don't drink a commensurately larger portion of other caffeinated drinks or unhealthy alternative drinks or substitute for the caffeine hit with stronger drugs, and don't have a health reason for cutting caffeine or a cultural/social reason linked to other behaviours or diets, you've then got the problem that people with different genes and physical health likely metabolise coffee in very different ways, and to recommend more or less coffee to a particular individual, you've probably got to untangle all that too...

[cJ0th]

I've never understood this phenomena myself. Those who do this kind of research on a daily basis must have been rather smart to get their job. Surely, they must be intelligent enough to realize that what they do does not really add up to much?

[Asooka]

Publish or perish.

[retroafroman]

I'm definitely an amateur at understanding biology, but having studied engineering; the inputs and outputs of the human body vary so widely that I have a hard time narrowing down one input to corresponding to one result.

When you think about the air you breathe, to the variety of things you ate (plus the additional microbiomes that inhabit the food, your skin, your gut, etc) it seems like we are just barely really understanding what the intakes to the body are.

Edit: here's a great point to start to think about it: https://youtu.be/bYOIhmZ0Osg?t=41m49s -watch for 10m

[Nydhal]

In some sense traditional medicine or traditional\religious healthy habits (I'm thinking something like kashrut) has way larger sample since it's been practiced for millenia and its populations still survived enough to transmit them to offspring. If grandma made it long enough to teach the grand kids some old traditions there's probably some merit to some of them.

[Chickenosaurus]

The only thing that can be deduced from this observation is that these traditions are not deadly in the short term. After all, smoking is a tradition in some cultures, even though we are sufficiently certain smoking is harmful.

[bjourne]

Circumcision is practiced by billions, yet there is no health benefits at all.

[refurb]

That's not true at all. Circumcision is linked to lower rates of penile cancer, lower rates of STD infection (probably why cancer rates are lower) particularly HIV and lower rates of bladder infections. In fact it was recommended that circumcision be standard practice in areas of Africa with high HIV rates.

[bjourne]

Read this article, it demolishes the "health benefits" argument: http://blogs.bmj.com/medical-ethics/2017/08/15/does-female-g... In short, if male circumcision has health benefits, then female circumcision has too and even African tribes' rituals in which they pull each others teeth out because it prevents tooth decay!

Regardless of that, and assuming that there are major health benefits to circumcision, the Jewish and Muslim communities that practiced it for millennia, couldn't possibly have been aware of any. Because they didn't perform any epidemiological studies measuring rates of penile cancer and HIV infections. But they must have noticed a lot of babies and boys getting fevers and dying from infections shortly after the procedure was performed on them. Clearly, the rite lived on because "God told them to" despite the adversarial effects it had on their children's health.

[throwanem]

Can you cite some substantiation for the claim of high morbidity and mortality historically resulting from circumcision of male neonates? I'm not tremendously in favor of the practice myself, as it seems unnecessarily traumatic, but I also think it's worth paying heed to the occasional fact, no matter how firmly you happen to be against it.

And I'm not especially impressed by that article you linked, either. Several of the sources it cites in support of its arguments, when examined, turn out to be tangentially related at best, and not at all supportive of the claims to which they're linked.

[whiddershins]

Do you really think mutilating people’s genitalia is a reasonable intervention to lower STD rates?

It’s my opinion that circumcision acceptance is based on a cultural/ideological blind spot.

[Jyaif]

Less STDs because of the hardened skin. Look it up.

[fabatka]

I completely agree. Also, with a pop-science-y title like this, how can anyone take the article seriously?