I wonder if it'd be possible to get data on people who are active, but not for the reason of being healthy, things like working construction, and compare that to see if it's the activity itself or just the mentality that comes from wanting to be healthy.
This may seem more surprising than it actually is, because by "overweight" and "obese" they are referring to BMI categories, according to the abstract. The overweight BMI category contains people who range from healthy, lean and muscular (think muscular gym goer) to people who have little muscle mass and high body fat percentage (think large beer belly). The fact that you can decrease cancer risk by gaining muscle (usually from increased exercise, precisely the thing being studied) and losing fat while maintaining the same physical mass and thus the same BMI, is not shocking.
Once you control for body fat, having additional muscle mass (thus higher BMI) probably decreases all-cause mortality.
Unfortunately, I don't think this has much bearing on azdle's questions, since people can be fit for many reasons, either by intent or by necessity.
It suggests people get more benefits from exercise when they expect it.
I'm curious to hear your thoughts.
> One possible explanation is that the process of learning about the amount of exercise they were already getting somehow changed the maids' behavior. But Langer says that her team surveyed both the women and their managers and found no indication that the maids had altered their routines in any way. She believes that the change can be explained only by the change in the women's mindset.
I think that they're too quick to dismiss a change in behavior. Simply asking someone (and their managers‽) if they did anything different this month than they did last month isn't a very reliable way to figure out if there were any subtle changes in behavior.
I don't know if they were expecting massive conscious changes, but I would be shocked if suddenly knowing that their daily routine is good for them didn't change some of the subconscious decisions they were making. Even just simple things like taking the stairs 10% more than they did before or how they decide when and how much to eat based on a certain level of hunger. You're still going to think "I took the stairs sometimes, but took the elevator when I needed it." or "I ate the same foods that I did before." but maybe you were taking smaller portions.
Basically what I'm trying to say is that it's very hard to draw hard quantitative conclusions from vague qualitative assessments.
Firemen, military, police, construction have high death rates.
Atheletes have drug problems.
" A total of 1.44 million participants (median [range] age, 59 [19-98] years; 57% female) and 186 932 cancers were included. High vs low levels of leisure-time physical activity were associated with lower risks of 13 cancers: esophageal adenocarcinoma (HR 0.58, 95% CI 0.37-0.89), liver (HR 0.73, 95% CI 0.55-0.98), lung (HR 0.74, 95% CI 0.71-0.77), kidney (HR 0.77, 95% CI 0.70-0.85), gastric cardia (HR 0.78, 95% CI 0.64-0.95), endometrial (HR 0.79, 95% CI 0.68-0.92), myeloid leukemia (HR 0.80, 95% CI 0.70-0.92), myeloma (HR 0.83, 95% CI 0.72-0.95), colon (HR 0.84, 95% CI 0.77-0.91), head and neck (HR 0.85, 95% CI 0.78-0.93), rectal (HR 0.87, 95% CI 0.80-0.95), bladder (HR 0.87, 95% CI 0.82-0.92), and breast (HR 0.90, 95% CI 0.87-0.93). Body mass index adjustment modestly attenuated associations for several cancers, but 10 of 13 inverse associations remained statistically significant after this adjustment. Leisure-time physical activity was associated with higher risks of malignant melanoma (HR 1.27, 95% CI 1.16-1.40) and prostate cancer (HR 1.05, 95% CI 1.03-1.08). Associations were generally similar between overweight/obese and normal-weight individuals. Smoking status modified the association for lung cancer but not other smoking-related cancers."
If it is true that exercising regularly reduces the risk of cancer, I wonder what the mechanism is? Exercise builds muscle mass, improves lung capacity... Why would that have anything to do with cancer?
2 out of 5 will get cancer during their lifetime.
Few times since I could notice that in lesser scales.
Maybe increase blood flow, increased metabolism, endorphins, etc do help keeping your system active instead of going in suspend mode while the immune system reacts alone.
Just yesterday I had this metaphor of biology being a gyroscope, the more it spins the more it can dodge.
Can someone explain the numbers? I read it as risk, sub-population, error margins. Is that right?
0.37-0.89 is the confidence interval at 95% confidence. So it's expected that if the study were repeated many times, the HR would appear to be within that (rather wide) range 95% of the time. This time it's 0.58.
The main thing is that the upper bound 0.89 is quite a bit less than 1, so you could pretty confidently say there's a reduced risk, even if the amount is uncertain.
The problem is that people's willingness to exercise depends on their health as much as or more than their health is affected by exercise. Because this study did not involve an intervention (it just pooled a bunch of surveys), it can't distinguish between exercise causing reduced cancer risk, or a third variable affecting both.
They did however:
> Body mass index adjustment modestly attenuated associations for several cancers, but 10 of 13 inverse associations remained statistically significant after this adjustment.
So even for two thin people, exercise seems to have helped. I legitimately don't see how you could design a study that you'd be satisfied with.
Adjusting for BMI does not solve the problem, because there are many things besides BMI (unmeasured confounders) which affect both cancer risk and willingness to exercise.
it's the same with red meat causes cancer studies. they say they remove smoking and lack of exercise and still wave the statistical significance.
it's very questionable how they removed the influence of these variables, since meat eaters do smoke way more, and do not exercise, and care about their health less.
I would have been happy if the authors just tried to factor in other characteristics like socioeconomic status, education level, etc. It looks like they didn't do that but instead just observed an "association" which isn't terribly interesting or informative.
The problem is the press representation of the papers as something they're not.
These types of papers should be published, because they are necessary to decide which hypotheses to test with interventional studies.
(Edit: I just re-watched his segment. He does talk about P-hacking and perverse incentives, which is at least a reasonable-size chunk of the problem, just not the failure mode for this particular study.)
This is a completely unsubstantiated claim.
Personally, staying informed and listening to my body has been my best medicine, but I'm also aware of my family history with different diseases, which helps shape my choices.
Not very many. An 8oz cup of water at 40F burns 2.1 calories to warm up to body temperature.
Do you mean "compelling"? Because it should definitely be convincing: it's well outside the margin of error.