The actual study (1) is observational and makes no causal claim, only that there exists a statistical association between caffeine consumption and dementia. Nevertheless, people are apt to misinterpret the finding as “caffeine consumption prevents dementia”:
Caffeine -> Dementia
However, the two variables would be correlated if the causal arrow were reversed and dementia influenced the propensity to consume caffeine:
Caffeine <- Dementia
And we would also observe the correlation if a person's general health influenced both the propensity to consume caffeine and dementia risk:
Caffeine <- General Health -> Dementia
Since caffeine is a stressor, we would expect to see reduced consumption among people with reduced general health. But we would also expect increased dementia among that same group. So the relationships in the diagram immediately above are plausible and would give rise to a spurious correlation between caffeine consumption and dementia risk.
While studies can try to “control for confounding factors,” it’s easy to overlook or misunderstand the true causal relationships in play, causing spurious correlations. In other words, you can create false “causal” relationships through imperfect identification and control of confounding variables.
In short, take this article’s claims with a suitable dose of suspicion.
>we would expect to see reduced consumption among people with reduced general health.
I would not expect this at all as it goes against my real world observations of people with poor general health consuming caffeine in as high doses. Some of the same causal factors for poor general health, like long work hours and long commutes can lead to increased caffeine consumption.
And "However, the two variables would be correlated if the causal arrow were reversed" is missing "also", almost suggesting that the article gets it wrong and the two variables are not correlated because of the placement of the causal arrow...
”After adjusting for potential confounders and pooling results across cohorts, higher caffeinated coffee intake was significantly associated with lower dementia risk (141 vs 330 cases per 100 000 person-years comparing the fourth [highest] quartile of consumption with the first [lowest] quartile; hazard ratio, 0.82 [95% CI, 0.76 to 0.89]) and lower prevalence of subjective cognitive decline (7.8% vs 9.5%, respectively; prevalence ratio, 0.85 [95% CI, 0.78 to 0.93]).”
So about 18% relative reduction. But if your risks are already low (e.g. active and healthy diet) the relative reduction is less impactful (e.g. 4% to 3.28%).
Makes you wonder. Coffee is tasty, so we drink it, and find out much later it also has these awesome side effects. What if there are plants out there that have even better health effects, but we'll never get decades worth of data on their consumption because they taste bad?
Brussels have chemically changed significantly over the past 20 years of genetic engineering - they're more nutritious than ever and are nowhere near as bitter!
Only to the extent that the growers who apply deliberate selection criteria are themselves part of "nature". But we generally use that term to distinguish outcomes for which human intentions weren't a causal determinant, so I don't think it makes sense in this case.
But natural evolution is also selective. Animals choose their partners based on looks or features, they eat the fruits that look the best, spreading those seeds, and bees go to the most colorful flowers. Same thing we do
They taste bad to some people, apparently. I like them, as well as all the other cultivars of the Brassica oleracea species, like kale, broccoli, cabbage, and cauliflower.
Is that right? Isn't it more related to the fact that people in education/etc. actually drink more coffee for culture reasons but also use their brain more? could that be the actual reason? Because I don't see how all the coffee zombies in my workplace would last longer long term when they're already useless and aggressive today (until they had their coffee)
This was a follow-on to a study of nurses showing coffee drinkers have lower all cause mortality.
Caffeine has been shown to exert effects via adenosine receptor antagonism and influence on cAMP & AMPK pathways. These same pathways are implicated in a lot of issues with aging. Caffeine also has some anti-inflammatory properties and Coffee beans are a strong anti-oxidant though I don't really think that matters much.
> Caffeine has been shown to exert effects via adenosine receptor antagonism and influence on cAMP & AMPK pathways. These same pathways are implicated in a lot of issues with aging.
That is like saying biological pathways are implicated in aging (because you said "pathways").
In any case, adenosine receptor antagonism has a pretty weak link if any to aging.
Additionally, we say that about virtually everything that is herbal, that it has anti-inflammatory properties. You are right, it does not matter at all.
Yes, without a good experiment (maybe a natural one [1]) we can't know. Even if the study controls for everything observable, there may be unobserved differences that lead to the caffeination difference. For instance, even though two people might have the same job, education, etc. the one who is more ambitious, or creative, or hopeful, or simply healthy enough to feel like working more, might drink more coffee.
Teasing out causation with empiricism is near impossible without eventually needing to rely on occum's razor to some extent or another.
Reliance on occum’s razor would probably be less needed if this was a random control trial, but still the study would be correlative with alternative explanations still plausible.
Regarding health, focus on calorie control and getting enough fats/carbs/protein. Eat whole foods that are high enough on the satiety index because they make calorie maintenance more intuitive so you don’t have to count calories if you don’t want to. Those (and maybe a few other tips) are the only things that have a large enough effect for one to determine with almost (only almost, because everything empirical is a confidence interval/correlation) certainty that they’re effective.
Any study saying that blueberries are “superfoods” or any other hyper-specific food recommendation, I immediately don’t trust it. There just isn’t any organization that would fund a RTC of such a niche finding, especially considering you would need to pay and surveil thousands of people over the course of their whole life to change their diet and stick to it. I don’t think even the NIH is giving out millions of dollars to a research team to find out if blueberries are superfoods.
Coffee, like other beans, is loaded to the hilt with antioxidants, particularly once it’s hyper-concentrated, and the roasting and brewing process eliminates all the mechanisms beans normally use to avoid animals wanting to eat them.
Isn't this all about brain hypoperfusion coming from some sort of dysautonomia and/or mitochondrial dysfunction and worse blood vessels as we age? We know that medication that helps blood flow and endothelium improves brain long-term, like sildenafil.
Only a few years ago, there was a study showing that regular caffeine use reduces blood flow to the brain by up to 30%, leading to lower brain volume and increased risk of dementia.
"Excessive coffee consumption was significantly associated with an increased risk of all-cause neurodegenerative diseases and vascular neurodegenerative diseases. The results also showed that tea intake was associated with a reduced risk of all-cause neurodegenerative disease, vascular neurodegenerative disease, other neurodegenerative diseases, and VD. Moreover, coffee and tea had an interactive relationship with all-cause neurodegenerative diseases and AD, with specific combinations significantly associated with reduced risk of disease" onset.
The actual study (1) is observational and makes no causal claim, only that there exists a statistical association between caffeine consumption and dementia. Nevertheless, people are apt to misinterpret the finding as “caffeine consumption prevents dementia”:
Caffeine -> Dementia
However, the two variables would be correlated if the causal arrow were reversed and dementia influenced the propensity to consume caffeine:
Caffeine <- Dementia
And we would also observe the correlation if a person's general health influenced both the propensity to consume caffeine and dementia risk:
Caffeine <- General Health -> Dementia
Since caffeine is a stressor, we would expect to see reduced consumption among people with reduced general health. But we would also expect increased dementia among that same group. So the relationships in the diagram immediately above are plausible and would give rise to a spurious correlation between caffeine consumption and dementia risk.
While studies can try to “control for confounding factors,” it’s easy to overlook or misunderstand the true causal relationships in play, causing spurious correlations. In other words, you can create false “causal” relationships through imperfect identification and control of confounding variables.
In short, take this article’s claims with a suitable dose of suspicion.
(1) https://jamanetwork.com/journals/jama/article-abstract/28447...
>we would expect to see reduced consumption among people with reduced general health.
I would not expect this at all as it goes against my real world observations of people with poor general health consuming caffeine in as high doses. Some of the same causal factors for poor general health, like long work hours and long commutes can lead to increased caffeine consumption.
This is an amazing explanation and I am going to keep it on hand for future use. In the first sentence causal is typoed as casual
And "However, the two variables would be correlated if the causal arrow were reversed" is missing "also", almost suggesting that the article gets it wrong and the two variables are not correlated because of the placement of the causal arrow...
Thanks for your kind words! And thanks for reporting the typo (now fixed).
Actual study: https://jamanetwork.com/journals/jama/article-abstract/28447...
”After adjusting for potential confounders and pooling results across cohorts, higher caffeinated coffee intake was significantly associated with lower dementia risk (141 vs 330 cases per 100 000 person-years comparing the fourth [highest] quartile of consumption with the first [lowest] quartile; hazard ratio, 0.82 [95% CI, 0.76 to 0.89]) and lower prevalence of subjective cognitive decline (7.8% vs 9.5%, respectively; prevalence ratio, 0.85 [95% CI, 0.78 to 0.93]).”
So about 18% relative reduction. But if your risks are already low (e.g. active and healthy diet) the relative reduction is less impactful (e.g. 4% to 3.28%).
> the relative reduction is less impactful (e.g. 4% to 3.28%
That's also an 18% reduction
I think what he means is a reduction of 18% based on 4% is way less than 18% based on 80%.
Percents of percents always felt kludgey.
Log probabilities (like decibans) unify this to say there is a -0.86 dB risk reduction for everybody.
https://rationalnumbers.james-kay.com/?p=306
It makes the math of combining risks easier and works the same even if we're operating near 99.999% or 0.0001%
That’s exactly my point.
If someone is high risk, say 20%, then an 18% drop from that is 14.4%. That may justify picking up caffeine.
But if you’re otherwise healthy, picking up caffeine has diminishing returns, and the downsides may not be worth it.
Makes you wonder. Coffee is tasty, so we drink it, and find out much later it also has these awesome side effects. What if there are plants out there that have even better health effects, but we'll never get decades worth of data on their consumption because they taste bad?
You just described brussels sprouts !
(they too can get quite tasty in the oven though)
Brussels have chemically changed significantly over the past 20 years of genetic engineering - they're more nutritious than ever and are nowhere near as bitter!
They are not genetically engineered, it’s mostly just selective breeding.
Is selective breeding not a form of genetic engineering?
No. If so, you'd had to put a GMO label on all cultivated food.
Isn’t nature genetic engineering then? Amazing genetic engineering nature?
I'd argue evolution is a mechanism that nature uses to engineer genetics, sure
Only to the extent that the growers who apply deliberate selection criteria are themselves part of "nature". But we generally use that term to distinguish outcomes for which human intentions weren't a causal determinant, so I don't think it makes sense in this case.
But natural evolution is also selective. Animals choose their partners based on looks or features, they eat the fruits that look the best, spreading those seeds, and bees go to the most colorful flowers. Same thing we do
Especially when you drizzle them with balsamic vinegar!
Try caesar dressing
They taste bad to some people, apparently. I like them, as well as all the other cultivars of the Brassica oleracea species, like kale, broccoli, cabbage, and cauliflower.
Is that right? Isn't it more related to the fact that people in education/etc. actually drink more coffee for culture reasons but also use their brain more? could that be the actual reason? Because I don't see how all the coffee zombies in my workplace would last longer long term when they're already useless and aggressive today (until they had their coffee)
This was a follow-on to a study of nurses showing coffee drinkers have lower all cause mortality.
Caffeine has been shown to exert effects via adenosine receptor antagonism and influence on cAMP & AMPK pathways. These same pathways are implicated in a lot of issues with aging. Caffeine also has some anti-inflammatory properties and Coffee beans are a strong anti-oxidant though I don't really think that matters much.
> Caffeine has been shown to exert effects via adenosine receptor antagonism and influence on cAMP & AMPK pathways. These same pathways are implicated in a lot of issues with aging.
That is like saying biological pathways are implicated in aging (because you said "pathways").
In any case, adenosine receptor antagonism has a pretty weak link if any to aging.
Additionally, we say that about virtually everything that is herbal, that it has anti-inflammatory properties. You are right, it does not matter at all.
Yes, without a good experiment (maybe a natural one [1]) we can't know. Even if the study controls for everything observable, there may be unobserved differences that lead to the caffeination difference. For instance, even though two people might have the same job, education, etc. the one who is more ambitious, or creative, or hopeful, or simply healthy enough to feel like working more, might drink more coffee.
https://en.wikipedia.org/wiki/Natural_experiment?wprov=sfla1
The studies compared people from the same occupation, so no, that is not likely the reason
But that can still not account for cultural/work ethic differences.
Exactly. Just another “study” finding a correlation without causation.
Teasing out causation with empiricism is near impossible without eventually needing to rely on occum's razor to some extent or another.
Reliance on occum’s razor would probably be less needed if this was a random control trial, but still the study would be correlative with alternative explanations still plausible.
Regarding health, focus on calorie control and getting enough fats/carbs/protein. Eat whole foods that are high enough on the satiety index because they make calorie maintenance more intuitive so you don’t have to count calories if you don’t want to. Those (and maybe a few other tips) are the only things that have a large enough effect for one to determine with almost (only almost, because everything empirical is a confidence interval/correlation) certainty that they’re effective.
Any study saying that blueberries are “superfoods” or any other hyper-specific food recommendation, I immediately don’t trust it. There just isn’t any organization that would fund a RTC of such a niche finding, especially considering you would need to pay and surveil thousands of people over the course of their whole life to change their diet and stick to it. I don’t think even the NIH is giving out millions of dollars to a research team to find out if blueberries are superfoods.
Coffee, like other beans, is loaded to the hilt with antioxidants, particularly once it’s hyper-concentrated, and the roasting and brewing process eliminates all the mechanisms beans normally use to avoid animals wanting to eat them.
- coffee seeds are not actually 'beans'
- caffeine is the main mechanism it uses to deter pests like insects, definitely not removed in the roasting and brewing process
- like many fruits, they're sweet and nutritious, encouraging larger animals to eat it
- the stuff marketed as dietary antioxidants still hasn't been shown to improve anything
what are you talking about
Original source: https://jamanetwork.com/journals/jama/article-abstract/28447...
Then again if you have dementia, you are highly likely to lesve the office environment and any study, thus reversing causality.
What do you believe an “office environment” has to do with this?
FTA:
> “Researchers from Mass General Brigham tracked more than 130,000 people for over four decades”
Does not apply to the White House
Isn't this all about brain hypoperfusion coming from some sort of dysautonomia and/or mitochondrial dysfunction and worse blood vessels as we age? We know that medication that helps blood flow and endothelium improves brain long-term, like sildenafil.
Only a few years ago, there was a study showing that regular caffeine use reduces blood flow to the brain by up to 30%, leading to lower brain volume and increased risk of dementia.
Caffeine -> Suppresses appetite -> Lowers Caloric Intake -> Reduces Cell Turnover -> Prevents Dementia ?
Counterpoint
"Consumption of coffee and tea and the risk of developing neurodegenerative diseases: a cohort study in the UK biobank"
https://link.springer.com/article/10.1186/s12937-026-01291-0
Conclusions
"Excessive coffee consumption was significantly associated with an increased risk of all-cause neurodegenerative diseases and vascular neurodegenerative diseases. The results also showed that tea intake was associated with a reduced risk of all-cause neurodegenerative disease, vascular neurodegenerative disease, other neurodegenerative diseases, and VD. Moreover, coffee and tea had an interactive relationship with all-cause neurodegenerative diseases and AD, with specific combinations significantly associated with reduced risk of disease" onset.
That’s not a counterpoint, because the OP study is not referring to “excessive” coffee consumption:
> “the apparent benefits weren't tied to heroic levels of caffeine intake, just to steady, mid-range consumption – roughly two to three cups a day”
Does decaf have the same effects ?
You'd be missing out on the anti-inflammatory properties of the caffeine, so maybe it might have some effect?
My bowels disagree, caffeine make them feel inflammatory
High fiber foods can make your tummy feels inflammatory, that doesn't mean they're not highly beneficial for you
The problem which I omitted is that I have IBS mixed type, so high fiber diet literally makes me a bomb lol.
No, only caffeinated
> decaffeinated coffee intake was not associated with lower dementia risk or better cognitive performance
Coffee is the biggest trojan horse....