4 ms·

I'm going to completely disregard this study. "What would the world look like if this study were true?" 53% is such a large effect size that if the study were

I'm going to completely disregard this study. "What would the world look like if this study were true?" 53% is such a large effect size that if the study were anywhere near accurate, I'd expect to have seen many other similar studies, and other knock-on effects (nothing in the body is isolated, even dementia). But we all know that studies routinely find no or only positive health benefits associated with drinking coffee. I bet this study is junk.

jlmorton 5y ago
I don't really disagree with you, but 53% is not that enormous of an effect. To put this in perspective, tobacco smoking raises the risk of lung cancer by about 3000%.
EMM_386 5y ago
Every time I see studies like this it reminds me of the Roche Biochemical Pathways http://biochemical-pathways.com/#/map/1 http://biochemical-pathways.com/#/map/1 For starters, there are over 1000 chemical compounds in coffee. For a 53% effect, let's toss out "coffee" and go with a specific compound. Are we talking about pH effects? The possible carcinogens with roasting? Caffeine? Does Diet Coke have this effect? The fertilizer used during growing? Does coffee candy with natural flavor have this effect? After that, how do the biochemical pathways and inherent homeostasis handle this change? Forget it. The rabbit hole is endless with studies like this.
cmeacham98 5y ago
It should be noted that "too much" is 6 cups per day, which I suspect very few people drink consistently.
- AuthorizedCust 5y ago
  Really? A common measurement standard for a cup of coffee is 6 oz. If this is a 6 oz cup of normal-strength (i.e., weak) coffee, then that's only 36 oz, or three soda cans. What if you consume what's now considered normal, which seems quite strong? Two soda cans? How large is a mug, which people associate conceptually with "a cup"?
  - melbourne_mat 5y ago
    I think it would be the amount of caffeine per cup. My guess is that a standard coffee cup would be 80-100mg. 600mg is a hell of a lot of caffeine - on rare days when I have 400 I feel very well used at the end of the day.
- satori99 5y ago
  Damn. Now I'm worried. Consuming less than 6 coffees a day is more unusual for me.
tomxor 5y ago
The statistic is relative: "a 53% increase" is relative to some baseline. It does not mean the absolute risk is raised to 53%. Without context these relative form are meaningless, and they are presented this way annoyingly commonly by media. For example if the baseline absolute risk is 0.0100% then the study suggests the increase would raise that to 0.0153% in absolute terms... and no I do not know what the baseline is, the headline is truly meaningless to me.
- tommiegannert 5y ago
  Figure 2 of the study says the ">6 cups/day" cohort had 123 of 9,265 dementia cases (1.3%). The "1-2 cups/day" reference group had 953 of 123,516 dementia cases (0.77%).
  - tomxor 5y ago
    hah, so my exaggerated example was only 1 order of magnitude off.
weare138 5y ago
I agree, this contradicts several studies that concluded the opposite. Here's a couple I found after a quick search: There were no significant associations between coffee or caffeine intake and risk of cognitive impairment, overall dementia, AD, VaD, or moderate/high levels of the individual neuropathologic lesion types. https://content.iospress.com/articles/journal-of-alzheimers-disease/jad101428 https://content.iospress.com/articles/journal-of-alzheimers-... Coffee drinkers at midlife had lower risk of dementia and AD later in life compared with those drinking no or only little coffee adjusted for demographic, lifestyle and vascular factors, apolipoprotein E ε4 allele and depressive symptoms. https://content.iospress.com/articles/journal-of-alzheimers-disease/jad00920 https://content.iospress.com/articles/journal-of-alzheimers-...
unparagoned 5y ago
When people wonder how others can get stuck in their own echo chamber, remember this post. They didn't read the article, misinterpreted the stats, and just ignored the results since it didn't conform to their preconceptions.
melbourne_mat 5y ago
I think you missed the "6+ coffees a day" part.
tommiegannert 5y ago
It seems this is not the first study. The introduction says >A Mendelian randomisation study has provided evidence for a potential adverse effect of higher coffee consumption on the risk of Alzheimer’s disease, with each cup of coffee increasing the risk by 26% (13). However, observational evidence is inconsistent, and of the 11 most recent longitudinal cohort studies on habitual coffee intake and dementia risk, five supported a possible protective effect (14–18), whereas six studies found no association (19–24). ... and it looks like we have a long way to go before there's a conclusion.
vixen99 5y ago
On the other hand, caffeine is a vaso-constrictor which reduces blood supply to the brain. This is very old news and replicated many times from even 1935. What are the effects of this? To go full forward we have https://www.biorxiv.org/content/10.1101/2021.07.01.450708v1.full.pdf https://www.biorxiv.org/content/10.1101/2021.07.01.450708v1.... (July 2 2021) "Our findings unveil that conventional daily caffeine intake does not provide sufficient time to clear up psychoactive compounds and restore cerebral responses, even after 36 hours of abstinence. They also suggest investigating consequences of a paraxanthine accumulation during daily caffeine intake." As an avid coffee drinker I'd like to feel able to agree with your conclusion but I'll limit the amount wagered. https://pubmed.ncbi.nlm.nih.gov/19219847/ https://pubmed.ncbi.nlm.nih.gov/19219847/ Coffee has a lot of other components such as polyphenols which generally have a beneficial effect. May be that this counteracts the possible negative consequences of caffeine under certain conditions.

jlmorton 5y ago

I don't really disagree with you, but 53% is not that enormous of an effect. To put this in perspective, tobacco smoking raises the risk of lung cancer by about 3000%.

EMM_386 5y ago

Every time I see studies like this it reminds me of the Roche Biochemical Pathways http://biochemical-pathways.com/#/map/1 http://biochemical-pathways.com/#/map/1 For starters, there are over 1000 chemical compounds in coffee. For a 53% effect, let's toss out "coffee" and go with a specific compound. Are we talking about pH effects? The possible carcinogens with roasting? Caffeine? Does Diet Coke have this effect? The fertilizer used during growing? Does coffee candy with natural flavor have this effect? After that, how do the biochemical pathways and inherent homeostasis handle this change? Forget it. The rabbit hole is endless with studies like this.

cmeacham98 5y ago

It should be noted that "too much" is 6 cups per day, which I suspect very few people drink consistently.

AuthorizedCust 5y ago
Really? A common measurement standard for a cup of coffee is 6 oz. If this is a 6 oz cup of normal-strength (i.e., weak) coffee, then that's only 36 oz, or three soda cans. What if you consume what's now considered normal, which seems quite strong? Two soda cans? How large is a mug, which people associate conceptually with "a cup"?
- melbourne_mat 5y ago
  I think it would be the amount of caffeine per cup. My guess is that a standard coffee cup would be 80-100mg. 600mg is a hell of a lot of caffeine - on rare days when I have 400 I feel very well used at the end of the day.
satori99 5y ago
Damn. Now I'm worried. Consuming less than 6 coffees a day is more unusual for me.

tomxor 5y ago

The statistic is relative: "a 53% increase" is relative to some baseline. It does not mean the absolute risk is raised to 53%. Without context these relative form are meaningless, and they are presented this way annoyingly commonly by media. For example if the baseline absolute risk is 0.0100% then the study suggests the increase would raise that to 0.0153% in absolute terms... and no I do not know what the baseline is, the headline is truly meaningless to me.

tommiegannert 5y ago
Figure 2 of the study says the ">6 cups/day" cohort had 123 of 9,265 dementia cases (1.3%). The "1-2 cups/day" reference group had 953 of 123,516 dementia cases (0.77%).
- tomxor 5y ago
  hah, so my exaggerated example was only 1 order of magnitude off.

weare138 5y ago

I agree, this contradicts several studies that concluded the opposite. Here's a couple I found after a quick search: There were no significant associations between coffee or caffeine intake and risk of cognitive impairment, overall dementia, AD, VaD, or moderate/high levels of the individual neuropathologic lesion types. https://content.iospress.com/articles/journal-of-alzheimers-disease/jad101428 https://content.iospress.com/articles/journal-of-alzheimers-... Coffee drinkers at midlife had lower risk of dementia and AD later in life compared with those drinking no or only little coffee adjusted for demographic, lifestyle and vascular factors, apolipoprotein E ε4 allele and depressive symptoms. https://content.iospress.com/articles/journal-of-alzheimers-disease/jad00920 https://content.iospress.com/articles/journal-of-alzheimers-...

unparagoned 5y ago

When people wonder how others can get stuck in their own echo chamber, remember this post. They didn't read the article, misinterpreted the stats, and just ignored the results since it didn't conform to their preconceptions.

melbourne_mat 5y ago

I think you missed the "6+ coffees a day" part.

tommiegannert 5y ago

It seems this is not the first study. The introduction says >A Mendelian randomisation study has provided evidence for a potential adverse effect of higher coffee consumption on the risk of Alzheimer’s disease, with each cup of coffee increasing the risk by 26% (13). However, observational evidence is inconsistent, and of the 11 most recent longitudinal cohort studies on habitual coffee intake and dementia risk, five supported a possible protective effect (14–18), whereas six studies found no association (19–24). ... and it looks like we have a long way to go before there's a conclusion.

vixen99 5y ago

On the other hand, caffeine is a vaso-constrictor which reduces blood supply to the brain. This is very old news and replicated many times from even 1935. What are the effects of this? To go full forward we have https://www.biorxiv.org/content/10.1101/2021.07.01.450708v1.full.pdf https://www.biorxiv.org/content/10.1101/2021.07.01.450708v1.... (July 2 2021) "Our findings unveil that conventional daily caffeine intake does not provide sufficient time to clear up psychoactive compounds and restore cerebral responses, even after 36 hours of abstinence. They also suggest investigating consequences of a paraxanthine accumulation during daily caffeine intake." As an avid coffee drinker I'd like to feel able to agree with your conclusion but I'll limit the amount wagered. https://pubmed.ncbi.nlm.nih.gov/19219847/ https://pubmed.ncbi.nlm.nih.gov/19219847/ Coffee has a lot of other components such as polyphenols which generally have a beneficial effect. May be that this counteracts the possible negative consequences of caffeine under certain conditions.