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Flu vaccination linked to 40% reduced risk of Alzheimer’s disease

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Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease

#131

Post by spupe »

spandrew wrote: post #69
blagie wrote: post #36

Earlier quoted context omitted.

The scientists said it was causation. "We found that flu vaccination in older adults reduces the risk of developing Alzheimer’s disease for several years. The strength of this protective effect increased with the number of years that a person received an annual flu vaccine – in other words, the rate of developing Alzheimer’s was lowest among those who consistently received the flu vaccine every year" Yes, that's in a…

This is a mischaracterization of even the words you've quoted. The team did indeed find that flu vaccines reduced the risk of Alzheimers. But he specifically doesn't say they know why the flu vaccine lowers the risk . Ie. They can't claim causation if they don't understand the underlying reason for the change. That's not how science works. In fact in the article in question he says the opposite: That the immune syste…

> They can't claim causation if they don't understand the underlying reason for the change. That's not how science works.

Sorry but I had to nitpick here. This is exactly how science works. We first observe things that we cannot explain, and we can definitely infer causation without a complete mechanism or even a proper theory for it.

Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease

#132

Post by sweetdreamerit »

spupe wrote: post #131
spandrew wrote: post #69

Earlier quoted context omitted.

This is a mischaracterization of even the words you've quoted. The team did indeed find that flu vaccines reduced the risk of Alzheimers. But he specifically doesn't say they know why the flu vaccine lowers the risk . Ie. They can't claim causation if they don't understand the underlying reason for the change. That's not how science works. In fact in the article in question he says the opposite: That the immune syste…

> They can't claim causation if they don't understand the underlying reason for the change. That's not how science works. Sorry but I had to nitpick here. This is exactly how science works. We first observe things that we cannot explain, and we can definitely infer causation without a complete mechanism or even a proper theory for it.

It's a little more nuanced. Causation can be inferred in an experimental design. If the researchers can manipulate the independent variable (the vaccine) using an experimental and a placebo group, and then they can measure a statistically (and clinically) significant difference, then we can assume that this is not just correlation.

Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease

#133

Post by oldgradstudent »

xupybd wrote: post #45
i_love_limes wrote: post #42

Earlier quoted context omitted.

In the interview he seems to be more loose with his words, but that also doesn't say causation. In the paper the conclusion is "This study demonstrates that influenza vaccination is associated with reduced AD risk in a nationwide sample of US adults aged 65 and older." That is distinctly not causal.

Sitting down and talking it's often hard to be as precise as you would like to be. Especially when you don't have time to reflect on the implications of what you've just said.

They were very precise about causation in the interview.

They just can't include it in the paper because reviewers will make sure to remove it

Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease

#134

Post by DarkmSparks »

Jedd wrote: post #124
DarkmSparks wrote: post #117

Earlier quoted context omitted.

exactly this, because there is no treatment diagnosis is delayed as long as possible to avoid the stigma, by the time people get a diagnosis they are generally at the point they forget when to feed themselves. Prior to that the decline can be decades in the making. My gran obviously had dementia for 15 years before her diagnosis, by the time she was given it the only words she could say was "keep on keeping on"

Refer my response to parent. Specifically to your most recent point, however, I'd observe that if treatment diagnosis is delayed as long as possible to avoid the stigma, that would put back treatment diagnosis for both groups, so it's hardly a compelling distinction there. Anyway, I'd expect people with dementia at the time of their flu shot would have been assessed by the caregiver, and they would probably have been…

There is no diagnosis in the group that doesn't have dementia, there is no "after flu vaccine" in people who dont get the flu vaccine.

Its called selection bias.

The root cause of the measurement issue is that people are less likely to get the flu vaccine if they have dementia. People who had the flu vaccine are already much less likely to suffer cognitive decline even if the flu vaccine was a placebo.

This sort of stuff is why double blind RCTs exist and have millions spent on them.

Also why all the dementia treatments to date failed to work, because these issues are so often ignored.

Also perversely - mental assessments are typically carried out on people who doctors "dont" think have dementia (to rule it out as a cause of symptoms)

Consider this "back of the envelope" calculation. 10% of the population will develop dementia. having early dementia symptoms makes you 50% less likely to get the flu vaccine. 70% of people get the flu vaccine.

If you randomly selected 200 who didnt get the vaccine and 200 who did from this group, you would expect to see only 13 of the 200 develop dementia when vaccinated, but 53/200 in the unvaccinated group.

Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease

#135

Post by native_samples »

dsizzle wrote: post #118
blagie wrote: post #36

Earlier quoted context omitted.

The scientists said it was causation. "We found that flu vaccination in older adults reduces the risk of developing Alzheimer’s disease for several years. The strength of this protective effect increased with the number of years that a person received an annual flu vaccine – in other words, the rate of developing Alzheimer’s was lowest among those who consistently received the flu vaccine every year" Yes, that's in a…

This comment (and often the "correlation != causation" discussion more generally) seems to equate "causation" with "proof of causation" (in a mathematical sense), which is a flawed criteria for science IMO. The causation part (not the mere association) is the substance, so it's appropriate to use causal language. Of course any such explanation is provisional. I might think your comment is just to complain the provisi…

The quote isn't offhand, it's directly and explicitly making claims of causality, e.g. talking about the "effect" and saying the vaccination "reduces the risk".

Yes the paper says differently. So what? We're used to this from epidemiology by now. The claims they make to the government/media/public about disease frequently don't match their actual data. To discover this you have to not only read the paper but often dig through the most obscure parts of it. The fact that their claims are wrong will only emerge in, like, table 3 of Appendix 2 which is by the way only available on GitHub if at all. Here it emerges in literally the last paragraph. Then someone blogs about this and they get kicked off Twitter for spreading "misinformation".

The public's understanding of science being provisional is actually excellent and far better than the supposedly elite decision making classes. That's why the public increasingly doesn't trust claims made by scientists, and correctly so. Scientists will make bold claims of causation whilst actually having a sketchy P=0.049 regression at best and a fictional model built on circular logic at worst.

We need to hold scientists to higher standards, and especially epidemiologists. The amount of damage their sloppy "offhand" approach has caused is astronomical. Or, quicker, just accept that they aren't going to improve, have learned nothing from COVID and cut them out of society and the public conversation entirely.

Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease

#136

Post by native_samples »

lukev wrote: post #54

Lots of discussion in this thread about the accuracy of the implied claim "vaccination can prevent Alzheimers", but not a lot about the correct course of action. Which seems to me to be, unambiguously, you should absolutely be religious about getting your flu shot every year. The vaccine is known to be safe and with few side effects (or at least, safer than the actual flu, which is the bar that needs to be cleared.)…

"The vaccine is known to be safe and with few side effects"

The COVID vaccines are also "known" to be safe and with few side effects, by the sort of public health people who like to make such claims. That doesn't mean anything.

Here's the problem with flu vaccines. They do not correlate with any reduction in mortality attributed to flu. Every trial indicates effectiveness, yet despite hugely increased number of flu vaccines over the years, deaths due to flu do not move. A rational person should wonder what this implies about the reliability of vaccine trials.

Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease

#137

Post by Symmetry »

gweinberg wrote: post #84
Symmetry wrote: post #73

Earlier quoted context omitted.

I don't think that's right? In theory you could have A and B that were naturally correlated and add a causal relationship between the two that exactly canceled that correlation but that would be infinity unlikely to happen by chance. In practice the only way that A and B can be correlated is that either A causes B, B causes A, or some C causes both A and B. Interestingly if both A and B cause C the C and A as well as…

It's not by chance. If you have a heater controlled by a thermostat, it destroys the correlation that would otherwise exist between outside temperature and inside temperature. That particular example sounds silly because it is so obvious. But in economics you can find examples where you would be seeing a relationship, but it is masked by an active response to the cause, but it's not so obvious this is happening.

That's the thing though. A heater controlled by a thermostat will considerably reduce the correlation between outside and inside temperature but because it's imperfect it wont' eliminate it entirely.

Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease

#138

Post by Symmetry »

thaumasiotes wrote: post #120
Symmetry wrote: post #73

Earlier quoted context omitted.

I don't think that's right? In theory you could have A and B that were naturally correlated and add a causal relationship between the two that exactly canceled that correlation but that would be infinity unlikely to happen by chance. In practice the only way that A and B can be correlated is that either A causes B, B causes A, or some C causes both A and B. Interestingly if both A and B cause C the C and A as well as…

> In theory you could have A and B that were naturally correlated and add a causal relationship between the two that exactly canceled that correlation but that would be infinit[el]y unlikely to happen by chance. That hardly seems relevant, since we're talking about causal relationships and chance is the opposite of causation.

I have no idea what you were saying by "Causation frequently removes correlations that would otherwise exist" then.

Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease

#139

Post by ekianjo »

ksb wrote: post #71
ekianjo wrote: post #64

Earlier quoted context omitted.

This seems like a dubious recommendation. In Japan there is a large acceptance of yearly flu shots yet Alzheimer s prevalence remains high.

Perhaps not. See this article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4095986/ > Among developed countries, Japan has the lowest prevalence of both dementia in general and Alzheimer's disease in particular.

Nope, based on the same article a few lines lower:

> The burden of dementia is increasing exponentially especially in Asia-Pacific region, where more than 60% of the population reside [34]. The prevalence of dementia seems to be higher in developed countries, like Japan and Korea, than in countries with low incomes in Asia. A Japanese study found that the prevalence of dementia equals 11% among those aged more than 65 years [35, 36], whereas a Korean one found the prevalence of 6.3% [17]. Another study conducted in Korea, the Seoul study, showed that the prevalence of dementia, excluding very mild cases, was about 5.3% for overall dementia and 4.3% for AD [37].

> The prevalence of dementia greatly varies between different ethnic groups living in the same country, like in Singapore, that is probably the most multicultural region of Asia. A Singaporean study showed low standardized dementia prevalence among the ethnic Chinese (2.5% among the elderly) when compared to the ethnic Malays (4.0% among the elderly) and this finding was independent of the frequency of vascular risk factors [18]. Whereas these differences are due to different genetics or lifestyle it remains a matter of debate.

Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease

#140

Post by dsizzle »

native_samples wrote: post #135
dsizzle wrote: post #118

Earlier quoted context omitted.

This comment (and often the "correlation != causation" discussion more generally) seems to equate "causation" with "proof of causation" (in a mathematical sense), which is a flawed criteria for science IMO. The causation part (not the mere association) is the substance, so it's appropriate to use causal language. Of course any such explanation is provisional. I might think your comment is just to complain the provisi…

The quote isn't offhand, it's directly and explicitly making claims of causality, e.g. talking about the "effect" and saying the vaccination "reduces the risk". Yes the paper says differently. So what? We're used to this from epidemiology by now. The claims they make to the government/media/public about disease frequently don't match their actual data. To discover this you have to not only read the paper but often di…

You missed my point. I don't actually think the quote was offhand either (another comment suggested that possibility), but the lines from the paper I cited also uses causal language. My point is that using causal language is fine (understanding that it's provisional as all science is), and I think the scientist quote is fine.

You think the scientist quote is dishonest? It seems you too conflate causality with something like proven mathematically or 100% confidence.

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