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
#2Summary: there were hints from smaller studies or studies on particular groups (e.g. veterans) that flu vaccinations can reduce the probability of elderly people to develop Alzheimer's dementia. Here, almost 1 million pairs of recently flu vaccinated and not vaccinated people were matched and studied. A large protective effect was found. Other adulthood vaccinations show similar effects, hinting at a more general mechanism. There is a section about hypothesized mechanisms in the paper [0] which also points towards more general effects and not simply "avoidance of infection".
Search [0] for "Hypothesized mechanism" or even "BCG" for a concrete example of a vaccine that most likely does not act via prevention of infection (it is a tuberculosis vaccine and most people never get tuberculosis. It still shows a protective effect).
[0] https://content.iospress.com/articles/journal-of-alzheimers-... (Open Access)
Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease
#3Great news !
It’s good to know that flu vaccination has two benefits
Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease
#4That's an incredible effect size.
Mechanisms hypothesized to be at play:
"These mechanisms—and those underlying the effects of adulthood vaccinations on all-cause dementia risk in general—can be grouped into at least three broad, non-exclusive categories: 1) influenza-specific mechanisms, including mitigation of damage secondary to influenza infection and/or epitopic similarity between influenza proteins and AD pathology; 2) non–influenza-specific training of the innate immune system; and 3) non–influenza-specific changes in adaptive immunity via lymphocyte-mediated cross-reactivity."
Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease
#5Never gotten the flu vaccine before. Biggest fear in life is alzheimers. Guess I will get the flu vaccine annually going forward.
Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease
#6People who get yearly flu vaccines probably go to the doctor more regularly than those who do not. I would expect that people who more regularly go to the doctor are also more concerned about their health. I'd expect people who are concerned with their health to behave in ways that limit disease.
Without a proposed method of action, I suspect this is just noise.
Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease
#7This article has very few details and is rather questionable, at best. Correlation does not imply causation. It could very well be that people who choose to get flu vaccines are more health-conscious and live a healthier lifestyle so they are less likely to get Alzheimers.
Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease
#8Great news ! It’s good to know that flu vaccination has two benefits
Correlation is not causation. Ice cream sales don’t cause drowning.
Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease
#9My sister who is a public health specialist, cautioned me about how difficult establishing cause-and-effect in these sorts of discussions can be in general. She hasn't talked to me about this specific case, but lemme bring something up from the perspective that we Computer Scientists can understand.
Cause-and-effect chains form a DAG (Directed Acyclic Graph). For example, A causes B causes C, in theory (or in this case, A causes B prevents C. Cause vs prevent doesn't really matter, its just a negative on the correlation diagrams)
In this case, we want to determine if "Flu Vaccination causes/prevents Alzheimer's Disease".
Now lets consider a bunch of real life factors. Wealth, Age, Sex, Race, Educational Attainment, Insurance. Just the basic stuff anyone would think about. Lets focus on Educational Attainment + Insurance to keep things simple.
* Education -> Flu + Education -> Alzheimer's? Or is it the case that "stronger mind -> Education -> Flu Vaccines" and "stronger mind -> Education -> Alzheimer's" ?? Education is almost certainly a conflating situation (Education would probably cause higher flu vaccine uptake, and simultaneously would reduce Alzheimers), so maybe the Flu vaccine isn't causing the effect... but is instead just a cross-correlation to education level.
* Insurance probably causes flu-vaccines (because flu vaccines are free for most insurance plans). Insurance probably doesn't cause/prevent Alzheimer's though. So we have "Insurance -> Flu-vaccine -> Alzheimer", which means we don't have to worry about a cross-correlation in this case.
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Etc. etc.
Basically: to truly understand if we have a cause-and-effect situation here, we need to think of all possible conflating factors (such as education), while discounting factors that are "along" the DAG-chain towards the hypothetical result (ex: Insurance).
After that, there's apparently a lot of math and analysis that we can do. If we take the records of the people who participated in this study, and get their educational levels + insurance information, we can then account for these conflating factors.
I probably messed up the language and everything else for that matter. But just a reminder that public health discussions are rather technical. There's both a science and an art to the whole process, and just reading the "results in the raw" could lead to a misunderstanding.
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The best example of this is "Ice Cream causes Drowning". (Real life: Hot summer temperatures cause ice-cream consumption. Hot summer temperatures cause people to swim.) We need to account for the Hot-temperature effect if we want to find the truth behind that correlation.
There's also the chance that we've got it all backwards. Alzheimer's causes people to stop taking the flu vaccine. (IE: Alzheimer's might cause people to be more easily swayed by anti-vax propaganda, causing them to take less flu vaccines)
Figuring out all possibilities (as well as possibilities that aren't even listed) is the job of a public health care specialist. They'll get it wrong, but hopefully less wrong than you or I would. There's apparently mathematical techniques to be used to tackle each of these questions I brought up.
Re: Flu vaccination linked to 40% reduced risk of Alzheimer’s disease
#10People who get yearly flu vaccines probably go to the doctor more regularly than those who do not. I would expect that people who more regularly go to the doctor are also more concerned about their health. I'd expect people who are concerned with their health to behave in ways that limit disease. Without a proposed method of action, I suspect this is just noise.
The researchers controlled for "number of routine well visits during the look-back period, and total number of health care encounters during the look-back period (as a proxy for overall healthcare utilization rate)" [1].
[1] https://content.iospress.com/articles/journal-of-alzheimers-...