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

It's certainly impressive that you thought up this profound and fundamental flaw in their study in just a few minutes pondering this on the couch and after briefly skimming a summary article published in a pop-media publication ... yet the fleet of scientists and researchers didn't consider this, factor it in, describe their control processes to cater for this and other confounding effects etc, for a study that spanned many years.

the online paper is here

https://content.iospress.com/articles/journal-of-alzheimers-...

They controlled by excluding patients if:

"they had a diagnosis of mild cognitive impairment (MCI), encephalopathy, or dementia of any cause during the look-back period, or if they filled a prescription for a medication indicated for AD"

Therefore they didnt exclude patients with early signs of cognitive impairment (because it is not possible to do so, because it is not recorded anywhere)

Right, so in an experiment to see who acquires AD through the decade the trial runs, they initially excluded people who may already have it. This seems a reasonable part of the method, given what they were looking for.

If your position continues to be that their numbers are skewed - and this is a HUGE correlation here - exclusively because people with dementia will forget to get a flu vaccination, then a) I think you are making unsupported claims, and b) you're arguing with the wrong person.

Perhaps throw the authors of the study a line and suggest this alternative hypothesis for the numbers they saw across their sample set of ~ 1 million people.

Thing is, like I said, it would be lovely.

But I also said, all they "proved" is that people who dont forget to get the flu vaccine are less likely to develop full blown dementia.

Just to bear that in mind if you think it brings us any closer to preventing/treating/curing dementia.