I would go further. In my medical research work I saw dozens, probably hundreds of "statistically significant" correlations between different variables in a rather small dataset. I found them just by taking different subsets or summarizing the same data in a few different ways.
I didn't find any interesting and so published nothing about them, but I am sure others could build entire careers out of coming up with narratives to explain those correlations.
I have to think that people who have trouble finding correlations are either clueless about exploring the data (eg have only ever looked at dynamite plots of their results) or are measuring something so swamped by instrumental noise it is meaningless.
Bredesen DE. Reversal of cognitive decline in Alzheimer's disease. Aging (Albany NY). 2016 Jun;8(6):1250-8. doi: 10.18632/aging.100981.
Bredesen DE. Reversal of cognitive decline: A novel therapeutic program. Aging (Albany NY). 2014; 6:707-17. doi: 10.18632/aging.100690.
The number of patients studied is too few, i.e. is grossly underpowered statistically, and the results do not allow any general conclusion to be drawn.
https://www.sciencebasedmedicine.org/mend-protocol-for-alzhe...
The commercialization of the MEND protocol might have run into some partnership issues between the original researcher and the first company he worked with dispensing the treatment:
http://www.prnewswire.com/news-releases/dr-dale-bredesen-ann...
Here is a more layman-friendly description of the MEND protocol.
My intuition is that it is more likely caused by an infection than that it is just a malfunction caused by random chance
If it is caused by a specific infection, then one would expect such a specific infection to cause the disease in young as well as older people.
Neither of these scenarios are known to occur.
If you extend beyond these simple scenarios, then you have to assume that there is another (unknown) factor that induces Alzheimer's disease, and therefore that the theory of infectious disease causing this condition is not sufficient.
Hence statements like "We can't keep ignoring the evidence", "landmark editorial", etc.
Or to taxpayers when some pharmaceutical company finds a specious statistical correlation between Alzheimer's and an infectious agent that one of their products happens to treat.
A cynical view, yes. Borne out of my reading of Bad Pharma and coming across at least one startup whose business model was to do this with genetic tests.
Experimental science, however, demands that one establishes a cause and effect relationship. There is no known cure of Alzheimer's disease, so one cannot refer to experimental medicine for an answer, with the exception of inherited dominant genetic mutations that impact only a small number of people. Unfortunately, of these mutations, those affecting the APP gene do not cause neuronal loss in mice; so the mouse models are inherently problematic.
This editorial calls for a clinical trial for antimicrobials in this disease. While I doubt that Alzheimer's is caused by infectious agents, there really is no harm in trying (except perhaps to the pockets of the trial's sponsors). In fact a trial of the antibiotic minocycline was completed in 2014 [1], however the results do not appear to have been reported.
[1] https://clinicaltrials.gov/ct2/show/NCT01463384