Could also just be confounding effects. Espresso machines tend to be expensive, as are cafés where people go to drink espresso. Did the study control for income?
That varies greatly depending on where you are in the world. In most of southern europe "a coffee" is an espresso, and outside of urban and/or tourist centers the normal price is less than 1€.
The study was done in Verona, where I suspect that espresso consumption isn't highly correlated with economic status.
I’m genuinely curious about the economics of the southern European coffee shop. The machines are quite expensive $20,000-$30,000+ (+- $5,000 - $10,000) and so for just 1€ plus they have to eat, potentially pay employees, etc. how viable are these shops?
On the other hand I think that the fact that such cafes exist and seem to work well speaks to walkability and proper transit as a cornerstone of entrepreneurship. In America you basically have to start a Starbucks drive through to get enough volume, or you have to charge $2.65 or something for a single because of a lack of volume.
Proper density (not Manhattan, moreso Amsterdam) and walkability seem to me to drive economic growth and encourage new businesses that don’t need to raise rounds of funding.
That would assume there is a correlation between Alzheimer's and income. In some quick googling of studies, there appears to be. However, with often differing results from US vs. European studies (and studying different things like education instead of income and vice versa, dementia vs. Alzheimers and vice versa, urban vs. macro and vice versa), there are hints that it is an accessibility of diagnosis issue.
We still don't know enough about Alzheimer's to have a definitive bullet list of healthy habits to stave it off. Sleep, exercise, dental health, all have some weak evidence behind it. It seems that Alzheimer's is still a more equal opportunity destroyer than heart disease or many cancers where there are plenty of evidence that you can mitigate risks with lifestyle changes.