As a long term user, I have had leg weariness etc. I have read the research and link with altzhiemers being inconclusive, and no link has ever mentioned the fact that PPI's reduce the uptake of Vitamin B12. which has an important effect on the brain function.
So I stopped taking a PPI, and increased my Vit. B12 intake. The effect was amazing, I am like a new person, fit as a fiddle, can walk much further, thinking is better. I am 81.