It seems this is not the first study. The introduction says >A Mendelian randomisation study has provided evidence for a potential adverse effect of higher cof

It seems this is not the first study. The introduction says >A Mendelian randomisation study has provided evidence for a potential adverse effect of higher coffee consumption on the risk of Alzheimer’s disease, with each cup of coffee increasing the risk by 26% (13). However, observational evidence is inconsistent, and of the 11 most recent longitudinal cohort studies on habitual coffee intake and dementia risk, five supported a possible protective effect (14–18), whereas six studies found no association (19–24). ... and it looks like we have a long way to go before there's a conclusion.