GFAP as dementia biomarker isn't a new discovery. Here's a 2023 meta-analysis that used papers as old as 2020.
The article (University press release) does mention this... but seeing a known suspect in the biomarker list would lend some confidence to any novel biomarkers found. So, it's good to see multiple studies having similar hits.
One starting point for reading: https://academic.oup.com/clinchem/article/59/1/202/5622131
> Proteins (for example Glial Fibrillary acidic protein, GFAP) had previously been identified as potential biomarkers for dementia in smaller studies, but this new research was much larger and conducted over several years.