Out of total published studies included in meta-analysis of CSF tau levels in DOC 5 published studies were of vascular dementia (VaD) [7, 18, 22–24], 2 of Parkinson's disease-associated dementia (PDD) [15, 20], 1 of mixed dementia [16], and the rest were non-AD dementia (non-ADD) [17, 19]. This evidence concerns the gene MAPT and vascular dementia.