Yet, MR‐Egger regression indicated that some results were affected by horizontal pleiotropy, including HMG CoA reductase inhibitors versus dementia due to Parkinson's disease, glucocorticoids versus dementia due to Parkinson's disease, drugs affecting bone structure and mineralization versus FTD, and antimigraine preparations versus vascular dementia (all p < 0.05, Table 4). This evidence concerns the gene HMGCR and frontotemporal dementia.