Fig. 2

Effects of circulating phytosterols levels on the risk of Alzheimer’s disease and Parkinson’s disease. Using two different summary-level data on AD, genetically predicted circulating levels of stigmasterol and sitosterol were associated with a decreased risk of AD (A). There was no effect of phytosterols levels on the risk of PD and age at onset of PD (B). Alzheimer’s disease; PD, Parkinson’s disease; PD OAA, PD age at onset; UKB, UK Biobank; SNP, single nucleotide polymorphism; OR, odds ratio; IGAP, International Genomics of Alzheimer’s Project; IVs, instrumental variables; N, number