Additionally, in an observational study examining 6-month change in plasma AD biomarkers in women before and after treatment with MHT (n = 193) in comparison to non-treated controls (n = 31), there were no overall differences in biomarkers between control and MHT groups, but group differences emerged when considering APOE4 genotype (Depypere et al., 2023). This evidence concerns the gene APOE and Alzheimer disease.