Direct consideration of composite Aβ-PET z-scores as a covariate in a TSPO-PET subanalysis of AD patients revealed a consistent sex effect between females and males (i.e., TSPO-PET z-scores in the frontal cortex: 1.28 ± 0.17 vs. 0.58 ± 0.21, p = 0.010). This evidence concerns the gene TSPO and Alzheimer disease.