TSPO and Alzheimer disease: BMI and the Aβ-plaque-independent microglial response were significantly associated in females with AD (r = 0.44, p = 0.02) but not in males with AD (r = − 0.19, p = 0.44) after adjustment for TSPO gene SNP and there was a significant BMI x sex interaction (T = 3.08, p < 0.01; Fig. 4A), when controlled for TSPO gene SNP and AD signature CSF markers.