Postmenopausal Brains Show 20% Drop in Glucose Metabolism and White Matter Volume in Brinton 2021 MRI Cohort

The menopausal transition therefore functions as a critical window during which preexisting neurological reserve is tested; women entering menopause before age 45 face amplified risk trajectories that hormone-replacement timing studies suggest can be partially mitigated if initiated near the final menstrual period. Future work must incorporate APOE genotype, sleep architecture, and vascular metrics to determine whether the observed energy deficit is causal or epiphenomenal to later neurodegeneration.