Increased Alzheimer's risk during the menopause transition: A 3-year longitudinal brain imaging study

Two thirds of all persons with late-onset Alzheimer's disease (AD) are women. Identification of sex-based molecular mechanisms underpinning the female-based prevalence of AD would advance development of therapeutic targets during the prodromal AD phase when prevention or delay in progression is most likely to be effective. This 3-year brain imaging study examines the impact of the menopausal transition on Alzheimer's disease (AD) biomarker changes [brain beta-amyloid load via C-11-PiB PET, and neurodegeneration via F-18-FDG PET and structural MRI] and cognitive performance in midlife. Fifty-nine 40-60 year old cognitively normal participants with clinical, neuropsychological, and brain imaging exams at least 2 years apart were examined. These included 41 women [15 premenopausal controls (PRE), 14 perimenopausal (PERI), and 12 postmenopausal women (MENO)] and 18 men. We used targeted minimum loss-based estimation to evaluate AD biomarker and cognitive changes. Older age was associated with baseline A beta and neurodegeneration markers, but not with rates of change in these biomarkers. APOE4 status influenced change in A beta load, but not neurodegenerative changes. Longitudinally, MENO and PERI groups showed declines in estrogen-dependent memory tests as compared to men (p<.04). Adjusting for age, APOE4 status, and vascular risk confounds, the MENO and PERI groups exhibited higher rates of CMRgIc decline as compared to males (p <=.015). The MENO group exhibited the highest rate of hippocampal volume loss (p's <=.001), and higher rates of A beta deposition than males (p<.01). CMRgIc decline exceeded AP and atrophy changes in all female groups vs. men. These findings indicate emergence and progression of a female specific hypometabolic AD-endophenotype during the menopausal transition. These findings suggest that the optimal window of opportunity for therapeutic intervention to prevent or delay progression of AD endophenotype in women is early in the endocrine aging process.