Credit: Original article published here.
A recent study conducted by researchers at Mass General Brigham found that women are more likely to develop Alzheimer’s disease (AD) than men, with two-thirds of the AD population being female.
The study design was cross-sectional in nature and focused on the relationship between the risk of AD, sex, age of onset of menopause, and hormone therapy (HT). The results, published in JAMA Neurology, suggested that early age at menopause may be a risk factor for AD as well as dementia.
Rachel Buckley, PhD, from the Department of Neurology at Massachusetts General Hospital (MGH) and senior author of the study commented, “HT is the most reliable way to ameliorate severe menopause symptoms, but over the last few decades, there has been a lack of clarity on how HT affects the brain.”
Dr. Buckley and coresearchers analyzed participants enrolled in the Wisconsin Registry for Alzheimer Prevention who underwent 18F-MK-6240 and 11C-Pittsburgh compound B positron emission tomography (PET) scans. Then the researchers evaluated the relationship between menopause and HT use and regional tau PET in seven regions of the brain that show sex differences across temporal, parietal, and occipital lobes. The primary exposures included premature menopause, early menopause, and regular menopause, as well as HT user (current/past use) and HT nonuser (no current/past use).
“We found that the highest levels of tau, a protein involved in AD, were only observed in hormone therapy users who reported a long delay between age at menopause onset and their initiation of hormone therapy,” Dr. Buckley said. “The idea that tau deposition may underlie the association between late hormone therapy intervention and AD dementia was a huge finding, something that hadn’t been seen before.”
The study found that in cognitively unimpaired individuals, female sex, earlier age at menopause, and HT use were associated with higher regional tau PET in individuals with elevated Aβ, compared with male sex, later age at menopause, and no HT use. The affected regions included medial and lateral regions of the temporal and occipital lobes. Late initiation of HT (>5 years following age at menopause) was associated with higher tau PET compared with early initiation.
“Hormone therapy can have negative effects on cognition, but only if initiated several years after age at menopause. These observational findings support clinical guidelines that state hormone therapy should be administered close to menopause onset, but not several years after,” first author Gillian Coughlan, PhD, remarked.
