A decrease in estrogen during menopause may affect cognitive function
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Commencing hormone replacement therapy (HRT) within five years of the onset of postmenopause appears to decrease the likelihood of developing Alzheimer’s disease. In contrast, starting HRT later in life may have adverse effects, indicating that the timing of the therapy is crucial for its impact on the brain.
Women face a greater risk of developing Alzheimer’s, particularly after menopause, compared to men. This heightened risk may be linked to reduced estrogen levels, which play vital roles in brain energy regulation and inflammation. Consequently, HRT has surfaced as a potential method to reduce Alzheimer’s risk following menopause. However, research on its effectiveness has produced mixed outcomes.
To investigate this, Fnu Vaibhav Pandit Bagwat Deira Sharma from Health Science University in India and his team analyzed 53 studies encompassing over 8.4 million postmenopausal participants regarding Alzheimer’s disease prevalence.
In a randomized controlled trial, participants receiving HRT exhibited, on average, a 38% greater risk of developing Alzheimer’s compared to those not on HRT. Conversely, observational studies suggested a 22% reduction in Alzheimer’s risk among HRT users.
Vaibhav presented these findings at a meeting with the American Nerve Association in Maryland on September 15th, noting that the disparity is likely age-related. Most subjects in the randomized trial were over 65, while those in observational studies tended to be younger. Further analysis revealed that individuals who initiated HRT within five years post-menopause had a decreased risk of Alzheimer’s by 32% over a follow-up period ranging from five years to others that consumed their lifetime.
“This transition during menopause represents a neurological shift,” stated Roberta Brinton from the University of Arizona, who was not part of the research. As estrogen levels decline, the brain seeks alternative energy sources. There is some evidence suggesting that this reallocation may utilize compounds meant for brain function while sacrificing others, leading to potential neurodegeneration. She posits that HRT may either initiate or halt this transition during menopause. However, if the brain has already undergone this shift, HRT may be ineffective.
“More research is essential to clarify this perplexity,” remarked Vaibhav. Without a clearer comprehension of HRT’s impact, he warns that “women may miss out on advantages, and some may inadvertently face harm.”
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Source: www.newscientist.com
