Although experts stressed the need for further research, the findings support current clinical guidelines that prescribe hormone therapy based on its benefits and other risks, and not for dementia prevention purposes.
Hormone therapy, also known as hormone replacement therapy, aims to compensate for the natural decline in hormones during menopause, helping to alleviate symptoms such as hot flashes, mood swings, sleep disturbances, and night sweats.
The treatment is available in various forms including tablets, gels, sprays and creams, and may contain estrogen, progesterone or testosterone hormones.
A research team from the UK, Ireland, Switzerland, Australia and China conducted a comprehensive review of ten studies involving more than one million women to investigate whether the use of hormone therapy affects the risk of developing mild cognitive impairment or dementia in women before and after menopause.
The study included patients with mild cognitive impairment, and women with early menopause or premature ovarian insufficiency (where the ovaries stop functioning before the age of forty).
The analysis, published in The Lancet Healthy Longevity, concluded that there was no "significant association" between hormone therapy and the risk of cognitive impairment or dementia, and that factors such as timing, duration, or type of treatment did not show significant effects.
The researchers stressed that prescriptions should be based on other perceived benefits and risks, not on dementia prevention, and called for high-quality studies to analyze the relationship more accurately, especially for women with early menopause or mild cognitive impairment.
“Dementia disproportionately affects women globally, making it crucial to understand the contributing factors and find ways to reduce the risk,” said Melissa Melville, the study’s lead researcher. She added, “The impact of hormone therapy on memory, cognition, and dementia risk remains one of the most debated issues in women’s health, with conflicting research and concerns leaving women and healthcare professionals perplexed.”
For her part, Professor Amy Spector pointed out that the World Health Organization does not currently provide specific guidance on hormone therapy and cognitive outcomes, expressing her hope that the review will contribute to the development of new guidelines expected in 2026.
Spector noted that "hormone therapy does not appear to affect the risk of dementia negatively or positively, but we need more long-term research to fully understand its effects."
Menopause specialist Louise Newson offered a different perspective, arguing that "it is impossible to definitively say that hormone therapy does not affect the risk of dementia," noting that hormones play vital roles in brain function.
Newson explained that modern hormone therapy uses hormones that are chemically identical to natural ones, providing benefits that outweigh the risks, including improving symptoms such as memory problems and preventing osteoporosis and heart disease.
