Drugs commonly given to menopausal women are not linked to an increased risk of developing dementia, according to a new study.
Hormone replacement therapy (HRT) treatments are prescribed to relieve symptoms of the menopause such as hot flushes, night sweats and mood swings.
The medication works by replacing the hormones which are lower among women during the menopausal period.
A small number of previous studies have had inconsistent findings when it comes to HRT use and dementia – while some lab studies and small trials have suggested there might be a beneficial use for the drug to stem “age related brain decline”, another study linked a certain type of hormone therapy to an increased risk of Alzheimer’s.
The team of researchers, from the universities of Nottingham, Oxford and Southampton, set out to conduct a large trial involving more than 118,000 women aged 55 and over who were diagnosed with dementia between 1998 and 2020.
Their information, drawn from UK GP surgery data, was compared to almost half a million women who did not have dementia.
In each of the groups, 14% of women used HRT for more than three years.
Overall, no increased risks of developing dementia associated with menopausal hormone therapy were seen, the authors said.
But there were different findings among some sub-groups within the study.
Long term users of a specific treatment were found to have a “slightly” increased risk of developing Alzheimer’s, according to the study, published in the BMJ.
But taking oestrogen-only therapy was linked to 15% decreased odds of dementia overall among women younger than 80 who received treatment for at least 10 years, with a 1.1% decrease in risk for each year of treatment.
“This large observational study found no overall association between use of menopausal hormone therapy and risk of developing dementia,” the authors concluded.
“This finding was consistent across different types of hormones, doses, applications, and time of hormone therapy initiation.
“We found a decreased risk dementia for cases and controls younger than 80 years at diagnosis who had been taking oestrogen-only therapy for 10 years or more.
“A subgroup analysis of cases with a diagnosis of Alzheimer’s disease showed a small increase in risk associated with oestrogen-progestogen therapy. This rose with each year of exposure, reaching average risk increase of 11% for between five and nine years of use and 19% for 10 years or more.”
In a linked opinion piece, Professor Pauline Maki, from the University of Illinois, and Professor JoAnn Manson, from Harvard Medical School, said the study should provide “reassurance” for women prescribed the drug for “vasomotor symptoms” – namely hot flushes and night sweats.
“An improved understanding of the risks and benefits of hormone therapy is needed to promote evidence based management of menopausal symptoms in women,” they wrote.
“Overall, these observations do not change the recommendation that menopausal hormone therapy should not be used to prevent dementia. At the same time, it is helpful for providers to put
dementia findings in context for patients.
“The primary indication for hormone therapy continues to be the treatment of vasomotor symptoms, and the current study should provide reassurance for women and their providers when treatment is prescribed for that reason.”
