No Dementia Risk with Hormone Replacement Therapy
A large UK study found that use of menopausal hormone therapy (MHT, also known as hormone replacement therapy, HRT) is not associated with increased dementia risk.
The study, published in the BMJ, found within the subgroup of women with a specific diagnosis for Alzheimer’s disease, a slight increasing risk association was found with use of oestrogen-progestogen treatments, but only seen for long-term usage (5 years or more).
This study “brings clarity to previously inconsistent findings and should reassure women in need of menopausal hormonal therapy,” said the researchers.
MHT relieves menopausal symptoms such as hot flushes, sleep disturbance, mood swings, memory losses and depression. Treatment includes oral tablets with oestrogen only, or oestrogen and progestogen combined, as well as patches, gels and creams.
Early signs of dementia are similar to some menopausal symptoms. Research has shown a beneficial link between oestrogen and age-related brain decline. However, in the largest trial of MHT, the Women’s Health Initiative Memory Study, an increased dementia risk was found among users of oestrogen-progestogen treatments. A recent study picked up a possible link to Alzheimer’s disease among users of both oestrogen-only and oestrogen-progestogen treatments, though the study has some issues.
To address this uncertainty, researchers set out to investigate the risks of developing dementia for women using commonly available menopausal hormone therapy treatments.
They used two UK primary care databases to analyse MHT prescriptions for the 118 501 women aged 55 and older diagnosed with dementia between 1998 and 2020 (cases), and 497 416 matched women without dementia (controls).
After adjusting for confounding factors, no overall associations were found between use of hormone therapy and risk of dementia, regardless of hormone type, application, dose, or duration of treatment. Only a slightly decreased risk of dementia was found in one subgroup: those under 80 years who had been taking oestrogen-only therapy for 10 years or more.
Analysis of cases with a specific diagnosis of Alzheimer’s disease showed a slight increase in risk associated with oestrogen-progestogen therapy. This rose gradually with each year of exposure, reaching an average 11% increased risk for use of between 5 and 9 years and an average 19% for use of 10 years or more, equivalent to, respectively, five and seven extra cases per 10 000 woman years.
As this is an observational study it cannot establish cause, and some limitations include incomplete recording of menopausal symptoms, particularly for women registered after their menopause. However, its large size counts in its favour.
According to the researchers, this study provides the most detailed estimates of risk for individual treatments, and their results are in line with existing concerns in guidelines about long term exposures to combined hormone therapy treatments.
“The findings will be helpful to policy makers, doctors, and patients when making choices about hormone therapy,” they concluded.
The findings do not change the recommendation that menopausal hormone therapy should not be used to prevent dementia, US researchers commented in a linked opinion article. However, it is helpful for providers to put dementia findings in context for patients, they added.
“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,” they concluded.
Source: News-Medical.Net
