Menopausal hormone therapy, used to relieve menopausal symptoms like hot flushes and night sweats, is associated with an increased rate of dementia and Alzheimer’s disease, even though no causal relationship has been established, a new BMJ research has said.
The increase, of 24 per cent, was seen in long-term users of the therapy and also in short-term users of menopausal age of 55 years or younger, the observational research in Danish women said.
Menopausal hormone therapy, widely known as hormone replacement therapy, includes tablets containing oestrogen only, or a combination of oestrogen and progestogen, as well as skin patches, gels and creams.
Researchers from the Danish Dementia Research Centre, Copenhagen University Hospital and other Danish institutes, identified 5,589 women having dementia (cases) and 55,890 age matched dementia-free women (controls) between 2000 and 2018 from a population of all Danish women aged 50-60 years in 2000, with no history of dementia and no underlying reason preventing them from using menopausal hormone therapy.
The average age of dementia diagnosis was 70 years. Before a diagnosis, 1,782 (32 per cent) cases and 16,154 (29 per cent) controls had received the hormone therapy from an average age of 53 years.
The average duration of use was 3.8 years for cases and 3.6 years for controls.
Increased rates of dementia were found to be higher with longer use, ranging from 21 per cent for one year to 74 per cent for more than 12 years of use.
Use of progestin only therapy and vaginal oestrogen only were not associated with the development of dementia, the researchers wrote in their paper.
The researchers also said they were not able to distinguish between types of dementia developed or distinguish between tablets and other ways to take hormone therapy, such as patches.
Further, they could not rule out the possibility of women taking hormone therapy having a predisposition to both menopausal vasomotor symptoms, like hot flushes or night sweats, and dementia.
However, they said, this was a large study based on high quality treatment data with a long follow-up duration.
As such, they concluded, “Further studies are warranted to determine whether these findings represent an actual effect of menopausal hormone therapy on dementia risk, or whether they reflect an underlying predisposition in women in need of these treatments.”