medwireNews: Women who receive combination menopausal hormone therapy may be more likely to develop dementia than other women, even if the treatment is taken for a short time around the age of 55 years or younger, researchers have found.
They add that more evidence is needed to establish whether the link is causal or if women receiving the therapy are predisposed to developing dementia.
Between 2000 and 2018, the group analyzed medical records in Danish national registries regarding women aged 50–60 years in 2000 who had no history of dementia or contraindications for use of menopausal hormone therapy.
In all, there were 5589 incident cases of dementia and these individuals were aged a median of 70 years at diagnosis, with 26.1% registered as having Alzheimer’s disease and 79.4% as having late-onset dementia. These women were matched for age with 55,890 women who did not develop the condition.
Menopausal hormone therapy, consisting of continuous or cyclic estrogen and progestin, was taken by 1782 (31.9%) women with dementia and 16,154 (28.9%) without the condition prior to diagnosis, at a median age of 53 years and for a median duration of 3.8 years and 3.6 years, respectively.
Nelsan Pourhadi (Copenhagen University Hospital, Denmark) and colleagues report that the risk for all-cause dementia was increased by a significant 24% among women who were taking combined menopausal therapy, compared with those who were not. And the risk increased in line with duration of use, ranging from a 21% increased risk with less than 1 year of use to a 74% increased risk with more than 12 years of use.
The researchers note that the increased dementia risk associated with menopausal therapy was evident for women with late-onset dementia and those with Alzheimer’s disease, with significant risk increases of 21% and 22%, respectively.
There was also a significant 24% increased risk for dementia among women who had received and stopped taking menopausal therapy by the age of 55 years, they comment.
According to the authors, the increased risk for dementia was similar between continuous (daily) and cyclic (daily for 10–14 days per month) treatment regimens.
They also note that there was no increased risk for dementia with the use of progestin only and vaginal estrogen only therapies.
In a related editorial, Kejal Kantarci (Mayo Clinic Rochester, Minnesota, USA) and JoAnn Manson (Harvard Medical School, Boston, Massachusetts, USA) commented: “Although Pourhadi and colleagues’ study was done carefully using national registries, the observed associations could be artefactual and should not be used to infer a causal relationship between hormone therapy and dementia risk. These findings cannot inform shared decision making about use of hormone therapy for menopausal symptoms.”
They add: “Randomised clinical trials provide the strongest evidence on the effect of hormone therapy on dementia risk. Furthermore, brain imaging biomarkers might help to identify the effects of hormone treatment on dementia pathophysiology at an earlier stage, making assessment of its influence on dementia risk in trials of recently postmenopausal women feasible.”
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2023 Springer Healthcare Ltd, part of the Springer Nature Group