Hormone replacement therapy could reduce the risk of Alzheimer’s disease in women, according to the University of East Anglia.
A new study has shown that hormone replacement therapy is associated with better memory, cognition and larger brain volumes in later life among women who carry the APOE4 gene, the strongest risk factor gene for Alzheimer’s.
The researchers found that hormone replacement therapy is most effective if it is introduced early in the menopause during perimenopause.
The APOE4 genetic risk is stronger in women
“We know that 25% of women in the UK are carriers of the APOE4 gene and that almost two-thirds of Alzheimer’s patients are women,” said Professor Anne-Marie Minihane from UEA’s Norwich Medical School and director of the Norwich Institute for Healthy Aging at UEA.
“In addition to living longer, the reason behind the higher female prevalence is thought to be related to the effects of menopause and the impact of the APOE4 genetic risk factor being greater in women. We wanted to find out whether HRT could prevent cognitive decline in at-risk APOE4 carriers.”
The researchers analysed data from 1,178 women who participated in the European Prevention of Alzheimer’s Dementia initiative, which was created to study participants’ brain health over time.
The initiative includes data from ten countries and tracks participants’ brains from ‘healthy’ to a diagnosis of dementia or Alzheimer’s. Participants had to be over 50 years old and dementia-free to be included in the study.
Early use of hormone replacement therapy has benefits
“We found that hormone replacement therapy use is associated with better memory and larger brain volumes among at-risk APOE4 gene carriers. The associations were particularly evident when hormone replacement therapy was introduced early, during the transition to menopause, known as perimenopause,” explained Dr Rasha Saleh, also from UEA’s Norwich Medical School.
“This is really important because there have been very limited drug options for Alzheimer’s disease for 20 years and there is an urgent need for new treatments. The effects of hormone replacement therapy in this observation study, if confirmed in an intervention trial, would equate to a brain age that is several years younger,” continued Dr Saleh.
The researchers examined associations with cognition and brain volumes using MRI scans. They did not focus on dementia cases, but instead on cognitive performance and lower brain volumes, which can be used to predict the risk of dementia.
The researchers have said that it may be too early to say for certain if hormone replacement therapy can reduce dementia risk in women. However, the results of this study highlight the potential importance of hormone replacement therapy and the role personalised medicine can play in reducing the risk of Alzheimer’s.
“The next stage of this research will be to carry out an intervention trial to confirm the impact of starting HRT early on cognition and brain health. It will also be important to analyse which types of HRT are most beneficial,” said Professor Minihane
“This important finding from the EPAD Cohort highlights the need to challenge many assumptions about early Alzheimer’s disease and its treatment, especially when considering women’s brain health. An effect on both cognition and brain changes on MRI supports the notion that HRT has tangible benefit. These initial findings need replication however in other populations,” concluded Professor Craig Ritchie, from the University of Edinburgh.
