A team of researchers from the University of East Anglia (UEA) and the University of Edinburgh have found evidence of the potential importance of hormone replacement therapy (HRT) in reducing the risk of Alzheimers disease in women carrying the APOE4 gene. The study was published in the Alzheimers Research Therapy journal. Dementia is one of the worlds biggest health threats. Almost two in three people with Alzheimers are female, and about a quarter of women in the UK alone carry a gene called APOE4, which is the strongest risk factor gene for the disease.The number of people living with the condition worldwide is set to nearly triple to 153 million by 2050, and experts have warned it presents a major and rapidly growing threat to future health and social care systems in every community, country and continent.HRT, which helps control symptoms of the menopause, is associated with better memory, cognitive function and larger brain volumes in later life in women with the APOE4 gene, the researchers found. Although the paper stressed they could not say for sure that HRT cut the risk in women, the findings were really important amid limited drug options for dementia and an urgent need for novel treatments. Its too early to say for sure that HRT reduces dementia risk in women, but our results highlight the potential importance of HRT and personalised medicine in reducing Alzheimers risk. 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 Prof Michael Hornberger, of UEAs Norwich Medical School.The team analysed data from 1,178 women taking part in the European Prevention of Alzheimers Dementia initiative, which was set up to study participants brain health over time.The project, which involves 10 countries, tracked the brains of 1,906 people over 50 who did not have dementia at the start of the study. For the new research, experts looked at the results of cognitive tests and brain volumes as recorded by MRI scans.The results showed that APOE4 carriers who also used HRT had better cognition and higher brain volumes than people not on HRT and non-APOE4 carriers. Dr Rasha Saleh, of Norwich Medical School, said, This is really important because there have been very limited drug options for Alzheimers disease for 20 years and there is an urgent need for new treatments. The effects of HRT in this observation study, if confirmed in an intervention trial, would equate to a brain age that is several years younger.