Hormone replacement therapy may increase risk of dementia and Alzheimer's, a Danish study suggests

Hormone replacement therapy (HRT) can raise the risk of dementia and Alzheimer’s, a Danish study has suggested.

Those taking tablets were more likely to be diagnosed with the illnesses according to data involving over 60,000 women, but some are “dismissive” of the findings.

Experts from the University of Copenhagen and the Danish Dementia Research Centre stressed the study was “merely observational”.

The data suggested that the chances of developing the diseases increased the longer women were taking the medication – which is used to treat menopause symptoms including hot flushes, night sweats, mood swings and reduced sex drive.

Researchers looked at use of combined oestrogen and progestin (synthetic progestogen) therapy and the development of dementia according to type of hormone treatment, duration of use, and age of the user.

The study identified 5,589 cases of dementia, at an average age of 70, alongside a comparison of a further 55,890 women of the same age, who were dementia-free between 2000 and 2018.

The research 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.”

Experts into research of the diseases said while there were strengths to the study – including its large size, good data and varied treatments – observational studies such as this cannot replace clinical trials.

Dr Susan Kohlhaas, of Alzheimer’s Research UK, said that findings into the link between HRT and dementia have been “inconclusive and contradictory”.

She said: “This large, nationwide Danish study has found an association between both short and long-term use of HRT and an increased risk of dementia.

“Unfortunately, it doesn’t provide a conclusive answer on whether HRT contributes to dementia risk, because the study did not consider some of the other factors known to be involved, such as social isolation, smoking or dietary factors like alcohol.

“Women need to understand the implications of deciding to take HRT in terms of benefits and risks and, at the moment, as far as dementia is concerned, we’ll need to wait for more research to give clearer answers.

“In the meantime, people should speak to a qualified healthcare professional if they would like to know more about the known benefits and risks of taking HRT to manage symptoms of the menopause.”