Long-term postmenopausal hormone therapy might increase the risk of Alzheimer’s disease

A newly published Finnish study compares the postmenopausal hormone therapy use of women diagnosed with Alzheimer’s and their healthy controls.

According to a study published in BMJ journal, postmenopausal hormone therapy is linked to increased risk of Alzheimer’s disease.

Researchers from University, Helsinki University Hospital, and Folkhälsan Research Centre compared the hormone therapy use of 85 000 postmenopausal women, who had received a diagnosis of Alzheimer’s disease, to control women of the same age without diagnosis.

According to the results, systemic postmenopausal hormone therapy use increased the risk of Alzheimer’s disease by 9 to 17 per cent.

The increased risk was especially associated with hormone therapy exposure of over 10 years, and the risk did not differ significantly between users of estradiol and oestrogen-progestogen combination. However, the use of vaginal estradiol only showed no such risk.

– We were surprised by these results as in our previous studies we have demonstrated that postmenopausal hormone therapy decreases the risk of cardiovascular diseases, and also potentially the risk of vascular dementia. The mechanisms of Alzheimer’s disease differ, however, from those of vascular diseases, says researcher Tomi Mikkola from University of Helsinki and Helsinki University Women’s Hospital.

Previous data on the association between use of postmenopausal hormone therapy and risk of Alzheimer’s disease is conflicting. 

Alzheimer’s disease occurs more frequently in women than in men, which might be due to the longer life expectancy of women. Several animal studies have shown that oestrogens can be neuroprotective, and therefore it has been thought that prolonging the oestrogen supply with postmenopausal hormone therapy could protect against Alzheimer’s disease.

– Hormone therapy has indisputable benefits when used to treat the symptoms of menopause, like hot flashes and sleeping disorders. However, hormone therapy should not be used to prevent cognitive decline and dementia, as long-term use can increase the risk of Alzheimer’s disease later in life, Mikkola says.

Original publication:

Savolainen-Peltonen et al. Use of postmenopausal hormone therapy and risk of Alzheimer’s disease in Finland: nationwide case-control studyBMJ, DOI: 10.1136/bmj.l665.

Contact information:

Tomi Mikkola, tomi.mikkola@hus.fi, tel. +358 50 4271187