Hormone replacement therapy (HRT), a treatment often used by women to help with the uncomfortable symptoms of menopause, might be linked with a higher chance of developing dementia, according to a large study. Menopause is a natural biological process where a woman stops menstruating and fertility ends.
The researchers found that women in their 50s who used HRT had a 24% higher chance of developing dementia, including Alzheimer's disease (AD), twenty years later compared to women who didn't use HRT. This increased risk existed even for women who only used HRT for a short time when they first started menopause.
However, the scientists and other experts highlight that we need more research to confirm if the higher risk of dementia is actually caused by HRT. It's also possible that women who need HRT may already have other factors that make them more prone to dementia.
"We can't definitively say whether our findings show a direct cause-and-effect relationship, or if they just highlight an increased risk of dementia in women who need HRT," said the lead researcher, Dr. Nelsan Pourhadi, from the Danish Dementia Research Centre.
Interestingly, these findings support evidence from the Women's Health Initiative Memory Study (WHIMS), the largest study on menopausal hormone therapy and dementia conducted to date.
Before WHIMS was published in 2003, HRT was widely prescribed to alleviate menopausal symptoms. However, the WHIMS study, which included more than 4,000 women aged 65 or older, showed that HRT was associated with a two times higher risk of dementia.
Since then, studies have produced mixed results, which has stirred up a controversy regarding the safety of HRT. To dig deeper into the issue, Dr. Pourhadi and his team conducted an observational study from 2000 to 2018, following more than 60,000 Danish women aged 50 to 60 years. Their research indicated that about 5,600 women developed dementia, with nearly 1,460 of these diagnosed with AD.
Nearly 18,000 participants in the study received HRT. Half started the treatment before turning 53 and half stopped within four years. Approximately 90% used oral medications, which included a combination of estrogen and progestin.
The study found that the women who used estrogen-progestin therapy had a 24% increased risk of developing dementia compared to those who did not use HRT. The risk of dementia increased similarly for both continuous (daily) and cyclical (10 to 14 days per month) treatment regimens.
The study also found that longer use of HRT was linked with a greater risk. Those who used it for one year or less had a 21% increased risk, while those who used it for 12 years or more had a whopping 74% increased risk.
However, these findings do not imply that HRT should be completely avoided. It simply underscores the need for further research to understand the effects of HRT better. Meanwhile, it's important for women to discuss with their healthcare providers to determine the best course of action for their health.