When a Danish study examining the link between hormone replacement therapy (HRT) and dementia was published in late June, the open-ended news headlines gave women around the world collective whiplash. Hadn’t we just established, after decades of suffering in silence (thanks to alarmist news reports about a previous study, the Women’s Health Initiative, trumpeting that taking a combination of estrogen and progestin to treat menopause symptoms increased the risk of breast cancer), that the benefits of hormone treatment greatly outweighed the risks? That HRT was, for the vast majority of women, safe and beneficial—indeed, crucial for overall physical and mental health and longevity? The last thing we need is more misinformation about menopause, so we went to Lisa Mosconi, PhD, director of the Alzheimer's Prevention Program at Weill Cornell Medicine/NewYork–Presbyterian and author of the forthcoming book The Menopause Brain, for clarification and context:
Here is my bottom line: The study we’re talking about is only one study. There are many more reports on the relationship between HRT and risk of dementia, many of which show protective associations. The best and only way to get a clearer picture is to do a meta-analysis (integration) of all available data, which we have done. The paper is under review, and I’ll share it as soon as it is published. Here’s what you need to know in the meantime:
A summary of the new study:
- The study examined Danish medical records, including 5,589 women with dementia and 55,890 without dementia. It explored whether HRT use was associated with a higher risk of dementia.
- All women had a uterus and therefore used “combined” HRT, mainly
oral estrogen along with a synthetic progestin.
What you may have heard in the news:
- HRT was associated with a 24 percent increased risk of dementia (an umbrella term for a number of diseases that affect cognition).
What you also should have heard:
- The actual numbers: 31.9 percent of women in the dementia group and 28.9 percent of those in the control group used HRT. A much less frightening difference.
- Specifically for Alzheimer’s disease, the risk was not significantly increased by taking HRT for more than four to eight or 12 years.
- Those who developed dementia had lower education, lower income, and more risk factors like hypertension, diabetes, and thyroid disease, which could have influenced the results.
- These results apply only to oral estrogen with a synthetic progestin.
- There is no evidence that bioidentical estradiol taken alone, transdermal estrogen, and/or bioidentical progesterone increase the risk of dementia.
- This study does not prove that HRT causes dementia.
- The @menopause_society issued a statement that this study should not change practice. Put simply, there is no reason to stop HRT.
As always, it’s crucial to look at the bigger picture. There are other studies showing protective or neutral effects of HRT against Alzheimer’s and dementia. We are working on integrating all available data to provide a more accurate and comprehensive view.