The WHIMS study, published in JAMA in 2003, included 4,532 postmenopausal women aged 65 or older. One group took a combination of oestrogen and progestin, the other a placebo. Women taking hormones had about twice the risk of probable dementia: 45 cases compared with 22 per 10,000 women per year.
Why this doesn’t mean “hormones are bad”
This trial was carried out in women aged 65 and over, so its conclusions do not apply to younger women who start hormone therapy early in menopause. We also mentioned that the timing of therapy matters in our article on “brain fog”. The risk of mild cognitive impairment did not differ between the groups.
What this means for you
- Hormone therapy is not prescribed to prevent dementia.
- Make decisions about therapy with your doctor, taking into account your age, symptoms and risks.
- If you are considering therapy, when you start it matters too.
Sources
- Shumaker S. A., Legault C., Rapp S. R. et al. (2003). Estrogen plus progestin and the incidence of dementia and mild cognitive impairment in postmenopausal women: the Women’s Health Initiative Memory Study. JAMA, 289(20), 2651–2662. doi:10.1001/jama.289.20.2651