Hormone Therapy Use May Increase Or Decrease Dementia Risk Depending Upon Timing

Compared to women never on hormone therapy, those taking hormone therapy only at midlife had a 26 percent decreased risk of dementia; while women taking HT only in late life had a 48 percent increased risk of dementia, according to Kaiser Permanente researchers.   Women taking HT at both midlife (mean age 48.7 years) and late life had a similar risk of dementia as women not on HT, according to the study which appears in the Annals of Neurology. The study was funded in part by the National Institutes of Health.

Although previous research has shown that initiation of postmenopausal estrogen hormone therapy in late life increases the risk of dementia, animal studies and some observational studies have suggested that midlife use of HT may be beneficial. This is the first observational, long-term study to directly compare the effect of hormone therapy status in both midlife and late life on risk of dementia.

"This study is unique because we had a group of women who were on HT in midlife only and could look at their dementia risk over time, and we found a modest, protective association. We also found that if you start HT late in life, you have a 50 percent increased risk of dementia, which is consistent with other studies," said study lead author Rachel Whitmer, PhD, a research scientist with the Kaiser Permanente Division of Research in Oakland, Calif. "Women should speak with their doctor about what's best for their individual situation, however it appears from this study that women who are on short-term HT in midlife may benefit from a modest protective association, while initiation in late-life can cause harm."

Adjustment for high cholesterol, hypertension and stroke did not reduce the magnitude of the effect of late life HT on increased risk of dementia, according to the researchers. It's also possible that in the group of women who used HT both in midlife and late life; the potential modest benefit of midlife use was counteracted by a negative effect of late life use, they explained.

This study is part of an ongoing body of research at Kaiser Permanente to better understand the modifiable risk factors for dementia.

Limitations of this most recent study include the fact that HT information in midlife was self-reported and therefore researchers do not know the dose or type of HT involved. Also, because the pharmacy database was initiated in 1994, researchers do not have information on the duration of midlife HT.

Source: Kaiser Permanente

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Comments

Thanks for the info. I have my annual physical coming up in two weeks and I am going to discuss this with my doctor. I continue to fret over the pros and cons of hormone therapy but am doing well and also fret if I go off it my body might make drastic changes...

Very interesting information. Makes for an interesting problem, what with the issue of HRT and breast cancer risk. I certainly would be willing to go back on hormones if it would decrease the risk of dementia.

Thought provoking. It now poses a problem, go on HRT and decrease risk of alzheimer's, but increase risk of breast cancer. I personally am more afraid of alzheimer's at this point, so likely will be going back on HRT. Thanks

This is very thought provoking. I am in my 60's now but was taking HRT from age 49 for 10 years, then because of the breast cancer risk I thought I'd better stop. Since then I've had a noticable decline in my skin, bones and mental efficiency. I thought this was a natural age decline but it has happened quite quickly. Words come out of my mouth that I didn't mean to say, I forget things rapidly, etc. etc. So, if , as you state 'HRT as that age has a good effect, It's not helped me. How do we know if this is just part of the aging process or that it would have happened anyway? EDITOR'S NOTE; Probably a good idea to recheck your postmenopause profile with a health profession.

This is a real interesting study. It's a mystery to me why HT would decrease risk of dementia if taken earlier in life but increase risk later. Maybe it has to do with the body's natural momentum towards cellular decline. Maybe using HT in the declining years is like crashing into a wall, the body is almost shocked! I don't really know, but great report.

My mother had HRT and never had a problem thank god. It must be terrible for people who do, although HRT can really make life bearable.

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