How To Think About Hormones and Dementia

How old a woman is when she takes supplemental hormones may determine whether it helps to protect her against developing dementia later in life, according to a new analysis of data from the Women's Health Initiative that was presented at the American Academy of Neurology annual meeting in Boston.

Readers of this blog will immediately note the "Mighty May" and will mentally rewrite the news as "hormones, depending on when they are taken, may or may not help prevent dementia."

Here's why this research is considered preliminary and not definitive.

The researchers looked at the original Women's Health Initiative (WHI), which conclusively showed a few years ago that years and years of hormone replacement therapy (either estrogen alone or estrogen plus progestin) actually increased the risk of dementia in women 65 and older.

The new analysis was designed to answer the question whether timing matters when starting hormone therapy. But instead of conducting a randomized, controlled clinical trial--which would give a definitive answer but would be costly and unlikely to get many participants because of what has already been shown about long-term hormone therapy--the researchers, led by Victor Henderson of Stanford University in California, looked at the questionnaires the women filled out.

Based on the women's responses, Henderson and his colleagues created a new set of data points that showed which women started hormone therapy early--before menopause or after menopause.

On the basis of those answers, the researchers determined that early hormone therapy was protective, while later therapy--started after age 65--was not.

But the conclusion rests on what the women reported about themselves so it's subject to recall bias.

Also, women who turned to hormone therapy throughout the 1980s and 1990s are known to be healthier overall than those who didn't. In other words they started off healthy, wanted to stay that way and had access to doctors. So even if they accurately remembered whether or not they took hormones, that could simply be a measure of how healthy they were in the first place.

The bottom line: if you're having severe menopausal symptoms and want relief, you may want to consider hormone therapy--but only for one or two years. Taking hormones in the hopes of staving off Alzheimer's or heart disease in the future is still more likely to hurt you than to help you.

On the other hand, if you're worried about dementia, there's compelling evidence that your best bet is to get plenty of exercise and avoid getting hit in the head.

Sources:
1. The Women's Health Initiative
2. Shumaker SA, et al. "Estrogen plus progestin and the incidence of dementia and mild cognitive impairment in postmenopausal women: the Women's Health Initiative Memory Study: a randomized controlled trial," JAMA. 2003 May 28;289(20):2651-62
3. Shumaker SA, et al. "Conjugated equine estrogens and incidence of probable dementia and mild cognitive impairment in postmenopausal women: Women's Health Initiative Memory Study," JAMA. 2004 Jun 23;291(24):2947-58
4. Larson, EB, et al."Exercise is associated with reduced risk for incident dementia among persons 65 years of age and older." Ann Intern Med. 2006 Jan 17;144(2):73-81
5. Guskiewicz KM, et al. "Association between recurrent concussion and late-life cognitive impairment in retired professional football players. Neurosurgery. 2005 Oct;57(4):719-26