Hormone Therapy

In the beginning, we thought estrogen was good for women. After all, when estrogen therapy was first studied, investigators thought they were seeing less heart disease and Alzheimer’s among the women who took estrogen.

Why? Because when researchers looked at women who did and didn’t have heart disease or Alzheimer’s, and asked these women to recall their hormone use, those without these problems were more likely to have taken estrogen. Thus hormone replacement therapy (HRT) was deemed a good thing. However, as time went on, the disadvantages of these "looking backwards" studies became more obvious: A woman who took HRT to stay healthy might also be more likely to eat right, exercise, and not smoke.

This concern (among others) gave rise to the Women’s Health Initiative (WHI), the most comprehensive "forward-looking" study of HRT. The WHI followed two groups of postmenopausal women, randomly giving half of the group HRT and the other half placebo. The results showed a slight increase in heart disease and possibly a slight increase in Alzheimer’s in the group taking HRT. But many pro-estrogen physicians were unconvinced by the negative WHI results, and they’ve been reanalyzing the data. One approach they’ve taken is to study those women who entered the WHI just as they were starting menopause, rather than look at the entire WHI group, which included much older women. Some of these analyses suggest women who start HRT earlier do better than those who start it later.

In a new study with a slightly different twist—the WHI Memory Study—investigators again looked at women in the WHI. This time they asked if they could relate the development of Alzheimer’s disease to estrogen use before the women entered the WHI. The results suggest that early estrogen may protect against Alzheimer’s, however this study needs to be taken in context.

First, all the news reports for this study are based on a short presentation at a national meeting, accompanied by only a brief written description of the study. Until it is published in a peer-reviewed journal, we won’t be able to fully evaluate the methods or the data. This is not a criticism, it’s just part of the scientific process. Exciting results get talked about at national meetings and generate quick media attention, but the full story comes out a few months later.

Second, the investigators relied on women’s recollection of their estrogen use. These recall studies are tricky, even for the most careful investigators, since self-reporting is often inaccurate. And it was this concern, in part, that led to the WHI in the first place. I’m not saying that these concerns invalidate the results of this study. Instead, I’m urging caution before embracing the results of any "study of the month."

So, does estrogen prevent Alzheimer’s? Maybe. Does it matter when you take estrogen? No one is really clear on that either. What we do know is that the difference among those taking estrogen and those abstaining isn’t large. My own feeling: If preventing Alzheimer’s is the only reason you’re taking estrogen, you probably shouldn’t bother. I suspect you’d be better off taking a daily walk and doing Sudoku.