GROWING EVIDENCE THAT ESTROGEN PROTECTS COGNITION

Some sex hormones appear to be important for more than just sex. In particular, there is growing evidence that estrogen protects neurons and, hence, cognition. A brief article in *Science* summarizes the latest developments.

It's been known for 20 years that estrogen encourages the growth of neurons in developing embryos, but now it seems that this is also true for adults. Estrogen stimulates formation of axons and dendrites and has a potent antioxidant effect that protects neurons. Studies in rats and monkeys have found an association between high blood levels of estrogen and performance on various cognitive tasks. A previous study of women with mild Alzheimer's disease showed that estrogen therapy improved verbal memory and attention; the effect disappeared when estrogen was discontinued. Several large studies have found an association between increased estrogen levels and diminished risk for developing Alzheimer's: One of these recently estimated that taking estrogen for more than a year reduces the risk by up to 5 percent annually.

Comment: The acid test of whether estrogen improves cognition or protects against Alzheimer's will be the Women's Health Initiative study, a large randomized trial of hormone replacement therapy. Meanwhile, drug companies are racing to produce estrogen-like molecules that may exert similar benefits without producing estrogen-induced tumors in women or feminizing effects in men. --AL Komaroff

Published in Journal Watch 16 May 1997

Estrogen stakes claim to cognition.

Wickelgren I, Science 1997 May 2; 276:675-678.
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