To Prevent Dementia, Is Timing Everything?

The use of hormone therapy (HT) to prevent dementia in women has been controversial, and studies have yielded mixed results. According to the “critical window theory,” HT in perimenopause or early postmenopause is beneficial. Results of a preclinical study and a patient observation study lend strong support to this theory.

Whitmer and colleagues analyzed information on HT and dementia from an observational cohort study of 5504 women, who were postmenopausal and reported midlife HT status at routine checkups in 1964–1973 (age range, 40–55) and were alive in 1994. Four groups were identified: no HT (45% of the sample), midlife HT (25%), late-life HT (1994–1998; 12%), and both mid- and late-life HT (18%). In 1999–2008, dementia was diagnosed in…