Estrogen and Cognition: A Matter of Months?

In this chapter we address the controversies found in studies investigating the effect of estrogen treatment on cognitive function. There is ample biological evidence to suggest that estrogens can protect the aging brain. Observational studies have often shown that women taking hormones are protected against dementia. However, these studies are contaminated by report bias and healthy user bias. Women who have dementia are more likely to forget that they have used hormones in the past and use of hormones for menopausal complaints was part of a healthy life style pattern for many women. This makes it difficult to disentangle positive effects of hormones per se. In addition, several large treatment studies suggested that older women who use hormone treatment for a prolonged period of time have an increased risk of dementia. Our metaanalyses suggest that estrogen treatment only has positive effects on cognition for a number of months regardless of age of women. In older women long term effects can even be negative. Whether the outcome may be different using different hormone regimens or for subgroups of women remains to be investigated.

Keywords: Alzheimer’s Disease; Estrogens; Cognitive Function; Hormone Treatment; Memory; Postmenopausal; Estradiol.