Nulliparity and late menopause are associated with decreased cognitive decline.

Changes in Mini-Mental State Examination (MMSE) scores were examined over a median of 12.8 years in a population of 361 community-dwelling postmenopausal women who had never received estrogen replacement therapy. In a linear regression model that took into account age, education, race, surgical versus natural menopause, use of birth control pills, and MMSE score at baseline, it was found that nulliparous women and women who went through menopause later in life had significantly less cognitive decline. These results suggest that greater lifetime exposure to endogenous estrogen may be associated with less age-related cognitive decline.