Women perform better than men on all memory measures, but these sex differences tend to disappear as women age and enter menopause, according to a study published in the journal Menopause.
These findings highlight the importance of steroid hormones, especially estradiol —a form of the female sex hormone estrogen — in maintaining memory function, and could explain why women are almost twice as likely as men to develop Alzheimer’s disease.
“For years, the dominant thinking in the field was that women were at higher risk of Alzheimer’s disease simply because they tend to live longer,” Dr. Jill Goldstein, the study’s senior author and the director of research at the Connors Center for Women’s Health and Gender Biology at Brigham and Women’s Hospital (BWH) in Boston, said in a news release. “But that idea was perpetuated by research that looked late in life, not at middle age, when key hormonal transitions take place and when changes in memory begin to surface.”
For the study, “Sex differences in episodic memory in early midlife: impact of reproductive aging,” the team of researchers recruited a total of 212 men and women, ages 45 to 55.
They assessed the hormonal and menopause status of the participants as well as their episodic memory, or the memory of autobiographical events; their executive function, such as reasoning, problem solving, and planning; their semantic processing, or attributing meaning to a word; and their estimated verbal intelligence.
Results showed that women outperformed men in all memory measures. Moreover, women who were not in menopause or were in a transition period outperformed postmenopausal women in both associative and episodic verbal memory tests.
The researchers also found that higher levels of estradiol, which has the greatest effect on the brain, was associated with better performance in memory tests across all women studied.
They concluded that memory circuits in the brain begin to change with age, and that steroid hormones (secreted by three “steroid glands”— the adrenal cortex, testes, and ovaries) play a crucial role in maintaining memory function, especially in women.
According to Goldstein, it is now important to determine who is at highest risk of developing Alzheimer’s disease in order to start treatment before disease onset, since treatments given after onset are unsuccessful.
“We hope findings from our cohort will ultimately provide clues early in mid-life with regard to who is at highest risk for the disease in later mid-life, and how this may differ for men and women,” Goldstein said.
She and her team are collaborating with Dr. Philip de Jager, the director of the Translational Neuropsychiatric Genomics Program at the Ann Romney Center for Neurologic Diseases at BWH, to develop a clinical risk tool incorporating genetic risk factors, other factors affecting memory decline, and sex difference, in an attempt to identify people with the highest risk of developing Alzheimer’s disease.