Stressful experiences in middle age are associated with greater memory loss among women later in life, but this link is not found in men, a new study says.
It included more than 900 adults who were assessed twice in the early 1980s; once between 1993 and 1996; and once between 2003 and 2004. Their average age was 47 at their third visit in the '90s.
Mental skills tested
During that visit, about 47% of men and 50% of women said they'd had at least one stressful event during the past year, such as a marriage, divorce, birth of a child, death of a loved one, job loss, severe injury or sickness, a child moving out or retirement.
At the third and fourth visits, participants' mental skills were tested. To gauge their memory, they were asked to recall 20 words spoken aloud immediately after hearing them and again 20 minutes later.
At the third visit, they recalled an average of eight words immediately and six words later. At the fourth visit, the numbers were seven and six, respectively.
Participants were also asked to identify words spoken to them from a written list of 40. During the third visit, participants correctly identified an average 15 words, compared to about 14 at the fourth visit.
At the fourth visit, word memory among women who'd had at least one stressful midlife event declined by an average of one word – twice the level of others.
At the fourth visit, the ability to recognize words also fell by an average of 1.7 words for women with at least one stressful mid-life event, compared with a 1.2-word decline for others.
Stress response greater in women
Men who reported stressful midlife events did not experience a similar decline, according to the study published in the International Journal of Geriatric Psychiatry.
The findings add to evidence that stress hormones affect brain health of women and men differently, according to the researchers. They said previous research found that the effect of age on the stress response is three times greater in women than in men, and that stressful life events can cause temporary memory and thinking problems.
They also noted that women have a greater risk of Alzheimer's disease than men. One in six women over age 60 will develop the disease, compared with one in 11 men, according to the Alzheimer's Association.
"We can't get rid of stressors, but we might adjust the way we respond to stress, and have a real effect on brain function as we age," said study author Cynthia Munro. She's an associate professor of psychiatry and behavioural sciences at Johns Hopkins University School of Medicine in Baltimore.
"And although our study did not show the same association for men, it sheds further light on the effects of stress response on the brain with potential application to both men and women," she added in a university news release.
If future research shows that stress response does play a role in Alzheimer's and other types of dementia, then finding ways to control the body's chemical reactions to stress may prevent or delay mental decline, according to the study authors.
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