Midlife Stress and Alzheimer's: What's the Connection?

Stressful experiences in middle age are associated with greater memory loss among women later in life. But this link isn't found in men, according to a new study.

The study, in International Journal of Geriatric Psychiatry, included more than 900 adults who are Baltimore residents 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 and 63 percent were women. Residents had participated in the National Institute of Mental Health's Epidemiologic Catchment Area.

During their third interview, about 47 percent of men and 50 percent of women said they'd experienced at least one stressful during the past year. Such events included marriage, divorce, birth of a child, death of a loved one, job loss, severe illness, a child moving out or retirement. They were also asked if they'd undergone a traumatic event such as threats, natural disasters, rape and physical attacks, or watched another person get injured or die. Learn how to manage common causes of stress.

The number of men and women reporting a traumatic experience was nearly even at 22 percent of men and 23 percent of women. The same went for stressful life events, with 47 percent of men and 50 percent of women saying that they had experienced at least one during the previous year. Here is how to manage anxiety with self-care.

At their third and fourth appointments, all participants took a standardized memory test. They were asked to remember 20 words said 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. They remembered seven words immediately and six words later at the fourth visit.

Participants were also asked to find words they were told on a 40-word written list. Participants accurately found an average of 15 words on the third visit. They identified about 14 words at the fourth visit.

Word memory for women at the fourth visit who'd had at least one stressful midlife event decreased by an average of one word. That was nearly twice the level of others.

Also at the fourth visit, the ability to recognize words 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.

Still, men who reported stressful midlife events didn't experience a similar decline.

Findings add to evidence that stress hormones affect women's and men's brain health differently. Previous research found that effect of age on the stress response is three times greater in men than women and that stressful life events can cause temporary memory and thinking problems.

Researchers (who were from Johns Hopkins University School of Medicine) 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.

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.

Stopping stress is almost impossible. But it may be possible to eventually turn to medications to change the body's reaction to stress. These medications are currently being developed.