A recent analysis of data on more than 900 adults by Johns Hopkins researchers has linked stressful life experiences among middle-aged women—but not men—to greater memory decline in later life.
The researchers said their findings, published the “International Journal of Geriatric Psychiatry,” align with documented higher rates of Alzheimer's disease in women than men and add to evidence that stress hormones play an uneven gender role in brain health.
Although the researchers cautioned that their study was designed to show correlation and not cause and effect, they suggested if future studies demonstrate that stress response does factor into the cause of dementia, then strategies designed to mitigate the human body's reactions to stress may prevent or delay the onset of cognitive decline.
"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 Cynthia Munro, associate professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine. "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."
Prior research by other investigators showed that the effect of age on the stress response was three times greater in women than in men. Separately, other research has shown that stressful life experiences can result in temporary memory and cognitive problems. According to researchers, stress reduction hasn't received as much attention as other factors that may contribute to dementia or Alzheimer’s disease. They suggested that it might be worth exploring stress management techniques as a way to delay or prevent disease.
According to the Alzheimer's Association, “almost two-thirds of Americans with Alzheimer's are women. Of the 5.6 million people age 65 and older with Alzheimer’s in the United States, 3.5 million are women.” Not only are women more likely to have Alzheimer's, but they are also more likely to be caregivers of those living with Alzheimer's—not an easy task. “Female caregivers may experience higher levels of depression and impaired health than their male counterparts. Evidence suggests these differences arise because female caregivers tend to spend more time caregiving, to take on more caregiving tasks, and to care for someone with greater cognitive, functional and/or behavior problems.”
For the Johns Hopkins study, Munro and her team used data collected on 909 Baltimore residents for the National Institute of Mental Health Epidemiologic Catchment Area study. Some 63 percent of the participants were women and 60 percent were white. Participants were an average age of 47 during their mid-life check-in in the 90s.
Participants met with researchers four times: during the third visit, participants were asked if they had experienced a traumatic event in the past year such as combat, rape, a mugging, some other physical attack, watching someone else attacked or killed, receiving a threat, or living through a natural disaster. Approximately 22 percent of men and 23 percent of women reported at least one traumatic event within the past 12 months before their visit.
They also were asked about stressful life experiences such as a marriage, divorce, death of a loved one, job loss, severe injury or sickness, a child moving out, retirement, or the birth of a child. About 47 percent of men and 50 percent of women reported having at least one stressful life experience in the year before their visit.
Munro's team found that having a greater number of stressful life experiences over the last year in midlife in women was linked to a greater decline in test performance. Interestingly, they didn't see the same trend in women who had traumatic events. Munro said that this finding suggests that ongoing stress, such as that experienced during a divorce, may have more of a negative impact on brain functioning than distinct traumatic events.
The researchers did not see an association in men between a drop in word recall or recognition and experiencing either stressful life experiences or traumatic events in midlife. Stress experienced much earlier in life also wasn't predictive of cognitive decline later in either men or women.