Stress is on the rise for women and it can lead to a host of health problems over the lifespan including depression, anxiety, obesity, and Alzheimer’s disease, an incurable brain disorder that destroys memory and the ability to perform simple tasks. Women, in fact, are more likely than men to develop Alzheimer’s disease. At first, researchers thought this was because women lived longer than men, however, more and more research is pointing to other factors, including stress.
A new study published in the International Journal of Geriatric Psychology sought to find out whether stressful life experiences such as divorce, and more significant traumatic events, such as physical assault during midlife are associated with memory decline in later life, and if so, whether that association was apparent in both men and women.
“We have long known that stress can cause memory impairment in some individuals, and that experiencing stress increases the risk for dementia, including the most common cause of dementia in older people, Alzheimer’s disease,” study author Dr. Cynthia A. Munro. “This is thought to be due to the effects of the stress hormone cortisol on the hippocampus, which is the part of the brain that is crucial for memory. Interestingly, the effects of aging on the cortisol response to stress is much greater (three times greater) in women compared to men. Given these associations, we theorized that perhaps the reason women are more likely than men to develop Alzheimer’s disease is because with advancing age, women become increasingly vulnerable to the effects of stress on memory. In this study, we predicted that we would find a link between stress at midlife and later memory decline in women but not in men.”
Women have a one in five chance of developing Alzheimer’s disease by the age of 65 compared to men who have a one in eleven chance. Over 60 per cent of people with Alzheimer’s disease are women. In the U.S., that means over three million women are living with the disease out of a total of five million people who struggle with Alzheimer’s each day.
Dr. Munro believes that the real key to battling Alzheimer’s disease is to prevent it altogether. One way to do that is to delay or prevent the development of memory decline, which is often the first symptom of Alzheimer’s disease and other types of dementia.
“Given what we know about sex differences in stress and risk of Alzheimer’s disease it makes sense to focus on how we respond to stress as a way to reduce the risk of Alzheimer’s disease,” Dr. Munro told us. “My hope is that treating people who are most vulnerable to the effects of stress early in life will go a long way toward preventing the development of dementia in later life.”
Researchers looked at data from a study of 909 men and women who were interviewed as part of their study visits. At the third interview, which took place when they were in their late forties on average, researchers asked them to report whether they experienced various stressful life experiences such as divorce or job loss, and whether these experiences occurred more recently or over a year ago.
“We also asked participants whether they experienced any traumatic experiences, such as combat or rape, again either within the prior year or in the remote past,” Dr. Munro told us. “At both study visits, participants completed memory tests. To test our theory, we analyzed whether the change in memory test performance between the third and fourth visits was related to the amount of stressful experiences and traumatic events reported at the third visit.”
Researchers also examined whether events that occurred within the past year of the third visit or those that were reported to have occurred more than a year prior to the third visit predicted memory decline between the third and fourth visits.
The researchers found that higher stress during mid-life was associated with greater decline in memory over a decade later in women, but not in men. And specifically, stressful life experiences that occurred within the year prior to the third visit, but not those that occurred over a year prior to the third study visit. In contrast, traumatic events during mid-life, regardless of when they occurred, were not related to memory decline in men or women.
“I am always surprised when a study turns out the way I predict, as so many factors could affect the outcomes, but we had predicted that we would find an effect of stress in women but not in men, so I was relieved that our prediction was borne out by our findings,” Dr. Munro told us. “I was surprised that having traumatic stressors were not related to memory decline in either sex. Because traumatic experiences are stressful, I assumed that if anything, trauma would lead to greater memory decline than stressful life experiences.”
Dr. Munro and colleagues believe that this might be because stressful experiences such as divorce or death of a family member leads to ongoing changes that result in other stressors (such as negotiating child custody arrangements or moving to a new home). They suspect that because even though traumas are by nature severe, they are often time-limited, albeit this is certainly not always the case.
“My hope is to prevent Alzheimer’s disease in everyone, not only in women, and I don’t think that the path to developing the disease is necessarily the same for everyone,” Dr. Munro told us. “However, if we are correct that reducing the stress response will reduce the risk of dementia, it remains to be determined whether this approach will be an effective treatment for everyone.”
Patricia Tomasi is a mom, maternal mental health advocate, journalist, and speaker. She writes regularly for the Huffington Post Canada, focusing primarily on maternal mental health after suffering from severe postpartum anxiety twice. You can find her Huffington Post biography here. Patricia is also a Patient Expert Advisor for the North American-based, Maternal Mental Health Research Collective and is the founder of the online peer support group - Facebook Postpartum Depression & Anxiety Support Group - with over 1500 members worldwide. Blog: www.patriciatomasiblog.wordpress.com