Certain events in our lives can cause very high levels of stress. From deaths and divorce to losing a job, the stress of these events might last longer than we realize.
A recent study found that Swedish women followed over their lifetimes were more likely to develop dementia if they experienced more high-stress events in mid-life.
The women's risk of dementia and Alzheimer's disease was a little bit higher for each additional stressful life event they had experienced.
It is not clear if stress management therapy or behavioral therapy for women experiencing stressful life events might affect their risk for dementia or Alzheimer's.
This study, led by Lena Johansson, MSc, of the Institute of Neuroscience and Physiology at Gothenburg University in Sweden, aimed to find out whether stress in mid-life or late life might increase women's risk of dementia.
The researchers followed 800 Swedish women who had been born in 1914, 1918, 1922 and 1930.
They had all undergone a psychiatric examination in 1968 as part of another study. Then they underwent follow-up exams in 1974, 1980, 1992, 2000 and 2005.
The researchers surveyed the women at the initial meeting in 1968 regarding 18 different psychological or social events that could cause stress.
These included having gone through a divorce, being widowed, having serious work problems, having a relative who was very ill and similar life occurrences.
Any women who met the criteria for dementia based on the standard psychiatric diagnosis at the time were noted as well.
During the 37 years that the women were followed, 153 of them, or 19 percent, developed dementia, including 104 who developed Alzheimer's disease.
Those who had experienced a higher number of highly stressful events at the first evaluation in 1968 had about 15 percent greater odds of developing dementia and 20 percent greater odds of developing Alzheimer's at some point between 1968 and 2005.
The researchers also measured how much distress the women felt at each of the follow-ups. They were asked if they had experienced a period of distress for at least one month or longer related to everyday circumstances, such as work, health or family.
The participants rated their level of distress on a scale, with distress referring to "feelings of irritability, tension, nervousness, fear, anxiety or sleep disturbances."
Women who had experienced a higher number of stressful events at the first exam were about 1.5 times more likely to feel high levels of distress at that time as well.
Having experienced a higher number of stressors in 1968 meant women were 1.3 times more likely to feel distress in 1974 and 1.3 times more likely to feel distressed in 1980.
Those women were 1.4 times more likely to feel distress in 2000 and in 2005 as well.
Both the numbers of stressful events women had experienced and the amount of distress they had experienced throughout their lives were found to increase their risk of Alzheimer's disease.
Women with long-standing distress had 1.6 times greater odds of developing Alzheimer's disease.
"Our study shows that common psychosocial stressors may have severe and long-standing physiological and psychological consequences," the researchers wrote.
However, they cautioned that more research is needed because stress management techniques and behavioral therapy may end up being helpful for these individuals.
This study was published September 30 in the journal BMJ Open. The authors declared no conflicts of interest.
The research was funded by the Swedish Medical Research Council, the Swedish Council for Working Life and Social Research, the Alzheimer’s Association Zenith Award, the National Institutes of Health/National Institutes on Aging, the Alzheimer’s Association Stephanie B. Overstreet Scholars, The Bank of Sweden Tercentenary Foundation, Swedish Brain Power, Stiftelsen Söderström-Königska Nursing Home, The Foundation for Historical Tjänarinnor, The Hjalmar Svenssons Research Foundation, The Foundation for Professor Bror Gadelius’ Memorial Fund and the University of Gothenburg Sahlgrenska Academy.