Swedish researchers have found that a lot of stress in middle age heightens the risk of dementia in late life. The response to common life events may trigger long-lasting physiological changes in the brain, say the authors.
They base their findings on 800 Swedish women whose mental health and well-being was formally tracked over a period of almost 40 years as part of the larger Prospective Population Study of Women in Gothenburg, Sweden, which started in 1968, according to a press release. The women underwent a battery of neuropsychiatric tests and examinations in 1968, when they were in their late 30s, mid 40s, and 50s, and then again in years later.
At their initial assessment, the women were quizzed about the psychological impact on them of 18 common stressors, such as divorce, widowhood, serious illness or death of a child, mental illness or alcoholism in a close family member, personal or partner's unemployment, and poor social support.
Between 1968 and 2006, around one in five (19 percent or 153 of them) developed dementia, 104 of whom developed Alzheimer's disease. On average, it took 29 years for dementia to develop, with 78 the average age at which the condition was diagnosed, found the study.
The number of stressors reported by the women in 1968 was associated with a 21 percent heightened risk of developing Alzheimer's disease and a 15 percent heightened risk of developing any type of dementia, the analysis showed. The findings, published in the British Medical Journal, held true even after taking into account other factors that might influence the results, such as a family history of mental health problems.
The authors said that further research was needed to confirm the results of their study. But they suggest that "stress may cause a number of physiological reactions in the central nervous, endocrine, immune and cardiovascular systems, " and point to other studies showing that stress can cause structural and functional damage to the brain and promote inflammation.
Research has also shown that stress hormones can remain at high levels many years after experiencing a traumatic event.
There's no known way to prevent Alzheimer's disease, which affects more than 5 million Americans and is the sixth leading cause of death in the United States. But a study released earlier this summer identified a biomarker associated with the risk of developing it. The study found that this potential biomarker may be present in the cerebral spinal fluid at least a decade before signs of the disease appear.