The response to common life events may trigger long lasting physiological changes in the brain, say Swedish researchers looking at some of the factors contributing to dementia in later life.
They base their findings on 800 Swedish women whose mental health and wellbeing were tracked over a period of almost 40 years as part of a larger population study which started in 1968.
The women, who were all born in 1914, 1918, 1922 and 1930, underwent neuropsychiatric tests and examinations in 1968, when they were in their late 30s, mid 40s, and 50s, and then again in 1974, 1980, 1992, 2000 and 2005.
At their initial assessment, the women were quizzed about the psychological impact of 18 common stressors, such as divorce, widowhood, serious illness, death of a child, mental illness, alcoholism, personal or partner's unemployment, and social support.
In 1968 one in four of the women had experienced at least one stressful event; a similar proportion (23 percent) had experienced at least two, while one in five had experienced at least three, and 16 percent four or more. The most commonly reported stressor was mental illness in a close family member.
On average, it took 29 years for dementia to develop, with 78 the average age at which the condition was diagnosed.
The researchers found that the number of stressors reported 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 findings, they note, held true even after taking account of factors likely to influence the results, including a family history of mental health problems.
The authors emphasize that further research is needed, 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.
Discuss this article in our forum
Cholesterol meds linked to senior moments
New thinking on vascular disease and Alzheimer's
Sleep meds and dementia may be linked
Source: British Medical Journal