Mid-life stress linked with dementia later in life

Mid-life stress may increase a woman's risk of developing dementia and Alzheimer's later in life, new research reveals.

The recent study, published in the British Medical Journal, looked at 800 Swedish women in their 30s, 40s, or 50s and followed them at regular intervals over four decades until 2005.

The women were initially asked about whether they experienced stressful life events such as divorce, loss of a child and illness in their mid-life. They were also asked about symptoms of distress associated with those time periods -- including fear, sleeping problems and irritability.

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The researchers discovered that those who coped with stressful events in mid-life had a 21 per cent heightened risk of developing Alzheimer's, and a 15 per cent increased risk of developing any type of dementia.

And in fact, the more stressful the events, the higher the dementia risk.

"Our study shows that common psychosocial stressors may have severe and longstanding physiological and psychological consequences," says lead author Lena Johansson from Gothenburg University in Sweden.

The findings held true even after controlling for factors likely to influence the results, including a family history of mental health problems.

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While the researchers are unclear about why the association between stress and dementia exists, they speculate that stress hormones may cause significant alteration in the brain.

"Stress may cause a number of physiological reactions in the central nervous, endocrine, immune and cardiovascular systems," say the researchers.

It is also known that stress hormones can affect blood pressure and blood sugar levels, and can remain high years after traumatic events.

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