PRAGUE (Deutsche Presse-Agentur (dpa)) -- Elderly people with few worries and little stress are probably better protected against the progress of Alzheimer's disease than their peers who are under psychological pressure.

While stress alone is not thought capable of causing Alzheimer's, it can promote the kind of brain degeneration that leads to symptoms of dementia, according to Argentine researchers attending a recent congress of the European Neurological Society in Prague.

The researchers said this was good reason to pay greater heed to psychological health among the elderly.

They reached their findings after following 107 patients with mild to moderate symptoms of the disease, with an average age of 72. There was an average gap of 2.5 years between the initial symptoms and diagnosis.

Healthy people with similar age, gender and educational characteristics formed the control group. The subjects, as well as relatives and carers, were asked whether there had been any noteworthy events in the three years before diagnosis.

It was apparent that 73 per cent of the Alzheimer's patients had been under severe psychological stress, frequently through the death of a partner or a child, being subjected to violence, such as a criminal assault or a car accident, with limited physical but significant psychological consequences.

Only 24 per cent of those in the control group had experienced similar events.

Alzheimer's is said to be the most common form of dementia in the world, with the risk factors found to be age, high blood pressure, diabetes, and physical and mental idleness.

According to the Argentine team, the effect of environmental factors, such as stress, on the origins of Alzheimer's still have to be investigated.

Copyright 2012 dpa Deutsche Presse-Agentur GmbH