London, Aug 17 (IANS) Women, who experience repeated stress and anxiety in mid-life, can face up to twice the risk of developing dementia than their normal peers.

Swedish researchers followed the progress of 1,415 women, with three surveys in 1968, 1974 and 1980 to assess the levels of psychological stress. The women were aged between 38 and 60 at the beginning of the study, says a Daily Mail report.

Stress was defined as a sense of irritation, tension, nervousness, anxiety, fear or sleeping problems lasting a month or more.

Researcher Lena Johansson from the University of Gothenburg, Sweden said: "This is the first study to show that stress in middle age can lead to dementia in old age, and confirms similar findings from studies of animals."

During the study, 161 women developed dementia, mainly in the form of Alzheimer's. Dementia risk was 65 percent higher in women who suffered frequent stress in middle age, reports the journal Brain.

The risks of developing dementia went up as women responded to more than one survey by saying they were frequently stressed.

The risk increased by 73 percent when women reported frequent or constant stress on two occasions, and more than doubled when all three surveys showed they were stressed.