A recent study has indicated that living alone in a middle age can increase the risk of dementia or Alzheimer's disease. However, the presence of a partner in life during middle age can reduce the risk.

The researchers in Sweden and Finland, led by Miia Kivipelto, analyzed data collected from 1,449 people. The study subjects were first interviewed in the 1970s and 1980s, when their average age was 50. They were again interviewed after 21 years.

Data analysis revealed that people who were married in midlife had the lowest rates of dementia and Alzheimer's. People who were single at midlife or divorced had 1.5 times higher risk of dementia and 1.8 times more chances to develop Alzheimer's.

It was found that those who were widowed had the highest risk. People who were widowed were 3.3 times more likely to be diagnosed with dementia and 2.5 times more likely to have Alzheimer's.

The researchers found that other factors like education, work, intellectual leisure activities or rich social networks also slow down cognitive decline.

Miia Kivipelto said that the data shows that "supportive intervention for individuals who have lost a partner might be a promising strategy in preventive health care."