Middle-aged single people are twice as likely to develop dementia than married ones or those with a partner, Swedish researchers have found.
A recent study by the Karolinska Institute suggested that the problem might be even greater for some people like divorcees who remained single as they had three times more risk of dementia, while those who were widowed at a young age and stayed single faced six times greater chance.
The research looked at 1,449 people from a Finnish database, who were asked about their relationship status in mid-life, then revisited 21 years later to see if they had developed dementia, BBC reported.
In total, 139 of them had some sort of cognitive impairment, and Alzheimer's was diagnosed in 48 of these.
Even after other factors that might have an impact on dementia were adjusted for, the study consistently showed people with partners as less prone to the illness.
The researchers said that social interaction between couples might be the reason for these results.
"Living in a couple relationship is normally one of the most intense forms of social and intellectual stimulation. If social and cognitive challenges can protect against dementia, so should living as a couple,” said Krister Hakansson, who led the study.
"Living in a couple means that you are confronted with other ideas, perspectives and needs. You have to compromise, make decisions and solve problems together with someone else, which is more complicated and challenging. It is probably easier to get stuck in your own habits and routines if you live by yourself," he added.
"Cognitive and intellectual stimulation has been reported to be protective against dementia in general. This study points to the beneficial effects of a married life," Hakansson said.
The results of the study were released at the Alzheimer's Association's 2008 International Conference here.