A total of 506 people, all aged over 78, were asked by researchers to fill out questionnaires about their personality traits and lifestyle. The personality questionnaire gauged whether those participating were prone to distress while the lifestyle questionnaire measured their level of sociability.
None of the subjects suffered from dementia at the outset. By the end of the six year study period, 144 of the subjects had developed dementia.
Karolinska's researchers found that "people who were socially isolated or inactive but relaxed had a 50 percent lower risk of developing dementia compared with people who were isolated and prone to distress. The dementia risk was also 50 percent lower for people who were outgoing and relaxed compared to those who were outgoing but prone to distress," according to a statement.
"The good news is, lifestyle factors can be modified as opposed to genetic factors which cannot be controlled. But these are early results, so how exactly mental attitude influences risk for dementia is not clear," said study leader Dr Hui-Xin Wang.
The results of the study have been publish in the medical journal of the American Academy of Neurology.