Being married could help stave off dementia, a new study has suggested.

Levels of social interaction could explain the finding, experts have said, after the research showed that people who are single or widowed are more likely to develop the disease.

Experts conducted an analysis of 15 studies which held data on dementia and marital status involving more than 800,000 people from Europe, North and South America, and Asia.

Their study, published in the Journal of Neurology, Neurosurgery, and Psychiatry, concluded that lifelong singletons have a 42% elevated risk of dementia compared with married couples.

Those who have been widowed had a 20% increased risk compared with married people, they found, but no elevated risk was found among divorcees compared with those who were still married.

The researchers, led by experts from University College London, said previous research has shown that married people may adopt healthier lifestyles. They may also be more likely to be socially engaged than singletons.

Meanwhile, the effect observed in people who have been widowed could be due to stress that comes with bereavement, they added. Another explanation could be that developing dementia could be related to other underlying cognitive or personality traits.

Commenting on the study, Dr Laura Phipps of Alzheimer’s Research UK, said: “There is compelling research showing married people generally live longer and enjoy better health, with many different factors likely to be contributing to that link. People who are married tend to be financially better off, a factor that is closely interwoven with many aspects of our health.

“Spouses may help to encourage healthy habits, look out for their partner’s health and provide important social support. Research suggests that social interaction can help to build cognitive reserve – a mental resilience that allows people to function for longer with a disease like Alzheimer’s before showing symptoms.

“Staying physically, mentally, and socially active are all important aspects of a healthy lifestyle and these are things everyone, regardless of their marital status, can work towards.”