Marriage appears to be a strong and favorable factor in a person’s risk of developing dementia, with evidence suggesting that married people are at considerably lower risk than people who never marry or those who have lost a partner.
The study, “Marriage and risk of dementia: systematic review and meta-analysis of observational studies” published online in the Journal of Neurology Neurosurgery & Psychiatry, attributed the social interaction that comes with living with another as important to strengthening “cognitive reserve,” or the brain’s ability to be more resilient to damage caused by aging or disease.
Researchers relied on data from 15 studies published through 2016, with findings were drawn from a population of more than 800,000 and spanning Europe, North and South America, and Asia. Married people were between 28 and 80 percent of the various studies’ focal group, those who were widowed between 8 and 48 percent, divorced between 0 and 16 percent, and lifelong singletons, or those never married, between 0 and 32.5 percent.
Pooled analysis showed that, taking into account age and gender, singletons were 42 percent more likely to develop dementia than married people. For the authors, these findings indicate that there is evidence of a potential role of marital status on dementia risk.
“We found that people who are lifelong single have a 42% higher risk and that those who are widowed have a 20% higher risk of developing dementia than those who are married in studies adjusted for age and sex,” they wrote. “We found no evidence that dementia risk in divorced people differs from married people.”
Part of the higher risk found in the never-married, the researchers suggested, was due to their overall poorer physical condition.
This trend, however, seems to be decreasing over time — the analysis spanned publications over years — with more recent studies indicate that singletons are only 24 percent more likely to develop dementia, the study reported.
Researchers suggested that marriage may help both partners lead healthier lifestyles, including exercising more, eating a healthier diet, smoking and drinking less, and particularly by having more opportunities for social engagement — all of which have been associated with decreased risk of dementia compared to single people.
Widowed people were found to be 20 percent more likely to develop dementia than those still living with a spouse, although the strength of this correlation was weaker at higher educational levels. The stress of mourning, they reported, could impair nerve signaling and cognitive abilities in a grieving widow or widower.
Because the findings are based on observational studies, no firm correlations about cause and effect can be drawn, the researchers said.
Still, they concluded: “The magnitude of effect of marital status on dementia is higher than the risk for mortality in unmarried compared with married people … supporting the idea that marriage’s effect on dementia risk is more than just improving physical health and that there may a direct cognitive benefit … Our findings, from large populations, across numerous countries and time periods are the strongest evidence yet that married people are less likely to develop dementia.”