Marriage affects dementia risks, in a surprising way. A recent study found that people who are married are more likely to be diagnosed with dementia than unmarried people. Writer Shalini Kathuria Narang shares the research results.
Unmarried people are at least 50% less likely to experience cognitive decline in comparison to their married counterparts, according to an 18-year research study published in April 2025. Based on the study findings from the National Alzheimer’s Coordinating Center (NACC) (which has one of the largest, oldest, and most powerful Alzheimer’s datasets), unmarried adults were at lower dementia risk, including for Alzheimer’s Disease and Lewy Body Dementia, as compared to married adults.
The study results have debunked the traditional notions that marriage provides not only social, psychological, and economic benefits but is also related to better health and longevity.
The study findings contradict most previous longitudinal studies that have reported that married individuals have a lower risk of cognitive impairment and dementia in comparison to unmarried individuals.
The recent study found that widowed, divorced, and never-married older adults across all varied races, ethnicities, economic, and educational groups had a lower dementia risk. All unmarried groups were also at a lower risk of progression from mild cognitive impairment to dementia.
Other studies have shown that in certain cases divorce can lead to increased happiness and life satisfaction that may potentially protect against dementia risk. There is also evidence indicating an increase in social participation after partner bereavement in case of widowed individuals.
Never-married people have been found to socialize more with friends and neighbors and are more likely to engage in healthier social behaviors than their married counterparts. Another contributing factor for their protection from dementia may be that besides being better at maintaining their social ties, single people also involve themselves and prioritize a greater variety of interesting and unique experiences, such as travel. Many married people reported getting so busy in careers and chores around raising children that they do not allocate time or resources towards an active and independent social life. The study also found that married individuals tend to have less social integration and are engaged in less frequent and lower-quality interactions in their networks of friends, family, colleagues, and others.
The positive aspects of well-being and good social ties are numerous and are being actively promoted as protective factors against loneliness, isolation, depression, and dementia, as affirmed by the World Health Organization.
Effects of the quality of the marriage
When considering how marriage affects dementia risks, the quality of the marriage seems to matter, too. There is substantial evidence that the health benefits of marriage appear to hold true only for high-quality marriages. In contrast, individuals who are unhappy in their marriage, an indicator of marital quality, are more likely to have equal or worse health and mortality risk compared to those who are widowed, divorced, or never-married.
The findings could indicate delayed diagnoses among unmarried individuals or challenge the assumption that marriage protects against dementia. Further research is needed to identify the specific pathways that lead to reduced dementia risk among unmarried older adults over time in a more representative sample, and to examine the association by considering the duration of post-marital life and the role of relationship factors (e.g., marital quality).