In a groundbreaking study conducted by Florida State University College of Medicine and the University of Montpellier, a surprising conclusion emerged: older adults who were divorced or never married had a lower risk of developing dementia over an 18-year period compared to their married peers. This study challenges long-standing assumptions in public health and aging research, which have often suggested that being unmarried might increase one’s vulnerability to cognitive decline. The findings, published in the prestigious journal Alzheimer’s & Dementia, provide fresh insights into the complex relationship between marital status and dementia risk, offering a new perspective that could reshape how we view aging and cognitive health.
Rethinking the Relationship Between Marriage and Cognitive Health
For decades, marriage has been associated with numerous health benefits, including better mental health outcomes, longer life expectancy, and even lower risks for certain diseases. This has led to the belief that marriage, particularly in later life, serves as a protective factor against conditions like dementia. The notion was that the social and emotional support provided by a spouse could help buffer against cognitive decline. However, the evidence linking marital status to dementia risk has been inconsistent, with some studies showing a higher risk of dementia among unmarried individuals, while others found no significant difference or conflicting patterns for those who are divorced or widowed.
This new study, which followed over 24,000 participants from Alzheimer’s Disease Research Centers across the United States, challenges these assumptions. Researchers explored how marital status affected the risk of developing dementia, particularly Alzheimer’s disease and other cognitive disorders, over nearly two decades. The results were both unexpected and intriguing, offering a new lens through which to understand the relationship between marriage and mental health in older adults.
The Study: Methodology and Participants
The research involved a cohort of more than 24,000 older adults, all of whom were dementia-free at the start of the study. Participants were enrolled from more than 42 Alzheimer’s Disease Research Centers across the U.S. through the National Alzheimer’s Coordinating Center (NACC). Each participant underwent annual clinical evaluations conducted by trained clinicians, who used standardized protocols to assess cognitive function and track the progression of mild cognitive impairment (MCI) and dementia diagnoses.
The study aimed to investigate whether marital status was associated with the long-term risk of dementia, specifically over an 18-year period. Researchers categorized participants’ marital status at baseline as married, widowed, divorced, or never married. This allowed for an in-depth analysis of how each group fared in terms of dementia risk, while controlling for a range of factors that could influence cognitive health, including age, sex, physical health, behavioral history, genetics, and mental health.
Key Findings: Lower Risk of Dementia for Divorced and Never-Married Individuals
The study’s findings were striking. Over the 18-year follow-up period, divorced and never-married participants consistently showed a lower risk of developing dementia compared to their married counterparts. Among the total sample, 20.1% of participants developed dementia during the study period. However, the incidence of dementia was significantly lower in divorced (12.8%) and never-married (12.4%) individuals compared to those who were married (21.9%) or widowed (21.9%).
To assess the strength of these associations, the researchers used Cox proportional hazards regression models, with married individuals serving as the reference group. The results showed that both divorced and never-married participants had a markedly reduced risk of developing dementia. Specifically, divorced individuals had a 34% lower risk (hazard ratio [HR] = 0.66), while never-married individuals had a 40% lower risk (HR = 0.60) of developing dementia over the study period. For widowed individuals, the risk was also lower, but not as significantly, with a 27% reduction in risk (HR = 0.73).
Statistical Adjustments and Further Insights
What makes these findings particularly noteworthy is that the reduced risk for divorced and never-married individuals persisted even after adjusting for various factors that could influence dementia risk. These adjustments included physical and mental health conditions, behavioral patterns (such as smoking and alcohol consumption), genetic predispositions, and differences in clinical referrals. After controlling for these variables, the associations between marital status and dementia risk remained robust for divorced and never-married individuals.
However, the effect for widowed participants weakened after these adjustments, and the relationship between widowhood and dementia risk was no longer statistically significant. This suggests that the observed reduction in dementia risk among unmarried individuals, particularly those who are divorced or never married, cannot be fully explained by factors such as genetics or physical health alone.
Specific Dementia Subtypes: The Role of Alzheimer’s and Lewy Body Dementia
In addition to examining overall dementia risk, the researchers also analyzed the risk for specific subtypes of dementia. The results were revealing. Both divorced and never-married individuals showed a reduced risk for Alzheimer’s disease and Lewy body dementia. These findings align with the broader trend of lower dementia risk observed among unmarried adults. On the other hand, there were no consistent associations between marital status and the risk of vascular dementia or frontotemporal lobar degeneration, both of which have different underlying causes.
One particularly interesting aspect of the study was that divorced and never-married individuals were also less likely to progress from mild cognitive impairment (MCI) to full-blown dementia. MCI is often considered a precursor to dementia, and the fact that unmarried individuals showed a lower likelihood of progression suggests that marital status might play a role in slowing the cognitive decline that leads to dementia.
Subgroup Analysis: Demographic and Clinical Factors
The study also explored whether certain demographic or clinical factors influenced the relationship between marital status and dementia risk. The results were generally consistent across different subgroups, including age, sex, education level, and genetic risk factors. However, the risk patterns appeared slightly stronger among men, younger individuals, and those who had been referred to the study by health professionals, suggesting that these groups may be more sensitive to the protective effects of being unmarried.
Despite these variations, the overall conclusion remained clear: divorced and never-married individuals were less likely to develop dementia, even after considering a wide range of influencing factors. This points to the possibility that factors associated with being unmarried—such as greater independence or different social networks—may have a protective effect on cognitive health.
Implications for Public Health and Aging Research
The findings of this study have significant implications for public health and aging research. The traditional view that marriage offers protective benefits against dementia is called into question. Instead, the evidence suggests that being unmarried—whether divorced, widowed, or never married—may not be a risk factor for dementia and could, in fact, offer some degree of protection.
This challenges the long-held belief that social isolation or lack of a spouse puts individuals at higher risk for cognitive decline. Instead, it opens up new avenues for research into how marital status and social relationships interact with factors like mental health, genetics, and lifestyle choices to influence dementia risk.
Moreover, these findings could help inform interventions aimed at preventing or delaying dementia. Rather than focusing on marital status as a risk factor, future research may want to examine the specific aspects of being unmarried that contribute to cognitive resilience. For example, are there lifestyle factors or social behaviors that unmarried individuals engage in that help protect their brains? These questions could shape future strategies for dementia prevention.
Conclusion: Rewriting the Narrative on Marital Status and Dementia Risk
The study by Florida State University College of Medicine and the University of Montpellier challenges many of the assumptions about marriage and dementia risk that have prevailed in public health for decades. Contrary to conventional wisdom, being unmarried—particularly through divorce or never having been married—does not increase the risk of developing dementia. In fact, it may offer a surprising level of protection against cognitive decline.
As we continue to unravel the complexities of aging and cognitive health, it is clear that marital status is just one of many factors that contribute to an individual’s risk of dementia. This study serves as a reminder that aging is not a one-size-fits-all process, and factors such as social relationships, mental health, and lifestyle choices can have profound effects on the brain.
The findings from this study open the door for future research to explore how different life experiences—such as the decision to remain unmarried—affect long-term cognitive health. By challenging outdated beliefs and considering the full spectrum of factors that influence dementia risk, we can move closer to a more nuanced understanding of aging and cognitive decline. The next step is to dive deeper into the protective mechanisms at play for unmarried individuals, which may ultimately lead to better strategies for preventing dementia across all populations.
Reference: Selin Karakose et al, Marital status and risk of dementia over 18 years: Surprising findings from the National Alzheimer’s Coordinating Center, Alzheimer’s & Dementia (2025). DOI: 10.1002/alz.70072