Marriage or singlehood? Surprising results reveal the social status that is most protective against dementia

A research team found that divorced or never-married older adults were less likely to develop dementia over an 18-year period than their married peers.

The findings suggest that not being married may not increase susceptibility to cognitive decline, contrary to prevailing beliefs in public health and aging research. 

Marriage is typically associated with better health outcomes and a longer lifespan, but evidence regarding the relationship between marital status and dementia risk remains inconsistent. Some studies have indicated a higher risk of dementia among unmarried individuals, while others have found no association or have shown conflicting results regarding divorce and widowhood. 

With the increasing number of divorced, widowed, or never-married older adults, concerns have emerged about these groups being at increased risk of developing dementia. Previous research has not systematically examined how marital status is associated with specific causes of dementia, or how factors such as gender, depression, or genetic predisposition may influence these relationships. 

In a study published in the journal Alzheimer's & Dementia, researchers from Florida State University College of Medicine and the University of Montpellier conducted an 18-year longitudinal study to understand whether marital status is associated with dementia risk in older adults. 

The study included more than 24,000 participants without dementia at the start of the study, enrolled from more than 42 Alzheimer's disease research centers in the United States through the National Coordinating Center.

Participants underwent annual clinical assessments by trained clinicians using standardized protocols to assess cognitive function and diagnose dementia or mild cognitive impairment. 

To analyze long-term risk, the researchers followed participants for up to 18.44 years. Marital status was initially categorized as married, widowed, divorced, or never married. 

The team analyzed dementia risk using a Cox proportional hazard model, with married people as the reference group. The models included demographic factors, physical and mental health, behavioral history, genetic risk factors, and diagnostic and registry variables. 

Compared with married people, divorced and never-married people showed a significantly lower risk of developing dementia during the study period. 

Dementia was diagnosed in 20.1% of the total sample, with the highest percentage among married people (21.9%) and widows (21.9%), while the percentage was much lower among divorced people (12.8%) and those who had never been married (12.4%). 

After adjusting for demographic, behavioral, and genetic factors, the researchers found that divorced and never-married individuals had a lower risk of developing dementia, with the risk reduced by 34% among divorced individuals and 40% among never-married individuals. 

The same pattern was observed in cases of Alzheimer's disease and Lewy body dementia, but no clear relationship was found with vascular dementia or frontotemporal degeneration. 

Divorced and never-married people were also less likely to progress from mild cognitive impairment to full-blown dementia. 

The results did not differ significantly across gender, age groups, or education levels. The researchers suggest that chronic stresses associated with marriage (such as family responsibilities or marital stress) may play a role in increasing the risk of dementia in married couples. 

Unmarried people may have diverse social support networks (friends, extended family) that provide cognitive protection without the pressures of a marital relationship. 

These findings challenge traditional assumptions that marriage is always beneficial for cognitive health, suggesting that being single or divorced may be protective factors against dementia in some cases.

However, the researchers stressed the need for further studies to understand the mechanisms behind this complex relationship.