Never married → Dementia
Higher never married increases dementia.
In a pooled analysis, lifelong single adults had a higher risk of dementia than married people, with a relative risk of 1.42.
Meta-analysis · Moderate · N=15
The two move together in observational data. Nobody has yet tested whether one causes the other.
Mechanism
The authors do not name a pathway for this link, so how it might work is not settled.
Caveats
The comparison is against married people, and the interval is fairly wide (1.07 to 1.90). The pooled studies cannot show that staying single leads to dementia. Differences in education, income, social contact and health could account for part of the gap. Widowed people also showed elevated risk in the same review, at a smaller size.
Effect
Risk ratio 1.42 (95% CI 1.07 to 1.9). Lifelong single adults had a relative risk of dementia of 1.42 (95% CI 1.07 to 1.90) compared with married people.
Nodes
Named confounders
Cite this page
What Causes What. “Never married → Dementia.” https://whatcauseswhat.org/edges/e-never-married-dementia (atlas updated 2026-10-18).
Papers
- Marriage and risk of dementia: systematic review and meta-analysis of observational studies.
A Sommerlad, J Ruegger, A Singh-Manoux, G Lewis, G Livingston · 2019 · Journal of neurology, neurosurgery, and psychiatry
adults compared with married people, 15 studies · Risk ratio 1.42 (95% CI 1.07 to 1.9)