Antonio Terracciano from Florida State University and colleagues from the US and France conducted a cohort study and found that married people have an increased risk of developing dementia in old age. The analysis included data from the National Alzheimer's Disease Coordinating Center (NACC) on more than 24,000 people (average age 71.79 years). They were followed up to 18 years. The relationship between initial marital status and clinical diagnosis of dementia was tested using Cox regression. The results were published in the journal Alzheimer's & Dementia.
Compared with married individuals, the risk of developing dementia overall was significantly lower in widowed, divorced, and never-married individuals: the hazard ratios (HR) were 0.73, 0.66, and 0.60, respectively. Analysis by individual diagnoses revealed a similar correlation for Alzheimer's disease and Lewy body dementia, heterogeneous data for frontotemporal dementia, and no correlation with the risk of vascular dementia and mild cognitive impairment; all unmarried subgroups had a lower risk of progression from mild cognitive impairment to dementia. The trends were not significantly dependent on age, gender, education, genetic predisposition, or the presence of depression.