This nationwide cohort study examined whether having a spouse with incident dementia raises one's own dementia risk, and whether that risk varies by sex, age, income, urbanicity, and number of children — using Taiwan's National Health Insurance Research Database (1998–2022) with 955,105 matched individuals.
Spousal dementia exposure significantly raised all-cause dementia risk: HR 1.74 (95% CI, 1.70–1.78) for women (+2.75 percentage points over 5 years) and HR 1.69 (95% CI, 1.64–1.73) for men (+3.49 percentage points over 5 years). Relative risk was higher at younger ages; absolute risk differences grew with age. Higher income and more children attenuated the association.
- Study population is limited to married individuals in Taiwan, limiting generalizability to other cultural or family structures. - Administrative claims data may underdiagnose dementia, especially mild cases. - Matching on income and urbanicity may not fully control for shared lifestyle, environmental, or genetic confounders within couples.
Clinicians should recognize that caregiving spouses of dementia patients are themselves at meaningfully elevated dementia risk — nearly 70–74% higher relative risk — and consider proactive cognitive screening and support for this group, particularly older adults and those with lower income or fewer social supports.
