A study published in JAMA Network Open in July 2026 indicates that when one spouse is diagnosed with dementia, the other partner's risk of developing the condition increases by approximately 70%. The research, which analyzed data from Taiwan's National Health Insurance Research Database covering nearly a million married individuals, found that the risk is about 74% for wives and 69% for husbands. This pattern was consistent across various types of dementia, including Alzheimer's disease and vascular dementia.
The study tracked spouses of individuals newly diagnosed with dementia from 1998 to 2022, comparing them to a matched group whose partners did not have a diagnosis. Among women, the five-year risk of developing dementia was about 6.5% for those with an affected spouse, compared to 3.7% for those without. For men, the figures were approximately 9.2% versus 5.75%.
Younger spouses, particularly those under 55, exhibited the highest relative increase in risk, despite older individuals having a higher overall prevalence of dementia. Factors such as lower income and fewer children were associated with greater absolute risk gaps, likely due to reduced caregiving support. The study suggests that the shared environment, lifestyle, and caregiving stress may contribute to the increased risk for spouses.
The findings prompt a reconsideration of how dementia is approached in families, advocating for more comprehensive support and monitoring for partners of individuals diagnosed with dementia.