Taiwan study finds spouse’s dementia raises partner’s risk by up to 74%

A large analysis of Taiwan’s National Health Insurance records examined nearly one million married adults between 1998 and 2022. Researchers identified more than 190,000 individuals whose spouse had been diagnosed with dementia and compared them with over 760,000 matched controls whose partners were dementia‑free.

The study found that having a spouse with dementia increased a partner’s relative risk of developing the disease by 74 % for women and 69 % for men. In absolute terms, about 6.5 % of women and 9.2 % of men with an affected partner were diagnosed over a five‑year period, compared with 3.7 % and 5.8 % respectively among those whose spouses were not affected.

Authors noted that the association persists after adjusting for age, income, residence, existing medical conditions and family size, suggesting that shared lifestyle, assortative pairing and the stress of caregiving may all contribute to the heightened risk.