Spouse's functional disability and mortality: The Ohsaki Cohort 2006 Study

Aim: Caregiver burden is known to negatively affect a partner's health. Given the important role of physical and mental stress in mortality, a higher caregiver burden might be associated with an increased incidence of fatal events. However, previous studies of the effects of the partner's caregiving on mortality have shown inconsistent results. Thus, the purpose of the present longitudinal study was to determine if there is an association between a spouse's functional disability and mortality in the older Japanese population. Methods: A baseline survey was carried out with 7598 participants in 2006. Information on the date of functional disability, death or emigration was retrieved from the Ohsaki City government. Functional disability was defined as receiving a certification for long-term care insurance in Japan. After a follow-up period of a maximum of 87 months, 1316 of the participants died and Cox regression analysis with adjustment for confounding factors was used to assess mortality after the incidence of functional disability in a spouse. Results: The multivariate adjusted hazard ratio for mortality was 1.78 (95% confidence interval 1.52–2.08, P < 0.01) in those whose spouses had functional disabilities compared with those with spouses who did not have functional disabilities. The mortality was consistently higher, irrespective of age group or sex. Conclusions: These results imply that caregiver burden might increase stress responses and lead to increased mortality; therefore, enhancement of support systems, including long-term care, housing and livelihood support services, for those with disability and their spouses might be important for preventing deaths. Geriatr Gerontol Int 2019; 19: 774–779.