Spouses' Individual and Shared Cumulative Risk: Implications for Functional Health and Longevity in Older Adulthood

Multisystem biological risk, a marker of physiological dysregulation, accumulates over time in response to exposure and adaptation to chronic stress. Spousal concordance in health and health behaviors indicates potential for shared risk to accumulate within couples. This study examined spouses' shared multisystem biological risk as a modifier of individual risk and predictor of future functional limitations and mortality.

Biomarkers and physical measures from 3,856 heterosexual couples (77%White, 31% college degree) were collected from the 2008/2010 waves of the Health and Retirement Study to construct individual and shared frailty, cardiometabolic, and total risk indices and predict functional limitations and survival at 2016/2018.

Multilevel Poisson and logistic regressions showed couples' cumulative shared frailty, cardiometabolic, and total risk to be associated with the number of functional limitations and survival status at follow-up. Spouses' shared cardiometabolic and total risks attenuated the effects of respective individual risks. Results were partially explained by partner selection and health experiences. Predicted probabilities were compared to gender-stratified models. The Receiver Operating Characteristic curve showed models of shared risk to have greater predictive power.

The findings from this study indicate that the cost of adaptation manifests not only in individuals, but also through an additional pathway that is co-constructed and shared by spouses. These findings underscore the critical role of shared context between individuals and their spouses in the treatment process.