The interaction between activities of daily living and psychological resilience on all-cause mortality and cognitive impairment among Chinese older adults: A cohort study based on CLHLS

OBJECTIVES: To investigate the joint effects and interactions of psychological resilience (PR) and activities of daily living (ADL) on cognitive impairment and all-cause mortality. METHODS: Chinese older adults were recruited from the Chinese Longitudinal Healthy Longevity Survey. Cox proportional hazards regression and log-binomial regression were employed to estimate the associations between exposures and all-cause mortality and cognitive impairment (defined as MMSE score <18 or self-reported dementia). Interactions were test on the basis of multivariable regressions. RESULTS: Compared to participants with normal ADL and high PR (Group 1), participants with limited ADL and high PR (Group 3, HR = 2.105; 95 % CI: 1.656, 2.676) and those with limited ADL and low PR (Group 4, HR = 3.076; 95 % CI: 2.436, 3.884) showed significantly increased risks of all-cause mortality. Moreover, the synergistic interactions between ADL and PR for all-cause mortality were evidenced by relative excess risk due to interaction (RERI = 0.824; 95 % CI: 0.363, 1.286), attributable proportion due to interaction (AP = 0.268; 95 % CI: 0.121, 0.415) and synergy index (SI = 1.659; 95 % CI: 1.134, 2.426). Regarding cognitive impairment, compared to Group 1, Group 3 (RR = 1.662; 95 % CI: 1.073, 2.576) and Group 4 (RR = 2.138; 95 % CI: 1.399, 3.8) exhibited increased risks. Additionally, subgroup analysis showed additive interaction for cognitive impairment was significant only in males. CONCLUSIONS: Limited ADL and low PR jointly increase the risks of cognitive impairment and all-cause mortality in Chinese older adults, with a synergistic additive interaction observed for all-cause mortality.