Association Between Psychological Resilience and Cognitive Function in Later Life: Effect Modification by Inflammatory Status

Abstract

Background: We aimed to examine the association between psychological resilience and cognitive function and investigate the role of acute inflammation as an effect modifier. Methods: Total 7,535 people from the Cardiovascular and Metabolic Disease Etiology Research Center (CMERC), aged ≥50, were included in the analysis. Stressful life events in the past 6 months were gauged by the Life Experience Survey, and current depression symptoms were analysed with the Beck Depression Inventory-II. Participants were categorised into four groups according to their past experience and depression status: ‘reference,’ ‘resilient,’ ‘reactive depression,’ and ‘vulnerable depression.’ Cognitive function was evaluated using the Mini-Mental State Examination (MMSE). The level of high-sensitivity C-reactive protein (hsCRP) and Interleukin-6 were measured from blood samples. A generalised linear regression was performed. Upon adjusting for socio-demographic factors, comorbidity, and lifestyle factors, the final model was stratified with the highest quartile of the hsCRP level by sex. Findings: Compared with the reference group, ‘resilient group’ showed higher MMSE, which was also significant in women (adj-β=0·280, p-value<0·001). ‘Vulnerable depression’ showed a significant lower MMSE (adj-β=-0·997, p-value 0·002) in especially men. This pattern seemed to be limited to the low hsCRP subgroup. Interpretation: Psychological resilience was associated with a lower likelihood of cognitive deficit in women. This pattern seemed to be modulated by inflammatory status. Funding Statement: This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science and ICT (2018R1C1B5083722), and the CMERC cohort study was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number HI13C0715). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: The Institutional Review Board of Yonsei University (YUIRB-4-2013-0661) approved the protocol of this study, and all participants provided written informed consents.