Prospective self- and informant-personality associations with inflammation, health behaviors, and health indicators
Amanda J Wright, Sara J Weston, Sara Norton, Michaela Voss, Ryan Bogdan, Thomas F Oltmanns, Joshua J Jackson
*Health Psychology*
Abstract
Personality influences many aspects of the health process. It is unclear to what extent self- and informant-reports of the Big Five offer incremental validity for the prediction of inflammatory biomarkers and whether inflammation provides a unique pathway between personality and indicators of physical health, independent of health behaviors. Using data from older adults (N = 1,630) enrolled in the St. Louis Personality and Aging Network study, we tested whether self- and informant-reported Big Five traits show unique associations with inflammation (IL-6, CRP, TNF-alpha). Further, we tested whether inflammation and health behaviors indirectly link personality to health-related quality of life, body mass index, and chronic disease burden using longitudinal mediation in a structural equation modeling framework. Self-reports, informant-reports, and general trait factors of personality predicted future inflammatory biomarker levels. Additionally, all assessment methods of personality were associated with the indicators of physical health through biomarker and health behavior pathways. Effects were primarily found for conscientiousness and neuroticism; IL-6 and CRP were the biomarkers with the most indirect effects; and indirect paths overall emerged more frequently through health behaviors, but this varied by outcome. Self- and informant-reports provided unique predictive validity of inflammatory biomarkers. Findings highlight the benefits of using of multiple assessments of personality and the importance of examining multiple, distinct pathways by which personality might influence health to understand the mechanisms underlying this relationship more fully.
Why we asked
Personality is linked to health, and the usual explanation is behavior. Conscientious people exercise more and smoke less, and that adds up. Inflammation offers another route, because chronic inflammation is tied to heart disease and other problems, and traits could be related to it through the stress response. Nearly all earlier work on personality and inflammation relied on people describing themselves. We wondered whether the view of a spouse, relative or friend would add anything, and whether inflammation matters beyond health behaviors.
What we did
We used the St. Louis Personality and Aging Network study, which enrolled 1,630 adults aged 55 to 65 in 2007. Participants and an informant who knew them well (for half, a spouse or partner) rated the participant’s personality on the same questionnaire. About seven years later, we had blood samples for 791 participants, from which we measured three inflammatory markers (IL-6, CRP and TNF-alpha), along with a checklist of health behaviors. About ten years after baseline, we measured physical health-related quality of life, body mass index, and the number of chronic diseases. We separated what self-reports and informant reports have in common from what is unique to each with a bifactor model, and we tested indirect paths from personality through inflammation and through health behaviors.
What we found
Self-reports, informant reports, and the shared part of the two were each associated with inflammation years later, and the informant reports were not redundant with the self-reports. The associations were mostly for conscientiousness and neuroticism, and mostly for IL-6 and CRP. Indirect paths ran through inflammation and through health behaviors, and the two operated separately. Effects were small, which is typical for this literature, and small effects can still add up over decades.
What it means
Our measures were not repeated over time, so we cannot say which way the arrows run. Health behaviors or inflammation might shape how people see themselves, and our sample of St. Louis area adults may be healthier than the typical resident. Studies of personality and health should collect ratings from other people, and should include biological markers beside behaviors.
More than one view of personality helps explain health.