Negative and positive affect as predictors of inflammation: Timing matters

Area of Science:

• Psychoneuroimmunology
• Affective Science
• Biomarkers of Inflammation

Background:

• Research on the link between affect (negative and positive affect, NA and PA) and peripheral inflammation is limited, especially concerning intensive longitudinal assessments.
• Previous studies often rely on retrospective questionnaires, which may not accurately capture the dynamic relationship between daily emotional states and inflammatory markers.
• Understanding this relationship is crucial for developing targeted interventions for inflammation-related conditions.

Purpose of the Study:

• To investigate how different indicators of NA and PA, measured via ecological momentary assessment (EMA) and recalled questionnaires, predict peripheral inflammation.
• To examine the predictive value of both aggregated and temporally proximal affect measures on C-reactive protein (CRP) and inflammatory cytokines.
• To explore potential moderators (e.g., gender, education) and temporal dynamics in the affect-inflammation relationship.

Main Methods:

• A community sample of 220 adults completed baseline questionnaires and EMA reports (5x/day for 14 days).
• Blood samples were collected post-EMA to measure plasma levels of CRP and seven inflammatory cytokines (IL-1β, IL-6, TNF-α, IL-8, IL-4, IL-10, IFN-γ).
• Statistical analyses controlled for covariates and examined associations between affect measures and inflammatory markers, including moderation and temporal proximity.

Main Results:

• Neither recalled nor aggregated 14-day EMA measures of NA or PA predicted CRP or the cytokine composite.
• Aggregated NA from the second week of EMA (more proximal to blood draw) was associated with the cytokine composite, but not CRP.
• Exploratory analyses indicated that the cytokine composite was associated with PA in week 2 for men only, and with recalled NA for those with lower education.

Conclusions:

• The temporal proximity of affect assessment to biological sampling appears critical for detecting associations with peripheral inflammation.
• Recent negative affect, particularly in the week preceding blood collection, shows a stronger link to inflammatory markers than long-term recall or broadly aggregated daily affect.
• Future research should prioritize fine-grained temporal analyses and consider individual differences to elucidate the complex interplay between affect and inflammation.