Affective reactivity to daily stressors is associated with elevated inflammation

Abstract

Objective: Inflammation increases the risk of chronic diseases, but the links between emotional responses to daily events and inflammation are unknown. We examined individual differences in affective reactivity to daily stressors (i.e., changes in positive and negative affect in response to stressors) as predictors of inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP).

Methods: A cross-sectional sample of 872 adults from the National Study of Daily Experiences (substudy of Midlife in the United States II) reported daily stressors and affect during telephone interviews for 8 days. Blood samples were obtained at a separate clinic visit and assayed for inflammatory markers. Multilevel models estimated trait affective reactivity slopes for each participant, which were inputted into regression models to predict inflammation.

Results: People who experienced greater decreases in positive affect on days when stressors occurred (i.e., positive affect reactivity) had elevated log IL-6, independent of demographic, physical, psychological, and behavioral factors (B = 1.12, SE = 0.45, p = .01). Heightened negative affect reactivity was associated with higher log CRP among women (p = .03) but not men (p = .57); health behaviors accounted for this association in women.

Conclusions: Adults who fail to maintain positive affect when faced with minor stressors in everyday life appear to have elevated levels of IL-6, a marker of inflammation. Women who experience increased negative affect when faced with minor stressors may be at particular risk of elevated inflammation. These findings add to growing evidence regarding the health implications of affective reactivity to daily stressors.

Figure 1. NA Reactivity x Gender interaction for CRP (p = 0.025 in fully-adjusted model)

For illustrative purposes, low and high NA reactivity are depicted as ±1 SD from the mean; error bars are 95% confidence intervals. Women who experienced greater increases in NA in response to daily stressors tended to have higher levels of CRP, compared to women with less NA reactivity (p = 0.03 for simple slope). NA reactivity was not related to CRP among men (p = 0.57 for simple slope).