Daily positive events and inflammation: Findings from the National Study of Daily Experiences

Abstract

Background Inflammation is implicated in the development of chronic diseases and increases the risk of mortality. People who experience more daily stressors than others have higher levels of inflammation, but it is unknown whether daily positive events are linked to inflammation. Objective To examine the association of daily positive events with 3 inflammatory markers, interleukin-6 (IL-6), C-reactive protein (CRP), and fibrinogen. Method A cross-sectional sample of 969 adults aged 35–86 from the Midlife in the United States Study completed telephone interviews for 8 consecutive evenings. Participants reported positive experiences that occurred over the past 24 hours. Blood samples were obtained at a separate clinic visit and later assayed for inflammatory markers. Regression analyses evaluated the frequency of daily positive events (defined as the percent of study days with at least 1 positive event) as a predictor of each inflammatory marker. Covariates included information on demographics, physical health, depressive symptoms, dispositional and behavioral factors, and daily positive and negative affect. Results On average, participants experienced positive events on 73% of days (SD = 27%). The frequency of daily positive events was associated with lower IL-6 (p < 0.001) and CRP (p = 0.02) in the overall sample, and lower fibrinogen among women (p = 0.01). The association remained for IL-6 in the fully adjusted model, but was no longer significant for CRP and fibrinogen after controlling for household income and race. Effects were more pronounced for participants in the lowest quartile of positive event frequency than for those in the top 3 quartiles, suggesting that lack of positivity in daily life may be particularly consequential for inflammation. Furthermore, interpersonal positive events were more predictive of lower IL-6 overall and lower fibrinogen in women than non-interpersonal positive events. Conclusion Daily positive events may serve a protective role against inflammation.

Daily social interactions, close relationships, and systemic inflammation in two samples: Healthy middle-aged and older adults

“…The association between frequency of positive interactions and inflammation is consistent with the growing literature supporting an association of positive affect and daily positive events with circulating inflammatory markers (Stellar et al, 2015;Sin et al, 2015). For example, Sin and colleagues (2015) reported that positive interpersonal events were associated with lower IL-6 and fibrinogen in women.…”

Daily positive events and diurnal cortisol rhythms: Examination of between-person differences and within-person variation

“…During nightly telephone interviews, participants were asked whether any of these five positive events had occurred in the past 24 hours: (a) positive interpersonal interaction, (b) positive experience at work, school, or at a volunteer position, (c) positive experience at home, (d) network positive event (i.e., positive event experienced by a close friend or relative), and (e) any other positive event (Charles et al, 2010; Sin et al, 2015). For example, positive interpersonal interactions were assessed with the question, “Did you have an interaction with someone that most people would consider particularly positive (for example, sharing a good laugh with someone, or having a good conversation) since we spoke yesterday?” Participants were also asked to report what time the events happened.…”

“…Positive events were entered as a dichotomous variable (1 = positive event day, 0 = no positive event that day) when examined as a within-person predictor. 1 As a between-person predictor, the frequency of positive events was computed as the percent of study days during which at least one positive event occurred (Seltzer et al, 2009; Sin et al, 2015). …”

“…Daily positive events are favorable or desirable events, such as having a positive social interaction or spending time in nature, that are external to a person’s emotional states and reflect transactions with the environment (Sin et al, 2015; Zautra et al, 2005). People who experience more frequent daily positive events tend to have higher positive affect (Zautra et al, 2005), better health behaviors (Sin et al, 2015, 2017; Tomfohr et al, 2011), lower body mass index (Sin et al, 2015), and lower levels of inflammation (Bajaj et al, 2016; Jain et al, 2007; Sin et al, 2015), compared to those who report fewer daily positive events.…”

“…People who experience more frequent daily positive events tend to have higher positive affect (Zautra et al, 2005), better health behaviors (Sin et al, 2015, 2017; Tomfohr et al, 2011), lower body mass index (Sin et al, 2015), and lower levels of inflammation (Bajaj et al, 2016; Jain et al, 2007; Sin et al, 2015), compared to those who report fewer daily positive events. The previously observed links between daily positive events and reduced inflammation may be due, at least in part, to normative HPA axis activity and less glucocorticoid resistance (Miller et al, 2002; Rohleder, 2012).…”