The Association Between Loneliness and Inflammation: Findings From an Older Adult Sample.

Karina Van Bogart,Jennifer E Graham-Engeland,Martin J Sliwinski,Erik L Knight,Christopher G Engeland,Karra D Harrington,Ruixue Zhaoyang,Stacey B Scott

doi:10.3389/fnbeh.2021.801746

Abstract

Loneliness has been linked to poor mental and physical health outcomes. Past research suggests that inflammation is a potential pathway linking loneliness and health, but little is known about how loneliness assessed in daily life links with inflammation, or about linkages between loneliness and inflammation among older adults specifically. As part of a larger investigation, we examined the cross-sectional associations between loneliness and a panel of both basal and LPS-stimulated inflammatory markers. Participants were 222 socioeconomically and racially diverse older adults (aged 70–90 years; 38% Black; 13% Hispanic) systematically recruited from the Bronx, NY. Loneliness was measured in two ways, with a retrospective trait measure (the UCLA Three Item Loneliness Scale) and an aggregated momentary measure assessed via ecological momentary assessment (EMA) across 14 days. Inflammatory markers included both basal levels of C-reactive protein (CRP) and cytokines (IL-1β, IL-4, IL-6, IL-8, IL-10, TNF-α) and LPS-stimulated levels of the same cytokines. Multiple regression analyses controlled for age, body-mass index, race, and depressive symptoms. Moderation by gender and race were also explored. Both higher trait loneliness and aggregated momentary measures of loneliness were associated with higher levels of CRP (β = 0.16, p = 0.02; β = 0.15, p = 0.03, respectively). There were no significant associations between loneliness and basal or stimulated cytokines and neither gender nor race were significant moderators. Results extend prior research linking loneliness with systemic inflammation in several ways, including by examining this connection among a sample of older adults and using a measure of aggregated momentary loneliness.

Highlights

IntroductionHumans are social beings and possess a fundamental need to feel connected to others
Based on previous research illustrating gender differences related to health outcomes, we hypothesized that the link between loneliness and inflammation would be stronger among women and we examined race as a moderator on an exploratory basis
Among a racially/ethnically diverse sample of older adults living in the Bronx, New York, both higher trait loneliness and aggregated momentary measures of loneliness were associated with higher levels of C-reactive protein (CRP), controlling for age, race, body mass index (BMI), and depressive symptoms

Summary

Introduction

Humans are social beings and possess a fundamental need to feel connected to others. When this need is not met, feelings of loneliness arise. Loneliness is defined as a subjective, unpleasant psychological state of feeling alone that stems from a discrepancy between desired and actual social relationships (Peplau and Perlman, 1982). Loneliness often predicts health separately from objective measures of social isolation (Cacioppo et al, 2015; O’Súilleabháin et al, 2019), highlighting the importance of the subjective experience of loneliness. While the mechanisms underlying the link between loneliness and health are not fully understood, growing evidence suggests that inflammation may play a significant role in this relationship (Hawkley and Cacioppo, 2003; Hawkley et al, 2007; Kiecolt-Glaser et al, 2010; Cacioppo and Cacioppo, 2018)

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