Loneliness and Diurnal Salivary Cortisol in Emerging Adults

Julian Lai,Yun Lam,Karsten Berning,Daryl Lee,Monique Leung

doi:10.3390/ijms19071944

Julian Lai, Yun Lam + Show 3 more

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https://doi.org/10.3390/ijms19071944

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Abstract

This study aimed to examine the relationship between trait loneliness and diurnal rhythms of salivary cortisol. Fifty-One Chinese undergraduates provided six saliva samples on a weekday at immediately, 0.5, 3, 6, and 12 h after waking, and at bedtime. Saliva collection times were monitored using electronic devices (MEMS TrackCaps). Participants were also administered a questionnaire consisting of scales measuring, trait loneliness, depression, and demographics. Relationships between loneliness and the cortisol awakening response (CAR), diurnal slope (DS), and area under the curve with respect to ground (AUCG) were examined using multiple regression analyses. Results showed that a higher loneliness score was associated with an attenuated CAR, a large AUCG, and a steeper DS, with the effects of compliance, waking time, and depression being controlled. As a blunted CAR and a higher diurnal cortisol level have been shown to be associated with poorer health in prior studies, increased attention to the mechanisms translating loneliness into disease endpoints via elevated cortisol is warranted.

Highlights

Loneliness [1] has emerged as an important determinant of the physiological processes of stress and increased morbidity in recent research [2,3,4]
To examine whether a significant cortisol awakening response (CAR) or diurnal slope in cortisol was demonstrated in the present sample or not, one-way ANOVAs with repeated measures were conducted
Using electronic devices to monitor sampling times objectively, we have shown that higher loneliness scores were associated with increased cortisol secretion and an attenuated CAR in emerging adults

Summary

Introduction

Loneliness (or perceived social isolation) [1] has emerged as an important determinant of the physiological processes of stress and increased morbidity in recent research [2,3,4]. As an extensively researched biomarker of health, cortisol has been studied in relation to loneliness in recent years across different age groups (e.g., [5,6]). Dysregulation in the secretion or diurnal rhythm of cortisol has been shown to be detrimental to both physical and mental health [7,8]. There is evidence suggesting that the association between loneliness and increased morbidity is mediated by a potentiation of pro-inflammatory cytokines (e.g., [9,10,11]) possibly induced by chronically elevated cortisol (e.g., [12,13]). Glucocorticoid resistance may lead to elevated cortisol and excessive inflammation having significant implications for a variety of disease, as well as behavioral outcomes

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