Loneliness Is Associated with Sleep Fragmentation in a Communal Society

Study Objective: Loneliness has been shown to predict poor health. One hypothesized mechanism is that lonely individuals do not sleep as well as individuals who feel more connected to others. Our goal was to test whether loneliness is associated with sleep fragmentation or sleep duration. Design: Cross-sectional study. Setting: Members of a traditional, communal, agrarian society living in South Dakota. Participants: Ninety-five participants (mean age 39.8 years, 55% female) who were >= 19 years of age at the study's inception. Interventions: Not applicable. Measurements and Results: We conducted interviews querying loneliness, depression, anxiety, and stress, as well as subjective sleep quality and daytime sleepiness. Study participants wore a wrist actigraph for one week to measure objective sleep properties; the two studied here were sleep fragmentation and sleep duration. Higher loneliness scores were associated with significantly higher levels of sleep fragmentation (beta = 0.073, t = 2.55, P = 0.01), controlling for age, sex, body mass index, risk of sleep apnea, and negative affect (a factor comprising symptoms of depression and anxiety, and perceived stress). Loneliness was not associated with sleep duration or with either subjective sleep measure. Conclusions: Loneliness was a significant predictor of sleep fragmentation. Humans' social nature may partly be manifest through our dependence on feeling secure in our social environment to sleep well.