Sleep Habits and Susceptibility to Upper Respiratory Illness: the Moderating Role of Subjective Socioeconomic Status.

BACKGROUND: Sleep is a predictor of infectious illness that may depend on one's socioeconomic status (SES).

PURPOSE: This study aimed to investigate the moderating effects of objective and subjective SES on sleep-clinical cold risk link and test whether nasal inflammation serves as a plausible biological pathway.

METHODS: This study combined data (n = 732) from three viral challenge studies. Measures of self-reported sleep and objective and subjective measures of SES were obtained. Participants were quarantined and administrated rhinovirus (RV) or influenza virus and monitored over 5 (RV) or 6 (influenza) days for the development of a cold. Symptom severity, including mucus production and nasal clearance time, and levels of nasal cytokines (interleukin (IL)-6 and IL-1β) were measured prior to administration and each day during the quarantined period.

RESULTS: Subjective SES, but not objective SES, moderated associations between shorter sleep duration and increased likelihood of a clinical cold. Compared to ≥8-hour sleepers, ≤6-hour sleepers with low subjective SES were at increased risk for developing a cold (OR = 2.57, 95% CI 1.10-6.02). There was no association between sleep duration and colds in high subjective SES participants. Among infected individuals who reported low subjective SES, shorter sleep duration was associated with greater mucus production. There was no evidence that markers of nasal inflammation mediated the link between sleep duration and cold susceptibility among those reporting low subjective SES.

CONCLUSION: Subjective SES may reflect an important social factor for understanding vulnerability to and protection against infectious illness among short sleepers.