Sociodemographic and behavioural correlates of social jetlag in Australian adults: results from the 2016 National Sleep Health Foundation Study.

Social jetlag is a term used to describe misalignment between biological and social time. Measured as the difference in sleep midpoints between work and free days, social jetlag has been associated with unhealthy lifestyle behaviours and adverse health outcomes. This study aimed to identify the prevalence of social jetlag, and its sociodemographic and behavioural correlates in 837 respondents who completed the Sleep Health Foundation Australia 2016 online survey. Binomial logistic regression models determined associations between social jetlag and self-reported lifestyle and work outcomes, excluding night, evening or rotating shift workers. One third (31.1%) of respondents experienced >1h of social jetlag. In analyses adjusted for sociodemographic variables associated with social jetlag (age, marital status, work status and metropolitan living plus the significant interaction term for age by metro living), social jetlag was associated with longer sleep duration on free days (OR = 2.8, CI = 1.9-4.1), evening preference (OR = 2.0, CI = 1.4-2.4), often staying up later than planned on work days (OR 1.9, CI = 1.3-2.9), and having a computer (OR = 1.7, CI = 1.2-2.4) or phone (OR = 1.6, CI = 1.1-2.4) in the bedroom and internet use in the hour before bed (OR = 1.7, CI 1.2-2.5). Almost twice as many working respondents with social jetlag reported going to work when they should have taken sick leave due to their state of health (OR = 1.9, CI = 1.3-3.0). In conclusion, social jetlag is prevalent in the Australian community and associated with bedtime technology use. Work attendance when in poor health is cause for concern in Australian day workers and requires further investigation.