Original ArticleCorrelates of self-reported weekday sleep duration in adolescents: the 18-year follow-up of the 1993 Pelotas (Brazil) Birth Cohort Study

•This study is based on data from a well-described, high-quality birth cohort study (follow-up rate 81.3% at 18 years of age).•Early and contemporaneous factors associated with sleep duration in adolescents are examined.•Socio-demographic factors are more important than early biological or maternal behavioral characteristics in determining sleep duration in adolescence.

ObjectiveTo investigate factors associated with sleep duration in adolescence.MethodsData are from the 1993 Pelotas Birth Cohort Study of 5249 live births. Of these individuals, 4563 were located for follow-up at 18 years of age, and 4106 agreed to be interviewed (follow-up rate 81.3%). Sleep duration was continuously assessed by survey as hours per weekday. Additional covariates were collected during the perinatal period and at the 11- and 18-year follow-ups. Linear regression models were used to estimate associations between sleep duration and its hypothesized influences. All analyses were sex-stratified.ResultsThe average sleep duration among participants was 8.4 hours (standard deviation 1.9). Longer sleep duration at 18 years of age was associated with the following perinatal factors: low maternal schooling, low family income, maternal black skin color, and low birth weight; and with the following factors measured at 18 years of age: being out of school, low achieved schooling, low family income, absence of depressive symptoms, and high screen time.ConclusionSocial and demographic variables may play an important role in determining adolescents' sleep duration, but the nature of these relationships in Brazil may differ from those observed in higher-income contexts.