Associations between sleep duration trajectories from adolescence to early adulthood and working memory, schooling and income: a prospective birth cohort study from Brazil.

ABSTRACT

OBJECTIVE: This study aimed to evaluate the relationship between sleep duration trajectories from adolescence to early adulthood and working memory, schooling and income at 22 years in the Pelotas 1993 Birth Cohort. METHODS: Sleep duration was self-reported at ages 11, 18 and 22. Sleep trajectories were identified using finite mixture models. Schooling was recorded as the number of completed years of education. Working memory was evaluated using The Digit Span test and income was recorded for who reported have a job and received a payment for this in the previous month. All analyses were stratified by sex. RESULTS: We used crude and adjusted (for demographic, health and behavior characteristics measured at perinatal and 11-years) linear or quantile regression analyses. A total of 2915 individuals were included. Three trajectories for males were used "increase and maintenance" (3.4%), "fast reduction and maintenance" (45.0%) and "constant reduction" (51.6%). For females, we used the trajectories "increase and decrease" (2.4%), "fast reduction and maintenance" (25.6%) and "constant reduction" (72.0%). Males from "increase and maintenance" and females from "increase and decrease" trajectories scored, on average, 1.6 and 1.8 points lower, respectively, in working memory test. They presented a median of 1.4 and 2.6 fewer schooling years, respectively, compared to individuals from the "fast reduction and maintenance" trajectory. Regarding income, no significant association was observed. CONCLUSION: Sleep duration during adolescence could affect cognitive and educational outcomes in early adulthood. Individuals who presented the expected sleep trajectory (decrease of sleep duration across adolescence) presented better outcomes.