However, few sleep studies utilise standard measures of both classroom behaviour and academic achievement.

The findings of the study were published in a Child Development article, written by researchers at the NYU Grossman School of Medicine, Harvard Medical School, and the University of Texas at Austin. The new longitudinal study examined the relationship between sleep, classroom behaviour, and academic achievement scores among primarily Black children growing up in historically disinvested neighbourhoods.

Disinvested refers to neighbourhoods in which public and private funding, city services, or other necessary resources have been denied or withheld, and which are often segregated along racial and economic lines as a result. The findings showed that sleep is related to observed classroom behaviour and may predict future academic achievement. According to the study, higher teacher-reported child sleepiness was associated with lower observed adaptive behaviours (defined as active engagement in learning in the classroom), and higher classroom behaviour problems in first grade.

Higher teacher-reported child sleepiness also predicted lower academic achievement as assessed one year later, in second grade. Parent-reported bedtime resistance and disordered breathing also predicted lower achievement in second grade. "Our study, the first to examine the ways in which sleep is related to observed engagement in learning and academic test scores among primarily Black children growing up in disinvested neighborhoods, highlights the importance of educating both parents and teachers about fostering positive sleep habits in young children for their school success," said Alexandra Ursache, assistant professor in the department of population health at NYU Grossman School of Medicine.

Ursache added, "The study indicates that encouraging teachers to share their observations of children's sleepiness with parents, in a collaborative and culturally-affirming manner could help make them aware of its interference with learning." The study included 572 predominantly Black first-grade girls and boys with over half coming from immigrant families. The children came from 10 schools located in historically disinvested neighborhoods in New York City. Children in first and second grade (approximately ages 6 and 7), were assessed on: 1. Sleep health and sleep disorder symptoms: Parents used a questionnaire to report on their children's bedtime resistance, sleep duration, disordered breathing, daytime sleepiness, and sleep onset delay. Teachers reported on their students' daytime sleepiness. 2. Classroom behaviour (adaptive and problem behaviours): Observers from the research team used a coding system to assess students' adaptive behaviours (non-verbal actively engaged learning such as listening, nodding, sitting up, working on an assigned task) and problem behaviours (behavioural or emotional problems).

3. Academic achievement: A standardised academic achievement assessment was administered by trained research assistants to assess reading, math and writing ability in second grade. "Sleep is an essential component of healthy development for children, and children of colour are at elevated risk for poor sleep health and undetected sleep disorders," said Alicia Chung, assistant professor in the department of population health at NYU Grossman School of Medicine. "This can set the stage for sleepiness in school, increased problem behaviour, decreased engagement in learning activities and lower academic achievement."

"The findings raise the possibility that developing a sleep health curriculum may help engage teachers and parents to promote sleep health," said Rebecca Robbins, instructor in medicine at Harvard Medical School. The authors acknowledge that the measures of sleep used in this study were reported by parents and teachers rather than objective, standardised assessments (for example, collected through activity monitors).

The authors also recognise that the measures provided by teachers and parents may include inherent bias involving Black children or African American children being incorrectly rated as sleepy. Although the authors controlled for several important covariates and examined longitudinal relations with academic achievement, they cannot make strong causal claims about the relations between sleep health and classroom behaviour or achievement without a research design that intentionally manipulates sleep behaviour, for example by randomly selecting some families to participate in an intervention to promote sleep health.

This work may also not be generalised to Latinx children or other populations of children of colour.