High levels of total screen time in young Canadian children are associated with lower reading and math test scores in elementary school, new research suggested.

Screen behavior patterns are established during the early years of life, and the earliest screen encounters are habit-forming and could persist into later life, according to the study authors.

The prospective study of data from 2008 to 2023 from more than 5000 children showed that each additional hour of daily screen time was associated with roughly 10% lower odds of achieving a higher level in reading and math in elementary school.

“Given how prevalent screen use is among children today, the magnitude and persistence of these associations have important public health implications,” lead author Xuedi Li, epidemiologist, and principal investigator Catherine Birken, MD, pediatrician, both of The Hospital for Sick Children in Toronto, told Medscape Medical News.

“Healthcare providers such as pediatricians and family physicians play an important role in supporting families to create balanced routines that include sleep, physical activity, and play, especially before school entry when habits are forming,” they said.

The study was published online on October 10 in JAMA Network Open.

Screen Use Quality

Researchers studied data from healthy children aged 0-5 years participating in the TARGet Kids! primary care cohort in Ontario between July 2008 and June 2023. Participant data were linked to annual grades 3 and 6 provincial standardized academic achievement test results.

At each well-child visit, parents completed an age-specific standardized questionnaire that included sociodemographic information, child and parent physical and mental health, and health behaviors (eg, screen time, sleep, and physical activity).

A total of 3322 grade 3 children (mean age at test, 8.86 years) and 2084 grade 6 children (mean age at test, 11.86 years) with screen time data that had been collected before their standardized test data were included in the study. Screen time was measured at a single point, closest to the end of the study.

About half (51.6%) of the grade 3 children were male. About 4% reported African ethnicity, 58% European ethnicity, 22.8% multiethnic, and 7.2% South Asian ethnicity. About half overall (48.8%) reported a family income greater than CA$150,000 per year. Ethnicities and family income were similar among grade 6 children.

The mean screen time for grade 3 children was 89.28 min/d, and for grade 6 children, 98.33 min/d.

In grade 3, 55.9% of children were at the provincial standard for reading, 77.2% for writing, and 53.8% for math. In grade 6, 68.6% met the standard for reading, 60.9% for writing, and 49.3% for math.

Female students outperformed male students in reading and writing in both grades, with a higher percentage of female students meeting or exceeding the provincial standard. Math achievement was similar in male and female students in both grades.

“There may be many reasons for lower reading and math achievement,” Li and Birken acknowledged. “Although we adjusted for a broad range of sociodemographic and family factors, other unmeasured factors such as parental assistance with homework and classroom environments could also contribute.”

In adjusted models, each additional hour per day of total screen time was associated with 9%-10% lower odds of achieving a higher academic level in grade 3 reading (odds ratio [OR], 0.91), grade 3 math (OR, 0.91), and grade 6 math (OR, 0.90). There was insufficient evidence of associations with grade 3 writing and grade 6 reading and writing.

TV and digital media time were associated with lower achievement levels in grade 3 reading and math and grade 6 math, whereas video game use was associated with lower achievement in grade 3 reading (OR, 0.77).

Beyond screen time duration, “quality of screen use, meaning content and context, is very important,” Li and Birken said. “Currently, we rely on parent-report questionnaires: the most feasible method in large studies of young children. But there is a real need to develop innovative, objective tools to capture what children are watching and how screens are being used.”

This would require “a multilevel approach involving families, schools, healthcare providers, and communities, all supporting balanced screen use habits, offering health, movement, and learning-promoting activities that emphasize social and physical development,” they concluded.

Limitations to the study included its observational design, use of parent-reported questionnaires to measure child screen time, lack of data specific to social media use, and a study population that consisted mainly of urban children of higher socioeconomic status, which might limit the generalizability of the findings.

“Canada and the United States have similar screen time recommendations for children,” Li and Birken noted. “Because screens are deeply embedded in children’s lives, similar findings may be found in other settings. However, cross-country differences in education systems, digital access, and monitoring could influence the findings.”

‘Growing Concerns’

Commenting on the study for Medscape Medical News, Martin Guhn, PhD, associate professor at the Human Early Learning Partnership, University of British Columbia in Vancouver, said the findings are in line with a growing body of evidence showing that “a broad range of negative outcomes is related to screen time,” including health, learning, brain development, and social competence.

“We see that children who spent hours, daily, with screens are, on average, spending less time with parents and friends, sleep less, and are less engaged in other activities,” said Guhn, who was not involved in the study.

Regarding possible interventions, he said, “Health associations have recommendations for limiting screen time. Schools across the world increasingly ban cell phones and social media, either completely, or for certain age groups, or during specific times. And recently, Denmark announced a social media ban for children [under age 15 years].”

“All these reactions are in response to growing concerns around excessive screen time,” he said. “The common goal: to raise children in a way that they learn to use technology and screen time in healthy ways — the same way we try to raise children and youth to be responsible with any behaviors that could involve health risks.”

This work was supported by grants from the Canadian Institutes of Health Research and the Edwin S.H. Leong Centre for Healthy Children at the Hospital for Sick Children and the University of Toronto. Birken reported receiving grants from the Heart and Stroke Foundation of Canada, Physician Services, Inc., the Center for Addiction and Mental Health, and the Walmart Canada Regional Community Grant during the conduct of the study. Li and Guhn reported having no relevant financial relationships.

Marilynn Larkin, MA, is an award-winning medical writer and editor whose work has appeared in numerous publications, including Medscape Medical News and its sister publication MDedge, The Lancet (where she was a contributing editor), and Reuters Health.