High amounts of screen time begin as early as infancy

"Our results indicate that screen habits begin early," said Edwina Yeung, Ph.D., the study's senior author and an investigator in the Epidemiology Branch of NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). "This finding suggests that interventions to reduce screen time could have a better chance of success if introduced early."

NICHD researchers and their colleagues analyzed data from the Upstate KIDS Study, originally undertaken to follow the development of children conceived after infertility treatments and born in New York State from 2008 to 2010. Mothers of nearly 4,000 children who took part in the study responded to questions on their kids' media habits when they were 12, 18, 24, 30, and 36 months of age. They also responded to similar questions when the children were 7 and 8 years old. The study compiled additional demographic information on the mothers and children from birth records and other surveys.

The American Academy of Pediatrics recommends avoiding digital media exposure for children under 18 months of age, introducing children 18 to 24 months of age to screen media slowly, and limiting screen time to an hour a day for children from 2 to 5 years of age. In the current study, researchers found that 87% of the children had screen time exceeding these recommendations. However, while screen time increased throughout toddlerhood, by age 7 and 8, screen time fell to under 1.5 hours per day. The researchers believe this decrease relates to time consumed by school-related activities.

The study authors classified the children into two groups based on how much their average daily screen time increased from age 1 to age 3. The first group, 73% of the total, had the lowest increase, from an average of nearly 51 minutes a day to nearly an hour and 47 minutes a day. The second group, 27% of the total, had the highest increase, from nearly 37 minutes of screen time a day to about 4 hours a day. Higher levels of parental education were associated with lower odds of inclusion in the second group. In addition, girls were slightly less likely to be in the second group, compared to boys, while children of first-time mothers were more likely to be in the high-increase group.

The researchers also classified the children into percentiles based on their total daily screen time. Children were more likely to be in the 10th, or highest, percentile if their parents had only a high school diploma or equivalent (more than twice as likely) or were children of first-time mothers (almost twice as likely). Similarly, compared to single-born children, twins were more likely to belong to the highest screen time group. Compared to children in center-based care, children in home-based care, whether provided by a parent, babysitter or relative, were more than twice as likely to have high screen time.