Jan. 28 (UPI) -- Children who spend more time looking at tablets or television screens as infants are likely to be less physically active as they enter school age, a new study has found.
In an analysis involving more than 500 children from Singapore published Tuesday in the journal The Lancet Child and Adolescent Health, researchers concluded that children between age two and three who spend more than three hours a day "viewing screens" were likely to spend significantly more time sitting, or at least at rest, by the time they reached five years of age.
"Our findings support public health efforts to reduce screen viewing time in young children and suggest further research into the long term effects of screen viewing on movement behaviors is needed," co-author Bozhi Chen, of the Saw Swee Hock School of Public Health, National University of Singapore, said in a press release.
She added that she and her colleagues believe that the negative impact of early-life screen time on movement behaviors in later childhood highlights the importance of strategies to limit screen use during a child's formative years.
Excessive screen time in childhood has been linked with a wide range of health problems, including increased risk for obesity and reduced cognitive development.
Efforts to investigate this relationship have had mixed results, with most studies focusing on school-aged children and adolescents. Researchers have suggested that one way screen time may influence health is by effectively replacing time spent doing something else, including physical activity, sleep, playing with toys or reading.
Guidelines from the World Health Organization recommend parents limit screen time for children to one hour per day or less among those between two and five years of age, suggesting that this may promote healthier behaviors in later life. The authors of the new study say, however, that theirs is the first to look at the effects of early-life screen use on daily activity in pre-school children.
In the first of two assessments as part of the study, parents were asked to report how much time their two- and three-year-old children spent, on average, either watching TV or playing video games using a computer or a handheld device, such as a cellphone or tablet.
For the second assessment, conducted when the children enrolled in the study reached age five, the young participants wore an activity tracker continuously for seven days to monitor their sleep, sedentary behavior and physical activity levels.
In all, the authors found that children in the study spent an average of 2.5 hours a day watching screens at two to three years of age, with only a small proportion of them meeting WHO recommendations of one hour per day or less. TV was the most commonly used device and was associated with the longest viewing times.
Children between two and three years of age who spent three or more hours a day viewing screens on TV, computers or handheld devices spent an average of 40 minutes more time sitting down each day when they reached five years of age than those who had used screens for less than an hour a day at the younger age.
Overall, higher screen use in infancy was associated with around 30 minutes less light physical activity each day, and around 10 minutes less moderate to vigorous activity each day, regardlesss of screen type.
In a linked commentary, Dorothea Dumuid, of the University of South Australia, who was not involved in the screen time study, argued that the findings do not provide evidence of a causal link between screen time and reduced physical activity.
"In this rapidly evolving digital age, children's screen use is a key concern for parents and medical bodies," Dumuid wrote. "Guidelines to limit screen time have been released by many governments and WHO, however, screens offer digital and social connectedness and educational opportunities. Future research is needed to assess the influence of media content, to determine optimum durations of screen time in the context of 24-hour time use, and to explore causal pathways."