The health effects of sedentary behavior, such as screen time, include adiposity & T2DM risk in adults. How does screen time affect children?
Young children who report more than 3 hours of daily screen time are at risk for markers for type 2 diabetes mellitus (T2DM), particularly insulin resistance, and for obesity, according to a new study.
“Our findings suggest that reducing screen time may be beneficial in reducing T2D risk factors, in both boys and girls and in different ethnic groups from an early age,” said the authors, led by Dr. Claire M. Nightingale, Population Health Research Institute, St. George’s, University of London.
Recommendations from the American Academy of Pediatrics (AAP) previously suggested that children should limit daily screen time to less than 2 hours. More recently, the AAP did not propose a time limit and instead suggested that limits should be placed on hours per day of media use, which is “a more pragmatic interpretation given the pervasive use of electronic devices,” the authors noted.
The health effects of activities that encourage sedentary behavior, such as time spent watching television and using computers or games consoles-together referred to as screen time-have been prospectively associated with adiposity and T2DM risk in adults.
Nightingale and colleagues1 conducted The Child Heart and Health Study in England, a cross-sectional survey of heart health among 4495 children aged 9 to 10 years who attended 200 primary schools. The children had fasting cardiometabolic risk marker assessments and anthropometry measurements, and they reported daily screen time. Physical activity was measured in a subset of 2031 children.
Overall, 4% of children reported no screen time, 37% reported an hour or less of daily screen time, 28% reported between 1 and 2 hours of screen time a day, 13% said they had between 2 and 3 hours of screen time a day, and 18% reported more than 3 hours a day.
Boys were more likely to engage in more than 3 hours of daily screen time (22%) than girls (14%). Black children (African-Caribbean) were also more likely to report more than 3 hours of daily screen time (23%) as compared with both white and South Asian children (16%).
Compared with children who had 1 hour or less of screen time daily, those who reported more than 3 hours had a 1.95 higher ponderal index (an indicator of weight in relation to height), 4.5% higher skinfold thickness, 3.3% higher fat mass index, 9.2% higher leptin level, and 10.5% higher insulin resistance.
Associations with insulin resistance remained after adjustment for adiposity, socioeconomic markers, and physical activity. There were no strong associations with glucose, hemoglobin A1c, physical activity, and cardiovascular risk markers.
The authors noted that the study was conducted from 2004 to 2007 and therefore does not take into account the wide use of more recently introduced electronic devices, such as electronic tablets and smartphones, which are also potentially related to sedentary behavior.
“This is particularly relevant, given rising levels of T2D, the early emergence of T2D risk and recent trends suggesting that screen-time–related activities are increasing in childhood and may pattern screen-related behaviors in later life,” they stated.
Reference: Nightingale CM, Rudnicka AR, Donin AS, et al. Screen time is associated with adiposity and insulin resistance in children. Arch Dis Child. Published online March 13, 2017. Accessed April 17, 2017.