Screen time drives kids to move less

Toddlers with longer screen time are less active, spending more time engaging in sedentary behaviour and shorter time performing light and moderate-to-vigorous physical activity (MVPA) in later childhood, according to a Singapore study.

Such findings indicate that screen-based sedentary behaviour displacing physical activity could occur as early as age 2–3 years, as the investigators pointed out.

“Considering the substantial amount of screen viewing time at ages 2–3 years and its negative impact on movement behaviours and health later in life, strategies to reduce screen viewing time during the early years are needed to address this important public health threat,” they said.

The analysis included 552 children from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) study. Those who clocked longer hours of screen viewing at age 2–3 years had shorter hours of sleep (p=0.008). They also were moving less at age 5.5 years, doing less light physical activity (p<0.0001) and MVPA (p<0.0001). [Lancet Child Adolesc Health 2020;4:201-209]

Spending ≥3 hours versus ≤1 hour per day sitting in front of screen devices, such as televisions, computers, or handheld devices, at age 2–3 years was associated longer time being stationary (480.0 vs 439.8 minutes per day) and shorter time doing light physical activity (356.2 vs 384.6 minutes per day), and MVPA (63.4 vs 76.2 minutes per day) at age 5.5 years. Time spent sleeping, on the other hand, was not significantly different (540.4 vs 539.5 minutes per day).

“In the present study, children spent on average more than 2 hours per day watching screen devices at 2–3 years, and only a small proportion of [the population] met the World Health Organization recommendations of 1 hour per day or less of screen viewing time,” the investigators said.

“Television was the most commonly used screen device and was associated with the longest viewing time. Additionally, children spent more than 30 minutes per day using handheld devices,” they added.

These data are consistent with previous findings from the same GUSTO cohort and other reports among children aged <3 years. Taken together, the evidence indicates that even small amounts of daily screen viewing take a toll on health behaviours, the investigators noted. [Int J Behav Nutr Phys Act 2019;16:70; Int J Obes 2019;43:1334-1343; BMC Public Health 2019;19:59]

According to previous research done in the GUSTO cohort, as few as 5.5 percent of Singaporean children around 5 years of age met integrated 24-Hour Movement Guidelines, similar to other Asian countries. The investigators expressed concern regarding such a low adherence to the integrated movement guidelines, because adherence to the recommendations for all movement behaviours is essential in lowering the risk of obesity and other noncommunicable diseases as compared with adhering to only one or none of the individual guidelines. [Prev Med Rep 2017;8:279-285]

“Our analysis addresses an important research gap and establishes a platform for research to further assess the effect of content type, timing, and parental co-use of media with their children on unfavourable movement behaviours,” they said.

The investigators called for additional investigation into the potential longitudinal effects of screen viewing on movement behaviours in order to confirm and extend the present findings.