Screen time linked to higher body fat in primary school children, study finds
Excessive screen use is associated with higher levels of body fat and less favourable metabolic markers in primary school children, according to new research, with findings also suggesting that good cardiorespiratory fitness may help offset some of these effects.
The study, published in Frontiers in Endocrinology, examined the relationship between screen time, adiposity and metabolic health in school-aged children. Childhood obesity remains a major public health concern, with prevalence continuing to rise worldwide. Between 2000 and 2023, the prevalence of obesity and overweight among children and adolescents was estimated at 8.5 per cent and 14.8 per cent, respectively.
Sedentary behaviour is recognised as a key contributor to unhealthy weight gain, with screen time one of the most common sedentary activities among children. Although international guidelines recommend limiting recreational screen time to no more than two hours per day, many children exceed this threshold. Prolonged screen exposure has previously been linked to physical inactivity, unhealthy eating patterns, reduced sleep quality and increased adiposity.
Researchers from the First Affiliated Hospital of Ningbo University, China, analysed data from 1,286 third-grade pupils across six schools. Cardiorespiratory fitness was assessed using the 20-metre shuttle run test, while information on screen time, physical activity and diet quality was collected using questionnaires. Participants also underwent anthropometric assessments, body composition analysis, blood pressure measurement and fasting blood tests.
After adjusting for age, sex, maternal education, physical activity and diet, higher screen time was significantly associated with increased visceral fat, higher body fat mass index and body fat percentage. It was also linked to lower cardiorespiratory fitness and slightly lower levels of HDL cholesterol.
Further analysis showed that cardiorespiratory fitness played a substantial mediating role, accounting for around two thirds of the association between screen time and adiposity measures. Its influence on HDL cholesterol was more modest, explaining just over one fifth of the association.
The authors suggest several mechanisms through which screen time may contribute to increased adiposity, including distracted eating, longer eating duration, exposure to unhealthy food advertising and sleep disruption related to blue light exposure. They conclude that strategies combining screen time reduction with efforts to improve physical activity and cardiorespiratory fitness may help support healthier body composition and metabolic profiles in children.