Study finds computer, television screen time directly linked to childhood obesity

SCREEN time has overtaken exercise as the most important factor in childhood obesity and should be limited, a South Australian study has found.

Child watching TV

SCREEN time has overtaken exercise as the most important factor in childhood obesity and should be limited, a South Australian study has found.

The UniSA study looked at 2200 children aged between nine and 16 years and found the length of time they spent in front of television and computer screens was a more likely indicator of being overweight or obese than the amount of exercise they did.

Study co-author and UniSA researcher Dr Carol Maher said screen time now made up about one quarter of waking time for the age group.

"In the past two decades, young people's physical activity behaviour has been the subject of scores of interventions but, in comparison, interventions aimed at reducing screen time have been relatively uncommon," she said.

"Our findings suggest that screen-time reduction may be a more effective target behaviour for intervention studies aimed at reducing overweight and obesity among children."

The study found there were about two and a half times as many obese study subjects classed in the category of high-screen-time and low-exercise (10.7 per cent), as in the low-screen-time and high-exercise category (4.3 per cent).

Dr Maher said the value of physical activity also should not be underestimated.

"Increased likelihood of a young person being overweight or obese was more strongly and consistently associated with high screen-time than with low physical activity," she said.

"Findings underscore the need for interventions targeting screen behaviour in young people."

Dr Maher said the study, published in the latest edition of Acta Paediatrica, was carried out because there was debate in the scientific community about which factor had the stronger association with obesity.

The children's behaviour over 24-hour periods was studied and they were divided into groups based on high and low activity, as well as on high and low screen use, according to national guidelines.

Low-activity children exercised for less than 60 minutes each day and high screen-time children failed to meet national guidelines.

"Increased likelihood of overweight or obese was often associated with high screen time, but only sometimes and less strongly associated with low ... physical activity," Dr Maher said.