Exercise as it relates to Disease/Could adjusting TV viewing habits reduce obesity in children?

What is the background to this research?

Childhood obesity is currently a major global public health issue and the prevalence has continued to increase at a concerning rate. Overweight and obese children are more likely to stay obese into adulthood. They are also more likely to develop diseases such as diabetes and cardiovascular diseases at a younger age.

Overweight, obesity and their associated diseases are mostly preventable. Therefore prevention of childhood obesity is critical. Many preventative measures solely focus on altering dietary intake and physical activity but are unsuccessful at reducing obesity rates. Because of this, it’s important that other methods are discovered in order to prevent obesity.

Children in America spend the majority of their time watching television and playing video games than doing anything else other than sleeping. Television viewing is generally considered to be a factor in increasing obesity. This is because the act of watching television is sedentary behaviour, which reduces energy expenditure compared to doing physical activity. It may also contribute to added dietary energy intake, either during viewing or as a consequence of food advertising.

Both these factors, decreased energy expenditure and increased dietary energy intake, are two main causes that promote obesity. This study aims to prevent obesity by modifying children’s television viewing habits. The title of the article observed is “Reducing Children's Television Viewing to Prevent Obesity”.

Where is the research from?

This research was conducted in San Jose, California from September 1996 to April 1997. The study was developed by Thomas N. Robinson, MD, MPH, who is a renowned professor in pediatrics. His research is focused on finding solutions within health promotion and disease prevention interventions for children and their families.

In this study, two public primary schools similar in socio-demographic and education characteristics were matched to participate. Third- and fourth-grade students were eligible, and consent was obtained from parents or guardians. Parents and guardians agreed to participate in telephone interviews. School teachers also agreed to participate in the study.

The study randomly chose one school to implement a program to reduce television use. The other school was designated to be the control group, which was assessed only and not given an intervention. Participants and school personnel understood the intervention but didn’t know the primary hypothesis.

What kind of research was this?

The research implemented a randomized controlled trial. RCTs are considered to give the most accurate evidence on the effectiveness of interventions. This is because the methods used while carrying out an RCT reduce the risk of confounding variables affecting the results.

What did the research involve?

The intervention needed to assess the link between body fatness and the use of television, videotape, and video game use without purposely encouraging physical activity as an alternative to screen time. To achieve this, an intervention was used to instruct and alter behaviour through limiting access of television and developing more selective viewing. Teachers were trained by research staff to deliver the intervention to children.

The intervention began with teachers giving lessons for the children to self-monitor and report screen use to motivate them to want to decrease their screen time. The children were challenged to not watch television or videos, and play no video games for 10 days. After this challenge they were encouraged to “budget” for 7 hours a week of screen time. They were given more lessons to educate them to be "intelligent viewers" by being more selective with their screen time.

Parents received newsletters that were created to motivate the parents to assist their children to stick to their screen time “budgets”. It also informed them of ways that the whole family could manage screen time. Every household was also given electronic television time managers for every television in the house. These monitored “budgeted” screen time for each individual through the use of personal identification codes. This ensured time was monitored accurately, although a limitation could be that multiple participants watched television together and therefore shared and saved some of their own “budget” time.

What were the basic results?

The results were statistically significant. Children who were in the intervention group had major decreases in body mass index compared to the control group. The intervention group also had considerable decreases in triceps skinfold thickness, waist circumference and waist-to-hip ratio. Compared to the controls, the intervention group also presented a decrease of the children's reported television viewing and meals eaten in front of the television.

There were no notable differences between groups for changes in high-fat food intake, moderate to vigorous physical activity or cardiorespiratory fitness.

What conclusions can we take from this research?

This intervention was largely successful compared to many other interventions, specifically those that aimed to increase physical activity and decrease dietary intake. It was a simple intervention that exclusively attempted to modify television-viewing habits that had an outcome of positive effects. In 7 months, the participants in the intervention group had favorable changes in their BMI, triceps skinfold thickness, waist circumference and waist-to-hip ratio.

All participants experienced these positive changes, meaning that the entire group’s overall amount of adiposity (body fatness) was decreased. The results provided by this research may suggest that the approaches used in the intervention could be used to attempt to decrease adiposity at a larger scale. If adiposity decreased similarly to the results in this study in larger populations, morbidity and mortality caused by obesity would also decline.

This research reveals that we are able to help prevent childhood obesity by modifying screen time habits. The findings present a favorable outcome produced by practical and simple actions. More research is needed to assess if similar outcomes would occur with larger samples.

Practical advice

This research shows us the positive effect that reducing screen time can have on the prevalence of childhood obesity. Therefore it shows us that we need to be mindful of the amount of time we spend in front of the television. The most practical suggestion is for children and their families to put time limits on screen time.

Based on The Australian National Physical activity and sedentary guidelines the recommended screen time for children aged under two years is zero screen time, children aged 2-5 years is less than 1 hour per day, and between ages 5-17 years it is less than two hours per day.

Further information/resources

For more information on recommendations regarding children’s television viewing: https://austparents.edu.au/parentech_resources/screentime