Since the launch of the Childhood Obesity Strategy in 2016, there has been much attention focused on the so-called ‘Sugar Tax’. The March 2017 Budget saw confirmation that sugary soft drinks would be taxed in an attempt to combat rising levels of obesity. This is an important move that has been met with widespread approval from public health professionals. Still, obesity is hugely complex and there are many other things at play in addition to the sugary drinks and snacks that children may consume. Researchers at UCL have been looking in detail at different factors associated with obesity and, in a recent paper, find that children who have a television in their bedroom have higher BMI and more body fat than those who do not. Lead researcher, Anja Heilmann, explains the research and why saying no to a TV in the bedroom could be another important strategy in combatting childhood obesity.
As our TV screens have got flatter, our children have got fatter. There is no getting away from it! Screen-based activities play a central role in our children’s lives. At a very young age, they have unparalleled access to television screens, computers, game consoles and a host of mobile devices. Among 5 to 11 year-olds, TV is still the most consumed medium, with gaming coming second.
At the same time, childhood obesity is not just a national, but a global health worry. In 2014/15 a third of 11 year-old children in England were overweight and a fifth were obese.
Research has repeatedly reported a link between TV viewing and obesity, but although some has hinted at the idea that a television in a child’s bedroom might exacerbate the problem, the evidence here has been rather contradictory. Other plausible pathways could include eating unhealthy snacks whilst watching TV, exposure to food advertising and insufficient and poor quality sleep.
Using information from the Millennium Cohort Study (MCS), which has followed the lives of more than 18,000 children born around the turn of the century, we had the opportunity to see whether having a TV in their bedroom when they were age 7 was, in any way, linked with a child being overweight when they were 11 years old. In other words, we wanted to get to grips with whether there were implications over a child’s lifetime of their screen use and if so, what those implications were.
Using trained interviewers, the MCS collects a wide range of useful information including the independently measured height, weight and body fat of a child. These provided us with a set of obesity-related measurements: weight, Body Mass Index (BMI) and Fat Mass Index (FMI), a powerful set of measures for overweight and obesity.
When the children were age seven, parents were asked if their son or daughter had a TV in their bedroom, how many hours they spent watching TV or DVDs and how much time they spent playing on a computer.
At age 7, more than half of the 12,556 boys and girls we looked at in our research had a TV in their room and it was these children who were more likely to be overweight when they turned 11 when we compared them with those without a TV. They were also more likely to have higher BMI and FMI. In total, a quarter of the boys and nearly a third of the girls were overweight at age 11 and the links between having a TV in the bedroom and overweight were stronger for the girls.
Another strength of the research is that we controlled for the child’s BMI at age 3 and maternal BMI, that way adjusting for genetic factors, as well as food environment in the family. We also adjusted for family income and mother’s education – both of which are important as overweight/obesity is socially patterned, as is TV use.
Interestingly, there was no link between overweight and the time a child, whether they were a boy or a girl, spent playing on a computer.
So, given the size of our sample and the robustness of the methods employed here, we can say with considerable confidence that there is a clear link between having a TV in the bedroom as a young child and being overweight a few years down the line. For girls, this represents a 30 per cent increase in the risk of being overweight at 11 compared with their peers who do not have one. For boys the risk increases by around 20 per cent.
Another interesting point to note is that the size of this risk or effect is about the same as that of other things shown to be linked with obesity, such as not being breastfed and being physically inactive.
Nevertheless, policy makers looking to create and implement strategies to reduce obesity should certainly consider building access to television screens in children’s bedrooms into their thinking. Specific initiatives focused on young girls could also be important.
Meanwhile, for parents who may consider it a good idea for a young child to have their own TV in their bedroom or feel under pressure to provide one, the message is quite clear: resist the idea and you may be doing even more to set your child on a healthier path into their teenage years and beyond.
Longitudinal associations between television in the bedroom and body fatness in a UK cohort study is research by Anja Heilmann, Patrick Rouxel, Emla Fitzsimons, Yvonne Kelly, and Richard Watt and is published in the International Journal of Obesity.