Children who have a television in their bedroom at the age of seven are more likely to become overweight, according to new research.
Sitting still for long periods watching TV has long been thought to be one of the changes in behaviour of the last few decades that could be powering the obesity epidemic.
“Ironically, while our screens have become flatter, our children have become fatter,” say the authors of the study from University College London (UCL).
It has been suspected that having a TV in the bedroom might exacerbate the problem. Children or adolescents might be snacking unobserved, they could be exposed to advertising for junk food while watching adult programmes and they may not sleep as well, which is also linked to putting on weight.
The researchers used data on more than 12,000 children born in 2000/2001 who were recruited to the UK Millennium Cohort Study, set up to look at the influences on children’s development into adulthood. They investigated the data from the age of seven to 11. More than half had a TV in their bedroom.
They found that girls who had a TV in their bedroom at age seven were at an approximately 30% higher risk of being overweight at age 11, compared to children who did not have a TV in their bedroom. Boys were 20% more likely to become overweight.
The more hours girls spent watching in their room, the more likely they were to be overweight, the study found, although they had to rely on what they were told by the parents and the effect did not apply to boys. Spending hours playing on a computer, again reported by parents, did not appear to result in an increase in weight.
“Childhood obesity in the UK is a major public health problem. In England, about one-third of all 11 year olds are overweight and one in five are obese. Our study shows that there is a clear link between having a TV in the bedroom as a young child and being overweight a few years later,” said lead author Dr Anja Heilmann from the UCL Institute of Epidemiology and Health Care.
“Future childhood obesity prevention strategies should consider access to TVs in children’s bedrooms as a risk factor for obesity.”
The study is published in the International Journal of Obesity. One of its strengths, in addition to the large number of children involved, is that all participants had not only their weight and height measured but also their body fat, which allowed the researchers to be more confident as to whether they were overweight or simply had more muscle.
The researchers also had data on the children’s height and weight at the age of three, which meant they could be sure that the children were not watching TV in their room just because they were already overweight.
“As the study indicates, more research is needed to fully understand this complex area, but this is a high quality study covering a very large and nationally representative sample and provides a reasonably strong basis to think that the links shown here are real,” said Prof Russell Viner of the Royal College of Paediatrics and Child Health, who was not involved in the study. “It highlights that having a TV in the bedroom from seven years increases the risk of being overweight four years later, regardless of the child’s weight in earlier childhood. As such, the findings must be taken very seriously.”
“Furthermore, the study adds yet more weight to our recommendations for the next government to tackle this issue which include a strict ban on junk food advertising before the 9 o’clock watershed.”
Prof Nick Finer, consultant endocrinologist and bariatric physician at UCL, called it a powerful study. “The study suggests, but does not prove that a bedroom TV causes the weight gain, but is highly suggestive even if the mechanism by which it could do so is unclear,” he said.
“The authors rightly do not say that parents should not put a TV in their child’s bedroom … However it is hard not to think that parents concerned about their child’s risk of becoming overweight might appropriately consider not putting a TV in their young children’s bedrooms.”