Prolonged TV viewing linked to childhood asthma risk
03 March 2009

Young children who spend more than two hours watching television every day double their risk of developing asthma, according to research published in the medical journal Thorax.



Dr A Sherriff and colleagues from the University of Glasgow followed more than 3,000 children from birth to 11-and-a-half years old. Their parents were asked annually about symptoms of wheezing among their children and whether a doctor had diagnosed asthma in their child by the age of seven-and-a-half, but not before the age of three-and-a-half.  



Parents were also asked to assess their children’s TV viewing habits from the age of three-and-a-half, and these were subsequently compared with peers who had no symptoms.

The prevalence of asthma among children at the age of 11-and-a-half, who had no asthma symptoms when they were aged three-and-a-half was 6%. But children who watched TV for more than two hours a day were almost twice as likely to have been diagnosed with asthma as those who watched less. 



By the time the children were 11-and-a-half there was little difference in levels of sedentary behaviour between those with asthma and those without. The results were not confined to one gender, nor were they related to current weight.



The authors comment that the relationship between physical activity, sedentary behaviour and asthma is complex. But they point out that recent research has suggested that breathing patterns in children may be associated with sedentary behaviour, sparking developmental changes in the lungs and subsequent wheezing.

Dr Elaine Vickers, Research Relations Manager at Asthma UK said: ‘This study does not suggest that watching TV directly causes asthma but uses the amount of time children spend in front of the television as an indication of how much time they spend sitting down rather than running around. 



‘The findings add to a wealth of evidence linking a lack of exercise and being overweight with an increased risk of asthma, but this study is the first to directly link sedentary behaviour at a very young age to a higher risk of asthma later in childhood. 
 


‘We have one of the highest rates of childhood asthma in the world so it is especially important that parents in the UK try to prise their kids away from the TV and encourage them to lead an active lifestyle. This includes children with asthma, who can also greatly benefit from regular exercise.’