The Headline:

“Children who spend more than two hours a day in front of the television in early childhood are twice as likely to develop asthma as those out playing,” The Daily Telegraph reported. The newspaper said that scientists who carried out the study believe it to be the first link between the condition and a “couch potato lifestyle at a young age”.

NHS Choices says that:

The prospective nature of the study, its relatively large size, and the exclusion of children who had wheeze before the measurement of TV viewing was measured are strengths of the study. However, there are a number of limitations to consider:

  • As with all studies of this type, the differences in rates of asthma between the groups compared may be related to factors other than TV viewing (called confounding factors). Although the authors adjusted their analyses for these, such as maternal history of asthma, there may still be effects from these or other unknown confounders.
  • TV viewing was measured at one age only, and may not be indicative of TV viewing at other ages, which may have varied.
  • TV viewing was used as an indicator of sedentary behaviour, as it was thought this would be the main form of sedentary behaviour in the absence of widespread access to games consoles or computers. However, there are other sedentary behaviours, and including questions about them may have been a better indicator of overall behaviour.
  • Just under 60% of the ALSPAC group provided sufficient data for inclusion in this analysis. Results for this subgroup of participants may not be representative of the full group.
  • Parental reporting of TV viewing may not have been accurate.

Further research will be needed to investigate the suggested link between sedentary behaviour and asthma risk before any firm conclusions can be drawn. However, it is already clear that encouraging physical activity is of benefit to the health of both children and adults.

Links to the Headlines:

Children who spend hours in front of the TV are more likely to get asthma. The Guardian, March 3 2009

TV linked to asthma risk doubling. BBC News, March 3 2009

Children who watch more than two hours of TV a day 'are twice as likely to develop asthma'. Daily Mail, March 3 2009

Telly 'linked to asthma in kids'. The Sun, March 3 2009

Children who watch two hours television a day 'twice as likely to develop asthma'. The Daily Telegraph, March 3 2009

Links to the Science:

Sherriff A, Maitra A, Ness AR, et al. Association of duration of television viewing in early childhood with the subsequent development of asthma. Thorax 2009