LONDON: A new study by Dr Aric Sigman posits that very young children who spend long periods watching TV could be at risk in later life from disorders including premature puberty to sleep disturbances and metabolic imbalance.

Writing in Tuesday's edition of the journal of the Institute of Biology, Sigman cites several authors' concerns that too much time in front of TV or computer screens could inflict damaging long-term physiological effects on children.

Sigman, who has worked on health education campaigns with the Department of Health and acted as advisor to the Institute of Personnel Management on health and psychology issues, points to a study carried out by Italy's University of Florence.

This found that playing computer games and watching TV lowered the amount of sleep hormone, melatonin, produced by children: an effect that could advance the onset of puberty.

Other studies cited by the article suggest a possible relationship between watching TV and attention deficit disorder. Also obesity, short-sightedness and Alzheimer's disease. Warns Sigman: "There's enough evidence to suspect something is going on, so we should err on the side of caution."

And from a rather less likely source - Broadcasters Audience Research Board - comes more cause for concern: over half of UK children aged three now have a TV set in their bedroom.

BARB data also reveals that the average 75-year-old Briton has spent over twelve years watching TV. Moreover, children aged 11-15 now spend 53 hours a week in front of a screen - equivalent to 55% of their waking lives.

Data sourced from; additional content by WARC staff