The hours children spend indoors playing computer games or watching television may be to blame for a resurgence of rickets, The Times of London revealed Friday.

Scientists say that rickets is becoming "disturbingly common" among British children. The disease is caused by chronic vitamin D deficiencies, which can be triggered by long periods out of natural sunlight and a poor diet.

Writing in the British Medical Journal, Professor Simon Pearce and Dr. Tim Cheetham, of Newcastle University, called for milk and other food products to be supplemented with vitamin D in an attempt to counteract the problem.

Vitamin D is produced naturally when the skin is exposed to sunlight, and is also found in a small number of foods, including oily fish, liver and egg yolks.

Recent studies show that the incidence of rickets, a disease previously linked with poverty in Victorian Britain or malnutrition in the developing world, is increasing. More than 20 new cases are discovered every year in the northern England city of Newcastle alone.

Children with rickets do not grow properly and can develop bow legs.

Dr. Cheetham, a senior lecturer in pediatric endocrinology, added: "I am dismayed by the increasing numbers of children we are treating with this entirely preventable condition. Fifty years ago many children would have been given regular doses of cod liver oil, but this practice has all but died out."

For more on this story, see The Times of London.