LONDON - Children exposed to passive smoking have a higher risk of developing lung cancer later in life than other youngsters, according to new research. Daily exposure for many hours could treble the risk but even if children encountered second-hand smoke only on a weekly basis it could be dangerous.

"Passive smoking clearly increases the risk of lung cancer," Professor Paolo Vineis, of Imperial College London, told Reuters. "People should not smoke in the presence of their children." Vineis and his team followed up more than 123,000 people who never smoked but who had been exposed to second-hand smoke as children, to see how many developed lung cancer. They compared the occurrence of the disease in them with that in children who had not been exposed to smoke. In research reported in the British Medical Journal, they said 97 of the passive smoking youngsters suffered from lung cancer, 20 others had upper respiratory cancers and 14 more died from chronic obstructive pulmonary disease (COPD), which is also caused by smoking.

"You have approximately an increase of 50 percent risk if you are exposed to passive smoking," said Vineis. "It is much less serious than active smoking but, nevertheless, it needs to be taken seriously." Lung cancer is the leading cause of death from cancer worldwide, according to the International Agency for Research on Cancer (IARC) in Lyon, France, which is an extension of the World Health Organisation. Each year 900,000 new cases are diagnosed in men worldwide and 330,000 in women. Smoking is the main cause of the disease. In addition to increasing the risk of cancer, researchers have shown that chemical and gases in tobacco contribute to cancer of the stomach, liver, kidney and cervix.

Reuters