Middle-aged smokers are three times more likely to die than non- smokers of the same age - previous research found that smokers ran twice the risk. The health of non-smokers over the past four decades, meanwhile, has improved significantly.
Sir Richard Doll, who first demonstrated the link between smoking and lung cancer in 1951, said the more that was known about smoking, the more dangerous it appeared to be. 'It is only as the smoking epidemic has matured with the passing of time that you are getting the full effects.'
The results come from a study Sir Richard started 40 years ago of 34,000 doctors - more than half of whom have since died - who have been asked periodically to answer questionnaires on their health. Smokers and non-smokers in the group were compared to see the effect of cigarettes.
Sir Richard said the 'widening gap' between the health of smokers and non-smokers was due to two factors. 'First, the life expectancy of the non-smokers has been improving steadily. Second, the ratio of the smoker to the non- smoker death rates has grown more and more extreme.'
He said the health of doctors who gave up smoking improved significantly. 'The good news is that stopping smoking really does work.
'Doctors who abandoned the habit avoided most of their risk of death from tobacco. But the bad news is that continuing to smoke is even more dangerous than was originally realised.'
Professor Richard Peto, who has taken over the research, said most people were still unaware of the long-term dangers of smoking. 'The general public completely underestimates the risk of smoking. Tobacco kills about 30 times as many people as traffic accidents.'
Previously, scientists had estimated that about a quarter or a third of smokers would eventually die of their habit. But, Professor Peto said: 'It seems that with really prolonged smoking, about half of them would.'
Professor Peto and Sir Richard both called on the Government to ban tobacco advertising, which they said was responsible for causing many teenagers to start smoking. 'Most people who are killed by tobacco become addicted as teenagers,' Professor Peto said. 'Advertising and promotion do increase the proportion of teenagers who choose to smoke.'Reuse content