London, June 22 : A new study, led by experts at Glasgow University, has revealed that smoking causes hundreds of thousands more deaths each year than previously thought.
The study showed increased risk of dying from cancers of the colon, rectum and prostate, as well as from lymphatic leukaemia.
These diseases result 930,000 deaths worldwide each year, in addition to more than five million smoking-related deaths estimated by the World Health Organisation as being caused by diseases such as lung cancer, which have long been associated with smoking.
The new study, which was based on data from 17,363 male civil servants based in London, showed that a 43 percent increase in the chances of dying from cancer of the colon if the person smokes, a 40 percent higher likelihood of dying from rectal cancer, an increase of 23 percent in the chances of losing one's life to prostate cancer and a 53 percent rise in mortality from lymphatic leukaemia among smokers.
"Cigarette smoking appears to be a risk factor for several malignancies of previously unclear association with tobacco use," the Scotsman quoted the researchers, as saying.
Dr David Batty, of the Medical Research Council Social and Public Health Sciences Unit, based at the University of Glasgow, said: "What this study shows is that smoking is linked to more kinds of cancer than previously thought. It's important to remember that cancer is not a single disease and that the various kinds of cancers are different illnesses so you couldn't necessarily assume that smoking was linked to them in the same way. What's unclear is how exactly smoking causes these cancers."
Health Minister Shona Robison said: "This study appears to demonstrate that smoking is even more carcinogenic than was realised."
Scotland's health minister and anti-smoking campaigners have welcomed the study as further proof of the need to clamp down on the habit.
The study has been published in the journal Annals of Oncology.