Smokers are taking 10 years off their lives

"We used to say in the 1960s that smoking was like throwing dice in terms of whether you would die from it or not," Australian National University health expert Emily Banks said. "Then we said it was like tossing a coin. Now, we're finding two-thirds of deaths in current smokers are attributable to smoking."

Professor Banks led a study of 200 000 Australians over 45 that found those who smoked were knocking an average of 10 years off their lives.

Those smoking 10 cigarettes a day doubled their risk factor and those puffing more than 25 a day quadrupled it.

"There's no threshold under which there's not a risk," Banks said. "But quitting at any age reduces your risk and the younger you are when you stop the better."

The Sax Institute's 45 and Up study is the largest of its kind in the southern hemisphere. Banks said it echoed similar findings in Britain and the United States.