The results, published in the BMC Medicine journal, suggest previous estimates that up to half of smokers will die from their habit vastly underestimated smoking risk.
Researchers from the Australian National University monitored more than 200,000 people aged 45 or older in Australia for four years. Almost 8% were smokers and 34% were ex-smokers.
On average, they found that smokers died around 10 years earlier than non-smokers, with mortality rates increasing ‘substantially’ in line with how much people smoked.
They found that mortality rates doubled in those smoking around 10 cigarettes a day and increased four- to five-fold among those smoking 25 or more.
Two in three smokers will die as a result of their habit if they continue to smoke, they warned. Smokers who had quit had lower mortality risk, with smokers who quit earlier in life having greater reductions.
Lead author Professor Emily Banks said: ‘We knew smoking was bad but we now have direct independent evidence that confirms the disturbing findings that have been emerging internationally.
‘Even with the very low rates of smoking that we have in Australia we found that smokers have around three-fold risk of premature death of those who have never smoked. We also found smokers will die an estimated 10 years earlier than non-smokers.’
Just short of 19% of people in the UK smoke, equivalent to around 9.4m people, according to Cancer Research UK figures.
The findings come shortly after another study, partly funded by Cancer Research UK, found that smokers are 70% more likely to report being anxious or depressed than non-smokers.