That smoking can cause up to two-thirds of deaths in current smokers in Australia has come out patently clear in a study of over 2,00,000 individuals aged over 45 years sampled from the general population of New South Wales.
The Sax Institute’s 45 and Up study results were published on February 24 in the journal BMC Medicine. Only those participants who did not have a history of cardiovascular disease, stroke, or blood clot at the start of the study were included.
The study also revealed that compared to those who never smoked, the mortality rate increased dramatically depending on the number of cigarettes smoked in a day. The rate was double in the case of those who smoked less than 14 cigarettes a day and as much as four-fold in those who smoked over 25 cigarettes a day. The researchers did not have access to information on cause of death at the time of writing the paper.
Also, smokers, both men and women, had a risk of dying nearly 10 years earlier than non-smokers over the ages studied. According to the researchers, starting from age 45 years, 44.6 per cent of male Australian smokers are estimated to die by age 75 years compared with about 19 per cent in the case of non-smoking males.
The progressive increase in the relative risk of dying earlier has been attributed to early start of smoking and greater number of cigarettes smoked a day.
The average duration of smoking in current smokers in the study was 38.5 years with a majority of them smoking for over 35 years; they smoked over 15 cigarettes a day.
But the good news is that death rates in smokers who quit smoking before turning 45 years were no different from those who never smoked. However, the death risk diminished only “gradually with increasing time from cessation.” Prevalence of smoking in Australia is estimated to be 13 per cent, one of the lowest in the world.
The present study along with those from the U.S. and U.K. indicates that up to two-thirds of deaths in the 21 Century are most likely due to smoking.