London: Current smokers faced nearly three times the risk of premature death from cardiovascular disease compared with people who never smoked, with the risk being higher among those who began smoking during childhood, say researchers.
"It was surprising to see how consistent these findings were with our earlier research and with other studies from around the world both in terms of the substantial risks associated with smoking and with the health benefits of quitting smoking," said lead study author Blake Thomson from the University of Oxford in the UK.
The age at which a person begins smoking is an important factor, and those who start smoking at a young age are at especially high risk of dying prematurely, the study, published in the Journal of the American Heart Association, reported.
However, quitting can substantially reduce that risk, especially for those who quit at younger ages. Getting people to quit smoking remains one of the greatest health priorities globally.
Using data collected between 1997 and 2014, from the annual US National Health Interview Survey, researchers examined the medical histories, lifestyle habits and demographics of smokers and non-smokers.
The study included 390,929 adults, aged 25 to 74 years, 56 per cent female. Occasional smokers were excluded from the study. Current smokers were grouped by the age at which they began smoking.
During the follow-up period, 4,479 people died before the age of 75 from heart disease or stroke.
After adjusting for potential confounding variables, such as age, education, alcohol consumption, region and race, researchers found 58 per cent were never smokers, 23 per cent were ex-smokers, and 19 per cent were current smokers.
Among current smokers, two per cent had started smoking before age 10, and 19 per cent began smoking between ages 10 and 14.
Those who quit smoking by the age of 40 reduced their excess risk of premature death from cardiovascular disease by about 90 per cent.
Quitting smoking at any age offered benefits, and the earlier a person quit, the better, according to the findings.
The analysis found that when compared to peers who had never smoked, those who were current smokers had nearly three times the risk of dying prematurely from heart disease or stroke.
The researchers said that more research is needed to better clarify the mechanisms by which prolonged smoking from childhood affects cardiovascular risk.