Oct. 28 (UPI) -- Smokers are nearly three times as likely to die prematurely from heart disease than non-smokers, with the risk even higher for those who began the habit during childhood, according to a study published Wednesday by the Journal of the American Heart Association.
Those who quit between age 15 and 34 had about the same risk for dying from heart disease or a stroke as non-smokers while people who stopped the habit between age 35 and 44 had about a 20% higher risk, the data showed.
However, people who quit later in life -- between age 45 and 64 -- were up to 70% more likely to die from heart disease or a stroke, the researchers said.
"The age at which a person begins smoking is an important and often overlooked factor, and those who start smoking at a young age are at especially high risk of dying prematurely from cardiovascular disease," study co-author Blake Thomson said in a statement.
"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," said Thompson, an epidemiologist at the University of Oxford in England.
Smoking causes an estimated 100,000 deaths from heart disease every year in the United States, according to the American Heart Association.
Currently, there are about 25 million people who smoke daily, including 5 million who became regular smokers before age 15, the association estimates.
Earlier research in Cuba revealed links between childhood smoking and a higher risk for premature death -- or dying at a younger age than average life expectancy -- according to Thompson and his colleagues.
For this study, investigators set out to determine if the findings were similar for other populations by analyzing data on death from heart disease collected between 1997 and 2014 as part of the annual National Health Interview Survey, a research effort led by the U.S. Centers for Disease Control and Prevention designed to measure health trends.
Thompson and his colleagues examined the medical histories, lifestyle habits and demographics of smokers and nonsmokers among 390,929 adults age 25 to 74.
Occasional smokers were excluded from the study and current smokers were grouped by the age at which they began smoking, the researchers said.
Among the study participants, 4,479 people died before age 75 from heart disease or stroke, according to the researchers.
Of these, 58% were never smokers, 23% were ex-smokers and 19% were current smokers, the data showed.
Among current smokers, 2% had started smoking before age 10 and 19% began smoking between age 10 and 14.
Those who quit smoking by age 40 reduced their excess risk of premature death from heart disease by about 90%, the data showed.
Those who quit between age 45 and 54 had about a 60% higher risk for premature death compared to non-smokers, while people who quit between age 55 and 64 had about a 70% higher risk for death from heart disease or stroke.
More research is needed to better understand how prolonged smoking from childhood affects heart risk, as well as death from other causes, such as respiratory diseases and cancers, and in other populations, Thompson said.
"Preventing the next generation from smoking can save lives, but we must also emphasize that quitting smoking can save lives now, and in the years to come," he said.
