Madrid, Oct (SF) .- People who smoke less than five cigarettes a day cause long-term damage to their lungs, says a new study led by researchers from the College of Physicians and Surgeons Vagelos of the University of Columbia, United States.
“Many people assume that smoking some cigarettes a day is not so bad – recalls study leader Elizabeth Oelsner, an assistant professor of Medicine at the Vagelos College of Physicians and Surgeons at Columbia University. But it turns out that the difference in the loss of lung function between someone who smokes five cigarettes a day versus two packages a day is relatively small. “
The researchers specifically analyzed lung function (the amount of air a person can inhale and exhale) in smokers, ex-smokers and never smokers. Lung function naturally decreases with age (from age 20), and it is well known that smoking accelerates the decrease.
Due to the large number of people in the study, more than 25,000, Oelsner and his colleagues were able to see differences in lung function between light smokers (minus 5 cigarettes / day) and heavy smokers (more than 30) than other non-smokers. They have been able to detect.
Their analysis found that lung function in mild smokers decreases at a rate much closer to that of heavy smokers than non-smokers. Compared to the rate of decrease in a non-smoker, set to zero for the analysis, the additional decrease for mild smokers is 7.65 ml / year, compared to 11.24 ml / year for heavy smokers.
That means that a mild smoker could lose about the same amount of lung function in a year that a heavy smoker could lose in nine months.
“Smoking a few cigarettes a day is much riskier than many people think,” Oelsner warns. “Everyone should be encouraged to stop smoking, no matter how many cigarettes they are using per day.”
In addition, the study also proved an assumption, based on a 40-year-old study, that the rate of decreased lung capacity normalizes within a few years of quitting smoking.
The new study shows that, although lung capacity decreases at a much lower rate in ex-smokers (an extra 1.57 ml / year compared to non-smokers) than current smokers (an extra 9.42 ml / year ), the rate does not normalize (reaches zero) for at least 30 years.