Smoking any number of cigarettes - even less than five a day - causes long-term harm to the lungs, as a study by scientists from Columbia University showed, The Lancet reported.
Many people think that smoking several cigarettes a day is not so dangerous, but it turns out that the difference in lung function decline between those who smoke five cigarettes a day and those who smoke two packs a day is relatively small, the stud leader said.
Scientists compared lung function, the amount of air that a person inhales and exhales, in smokers, former smokers, and never smokers. Lung function decreases naturally with age, starting at age 20, and smoking significantly speeds up this process.
Scientists examined over 25,000 people to see differences in lung function between those who smoke little, less than 5 cigarettes a day, and heavy smokers, more than 30 cigarettes a day. The analysis showed that lung function in few smokers decreases at almost the same rate as in heavy smokers. Compared to the rate of decline in those who have never smoked, the additional decrease in smokers is a little 7.65 ml / year and 11.24 ml / year for heavy smokers.
This means that someone who smokes little can lose about the same amount of lung function in a year, as a heavy smoker in nine months. Therefore, the authors advise those who smoke a little, not to flatter themselves with the imaginary “harmlessness” and to give up smoking completely.
Scientists also tested the assumption that the rate of decrease in lung capacity "normalized" within a few years after smoking cessation. A new study shows that although lung capacity decreases more slowly in smokers (by 1.57 ml / year compared to non-smokers) than in smokers (by 9.42 ml / year), complete normalization does not happen even after 30 years.