According to the findings of a new study, compared to current smokers, people who had stopped smoking had four times more genetically healthy lung cells, which have a significantly lower risk of developing into cancer. These results demonstrate the benefit of quitting smoking completely, at any age, even among people who have smoked their entire lives. In fact, the researchers involved in the study, which was published in the journal Nature on January 29, found that not only can quitting smoking stop further damage to the lungs, it may also allow new, healthy lung cells to replenish the lining of the airways, which can help protect against lung cancer. This is good news for current smokers, as it means it is never too late to stop smoking cigarettes.
In the United States, lung cancer is the leading cause of cancer death among both women and men, accounting for nearly 25% of all cancer-related deaths. The authors of this new study note that “Tobacco smoking causes lung cancer, a process that is driven by more than 60 carcinogens in cigarette smoke that directly damage and mutate DNA.” On a positive note, the American Cancer Society states that the number of new lung cancer cases and the number of deaths from lung cancer in the U.S. continue to decline, due at least in part to the fact that people are quitting smoking. Unfortunately, many smokers are turning to e-cigarettes to help them quit smoking.
The makers of JUUL and other e-cigarettes have aggressively marketed their products as smoking cessation aids, a use for which they have not been approved, without warning consumers about the potential risk of nicotine addiction and other side effects associated with e-cigarette use. The problem with the growing popularity of e-cigarettes is the fact that many young users don’t even realize that e-cigarettes contain nicotine and few have a clear understanding of how potent a dose of nicotine the products deliver with each puff. According to the JUUL website, the amount of nicotine in one JUUL cartridge is equivalent to the amount of nicotine in an entire pack of cigarettes. And one recent study found that the nicotine formula used in JUUL vape pens is nearly identical to the flavor and addictive profile of Marlboro cigarettes.
Plenty of people who have smoked for years feel as though they have already done so much damage to their lungs that quitting won’t do them any good. “People who have smoked heavily for 30, 40 or more years often say to me that it’s too late to stop smoking – the damage is already done,” writes joint senior author Dr Peter Campbell, from the Wellcome Sanger Institute in the UK. “What is so exciting about our study is that it shows that it’s never too late to quit – some of the people in our study had smoked more than 15,000 packs of cigarettes over their life, but within a few years of quitting many of the cells lining their airways showed no evidence of damage from tobacco.”
According to the researchers, damage to the DNA in the cells lining the lungs caused by smoking creates genetic errors and some of these are “driver mutations,” or alterations that give the cell a growth advantage. When these so-called driver mutations accumulate, the cells can divide uncontrollably and eventually become cancerous. However, when a smoker quits smoking, they can minimize that cancer risk. In order to analyze the genetic effects of smoking on non-cancerous lung cells, the researchers examined lung biopsies from 16 people, including smokers, people who used to smoke, people who had never smoked, and children. They found that the lung cells of current smokers had up to 10,000 extra mutations compared to non-smokers and that these mutations were directly linked to the chemicals in tobacco smoke. The researchers also found that more than 25% of these damaged cells had at least one cancer-driver mutation, which demonstrates why people who smoke have a much higher risk of lung cancer.
An unexpected finding in this study was the fact that in the study participants who had quit smoking, there was a large group of cells lining the airways that did not show genetic damage caused by past smoking. In fact, these cells were genetically similar to those from people who had never smoked cigarettes before. Because these lung cells had substantially less genetic damage from smoking, they had a significantly lower risk of developing into cancer, and according to the researchers, ex-smokers had four times more of these healthy cells than current smokers. Although the results of this study show that healthy lung cells can begin to repair the lining of the airways in ex-smokers and help reduce their risk of lung cancer, smoking cigarettes also causes damage deeper in the lungs that can result in chronic lung disease, or emphysema. This kind of lung damage is not reversible, even if the person stops smoking.