It is an indisputable fact that smoking is harmful to health. But when you persuade people around you to quit smoking, the other party may use "so-and-so has smoked all his life and has not had lung cancer" to refute it.
From the perspective of global big data, although smoking is the main cause of lung cancer, in reality, a small number of smokers will suffer from lung cancer.
Why don't most smokers get lung cancer? Does this mean that smoking has no effect on the lungs? A new study reveals the link.
Life Times (search for "LT0385" within WeChat to follow) combines new research and interviews with experts to tell you what the harm of smoking to most people is, and teach you a few ways to quit smoking efficiently.
Experts interviewed
Chen Jin, Director of the Department of Respiratory Medicine, Fuxing Hospital Affiliated to Capital Medical University
Xiao Dan, Director of the Tobacco Diseases and Smoking Cessation Center of the China-Japan Friendship Hospital
Ma Genshan, Director of the Department of Cardiology, CUHK Affiliated Hospital of Southeast University
Why don't most smokers get lung cancer?
Recently, a study published in the British authoritative medical journal "Nature Genetics" pointed out that some long-term smokers may have a strong self-protection mechanism in the body to limit the DNA mutations caused by smoking, thereby reducing the chance of lung cancer.
The study was completed by the Albert Einstein Medical School in the United States, and the main results of the experiment were found:
DNA mutations accumulate in lung cells with age and smoking, and smokers are more likely to have DNA mutations than non-smokers.
That is, excluding other factors, non-smokers are less likely to get lung cancer than smokers, while 10% to 20% of lifelong smokers are more likely to get lung cancer. Previous studies have also confirmed that smoking triggers DNA mutations in normal lung cells and causes lung cancer.
When the number of cigarettes smoked reaches 23 packs per year (1 pack per year: number of packs per day x number of years of smoking), the upward trend of DNA mutations will stabilize.
Researchers point out that smoking more than a certain critical point will trigger the self-protection mechanism in the body of the smoker and enter the plateau of DNA mutations, which is a powerful DNA repair ability that helps resist the smoking damage that causes lung cancer. As a result, many smokers end up not developing lung cancer.
Although the above study provides a reason for some "lucky people" who refuse to quit smoking, the purpose of the study is to test the ability of individuals to repair DNA to determine lung cancer risk.
Smoking hurts the lungs and may delay for more than 10 years
Even if long-term smoking does not necessarily cause people to develop lung cancer, there is no safe amount of smoking, and it has a lag in the damage to the lungs.
In 2019, studies published in the top international medical journal The Lancet showed that previous smokers and low-dose smokers accelerate the decline in lung function compared with those who have never smoked, causing long-term irreversible damage to some target organs.
Columbia University and the National Institutes of Health have found that lung function injury in mild smokers (5 < per day) for 12 months is basically the same as that of heavy smokers (30 > per day) for 9 months after more than 30 years of lung function tracking tests.
The damage to the lungs from smoking is mainly divided into the following processes:
Inflammation and oxidative stress caused by smoking, resulting in inflammatory damage, degeneration and necrosis of the airway mucosa;
The natural protective function of the airway is weakened, which then destroys the bronchi, causing small airway obstruction, resulting in a significant decrease in lung function, resulting in chronic bronchitis, asthma and COPD.
The effects of tobacco on people have a lagging effect, sometimes even delayed by 10 to 30 years. With the age of human beings, aging and other reasons, lung function will have a physiological decline, and smoking will accelerate this process.
Smokers are almost 5 times more likely to develop COPD than non-smokers, and once COPD develops, the decline in lung function is irreversible. The rate of decline in lung function in ex-smokers is relieved, but it still does not return to the state it was in before smoking.
In addition, some smokers may think that since they have been smoking for a long time and have damaged lung function, it is better not to quit smoking. However, the study showed that after people quit smoking, lung function impairment will be reduced by 80% compared with smoking, and there is a considerable degree of improvement. Therefore, it is never too late to quit smoking at any time.
Cardiovascular collapse, the threat of smoking that is ignored
Compared with smoking that hurts the lungs, many people may not realize that cardiovascular disease is the biggest invisible harm of smoking.
Cigarettes contain a variety of toxins such as nicotine, which will damage the endothelium of blood vessels, lead to vasospasm, make people's heart beat faster, blood pressure and cholesterol rise, increase the possibility of forming blood clots, and induce atherosclerosis;
Once the atherosclerotic plaque ruptures or falls off, it will block the blood vessels for a short period of time, resulting in acute myocardial infarction or stroke, which is seriously life-threatening;
Long-term smoking can induce cardiovascular diseases such as coronary heart disease, arrhythmias and atrial fibrillation, especially coronary heart disease, and passive smokers can also be greatly harmed.
According to the World Health Organization, the Imperial Cancer Research Fund and the American Cancer Society, 1 person worldwide dies from smoking-induced diseases every 10 seconds. Studies have found that smoking not only hurts the lungs, but also can lead to a variety of cardiovascular diseases.
In 2020, an 8-year follow-up study involving 900,000 people at Uppsala University in Sweden found that smoking can cause 7 cardiovascular diseases, including coronary heart disease, heart failure, abdominal aortic aneurysms, ischemic stroke, transient ischemic attacks, peripheral arterial disease, and hypertension.
The researchers caution that if you can quit smoking before you get sick, after 10 to 15 years, the mortality rate of ex-smokers will not be much different from that of non-smokers.
After 5 years of abstinence, it is truly "quit"
Quitting smoking is not achieved overnight, but a progressive, phased success. Clinical smoking cessation usually involves the following stages:
Thinking about the early stages: not wanting to quit smoking;
Thinking period: With the in-depth understanding of the harm of smoking, on the one hand, it is recognized that smoking should be quit, on the other hand, it is still difficult to give up;
Preparation period: after a period of time, start planning to quit smoking;
Period of action: putting smoking cessation into practice;
Maintenance period: The abstinence behavior is consolidated, if it can be sustained, it will be successfully quit, if it is not consolidated, the smoker will enter the relapse period, and then may return to the thinking period again.
The longer you quit smoking, the more stable your smoking cessation results will be. Generally speaking, 5 years of total non-smoking is considered successful.
Among them, withdrawal reactions are a normal phenomenon in the process of quitting smoking, usually beginning to appear a few hours after stopping smoking, most strongly in the first 14 days of quitting smoking, and then gradually lessening until they disappear.
It is recommended to stay away from other smokers, limit drinking alcohol, etc., and replace smoking with compensatory behaviors such as drinking water, chewing sugar-free gum, walking, and listening to music. ▲
Editor of this issue: Zhang Yu
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