Why do some people smoke all their lives but never get lung cancer? New research reveals the truth

It is an indisputable fact that smoking is harmful to health. But when you persuade people around you to quit smoking, they may refute you by saying, "So-and-so smoked all his life and never got lung cancer."

Judging from global big data, although smoking is the main cause of lung cancer, in reality, only a small number of smokers will develop lung cancer.

Why do most smokers not develop lung cancer? Does this mean that smoking has no effect on the lungs? A new study recently revealed the connection.

Combining new research and interviewing experts, this book tells you the harm that smoking causes to most people and teaches you some effective ways to quit smoking.

Recently, a study published in Nature Genetics, a subsidiary of the authoritative British medical journal Nature, pointed out that some long-term smokers may have a powerful self-protection mechanism in their bodies to limit DNA mutations caused by smoking, thereby reducing the risk of lung cancer.

The study was conducted by Albert Einstein College of Medicine in the United States, and the main findings of the experiment are as follows:

DNA mutations accumulate in lung cells with age and the amount of smoking. Smokers are more likely to have DNA mutations than non-smokers.

That is to say, 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 can trigger DNA mutations in normal lung cells and lead to lung cancer.

When the number of cigarettes smoked reaches 23 pack-years (1 pack-year: number of packs smoked per day x number of years of smoking), the increasing trend of DNA mutations will tend to stabilize.

Researchers pointed out that when the amount of smoking exceeds a certain critical point, it will trigger the self-protection mechanism in the smoker's body and enter a stable period of DNA mutation. It is this powerful DNA repair ability that helps to resist the damage caused by smoking that leads to lung cancer. Therefore, many smokers do not eventually develop lung cancer.

Although the above research provides an excuse for some "lucky people" who refuse to quit smoking, the purpose of the research is to detect the individual's DNA repair ability to determine the risk of lung cancer.

Smoking harms the lungs and may delay the onset of symptoms by more than 10 years

Even though long-term smoking may not necessarily cause people to develop lung cancer, there is no safe amount of smoking, and its damage to the lungs has a lag.

In 2019, research published in the top international medical journal The Lancet showed that former smokers and low-dose smokers have faster lung function decline and cause long-term irreversible damage to some target organs compared with never smokers.

After more than 30 years of lung function tracking tests on 25,000 smokers aged 17 to 93, Columbia University and the National Institutes of Health found that the lung function damage of light smokers (less than 5 cigarettes a day) in 12 months was basically the same as the degree of damage of heavy smokers (>30 cigarettes a day) in 9 months.

The damage of smoking to the lungs can be divided into the following processes:

The inflammation and oxidative stress response caused by smoking causes inflammatory damage, degeneration and necrosis of the airway mucosa;

The natural protective function of the airways is weakened, which in turn damages the bronchioles and causes small airway obstruction, thereby significantly reducing lung function and leading to the occurrence of chronic bronchitis, asthma, and COPD.

The impact of tobacco on people has a delayed effect, sometimes even delayed by 10 to 30 years. As people age and age, their lung function will decline physiologically, and smoking will accelerate this process.

The probability of smokers developing COPD is almost five times that of non-smokers. Once COPD occurs, the decline in lung function is irreversible. The rate of decline in lung function of those who quit smoking will be alleviated, but it will still not return to the state before smoking.

In addition, some smokers may think that since they have been smoking for a long time and their lung function has been damaged, they might as well not quit smoking. However, the study shows that after people quit smoking, the damage to their lung function will be reduced by 80% compared to when they were smoking, which is a considerable improvement. Therefore, it is never too late to quit smoking.

Cardiovascular collapse, the ignored threat of smoking

Compared to the damage to the lungs caused by smoking, many people may not realize that cardiovascular disease is the biggest invisible harm of smoking.

Nicotine and other toxins contained in cigarettes can damage the vascular endothelium, causing vascular spasms, increasing heart rate, blood pressure and cholesterol, increasing the possibility of blood clot formation, and inducing atherosclerosis.

Once atherosclerotic plaques rupture or fall off, they will block blood vessels in a short period of time, leading to acute myocardial infarction or cerebral stroke, which is seriously life-threatening.

Long-term smoking can induce cardiovascular diseases such as coronary heart disease, arrhythmia and atrial fibrillation, especially coronary heart disease, and passive smokers will also suffer great harm.

According to data from the World Health Organization, the British Imperial Cancer Research Fund and the American Cancer Society, one person dies from smoking-related diseases every 10 seconds. Studies have found that smoking not only harms the lungs, but can also lead to a variety of cardiovascular diseases.

In 2020, an eight-year follow-up study involving 900,000 people by Uppsala University in Sweden found that smoking can cause seven cardiovascular diseases, including coronary heart disease, heart failure, abdominal aortic aneurysm, ischemic stroke, transient ischemic attack, peripheral arterial disease, and hypertension.

Researchers remind that if you can quit smoking before you get sick, after 10 to 15 years, the mortality rate of smokers who quit smoking will not be much different from that of non-smokers.

It takes 5 years of abstaining from smoking to be considered as a true “quit”

Quitting smoking is not achieved overnight, but a gradual and phased success. Clinical smoking cessation usually includes the following stages:

Thinking in the early stage: I don’t want to quit smoking;

Thinking period: With the deepening understanding of the harm of smoking, on the one hand, I realize that I should quit smoking, but on the other hand, I still find it difficult to give up;

Preparation period: After a period of time, start planning to quit smoking;

Action period: putting smoking cessation into practice;

Maintenance stage: The smoking cessation behavior is consolidated. If it can be sustained, the smoker will successfully quit smoking. If it is not consolidated, the smoker will enter the relapse stage and may return to the thinking stage again.

The longer you quit smoking, the more stable your results will be. Generally speaking, 5 years of not smoking at all is considered a success.

Among them, withdrawal reaction is a normal phenomenon in the process of quitting smoking. It usually begins to appear a few hours after stopping smoking. It is most intense within the first 14 days of quitting smoking, and then gradually subsides until it disappears.

It is recommended to stay away from other smokers, limit alcohol consumption, etc.; replace smoking with compensatory behaviors such as drinking water, chewing sugar-free gum, taking a walk, listening to music, etc.