I’m sure you’ve been told numerous times that “smoking causes lung cancer. But why do you say so? If there is no solid evidence, what is the difference between this and internet rumors? Before the 20th century, lung cancer was a very rare disease in the minds of doctors. Until 1900, there were only 140 public medical records of lung cancer. However, after the end of World War I, the number of people who got lung cancer suddenly increased, and this phenomenon attracted the attention of doctors. In 1939, a German doctor, F. Muller, published a controlled study. He found 86 people with lung cancer and dozens of people without lung cancer. It turned out that the smoking rate was higher in the lung cancer group. Beginning in 1948, British scientists Doyle and Hill conducted a sizable “retrospective matched survey” of 709 people in the lung cancer group and 709 in the control group. They not only asked the subjects whether they smoked or not, but also found out how much they were addicted to smoking. It turned out that the lung cancer patients were more addicted to smoking. The retrospective study was a horseshit and did not dispel doubts. To seal the deal, beginning in 1951, Doyle and Hill conducted a larger, longer ‘prospective matched survey’. This time, Doyle and Hill surveyed doctors in England. Because there were no electronic records in those days, only physician information was more readily available. The survey covered 40,000 doctors, and by 1956, 1,714 doctors had died of the disease. Analysis of the data revealed that the smoking group had more lung cancer. Of those 1714 doctors who died, the smoking group also had more deaths from lung cancer. So, after excluding various confounding factors, Dole and Hill proved that smoking is a significant cause of lung cancer! (P<0.01) Although this investigation was successful, the study did not stop there, but continued until 2001. In medical research we often suspect that a disease may be related to many factors. To prove from an epidemiological point of view that A is the cause of getting the disease, you must first prove two things. 1. Most people who get sick have been exposed to factor A. 2. People who have been exposed to factor A are more likely to get sick. And, you must be sure that the experimental design is not flawed and that the data analysis excludes interference. This is how two scientists, Doyle and Hill, spent 50 years proving one thing: smoking causes lung cancer! An article in the BMJ showed that tobacconists make 1 cent for every cigarette sold. For every$30,000-$40,000 they make, cigarettes take a life through lung cancer. Scientists tell us once again with the naked truth: smoking causes lung cancer! The importance of creating a healthy smoke-free environment can be imagined. May 31 is the 30th World No Tobacco Day, the theme of which is "The Threat of Tobacco to Development," and the theme of our campaign is: Smoke-free, Healthy Development. If you or someone close to you is still smoking, please tell them about the dangers of smoking and suggest that "smokers" get an early and accurate screening for lung cancer. Early and accurate screening for lung cancer is a matter of urgency Currently, the incidence and mortality of lung cancer in China continue to rise rapidly and has become the leading cause of death from malignant tumors in China, accounting for 22.7% of all deaths from malignant tumors. Smoking is still the primary risk factor of lung cancer. Long-term smoking leads to bronchial mucosal epithelial cell proliferation thus seriously affecting human lung health, and the likelihood of developing lung cancer is much higher than that of the general population. In addition second-hand smoke victims, long-term passive exposure to smoke, can also cause serious harm to the lungs.