Smoking and lung cancer

From the beginning of the Second World War, a pioneer in epidemiological studies were started at the etiology of lung cancer, smoking is lung cancer, and even human beings all the most important cause of cancer may almost be described as a unique cause, in accordance with national survey data show that the cause of lung cancer and smoking are closely related. There are a lot of smoking on the respiratory hazards of smoking at home and abroad over the years a lot of research. Harmful substances in smoke mainly for tar, nicotine and carbon monoxide, its role in cancer and tumor promotion. Cell lung cancer and cancer-promoting complex in synergy, will become abnormal cells, and then cancer.
Smoking and risk of lung cancer and tobacco, the relationship between the type, age started smoking, number of years of smoking, smoking-related, different tobacco category in the most dangerous long-term cigarette smoking, the relative risk of up to 9.0, only cigars or pipe are lower risk, with no smoke or tar filter cigarettes are higher than the risk of lung cancer or low-tar filter those. Between smoking and lung cancer but there is a clear dose-response relationship, the study shows that smoking and lung cancer cell types have different dose - response relationship, but the intensity in the contact, smoking and squamous cell carcinoma and small cell carcinoma of the relationship between the apparent high in adenocarcinoma, and the length of the cell types of smoking than the more important volume of daily smokers, smoking age to all cell types have the dose - effect relationship, but the relationship between squamous cell carcinoma is more uncertain than for.
The other is passive smoking, the survey found that couples as long as there is a lot of smoking, another risk of lung cancer will be greatly increased. This is because the cancer-causing agents in cigarette smoke than the smokers themselves the content of inhaled more than 50 times higher. Although passive smoking is only a small amount of smoke inhalation, but the toxicity of chemical substances is considerable. This shows that passive smoking is also easy to get lung cancer are not surprising.
The results of a large number of epidemiological studies indicate that smoking cessation can lead to a decline in the incidence of lung cancer, which describes the smoking from the negative side so that the increased risk of lung cancer. Even middle-aged smokers to quit smoking will also reduce the future risk of lung cancer. Quit smoking before middle age can be reduced more than 90% of the risk attributable to tobacco. If the current smokers to give up smoking in the near future and the first half of the 21st century will continue to decline in perinatal mortality. And young people becoming persistent smokers, it would greatly affect the 21st century in the second half of the medium or mortality.