6 factors that cause lung cancer

Primary bronchogenic carcinoma, also known as lung cancer, is the most common primary malignant tumor of the lung and a serious threat to people's health and life. The disease usually occurs in people over 40 years old, with the peak age of onset being between 60 and 79 years old. The male-female prevalence rate is 2.3:1. Race, family history and smoking all have an impact on the incidence of lung cancer.

The etiology and pathogenesis have not yet been clarified. It is generally believed that the onset of lung cancer is related to the following factors:

1) Smoking: It is generally acknowledged that smoking is an important risk factor for lung cancer. The more you smoke, the longer you smoke, and the earlier you start smoking, the higher the lung cancer mortality rate. The risk of lung cancer for smokers who quit smoking gradually decreases as the number of years they quit smoking increases, and it takes 15 years for the risk to be close to that of non-smokers. Passive smoking can also easily cause lung cancer.

2) Occupational carcinogens: Confirmed occupational carcinogens that cause human lung cancer include asbestos, inorganic arsenic compounds, dichloromethyl ether, chromium and certain compounds, nickel smelting, radon and radon progeny, mustard, vinyl chloride, soot, tar and polycyclic aromatic hydrocarbons in petroleum, heating products of tobacco, etc.

3) Air pollution: Air pollution includes indoor micro-environment and outdoor macro-environment pollution. For example, passive smoking, fuel combustion and carcinogens produced during cooking. Car exhaust, industrial waste gas and road asphalt in cities all contain carcinogens, the main of which is benzopyrene.

4) Ionizing radiation: Large doses of ionizing radiation can cause lung cancer. Different rays of radiation produce different effects. For example, Hiroshima in Japan released neutrons and gravitational rays, while Nagasaki only released gravitational rays. The former has a higher risk of lung cancer than the latter.

5) Diet and nutrition: Animal experiments have shown that vitamin A and its derivative beta-carotene can inhibit tumors induced by chemical carcinogens.

6) Others: Viral infection, fungal toxins (Aspergillus flavus), tuberculosis scars, low immune function, endocrine disorders and family inheritance may also play a certain combined role in the occurrence of lung cancer.