Cohort study on association of smoking and air pollution with lung cancer among 210,000 persons in shanghai

Survey on smoking habit and other related factors has been carried out among 110,000 persons in urban area and 100,000 persons in suburb and outer suburb area. The degrees of air pollution among three areas are different and the urban area is the one with the heaviest degree and the outer suburb with the lowest. Study on the relationship between smoking, air pollution and lung cancer has been carried out among the residents with the age of 40 years old and over in the three areas. The subjects were followed up for six years in urban area and five years in suburb and outer suburb. The total number of lung cancer death found in this period was 828. Most of these diagnosis were classified as group of high (I or II) degree. For nonsmokers, there were no significant differences of standardized mortality radio (SMR) of lung cancer among three areas. For male smokers, the highest SMR of lung cancer was seen in urban area, the lowest in outer suburb and these differences reached the significant lever. Cigarette smoking was significantly associated with increased risk of lung cancer by comparing the data between smokers and non-smokers in the three areas. Also, it was showed that the combiend effect of smoking with air pollution probably existed. The age-specific mortality rates for lung cancer among non-smokers in Shanghai urban were much higher than those in West Europe and North America, which indicated that risk factors other than smoking may exist.