Comprehensive description of three-chamber distribution

The above sections describe the region, time and population distribution of the disease respectively, but the description of a disease in actual work is often comprehensive. Only by comprehensive observation and analysis can we get the clues of etiology and the information of epidemic factors.

It is a typical comprehensive description method to study the distribution of diseases and explore the causes with immigrant population, which is called migration epidemiology. The natural environment, living conditions, social environment and psychological state of immigrants in their countries of residence are different from those in their own countries. Comparing the incidence and mortality of certain diseases of their offspring after several years of settlement with the incidence and mortality of the same diseases in their own countries and immigrant countries is a comprehensive analysis of the region, time and population distribution of diseases. For example, the incidence of gastric cancer is high in Japan and low in the United States. If the mortality rate of gastric cancer in Japan is 100, the non-American-born Japanese immigrants are 55, the American-born Japanese immigrants are 48, and the white Americans are only 18. After the Japanese moved to the United States and the second generation was born in the United States, the mortality rate of gastric cancer has been greatly reduced, but it is still higher than that of white Americans. It shows that environmental factors are closely related to gastric cancer.

According to reports, the mortality rate of nasopharyngeal carcinoma in Guangdong in Dongshan District of Guangzhou is 10.9/65438+ 10,000, while that in other provinces who have settled in Guangzhou is 3.9/65438+ 10,000. In addition, the death rate of nasopharyngeal carcinoma among Guangdong residents in Yuexiu District of Guangzhou is 9.2/65438+ 10,000, that of Guangdong residents who have settled in Hongkou District of Shanghai is 7. 1/65438+ 10,000, and that of Shanghai residents in Hongkou District is only 2.7/65438+ 10,000. The above results show that both environmental factors and genetic factors play a certain role in the pathogenesis of nasopharyngeal carcinoma. This provides important clues for further study on the etiology of nasopharyngeal carcinoma.