What are immigration epidemiology and genetic epidemiology?

Q: What are the methods of immigration epidemic and gene epidemic? A: Immigrant epidemiology is to explore the relationship between the occurrence of a disease and heredity and environment by observing the differences in disease incidence or mortality among immigrants, local people in immigrant areas and people in their original places of residence. It is a research method to study the distribution of diseases and find out the causes of diseases by using foreign population, and has been used in the etiology research of tumors, chronic diseases and some genetic diseases. The epidemiological study of immigrants provides important clues for determining the cause of cancer. If cancer is caused by environmental factors, the cancer incidence rate of the residents who moved out and their descendants should be close to that of the residents who moved in. If it is caused by genetic factors, the incidence rate of the residents who moved out should be close to that of their descendants, but different from that of the residents who moved in. Genetic epidemiology is a branch of genetics, which studies the relationship between the interaction of genes and their variation with environmental factors and the occurrence, prevalence and control of diseases. The analysis methods of genetic epidemiology mainly include family investigation and family analysis, twin analysis, case-control study, combination of family investigation and group investigation, half-sib and adopted son analysis, morbidity and mortality analysis, path analysis, segregation analysis, linkage analysis and correlation analysis, and ecological genetics methods.