Influencing factors of immigration epidemiology

1. Because immigration is not random, it is selective. Some people emigrate to another place of residence because of economic, political and personal factors, so the immigrants are not random, and they may be physically strong, highly educated and healthy, while those who stay in their original place of residence are sickly and poorly educated, which affects the incidence of two groups of people in the same population.

2. If the environmental factors in the original place of residence before migration are important etiological reasons, and this influence continues to exist or play a role after migration, it will lead to the complexity of the interpretation of the results.

3. The age of immigrants is also related to environmental factors, and older immigrants are greatly influenced by the environmental factors of their original place of residence.

4. Immigration information may be incomplete.

Some diseases are caused by many factors.