If the study of how option disease occurs in different groups of people and why they occur is called EPIDEMIOLOGICAL study. To be able to have accurate epidemiological information, the following information in any epidemiological survey need to be considered.
1- Age group
2- sex of the population
3- Geographical location of the population.
4- Their customs and traditions.
5- The level of education of the population.
6- Health Care services present within the population.
7- The level of health literacy and their believes when it comes to diseases and health abnormalities.
8- The availability of social groups and Support groups.
Etc