Definition
This is the study of the distribution of a disease and the cause of death of members of a population in relation to the age, sex, and geographic origin of the individuals.
This is the study of the historical changes of the distribution of a disease.
Information can be obtained from various sources :
Medical records of diseases (e.g. cancer)
Registers of diseases that are mandatorily reported (e.g. tuberculosis)
Death certificates
Specific studies (in hospitals, in laboratories, in communities, etc.).