Prevalence and Incidence of Disease
And the incidence and prevalence
1. Prevalence refers to the number of all cases (both old and new) are diseases that can be defined within a given population at a given point in time (Fig. 5-2).
For example, in 2002 a study of 100 white population in the age from 35 to 45 years old, was done with the prevalence of 50% of this population is recorded as having bleeding when probing. In bleeding gums index (GBI) was used to record bleeding. This prevalence information is not specified how long these people had bleeding gums when probing.
2. Incidence-the number of new cases of a disease in a population that occur during a specified period of time.
For example, a subsequent study in 2003 is higher than the adult population have shown that the incidence of 10 additional cases are not recorded as bleeding after sensing. Now, a new prevalence bleeding after sensing with this group of the population by 60%.