Incidence is the number of new cases in a specific population within a certain time period. Which term does this describe?

• A. Incidence
• B. Prevalence
• C. Epidemics
• D. Hypertrophy

Answer: (A)

Incidence describes the number of new cases of a disease that develop in a defined population during a specified time frame. It shows how quickly new cases are appearing and is typically expressed as a rate (for example, new cases per 100,000 people per year) using the population at risk during that period. This is different from prevalence, which counts all existing cases—new and old—at a particular point in time or over a period. An epidemic refers to a surge in cases that exceeds normal expectations in a community, while hypertrophy is the enlargement of tissue due to an increase in cell size, not related to new case counts. An example: if 50 people in a population of 10,000 develop the disease over one year, the incidence rate is 50 per 10,000 per year.