Which factor increases prevalence by increasing the number of new cases?

Which factor increases prevalence by increasing the number of new cases?

• A. Decreased incidence
• B. Increased incidence
• C. Shorter duration of disease
• D. In-migration of healthy people

Answer: (B)

Prevalence is the number of people living with a disease at a given time, and it grows when more new cases occur (incidence). When incidence increases, more individuals become diseased, so the count of current cases rises, pushing prevalence higher. Shorter duration reduces prevalence because people leave the diseased state sooner, so fewer people are counted as cases at any moment. A decrease in incidence would lower new cases and thus lower prevalence, while in-migration of healthy people adds more noncases to the population and doesn’t increase the number of existing cases.

Prevalence is the number of people living with a disease at a given time, and it grows when more new cases occur (incidence). When incidence increases, more individuals become diseased, so the count of current cases rises, pushing prevalence higher. Shorter duration reduces prevalence because people leave the diseased state sooner, so fewer people are counted as cases at any moment. A decrease in incidence would lower new cases and thus lower prevalence, while in-migration of healthy people adds more noncases to the population and doesn’t increase the number of existing cases.