Prevalence

Proportion or rate of persons in a population who had a condition at any given time. Compare: Incidence.

The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time.

The total number of cases of any mental disorder that exist within a unit of population.

Frequency of a disorder, used particularly in epidemiology to denote the total number of cases for a unit of population at a given time.

The number of cases of a disease in a specific population at a given time.

The number of cases of a disease in existence at a given time and in a particular geographic area or in a given population, incidence; prevalence rate.

The number of cases of disease, infected persons, or persons with some other attribute, present at a particular time and in relation to the size of the population from which drawn. It is a measurement of morbidity at a moment in time, for example, the number of cases of hemophilia in the country as of the first of the year. The prevalence of arthritis is high relative to its incidence. Prevalence equals incidence times average case duration.

The number of cases of a disease in a specific place at a specific time.

The number of existing cases of X in a given population at a given time.

The number of events or cases of disease present in a given population at a given time. “Prevalence” is often confused with “incidence,” which is the number of new events taking place in a defined period of time in a specified area or population. Usually both incidence and prevalence refer to cases of disease or injury. Both are numerators in the calculation of an incidence rate or a prevalence rate, respectively, for the event in question. The denominator is, for both, the population at risk (the given population).

In epidemiology, number of occurrences of a disease or event during a particular period of time; it is usually expressed as a ratio, the number of events occurring per the number of units in the population at risk for the occurrence.

An epidemiological term describing the proportion of a defined group in the population haying a condition at one point in time. It is an appropriate measure only in relatively stable conditions for example, chronic bronchitis and is not suitable for measuring acute illnesses.

The number of cases of a disease present in a specified population at a given time.

The number of all new and old cases of a disease in a defined population at a particular point in time. The prevalence of MS in the United States at any given time is about 1/750: approximately 400,000 people.