Incidence

From WikiMD's Wellness Encyclopedia

Incidence refers to the occurrence, rate, or frequency of a disease, crime, or something else undesirable. In epidemiology, it is a measure of the risk of developing some new condition within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period, it is better expressed as a proportion or a rate.

Definition[edit | edit source]

The incidence of a medical condition is the frequency at which it occurs in a population over a certain time period. It is commonly reported in the number of cases per 1,000 or 100,000 people per year. The incidence rate is the number of new cases per population at risk in a given time period[1].

Calculation[edit | edit source]

When the denominator is the sum of the person-time of the at risk population, it is also known as the incidence density rate or person-time incidence rate. Using person-time rather than just time handles situations where the amount of observation time differs between people, or when the population at risk varies with time[2].

Incidence versus Prevalence[edit | edit source]

Incidence should not be confused with prevalence, which is a measure of the total number of cases of disease in a population at a given time rather than the rate of occurrence of new cases. Thus, incidence conveys information about the risk of contracting the disease, whereas prevalence indicates how widespread the disease is[3].

See Also[edit | edit source]

References[edit | edit source]

  1. Porta, Miquel, ed. (2014). "Incidence rate". A Dictionary of Epidemiology (6th ed.). Oxford University Press. p. 112. ISBN 978-0-19-997673-7.
  2. Porta, Miquel, ed. (2014). "Incidence rate". A Dictionary of Epidemiology (6th ed.). Oxford University Press. p. 112. ISBN 978-0-19-997673-7.
  3. Porta, Miquel, ed. (2014). "Incidence rate". A Dictionary of Epidemiology (6th ed.). Oxford University Press. p. 112. ISBN 978-0-19-997673-7.
Incidence Resources
Wikipedia
WikiMD
Navigation: Wellness - Encyclopedia - Health topics - Disease Index‏‎ - Drugs - World Directory - Gray's Anatomy - Keto diet - Recipes

Search WikiMD

Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD

WikiMD's Wellness Encyclopedia

Let Food Be Thy Medicine
Medicine Thy Food - Hippocrates

Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.

Contributors: Prab R. Tumpati, MD