Prevalence is an epidemiological measure that quantifies the proportion of a population with a particular disease or condition at a specific point in time (point prevalence) or over a specified period (period prevalence). It is calculated as the total number of existing cases (both new and pre-existing) divided by the total population. The question's definition of "proportion of people in a population who have a particular disease at a specified point in time" is the exact definition of prevalence.

A. Incidence rate: Measures the rate of new cases of a disease in a population over a specific time period, not the total proportion of existing cases.

C. Mortality rate: Measures the frequency of death in a population, not the proportion of individuals living with a disease.

D. Relative risk: Is a measure of association that compares the risk of disease in an exposed group to the risk in an unexposed group.

E. Odds ratio: Is a measure of association that quantifies the odds of an outcome occurring given an exposure compared to the odds of it occurring without the exposure.

1. Centers for Disease Control and Prevention (CDC). (2012). Principles of Epidemiology in Public Health Practice

Third Edition. Lesson 3: Measures of Risk

Section 2: Frequency Measures. "Prevalence refers to the proportion of persons in a population who have a particular disease or attribute at a specified point in time or over a specified period of time."

2. Boston University School of Public Health. (n.d.). Measures of Disease Frequency. PH717 Module 2. Retrieved from the Boston University website. The module states

"Prevalence is the proportion of a particular population that has the condition of interest at a specified time."

3. Noordzij

M.

Dekker

F. W.

Zoccali

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& Jager

K. J. (2010). Measures of disease frequency: prevalence and incidence. Nephron. Clinical practice

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c17–c20. Page c17

Abstract. "Prevalence is the proportion of a population that has a specific characteristic at a given point in time." https://doi.org/10.1159/000286345