Epidemiology Ch 3: Occurrence of Disease Surveillance and Morbidity

Vocabulary-style flashcards covering key epidemiological measures, surveillance types, and risk ratios as defined in Chapter 3 of Gordis Epidemiology.

Morbidity

Living with disease.

Mortality

Death.

Risk

The probability of an event occurring.

Surveillance (CDC Definition)

The ongoing systematic collection, analysis, and interpretation of health data essential to the planning, implementation, and evaluation of public health practice closely integrated with the timely dissemination of these data to those who need to know.

Surveillance case

A set of uniform criteria used to define a disease for public health, intended to aid public health officials in recording and reporting cases.

Passive surveillance

A method of surveillance that uses already available data.

Active surveillance

A system in which project staff are specifically recruited to carry out a surveillance program to obtain specific data, generally resulting in more complete data than passive surveillance.

Incidence Rate (IR)

\frac{\text{# of New Cases During a Period of Time}}{\text{# of persons who are at risk of developing the disease during the same period of time}} \times 10^n

Cumulative incidence

The period of time during which all of the individuals in the population are considered to be at risk for the outcome.

Person year (PY)

A measurement of time for individuals involved in a study during the year in question.

Attack Rate

\frac{\text{# new cases}}{\text{# population at risk}} or \frac{\text{# affected}}{\text{# exposed}}; typically used for acute, short-term (ST) exposures.

Primary case

A person who becomes directly ill from an initial exposure.

Secondary case

A person who becomes ill specifically from exposure to a person who was a primary case.

Prevalence

\frac{\text{# of Existing Cases at a Point in Time}}{\text{# of Persons in the Population at this Point in Time}} \times 10^n

Point prevalence

The prevalence of a disease at a specific point in time, emphasizing the lack of a time lapse.

Period prevalence

A measure of how many people have had a disease at any point during a certain time period (cumulative).

Relative Risk (RR)

Also known as Risk Ratio; represents the ratio of the risk ($IR$) of occurrence of a disease among exposed people to that among the unexposed ($\frac{IR_{exposed}}{IR_{unexposed}}$).