Lecture 16 Flashcards
3 measures of occurrence
- prevalence
- incidence proportion
- incidence rate
Definition of Epidemiology
“ The study of the occurrence and distribution of health-related events, states or processes in specified populations…”
Why measure disease occurrence in populations?
- health status
- impact among different groups
- trends over time
Two measures of occurrence
What is prevalence
The proportion of a population who have the disease at a point in time
Prevelance
Why do we measure prevalence ?
• Burden of disease
• Resource allocation
Calculation of prevelance in a population
Must have all 5 to interpret findings in prevalence reporting
Limitiations when measuring prevelance
- Difficult to assess the development of disease
- Is influenced by the duration of the disease
Which of the following would be the most appropriate numerator for determining the prevalence of measles on 31 December 2022?
a. The number of people diagnosed with measles during 2022
b. The total number of people in the population on 31 December 2022
c. The number of people with measles on 31 December 2022
16
C
Incidence proportion is sometimes referred to as
cumulative incidence
The influence of duration of the disease on prevalence
What is the incidence
The occurrence of new cases of an outcome in a population during a specific period of follow-up
- incidence proportion (IP)
- incidence rate (IR)
Key difference between IP and IR
what we use as the denominator