1 Flashcards
What is epidemiology in public health?
Prevention, health promoting, social, behaviour
What is epidemiology in academic setting?
Causal factors, biomedical, health and disease
What characterizes preformal epidemiology?
Hygiene +sanitation, travelling: import/export disease, infectious diseases
What characterizes early epi?
First prof in epi, non-communicable diseases (pellagra, vitamins)
What characterizes classical epi?
Academice field, tabacco, study designs (case-control, cohort..)
What characterizes modern epi?
- Theoretical basis in RCT
- Differentiation of expertise
Some major triumphs in epi?
- Identification of water as reservoir and vehicle of diseases
- Identification of vectors (flies, mosquitos)
- Cigarette smoking
- AIDS syndrome caused by sexually-transmitted virus
What is prevalence proportion? How do you calculate this?
proportion of people in a population who have the disease at a given point in time: No of people with disease/total no of people in population
How do you call no of adults with disease in specific time point vs period?
Point/period prevalence
What is the incidence proportion (IP)? How do you calculate this?
Proportion of population that develops a disease in a specified period. No of people who develop disease in a specified period/No of people at risk at the START of the period
How do you calculate the incidence rate (IR)?
No of people who develop the disease in a specified period/total PERSON-TIME when people were at risk of getting the disease
Characteristics of closed population?
- Fixed membership
- No-one can be added
- People may die, lost to follow-up
- Becomes smaller with time
- Everyone is followed
- Incidence proportion + incidence rate
- Prevalence
Characteristics of open population?
- New members with time
- Move in and out of the area
- No remain about the same
- No follow-up when leaving
- Incidence rate
- Prevalence often not?
How is prevalence related to incidence and duration?
● If incidence is low, and duration is long (chronic),
prevalence will be large in relation to incidence.
● If duration is short (due to recovery, migration or
death), prevalence will be small in relation to
incidence.
As a formula: P = IR x D
(assuming that incidence is low: stationary population)
When is incidence used vs prevalence?
- Incidence is generally
used for acutely
acquired diseases…
… prevalence is used for
more permanent states,
conditions or attributes of
ill-health
- Incidence is more
important when thinking
of etiology of the
disorder…
… prevalence when
thinking of societal
burden of the disorder
including the costs and
resources consumed as a
result of the disorder.
IP (Incidence proportion) can only be calculated in a(n) …… population. Why? And what is a synonym for IP?
Closed. Because IP = onset/people @ risk. The persons in the numerator, those who develop disease, are all included in the denominator (the entire population). It is the risk, or average risk or attack rate.
IR (Incidence rate) can be calculated in a(n) … population
Closed & open.
