Lec 5: Descriptive Epi Flashcards
Descriptive Epidemiology
describes/characterizes amount and distribution of dx in a population according to:
person
place
time
3 objectives for descriptive epi
- eval of trends
- basis of planning and eval (i.e. setting up resources/care)
- ID of problems
3 types of Epi hypotheses
- Positive declaration (alt hypothesis)
- Negative declaration (null hypothesis)
- Implicit question (general declaration of what’s being studied
Positive declaration
1 of 3 types of Epi hypotheses
alt hypothesis
Negative declaration
1 of 3 types of Epi hypotheses
null hypothesis
Implicit question
1 of 3 types of Epi hypotheses
(general declaration of what’s being studied
5 Logical “canons” behind epi hypotheses creation
- Method of difference
- Method of agreement
- Method of concomitant agreement
- Method of residues
- Method of analogy
Canon
general law/principle
Method of difference
1 of 5 logical “canons” behind epi hypotheses creation
when you ensure that all conditions between comparison groups/treatments are exactly the same EXCEPT the one you’re studying
Method of agreement
1 of 5 logical “canons” behind epi hypotheses creation
the idea that if a factor is present in the occurrence of an event (i.e. dx onset), then it must contribute to the occurrence of that event
Method of concomitant agreement
1 of 5 logical “canons” behind epi hypotheses creation
the idea that dependent variable (dx frequency) varies based on the intensity/frequency of exposure to independent variable
Method of residues
1 of 5 logical “canons” behind epi hypotheses creation
when contributing independent variable are removed from a condition systematically in order to determine which variable is actually impacting the dependent variable
Method of analogy
1 of 5 logical “canons” behind epi hypotheses creation
the idea that an unknown dx that is similar to a better know dx must have similar mechanisms.
Epi description in terms of ‘person’
age (most important/most impactful on health) gender marital status race ethnicity etc
Epi description in terms of ‘place’
geographical location (exp. urban vs rural) of a population
Epi description in terms of ‘time’
cyclic/seasonal dx frequencies
point source epidemics/outbreaks (can always be traceback to a single ‘point’ or ‘source’ during a single time period
common source epidemics (share sources but occur continuously or sporadically)
Secular time trends (when dx frequency changes gradually over time)
Epi description in terms of ‘person’: GENDER
health differentials r/t:
reproductive needs/anatomy
environmental factors (like dangerous jobs)
gender gaps in care
Epi description in terms of ‘person’: MARITAL STATUS
married people have lower mortality
married men more likely to be overweight/obese
Epi description in terms of ‘person’: RACE/ETHNICITY
Black ppl have higher mortality than white ppl
Inuit/indigenous ppl have higher morbidity (exp. TB & hep, suicide, etc) that the rest of U.S.
Asian ppl have lower mortality than white ppl
Hispanic/Latino ppl have lower mortality than white and black ppl but have diabetes
Epi description in terms of ‘person’: RACE/ETHNICITY
Black ppl have higher mortality than white ppl
Inuit/indigenous ppl have higher morbidity (exp. TB & hep, suicide, etc) that the rest of U.S.
Asian ppl have lower mortality than white ppl
Hispanic/Latino ppl have lower mortality than white and black ppl but have stuff like diabetes
Epi description in terms of ‘person’: SES, Country of Origin, Religion
Other metrics for ‘person’
Epi description in terms of ‘person’: SES, Country of Nativity/Origin, Religion
Other metrics for ‘person’
2 types of dx/case clustering
spatial
temporal
Spatial dx/case clustering
1 of 2 types of dx/case clustering
when health events cluster over a particular place
Temporal dx/case clustering
1 of 2 types of dx/case clustering
when health events cluster over a particular time period
cyclic/seasonal dx frequencies
1 of 4 types of Epi description in terms of ‘time’
changes in the frequency of a health outcome that ebbs and flows in a cyclic or seasonal manner throughout a longer time period
point source epidemics/outbreaks
1 of 4 types of Epi description in terms of ‘time’
can always be traced back to a single ‘point’ or ‘source’ during a BRIEF time period (usually a single incubation period if infection)
may involve sharp increase in cases followed by a slow decline in cases
common source epidemics
1 of 4 types of Epi description in terms of ‘time’
involves intermittent/ongoing exposure to the source of a health outcome over time
Secular time trends
1 of 4 types of Epi description in terms of ‘time’
when health outcome frequency changes gradually over time
