Descriptive Epidemiology

Question 1

case reports

Answer 1

-unusual case by clinician, astute observations, foster additional valence and questions

Question 2

case series

Answer 2

-larger number of similar cases that provides a summary of characteristics from several settings with case definitions and typical features

Question 3

cross sectional studies

Answer 3

-surveys of populations ti estimate prevalence or exposures
-snapshot at one point in time
-Exposure and Disease data collected simultaneously
Cannot determine or suggest cause and effect

Question 4

what are 3 descriptive types of studies

Answer 4

case reports, case series, and cross sectional

Question 5

what are 3 types of analytic studies

Answer 5

-clinical trials, case-control, cohorts

Question 6

secular trend

Answer 6

changes in disease freq over time
• across the board
• ‘vertical’ and ‘horizontal’ rates
ex causes of morbidity and mortality over past century as chronic conditions have replaced acute infections

Question 7

cohort effect

Answer 7

• group or block of persons that
share experience or exposure
(age of birth)
• patterns of ‘cells’ or cohorts as
move through time (‘diagonal
rates’)

Question 8

Analytical studies: ecologic

Answer 8

-unit of analysis is group (city, census tract, etc.)
-Uses/Pros
generate etiologic hypoth
test specific hypoth
can suggest cause and effect
Limits/Cons
Ecological fallacy:
not represent exp-dx relation at individual level
not have # of exposed cases
assoc seen at aggreg level not necess true at individ

Question 9

can ecologic studies suggest cause and effect?

Answer 9

yes, ecologic studies whose unit of analysis is the group can suggest cause and effect

Question 10

what is the ecological fallacy?

Answer 10

not represent exp-dx relation at individual level
not have # of exposed cases
assoc seen at aggreg level not necess true at individ

Question 11

describe case-control studies: are they prospective or retrospective? What types of answers are they looking for, exposures or cases?

Answer 11

Retrospective
Start with cases, then pick controls
Is there a difference in exposures?

Question 12

do case-control studies provide a direct evaluation of risk?

Answer 12

no! not provide direct evaluation of risk

Question 13

describe the three possible types of cohorts

Answer 13

Prospective, retrospective, or historical prospective

Question 14

which type of study is best for rare exposures?

Answer 14

cohort

Question 15

which type of study is best for rare condition or disease?

Answer 15

-case-control

Question 16

which analytical measure can a cohort provide?

Answer 16

direct evaluation of risk (RR = Relative Risk)