Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pop health > Lecture 17 Cross sectional studies > Flashcards

Lecture 17 Cross sectional studies Flashcards

1
Q

descriptive epidemiology definition

A

distribution of health-related

states or events in specified populations…”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Analytic epidemiology definition

A

determinants of health-related states or events in specified populations…”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is descriptive epidemiology?

A
  • ‘Person, place and time’
  • Observational
  • What
  • Who
  • Where
  • When
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is Analytic Epidemiology?

A 
• Associations: exposures
and outcomes
• Causation
• Observational or
intervention studies

• Why

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a cross-sectional study?

A

Measures exposures and/or outcomes at one point in time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do we mean by a ‘point in time?’

A

A particular date eg (14 August 2019)

A specific event eg (visit to doctor, retirement)

A specific period of time eg (in the past 12 months)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Some examples of cross-sectional studies

A

New Zealand Health Survey

Census of Populations and Dwellings

Youth 2000 National Youth Health and Wellbeing Survey Series

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

why are Cross sectional studies used?

A

Describe Prevalence of exposures or health conditions in a population

Compare prevalence amongst different groups in a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What do cross-sectional studies measure?

A

Prevalence: the proportion of a defined population who have a disease at a point in time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Prevalence is affected by

A

incidence AND duration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are cross-sectional studies used for?

A

To describe:
Prevalence of exposures or health conditions in a population
E.g. What is the prevalence of osteoarthritis in NZ?

To compare:
prevalence amongst different groups in a population
E.g. what is the prevalence of osteoarthritis in NZ for people of different ages?

To compare:
Compare repeated studies over time
E.g. Has the prevalence of smoking changed over time among high school students?

To generate hypotheses:
E.g. Which factors are associated with low back pain among nurses?

To plan:
health services
E.g. Population of Nelson Marlborough DHB Population by age 2015/16

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Recap: Cross-sectional studies measures

A

exposures and/or outcomes at one point in time

prevalence (affected by incidence and duration)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Recap: Cross-sectional studies used to

A

describe prevalence
compare prevalence
generate hypotheses
plan (e.g. health service delivery)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

GATE frame

A

Graphic Appraisal Tool for Epidemiological studies:

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Gate frame used for

A

Describe main elements of epidemiological study

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q 
Gate Frame 
Triangle
Circle
Square
Time
A

Population

  • Source
  • Sample

Exposure/Comparison

  • Exposed group (top circle) (exposure / potential risk factor)
  • Comparison group (bottom circle)

Outcome

Duration of study

17
Q

Cross sectional study exposure and outcome occurs

A

at same time

Time barrier changes accordingly

18
Q

What is the prevalence of “outcome”?

A

a + b / a + b + c + d

19
Q

What is the prevalence of “outcome” among those who have “exposure”?

A

a / a + b

20
Q

What is the prevalence of knee pain among those with “comparison group”?

A

c / c + d

21
Q

what is a Sample population?

A

Subset of source population who meet inclusion criteria in study and enters study

22
Q

Hypothesis generation
People who were overweight or obese were 1.47 times as likely to have knee pain as people with a normal BMI

BUT
Which came first?
Knee pain or increased BMI?

A

Exposure and outcome were assessed at the same time

23
Q

Limitations of cross sectional study

A

Unable to determine temporal sequencing between exposure and the outcome (exposure and outcome occurs at same time)

Measures prevalence not incidence
- unable to tell us about onset of disease

Not good for studying rare outcomes or exposures

Not good for assessing variable and transient exposures or outcomes
(Findings may be different depending when you do cross sectional study)

24
Q

Transient

A

Some things interested in may last short time

25
Q

why do cross-sectional studies?

A
  • Depend on research question may be most appropriate
  • Only conduct data at one point in time
  • Can assess multiple exposures and outcomes
  • Can be less expensive than some other study designs
  • Relatively quick
26
Q

what are some appropriate research question for cross-sectional studies?

A
  • Prevalence, and distribution of prevalence in the population
  • Stable exposures and outcomes
  • Hypothesis generating
27
Q

Ecological studies

A

Compare exposures and outcomes across GROUPS not individuals

28
Q

What are ecological studies used for?

A
  • To compare between populations
  • To assess population level factors
  • To consider hypotheses
29
Q

Limitations of ecological studies

A

Ecological fallacy
Cannot control for confounding
Cannot show causation

30
Q

Ecological fallacy

A
  • Unable to describe characteristics of group to the individuals in that group
  • Measure for that group
  • “…derives from ascribing to individuals the characteristics of the group.”
31
Q

Cofounding

A

Relationships looking at is muddled up by another factor

32
Q

why do ecological studies?

A

Depends on the research question

  • Population level exposures
  • Consideration of hypotheses

Data is often routinely collected

  • May be relatively easy to do
  • May be relatively inexpensive
33
Q

hypothesis of ecological study

A

may not be correct

Not used to confirm hypotheses Because can’t infer at the level of individual

34
Q

recap what is Cross-sectional studies?

A
  • Assess prevalence
  • Temporal sequence
  • Not good for rare, variable or transient exposures or outcomes
35
Q

recap what is Ecological studies?

A
  • Group level not individual level
  • Every data point is a population (not individual people)
  • Ecological fallacy
36
Q

Income inequality use

A

Group measure

Use ecological study

Pop health (24 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions