35 - Aetiology and Risk Factors for CVD Flashcards Preview

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Flashcards in 35 - Aetiology and Risk Factors for CVD Deck (34)
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1
Q

Two broad types of research questions

A

1) Descriptive (EG: how common is coronary heart disease?)

2) Analytical (EG: does dyslipidaemia increase risk of CHD?)

2
Q

Examples of descriptive studies
1)
2)
3)

A

1) Case studies, reports
2) Ecological studies
3) Cross-sectional

3
Q

Examples of analytical studies
1)
2)
3)

A

1) Case-control studies
2) Cohort studies
3) Clinical trials (interventional)

4
Q

Longitudinal vs non-longitudinal studies

A

Longitudinal studies involve following subjects over time. Non-longitudinal studies only give data on one point in time

5
Q
Examples of non-longitudinal studies 
1)
2)
3)
4)
A

1) Case-studies
2) Ecological reports
3) Cross-sectional studies
4) Case-control studies

6
Q

Examples of longitudinal studies
1)
2)

A

1) Cohort studies

2) Clinical trials

7
Q

Prevalence

A

Number of existing cases of outcome of interest at a point in time in a defined population

8
Q

How is prevalence expressed?

A

As a proportion or percentage

9
Q

Examples of prevalence
1)
2)
3)

A

1) Percentage of Australians who smoke
2) Percentage of 65 year-old Australians with coronary heart disease
3) Percentage of these who smoke

10
Q

Incidence

A

Number of new cases of outcome of interest in a defined population, observed over a defined period

11
Q

How is incidence expressed?

A

As a proportion

12
Q

Only source of data for calculating incidence

A

Longitudinal studies

13
Q

Examples of incidence
1)
2)

A

1) Number of Australians who started smoking in 2014

2) Number of 65 year old males who began smoking in 2014

14
Q

Common measurement of incidence

A

Number of outcomes of interest/1000 people per year

15
Q

Risk

A

Probability of disease occurring in a disease-free population during a specified time period

16
Q

How is risk calculated?

A

N/P
N = number of new cases in a defined period
P = population at risk

17
Q

Issue with risk

A

P = population at risk assumes that all subjects were measured for equal periods of time.
EG: in 1995, 3 cases of lung cancer developed out of 1000
men; risk = 3/1000 per year.
This assumes that all 1000 men were followed for the entire year, which is not necessarily the case.

18
Q

Rate

A

Probability of disease occurring in a disease-free population during the sum of the individual follow-up periods

19
Q

Benefits of rate
1)
2)

A

1) Takes into account different measurement times for subjects.
2) Recruitment of subjects can be staggered. Each subject can have a different baseline time.

20
Q

Hazard
1)
2)
3)

A

1) Special kind of rate that is continuously updated as a longitudinal study progresses.
2) Is an instantaneous rate - applies to one particular point in time.
3) Derived from longitudinal studies

21
Q

Absolute risk/rate

A

Isolated measurement of risk/rate.
Says nothing about association with exposure.
EG: 3/1000 myocardial infarcts/year

22
Q

Ways to indicate association

A

Relative risk and attributable risk

23
Q

Which absolute risk-rate measurements of relative and attributable risks rely on?
1)
2)

A

1) Risk/rate among exposed

2) Risk/rate among unexposed

24
Q

Synonyms of relative risk

A

Risk ratio, rate ratio

25
Q

What does relative risk describe?

A

Relative change in magnitude of risk/rate outcome, associated with exposure

26
Q

How is relative risk calculated?

A

Rate exposed/Rate unexposed

27
Q

Attributable risk synonyms

A

Risk difference, rate difference

28
Q

What does attributable risk describe?

A

Absolute magnitude of change in risk/rate outcome, associated with exposure

29
Q

How is attributable risk calculated?

A

Rate exposed - rate unexposed

30
Q

Attributable risk percent

A

(Rate exposed - rate unexposed / rate exposed) x 100

Gives percentage of incident disease among exposed that can be attributed to exposure.

31
Q

Rt

A

Incidence in total population

32
Q

Population attributable risk

A

Rt (incidence in whole population) - Ru (unexposed)

Gives excess risk of the outcome in the population due to exposure

33
Q

Population attributable risk percent

A

(Rt-Ru/Ru)x100

Proportion of incident disease among whole population that is due to exposure.

34
Q

Synonym of population attributable risk

A

Preventable fraction

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