Lecture 2: Aetiology and risk factors of CVD - measurement and association

Question 1

Describe a descriptive study?

Answer 1

Assessing patterns (person/place/time) e.g. how common is CHD?

Question 2

Describe an analytical study?

Answer 2

“cause and effect” e.g. does dyslipidemia increase CHD?

Question 3

Name 4 types of non-longitudinal studies (and describe the study)

Answer 3

1) case series
2) ecological
3) cross sectional
4) case control

non-follow up, information collected on one encounter

Question 4

Name 2 types of longitudinal studies (and describe the study)

Answer 4

1) cohort
2) clinical trial

involves follow ups, information collected over multiple encounters

Question 5

Define prevalence and incidence

Answer 5

Prevalence

• number of existing cases
• expressed as PROPORTION or PERCENTAGE
• at a single point in time
• e.g. % of current smokers, %of Aus males with CHD

Incidence

• number of NEW cases
• expressed as RATE (over time)
• only from longitudinal studies
• e.g. no. of people who started to smoke in 2015, no. of males in Aus who developed CHD in 2016

Question 6

What do risks and rates measure?

Answer 6

incidence

Question 7

Define risk

Answer 7

Probability of disease developing in a population

Question 8

Define rate

Answer 8

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

Question 9

Bradford Hill criteria for causality

Answer 9

• temporal relationship
• strength
• dose-dependent relationship
• consistency
• plausibility
• exclude alternatives
• experimental evidence
• specificity
• coherence