L4 - cause and association

Question 1

State the 3 things an association could also be called

Answer 1

Link, relationship, correlation

Question 2

State 4 causes of an association

Answer 2

Bias, Cause, Confounding, Chance

Question 3

What are the features of associations?

Answer 3

Statistical dependence, 2 variables, rate of disease is altered by changes in exposure

Question 4

How can chance be assessed?

Answer 4

Statistical tests, confidence intervals, reproducing results, using larger sample size

Question 5

How can confounding be reduced?

Answer 5

Use of additional controlled variables, Stratification, Regression, Standardisation

Question 6

What is bias?

Answer 6

A systematic error, defect on study design, leading to the incorrect effect of an exposure of the outcome of a disease

Question 7

How can selection bias be reduced?

Answer 7

Randomisation

Question 8

State range of factors to be considered is association is causal or not

Answer 8

Bradford Hill 1965:

Temporal relationship, plausibility, consistency, strength, dose-response, specificity, evidence, coherence, analogy

Question 9

What was the year of the Wakefield scandal and what was its effect?

Answer 9

1998; scared parents, less vaccines, more cases of MMR

Question 10

Define confounding

Answer 10

When a variable (or factor) is related to both the study variable and the outcome so the effect of the study variable on the outcome is distorted.