# Attribute risk and strategies for prevention. Flashcards

If a risk ratio of disease A and odds ratio of disease B are equal in value then the association seen in both diseases are the same. True or false?

False. A risk ratio shows stronger association as the odds ratio is always further from the null.

Why do you need to take into account relative ratios instead of just using association measures?

As relative measures are needed to take into account impact at the population level.

What are absolute measures used for (2 things) ?

- Policy decisions.

2. To allocate resources.

Name three examples of absolute measures.

- Risk difference.
- CI.
- Prevalence.

What are relative measures used for?

- To determine the strength of association.
- To determine a causal relationship.
- To explore aetiology.

What does attributable risk assume (3 things)?

- Causal relationship.
- No source of bias.
- The distribution of other known and unknown factors is the same in exposed and unexposed groups (this includes background exposure).

What does the attributable risk assess?

The impact of removing the exposure from the whole population or from exposed individuals.

Background exposure is a constant. True or false?

It is true in a given population but varies between populations.

What should you always state when stating the AR?

A time period.

What is the formula for the AR?

AR= R1-R0.

When will you use the term ‘risk difference’ instead of ‘attributable risk’?

When you do not know if the exposure is a causal factor.

What does NNT stand for?

Number needed to treat.

What formula for NNT is needed to prevent one case of disease?

1/AR.

What is the definition of AR%?

The proportion of disease in the exposed group that can be attributed to the exposure of interest. This proportion of disease could be removed if you removed the exposure.

What is the formula of the AR%?

(Iexposed-I unexposed)/1exposed = (RR-1)/RR x100.