# 7: Evidence based medicine 2 Flashcards Preview

## Endocrine Week 4 2017/18 > 7: Evidence based medicine 2 > Flashcards

Flashcards in 7: Evidence based medicine 2 Deck (20)
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1
Q

What is a cohort study?

A

Comparisons of groups of a population who were a) exposed b) not exposed to a certain thing

e.g those exposed to radiation after Hiroshima/Nagasaki atomic bombings

2
Q

In a cohort study, you start with a population with different incidences of a thing and work (forwards / backwards) to figure out what caused this difference.

A

backwards

3
Q

In a cohort study, you can either

a) start with a population and follow them going forwards
b) go back and examine differences in a population

What are these types of study called?

A

Prospective cohort study

Retrospective cohort study

4
Q

A cohort study allows you to estimate the ___ of something occuring in a population.

A

risk

5
Q

In a cohort study, the population you have needs to be a ___ population.

A

general

otherwise you don’t know what’s typical/rare

6
Q

What size of population do you need to pick up rare diseases in a cohort study?

A

Large sample size

7
Q

What is relative risk?

A

Relative risk = Probability of event (incidence) when exposed / Probability of event (incidence) when not exposed

8
Q

What is relative risk also known as?

A

Risk ratio

9
Q

When there is no difference between two populations, the relative risk is _.

A

1

10
Q

If the risk ratio is < 1, the exposed population are (protected from / vulnerable to) the effect.

A

protected from

11
Q

If the risk ratio is > 1, the exposed population is (protected from / vulnerable to) the effect.

A

vulnerable to

12
Q

What is absolute risk?

A

Absolute risk = Risk in exposed group - Risk in non-exposed group

13
Q

What is a case control study?

A

Find two populations, one with the condition and one not

Take identical histories and compare them

Draw conclusions

14
Q

Cohort studies tend to go ___ in time while case-control studies go ___.

A

forwards

backwards

15
Q

Case control studies are good for studying ___ diseases.

A

rare

16
Q

What statistic is associated with case control studies?

A

Odds ratio

17
Q

How is an odds ratio calculated?

A

Odds ratio = Odds of event when exposed / Odds of event when not exposed

18
Q

An odds ratio of < 1 means that the risk is (lower / higher) in the exposed group.

A

lower

19
Q

An odds ratio of > 1 means that the risk in the exposed group is (lower / higher) than the risk in the non-exposed group.

A

higher

20
Q

Can causation be proved by a case-control study?

A

No

histories rely on memory