Identifying disease

Question 1

how can a case studies be used to identify cause for a disease

Answer 1

if multiple case studies report similar findings

Question 2

how can a case-control studies be used to identify cause for a disease

Answer 2

if certain exposures are significantly more common in the cases group then it can reassumed that that exposure is the potential cause of the disease

Question 3

how can a cohort studies be used to identify cause for a disease

Answer 3

exposures which are more common in those who develop the disease could be identified as the potential cause of a disease

Question 4

how can a RCT study be used to identify cause for a disease

Answer 4

e. g. if the new treatment targets a specific protein (e.g. TK in CML) and the drug caused the slowing in progression of the disease- then the protein could be concluded as the cause of CML
- -> due to RCTs reducing the influence of confounding

Question 5

Kochs postulates

Answer 5

1) disease causing agent must be present in all of those with the disease
2) disease causing agent must be purified and cultured
3) disease causing agent must cause disease when given to healthy
4) disease causing agent must be preisolated and confirmed to be the same agent

Question 6

viral DNA will never be longer than

Answer 6

300bp

Question 7

how can observational studies generate hypotheses

Answer 7

by recording exposures which seem to be more prevalent in certain diseases
e.g. observing that most individuals with lung cancer smoke/ have smoked

Question 8

how can these hypotheses be tested

Answer 8

using trials

Question 9

why would you use a cohort over a case-control

Answer 9

the best information about the causation of disease, because you follow persons from exposure to the occurrence of the disease.

Question 10

cohort studies work well for

Answer 10

rare exposures

Question 11

case-controls are sometimes better than cohorts since

Answer 11

• no follow up period- therefore quick and cheap

- good for rare diseases, but not rarer causes

Question 12

case-controls are more prone to

Answer 12

bias than cohort

• cant match groups
• no randomisation

Question 13

often use observational studies

Answer 13

to justify interventional studies

Question 14

generally accepted that observational studies can..

Answer 14

distinguish associations between events but cannot conclude that one event causes another