epidemiology

Question 1

infectious diseases terms

Answer 1

IP - symptoms
latency period - infectiousness
post - morbid period

Question 2

non infectious diseases terms

Answer 2

induction period - the period of time from causal
action until disease initiation
latent period - detection

Question 3

types of observational studies

Answer 3

analytical - control group
descriptive - no control group/comparison

Question 4

types of analytical studies

Answer 4

ecological - dealing with populations
cross sectional /prevelence
cohort
case control - retrospective

CCCE

Question 5

Descrtiptive studies explain

Answer 5

divided into case report (rare diseases)or case series ( larger group of patients with a single disease

:) provides detailed info so we get to know a lot about rare diseases, etiology , pathogenesis, etc
:( susceptible to bias
:( can’t directly transfer to clinical practice as there is a great level of uncertainty

Question 6

analytical studies describe

Answer 6

usually for testing hypothesis for the cause of a disease

Question 7

ecological studies

Answer 7

a type of analytical study
DEALING WITH POPULATIONS
TAKES PRE- EXISTING DATA
NO TIME DIMENSION - so we cannot prove a causal relationship
:( ecological fallacy

Question 8

prevalence studies /cross sectional

Answer 8

a type of analytical study

no time dimension
:) provides info about prevalence
:( not suitable for rare diseases

Question 9

case control

Answer 9

a type of analytical study
RETROSPECTIVE - looks back from the outcome of the disease to the exposure

• contains 2 or more groups (cases+ control)
• 3 steps 1. selection of cases 2. matching 3. elimination of bias

:) can be used for rare diseases (unlike cross sectional)
:) effieicnet in terms of time + resources
:) fast evaluation of chronic diseases

:( lack of representativeness
:( susceptible to selection + misclassification bias

Question 10

cohort studies

Answer 10

a type of analytical study
can be retrospective or prospective

example framigham heart study which is an example of retrospective

:) can detect a causal relationship
:) gives you info on incidence
:) can investigate several outcomes from 1 exposure
:( costly and time consuming
:( need large populations
:( ethical problems
:( following up on peoople can be difficult subjects may be lost!

Question 11

what can we divide epidemioligcal studies into

Answer 11

1. observational
2. experimental

Question 12

experimental studies

Answer 12

contains 2 groups, a control + experimental

examples :
randomised control trials
field trials
community trails

Question 13

Types of interventions:


Answer 13

Types of interventions:

Prophylactic - target on prevention (e.g. vaccines)
Diagnostic - target on evaluation of new diagnostic procedure
(e.g. new lab test to a gold standard, etc.)
Therapeutic - target on treatment (e.g. new drug)

Question 14

types of intervention trials

Answer 14

Community trials – a research study, carried out in a realistic community setting, that can involve an individual-level
intervention, a community-level intervention or both;
Clinical trials – a research study to test new methods of
screening, prevention, diagnosis or treatment of a disease,
carried out in hospital settings;
Laboratory experimental trials - a research study, usually
carried out on animals or tissues in laboratories.

Question 15

clinical trails

Answer 15

1. randomised control (gold standard for drug testing)

2,. non randomised

4 phases

phase 1- determine the non toxic dose on animals or healthy people - Is the drug actually safe?

phase 2 - clinical efficacy of the therapy

phase 3- monitor sides effects and COMPARE to the other treatments, and confirm the effectiveness

phase 4- any long term side effects?

Question 16

define natural history of disease

Answer 16

The course of a disease from its onset to its
resolutions (complete/partial recovery or death) is defined
as the natural history of a disease
- Natural history of diseases could be also classified into
two broad categories: acute and chronic. Acute diseases
(infections) have short natural histories. Chronic disea

Question 17

stages of natural history of disease

Answer 17

1. without a disease
   2.beginning of the disease
   3.asymptomatic stage
2. clinical diagnosis
3. disease development
4. exit of a disease

Question 18

types of ocntrols in intervential trials

Answer 18

1. placebo concurrent cortol grouo
2. dose related concurrent contolr group
3. active concurrent control group
   4.no tx concurrent controll group
4. historical control

Question 19

what is intervention

Answer 19

The exposure under investigation is applied by the investigator
Aim= To investigate a possible causal relationship by exposing one or more groups of patients to a factor (treatment) and compare results to one or more control groups that are unexposed to this factor.
Investigator decides which subjects are to be exposed and which not (closest analogy of lab. Experiment in epidemiology).

Question 20

aim of intervention trial

Answer 20

To investigate a possible causal relationship by exposing one or more groups of patients to a factor (treatment) and compare results to one or more control groups that are unexposed to this factor.