Experimental epidemiology involves manipulating study factors and conditions to test interventions and their effects on disease. There are two main types: randomized controlled trials (RCTs) and non-randomized trials. RCTs randomly assign subjects to treatment and control groups to reduce bias when testing new interventions. They involve developing a study protocol, selecting and randomizing populations, implementing interventions, follow-up, and assessing outcomes. Non-randomized trials do not randomly assign subjects and are used when RCTs are not possible, such as when interventions apply to groups. Examples include uncontrolled trials with no comparison and natural experiments that mimic real-world circumstances. Experimental epidemiology aims to identify disease causes and evaluate prevention and treatment effectiveness.

1. Experimental
Epidemiology
Presented to: Presented
by:
Dr. Anjalatchi Ma’am Ms. Shailja
Singh
MSC(N),MD(AM),MBA(HA) MHA 2nd sem.
Era university Era
university

2. ABBREVIATIONS
RCT- Randomized Controlled Trials
WHO-World health organization

3. CONTENTS
 Introduction
 Aims
 Experimental studies part
 Advantages & disadvantages
 James Lind experiment
 Types of Experimental Study
 RCT – process
 Non-RCT .
 Conclusion
 Bibliography
 Questionnaires

4. Experimental Epidemiology
 The idea design to use in epidemiological research settings is an
experimental epidemiology.
 The experimental epidemiology is a modern epidemiology method .
 1920s experimental epidemiology meant study of epidemics among
colonies of experimental animals such as rat & mice.

5. Aims of experimental studies
 To provide scientific proof of etiological factors which may permit
modification or control of disease.
 To provide a method of measuring the effectiveness and efficiency of
health services for the prevention ,control and treatment of disease
and improve the health of the community.

6. Experimental studies derived in the two part:-
1. Animal experiments
 Animals have played important role in men’s quest for knowledge
about himself.
 Animal studies have contributed to all branches of medicine.
 To confirm etiological hypothesis and study pathogenic phenomena .
 Testing efficacy of preventive and therapeutic measures such as
vaccines or drugs.
 Completing the natural history of disease.

7. Animal experiment continued..
Advantage
 Can be bred easily .
 Multiple rapidly.
 Genetic experiments.
Disadvantage
 Not all human disease can be
reproduced in animals.
 All calculations draws may not
strictly apply to human.

8. 2.Human experiments
 Human experiments will always be needed to investigate disease
etiology and evaluate the preventive and therapeutic measures .

9. James Lind 1747 , planned trials
 He took 12 patients in the scurvy on board the Salisbury at sea.
 The cases were as similar as they lay together in one place and had one diet
common to them all.
 Two of these were ordered a quart of cider per day .
 Two others took 25 gutts of elixir vitriol , two other took 2 spoone vinegar , two
were put under a course of sea water , two other had two oranges and one
lemon given them each day,two other took the bigness nutmeg .

10.  The most sudden and visible good effects were perceived from the
use of oranges and lemons, one of those who had taken them being at
the end of 6 days fit for duty. The other was appointed nurse to the rest
of the sick.

11. Experimental Studies are two types –
1. Randomised controlled trials ( Clinical trials or investigation
Study)
2. Non randomised ( uncontrolled trials or natural experiments)

12. Randomised controlled trials:-
 RCT is a type of scientific experiment (clinical trials ) Or investigation study.
 It is help to reduce certain sources of bias when testing the
effectiveness of new treatments; this is accomplished by randomly
allocating subjects to two or more groups, treating them differently,
and then comparing them with respect to a measured response.
"It permits the use of probability theory to express the likelihood that any difference in outcome
between treatment groups merely indicates chance."

13. Basic steps in RCT -
1. Drawing up a protocol .
2. Selecting reference and experimental Population.
3. Randomization.
4. Manipulation or Intervention
5. Follow up
6. Assessment of Outcome.

14. Non randomised trials :-
 Also known as Quasi-Experimental Designs.
 It is a type of research in which the investigator manipulates the study factor
but does not assign individual subjects randomly to the exposed & non-
exposed groups.
 These are designed as it is always not possible for ethical, administrative and
other reasons to resort to a RCT.
 Some preventive measures apply only to groups or community-wide basis.
When disease RCT require follow-up of thousands of People for a decade Or
more .

15. Examples of non randomised trials:-
Uncontrolled trials-
 Trials with no comparision group .
 useful to know whether specific therapy is valuable for particular
disease to determine the appropriate dose , to investigate adverse
reaction .

16. Natural experiments:-
 Where experimental studies are not possible in human being , some natural
circumstances mimics as experiment.
e.g.
 Smokers and non smokers – lung cancer
 john snow discovery- Cholera- water born disease.

17. SUMMARY:-
 Experimental or intervention studies - conditions in which study is
carried out are under the direct control of the investigator. Thus,
experimental studies involve some action, intervention or manipulation.
 Randomized controlled trials provide the best evidence of the efficacy of
medical interventions but they are not immune to bias.

18. Conclusion
 I hope you all understand the introduction of
experimental epidemiological methods, types and
process.

19. Bibliography
 Park K. Textbook of Preventive and Social Medicine. 21st edition. Pg. No. 88- 91 .
 Surykanta. Community and preventive medicine. 4th edition. Pg. No. 266-268.
 Google.com

20. Questionnaire
1. What is experimental epidemiology
2. Aims of experimental epidemiology
3. Advantages &disadvantages of experimental epidemiology
4. Types of experimental epidemiology .

21. Thank you...