Transcript ORIGIN, GROWTH & DEVELOPMENT OF EPIDEMIOLOGY Dr. A. K. AVASARALA MBBS, M.D. PROFESSOR & HEAD DEPT OF COMMUNITY MEDICINE & EPIDEMIOLOGY PRATHIMA INSTITUTE OF MEDICAL SCIENCES, KARIMNAGAR, A.P. INDIA.

ORIGIN, GROWTH &
DEVELOPMENT OF
EPIDEMIOLOGY
Dr. A. K. AVASARALA MBBS, M.D.
PROFESSOR & HEAD DEPT OF
COMMUNITY MEDICINE &
EPIDEMIOLOGY
PRATHIMA INSTITUTE OF MEDICAL
SCIENCES, KARIMNAGAR, A.P.
INDIA : +91505417
[email protected]
EPIDEMIOLOGY TREE
DEVELOPMENT 1915 – till to date
GROWTH 1600-1905 AD
(GRAUNT TO FLETCHER)
ORIGIN
(HIPPOCRATIC TIMES ) 463 BC
EPIDEMIOLOGY TREE
•Has taken roots in
Hippocratic times
•Started growing in 17th century
•Lull in next two centuries due
to microbial era domination
•Developed and blossomed in
20th & 21st centuries.
ORIGIN
•SLIDES 4 TO 8
ORIGIN 2400 YEARS AGO
• HIPPOCRATES
planted the seed & the
tree of epidemiology has taken its roots in 463
BC, hence it is very old.
• His treatise on the role of environment in
causing the disease ‘Airs,Waters and Places’
is the first vivid epidemiological description
• Hence paradoxically, Epidemiology , is both
very old and very young science as it has
mostly developed recently.
HIPPOCRATES , THE FIRST EPIDEMIOLOGIST
“AIRS,WATERS & PLACES”
OF HIPPOCRATES
He stated in his famous treatise “On Airs, Waters,
Places,
that...”
Whoever
wishes to investigate medicine properly should
proceed thus: in the first place to consider the
seasons of the year, and what effects each of them
produces. Then the winds, the hot and the cold,
especially such as are common to all countries
and then such as are peculiar to each locality. In
the same manner. When one comes into a city to
which he is a stranger, he should consider its
situation, how it lies as to the winds and the rising
of the sun; for its influence is not the same
whether it lies to the north or the south, to the
HIS KEEN OBSERVATION &
APPLIED COMMONSENSE
HE ADVISED to search for factors causing
disease in
Air
(hot &cold winds)
Water (marshy, soft, hard, from rocky soil,
unfit for cooking)
places (naked without vegetation, deficient in
water, well watered, elevated and cold)
personal habits (drinking, excessive
eating, fond of exercise, and labor)
GROWTH
•SLIDES 9 TO 24
GROWTH NOURISHED BY
GRAUNT, SNOW, LIND, FLETCER, DOLL,
HILL, GOLDBERGER, ARR, JENNER
WITH THEIR
•PHILOSOPHICAL GENIUS
•KEEN OBSERVATION
•COUNTING OF CASES
•EXPLOITING THE NATURAL DISTURBANCES
OF HEALTH & DISEASE
•APPLIED COMMONSENSE, CREATIVE THINKING,
•GENERALIZATION CONCEPT
•SCIENTIFIC REASONING & VALIDITY
•COMPARABILITY AND ACCOUNTABILITY
EVOLUTIONARY PROCESS
IT HAS GROWN FROM
• PURE OBSERVATIONS &ADVICES FROM
HIPPOCRATES TO
• COUNTING OF CASES &ANALYSIS BY GRAUNT
& WILLIAM FARR
•
•
NATURAL EXPERIMENTS BY JOHN SNOW
TRUE EXPERIMENTS
BY LIND, JENNER, FLETCHER, DOLL & HILL &
OTHER EPIDEMIOLOGISTS IN THE LAST TWO
CENTURIES
FIVE PHAGES OF GROWTH
• First phage:
Investigation of specific diseases- efforts
were concentrated to investigate cholera,
pellagra, scurvy, beri beri, lung cancers ( e.g.
Snow’s cholera, Fletcher’s beri beri, Lind’s
scurvy experiments)
• Second phage (turning point):
Introduction of randomization ,blinding
and controlling to eliminate bias and enhance
the quality of methods of investigation and
make them systematic without errors.
Credit of stimulus goes to DOLL & HILL
experiments at this stage.
GROWTH 17TH TO 19TH CENTURIES
1600AD
1747
1796
1880
JOHN GRAUNT
LONDON BILLS OF
MORTALITY ANALYSIS
JAMES LIND
CITRUS FRUITS TO CURE
SCURVY IN SAILORS
EDWARD JENNER
W.H .FROST
1889
WILLIAM FARR
1849
1881
1900
TRIAL WITH COWPOX
VACCINE
EXPLAINED INTERPLAY OF
FACTORS CAUSING
EPIDEMICS
ANALYSIS OF VITAL STATISTICS
& EFFECTS OF IMPRISONMENT
IN PRISONERS
JOHN SNOW
NATURAL EXPERIMENT
ON LONDON CHOLERA
FINLAY
MOSQUITO BORNE NATURE
OF YELLOW FEVER
BRADFORD HILL. A
CONCEPT OF RANDOMIZATION
&SMOKING AND LUNG CANCER
EXPERIMENTS
JOHN GRAUNT’S CONTRIBUTION (1600AD)
Graunt in 17th century counted the mortality
rates for 37 years in London from the Bills of
mortality and found
1) constancy in the ratio from male to female in
births and deaths.
2) age specific mortality is higher among males than
in females.
3) seasonal fluctuations in deaths from various
causes.
4) measured the ebb and flow of various diseases
and the host factors.
5) suggested quantitative methods to test the
hypothesis of this variations.
• John
JAMES LIND’S CONTRIBUTION (1747)
JAMES LIND (1747) of 18 th century made notable
contributions to the growth of epidemiology.
James Lind, a naval surgeon, conducted a true
experiment on his 12 soldiers suffering from
scurvy. He made them into six pairs and
supplemented each pair’s diet with 1) vinegar,
2) mixture of nutmeg, garlic, mustard and
tamarind in barley water, 3) elixir vitriol, 4) sea
water, 5) cider, and 6) two oranges and one lemon
for six days. Limeys, the pair which has taken
oranges and lemons showed improvement from
Scurvy and it was a proved that fresh fruits
relieved scurvy. This is a true experiment he
carried out where in he deliberately modified the
diets to get the desired information.
EDWARD JENNER’S CONTRIBUTION (1796)
•EDWARD JENNER(1796), an English
Physician, was the first person to
immunize against smallpox with cowpox
vaccine. He accidentally found that
milkmaids infected with cowpox were
immune to smallpox. Then he inoculated
a boy of 10 years of age with mild live
cowpox vaccine to immunize against
smallpox and over the succeeding two
years he successfully inoculated 22
more persons thus paved the way for
preventive medicine and epidemiology.
WILLIAM FARR’S CONTRIBUTION (1889)
William Farr, a physician of the 19th century,
working as the first in Registrar General office of
England & Wales, analyzed the vital statistics for
40 years and made valuable observations with
regard to the then health situation and
recommended their application for public health
improvement. He found high mortality in certain
occupations like miners. He studied the health of
prisoners and found, while 8 only died due to
executions, 52 died of imprisonment. He also
found that fluctuations in marriage rates depend
upon price of bread, cholera, population
movements and person’s monetary value. His
findings paved the way for proper health planning
and policies and thus fostered epidemiology.
JOHN SNOW’S CONTRIBUTION (1849)
John Snow (1849) is a physician for Queen
Victoria and great epidemiologist. He is a
philosophical genius because he could control
cholera in London even before the causative
organism was discovered and found out how
cholera spreads. His genius showed in his
meticulous and scientific way of conducting the
natural experiment to prove his hypothesis that
contaminated water is the vehicle for the cholera
spread. He thoughtfully considered all other
causes that may confound his hypothesis and
wisely neutralized them. He had seen that no
difference whatever existed, either in the houses
or the people receiving water supply of two water
companies, or in any physical conditions with
which they are surrendered.
SNOW ‘S WORDS ABOUT HIS EXPERIMENT
The intermixing of the water supply of the
Southwark and Vauxhall Company with that of the
Lamberth Company, over an extensive part of
London, admitted of the subject being sifted in
such a way as to yield the most incontrovertible
proof on one side or the other. In the subdistricts enumerated in the above table [Table in
this chapter] as being supplied by both
Companies, the mixing of the supply is of the
most intimate kind. The pipes of each Company
go down all the streets, and into nearly all the
courts and alleys. A few houses are supplied by
one Company and a few by the other, according
to the decision of the owner or occupier at that
time when the Water Companies were in active
competition.
GREATNESS OF SNOW’S EXPERIMENT
•The experiment, too, was on the grandest
scale. No fewer than three hundred
thousand people of both sexes, of every
age and occupation, and of every rank and
station, from gentlefolks down to the very
poor were divided in to two groups without
their choice, and, in most cases, without
their knowledge; one group being supplied
with water containing the sewage of
London, and, amongst it, whatever might
have come from the cholera patients, the
other groups having water quite free from
such impurity.
AUSTIN BRADFORD HILL’S CONTRIBUTION
(1900)
AUSTIN BRADFORD HILL, in mid 1900, gifted to the
concept of Randomization for the epidemiological
growth. It enhanced the value of all the
experiments that were carried in later years as it
eliminates the biases (systematic errors) and
neutralizes all the known and unknown confounders
in the studies. In the present century, any scientific
experiment, test, drug, method is accepted only
after it is subjected to randomized controlled trials.
All present clinical trials are randomized ones and
as the randomization made the procedure more
scientific, it is carried out first in any study. His
experiments in 1954, to prove causal relationship
between smoking and lung cancer really speeded
up the growth of epidemiology.
FLETCHER’S CONTRIBUTION (1905)
FLETCHER(1905) studied Beriberi that
occurred in lunatics in mental asylum in Kuala
Lumpur (Malaysia) and proved that it is due to
nutritional deficiency and not a place disease
as suggested by Sir Patrick Manson. In this
true experiment, he allocated the lunatics into
two groups, one to receive parboiled rice and
other to get Siamese rice (polished one).
Siamese rice group had higher number of
deaths when compared to cured parboiled rice
group. He later changed the wards and found
the same results thereby disproving that it is a
place disease.
FLETCHER EXPERIMENT
•By June 20th many cases of beri-beri had occurred
amongst the patients in the east ward who were
eating uncured rice, whereas no cases had
occurred in the west ward, the inmates of which
were dieted on cured (Indian) rice.
•In view of the theory so strongly advocated by Sir
Patrick Manson that beri-beri is a place disease, it
was thought possible that the eastward was
infected. Therefore on June 20th the patients were
a, those on uncured rice being moved to the
westward and those on cured (Indian) rice
transferred to the east. From June 20th to Dec. 31st
no beri -beri developed among the patients on
cured rice although they were living in a ward
where beri-beri had been rife amongst the lunatics
who were fed on uncured (Siamese) rice.
GOLDBERGER’S CONTRIBUTION (1915)
GOLDBERGER JOSEPH (1915) proved
that Pellagra is not an infectious disease
as it was thought earlier, but a
nutritional deficiency state. He induced
pellagra experimentally by providing a
diet deficient in Nicotinic acid and
conducted studies in several rural
communities and in institutions to
demonstrate conclusively that pellagra
was a dietary deficiency disease.
DEVELOPMENT
•SLIDES 25 TO 32
INTERNATIONAL CONTRIBUTION
FOR DEVELOPMENT
•
•
•
•
•
WORLD HEALTH ORGANIZATION
UNICEF
USAID
PRIVATE FUNDING AGENCIES
GLOBAL NETWORK OF NONGOVERNMENTAL ORGANIZATIONS
• WORLD WIDE WEB
(INTERNET EPIDEMIOLOGY)
20 TH CENTURY DEVELOPMENT
1905
1915
Gold Berger & Wheeler
1942
Kinsley & Hemphill
1946
1948
1952
1954
1955
1969
1971
PARBOILED RICE FOR TREATING
BERIBERI IN LUNATICS
INDUCED PELLAGRA BY
DIETARY MODIFICATIONS
OXYGEN THERAPY &
RETROLENTAL FIBROPLASIA
Fletcher
WHOOPING COUGH VACCINE
TRIAL
Medical Research Council (UK)
CORONARY HEART DISEASE
Framingham Heart Study
Doll
A.B. Hill
Brown & Hill
Doll
SMOKING & LUNG CANCER
SMOKING & LUNG CANCER
LEUKEMIA DUE TO IRRADIATION
TREATMENT FOR ANKYLOSING
SPONDYLITIS
ORAL CONTACEPTIVES & HEALTH
Boston Hospital Study
WHO CLOFIBRATE CLINICAL TRIAL,
20th OSLO STUDY, NORTH KARELIA PROJECT,
cen- MRFIT(USA), STANFORD THREE COMMUNITY
STUDY, BETA BLOCKERS IN MYOCARDIAL
tury INFARCTION, ASPIRIN STUDY,
ADENOCARCINOMA OF VAGINA IN
YOUNG WOMEN
TO REDUCE
CARDIOVASCULAR
MORTALITY
FEW 21ST CENTURY
DEVELOPMENTAL STUDIES
ANTENATAL FOLATE
SUPPLEMENTATION
BETA CAROTENE IN
DIET
ARSENIC STUDY
TO REDUCE NEURAL
TUBE DEFECTS
IN URANIUM WORKERS
FOR LUNG CANCERS
POLYVINYL CHLORIDE
ANGIOSARCOMA OF
LIVER
TO PREVENT
CANCERS
IN HUMAN CANCERS
21ST CENTURY DEVELOPMENT
RANDOMIZED
CONTROLLED
TRIALS ACCEPTED
BY WORLD AS
SCIENTIFIC
NECESSITY
MULTICENTRIC
TRIALS ARE
FOLLOWED BY THE
WORLD TO PROVE
THE CONSITENCY
COLLOBORATIVE
APPROACH IS
ACCEPTED BY
WORLD AS MOST
FEASIBLE WAY OF
DOING THINGS
WORLD WIDE WEB
(GLOBAL HEALTH
NETWORK)
SUPERCOURSE AIMED
AT UNIVERSAL
DISTRIBUTION OF
EPIDEMIOLOGICAL
INFORMATION
SCOPE FOR FURTHER DEVELOPMENT
• VERY VAST BECAUSE EPIDEMIOLOGY ENGAGES THE
MOST HONEST SERVINGMEN OF VON KIPPLING VERY
WISELY.
• ANY ASPECT OF LIVES OF THE POPUPATION CAN BE
QUESTIONED WITH “WHY, WHAT, WHEN, WHERE, WHOM
AND HOW. THERE IS NO RESTRICTION FOR ITS
TRANSGRESSION FROM PAEDIATRICS TO GERIATRICS.
• INTERNATIONAL ACCEPTANCE AND DEPENDENCE ON
EPIDEMIOLOGY TO MANAGE AND SOLVE HEALTH
PROBLEMS MAKES ITS DEVELOPMENT MANDATORY
NOW AND IN NEAR FUTURE.
• WORLD WIDE WEB (GLOBAL HEALTH NETWORK&
SUPERCOURSE) WITH ITS EXTENSIVE NETWORK
ENRICHES THE QUALITY AND QUANTITY OF
EPIDEMIOLOGICAL INFORMATION TO THE PUBLIC WHO
WILL IN TURN APPRECIATE, ACCEPT, GET BENIFITTED
AND NATURALLY PROMOTE ITS GROWTH &
DEVELOPMENT.
SUMMARY & CONCLUSIONS
•NO ONE CAN CONCLUDE OR SUMMARISE AS
EPIDEMIOLOGICAL GROWTH &DEVELOPMENT AS IT IS
A PHILOSOPHICAL STUDY OF A HEALTH PROBLEM.
HENCE WE CANNOT PUT A FULLSTOP ANYWHERE FOR
EPIDEMIOLOGICAL GROWTH. IT WILL BE GROWING IN
ALL DIRECTIONS AS LONG AS APPLIED
COMMONSENSE IS PREVAILINGLE WITH
EPIDEMIOLOGISTS AND PUBLIC.
•GREAT BEGINNING : HIPPOCRATES ADVISED,
GRAUNT AND FARR COUNTED AND ANLYSED THE
CASES, SNOW EXPLOITED & EXPERIMENTED THE
NATURAL EVENT TO TKNOW HOW ITS SPREADS.
LIND, FLETCHER AND OTHERS EXPERIMENTED AND
HENCE THEY BECAME THE FORERUNNERS OF
EPIDEMIOLOGY AND PAVED THE WAY FOR OTHERS AND
TAUGHT OTHERS WHAT IS EPIDEMIOLOGY AND HOW IT
SHOULD BE PRACTICED.
REFERENCES
•Brian Mac Mahan -Epidemiologyprinciples & methods
• Roger Detels, James Mc EvenOxford Text Book of Public Health
•Maxcy-Rosenau-Last, Public
Health &Preventive medicine
•Brett & Cassens - Public Health
Medicine, National Student Series.