epidemiology and biostatic study

8/10/2019 Epidemiology and Biostatic Study

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Introduction to Epidemiology


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At the end of this lesson, students are able to:

1. State Father of Occupational Medicine, Father of Immunology,

Father of Modern Epidemiology and Typhoid Mary

2. Define epidemiology

3. State the uses of epidemiology

4. Describe the natural history of disease

5. Illustrate the epidemiologic triangle


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LESSON OUTLINE

1. History / evolution of epidemiology

2. Terminology in Epidemiology

3. Uses of epidemiology

4. Natural history of disease

5. Epidemiologic triangle


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History / Evolution of

Epidemiology


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Father Of Occupational

Medicine

Occupational diseases

What is your occupation?

Bernardino Ramazzini

(1633 - 1714) Italy


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Edward Jenner (17491823) England

Father of Immunology

Pioneer of smallpox vaccine

Saved more lives than the work of

any other man"

In 1979, the World HealthOrganization declared smallpox an

eradicated disease


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John Snow (18131858) England

Father of Modern Epidemiology

Mapping of cholera cases in East

London during cholera epidemic in 1854

Traced source to a single well on Broad

Street that had been contaminated by

sewage


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Source of

outbreak

Dot / Spot Map


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Known as Typhoid Mary

Asymptomatic / healthy carrier Cook

Typhoid fever

Mary Mallon (18691938) US


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Typhoid Mary

Mary Mallon, a cook responsible for 1904 typhoid fever epidemic

When source of disease was traced, Mary had disappearedonly to

resurface in 1907 when more cases occurred

Again Mary fled, but authorities led by George Soper, caught her and

had her quarantinedon North Brother Island

In 1910 the health department released her on condition that shenever accept employment involving the handling of food

Four years later, Soper began looking for Mary again when two new

epidemics broke out; Mary had worked as a cookat both places

She was found and returned to North Brother Island, where sheremained the rest of her life until a paralytic stroke in 1932 led to her

slow death, six years later


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Statistics & Biostatistics

Statisticsthe science and art of dealing with variation ofdata in order to obtain reliable results and conclusions

Biostatisticsthe application of statistics to problems in

the biological sciences, health and medicine

Eg:

Computing age-adjusted cancer incidence rates to

determine trends over time and locality

Calculating statistical measures of the risk of developingbrain tumors following cell phone use

Quantifying the relationship between use of Cox-2

inhibitors and quality of life


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Epidemiology is a word with Greek origins:

epi, meaning on, upon or befall,

demos, meaning people, and

logos, meaning the study of.

The study of what is upon the people

Epidemiology


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The study of the distribution and

determinants of health-relatedstates

or events in specified populations,and the application of this study to

the controlof health problems

(WHO)

Definition of Epidemiology


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Distr ibut ion

the frequency and pattern of health events

in a population.

Frequencyrefers to the numberof health

events


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Patternrefers to the occurrence of health-

related events by time, place, and person.

Time patterns may be annual, seasonal, weekly,

daily, hourly, that may influence health events

occurrence.

Place patterns include geographic variation,

urban/rural differences, and location of work sites or

schools.

Personal characteristics include demographic

factors such as age, sex, marital status,

socioeconomic status, behaviors and environmental

exposures.


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Frequency & Pattern


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Determinants

Are the causes and factors that influence the

occurrence of health-related events.

Eg. Eating contaminated food causes

diarrhea


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Health-related events

Anything that affects the well-beingof a population.

disease epidemic

endemic diseases

chronic diseases

occupational health & safetyinjury, disease

environmental healthwater supply, foods

behaviorslack of exercise, unhealthy eating,

smoking


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1. To determine the etiologicalor causal factorsofdiseases

2. To determine the frequency and distributionof a diseasein a community

3. To evaluate preventive,therapeuticand interventionactivities

4. To develop publichealth policies and regulations


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5. To solve epidemics/outbreaks.

6. To predictdisease occurrence, impact and distribution in

a community.

7. Surveillancefor new disease and changes in old ones.

8. To plan current and future health care needs.


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It is important to know about the natural history of a disease to help

prevent, treat and control a disease

It is the description of the progression of a disease from the first sign

or manifestation of the disease until recovery or death

Incubation Period

EndingBeginning


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The Triangle has three components:

Agent, or microbe that causesthe disease (the what

of the Triangle)

Host, or organism harbouringthe disease or carrier

(the who of the Triangle)

Environment, or those external factors that cause or

allow disease transmission(the where of the Triangle)


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It is the model of infectious disease causation.

It has 3 components: an external agent, a susceptiblehostand environmentthat brings the agent and the

host together. Disease has been classically described as the result of

an epidemiologic triangle.

Infectious diseases result from the interaction of agent,

host, and environment


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1. US Department of Health and Human Services, Center forDisease Control and Prevention, 2012. Principles of

Epidemiology in Public Health Practice,3rdEdition, Atlanta.

2. R. Bonita, R. Beaglehole and T. Kjellstrom, 2006. Basic

Epidemiology, 2nd

Edition, World Health Organization,Geneva.

3. Karuthan C. and Krishnakumari K., 2009. Biostatistics for the

Health Sciences. Mc Graw Hill.

epidemiology and biostatic study

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