Epidemiology - an introduction

The “Study of the people”

Epidemiology

• Is the basic science of preventive & social med

• It began with Adam & eve both tried to investigate the qualities of “forbidden fruit”

• Derived from word epidemicepi = among demos= peoplelogos= study

Epidemiology has been defined as

“ means of learning or asking questions.. and getting answers ,that lead to further questions”

• Epidemiological information is used

to plan strategies to prevent illness

following question can be asked in Epidemiology

What is the event/ problem ?

What is the magnitude of problem?

When did it happen ?

Where did it happen?

Who are affected ?

Why did it happen?

John M. Last in 1988 defined-

• Epidemiology “The Study of the distribution and determinants of health related state or events in specified populations,

And

application of this study to control & prevent the health problems”

Modern epidemiology deals with “facts of life”

What is health related events?

• Are all the conditions of spectrum of health such as---------

• disease,

• injury,

• disability and

• death among the population.

What is distribution?

• It is pattern of occurrence of disease with reference to-

Time .

Place.

Person

Study distribution helps-

• This helps to study trend of diseases.

• Helps to know the magnitude of problem.

• Gives clues of etiology, mode of transmission.

• Helps to formulate etiological hypothesis.

(Descriptive epidemiology)

What is determinants ?

• This is etiological risk factors.

like…..age, sex, obesity, occupation…

• Study helps to test etiological hypothesis.

(this is analytical epidemiology)

What is frequency?

• Means measuring the magnitude /extent of health problems in terms of morbidity and mortality rates,.. that helps for comparison.

• Morbidity rates- Incidence & prevalence.

• Mortality rates- Rates, Ratio, and proportion.

Application of epidemiology-

• To search causes of diseases.

• To determine probability/risk of disease.

• To describe health status of population.

• To control the diseases.

• To plan health programs.

• To evaluate health programs.

Objectives of epidemiology-

• To reduce incidence & prevalence of diseases.

• It help to eradicate/ eliminate the diseases.

• To promote health and well being of society.

Epidemiological approach-

• What is the event?

• When & where did the disease occur?

• Who are affected?

• What is the extent of problem?

• What is to be done to reduce the problem?

• Why did it occur?

• How can it be prevented in future?