Epidemiology is the study and analysis of the patterns, causes, and effects of health and disease conditions in defined populations. It is the cornerstone of public health, and shapes policy decisions and evidence-based practice by identifying risk factors for disease and targets for preventive healthcare. Epidemiologists help with study design, collection, and statistical analysis of data, amend interpretation and dissemination of results (including peer review and occasional systematic review). Epidemiology has helped develop methodology used in clinical research, public health studies, and, to a lesser extent, basic research in the biological sciences. Epidemiology is the study of the distribution and determinants of health- related states or events in specified populations, and the application of this study to control of health problems
This are the two type of the epidemiology :
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| (source: www.slideshare.net) |
• Hippocrates wrote On Airs, Waters, and Places in 400 BC.
• He suggested that disease might be associated with the physical environment instead of supernatural viewpoint.
• He suggested that environmental and host factors (e.g. behaviors) might influence the development of disease.
John Graunt: Mortality Counts
• John Graunt, in 1662, published Natural and Political Observations Made upon the Bills of Mortality.
• His contributions:
• Recorded seasonal variations in births and deaths.
• Showed excess male over female differences in mortality.
• Known as the “Columbus” of biostatistics.
John Snow: Natural Experiment
• John Snow was an English physician and anesthesiologist. He investigated a
cholera outbreak that occurred during the mid-19th century in Broad Street, Golden Square, London.
• Linked the cholera epidemic to contaminated water supplies. Used a spot map of cases and tabulation of fatal attacks and deaths.
Snow’s Natural Experiment
• 2 different water companies supplied water from Thames River to the public.
• The Lambeth Company moved its source of water to a less polluted portion of the river.
• Snow noted that during the next cholera outbreak those served by the Lambeth Company had fewer cases of cholera.
Types of Epidemiology
• Descriptive epidemiology – description of disease occurrence in population according to person, place and time.
• Analytic epidemiology – examines causal (etiologic) hypotheses regarding the association between exposures and health conditions.
Analytic epidemiology
The epidemiologic triangle or triad is the traditional model of infectious disease causation.
Epid. Triangle (agent)
• Agent, an entity necessary to cause disease in a susceptible host
• For examples:-
• biological (bacteria, virus, parasites)
• physical (radiation, physical force)
• chemical (pollutants, drugs)
• nutrients (nutritional deficiency)
Epid. Triangle (host)
• Host are intrinsic factors that influence an individual’s exposure, susceptibility, or response to a causative agent.
• Age, race, sex, SES status, immunity, and behaviors (smoking, drug abuse, lifestyle, sexual practices and contraception, eating habits) are justsome of the factors which affect a person’s likelihood of exposure.
Epid. Triangle (environment)
• Environment, influence interaction between agent & host
• Environmental factors include physical factors such as geology, climate, and physical (e.g. nursing home, hospital); biologic factors (insects); SES factors (income, crowding, sanitation, and the availability of health services).
Epid. Triangle (environment)
• Environment, influence interaction between agent & host
• Environmental factors include physical factors such as geology, climate, and
physical (e.g. nursing home, hospital); biologic factors (insects); SES factors (income, crowding, sanitation, and the availability of health services).
Uses of Epidemiology
• To determine, describe, and report on the natural course of disease, disability,
injury, and death.
• To aid in the planning and development of health services and programs
• To provide administrative and planning data
• Currently, natural experiments may be the result of legislation, policy changes or environmental interventions.
Summary
Descriptive Epid.
• Person, place & time
• Demographic distribution
• Geographic distribution
• Seasonal patterns etc
• Frequency of disease patterns
Analytic Epid.
• Built around the
• looking for analysis of the relationship between two items
• Exposures
• Effects (disease) determinants or possible causes of disease
Reference
-https://www.youtube.com/watch?v=sdFYHSxq_qo
-https://en.wikipedia.org/wiki/Epidemiology
-noted that had been given from my lecterur Sir Mohd Azim Jalil Bin Mustafa
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