What is epidemiology
● Study of how disease is distributed in populations and the factors that influence or
determine this distribution
● The premise underlying epidemiology is that disease, illness, ill health and excellent
health are not randomly distributed in human populations
● Not random study
○ Why is it common is some region, why does it change, it is not chance, some
underlying factors that lead to development of illness
● Epidemiology is a foundational discipline of public health and clinical medicine
Objectives of Epidemiology
1. Identify disease risk factors or etiologic research
a. Studying cause of disease
2. Determine extent of disease in community
a. Where is disease more common, who will be ill, change in rate of disease
3. Natural history and prognosis of disease
a. What are the consequences, quality of life, mortality, health of infected individuals
4. Disease prevention/treatment evaluation
a. Randomized trial, new treatment
5. Public policy foundation
Changing Patterns of Community Health Problem
● Diseases are not static but change over time
○ COVID relatively new from SARS. Viral infection that causes minor illness to
sever respiratory(disease are not static)
● Cholera is an ancient disease which was limited to parts of India prior to the 19th
Century
● Cholera is a diarrhoeal disease that can kill within hours if left untreated
● Spread globally starting around 1817
● Became a serious health problem in Europe by the 1830
○ European colonized and spread across the globe
Followed by war, economic breakdown, anything distrupts access to clean water will cause
Cholera outbreak. By time to time, still active
, Leading cause of death changed overtime. From pneumonia and influenza to heart disease.
The name of the disease could also change over time (senility= Alzheimer)
Controllable/curable disease
People living longer, heart and cancer increased than before
Infectious disease used to be more common now more chronic disease thrives
Life expectancy had increased overtime but…
● Study of how disease is distributed in populations and the factors that influence or
determine this distribution
● The premise underlying epidemiology is that disease, illness, ill health and excellent
health are not randomly distributed in human populations
● Not random study
○ Why is it common is some region, why does it change, it is not chance, some
underlying factors that lead to development of illness
● Epidemiology is a foundational discipline of public health and clinical medicine
Objectives of Epidemiology
1. Identify disease risk factors or etiologic research
a. Studying cause of disease
2. Determine extent of disease in community
a. Where is disease more common, who will be ill, change in rate of disease
3. Natural history and prognosis of disease
a. What are the consequences, quality of life, mortality, health of infected individuals
4. Disease prevention/treatment evaluation
a. Randomized trial, new treatment
5. Public policy foundation
Changing Patterns of Community Health Problem
● Diseases are not static but change over time
○ COVID relatively new from SARS. Viral infection that causes minor illness to
sever respiratory(disease are not static)
● Cholera is an ancient disease which was limited to parts of India prior to the 19th
Century
● Cholera is a diarrhoeal disease that can kill within hours if left untreated
● Spread globally starting around 1817
● Became a serious health problem in Europe by the 1830
○ European colonized and spread across the globe
Followed by war, economic breakdown, anything distrupts access to clean water will cause
Cholera outbreak. By time to time, still active
, Leading cause of death changed overtime. From pneumonia and influenza to heart disease.
The name of the disease could also change over time (senility= Alzheimer)
Controllable/curable disease
People living longer, heart and cancer increased than before
Infectious disease used to be more common now more chronic disease thrives
Life expectancy had increased overtime but…
