Labs

Public Health

Public health is in the news everyday.

Public health protects people safe and healthy.

…modern sanitation was one of the greatest public health accomplishments of the late 19th and early 20th centuries.

Public health keeps entire populations healthy. When it fails, entire populations suffer.

Fluoridation is a major public health accomplishment.

Public health keeps food safe.

Public health tracks down the causes of disease outbreaks and stops them.

Folic acid supplementation is an important public health measure to prevent birth defects.

Public health prevents childhood disease and death.

Safety belts save more than 12,000 American lives annually.

Child safety seats reduce the risk of death by about 70% for infants and by about 55% for toddlers ages 1 to 4.

Bicycle helmets reduce the risk of serious head injury by as much as 85%.

Public health reduces tobacco use.

Public health keeps restaurant food safe.

Public health is preparing for whatever comes next.

Many people and many organizations help keep communities healthy.

What is Epidemiology?

Greek (English)


epi (among)

demos (people)

logy (study)

What is Epidemiology?

The study of the distribution and determinants of health and disease related states in populations, and the application of this study to control health problems.
“epidemiology’s full value is achieved only when its contributions are placed in the context of public health action, resulting in a healthier populace.”
“the product of [epidemiology] is research and information and not public health action and implementation”.

The “demi” in Epidemiology

Understanding population dynamics is crucial to epidemiology.

Demography = the study of population dynamics including fertility, mortality and migration
denominator…denominator…denominator…denominator…denominator…denominator…

Comparing rates between two different populations

What is your guess regarding the incidence of HIV/AIDS in Kenya compared to Denmark?

Comparing rates between two different populations

Crude Incidence of HIV/AIDS, 2005
Rate / 1,000
Kenya data from UNAIDS/WHO, Denmark data from UNICEF

Comparing rates between two different populations

Age (years)
% of
cases
HIV/AIDS by Age
(from CDC, U.S. 2001-04)

Potential problems in interpretation of rates over time

Numerator
diagnostic abilities
diagnostic criteria
reporting completeness
payment schemes (affecting items above)
others . . .
Denominator
census methods for classification
age misclassification
removal of persons at risk
cohort effects (changes in exposure/prognosis or other confounding variables over time)
others . . .


Age / Period / Cohort Effects

Age / Period / Cohort Effects

Demography
It is the science that studies human population

Demos

population
Graphy
picture
Elements of demography:
Size
Composition
Distribution

Fertility

Mortality
Migration