primary prevention
prevents an illness or injury from occurring at all by preventing exposure to risk factors
Example:
secondary prevention
seeks to minimize the severity of the illness/disease or the damage due to an injury-causing event once the event has occurred.
Example:
tertiary prevention
seeks to minimize disability by providing medical care and rehabilitation services
tragedy of the commons
a situation in which multiple individuals, acting independently in their own self-interest, will ultimately deplete a shared limited resource.
Example: air, water, environment we share
intervention study
closest to traditional lab experiment
experimental group receives exposure or intervention
control group does NOT receive exposure or intervention
Investigator assigns subjects to the treatment group or control group and watches over time and compares out
Top 10 Public Health Achievements
Vaccination, Motor Vehicle Safety, Workplace safety, Control of Infectious Disease, Decline in deaths from heart disease and stroke, safer and healthier foods, healthier mothers and babies, access to family planning and contraception, fluoridation of drin
epidemiology
the study of disease occurrence in human populations and factors that influence these patterns.
the diagnostic discipline of public health and the primary component of the assessment function.
Cholera Epidemic London
Snow formulated the hypothesis that cholera was spread by polluted drinking water. It was found that households who had their water supplied by Southwark and Vauxhall had much higher rates of cholera.
Why is epidemiologic surveillance important?
1) Detection at an early stage
2) Recognition of a new disease
3) Threats of bioterrorism
Steps in an Outbreak Investigation
1) Verify the diagnosis
2) Construct a working case definition
3) Find cases systematically - active surveillance
4) Ask "who, where, and when" to describe the epidemic by person, place, and time.
5) Consider the incubation period.
6) Look for common sour
chronic disease epidemiology
multiple and complex causes, develop over time, rather than rapidly fatal
goal: prevent or slow their onset and identify cause of progression... need to identify risk factors and observe long-term trends.
incidence
number of new cases in a defined population over a defined time period - most helpful in trying to link to the cause
prevalence
number of existing cases - most helpful for having an overall sense of societal impacts and planning for healthcare
WHO
characterizes people with the disease outcome by gender, age, occupation, race, etc.
WHEN
looks for trends in disease frequency over time
WHERE
looks at comparisons of disease frequency in different countries, states, counties, or other geographical areas.
descriptive epidemiology
analysis of disease causes provided from the who, why, and where questions. hypotheses are generated from this type of epidemiology and tested through formal studies. these studies are designed to confirm/disprove hypotheses derived from this type of epid
case-control study
people who have the disease are questioned about past exposures and compared with exposures of persons who do not have the disease.
control group consists of healthy individuals chosen to match the cases as much as possible. (similar in age, sex, and othe
cohort study
for situations when doing an intervention would be unethical or too difficult
considered the most accurate
choose a large number of healthy people, collect data on their exposures, and track outcomes over time
major differences from intervention is that p
random variation
results are due to chance and not a relationship between the variables of interest - if the group being studied is too small, a cause-and-effect relationship is likely to be missed or a false relationship may show up. common source of error in small epide
confounding variables
factors associated with an exposure that may independently affect the risk of developing the disease. common source of error in large cohort studies.
bias
systematic error in the design or conduct of a study that leads to a false association between exposure and disease
selection bias
an error due to systematic differences in characteristics between those who are selected for a study and those who are not. (hospital selection... people in hospitals are sicker...phone and internet surveys... access to internet not always viable for elde
recall bias
error that occurs when there is a differential level of accuracy in the information provided by compared groups
validity factors
1) Large study population
2) Strong association.. high relative risk
3) Dose-response relationship... x-ray exposure - the higher the dose of radiation, the greater effect on lifespan
4) known biological explanation
5) Consistent results from several stud
Tuskegee Syphilis Study (1932)
Purpose was to observe the course of the disease, but investigators did not explain the experiment to the men or seek permission/consent. In 1940s, penicillin was discovered to treat syphilis, but researchers WITHHELD the antibiotic from the Tuskegee subj
informed consent
subjects must freely consent to participate
definition of public health
mission: the fulfillment of society's interest in assuring the conditions in which people can be healthy
substance: organized community efforts aimed at the prevention of disease and the promotion of health
framework: activities undertaken within the form
Assessment
the diagnostic function, in which an agency collects, assembles, analyzes, and makes available information on the health of a population.
Policy development
the use of scientific knowledge to develop a strategic approach to improving the community's health.
Assurance
ensuring that the services needed for the protection of the community's health are available and accessible to everyone
responsibility of public health
educate the public and politicians about crucial role in maintaining and improving the health of the public
science of public health
how we understand threats to health, determine what interventions might work, and evaluate whether the interventions worked
politics of public health
how we as a society make decisions about what policies to implement
biomedical sciences
study of biological processes underlying human health and disease; prevention/control of diseases require an understanding of how infectious agents are spread or disease development process... also involves genetics, providing insights into people's inher
The Wakefield Study
Weak study design: no controls, only 12 in sample size, questionable recruitment, recall bias, conflicts of interest
Beating up the Data
although the subject matter is the same, the art is in how you present it
statistics
collection, analysis, interpretation, and presentation of numerical data; a collection of quantitative data; important to public health because it is concerned with populations, so it relies on ____ to provide and interpret data
uncertainty of science
results are not always certain, stats quantify a degree of uncertainty, contradictory results are common.
the public sometimes demands certainty where it does not exist
p-value
the probability of obtaining the observed result by chance alone
<0.05 = statistically significant
probability
what usually happens - however, as statisticians know, the improbable happens more often than people think
confidence interval
range of values within which the true result
narrower = lower likelihood of random error
wider = higher likelihood of random error
law of small probabilities
the most improbable things are bound to happen occasionally
(throwing heads on a coin flip 100 times in a row) (few people with fatal illness recover)
Power of a study
...