Epi Classes 1 & 2 Flashcards
“The Epidemiologic Transition”
The disease of concern to populations are constantly shifting.
A population shift in disease and mortality patterns in high income countries:
- before transition (low income countries): most deaths from infection and malnutrition; high infant mortality rates; short life expectancy.
-after transition (high income countries): most deaths from heart disease, cancers and stroke; low infant mortality rates; long life expectancy
20th century epi
Refinement of epidemiological methods: outbreak investigation, study design for chronic diseases, clinical trials, biostatisical analysis
Cigarette smoke found unhealthy (1951-1963)
Eradication of smallpox (1978)
Increased focus on chronic disease and not just infectious disease/life expectancy
Analytic Epidemiology
“Agent” “Host” “Environment”
Why?/How?
Looks for causes/test hypotheses
Arthropod vectors
Bugs like mesquitos that carry disease. Discovered in 19th century as a carriers for diseases such as malaria, yellow fever, sleeping sickness and typhus
Asymptomatic Carrier
Person that carries and spreads disease but shows no symptoms. Discovered in 19th century as a contributor to disease spread.ex. typhoid mary
Bernardo Ramzzini
1633-1714: published comprehensive “disease of workers” detailing environmental hazards for 52 occupations.
Bias
An over or underestimation of something (value, factor)A miscalulation by the system
Case Fatality Rate (CFR)
deaths from a specific cause/# with the specific disease
The proportion of reported cases of a specified disease or condition which are fatal within a specific time.
CFR is a measure of the severity of a disease
Cohort
A group of people that can be followed over time
Criteria for a Risk Factor
- The frequency of disease varies by category or value of the exposure
- The risk factor (exposure) precedes the onset of the disease
- The observed association is not due to any source of error
- Association does not equal Causation
Descriptive Epidemiology
“Person” “Place” “Time”
Who? Where? When?
Disablity-Adjusted Life Year (DALY)
Measure of overall disease burden, expressed as the number of years lost due to ill-health, disablity or early death
Edward Jenner
1798: developed smallpox inoculation. Took cowpox and injected it into an 8 year old. After multiple injections over time, he was unable to catch smallpox
Efficacy
The abliity of an intervention to achieve the desired results under ideal conditions
Endemic
A disease or condition normally found in a population.
An infection is said to be endemic in a population when it is maintained without the need for external input
Epidemic
Higher than normal (baseline) incidence rates in a population.
A widespread occurance of an infectious disease in a community at a particular time
Health
A state of complete physical, mental and social well-being and not merely an abscense of disease or infirmity
Health Research
Examines the biological, socio-economic and environmental factors that contribute to health, disease, illness, diability and death
Henle-Koch Postulates
- The agent must be present in every case
- One agent = one disease
- Exposure of healthy subjects to suspected agents results in disease
History of Epi: Hippocrates
1st to recognize environment’s role in disease etiology. He listed environmental, dietary, behavior and constitutional conditions.
Recognized early epidemicsWrote thorough descriptions of clinical diseases like tetanus, typhus, and tuberculosis
History of Epi: The demographic approach: Use of vital statistics
14th and 15th century: Italy began tracking death rates and causes (especially from bubonic plague).
1592: England begins to issue death certificates
Incidence
The occuraence, rate, or frequency of a disease, crime or somethign else undesireable
Jakob Henle
1809-1885. Helped create germ theory. Proposed in 1840 that sick people pass contagious substances to healthy individuals
James Lind
1747: studied etiology and treatment of scurvy by assigning random treatment to sailors
John Graunt
1620-1674: “founder of vital statistics”. 1st use of populaiton mortality data to study disease occurance