Epidemiology

1. Definition of epidemiology 2. Meaning of the distribution, determinants, and disease frequency in the definition 3. What person, place, and time factors mean in practice 4. Examples of person, place, and time factors that epidemiologists study 5. Historical events and people who shaped the field of epidemiology

what is epidemiology

the study of the distribution and determinants of disease, risk factors and exposures, and health status in populations 

distribution

person, place, and time

determinants

factors that influence whether a person develops a disease or health condition

Person factors

age sex and socioeconomic status and family history affect disease

John Graunt

summarized the pattern of mortality using statistics

James Lind

discovered the cause of scurvy in the 18^th century (oranges) 

Edward Jenner

developed a smallpox vaccine in the 18^th century 

William Farr

improved john graunts work developed a disease registration system in the 19^th century

John snow

cholera + water

Robert Koch

(germ theory) development of 4 postulates: microorganism must be observed in every case of the disease, must be isolated and grown in pure culture

florence nightingale

founder of modern nursing + used statistics to help improve hospital settings

Epidemiologic Transition

a shift over time where infectious diseases decrease and long term chronic diseases become the main health problem-more deaths from infectious diseases, poor sanitation, malnutrition.

Biological gradient

more exposure=more risk

Biological Plausibility

does the proposed relationship make biological sense

Consistency

does the same association appear in multiple studies/populations/settings

specificity

one exposure leads to one specific disease/outcome

Disease Etiology

searching for causes of disease 

primary prevention

preventing disease before it occurs. ex: seatbelts, vaccines 

secondary prevention

detecting disease in an early stage, cancer screening programs that identify cancer in early stages when it is treatable. ex: Blood pressure screening to detect and treat hypertension 

Tertiary

reduces the effects of a disease after it happens

fixed population

a group whose membership is permanent and defined by a specific life event

dynamic population

a group whose membership changes constantly over time

characteristics of a population

group of people sharing common traits, ex: place risk factors

Descriptive Epi

describes what is happening in the population, relies on person, place, and time (demographic, community infrastructure, health outcomes, environmental variables)

Community Infrastructure

resources and structures that exist within a community. Social and health service availability, Quality and housing, Social stability 

demographic and social variables

describe the characteristics of the population. age, sex, race, ethnicity, income, education, employment

Health related outcomes 

health conditions being studied within a population. Infant Mortality, Teen pregnancy, Sti, Substance abuse, Homicide + suicide rates, Chronic and infectious disease prevalence.

Environmental Variables

characteristics of the physical environment. Air pollution, Access to green space, Access to clean water, Access to healthy food, including schools, Number of liquor stores and fast food, Radon levels (indoor pollutant) 

Incidence

new cases coming in, involves a period, new cases 

Prevalence

measures presence of existing cases of disease in a population during a specific moment in time

prevalence=

existing cases/population*100

mortality=

deaths/population*1000

Cumulative incidence rate=

new cases/population at risk in the beginning

risk factor/cause

a factor that contributes to producing the disease

disease frequency

how much disease is occurring in a population (prevalence, incidence, mortality)

how is epidemiology used in practice

who what when where why, cause, plan interventions