TEST 1 Flashcards
what is epidemiology
-disease states and events in objective, scientific and controlled manner
-screening, intervention, preventing bad health outcomes
-prevalence and incidence
-answers questions
prevalence
-portion of people who have the condition of interest in a population
-how is disease distributed in population (group with common characteristic)
-person, place, time
-point prevalence- # of cases at specific point in time
-period prevalence- # of cases over defined period
-lifetime prevalence- proportion of people who have had disorder at any time during life
incidence rate
-the rapidity with which newly dx cases of disease develop
2 principles epidemiology is based on
-1. disease doesnt occur at random -> things that increase and decrease likelihood
-2. these factors can be identified by systematic investigation of population
sample, sample error
-subgroup within a population
-sample error- natural variability in a population
-ex. measuring bus capacity on a middle school bus -> everyone weighs slightly different
selection bias
-sample is not random -> sample is chosen with subconscious bias
-ex. testing sugar on diabetics but all the diabetics are members from your church
-ex. more female pts in groups bc they reminded the researcher of his mother
validity vs reliability
-validity- accuracy
-reliability- repeatability of test
nominal vs ordinal vs interval data
-nominal- data that has no order -> name
-ex. blood type, eye color
-ordinal data- has a particular order
-ex. pain scale 1-5
-interval data- clear order data point -> mean, mode, median -> precise measurements
sub-disciplines of epidemiology
-disease- cancer, cvd, infectious
-exposure- environmental, genetic, nutritional
-population- clinical, geriatric, pregnant
sequence of epidemiologic investigation
-1. suspect exposure influences a disease (DESCRIPTIVE)
-2. hypothesis (DESCRIPTIVE)
-3. investigation to measure relationship (ANALYTIC/SCIENTIFIC)
-4. judge if relationship is significant -> chance, bias, confounding variables (ANALYTIC/SCIENTIFIC)
-5. evaluate preventions and tx (ANALYTIC/SCIENTIFIC)
confounding variable
-a variable that could also be causing a disease process in addition to the independent variable
-lead to paradoxical results
-ex. giving a drug to deadly cancer pts -> the drug looks like its working poorly but the pts were just really sick
-ex. coffee drinkers have a higher likelihood of CVD -> but coffee drinkers also have a higher likelihood of smoking
-not clear which is causing the result
hypothesis
-1. project the expected assoc between two or more measurable variables
-2. state clear implications for testing stated relations
-advance research
-guide study, variables, sample, analysis, interpretation
-fundamental hypothesis -> operational hypothesis
-ex.Caregivers to relatives with dementia will have a higher incidence of high blood pressure than non-caregivers, mediated through higher levels of stress-related symptoms
2 types of epidemiology
-descriptive -> monitor public health and hypothesizes about causes of disease -> identify and count cases of disease and conduct studies
-case report, case series, cross-sectional study
-ex. is this an outbreak?
-ex. framingham
-surveys- qualitative
-DESCRIBE PATTERNS
-analytic/scientific -> eval hypothesis about causes of disease and eval success of intervention -> compare groups and determine association
-clinical trial, experimental, case-control, cohort
-SEARCH FOR CAUSES AND PREVENTION
framingham study
-5,000
-MA
-1947
-50 years
-every 2 years fu
-nicotine, alcohol, conditions, dietary intake, emotional stress
-3rd generations
sources of data
-WHO- government, NGOs, HMOs, hospitals, researchers
-WHAT- US census, surveys, death certificates, birth certificates, cancer registries, discharge reports, etc.
-STRENGTHS- already exists, established methodology, little or no cost
-WEAKNESS- can be inaccurate, not the data you want, report delays, complicated methodology
descriptive data sources: specific
-census of US population- every 10 years, demographics
-vital statistics- birth, death*, marriage, divorce, fetal death
-national survey of family growth- marriage, divorce, family planning, infertility
-national health interview survey- major health problems
-national health and nutrition exam survey- diet and health
-behavioral risk factor surveillance system- telephone
-national health care surveys- use and quality of health care
-notifiable disease surveillance system- weekly data on diseases like STDs
-national immunization survey
-national survey of drug use and health- mental health and drugs
-surveillance, epidemiology, and end results program- prevention, dx, and tx of cancer
-birth defect surveillance and research programs
pure research
-abstract and general
-generating a new theory
-goal- gain new knowledge
-theory!
clinical research
-in a clinical setting
-cant control variables
-ex. drug trials
-experimental research can control variables
-laboratory- done in a lab where surroundings are controlled
applied research
-answers practical questions to help people do their jobs better
-ex. time use studies, eval of diff types of interventions with the same purpose
-ex. using a mouse vs using a track pad improves work speed
4 components for measuring disease frequency
-1. population (which group)
-2. cases of disease (numerator)
-3. size of population (denominator)
-4. time (be explicit)
population
-can be defined by area or characteristic
-FIXED- permanent -> Ex. veteran of vietnam, people born in 1982
-DYNAMIC- state or condition -> ex. residents of boston, parents of teenagers
measuring disease frequency
-ratio- numbers dont need to be related
-prevalence- proportion- numbers are related, %
-people with disease/TOTAL population
-point prevalence- # with disease on a single day
-rate- time is the denominator (incidence rate)
-NEW CASES
-involves a transition- (nonsick -> sick, al mive -> dead)
-denominator - population AT RISK
-dont include immune pts, pts who already have the disease, males (if studying uterine cancer)
prevalence vs incidence
-prevalence- existing disease
-assess burden of disease
-allocate resources
-administration and planning
-conditions with uncertain onset (MS, depression)
-incidence- new disease
-what is causing this disease
-eval preventions
-eval tx
-cumulative incidence- time is described in words
-incidence rate- time is part of denominator
cumulative incidence
-new cases during a specified time period
-transition (not sick -> sick)
-denominator- population at risk
-critical assumption- all people have been followed for entire time period
-risk of developing disease over time period
-# new cases/# in population AT RISK at start of time period
-relevant time period does not appear in equation but is stated in WORDS
crude mortality rate, cause specific mortality rate, age specific mortality rate
-Crude mortality rate: Total # of deaths from ALL causes per 100K per year
-ex. 2015- 844/100,000 in US
-Cause specific mortality rate: Total # of deaths from a SPECIFIC cause (AIDS) per 100K per year
-ex. 2015- 197/100,000 in US
-Age specific mortality rate: Total # of deaths from ALL causes among individuals in a specific AGE category (< age 1) per 100K per year
-ex. 2015- 590/100,000 in US
risk
new cases/persons at risk
incidence rate
-number of NEW cases of disease / PT
-PT- total disease-free observation within the source population
population comparisons
-assignment- measure INCIDENCE RATE of study population and control group
-assessment- determine prevalence in study group
and control group
-results- compare prevalence of variable with the incidence rates of disease in study group and control group
-interpretation- draw conclusions
-extrapolation- draw conclusions about people that arnt in your studied population
-group association
case control study
-comparing people with a disease (cases) with people without a disease (control)
-ex. women with stroke (case group) compared to women without stroke (control) -> determine who takes BC and who doesnt
-individual association
randomized controlled trial
-groups are randomly assigned (case and control) and the case group is given a variable
-ex. women are randomly assigned a group -> case group gets BC and control does not -> determine who has a stroke and who does not
-altering the cause alters the effect
cohort studies
-cause precedes effect
-following a population over time
-ex. framingham study
