Term
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Definition
| the study of distribution, determinants and deterrents of morbidity or mortality in human populations |
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Term
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Definition
| a behavior, environmental exposure, or inherent human characteristic that is associated with an increase probability of an important health-related condition |
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Term
| what are 5 objectives of epidemiology? |
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Definition
1. identify cause of disease and risk factors
2. determine extent disease is found in community
3. natural history
4. evaluate existing and new preventitive/therapeutic measures
5. provide foundation for developing public policy |
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Term
| explain the disease iceberg concept |
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Definition
we can only see 4/5 the iceberg.
if we relied only on clinicians, they would overestimate severity of disease.
if we only measure number of patients with flu, we would underestimate since many rely on home treatment. |
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Term
| define distribution in the definition of epidemiology? |
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Definition
| referes primarily to how morbidity or mortality is distributed in popoulation. Person, place, and time |
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Term
| what are examples of person variables? |
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Definition
| age , sex, occupation, race, environmental exposures, health stauts, education.. |
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Term
| what are 3 types of temporal patterns of disease? |
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Definition
1. short-term fluctuation (spike of parasitic infection through water supply)
2. cyclic patterns (increase in traffic accidents during labor day)
3. secular trends (long-term changes in morbidity/mortality patterns). |
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Term
| what is a major focus of descriptive epidemiology? |
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Definition
| distribution of morbidity or mortality by person, place or time variables |
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Term
| what is a major focus of analytic epidemiology? and how is it usually accomplished? |
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Definition
| determinants, or to identify the causes of morbidity or mortality occur. Usually accomplished by testing hypotheses using variety of epi research designs. |
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Term
| what is a major focus of clinical epidemiology? |
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Definition
| deterrents. prevent, reduce, or control mortality. interventions. |
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Term
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Definition
1st true epidemiologist.
first to base his conclusions on observations.
used rational versus supernatural |
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Term
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Definition
| believed to be the first to articulate formally a theory of disease transmission by contagion |
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Term
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Definition
| Used "Bills of Mortality" quantified disease patterns in London and associated births and deaths with age, sex and other factors. |
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Term
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Definition
| Insisted observation should guide the study of the natural history of disease rather than merely theoretical explanations |
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Term
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Definition
| formed and tested hypothesis on the origins of cholera in London. One of the first analytic epidemiologic studies |
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Term
| what are the top 5 leading causes of death in 2010? and what was the number one in 1900? |
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Definition
1. pneumonia and influenza (1900s)
(2010) 1. CVD
2. Cancer, 3. Stroke, 4. Lower Respiratory Disease, 5. unintentional injuries |
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Term
Ch. 3:
Communicable diseases |
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Definition
| (infectious diseases) can spread through contact, inhalation, ingestion |
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Term
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Definition
| noninfectious diseases i.e. diabetes, skin cancer, stroke |
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Term
explain the ecological model in terms of host, agent, and environment:
when does disease result? |
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Definition
disease results when agent, environment, and host are no longer in balance.
host factors: immune status, general health, age, sexsx, genetics
agent: biological, chemical, and physical
environment: weather, living conditions, sanitation, population density |
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Term
| health field concept was developed by who? |
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Definition
| Marc Lalonde; early holistic model of health to serve as a basis for public health planning and policy making |
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Term
| Natural History of Disease: what are the 4 stages |
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Definition
| susceptibility, presymptomatic disease, clinical disease, diminished capacity |
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Term
| give an example of the stage of susceptibility |
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Definition
hypertension, diabetes -> increase risk of CVD
lack of sleep, stress, poor eating -> common cold |
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Term
| stage of presymptomatic disease |
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Definition
disease process has begun, no overt signs.
For communicable -> incubation period (time b/t invasion of disease and first symptoms)
For noncommunicable -> latency period (or induction period) i.e. cancer passes through three steps during this period (initiated, promoted, and progressed)
-subclinical disease: disease fully developed but no symptoms in the host (Typhoid Mary) |
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Term
| stage of clinical disease |
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Definition
| disease is apparent and host experiences 1+ signs or symptoms |
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Term
| stage of diminished capacity (2) |
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Definition
convalescent period: individual not yet returned to former level of health
residual disability: results from diseases that produce temporary or protracted complications
this stage generally concludes in either full recovery or death |
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Term
(3) types of prevention.
Primary prevention: |
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Definition
prevent disease before it develops so as to maintain health; promote general health and avoid risk factors. Health education
ex: vaccinations, diet, exercise, don't smoke |
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Term
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Definition
intended to reduce duration and severity; decrease prevalance of disease; early dectection and swift treatment of disease
ex: cancer screening, screening infectious disease markers |
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Term
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Definition
therapeutic and rehabilitative measures. intended to reduce complications & disability. connected w/ recovery, disability, or death.
ex: support groups, management via medication, diet, exercise |
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Term
| example of TB and prevention: |
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Definition
1st: (+) TB but don't show symptoms
2nd: chest x-ray (-)
so means you host disease but at the subclinical stage so can get treated |
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Term
| what is the difference between antibodies and antigens? |
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Definition
| antibodies help produce imuunity to disease; antigen is an invading substance that triggers production of antibodies |
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Term
| (3) types of immunity are? |
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Definition
active immunity (vaccines or lifetime serums)
passive immunity (maternal or therapeutic)
herd immunity (large % of pop immune) |
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Term
| is the study observational, or experimental? what is the difference |
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Definition
observational- the subjects naturally divide themselves. exposure status is NOT under control of the investigators.
experimental- involve some type of intervention and control of exposure status by the investigators. |
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Term
| what is the directionality of the study? |
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Definition
| cross-sectional, cohort, case-control |
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Term
| what is the timing of data collection? |
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Definition
| concurrent, historical, mixed |
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Term
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Definition
| a measure of intensity that occurs in events in a defined period of time |
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Term
| what is the difference in a person-time incidence rate and a cumulative incidence rate? |
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Definition
both rates describe new cases.
person-time uses person-time units and account for drop-outs, deaths, in study in the denominator.
cumulative incidence is a measure of risk of disease development. IR(cum) assumes that subjects enter study at the same time. |
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Term
| what is a prevalence rate and how does it differ from incidence rate? |
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Definition
prevalence deals with what exists, and incidence rates deal with new cases.
Prevalance rates reflect risk and duration. They do not estimate risk, like incidence. |
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Term
| what are confidence intervals used to estimate? |
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Definition
| the probable range in which the population rate lies. Sample size, sample variance, and chose confidence level affect the range of confidence intervals |
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Term
| what are crude rates? what are their cons? what is the solution to crude rates? |
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Definition
overall or summary rates for a defined population. can be distorted (confounded) by differences underlying population distriubutions, especially age
solution: adjusted rates |
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Term
| the direct method of age adjustment needs what to use? |
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Definition
| age-specific rates for the populations being compared must be available and stable |
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Term
| the indirect method of age-adjustment determines what? |
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Definition
| how the summary rate chaanges in the population with unavailble specific rates, after applying the specific rates of the standard population |
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Term
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Definition
| the strength of the association between an exposure and outcome |
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Term
| A difference indicates what of the outcome? |
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Definition
| how much of the outcome in the exposed group is associated with the exposure |
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Term
| spurious associations are what types of associations and what do they result from? |
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Definition
| false associations. usually result form sampling error or bias |
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Term
| noncausal associations are what types of associations and are a result of what? |
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Definition
| they are real associations, but are not causal associations. usually they represent secondary associations due to confounding factors. |
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Term
| Who developed Hill's postulates? And what are they? |
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Definition
| Sir Austin Bradford Hill. 1. correct temporal sequence. 2. strength of the association. 3. consistency of the association. 4. dose-response relationship. 5. biological plausiblity. 6. experimental evidence. |
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Term
| studies ranked from major types of epi studies in degree to which causal association is likely to be demonstrated: |
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Definition
1. RCT
2. Rcommunity trial
3. prospective cohort
4. retrospective cohort
5. case-control
6. cross-sectional
7. ecological
8. descriptive study |
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Term
| what is a necessary cause? |
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Definition
| one that is required to produce an outcome |
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Term
| what is a sufficient cause? |
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Definition
| one that can produce an outcome by itself |
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Term
| what is the most common types of causes that account fo rmost chronic diseases? |
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Definition
| not neccessary and not sufficient |
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Term
| what measure of association is used for case-control studies? |
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Definition
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Term
| what measure of association is used for cohort studies? |
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Definition
| OR or RR. Relative Risk is the most frequently used measure of association |
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Term
| when is the odds ratio a very good approximation of the relative risk? |
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Definition
| when the disease is infrequent |
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Term
RR is important as a measure of the strength of association and potential for a causal relationship. So, attributable risk looks at:
and it asks: |
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Definition
Looks at the amount or proportion of disease incidence (or disease risk) that can be attributed to a certain exposure.
It asks: how much of the disease occurred can be attributed to certain exposure?
Indicates: potentential for prevention if exposure eliminated |
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Term
| What are two causes of spurious associations? |
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Definition
they are false associations.
either sampling error, or bias. |
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Term
| what are two causes of noncausal associations? |
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Definition
| either confounding, or exposure order. |
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Term
| if a study is accurate, it is _____. |
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Definition
| Valid. Have you chosen to measure concept accurately? It is the extent to which the study findings are free of error. |
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Term
validity = _____
(2) types |
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Definition
the degree of systematic error.
1. internal validity - relates to target population
2. external - relates to other populations |
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Term
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Definition
| systematic error in selecting/retaining subjects (i.e. non-response of potential study subjects) |
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Term
| measurement bias (2) types |
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Definition
error in classifying subjects to exposure or outcome status (information bias)
(1) differential: over or underestimates magnitude of the measure of association. systematic (nonrandom) error
(2) nondifferential misclassification: results in dilution of the measure of association toward the null value |
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Term
| How do we control for bias? |
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Definition
| Random selection, standardizing measurement, blinding investigators, aggressive following of subject to remain in study |
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Term
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Definition
-must be associated with both exposure and outcome variables
-cannot be intermediate step (mediator)
(+) confounder overestimates
(-) confounder underestimates
-threatens internal validity |
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Term
precision =
and two types of common error are = |
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Definition
the degree of nonsystematic error.
two types: random measurement error and sampling error |
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Term
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Definition
random variation in sample. the study sample will never perfectly represent target population.
type I(alpha level): probability of finding association when NONE exists
type II(beta level): probability of NOT finding association when one does exist
type II is safer |
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