Evidence -Based Approaches to Public Health: Concepts of Epidemiology Flashcards

1
Q

Ratio

A

Dividing one number by another, but the numerator does NOT need to be a subset of the denominator. 2 different quantities

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2
Q

Proportion

A

Dividing one number by another, but the numerator DOES need to be a subset of the denominator

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3
Q

Rate

A

Dividing one number by another but adding a time component in the denominator

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4
Q

Incidence

A

Measure of the number of new cases of a disease

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5
Q

Cumulative Incidence

A

Number of new cases of a disease in a period of time

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6
Q

Incidence Rate

A

Number of new cases of the disease during person-time of observation

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7
Q

Prevalence

A

Number of existing cases of a disease during a given time period. May include new cases as well

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8
Q

Point Prevalence

A

The proportion of the population that is diseased at a single point in time

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9
Q

Period Prevalence

A

The proportion of the population that is diseased during a specific duration of time

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10
Q

Endemic

A

A situation in a community in which there is a consistent elevated rate of a certain disease

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11
Q

Epidemic

A

An increase in the number of cases in a community, above what is expected

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12
Q

Pandemic

A

Worldwide epidemic

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13
Q

Descriptive Studies

A

Generally observational (no hypothesis testing)
- case reports
- case series
- cross-sectional

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14
Q

Analytical Studies

A

Interventional (experimental) and observational (hypothesis testing)
- Experimental
- RCT
- Non-Randomized Control Trial
- Observational
- Cohort
- Case-Control
- Cross-Sectional

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15
Q

Case Studies/Case Reports

A

Studies are used to alert people of a new illness or new association with illness. Reports of only people with the condition of interest.

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16
Q

Cross-Sectional Studies

A

Studies that include people who are representative of a given population. Not selected based on illness or exposure and can be used to determine initial association and identify the prevalence of either exposure or illness in a group.

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17
Q

Ecological Studies

A

Studies that are used to describe populations. Not analyzed on an individual level.

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18
Q

Ecological Fallacy

A

Group level data are used to report on individuals

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19
Q

Case-Control Studies

A

Studies select people with or without disease and then proceed to look back over time to see if people had different rates of exposure. Good for rare diseases with long latency periods

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20
Q

Latency Period

A

Diseases that take a long time to develop

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21
Q

Cohort Studies

A

Studies that selected people on the basis of exposure and determine if people develop the disease at different rates. Good for rare exposures and may follow individuals into prospective or retrospective. Incidence can be calculated from this type of study. Prevalence cases are excluded

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22
Q

Prospective

A

Into the future

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23
Q

Retrospective

A

Looking back in time

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24
Q

Prevalence Cases

A

People who have the disease at the time point when the study period begins

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25
Q

Randomized Control Trial (RCT)

A

Tests an intervention that is given by the researcher by 2 or more groups. People are randomly assigned into groups through randomization with one given the active item and the other group the usual treatment or a placebo. The researcher follows them over time and compares outcomes. Participants do not know which group they are in.

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26
Q

Systematic Review and Meta-Analyses

A

Pool the results of multiple independent studies with established criteria to identify the evidence for associations

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27
Q

Relative Risk

A

Measure of the magnitude of an association between an exposure and a disease that is used in cohort studies. Ratio of the risk (incidence) of disease exposed to the risk in the nonexposed

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28
Q

Odds Ratio

A

Calculated in case-control studies or cross-sectional studies. Odds of exposure among cases divided by odds of exposure among controls, which equals the odds of disease among the exposed divided by the odds of disease among the nonexposed.

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29
Q

RR or OR = 1

A

No association between exposure and outcome

30
Q

RR or OR > 1

A

Exposure increases the risk of the outcome

31
Q

RR or OR < 1

A

Exposure decreases the risk of the outcome

32
Q

Bias

A

A systematic error as compared to an error attributable to chance alone

33
Q

Selection Bias

A

Results from procedures used to select participants for a study. Occurs in a case-control or retrospective cohort study. This may also happen in a prospective cohort study and experimental studies

34
Q

Observation Bias

A

Arises from systematic differences in the way information on exposure or disease is obtained from the study groups

35
Q

Recall Bias

A

Inaccurate reporting of past events

36
Q

Interviewer Bias

A

Effects of the interviewer’s body language, voice, or demeanor on the response

37
Q

Misclassification Errror

A

Participants were classified into the wrong population.
- Differential (bias different between groups)
- Non differential (bias is equal across groups)

38
Q

Confounding

A

A third variable distorts the findings and is associated with both the exposure and outcome. Distorts the true association

39
Q

Effect Modification

A

The magnitude of the association between an exposure and outcome varies by the presence or level of a third variable. Clarifies the association

40
Q

Stratification

A

Divides the data according to the levels of the variable and allows the calculation of a measure of association for each strata

41
Q

Crude

42
Q

Koch’s Postulates

A
  1. Microorganisms must be found in abundance in all organisms suffering from the disease but should not be found in healthy organisms.
  2. It should be possible to isolate the causative microorganism from a diseased organism and grow it in pure culture.
  3. The organism from pure culture should be able to cause disease when inoculated into a healthy host organism.
  4. The microorganism should then be able to be isolated from the new host and grown in pure culture.

Helped identify causation

43
Q

Hills Nine Criteria of Causality (1965)

A
  1. Analogy
  2. Coherence
  3. Reversibility
  4. Specificity
  5. Plausibility
  6. Strength of the Association
  7. Consistency
  8. Biological Gradient
  9. Temporality
44
Q

Primordial Prevention

A

The earliest stage of prevention. Preventing risk factors of disease by targeting lifestyles, behaviors, and exposure patterns at the aggregate level instead of the individual level in order to decrease the risk of disease

45
Q

Primary Prevention

A

Concerned with preventing disease. Takes place before biological onset of disease

46
Q

Secondary Prevention

A

Prevention is addressed by most screening programs. Occurs in the preclinical phase after the disease is present but before symptoms appear.

47
Q

Tertiary Prevention

A

Focused on rehabilitation and support. The disease has occurred, and the goal is to improve the quality of life and reduce symptoms.

48
Q

Feasibility

A

How likely the target audience is to participate in a recommended program

49
Q

Reliability

A

Repeatability

50
Q

Validity

A

The ability of a test to accurately identify diseased and nondiseased individuals

51
Q

Sensitivity

A

The ability of a test to correctly identify the number of people WITH the disease

52
Q

True Positives

A

Individuals who have the disease and test positive for the disease

53
Q

False Negatives

A

Individuals who have the disease and test negative for the disease

54
Q

Specificity

A

The ability of a test to correctly identify the number of people WITHOUT the disease

55
Q

True Negatives

A

Individuals who do truly do not have the disease and test negative

56
Q

False Positives

A

Individuals who do truly do not have the disease and test positive

57
Q

Positive Predictive Value

A

Number of people who test positive who actually have the disease divided by the number of positive tests

58
Q

Negative Predictive Value

A

Number of people who test negative for disease and do not have the disease divided by the number of people who tested negative

59
Q

Gold Standard

A

A definite diagnosis that has been determined by biopsy, surgery, autopsy, or another method

60
Q

Cutoff Value too Low

A

Sensitivity is high and specificity is low

61
Q

Cutoff Value too High

A

Sensitivity is low and specificity is high

62
Q

Receiver Operating Characteristic Curve

A

Used to set the cutoff value of a continuous value test

63
Q

Lead Time Bias

A

Overestimation of survival duration attributable to earlier detection by screening than by clinical presentation

64
Q

Length Bias

A

Screening is more likely to detect cases that are progressing slowly compared with those with rapid progression of diseases, that manifest clinically. Overestimation of survival

65
Q

Statistical Signifance

A

Whether the calculated estimate is likely to be observed assuming the null hypothesis is true

66
Q

Practical/Clinical Significance

A

Subjective Assessment of whether the effect estimated in a test is “important” or “meaningful”. Not summarized in a specific measure. Based on researchers knowledge of the environment and judgement as to whether the estimated effect is meaningful

67
Q

Social Determinants of Health

A

Factors in a social environment that contribute to or detract from the health of individuals and communities. Ex. socioeconomic status, transportation, housing, access to services, discrimination by social grouping, and social or environmental stressors.

68
Q

Surveillance

A

Systematic ongoing collection, analysis, interpretation, and dissemination of health data. Ex. diseases, birth and death certificates, disease registries

69
Q

Active Surveillance

A

The research team goes out into the community and looks for cases of the disease. Accurate but expensive

70
Q

Passive Surveillance

A

Relies on existing reporting systems

71
Q

Digital Surveillance

A

Refers to web crawling to identify reports of disease.

72
Q

Sentinel Surveillance

A

Monitors a special community to look for changes in the distribution of disease. Conducted in a small location.