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26 Cards in this Set
- Front
- Back
Exposure pathway
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The physical course a pollutant takes from the source to a subject.
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Exposure Route
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Way a substance enters the body
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Exposure assessment
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The study of distribution of determinants of substances or factors affecting human health:
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3 components of exposure assessment
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1)design of the study
2)data collection 3)interpretation of the data |
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Dose
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is referred to the exposure after uptake of the body.
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Exposure
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A substance or factor affecting human health (adversely or beneficially). In Occupational or Environmental Epidemiology- generally contact with a substance through and environmental medium and surface of the human body.
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Source-receptor models
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Include the routes and pathways of exposure and a helpful in understanding how people are exposed.
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3 possible exposure routes for humans
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1. inhalation through respiratory system
2. ingestion through gastrointestinal system 3. absorption through the skin. |
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3 dimensions of exposure
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1. Duration (ie, hours or days)
2. Concentration 3. Frequency (ie, times per week) [can be used as an exposure index in an epidemiological stdy. i.e., exposures that cause acute effects, the short term concentration is generally the most relevant exposure index.] NOTE: these can be combined such as duration x concentration = cumulative exposure. |
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Within and between subject exposure variability
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Exposure generally varies from day to day for any subject and from subject to subject.
Can be estimated with repeated exposure measurements |
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2 main approaches to obtaining exposure estimate(s) for a population
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1. Individual (ie every member of a population is monitored either once or repeatedly.
2. Exposure grouping population is split into smaller subpopulations or "exposure groups" based on determinants of exposure & group or ecological estimates are obtained for each exposure group. |
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Pros & Cons of expert and self-assessment methods
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Pro: easiest and cheapest, generally.
Con: Can suffer due to lack of objectivity and knowledge, and may introduce bias. |
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More objective way to assess exposure
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- Measurement.
ex: Levels of outdoor pollution assessed by ambient air monitors. ex: Levels of substance into body can be estimated by biomonitoring. |
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Deterministic Modeling
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One of two types of modeling - in which the models describe the relationship between variables mathematically on the basis of knowledge of the physical, chemical, and or biological mechanisms governing these relationships.
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Stochastic Modeling
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One of two types of modeling - statistical relationships are modeled between variables.
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Accuracy
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The degree to which a measurement or an estimate represents the true value of what is being measured
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Bias
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Deviation of results or inferences from the truth, or processes leading to such deviation; any trend in the design, collection, analysis, interpretation, publication or review of data that can lead to conclusions that are systematically different from the truth.
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Limit of Detection (LOD)
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The minimum concentration of an analyte, in a given matrix and with a specific method, that statistically is significantly greater than zero, that is, the lowest concentration that can be measured with a certain degree of confidence
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Precision
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The degree of variability in a measurement or estimate, estimated, for example, by the standard error of measurements or the standard deviation in a series of replicate measures
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Power
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The ability of a study to demonstrate statistically significant effects, which is determined by a number of factors including study design, magnitude of effect, and sample size.
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Reliability
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The degree of stability exhibited when a mesurement is repeated under identical conditions - the degree to which the results obtaind by measurement procedure can be replicated.
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Reproductibility
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A test or measurement is repeatable if the results are identical or closely similar each time it is conducted
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Robustness
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A procedure is said to be robust if it is not very sensitive to departures from assumptions or variations in the conditions or practices under which it was set up
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Sensitivity
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Index of the performance of a diagnostic tool, for ex, for questionnaires: the proportion of truly exposed people in the population who are identified as exposed by the questionnaire.
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Specificity
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Index of the performance of a diagnostic tool, for ex, for questionnaires: teh proportion of truly non-exposed people in the population who are identified as non-exposed by the questionnaire.
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Validity
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An expression of the degree to which a measurement measures what it purports to measure.
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