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Flashcards in Module 2 Deck (13)
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1

Registries: Definition: Registries are organizations where information will be ___ on a particular ___ - for example, cancer - and will be ___ and ___ for medical and analytical ___as well as for ___ __.

Registries: Definition: Registries are organizations where information will be collected on a particular disease - for example, cancer - and will be stored and available for medical and analytical research as well as for disease reporting.

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Hospital-based cancer registries: The information collected is from a particular ___ with the purpose of___ __ __, quality and clinical evaluations. Although the information collected on hospital based registries are important for___ and to inform doctors and the hospital staff it has ___ applications for epidemiological research.

Hospital-based cancer registries: The information collected is from a particular hospital with the purpose of improved patient care, quality and clinical evaluations. Although the information collected on hospital based registries are important for administrators and to inform doctors and the hospital staff it has limited applications for epidemiological research.

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. Reasons why a hospital-based cancer registry has limited epidemiological research applications are:

• Only includes the population served by the ___ __
• Does not include___ ___where the disease occur

• Cannot provide estimates of the disease effect in the ___ ___

• Results are usually not ___ to the entire population.

. Reasons why a hospital-based cancer registry has limited epidemiological research applications are: • Only includes the population served by the specific hospital • Does not include all cases where the disease occur • Cannot provide estimates of the disease effect in the general population • Results are usually not generalized to the entire population.

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Population-based cancer registries: Information is collected on __ ___ cases present in a specified ____. Below is the map of the populations included in the ___ ___ and ___ ___ (SEER) database.

Population-based cancer registries: Information is collected on all disease cases present in a specified population. Below is the map of the populations included in the Surveillance, Epidemiology and End Results (SEER) database.

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The objectives of cancer-based registries are:

• __ __and make available data on all new cases of disease present in the included population within a defined geographical area.

• Data is available for use in e_____ and __ ___research.

• Data collected is helpful on the ___  and assessment of disease the ____s of cancer control activities.

The objectives of cancer-based registries are: • Collect, store and make available data on all new cases of disease present in the included population within a defined geographical area. • Data is available for use in epidemiology and public health research. • Data collected is helpful on the monitoring and assessment of disease the effectiveness of cancer control activities.

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Cross-Section study design will:

• Examine the relationship between___ and ___ at the same point in time in a defined____. • It will assess the ___ of ____s and/or ____ s in the defined population.

Cross-Section study design will: • Examine the relationship between exposure and disease at the same point in time in a defined population. • It will assess the prevalence of exposures and/or of diseases in the defined population.

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It is very important to remember that:

• Th____ relationship between exposure and disease cannot be determined because the relationship between exposure and disease is examined at the___ ___ ___

. • ___ and not___ of disease is measured

National survey studies, Population-based survey studies are examples of cross-sectional studies.

It is very important to remember that: • The temporal relationship between exposure and disease cannot be determined because the relationship between exposure and disease is examined at the same time point. • Prevalence and not incidence of disease is measured National survey studies, Population-based survey studies are examples of cross-sectional studies.

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Strengths

• Relatively ___ ___ to conduct as exposure and disease are measured at the same time eliminating the need for follow-up

. • ___ ___ and ___ can be studied.

• Relevant for __ ___ as it collects the prevalence of disease and can estimate the burden of disease in a specified population

• Results from a cross-sectional study are important in __ ___ and ___ of resources.

• Excellent for __ __

Strengths • Relatively straight-forward to conduct as exposure and disease are measured at the same time eliminating the need for follow-up. • Multiple outcomes and exposures can be studied. • Relevant for public health as it collects the prevalence of disease and can estimate the burden of disease in a specified population • Results from a cross-sectional study are important in health policy and allocation of resources. • Excellent for generating hypotheses.

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Weaknesses

• Cannot measure___

• Cannot measure ___. Difficult to determine whether the outcome followed exposure in time or exposure resulted from the outcome.

• Not suitable for studying ___ diseases or diseases with a__ ___

• Limited ___ of identified associations

Weaknesses • Cannot measure temporality. • Cannot measure incidence. Difficult to determine whether the outcome followed exposure in time or exposure resulted from the outcome. • Not suitable for studying rare diseases or diseases with a short duration. • Limited interpretation of identified associations

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• Selection Bias: This bias occurs when you are constructing the sampling for your study. Remember that with cross-sectional studies you are including (sampling) ___ and not ___cases. Therefore for the person to be included in your study it is required that: o The __ ___ o The diseased person__ __ __ to be sampled in your study

• Selection Bias: This bias occurs when you are constructing the sampling for your study. Remember that with cross-sectional studies you are including (sampling) prevalent and not incident cases. Therefore for the person to be included in your study it is required that: o The disease occurred o The diseased person survived long enough to be sampled in your study

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• Examples: o You are not following a person for a period of time and observing if the person develops or not cancer. o You will also miss in cases the __ __ before being enrolled in a study or survey.

• Examples: o You are not following a person for a period of time and observing if the person develops or not cancer. o You will also miss in cases the person died before being enrolled in a study or survey.

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• Incidence-Prevalence Bias is a form of ___ bias: because cross sectional studies estimate ___ as a function of___, the __ __ __(PRR) will be biased.

o For example, cases with severe emphysema and more likely to smoke, will most likely die earlier than cases with less severe emphysema, so the prevalence of emphysema in smokers will be ____ compared to incidence.

• Incidence-Prevalence Bias is a form of selection bias: because cross sectional studies estimate Prevalence as a function of incidence, the Prevalence Rate Ratio (PRR) will be biased. o For example, cases with severe emphysema and more likely to smoke, will most likely die earlier than cases with less severe emphysema, so the prevalence of emphysema in smokers will be underestimated compared to incidence.

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Finally, the formal definition of BIAS: Bias may be defined as any __ __ in an epidemiological study that results in an __ __e of the true effect of an ___on the ___ of interest.

• Bias results from systematic errors, __ ___, in the research methodology.

• The effect of bias will underestimate or overestimate the true value of the study results, depending on the type of systematic error introduced. • Once bias is introduced, there are limited analytical options for the ___/___ of most forms of bias. Consequently, careful ___ and study ___ should be taken into consideration to minimize threats to study validity

Finally, the formal definition of BIAS: Bias may be defined as any systematic error in an epidemiological study that results in an incorrect estimate of the true effect of an exposure on the outcome of interest. • Bias results from systematic errors, non-random, in the research methodology. • The effect of bias will underestimate or overestimate the true value of the study results, depending on the type of systematic error introduced. • Once bias is introduced, there are limited analytical options for the adjustment/correction of most forms of bias. Consequently, careful sampling and study design should be taken into consideration to minimize threats to study validity