Podcast
Questions and Answers
What is the primary goal of epidemiology?
What is the primary goal of epidemiology?
Which of the following methods is NOT typically used in epidemiological studies?
Which of the following methods is NOT typically used in epidemiological studies?
What factor must be considered when determining whether an observed association is causal?
What factor must be considered when determining whether an observed association is causal?
What is prevalence, as used in epidemiology?
What is prevalence, as used in epidemiology?
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Who is recognized as the first psychiatric epidemiologist and studied suicide correlating with social control?
Who is recognized as the first psychiatric epidemiologist and studied suicide correlating with social control?
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What is the relationship between sample size and confidence intervals?
What is the relationship between sample size and confidence intervals?
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Which type of error occurs when a significant result is mistakenly found due to chance?
Which type of error occurs when a significant result is mistakenly found due to chance?
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What best describes bias in the context of a study?
What best describes bias in the context of a study?
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Which of the following is an example of measurement bias?
Which of the following is an example of measurement bias?
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Which approach is best for addressing confounding in a study?
Which approach is best for addressing confounding in a study?
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What is reverse causality?
What is reverse causality?
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What is an advantage of case-control studies?
What is an advantage of case-control studies?
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Which study type is least useful for determining causal relationships?
Which study type is least useful for determining causal relationships?
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Which of the following is NOT a Bradford-Hill consideration for causal inference?
Which of the following is NOT a Bradford-Hill consideration for causal inference?
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What is an essential feature of randomized controlled trials?
What is an essential feature of randomized controlled trials?
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How does selection bias typically arise in studies?
How does selection bias typically arise in studies?
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After adjustment for confounders, what term describes confounding that remains?
After adjustment for confounders, what term describes confounding that remains?
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Which type of study primarily assesses disease frequency at a single point in time?
Which type of study primarily assesses disease frequency at a single point in time?
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In ecological studies, what is typically compared?
In ecological studies, what is typically compared?
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What is the role of epidemiology in health services planning?
What is the role of epidemiology in health services planning?
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Which historical figure is known for his contributions to psychiatric epidemiology by studying social control and suicide rates?
Which historical figure is known for his contributions to psychiatric epidemiology by studying social control and suicide rates?
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When determining causation, which factor relates to systematic errors in study data collection?
When determining causation, which factor relates to systematic errors in study data collection?
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In the context of epidemiological research, what does incidence measure?
In the context of epidemiological research, what does incidence measure?
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Which of the following study designs is primarily used to assess the relationship between a risk factor and a health outcome over time?
Which of the following study designs is primarily used to assess the relationship between a risk factor and a health outcome over time?
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What happens to the width of the confidence interval (CI) as the sample size increases?
What happens to the width of the confidence interval (CI) as the sample size increases?
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Which of the following best describes systematic error in a study?
Which of the following best describes systematic error in a study?
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What is a key feature of randomisation in studies?
What is a key feature of randomisation in studies?
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How can reverse causality affect the interpretation of results?
How can reverse causality affect the interpretation of results?
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What is meant by residual confounding in a study?
What is meant by residual confounding in a study?
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How does selection bias typically influence study results?
How does selection bias typically influence study results?
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What is a major limitation of ecological studies?
What is a major limitation of ecological studies?
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Which Bradford-Hill consideration relates to the strength of the observed association?
Which Bradford-Hill consideration relates to the strength of the observed association?
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What describes a cohort study?
What describes a cohort study?
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In dealing with confounding, what is a common method applied during the design phase?
In dealing with confounding, what is a common method applied during the design phase?
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What is one way to minimize chances of selection bias in research?
What is one way to minimize chances of selection bias in research?
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What does the term 'multivariate methods' refer to in the context of confounding?
What does the term 'multivariate methods' refer to in the context of confounding?
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What does the term 'temporality' imply in causal inference?
What does the term 'temporality' imply in causal inference?
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What does a Type 2 error indicate in hypothesis testing?
What does a Type 2 error indicate in hypothesis testing?
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What is one of the primary reasons for conducting epidemiological research?
What is one of the primary reasons for conducting epidemiological research?
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Which historical figure is often regarded as the father of psychiatric epidemiology?
Which historical figure is often regarded as the father of psychiatric epidemiology?
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When assessing whether an association is causal, which factor does NOT play a significant role?
When assessing whether an association is causal, which factor does NOT play a significant role?
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Which measure represents the proportion of a population that has a specific condition at a certain point in time?
Which measure represents the proportion of a population that has a specific condition at a certain point in time?
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What is a potential drawback of relying solely on case reports in epidemiological studies?
What is a potential drawback of relying solely on case reports in epidemiological studies?
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What does a larger sample size do to the width of the confidence interval (CI)?
What does a larger sample size do to the width of the confidence interval (CI)?
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Which of the following best describes selection bias?
Which of the following best describes selection bias?
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What is the primary aim of randomisation in a study?
What is the primary aim of randomisation in a study?
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What does confounding represent in the context of a study?
What does confounding represent in the context of a study?
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Which statement accurately describes residual confounding?
Which statement accurately describes residual confounding?
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Which Bradford-Hill consideration emphasizes the need for consistent findings across various studies?
Which Bradford-Hill consideration emphasizes the need for consistent findings across various studies?
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What implication does reverse causality have in study results?
What implication does reverse causality have in study results?
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How is measurement bias typically introduced in a study?
How is measurement bias typically introduced in a study?
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What role do case-control studies primarily serve in epidemiological research?
What role do case-control studies primarily serve in epidemiological research?
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Which method is considered the best approach for reducing confounding in studies?
Which method is considered the best approach for reducing confounding in studies?
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What does the term 'dose-response' refer to in causal inference?
What does the term 'dose-response' refer to in causal inference?
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Why are ecological studies often limited?
Why are ecological studies often limited?
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What is a significant advantage of randomized controlled trials (RCTs) over other study designs?
What is a significant advantage of randomized controlled trials (RCTs) over other study designs?
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How does temporary exposure relate to causality in research?
How does temporary exposure relate to causality in research?
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Study Notes
Epidemiology Basics
- Epidemiology studies the distribution and determinants of disease frequency in human populations. This involves examining how often diseases occur and the factors that influence their occurrence within groups of people.
- Prevalence is the proportion of a population with a disease at a specific point in time. Example: in a population of 20 people, 4 have depression; Prevalence = 4/20 = 20%.
- Incidence is the rate of new cases of a disease in a population during a specific period; in a group of 16 people at risk, 2 develop depression; Incidence = 2/16 = 12.5%.
- Key aims of epidemiological research include planning healthcare, pinpointing disease causes and preventions, identifying high-risk groups, improving overall health, and reducing suffering.
- Psychiatric epidemiology focuses specifically on mental health outcomes in populations.
History of Epidemiology
- Hippocrates is considered the father of modern medicine.
- John Snow investigated cholera, challenging the miasma theory.
- Emile Durkheim was a pioneer in psychiatric epidemiology, studying suicide rates, noting differences in suicide rates between Catholics and Protestants, potentially linked to differing social controls.
Suspected Causes of Illness
- Methods used to investigate suspected causes include: lab studies, disease surveillance, case reports, theoretical reasoning, and clinical observation (determining outcome and exposure).
Making Inferences from Association
- Association does not equal causation.
- To determine if a relationship is causal, consider:
- Chance (statistical significance): Random variation in results, not necessarily a causal link; we need to understand the uncertainty involved and use statistics.
- Bias (selection bias, measurement bias): Systematic errors introduced during a study's design or conduction; the results are not a true picture of the target population.
- Confounding: An alternative reason for an observed link between exposure and outcome; other factors may be influencing the apparent link.
- Reverse causality: Whether the outcome is actually causing the exposure.
Chance in Epidemiology
- Random error is inherent in studies.
- P-values and confidence intervals (CIs) quantify uncertainty, helping to make inferences about the broader population.
- Larger samples provide more precise CIs (narrower width) and smaller p-values, reducing the likelihood of chance occurrences. A 95% CI is derived from the difference between groups and the standard error. A smaller standard error (achieved with larger sample sizes) indicates a more precise estimate, leading to a narrower confidence interval and a smaller p-value.
Bias
- Bias is systematic error, distorting inferences.
- Selection bias arises from differences between the study sample and the target population (e.g., low response rates, drop-out). Case-control studies are susceptible to this bias.
- Measurement bias (or information bias) arises from inaccurate/inconsistent measurement of exposures or outcomes. This includes observer bias (observer expectations) and recall bias (illness impacting memory).
Confounding
- Confounding is an alternative explanation for an observed association, potentially creating spurious associations or masking true ones.
- Confounders are third variables linked to both the exposure and outcome.
Dealing with Confounding
- Randomization is the ideal approach.
- Adjusting for confounders in statistical analyses. Multivariate techniques used in analyses will change observed associations.
- Residual confounding represents unknown, unaccounted-for confounders.
Reverse Causality
- Reverse causality suggests the outcome might be causing the exposure.
- Longitudinal studies are useful, measuring exposure before the outcome and following individuals over time.
Causal Inference (Bradford Hill)
- Temporality: Exposure must precede the outcome.
- Strength: Stronger associations suggest a higher likelihood of causality.
- Dose-response: Increased exposure is linked to increased risk.
- Consistency: Similar results in various studies across different populations.
- Specificity: A single exposure is associated with a specific outcome.
- Coherence: Alignment with existing scientific knowledge.
- Plausibility: Biological or other logical reasons exist.
- Analogy: Similar situations likely have similar outcomes.
- Experimental evidence: Supported by animal or experimental research.
Study Designs
- Cross-sectional studies: Examine characteristics and prevalence in a population at a specific time. These are often survey-based, and focus on prevalence and disease distribution (age, sex, social factors).
- Ecological studies: Compare disease frequencies between groups over time within a population, using existing data, aiming to expose correlations and patterns.
- Case-control studies: Identify cases and controls to assess associations with exposures.
- Cohort studies: Follow a population over time to measure risk factors and disease development.
- Randomized controlled trials: Participants are randomly assigned to different exposure groups to evaluate cause-and-effect relationships.
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Description
Explore the fundamental concepts of epidemiology, including prevalence, incidence, and its significance in health services. Learn about key historical figures like Hippocrates and John Snow, and the evolution of psychiatric epidemiology. This quiz will enhance your understanding of disease determinants and public health practices.
