Epidemiology 1

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Questions and Answers

Which form of bias occurs when the sample population does not accurately represent the larger population?

Selection Bias (correct)

Causal Bias

Measurement Bias

Response Bias

What type of bias arises from errors in how data is collected or measured?

Survivorship Bias

Measurement Bias (correct)

Sampling Bias

Confounding Bias

Which of the following represents a confounding factor in a study examining the effect of physical activity on depression?

The timing of the survey administration

Dietary habits of the participants (correct)

The measurement of physical activity levels

The method of analysis used

In determining causation from an observed association, which of the following must be considered?

Bias Types Signup and view all the answers

What does the concept of reverse causation imply in epidemiological studies?

The outcome happens before the exposure Signup and view all the answers

What is primarily introduced by the investigator during a study that is not intentionally meant to skew results?

Bias Signup and view all the answers

What method is employed to minimize the effects of confounding in a study design?

Restriction Signup and view all the answers

Which type of bias occurs when the method of selecting participants results in a misrepresentation of a population?

Selection bias Signup and view all the answers

What is an example of a confounding variable that could affect the outcome of a study?

A participant's age Signup and view all the answers

What is the primary difference between observational and experimental study designs?

Whether the investigator assigned the exposure Signup and view all the answers

Which of the following is NOT a type of bias that can occur in study designs?

Confounding bias Signup and view all the answers

In a case-control study, what is the primary starting point for the research?

Case status Signup and view all the answers

How does a longitudinal study help in addressing the issue of reverse causality?

It follows individuals over time to observe outcomes. Signup and view all the answers

Which Bradford-Hill consideration emphasizes that the exposure must precede the outcome for a causal link?

Temporality Signup and view all the answers

What type of study is mainly concerned with assessing frequency and distribution of diseases at a specific point in time?

Cross-sectional study Signup and view all the answers

What is selection bias?

Bias that occurs when the sample is not representative of the population. Signup and view all the answers

Which of the following is an example of measurement bias?

A researcher who subconsciously influences participant responses. Signup and view all the answers

Which statement about confounding factors is true?

A confounder is related to both the exposure and the outcome. Signup and view all the answers

How does sample size affect confidence intervals?

Larger samples narrow the confidence interval and reduce p-values. Signup and view all the answers

Which of the following errors represents a Type 1 error?

A statistically significant result that occurs by chance. Signup and view all the answers

What characterizes observer bias?

Unintentional reporting errors influenced by the observer's knowledge. Signup and view all the answers

How can selection bias affect study results?

It leads to an untrue estimation of the association being measured. Signup and view all the answers

What does a confidence interval that crosses 1 indicate?

Failure to reject the null hypothesis. Signup and view all the answers

Which method can help control confounding in studies?

Collecting data on potential confounders during study design. Signup and view all the answers

Which of the following describes recall bias?

Participants' inability to remember past exposures accurately. Signup and view all the answers

Study Notes

Core Principles of Mental Health Research

Epidemiology research examines the history of both epidemiology and psychiatry to understand disease frequency. It looks at key investigation methods like chance, bias and confounding and reverse causality.
Investigating causes: Physical activity is hypothesized to reduce depression risk. A cross-sectional survey is a study design used for this investigation. Outcomes and exposure are depression and physical activity. This research method looks at data gathered at one point in time. Data from labs, disease surveillance, case reports, and theoretical reasoning are used to investigate this relationship

Epidemiological Reasoning

Study design includes identifying the research question, collecting data systematically, analyzing it systematically, and interpreting the results.
Assessing validity and making inferences from associations is key. Determining if a relationship is causal involves considering chance, bias (selection and measurement), and confounding. Reverse causality needs to be considered; for example, depression may cause less exercise, not the other way around.

Making Inferences from Epidemiological Observations

Using statistical methods is necessary to gauge the impact of chance. Confidence intervals and p-values help in this process. Sample size is important, as well as a defined sampling strategy that adequately generates a statistically robust population inference.
Bias is systematic error introduced during the study design or conduct, which affects the validity of the study results. Selection bias arises during individual selection procedures for studies. Measurement bias refers to issues in measuring the exposure, outcome, or other information on participants. Confounding presents an alternate explanation for the relationship between an exposure and an outcome. Using methods like randomisation strategies, and adjusting for confounding variables are crucial to address this. Residual confounding may occur even after adjusting for known confounders.

Models of Causation

The causality of a disease does not need to be sufficient or necessary. The example given is that smoking is not always the cause of disease, and smoking does not always cause disease.
Bradford Hill's considerations for causality include temporality (exposure before outcome), strength of the association, dose-response relationship, consistency in studies, specificity, coherence, plausibility, and experimental studies.
There are different types of epidemiological studies: descriptive; and analytical (case-control and cohort studies).
- Descriptive epidemiology: observational research. Example studies include ecological studies (looking at populations).
- Analytical epidemiology: observational and experimental (case-control, cohort and intervention studies).

Strengths and Limitations

Different study designs have varying degrees of strength and limitations for determining causal inferences from epidemiological studies and experiments. The study designs discussed include cross-sectional and longitudinal study designs. The strength of a study design depends on sampling strategy, measurements used, the study design itself, and issues with confounders and adjustments for confounders. Randomised controlled trials are considered the strongest, and ecological studies as having weak causal inferences.

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Description

This quiz explores the foundational concepts of mental health research, focusing on the role of epidemiology in understanding disease frequency. It covers various investigation methods, study designs, and the relationship between physical activity and depression, providing insights into validity and causal relationships.