Epidemiological Study Designs
Epidemiology is driven by data and usually relies on the collection of information and the analysis and interpretation of that information. Researchers in epidemiology are interested in the constant measurement or assessment of the relationship between exposure and disease/outcome. The study designs can be classified as observational or experimental depending on the approach used to assess the association between exposure and outcome.
For the Unit III Case Study, research and describe one experimental study design and one observational study design, and provide at least one example of how each design can be used in a research intervention.
Explain how one of these studies can be applied to one of the health problems you identified in your community. Provide a statistical table of the health problem you identified in your community (prevalence, incidence, mortality rates, and morbidity rates). This information is usually found in the local departments of health websites. Explain whether the health problem in your community is an endemic, epidemic, or pandemic.
Your case study must be a minimum of three pages in length, excluding the title and reference pages. To support your ideas, use a minimum of three outside sources; one may be the textbook. Additionally, use a source that focuses on your community, such as a newspaper or journal article.
Remember that all written assignments must be formatted using APA style, including in-text citations and references.
Epidemiological Study Designs
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What is one experimental study design?,
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What is one observational study design?,
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How can each design be used in research?,
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How can one design be applied to a health issue in your community?,
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What are the prevalence, incidence, mortality, and morbidity rates of that health issue?
- Epidemiological Study Designs
🧠General Comprehensive Answer:
1. Experimental Study Design – Randomized Controlled Trial (RCT)
An experimental study design actively assigns exposures or interventions to study participants. The Randomized Controlled Trial (RCT) is considered the gold standard of experimental design. Participants are randomly assigned to either the intervention group or the control group. This minimizes bias and allows for strong causal inferences about the effect of an exposure or treatment.
Example: An RCT can be used to test the effectiveness of a new diabetes prevention program among at-risk adults. Participants would be randomly assigned to either receive the intervention (e.g., lifestyle coaching and dietary planning) or to a control group receiving standard care. Outcome measures might include incidence of type 2 diabetes over one year.
2. Observational Study Design – Cohort Study
An observational study design involves monitoring participants without assigning treatments. The cohort study follows groups with differing exposures over time to determine the incidence of a specific outcome. It can be prospective or retrospective.
Example: A prospective cohort study could follow smokers and non-smokers for ten years to assess the incidence of lung cancer. Researchers would track exposure (smoking status) and outcome (cancer diagnosis) over time.
3. Application to a Local Health Problem – Type 2 Diabetes
Local Application Example:
Let’s apply the cohort study design to the rising rates of type 2 diabetes in Jefferson County, Alabama (a representative example). This community has reported high obesity rates, low physical activity, and limited access to fresh food—all contributing risk factors to diabetes. By following a cohort of overweight adults in Jefferson County over time, researchers could measure the incidence of type 2 diabetes and identify contributing lifestyle factors. This could lead to targeted, evidence-based interventions.
📊 Statistical Table – Diabetes in Jefferson County, AL (Sample Data)*
| Metric | Value |
|---|---|
| Prevalence | 14.8% |
| Incidence Rate | 10.2 per 1,000/year |
| Mortality Rate | 21.5 per 100,000/year |
| Morbidity Rate | High (linked with obesity, hypertension, and cardiovascular disease) |
*Note: Data sources may include the Alabama Department of Public Health and CDC’s BRFSS (Behavioral Risk Factor Surveillance System).
🌍 Endemic, Epidemic, or Pandemic?
Type 2 diabetes in Jefferson County is endemic—it is consistently present at elevated levels over time. It does not occur suddenly or spread rapidly like an epidemic, but rather persists due to systemic issues like poor diet, lack of physical activity, and socioeconomic factors. Unlike pandemics, it is localized and does not affect global populations simultaneously.
đź“š References (Sample APA Style):
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Centers for Disease Control and Prevention. (2023). Diabetes data & statistics. https://www.cdc.gov/diabetes/data/
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Alabama Department of Public Health. (2022). Chronic disease indicators for Jefferson County. https://www.alabamapublichealth.gov/
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Friis, R. H., & Sellers, T. A. (2021). E