A Brief Introduction to Epidemiology VIII Epidemiologic Research Designs: CrossSectionalPrevalence S

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A Brief Introduction to Epidemiology -
VIII(Epidemiologic Research Designs
Cross-Sectional/Prevalence Studies)

• Betty C. Jung, RN, MPH, CHES

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Learning/Performance Objectives

• To develop an understanding of
• What cross-sectional studies are
• The value of such studies
• The basic methodology
• Pros and cons of such studies

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Introduction

• Epidemiology studies the distribution of disease
  in a number of ways.
• The two major categories of epidemiological
  studies are Observational and experimental
  studies.
• Most epidemiological studies are observational.

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Epidemiological Study Designs

• Observational Studies - examine associations
  between risk factors and outcomes (Analytical -
  determinants and risk of disease, and descriptive
  - patterns and frequency of disease)
• Intervention Studies - explore the association
  between interventions and outcomes. (Experimental
  studies or clinical trials)

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Research Designs in Analytic Epidemiology

• Ecologic Designs Cross-Sectional Study
• Case-Control Study
• Cohort Study

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Cross-Sectional Studies

• Snapshot Studies (Paffenbarger, 1988)
• Observations at a single hypothetical point in
  time
• Each subject assessed once at point in time.
• Point Prevalence Studies

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Examples

• National Health Nutrition Examination Surveys -
  allow for current estimates of prevalence for
  health parameters
• Youth Risk Behavior Surveys - prevalence of prior
  health-risk behaviors

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Value

• Observe high prevalence of risk factors in those
  with disease
• Suggests possibility of certain risk factors as
  cause of common disease
• Quantify with point prevalence rates

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Value

• Cannot tell why any health differential exist,
  but that they do exist
• Good for generating hypotheses about the cause of
  disease
• Can be used to initiate and evaluate effective
  health services programs
• Most commonly used strategy

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Pros

• One time exam/interview
• Good for program and service planning
• To determine associations between variables and
  generate hypotheses
• Description of relative distribution, directs
  case finding

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Cons

• Cannot predict future health event happenings
• Limited usefulness for outbreak and epidemics
• Does not allow to determine which came first
• Only describes what exist at time of study

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References

• For Internet Resources on the topics covered in
  this lecture, check out my Web site
• http//www.bettycjung.net