Zusammenfassung der Ressource
Observational
Study Designs
- Non experimental
- effective for investigating causal
links between exposures and
disease
- more susceptible to bias and confounding
compared to randomised control trials.
- 'non-intervention' studies that are
conducted as people go about
their daily life.
- Types
- Analytical
- cohort studies, case-control, or analytical surveys
- cross-sectional surveys
- examine relationships between variables (e.g. 'Does
alcohol consumption increase the risk of breast
cancer?').
- Descriptive
- case reports, case series and
simple surveys
- more commonly used to measure
the incidence and prevalence of risk
factors or disease
- ANALYTICAL
- Cohort Studies
- longitudinal in design, start with a selected group of
disease-free people who are classified according to
specific exposure (e.g. high/low alcohol consumption
- study group is followed over time to see who
develops the disease/outcome (e.g. breast cancer).
- used to measure incidence (new cases of disease) and thus risk.
- Analyse results
- relative risk (RR)
- odds ratios (OR).
- represent the increased (or
decreased) risk of disease for
those in the exposed group
- Examples of questions
- 3.Does smoking increase the risk of
lung cancer and other diseases?
- 4.Does breast-feeding play a role in breast cancer?
- 1.Does physical activity reduce the risk of
heart disease?
- 2.Do high levels of HDL cholesterol reduce the
risk of coronary death?