Epidemiology and Statistics Flashcards
What are the 2 main types of research studies?
Experimental (e.g. RCT) - random allocation of treatment to groups of matched people. “outcome vs control”
Observational (case-control. cohort) - no intervention, observation of attitudes or disease prevalence. Provides association between risk and outcomes
What are the main benefits of a cohort study?
- prospective design: timing of risk factors and disease progression
- population-based sample of people
What are the drawbacks of cohort studies?
- Confounding variables = causation cannot be determined
- long time to do
- expensive
- failure to follow up = bias
- participant behaviour/epidemiology is not linear and may change over time
- disease must be RARE
What are the issues with using sampling to estimate for a population?
- often leads to error
- population may be difficult to identify
- ideal sample size needs to be calculated (power calculation)
- results are generalised to population
- sampling techniques may vary
What is “complex sampling?”
Selection of natural clusters of participants (= administrative units) chosen out of convenience
What is the difference between mortality and morbidity?
Mortality: looks at categories of disease cause (neoplastic, circulatory, respiratory)
Morbidity: the impact of this disease on resources and interaction with doctor etc.
must consider clinical iceberg phenomenon
What are the implications of the “clinical iceberg” phenomenon?
- prevalence of common disease is underestimated
- average severity of morbidity is overestimated
- could result in being largely undiagnosed, due to often much milder symptoms
What are the main things to consider when using a “population approach?”
Remember WHO is at risk?
- persons (age, sex, ethnicity, social class)
- places (global, national)
- time (different decades, years)
What is a “cause” in epidemiological terms?
A factor that itself results in direct increase in disease risk
How is a “causal factor” identified?
Must be determined at population level (not possible at individual level)
must be variations between exposed and control groups (without disease)
What is epidemiology?
Study of the distribution and determinants of disease and health in human populations
What does public health include?
science + art in population:
- preventing disease
- promoting health
- prolonging life
What does clinical epidemiology comprise?
Application into clinical practice for:
- Dx
- causes
- Prognosis of disease
- Most effective treatment
What is the purpose of disease rates?
Link between individual cases to risk population at large
Rate = # of cases/population at risk
What are the differences between disease prevalence and incidence?
Incidence = # of new cases of disease Prevalence = presence of new and old disease
