Epidemiology Flashcards
What makes global mental health multidisciplinary?
It draws upon
- social sciences
- clinical disciplines
What are the 3 roles of epidemiological methods?
- Quantify burden of disease
- Examine determinants of disease
- Evaluate interventions designed to prevent disease
Who was John Snow?
- Medical doctor
- ‘father of epidemiology’
What did John Snow suggest was the cause of the common cholera outbreaks (1849)?
‘It’s a water-borne disease’
What did John Snow do during the 1854 cholera outbreak?
> By talking to local residents, he identified the Broad Street pump in Soho as the most likely source of the disease
> He persuaded the council to disable the pump
-> the epidemic came to an end
> He demonstrated a link between the quality of the water source and cholera cases using statistics
What are the two key approaches to ascertain cause and effect?
- Inductivism
2. Refutionism
What does the inductivist approach consist of?
Bacon (17th century):
- observation leads to development of theory of the observed patterns
- Iterative: further observation leads to the development of more advanced theories
- number of times a pattern is replicated does not prove causality
- causality can not be directly observed
- > spurious notions of cause and effect
What does the refutionism approach consist of?
> Hume (18th century):
- uncertainty between cause and effect relationship was impossible to eliminate
> Popper (20th century):
- scientific knowledge is generated as a result of this uncertainty
- role of observation is to attempt to criticise and refute existing theories
- > building scientific knowledge
Which approaches does modern science use to determinate cause and effect?
- Inductive (hypothesis generation)
- Deductive (hypothesis testing)
-> inductivist and refutionist approaches
How are the inductive and deductive processes of modern science used in epidemiology?
- Ideas for exploratory research often emerge from clinical observations
- Results from studies lead to generate of hypothesis that might be tested in later research
What characterises a hypothesis?
- Iteratively builds corroboration for theories by seeking evidence to refute them
- Central to all scientific practice (including epidemiology)
- It is a statement predicting an outcome
- Commonly emerges from inductive research
What are the three criteria that make a hypothesis?
- Clearly stated
- Testable and refutable
- Statement, not a question or objective
What are the advantages procured by hypotheses?
- Support validity of findings
- Less risk of type 1 error (false positive)
- Ease of replication of findings by others
- Ensures research is driven by theory and observation
- Ensures research is a scientific process (rather than ad-hoc or data-driven)
What are the three types of epidemiological studies?
- Descriptive epidemiology
- quantify the burden of disease
(e. g. cross-sectional studies) - Analytical epidemiology
- examine determinants of disease, course and outcome
(e. g. cohort studies) - Evaluative epidemiology
- evaluate efficacy and effectiveness of interventions
(e. g. RCTs)
How do hypotheses help us structure our research practice?
Hypotheses shape methodology
- design and outcome measures
- statistical analysis plan
What are the three key observational study designs used in global mental health research?
- Cross-sectional
- Longitudinal (cohort)
- Quasi-experimental
What does the 10/66 dementia research group study consist of?
Dominican Republic
- series of cross-sectional surveys examining the health of older people
Research questions:
- how does this vary across time?
- how does this vary between regions?
How is the analysis conducted in cross-sectional studies?
> Participants recruited at one particular point in time
> Data collected at single timepoint
- face-to-face, clinical, census records
Why are we provided with a ‘snapshot’ of the data in cross-sectional studies?
Data for baseline characteristics and outcomes are ascertained at the same time
-> ‘snapshot’
What type of data is collected in cross-sectional studies?
- Frequency
- Characteristics
- Distribution of outcomes
What are cross-sectional studies useful for?
- Planning services
- Raising awareness
- Comparing regions/time
- Identify association with risk factors
(e. g. weight loss and dementia) - gather evidence to support generation of hypotheses for future investigation using different study design
What is the limit of cross-sectional studies?
We cannot be sure of the direction of cause and effect
What does the ‘snapshot’ of current disease cases represent in cross-sectional studies?
A reflection of survival and aetiology of disease
How is the prevalence calculated?
Rate of new cases (incidence)
+ rate of cases disappearing (recovery, death, new diagnosis)