Public Health Flashcards
Name the 3 domains of public health (3)
- Health Improvement
- Health Protection
- Improving Services
What is the “Health Improvement” domain of PH? (+ 5 examples)
“Social interventions aimed at preventing disease, promoting health and reducing inequalities”
- Inequalities
- Education
- Housing
- Employment
- Lifestyles
Define the “Improving Services” domain of PH (+5 examples)
“Organisation and delivery of safe high quality services for prevent, treatment and care”
- Clinical effectiveness
- Efficacy
- Service Planning
- Audit Evaluation
- Clinical Governance
Define “Horizontal Equity” (1)
“Equal treatment for equal need”
To understand this think of taxation - Horizontal equity is saying people who have the same income (equal need) should pay the same taxes (equal treatment). Or that people with the same disease should receive the same treatment quality etc..
This is not mutually exclusive from vertical equity, both can occur together btw
Define “Vertical Equity” (1)
- “Unequal treatment of unequal need”
Basically, like with taxes, if you earn more (unequal need) you should pay more (unequal treatment) than someone who earns less. Note that horizontal equity should really co-exist here. Its not either-or, for example higher earners should pay more than lower earners (Vertical) but within each bracket of pay, identical incomes should pay identical taxes (horizontal)
Outline the Bradford Hill Criteria for Causation (6)
What’s the point? Basically these criteria increase the chance that the causality “seen” in data is actual causality:
1.Temporality - exposure is prior to outcome?
- Dose Response - Increased outcome with increased
exposure - Strength - Strong association between exposure and
outcome - Reversibility - removal/reduction of exposure
mirrored in outcome - Consistency - replicatable results by other studies
- Biological Plausibility - reasonable mechanism
proposed
(+ coherence - agrees with literature, analogy, specificity) - don’t bother here
A paediatric consultant is conducting research to investigate whether the diet of
children in their first year of life is associated with their subsequent risk of food allergy.
Parents of children aged 5-10 years with and without food allergies are asked to
complete a questionnaire about their child’s diet between the ages of 6 months and 1
year (i.e. a case-control study). What Bias may influence this approach? (1)
- Recall Bias - parents asked to remember events years ago
List 5 things associations in data can be due to (other than causality) (5)
- Bias
- Confounding Factors
- Chance
- Reverse Causality
- True Association
List the 3 types of Bias (3)
- Selection Bias
- Information Bias
- Publication Bias
obvs more exist but these are the PH ones needed
Define “Selection Bias” (1)
- A systemic error in the SELECTION of participants or the ALLOCATION of participants to certain study groups
Define “Information Bias” and list 3 causes (4)
- Systemic error in the measurement of classification of exposure or outcome data.
CAUSES:
2. Observer Bias - human error/observer incompetency
- Participant Bias - e.g. Memory or Recall Bias
- Instrument Bias - Poorly calibrated Instrument
Define “Publication Bias” (1)
- Trials with negative results and replication studies are less likely to be published
What is “Lead-Time Bias” (1)
- (Mainly relates to screening) Screening for a disease may pick it up way before it would normally clinically manifest. This extra time where the patient knows they have the Dx without yet having symptoms is known as LEAD TIME. Even though Early detection might not alter prognosis at all, the screening programme APPEARS to improve survival time simply because you knew about the Dx early.
What is “Length Bias” (1)
- (Mainly for screening) Basically, it refers to the fact that Chronic or Slow-progressing illness is more likely to be picked up by screening whereas short-course illness isn’t as the length of illness is so short it may have happened lots in the population but not been picked up at the single time point you investigate with screening - eg many cases have either died or recovered either side of screening. As Chronic disease lasts longer, more will be present at any one time point in the population, appearing to increase its prevalence when compared to an equally prevalent short-term illness.
Define Confounding (1)
- When an apparent association between two factors is actually the result of a separate factor affecting both variables
Is a Randomised Control Trial Prospective or Retrospective? (1)
- Prospective
Is a Cohort study Prospective or Retrospective? (1)
- Prospective
Is a Case-Control study Prospective or Retrospective? (1)
- Retrospective
Is a Cross-Sectional study Prospective or Retrospective? (1)
- Retrospective
Is a Case Series study Prospective or Retrospective? (1)
- Retrospective
Is a Case Report study Prospective or Retrospective? (1)
- Retrospective
Outline the Structure of a Cross Sectional Study (3)
- Retrospective OBSERVATIONAL study
- Collects data from a population at a SEPCIFIC time
- Produces data on PREVELANCE of RISK FACTORS and DISEASE
List 3 advantages of a Cross-Sectional Study Design (3)
- Large Sample Size possible
- Rapid
- Repeated Studies can show changes over time (eg by taking repeated “cross sections”)
List 3 disadvantages of Cross Sectional Studies (3)
- Risk of Reverse Causality (which came first??)
- Disease Length Bias - (won’t include rapid recoveries)
- Sample size too small for rarer outcomes / diseases
Outline the Structure of a Case-Control Study (2)
- Retrospective study looking back at a Cohort WITH a disease and a cohort WITHOUT/control population
- Looks for the CAUSE of a disease by trying to identify differences between the two cohorts
List 2 Advantages of a Case Control Study (2)
- Good for rare outcomes
- Rapid
List 2 Disadvantages of a Case Control study (2)
- Prone to Selection Bias and Information Bias
- Resource consuming to find well matched populations
Outline the Structure of a Cohort Study (2)
- Prospective longitudinal study looking at separate cohorts with different treatments or exposures applied
- Basically waiting to see what will happen, u basically follow two different cohorts up to see if a treatment of exposure changes anything but you haven’t literally given the intervention
List 3 Advantages of a Cohort Study (3)
- Can establish disease Risk Factors without risk of reverse causality (as disease hasn’t happened yet)
- Can follow rare exposures
- Data on confounders can be collected prospectively
List 3 Disadvantages of a Cohort Study design (3)
- Difficult to assess rare diseases as they may not develop
- Drop outs are common as it is prospective
- Large Sample Size required - expensive and time consuming
Outline Structure of an RCT (2)
- Prospective Interventional Study
- U randomly give populations an intervention and see what happens
List 3 Disadvantages of RCTs (3)
- Ethical issues - eg is it ethical to give a population treatment you don’t think will work? may cancel trial if one group see incredible improvements or side effects for example
- Drop Outs
- Expensive and time consuming + lots of regulation and hoops to jump through
Outline the structure of an Ecological Study
- Comparative, Population Based data (instead of individual)
It is comparative in two main ways:
2. Geography: Outcomes at GP practice A vs B
- Time trends: Covid cases/time
What type of study design was used? (1)
“Investigators found a high level of correlation between socioeconomic deprivation and IHD mortality across electoral wards in the UK”
- Ecological
Compares population level data across geographical regions
What type of study design was used? (1)
“Researchers set out to examine the association between alcohol consumption and stroke. They identify all new patients admitted with stroke and compare alcohol consumption with patients admitted for any elective surgery”
- Case-Control Study
Because they’re looking at patients ALREADY WITH disease and looking BACKWARDS to identify the risk factors for it. I originally though Cohort study, but that’s because i forgot this is retrospective. The Stroke has ALREADY HAPPENED. Cohort would be looking forward after alcohol consumption to see who then got a stroke later.
What type of study design was used? (1)
GPs set up a study to assess prevalence of Depression in their community. They start with a random sample of adults aged 40 - 65
- Cross-sectional
They’re assessing PREVALENCE at a SPECIFC POINT IN TIME
List the 4 types of Health Needs outlined in Bradshaw’s Needs (4)
- Felt needs
- Expressed Needs
- Normative Needs
- Comparative Needs
“FENC”
Define “Felt Needs” from Bradshaw’s Needs (1)
- Individual perceptions of variation from normal health
eg a perceived illness or upset by the patient
Define “Expressed Needs” from Bradshaw’s Needs (1)
- The seeking of help - Individual seeks help to overcome the variation in normal health
(the “Demand” bit from the “Need, Demand, Supply” triad)
Define “Normative Needs” from Bradshaw’s Needs (1)
- Professional Defines the Intervention appropriate for the expressed need