Public Health Peer Teaching Flashcards
What are the 3 domains of Public Health?
- Health improvement
- Health protection
- Improving services
Give examples of ‘Health improvement’ as applied to Public Health
- Inequalities
- Education
- Housing
- Employment
- Lifestyles
- Family / community
Give examples of ‘Health Protection’ as applied to Public Health
- Infectious disease
- Chemicals and poisons
- Radiation
- Emergency response
- Environmental health hazards
Give examples of ‘Improving services’ as applied to Public Health
- Clinical effectiveness
- Efficiency
- Service planning
- Audit + evaluation
- Clinical governance
- Equity
What influences health inequalities?
‘PROGRESS’
- Place of residence (rural, urban)
- Race (or ethnicity
- Occupation
- Gender
- Religion
- Education
- Socioeconomic status
- Social capital or resources
What is the difference between equality and equity?
Equity: giving everyone what they need to be successful
Equality: treating everyone the same
What is ‘Horizontal Equity’?
Give an example.
‘equal treatment for equal need’
-> all people with pneumonia deserve equal treatment, all else being equal
What is ‘Vertical Equity’?
Give an example.
‘unequal treatment for unequal need’
- > individuals with pneumonia deserve different treatment from those with common cold.
- > areas with poorer health may need higher expenditure on health services
What is a cohort study?
- Longitudinal study in similar groups but with different risk factors / treatments
- > follows up over time
List 3 advantages of a cohort study.
- can follow up rare exposure
- allows identification of risk factors
- data on confounders is collected prospectively.
List 4 disadvantages of a cohort study.
- Large sample size required
- Impractical for rare diseases
- Expensive
- People drop out
What is a case control study?
- Observational study looking at cause of a disease
- compares similar participants with disease and controls without
- Looks retrospectively for exposure / cause
List 2 advantages of a case control study.
- Quick
- Good for rare outcomes
List 2 disadvantages of a case control study.
- Difficult finding appropriately matched controls
- Prone to selection and information bias
What is a cross sectional study?
- Observational study collecting data from a population at a specific point in time
- A snapshot of a group
List 4 advantages of a cross sectional study.
- Large sample size
- Provides data on prevalence of risk factors and disease
- Quick to carry out
- Repeated studies show changes over time
List 3 disadvantages of a cross sectional study.
- Risk of reverse causality -> which came first?!
- Less likely to include those who recover quickly or short recovery.
- Not useful for rare outcomes.
What is a randomised control trial?
Similar participants are randomly assigned to an intervention or control group to study the effect of the intervention.
List 2 advantages of an RCT.
- Low risk of bias and confounding
- Comparative
List 3 disadvantages of an RCT.
- Hight soup out rate, little incentive to stay in control group arm
- Ethical issues
- Time consuming and expensive
- Prior knowledge required
Define ‘incidence’.
Number of new cases in a population during a specific time period.
Define ‘prevalence’.
Number of existing cases at a specific point in time.
Over a 10 year period, there were 50 new cases of lung cancer in Crookes (a population of 1,000 people). What is the incidence of lung cancer over those 10 years?
50/1000 = 5%
In Crookes (population of 1000 people), 300 people smoke. Of those who smoke, 45 developed lung cancer. 5 of the non-smokers developed lung cancer. What is the relative risk of lung cancer in smokers?
Risk of lung cancer in smokers = 45 / 300 = 15%
Risk of lung cancer in non-smokers = 5/700 = 0.7%
Relative risk (ratio) = 15/0.7 = 21.4
So: 21.4 times more likely to develop lung cancer if a smoker.
Explain ‘attributable risk’ as applied to smoking + lung cancer.
Attributable risk = amount of lung cancer that is specifically due to smoking.
Subtract the ‘naturally occurring’ cases that ‘would have happened anyway’ from the number of cases in the exposed.
Risk of lung cancer in smokers = 15%
Risk of lung cancer in non-smokers = 0.7%
Calculate the attributable risk (risk difference).
15% - 0.7% = 14.3%
Attributable risk = 14.3%
In Crookes (population of 1000 people), 300 people smoke. Of those who smoke, 45 developed lung cancer. 5 of the non-smokers developed lung cancer.
The attributable risk is 0.143.
Calculate the number of people who would have to give up smoking to prevent one death from lung cancer.
Attributable risk = 0.143
NNT = 1/Attributable risk
= 1 / 0.143 = 6.99
=> If 7 people gave up smoking in this population, you would prevent one death from lung cancer.
*always round up a ‘number needed to treat’, as you can’t treat a fraction of a person.
Define ‘sensitivity’.
The percentage of people correctly identified with the disease
Define ‘specificity’.
The percentage of people correctly excluded as ‘disease free’.
What problem might arise if a test is 100% sensitive?
Correctly identifies everyone with the disease as having the disease, but may cause false positives.
What problem might arise if a test is 100% specific?
Correctly excludes everyone without the disease, but may miss people who do have the disease.
What is the ‘Positive predictive value’?
%age of those with a positive test who actually have the disease
What is the ‘Negative Predictive Value’?
%age of those with a negative test who are actually disease free
What is the criteria for a screening test?
- Important disease
- Natural history of the disease must be understood (detectable risk factors, disease markers)
- Simple, safe, precise and validated test
- Acceptable to the population
- Effective treatment from early detection with better outcomes than late detection
- Policy of who should receive treatment.
What can association be due to?
- Bias
- Chance
- Confounding
- Reverse causality
- True association