Public health Flashcards
What is a case control study?
A group with a specific outcome is chosen, and then a group of controls to match are also found and they are analysed against each other.
Name 3 advantages for case control studies.
Good for rare outcomes
Quicker (as they already have the outcome)
Can investigate multiple exposures
Name 2 disadvantages of case control studies.
Difficulties matching cases with controls
Prone to selection and information bias
What is a cohort study?
Takes a group of people with a specific trait. Follows them up over a period of time to see whether they develop a specific outcome.
Name 3 advantages of a cohort study.
Follow up rare exposure
Good for common and multiple outcomes
Less risk of selection and recall bias
Name 3 disadvantages of a cohort study.
Long time
Loss to follow up
Need a large sample size
What is a crossectional study?
Analysis of data from a specific point in time.
Name 4 advantages of a cross sectional study.
Quick and cheap
Data on a single point in time
Large sample size
Good for surveillance and public health planning
Name 3 disadvantages of a cross sectional study.
Risk of reverse causality
Cannot measure incidence
Recall bias and non-response
What is a randomised control trial?
Clinical trials used to control factors which are not usually under direct experimental control
Name 2 advantages of RCT’s
Low risk of bias and confounding
Can infer causality
Name 3 disadvantages of RCT’s
Time consuming
Expensive
Study population may be different to typical patients.
What is selection bias?
Systemic error in selection of study participants. e.g. non-response those who don’t respond to postal surveys more likely to be unwell, elderly, low socioeconomic status etc
What is the health belief model of behaviour change?
Patient believes they are susceptible to the condition (e.g. heart disease)
Believes that it has serious consequences
Believes that taking action reduces susceptibility
Believes that the benefits of taking action outweigh the costs
What are the critiques with the health behaviour model?
Alternative factors may predict health behaviour i.e. if a person feels they will be healthier as a result of their behaviour
This model does not consider the influence of emotions on behaviour
What is the theory of planned behaviour?
Proposes the best predictor of behaviour is the intention to do something
What three things is an intention determined by in the theory of planned behaviour?
Persons attitude to the behaviour
Perceived social pressure to undertake the behaviour
A persons appraisal of their ability to perform the behaviour
What is the transtheoretical model of behaviour change?
It proposes 5 stages of change:
Not ready yet, thinking about it, getting ready, doing it, maintenance.
What are the advantages of the transtheoretical model?
Acknowledges individual stages of readiness
Accounts for relapse
What are the critiques of the transtheoretical model?
Not all people move through every stage.
Change may operate on a continuum rather than in discrete stages
What is the definition of malnutrition?
Deficiencies, excesses or imbalances in a person’s intake of energy or nutrients
What is the definition of primary prevention?
Action takes to prevent disease before it occurs
What is the definition of secondary prevention?
Designed to reduce the progression of a disease/ catch it in the early stages such as a screening programme
What is the definition of tertiary prevention?
Reducing the impact of established disease by reducing disability, minimising suffering and maximising quality of life.
What is equity?
What is fair and just
What is equality?
Concerned with equal shares
What is horizontal equity?
Equal treatment for equal need
What is vertical equity?
Unequal treatment for unequal need. i.e. more funding in areas with poorer health
What are the 2 categories of dimension of health equity?
Spatial (geographical) and social (age, gender, class, ethnicity)
What are the 3 domains of public health practice?
Health improvement
Health protection
Health care
What is health improvement?
Concerned with societal interventions, such as reducing inequalities and increasing access to education
What is health protection?
Concerned with measures to control infectious disease risks and environmental hazards
Give an example of an individual level intervention?
Childhood immunisations
Give an example of a community level intervention.
New playground for the local community
Give an example of an ecological level intervention.
Ban on smoking indoors
What is a health needs assessment?
Systematic method for reviewing the health needs facing a population, leading to agreed priorities and resource allocation that will improve health and reduce inequalities
What types of things can a health needs assessment be carried out on?
Population or subgroup
Condition
An intervention
What is felt need?
Individual perceptions of variation from normal health
What is expressed need?
Individual seeks to overcome variation in normal health
What is normative need?
Professional defines intervention appropriate for the expressed need.
What is comparative need?
Comparison between severity, range of interventions and cost
Describe the epidemiological approach to health needs assessment.
Define the problem, look at the size of the problem, what is already available, are needs being met, give recommendations.
What are the problems with an epidemiological health needs assessment approach?
Required data might not be available
Variable data quality
Evidence base may be inadequate
Does not consider the felt needs of people affected
What is a comparative approach to a health needs assessment?
Compares the services that one population receives compared to another.
Looks into, health status, service provision, service utilisation, health outcomes etc.
What are the problems with a comparative model of health needs assessment?
May not yield what the most appropriate level of provision is.
May be difficult to find a comparable population
What is a corporate approach to health needs assessment?
Obtaining views from a range of stake holders such as: Commissioners, providers, professionals, patients, relatives and carers
What are the problems with a corporate approach to health needs assessment?
Difficult to distinguish need from demand
Groups may have vested interest
May be influenced by politics
Dominant personalities may have undue influence
What are the 3 main parts of a health service evaluation?
Structure
Process
Outcome
What are the 3A’s and 3E’s to assess the quality of healthcare?
Acceptability
Accessibility
Appropriateness
Effectiveness
Equity
Efficiency
What are qualitative methods of evaluation of health services?
Consult the people using the service, such as patients, staff relatives
Conduct interviews
Focus groups etc
What are quantitative methods of evaluation of health services?
Routinely collected data
Review records
Surveys
Patient satisfaction records
What is the definition of epidemiology?
The study of frequency, distribution and determinants of diseases and health related states in populations in order to prevent and control disease
What is incidence?
The new cases
What is prevalence?
The existing cases at a point in time
What is absolute risk?
Gives an actual number: 50 deaths per 1000 cases
What is relative risk?
Risk in one category relative to another
What is attributable risk?
The rate of disease in the exposure that can be attributed to that exposure. So, you subtract the risk of it just occurring anyway.
What is selection bias?
A systematic error in the selection of study participants or the allocation of the participants to different study groups.
What is observer bias?
i.e. different nurses think differently so have different approach to study
What is participant bias?
Recall bias, so patient cannot remember correctly, so may give you factually incorrect informaation
What is participant bias?
Recall bias, so patient cannot remember correctly, so may give you factually incorrect information
What is instrument bias?
Different BP machines calibrated to a different level.
What is a confounder?
A factor associated with the exposure of interest and independently influences the outcome but does not lie on the causal pathway.
What is a cohort study?
A longitudinal study that samples a particular population who share a defining characteristic to see if they develop a particular outcome
What is a case control study?
A group of people already with the desired outcome are analysed against a similar group without the outcome
What is a randomised control trial?
Similar people are assigned to 2 groups, a control and a test group. Designed to test a drug, treatment or other intervention
What is a cross sectional study?
Collect data from a single point in time. I.e. working out how many people have a certain disease within a population at a certain time
What is an ecological study?
A study that compares large groups of people for differences, e.g., rates of COPD in Sheffield vs Leeds.
What is a population approach to prevention?
Dietary salt reduction through legislation and working with the food industry
What is a high-risk approach to prevention?
Identify individuals above a chosen cut off and treat them
What is a prevention paradox?
A preventative measure which brings much benefit to the population but often brings little benefit to the individual.
What are the Wilson and Junger criteria for screening?
The condition being screened for should be an important health problem
The natural history of the condition should be well understood
There should be a detectable early stage
Treatment at an early stage should be of more benefit than at a later stage
A suitable test should be devised for the early stage
The test should be acceptable
Intervals for repeating the test should be determined
Adequate health service provision should be made for the extra clinical workload resulting from screening
The risks, both physical and psychological, should be less than the benefits
The costs should be balanced against the benefits
What is sensitivity?
The proportion of people with the disease who are correctly identified by the screening test
What is specificity?
The proportion of people without the disease who are correctly excluded by the screening test.
What is the positive predictive value?
The proportion of people with a positive test who actually have the disease
What is the negative predictive value?
The proportion of people with a negative test who actually don’t have the disease
What is length time bias?
Less aggressive cancers are more likely to be picked up as people live for longer with them
What is point prevalence?
Number of cases of disease at a point in time
What is period prevalence?
Number of cases of disease at any time during a specified time period
What is cumulative incidence?
Number of new cases of disease in a specified time period/ number of disease free people at the start of time period
What are incidence odds?
The probability of getting the disease by the end of the time period/probability of not getting the disease by the end of the time period
