Public Health Flashcards
Define epigenetics
How the expression of a genome can be affected by the environment
Define allostasis
The process of achieving stability (homeostasis) through physiological or behavioral change
What is allostatic load?
Long-term overtaxation of our physiological systems leading to impaired health (stress)
Define salutogenesis
Favourable physiological changes secondary to experiences which promote healing and health
Define emotional intelligence
Ability to identify and manage one’s own emotions, as well as those of others
What is health?
Define public health.
State of complete physical, mental and social well-being (not merely absence of disease and infirmity)
Science and art of preventing disease, prolonging life and promoting health through organised efforts of society.
What are the 3 domains of public health?
Health promotion/improvement
Health protection
Improving services
What is the public health domain health promotion/improvement concerned with?
Lifestyle: Change4Life, NHS Quit smoking, Cough to 5K
Education
Employment
Housing
Surveillance and monitoring of specific diseases
What is the public health domain of health protection concerned with?
Measures to control: Infectious diseases Radiation Environmental disasters Emergency responses
Give an example of how Public Health England improves services?
Clinical effectiveness
Efficiency
Audit and evaluation
Clinical governance
What are the 3 key concerns of public health?
Inequalities in health
Wider determinants of health
Prevention
How can health interventions be applied?
Individual level (vaccines to prevent individual illness) Community level (opening new outdoor play area in town) Population level (iodine in salt to prevent iodine deficiency)
What needs to be carried out before a health intervention is made?
Health needs assessment
What is a health needs assessment?
Systematic method for reviewing the health issues facing a population
Leading to agreed priorities and resource allocation that will improve health and reduce inequalities
What are the 4 components of a health needs assessment?
Needs assessment
Planning
Implementation
Evaluation
What are the 3 different approaches of health needs assessments?
Epidemiological
Comparative
Corporate
Define need
Ability to benefit from an intervention
Define demand
What people ask for
Define supply
What is provided
What is a health need, and how is it measured?
A need for health
Measured using:
Mortality
Morbidity
Socio-demographic measures
What is a health care need?
The ability to benefit from health care
Depends on the potential for prevention, treatment and care services to remedy health problems
What are the 4 sociological perspectives of need (aka Bradshaw’s taxonomy of need)?
FENC
Felt: individual perceptions of variation from normal health
Expressed: individual seeks help to overcome variation in normal health
Normative: professional defines intervention appropriate for expressed need
Comparative: comparison between severity, range of interventions and cost
What does an epidemiological approach to a health needs assessment involve?
Define problem
Look at size of problem (incidence/prevalence)
Services available (prevention/Rx/care)
Evidence base (effectiveness and cost-effectiveness)
Models of care (quality and outcome measures)
Existing services (unmet need; services not needed)
Recommendations
Give some potential sources of data for an epidemiological HNA?
Disease registry Hospital admissions GP databases Mortality data Primary data collection (e.g. postal/patient survey)
Give 2 advantages of an epidemiological HNA?
Uses existing data
Provides data on disease incidence/mortality/morbidity, etc
Can evaluate services by trends over time
Give 2 disadvantages of an epidemiological HNA
Quality of data variable
Data collected may not be data required
Does not consider felt needs/opinions of people affected
What does a comparative approach to a HNA involve?
Compares the services received by a population/group with those received by a similar group
What factors might a comparative HNA examine?
Health status
Service provision
Service utilisation
Health outcomes (mortality, morbidity, QoL, patient satisfaction)
Give 2 advantages of a comparative HNA
Quick and cheap (if data available)
Indicates whether health/services provision is better/worse than comparable areas (gives measure of relative performance)
Give 2 disadvantages of a comparative HNA
Difficulty finding comparable population
Data may not be available/high quality
May not yield what the most appropriate level (e.g. of provision or utilisation) should be
What does the corporate approach to a HNA involve?
Ask local population what their health needs are
Uses focus groups, interviews, public meetings, etc
Wide variety of stakeholders (eg teachers, healthcare professionals, social workers, charity workers, local businesses, council workers, politicians)
Give 2 advantages of a corporate HNA
Based on felt + expressed needs
Recognises detailed knowledge and experience of those working with the population
Takes into account wide range of views
Give 2 disadvantages of corporate HNA
Difficult to distinguish ‘need’ from ‘demand’
Groups may have invested interests (biased)
May be influenced by political agendas
Define primary prevention and give an example
Preventing disease before it has happened
Eg Change4life, 5 a day
Define secondary prevention and give an example
Catching a disease in its early/ pre-clinical phase
Eg Breast screening programme
Define tertiary prevention and give an example
Preventing complications of a disease
Eg diabetic foot care, attending physio/rehab after a stroke to prevent immobility and aspiration pneumonia
What are the 2 general approaches to prevention?
Population approach (preventive measures, e.g. adding iodine to salt to prevent iodine deficiency; dietary salt restriction through legislation to reduce BP)
High risk approach (identifying individuals above a chosen cut-ff and treat, e.g. screening for HTN)
What is meant by prevention paradox?
Preventative measure which brings much benefit to the population often offers little to each participating individual
ie screening a large number of people to help a small number of people, e.g. enforcing the use of seatbelts
What is screening?
Process which picks out apparently well people who are at a risk of a disease, in the hope of catching the disease at its early stage
What are the Wilson and Hunger criteria needed for a screening programme?
1) Disease important problems
2) Recognisable early symptoms
3) Known progression of disease
4) Acceptable test
5) Treatment available
6) Agreed at-risk population to screen
7) Agreed policy on whom to treat
8) Cost < Benefit of screening
Give the 6 key types of screening
Population-based (eg breast cancer) Opportunistic (eg BP in GP) Communicable diseases Pre-employment and occupational medicals Commercially provided (eg genetic info) Genetic counselling (people with FHx disease)
Give 3 disdvantages of screening
- Exposure of well individuals to distressing or harmful diagnostic tests
- Detection and Rx of sun-clinical disease that would never have caused any problems
- Preventative interventions that may cause harm to the individual or population
What is sensitivity? How is it calculated?
Proportion of people with the disease who are correctly identified
a/a+c (a = true +ve; c = false -ve)
What is specificity? How is it calculated?
Proportion of people without the disease who are correctly excluded
b/b+d
What is the PPV and how is it calculated?
Proportion of people with a positive test result who actually have the disease
True positive / [true positive + false positive’
What is the NPV and how is it calculated?
How is it affected by prevalence?
Proportion of people with a negative test result who do not have the disease
True negative / [true negative + false negative]
NPV is lower if prevalence is higher
Define incidence?
Define prevalence?
Incidence = no. new cases in a population over a given time period
Prevalence = no. cases in a population at a specific point in time
What is meant by lead time bias?
Screening identifies outcome earlier that it would have otherwise been identified.
Results in apparent increase in survival time, even if screening has no effect on outcome
What is meant by length time bias?
Screening may identify more indolent diseases that have longer courses, but miss shorter more aggressive diseases. May affect the apparent efficacy of a screening method
What is a case control study? Advantage? Disadvantage?
Retrospective. Looks at people with a condition and matches them to people without the condition for age/sex/habitat, etc.
Study previous exposure to agent in question.
Good for rare outcomes and can investigate multiple exposures.
Susceptible to RECALL bias
What is a cohort study? Pros and cons?
Usually prospective. Looks at a population without the disease and studies over time to see whether exposed to agent in question and whether they develop the disease.
Absolute, relative and attributable risks can e calculated. Good for common outcomes.
Takes a long time. High drop out rate. Large sample size required.
What is a RCT? Pros and cons?
Patients randomised into groups - one given intervention, other given placebo. Outcome mreasured.
Confounding and biases minimised. Shows causation.
Time consuming, expensive, ethical issues (withholding treatment)
What is an independent variable?
What is a dependent variable?
A variable that can be altered in a study
A variable that is dependent on the independent variables, or one that cannot be altered
What is meant by the ‘odds’ of an event, and how is it calculated?
The odds of an event is the ratio of the probability of an occurrence compared to the probability of a non-occurrence
What is meant by odds ratio and how is it calculated?
P(exposed)/[1-P(exposed)] / P(unexposed)/[1-P(unexposed)]
What is meant by epidemiology?
The study of frequency, distribution and determinants of disease and health related states in populations in order to prevent and control disease
Define incidence rate
[Number of people who have become cases in a given time period] / [total person-time at risk during that period]
What is the denominator of incidence rate?
Person-time
What is meant by person time?
The measure of time at risk, i.e. time from entry to a study to:
1) disease onset
2) loss to follow-up
3) end of study
What is meant by attributable risk, and how is it calculated?
Rate of disease in exposed that may be attributed to the exposure
Attributable risk = incidence in exposed - incidence in unexposed
What is meant by relative risk, and how is it calculated?
Ratio of risk of disease in the exposed to the risk in the unexposed
Relative risk = incidence in exposed / incidence in unexposed
What is relative risk reduction, and how is it calculated?
Reduction in rate of outcome in intervention group relative to control group
[Incidence in unexposed - incidence in exposed] / incidence in unexposed
What is the absolute risk reduction?
Absolute difference in rate of events between 2 groups
Incidence in unexposed - incidence in unexposed
What is meant by NNT? How is it calculated?
Number of patients that need to be treated to prevent one bad outcome
NNT = 1/absolute risk reduction
(i.e. risk in unexposed - risk in exposed)
What are the 5 factors that could be responsible if a study finds an association between an exposure and an outcome?
Bias Chance Confounding Reverse causation True causation
Define bias
Systematic deviation from the true estimation of the association between an exposure and an outcome
What are the 3 main types of bias?
Selection (eg non-response, loss of follow up)
Information (eg measurement)
Publication (eg negative results may be less likely to be published)
What are some potential sources of information/measurement bias?
Observer
Participant (recall, reporting)
Instrument (calibration)
What is meant by confounding?
A situation in which the estimate of association between an exposure and outcome is distorted because of the association of the exposure and another factor (confounder) that is also indepenently associated with the outcome
What are the Bradford-Hill criteria for causality?
Strength of association Dose-response Reversibility Biological plausibility Consistency Temporality Analogy etc
What are the 3 main types of health behaviours?
Health (prevent disease, eg healthy eating)
Illness (seeking remedy, eg going to Dr)
Sick role (getting well, eg taking meds)
What is the theory of planned behaviour?
What are the 3 factors that determine intention in the theory of planned behaviour?
Proposes that the best predictor of behaviour is INTENTION ie “I intend to give up smoking”
Attitude (think smoking is bad)
Subjective norms (people want me to stop smoking)
Perceived behavioural control (i CAN give up smoking)
What are some criticisms of the theory of planned behaviour?
Does not take into account emotions
Relies on self-reported behaviour
Lack of temporal element
Assumes that attitudes, subjective norms and perceived behavioural control can be measured
What are the 6 stages of the stages of chance model?
Pre-contemplation Contemplation Preparation Action Maintenance Relapse
What are 3 advantages of the stages of change model?
Acknowledges individual stages of readiness
Accounts for relapse
Gives an idea of time-frame/progression
Give a disadvantage of the stages of change model
Does not take into account values, habits, culture, social and economic factors
Not all people move through every stage
What are the 4 factors of the health belief model?
Perceived:
- Susceptibility
- Severity
- Benefits
- Barriers
Which factor of the health belief model has been shown to be most important?
Perceived barriers
Give 3 disadvantages of the health belief model
Does not consider emotions and behaviour
Does not differentiate between first time and repeat behaviour
Cues to action are often missing
What are some examples of cues to action which may influence behaviour change
Internal (increase in pain, decrease in ADLs)
External (reminders in post, pressure from families, etc)
Give 4 factors that can be used to help people act on their intentions
Perceived control
Anticipated regret
Preparatory actions
Implementation intentions
What are 3 allocation theories?
Egalitarian (all care necessary and appropriate is provided - difficult with finite resources)
Utilitarian (maximise public utility)
Libertarian (individual is responsible for their own health)
Give 6 of the GMC duties of a doctor
1) care of patient = first concern
2) protect + promote health
3) provide good standard of practice + care
4) treat patients as individuals, respect dignity and confidentiality
5) work in partnership with patients
6) be honest, open and act with integrity
What is meant by primary, secondary and tertiary intention with respect to wound healing?
Primary: little/no tissue loss, wound edges directly opposed
Secondary: wound edges not opposed, granulation and epithelialisation occurs
Tertiary: wound purposefully left open (eg debridement needed) - surgically closed later
Give 3 patient factors that act as a barrier to healing
Elderly Diabetes Malnutrition Malignancy Renal/hepatic failure Drugs Immunosuppression Vitamin deficiencies
5 main types of wound dressing?
Hydrogel Alginate Hydrocolloid Foams Non-adherent dressings
What tool can be used to assess domestic abuse?
DASH tool (domestic abuse and sexual harassment tool)
What do you do if you believe someone is HIGH risk for domestic abuse?
Refer to MARAC/IDVAS where possible (with consent)
Can break confidentiality if consent not obtained
What is the definition of an evaluation of health services?
Assessment of whether a service achieves its objectives
What are the 3 elements of the Donabedian framework for a health service evaluation?
Structure (buildings, staff, equipment)
Process (what is done, e.g. no patients seen in A+E)
Outcome (morbidity, mortality, QALYs, PROMs, patient satisfaction) - or 5 Ds - death, disease, disability, discomfort, dissatisfaction
