Disease causation and the diagnostic process in relation to public health, prevention and health promotion. Flashcards
Issues that complicate early years intervention evaluation
- Study designs: Ethics of RCTs on preventative interventions, evaluating national interventions such as fortification of flour to improve pregnancy outcomes.
- Lack of control group/ poorly designed studies over time
- Difficult to measure absence: impossible to project over 20 years what disease prevalence/crime rates might be, how to show the absence of that?
- Lead times: Early years has long term follow up, studies are costly and complex to F/U over this time frame. E.G childhood education to reduce smoking and lifetime risk of lunch ca.
Five key areas of early years evidence
Eduction, Nutrition, Socio-economic benefits, Emotional and social supply, Combined programmes.
Education programmes in early years
Pre school education and parenting education.
Pre school:
Sylvia et al 2004. Cohort study, 3000 children across Europe.
Pre school attenders had higher educational and social attainment.
Quality of schooling did affect attainment
Socioeconomic status did not affect benefit gained by preschool
What parents did with children had more affect than SE status, e.g reading.
Health and nutrition in early years
LBW- increases risk of chronic conditions. Evidence suggests maternal nutrition affected weight, Ca and folate supplements have shown positive outcomes. (Healthy start scheme) Smoking doubles risk of LBW.
Breastfeeding- increased passive immunity, lower SIDs, Reduced obesity, diabetes and atopy, greater bonding, reduced risk of breast and ov cancer in mothers.
Childhood immunisations
Interventions to reduce injuries e.g cycle helmets.
East Sussex childhood injuries picture
- ES 67% of admission due to accidents in under 5s happened within a home.
- High rates in ES compared to England. Particularly bad in deprived areas of Hastings and Rother.
- Higher rates of falls, and accidental poisonings.
- East Sussex fire and rescue service offers home visits for safety checks, education and fitting of safety equipment
Socio- economic benefits in early years
Acheson Report
Families with young children are at increased risk of poverty:
Need affordable childcare
Increase benefits and availability of benefits for pregnant women and families with young children.
Emotional/social support in early years
Evidence for community family support programmes.
Aim to improve parent wellbeing, and children physical, emotional and cognitive development.
European Early Promotion project (2005) found healthcare worker training to support parent infant relationships led to fewer psychological problems in children.
Combined programmes in early years
Programmes that combine multiple aspects.
Sure start (UK)/ Head start (USA)
Pre determinants of health
Factors that indicate/contribute to determinants of health.
Material: Food and water, clean air, Income, housing, Green spaces.
Policy: Minimum wage, Occupational health, Maternal services, Childcare, Benefits and education.
Society: Social cohesion, values and attitudes, ethnic diversity and tolerance, language ability.
Social cohesion
Pre determinant of health.
Society with strong social cohesion- strong interactions, supportive, few inequalities.
Wilkinson (1996) reduced income differentials, greater solidarity, and social cohesion lead to improvements in life expectancy.
Can influence and be influenced by health policy. E.g private insurance could increase inequality.
Motivational interviewing
Motivational interviewing: Rollnick and Miller (1990s) counselling based on the stages of change model. Explores models about why an individual may be ambivalent about behaviour change.
Evidence in drug misuse, smoking cessation, eating disorders.
It utilities: empathy, highlight discrepancies, roll with resistance (respond with understanding not confrontation), build self efficacy.
Individual behaviour change techniques
Motivational interviewing, CBT, incentives
Incentives
Marteau et al 2009
vouchers to encourage smoking cessation, points scheme for healthy school meals (UK)
money towards healthcare costs in improve adherence (USA)
Financial rewards to avoid STIs (Tanzania)
Financial rewards for achieving weight loss targets (Italy)
Incentives- pros and cons
+ effective in short term
+ potential effective long term combines with other activities
- Moral concerns- bribery
- overall paternalistic
poor use of public funds
Define social marketing
Use of techniques of commercial marketing ti sell a health message
Approach to social marketing
- Identify target group: segmentation tactics (define group by lifestyle choice rather than disease state)
- Research target group: survey and focus groups. Assess attitudes, habits, needs.
- Competitive analysis: competition is anything that may encourage the unhealthy behaviour e.g tobacco marketing
- Set objectives
- Develop a message: pretest with target group
- Sell the message
- Evaluate
Four Ps of marketing
Product : It must be clear what is being sold.
Price: financial na opportunity costs
Place: channel used affects exposure to certain groups
Promotion: medial and advertising, e.g TV, Magazine, partnership with companies.
Strengths and weakness of social marketing
+ Based on understanding of the target group
+ Clear objectives
+ Uses successful commercial techniques
- Assumes behaviour is individual choice
- Danger of portraying partial message e.g “Just say no” catchier than well rounded pos/neg of drugs
- Can reinforce same stereotypes as commercial marketing e.g health = positive physical attributes or = positive moral attributes
Reasons for public involvement
- Improved concordance
- Empowerment
- Democracy
- Acceptability
- Ownership and sustainability
- Integrated approaches: More complex issues are tackled with community members insights as a problem solving tool.
- Better decisions
Absolute vs relative poverty
Absolute: Lacks basic material needs
Relative: lives under 60% of median national income
Factors that reinforce the effects of deprivation
Social exclusion, discrimination, employment, stress, antenatal effects.
Local strategic partnerships
Statutory multi agency bodies
Functioned in areas of LA
Encourage collaborative working and community involvement
Statutory, voluntary, community and private sectors
Why do we set targets in healthcare?
Adaptation of management practices and culture
Improvement of performance and accountability
Consistency
Levels of target setting
Individual e.g personal PDP
Organisational e.g LA target for provision of affordable housing
National e.g Public Service Agreement- Given set minimum target for sectors in return offer investment, schools/health etc
International: WHO’s SDGs, Health for All targets
Criteria for good targets
Specific
Measurable
Achievable
Relevant
Timely
Pros and Cons of targets
+ Provide a focus for performance improvement
+ Explicit priority setting - provides common agenda for a team.
+ Provide accountability
+ Level playing field for organisations under comparison
+ Targets reflect organisations priorities and goals
+ Share good practice
+ Increase interest in particular areas
- Might not be measurable (particularly in health), such may take focus away from some health areas
- Gaming (distortions of practice). e.g reclassifying trolleys in ED as beds to meet 4h targets.
- Distort priorities. Areas where targets are not easily set may be neglected
- Disengagement from staff when targets set top down.
- Costs
Things to consider when setting targets
Closely correlate to clinical outcomes
Select with consensus from team- evidenced, feasibly, acceptable
multiple time frames
Consider which priorities we want the public to know are important/ form of education public on important targets
Targets are practical expression of guidelines
Donabedian’s Framework
(2005)
Framework to evaluate health programmes.
Structure/input, process and outcome measures/targets applied to each to evaluate programmes.
Programming approach
Epidemiological paradigm
Long term effects of environmental exposures during critical periods.
E.g Barker Hypothesis- in utero malnutrition as a risk factor for CHD
Adult risk factor approach
Epidemiological paradigm
Impact of lifestyle and behaviours
Life course approach
Epidemiological paradigm
Combines elements if programming and adult risk factor approach.
Various risk factors across gestation and life affect health and disease.
Limitation:
Little research on very longitudinal cohorts.
Screening: Definition
Aim: Identify people who can be helped in the early stage of disease.
“identify apparently healthy people in the early stages of disease/increased risk. Such that they can be offered information, or further tests and treatment.”
NSC: National Screening Committee
UK Screening programmes
Antenatal:
Early- HIV, Syphilis, hepatitis B, Rubella, Haemolytic diseases, Sickle cell, thalassaemia.
Mid- Downs, Fatal abnormalities.
Neonatal:
Heel prick- PKU, Congenital hypothyroid, sickle cell and thalassaemia, CF, MCADD
Hearing screening
Heart defect, cataract, Malformations, cryptorchidism, hip dislocation.
Childhood:
Growth- turners, growth hormone deficiency
Hearing
Vision
Adult:
AAA- one off USS at 65.
Breast ca- 3 yearly mammogram 50-71
Cervical ca - HPV test, 25-49, 3 yearly
Bowel ca- Feacal occult blood, 60-69, 2 yearly.
DM retinopathy- 12 year + with DM, annually.
Non screening secondary prevention programmes
Health checks
Childhood obesity
Chlamydia
Prostate ca
TB
Reasons for setting high sensitivity for screening tests
Significant disease with definitive treatment
Rick of infectivity to others
Subsequent test cheap/low risk
Reasons for setting high specificity for screening tests
Unpalatable treatment
Costly/ high risk subsequent test
ROC curves
Receiver operated characteristic curves
Plots the trade off between sensitivity and specificity (TP/FP)
- Aids threshold setting for tests
- Helps compare different possible screening tests
Should be high and left
Active case finding
Systematically searching for high risk people. E.g GP identification of high risk CHD, Genetic testing of family, case finding in disease outbreaks.
+ Cheap
+ Low personal demand
+ Improves PPV of a test
+ Targets prevention
+ Cost effective for familial conditions
- Potential to widen inequalities for hard to reach groups
Likelihood ratios
How many more times people with the disease are likely to have a positive test result
LR > 1 test result is associated with presence of disease. > 10 high likelihood
LR < 1 Result indicates absence of disease
The further from one indicates stronger association.
Positive LR = Sensitivity/ (1- specificity)
Pre test probability
“the probability of the screened person having the disease”
= prevalence
Pre test odds = Pre-test probability/ [1 – Pre-test probability]
Using routine data, practice data, and clinical judgement
Post test probability
“is the probability of the patient having a disease after obtaining the test results”
Can be extrapolated from PPV - but this is based on prevalence
Can also be estimated from pre test probability and LR - (using Bayesian statistics)
Fagans nomogram can be used.
Factors that affect screening participation
+ Perception of severity
+ Perception of susceptibility
+ Perception of benefit
+ Knowledge of disease
+ Knowledge of treatment
- Phobia
- Disease severity (low)
- High residential mobility
- Low acceptance of test
- Stigma
- Inaccessibility
Informed choice in screening
GMC
Patients need to know
- Purpose of the test
- Risks of test
- Likelihood of positive findings
- Possibility of false results
- Implications of screening
- Follow up
Screening : Evaluation
- Relative burden of disease
- Feasibility
Organising attendance, acceptability, post screen care, costs - Effectiveness
- Extent to which the programme affects outcomes
- Consider bias (selection, lead time, length time)
- Issues with understanding over diagnosis, takes time/ long follow up.
Screening : Planning
Consider:
Who is eligible
How often to screen
Invitations
Quality assurance
Wilson and Jungner criteria-
Disease is :
Important, pre clinical stage/natural history known. latent period.
Test is:
Valid, simple/cheap, acceptable, reliable
Follow up:
Agreed policy in place, facilities to diagnose/treat, Treatment available
Overall:
Evidenced, Acceptable, Opportunity cost balanced, adequate staffing/facilities, Clear management, patient able to make an informed choice.
Screening : Case study’s (bowel, breast, prostate)
Bowel ca- England uptake 69.6% 21/22
Less in deprived areas compared to affluent areas.
Breast ca- DH and Ca research review found that for 10 000 screen cases 43 deaths prevented, 129 over diagnosed. Suggested new information should be given to reflect this.
Prostate ca- Not recommended. Test low sens/spec, unclear which treatment option is the best.
Cervical cancer
England uptake- 69%
Control of genetic disease
testing of embryos
Ante/neonatal testing
Screening for genetic conditions
Treatment to reduce risk (familial hypercholesterialaemia)
Genetic counselling
National nutrition surveillance
Food supply data- imports/exports, agricultural data, food mapping exercises.
ONS Living cost and food survey- annual, self reported diaries, 5,000 homes across the UK.
Diet and nutrition surveys- (Self reported, biased and unreliable ) DH and food standards agency: National diet and nutrition survey. 1000 adults.
Breast feeding survey, every 5 years
School meals - from LA catering services.
Self reported surveys- children,
Nutritional interventions
Flouridation of water
Fortification of food- folic acid in flour.
School and workplace campaign- canteen meals
TV
Collaboration with food industry
Free fruit in schools
Sugar tax
Social determinants of diet
Poverty
Ethnicity/culture
- BAME- Higher fruit and veg, less fat, higher salt intake
Education
Dietary reference values
Used by professionals
Values set by healthy people in different age brackets
Estimated average requirement
Reference nutrient intake - amount needed by 97%
Lower reference nutrient intake - amount needed by 2.5%
Safe intake
Challenges in evidence for nutrition
Hard to obtain undisputed evidence
Ensuring risks are accepted
Implementing evidence to change consumption
Long term outcomes of CHD hard to research
Ethical issues of RCTs
Seven countries study- shows a link between animal fats and CHD, compared to med diets
Environmental determinants of health
Global warming/climate change
Sustainable development
Housing
Built environment
Transport
occupation
Water and sanitation
Agriculture and food
Air quality
Temperature, noise, radiation
Chemical agents
Biological agents
Environmental injustice
Exposure to environmental risk factors is greater amount more deprived people, but wealthier people are responsible for more pollution.
E.g
Weather people won care- pollute- affects people living in urban areas/poor housing
global carbon dioxide is produced by weather countries but effects of climate change felt most in developing areas
Environmental risk vs hazard
Hazard- potential to harm health (pollution, radiation, extreme temps)
Risk- probability of an unfavourable event occurring x consequences of that event
Effects of climate change on health
Direct:
Heatwaves, extreme weather
Indirect:
Changing epi of IDs
Floods- water borne disease, changing vectors
Resp diseases & pollution
Droughts- food insecurity
Rising sea levels- displacement
reduced farming activity
Pressure on resources - war
Increased skin cancer
Responding to climate change
Mitigation- reduce greenhouse gasses
Adaptation- flood defences, increased vaccine programmes, sun protection advice
Define and principles of sustainable development
Definition: “meeting our needs today without compromising the ability of those to meet their needs tomorrow”
Respecting the environment, resources, biodiversity
Health and justice- meeting needs of all communities
Governance
Evidence based - precautionary principle
Sustainable economy - Polluter pays principle
Water pollutants
Fertilisers - nitrates, phosphates
Metals- Aluminium, lead, Heavy metals
Slurry- organic waste
Sewage
Radiation
Ionising - 84% produced by naturally occurring radon gas, need to improve ventilation in homes where this occurs (due to geology). 15% healthcare <1% due to industry. Acute radiation sickness, or long term exposure e.g cancer
Non ionising- sun/ power lines/ phones. cancer, cataracts, sunburn.
Measured - Gray (GY) Energy deposited in each gram of tissue.
Single exposure of 5Gy across body- fatal
Principle air pollutants
CO
Ozone
Nitrogen dioxide (cars)/ sulphur dioxide (coal) - resp illness, acid rain
Lead-
Particulates- car emissions, resp and Cv disease
Organic compounds- traffic emissions, industrial processes- carcinogenic, smog
Radon
2 principles of EU environment legislation
Polluter pays:
Party responsible for creating pollution pays for recovery/clean up/ recycling/ disposal. Or tax on business that use non friendly products/processes
Precautionary principle:
Credible but unproved hazards should be treated as real threats. err on side of caution.
Compliance with environmental legislation
Business not aware of legislation
Monitoring variable across EU
Penalties weak
compliance not previewed as key to business survival
UK agencies involved in occupational health
Health and safety executive
Trade unions
LA
Employers
occupational health
Collectivism
That the state has a responsibility for the population.
Drink driving laws
Health and safety regulation
Fluoridation of water
Tax
Individualism
Political/moral philosophy that emphasises the individual.
Safe drinking limits advertised
Alcohol licences to allow purchase 24H a day
private healthcare providers
Policy Rainbow
Dahlgren and Whitehead 1991
Determinants exist and interconnected layers. Age, sex non modifiable but others are modifiable, and interact with health in different ways.
Used in London Health Commission report
Health Belief model
Hochbaum 1958
Person will take health related action if:
Perceived susceptible
Perceived severity
Course of action available
Benefits outweigh risks
Perceived ability to carry out action
+Useful for simple preventative behaviours
+ Evidenced to predict behaviour/improve interventions
- Complex long term behaviours (alcohol dependance) doesn’t work as well
- Doesn’t account for factors outside personal beliefs, e.g culture, provision of healthcare.
Stages of change model
Prochaska and DiClemente 1984
Behaviour change as a process. Predicts who will change behaviour and who will fail to progress through.
Pre contemplation, contemplation, determination, action, maintenance, termination.
+ Useful for complex long term behaviour changes
+ Can tailor counselling to the stages the patient is at
+ useful for programme planning to plan interventions sequentially
- Less useful for whole communities.
Spheres of health promotion
Tannahil 1985
Three overlapping spheres of activity- health education, protection against harm, prevention of disease.
+ simple
+ Widely adopted
+ encompasses wellbeing
- Difference between prevention and protection is arbitrary
Beattie Model
1991
Considers activities for health promotion and how they are delivered. Useful tool for critically evaluation of promotion programmes.
2 axis- authoritative- negotiated, individual - collective.
4 approaches - health persuasion, Personal counselling, Legislative action, Community development.
Health messages
McGuire
Source - ?credibility/trust
Message
Channel - medium and setting
Receiver - primed? targeted
destination- outcome of message
Requirements for successful communication
Be seen/heard by target
Attract attention
Be understood
Be accepted
Change behaviour
Mass communication
+simple
+many recipients
+ Useful for reinforcing ideas
+ same message reaches all
- Low flexibility
- No feedback
- Don’t know its been seen/heard
- Expensive
Individualised communication
+ Can challenge current attitudes
+ Complex messages
+ Can also use counselling techniques (support self efficacy)
+ flexible
+ feedback
- Small numbers
- Variability in dissemination of message
Community development: Activities
Formal participation, community action (priority setting), Facilitation (by health service), Interface (work closely with community), Strategy (support)
Community development: +/-
+ Projects are based in community proprieties
+ Focus on root cause of ill health
+ positive process of involvement, confidence, control
+ Can reach excluded groups
- Resource intensive
- time consuming
- hard to secure funding
- Long timescale
- results often intangible
- Conflict of accountability for community workers
Partnership working
Types: within organisation, across local areas, outreach to community
Methods: Statutory committee, Shared targets, Joint projects, Specific initiatives, joint post, shared budget
+ avoids duplication
+ Pools resources
+ Political imperatives
- Shared outcomes?
- different processes
- requires commitment
- power dynamic
- influence
Surveillance
Detects trends, Evaluate prevention/control measures, alert for threats, monitor known IDs, research
Passive, active, enhances, sentinel, syndromic.
Evaluation:
Importance of condition under surveillance
Clear case definition?
System/process - objectives, process
Analysis- methods
Usefulness
Recommendations for improvement
Evaluation of vaccine programmes
Disease surveillance
Sero-epidemiological surveillance
Market testing
Monitor adverse events
Developing and immunisation strategy: General considerations
Mass vs selective
Live vs attenuated
Age
Dose interval
Outbreak response
Surveillance
Containment
Investment in research
Developing and immunisation strategy: Mass vs selective
Mass- herd immunity. E.g Rubella
Selective - high risk groups, less costly, less adverse events e.g hep B
Outbreak investigation: concurrent tasks
Epidemiology
Control measures
Collect environmental samples
Outbreak control group
Communication
Outbreak investigation:
Epidemiology
Case definition
Confirm cases
Define background rate
Assess if outbreak has occurred
Active case finding
Time/place/ person characteristics
Epi curve
Generate hypothesis
Test hypothesis
Conclude
Outbreak investigation: Control measures
Control source, spread.
Protect at risk persons
Continue surveillance
Declare outbreak over when back to background levels
Consider future control
Outbreak investigation: outbreak control group
HP cons
Micro/ viro/toxo
Admin
Food/vets
Epidemiologist
DPH
GP
Other involved orgs - Environmental health, food standards, water standards etc
WHO disaster management cycle
Prevention
Preparedness
Detection and alert
Response
Recovery
Routine micro techniques
Microscopy, culture, id, drug sense testing
+low cost
+ definitive diagnosis
- Take time
- Low sensitivity
- can’t always isolate organism
- may not be able to provide strain with limited techniques
Reference lab techniques
Nucleic acid probes/ amplification systems
+ Incase sens/spec
+ ID orgs that don’t grow on culture
+ Genes that result in resistance
+ Epi tracking
+ New infections
+ Control of Abx resistance
- Specialist equipment
- Some techniques have longer turnaround times
