Module 2: Deciding on Interventions to Improve PopHlth Flashcards
Frame of Dahlgren and Whitehead (Rainbow) model
Triangle - Population
Rainbow - Understanding effects of SEP and other determinants
Rectangle - Identifying inequalities and inequities and why/how they should be reduced
Time arrows
PHF (public health framework)
Provides max benefit for largest number of people, and reduce inequities in the distribution of health and well-being
Define problem - cross-sectional studies
Identify risk and protective factors - cohort studies, case-controlled studies
Develop and test prevention strategies - RCTs, diagnostic test accuracy studies
Assure widespread adoption - evaluative studies
Causes of causes/determinants - for individuals
Any event, characteristic, or other definable entity, that brings about a change for better or worse in health
May vary at different life stages
Income, employment, education, housing and neighbour hoods, societal characteristics, autonomy, empowerment - social cohesion
Causes of causes/determinants - for populations
Concepts similar as for individuals, but nature of determinants is often different
Related to the context in which the pop exists - different populations exert different characteristics
Downstream vs upstream interventions
Downstream: operate at the micro (proximal) level
e.g. treatment systems, disease measurement
Upstream: operate at the macro (distal) level
e.g. government policies, international trade agreements
Proximal determinants
A determinant of health (downstream) that is proximate/near to the change in health status
Directly associated
e.g. lifestyle, nutrition
Distal determinants
A determinant of health (upstream) that is distant in time and/or place from change in health status
e.g. national, political, cultural factors
3 levels of influence
Level 1: The person
Age, sex, biology, behaviour risk factors, lifestyle
Downstream determinants
Level 2: The community
Local influences, e.g. home, workplace, neighbourhood
Social capital
Wider societal levels, e.g. education and healthcare system
Downstream determinants
Level 3: The environment
Cultural, social, political, physical and built environments
Upstream determinants
Social capital
The value of social networks that facilitates bonds between similar groups of people
Habitus
Learning behaviours by being exposed to the group in which you’re in
4 capitals
Natural, human, societal, financial/physical
All interlinked
Well-being outcomes - individuals
Better physical and mental health
Education outcomes
Labour market outcomes
Housing outcomes
Well-being outcomes - societal
Stronger economic performance
Better democratic functioning, safer communities
More inclusive societies
Structure determinants
Upstream
Social and physical environmental conditions that influence choices and opportunities available
Agency determinants
The capacity of an individual to act independently and make free choices
Empowerment
Individual health care - clinicians
Aim to treat disease - to restore health
Reactive form of treatment
Only interested in people who present to the healthcare
Find cause of symptoms in individual patients
Population healthcare
Concerned with health of groups of individuals, in the context of their environment
Identify and treat all appropriate patients in a population - population approach to clinical practice
Also interested in those who have the disease but don’t know they have it, and those who don’t have the disease (why don’t they have it?)
Social and physical environment of population
Important role of epidemiology
Seek cause of dis-ease
Why establish causal relationships?
Provide support for evidence-based practice
Epidemiology doesn’t determine the cause of a disease in a given individual, instead…
It determines the relationship between a given exposure and dis-ease outcome in populations
Most epidemiological studies are…
Non-experimental and conducted in ‘noisy’ environments in free-living populations, therefore establishing causal interferences should be done cautiously
Causes of low-life expectancy within an impoverished community
High prevalence of health-endangering behaviour (individual level)
Poor education, lack of healthcare (population level)
Cultural disintegration, poverty (societal level)
Why can’t causality be proven in human studies
Practical and ethical reasons
Bradford Hill criteria
Helps establish causality
‘Aid for thought’ - just a guideline, not a checklist
Temporality:
- cause comes before disease
- essential to establish a causal relation
- generally easier to establish from cohort studies
Strength of association:
- measured by size of relative risk
- the stronger the association, the more likely to be causal in absence of known biases
- RR > 2: moderate strong association
- RR > 5: strong association
Consistency of association:
- replication of findings by diff investigators, at diff times, in diff places with diff methods, i.e. multiple studies show similar results –> more likely to be causal
- however, lack of consistency doesn’t exclude a causal association since diff conditions may reduce impact of causal factor in certain studies
Biological gradient (dose-response):
- incremental change in disease rates in conjunction with corresponding changes in exposure
Biological plausibility of association:
- does association make sense biologically?
Specificity of association:
- a cause leads to a single effect or an effect has a single cause
- however, health issues have multiple, interacting causes, and many outcomes share causes
Reversibility:
- the demonstration that under controlled conditions, changing the exposure causes a change in outcome
- ideally assessed by RCT but often not possible
Causal phenomena - complexity
Causal phenomena are usually complex - and exposure - outcome relationships usually not 1:1
Causality is multi-factored
What is a ‘cause of disease’
An event, condition and/or characteristic which play an essential role in producing the disease
Causal pie - components
Sufficient cause (causal mechanism):
- the whole pie
- a minimum set of conditions without any one of which the disease wouldn’t occur
- not usually a single factor; often several
- a disease may have several sufficient causes
Component cause:
- a factor that contributes towards dis-ease causation, but is not sufficient to cause dis-ease on its own
Necessary cause:
- a factor/component cause that must be present if a specific dis-ease is to occur
Causal pie - environment
Every causal mechanism always has some environmental component cause(s)
Causal pie - blocking/removing component causes
Blocking/removing any component cause would result in prevention of some cases of disease
Causal pie - identifying components
Don’t need to identify every component cause to prevent some cases of disease
Knowledge of the complete pathway is not a pre-requisite for introducing preventative measures
Intervening disease
Use association and other factors to infer causation and intervene to prevent disease
Can intervene at any number of points in the pie
Why is need for prevention of disease growing
The need for prevention is growing as the limitations in curing disease become apparent and as the costs of medical care escalate
Types of pop health actions
Health promotion
Disease prevention
Health protection
All of which are split into population based (mass) strategies or high risk (individual) strategies
Population based (mass) strategy
Focuses on whole pop
Aims to reduce health risks/improve outcome of all individuals in pop
Useful for a common disease or widespread cause
High risk (individual) strategy
Focuses on individuals perceived to be a high risk
Intervention is well matched to individuals and their concerns
e.g. NZ needle exchange program –> helps prevent spread of HIV
Pop-based (mass) strategy - advantages and disadvantages
Radical - addresses underlying causes
Large potential benefit for whole pop
Behaviourally appropriate
Small benefit to individuals
Poor motivation of individuals
Whole pop is exposed to downside of strategy (less favourable benefit - risk ratio)
High-risk (individual) strategy - advantages and disadvantages
Appropriate to individuals
Individual (subject and physician) motivation
Cost-effective use of rss
Favourable benefit : risk ratio
Cost of screening; need to identify individuals
Temporary effect
Limited potential
Behaviourally inappropriate
Health promotion
Acts on determinants of well-being Health / well-being focus Empowers people to increase control over and improve their health Involves whole pop in every day contexts Pre-disease
Types of healthcare services
Primary - patient’s regular source of healthcare
Secondary - Specialist care
Tertiary - hospital based care, rehabilitation
Alma Ata 1978: Declaration for primary healthcare
Protect and promote health of all
Advocated a health promotion approach to primary care
1st time social determinants in health was recognised as key to achieving good health in populations
Pre-req for health:
- peace and safety from violence
- shelter
- education
- food
- income and economic support
- stable ecosystem and sustainable rss
- social justice and equity
Ottawa Charter for health promotion (WHO) 1986
‘Mobilise action for community development’
First time human rights was brought to health
Charter acknowledges that health is:
- a fundamental right for everyone
- requires both individual and collective responsibility
- opportunity to have good health should be equally available
- good health is an essential element of social and economic development
Ottawa Charter 1986 - 3 basic strategies
Enable - provide opportunities for all individuals to make health choices through access to info, life skills, and supportive environments (individual level strategy)
Advocate - create favourable political, economic, social, cultural and physical environments by advocating for health and focusing on achieving equity in health (system level strategy)
Mediate - bring together individuals, groups, and parties with opposing interests to work together and come to a compromise for promotion of health (strategy that joins up individuals, groups and systems)