Module 2 Flashcards
What does the causes of the causes mean?
The determinants of the determinants - E.g what causes people to smoke
What are some examples of the determinants of the determinants?
- These can be stress, debt, alcohol, labour intensive jobs etc
What are the causes of the causes for individuals?
“Any event, characteristic, or other definable entity, that brings about a change for the better or worse”
E.g Income, employment, education, housing & neighbourhoods, societal characteristics, autonomy & empowerment - social cohesion
These determinants may vary at different life-stages
What are the cause of causes/determinants for populations?
Concepts similar as for individuals, but nature of determinants if 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
Frame of Dahlgren & Whitehead model?
Individual lifestyle factors
Social & community networks
Living and working conditions
General socioeconomic, cultural, & environmental conditions
Public health frame work?
Provides Max benefit for largest number of people, & reduce inequities in the distribution of health and well-being
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, political, social, physical and built environments
Upstream determinants
Social capital?
The value of social networks that facilitates bonds between similar groups of people
Habitus
Lifestyle, values, dispositions and expectation of a particular social groups learned through everyday activities
The four capitals?
Financial/planning capital Social capital Nature capital Human capital All interlinked
Well-being relies on ?
Growth, distribution & sustainability of the 4 capitals
Structure determinants?
Upstream
Social & physical environmental conditions/ patterns that influence choices and opportunities available
Agency determinants?
The capacity of a individual to act independently & make free choices
Empowerment
Individual vs population health care?
Clinicians - generally deal with individuals - Aim to treat disease
Population - is concerned with the health of groups of individuals
Why is pop health so important?
25 yrs of life expectancy attributed to pop health
Bradford and hill framework ?
Aid to thought
Don’t need to fulfill all aspects
Bradford and hill framework aspects?
Temporality Strength of association Consistency of association Biological gradient Reversibility Specificity Biological plausibility
Rationale for Maori Health promotions ?
Maori health status/ inequalities
Rights as indie genius peoples & treaty partners
Mainstream health promotion interventions have generally been less effective for Maori then for non Maori
Causes of health inequalities?
Unequal distribution of health risks and opportunities
Models for Maori Health ?
The Ottawa Charter
Te Pae Mahutonga
The Ottawa charter ?
Tries to guide action toward health promotion
Key principles:
- Build public health policy
- Create supportive environments
- Strengthen community action
- Develop personal skills
- Reorient health services
Te Pa Mahutonga - A Maori model of health promotion
- 4 key tasks
Mauriora
Waiora
Toiora
Te Oranga
- 2 Pointers
Nga Manukura
Te Mana Whakahaere
Mauiora?
Access to Te Ao Maori - access to community, language, Marai, etc
Waiora?
Environmental protection - waterways but also racism, protecting health
Toiora?
Healthy lifestyles - Good health, exercise, alcohol, smoking, safe sex etc
Te Oranga
Participation in society - determinants eg housing, income , education to live a good life
The 2 pointers
NGA Manukura - Leadership - health professionals and community leadership
Te Mana Whakahaere - Autonomy - capacity for self governance, community control & enabling political environment
Te mana whakahaere
Autonomy
Nga Manukura?
Leadership
Preventative action can be put in place before the cause is identified?
Tuberculosis
Does epidemiology determine the cause in an individual?
No epidemiology DOES NOT determine the cause of a disease in an individual
Epidemiology relies on a lot of observational studies? Yes or no?
Yes
Aspects of the Bradford and Hill model include?
Temporality Strength of association Consistency of association Biological gradient (dose response) Biological plausibility of association Specificity of association Reversibility
Temporality?
First the cause then the disease
Essential to establish a causal relationship
Strength of association ?
The stringer the association the more likely to be causal in absence of known biases
Consistency of association ?
Replication of the findings by different investigators at different times, in different places, with different methods
Biological gradient ?
Incremental change in disease rates in conjunction with corresponding changes in exposure
Biological plausibility?
Does the association make sense biologically? Don’t need biological proof
Specificity of association?
A cause leads to a single effect or an effect has a single cause. However, health issues have multiple, interacting causes & many outcomes share causes
Reversibility ?
The demonstration that under controlled conditions changing the exposure causes a change in the outcome
We apply the Bradford hill Criteria & Rothmans causal pie to what?
To Identify the determinants of disease
- can also use temporality, strength of association & consistency of association to study causality
Necessary cause in the causal pie?
A factor or component that must be present if a specific disease is to occur
Component cause ?
Each factor or slice is a component
A factor that contributes towards disease causation, but is not sufficient to cause disease on its own
They interact to produce disease
Sufficient cause?
The whole pie
A minimum set of conditions without anyone of which the disease would not occur
Natural capital?
Refers to all aspects of the natural environment needed to support life and human activity
Human capital?
Encompasses peoples skills, knowledge, physical and mental health - these are things that allow individuals to participate fully In work, study, recreation, and society
Financial capital?
Things which make up the countries physical and financial assets which have a direct role in supporting incomes and material living conditions such as factories, hospitals, buildings
Types of healthcare services?
Primary - Patients regular source of healthcare
Secondary - specialist care (neurologist)
Tertiary - hospital based care/ rehab
Health promotion?
Acts on determinants of well being
Health/ wellbeing focus
Empower people to increase control over and improve their health
High risk individual strategy’s?
Advantages v disadvantages
Advantages:
- appropriate to individuals
- subject and physician motivation
- cost effective use of limited resources
- favourable benefit to risk ratio
Disadvantages:
- cost of screening/ need to identify individuals
- temporary effect
- limited potential
- behaviourally inappropriate
Pop based (mass) strategy?
Advantages:
- radical addresses underlying cause
- large potential
- behaviourally appropriate
Disadvantages:
- small benefits to individuals
- poor motivation for individuals and physician
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?
Focuses on whole pop
Aims to reduce health risks/ improve outcome of all individuals in pop
Useful for a common disease or widespread cause
Type of pop health actions?
Health promotion
Disease prevention
Health protection
Why is the 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 escalates
Intervening disease?
Use association and other factors too infer causation and intervene to prevent disease.
Can intervene at any number of points in the pie
Causal pie - identifying components?
Don’t need to identify every component cause to prevent same cases of disease
Knowledge of the disease is not a prerequisite for introducing preventative measures
Causal pie - blocking/removing component causes?
Blocking/ removing any component cause would result in prevention of some cases of disease
Causal pie - environment
Every causal mechanism always has some environmental component cause(s)
What is a ‘cause disease’?
An event, condition and or characteristic which play an essential role in producing the disease
Most epidemiological studies are?
Non-experimental and conducted in noisy environments in free living populations.
Why establish a causal relationship?
Provide support for evidence based practice
Importance of preventing disease?
- Unravelling the causal pathway
- Directing preventive action
- Evaluation of effectiveness
High risk strategy advantages?
Address individual problems
Individual & physician motivation
Favourable benefit-to-risk ratio
High risk disadvantage?
Cost of screening - need to identify individual first
Temporal effect
Limited potential
Behaviourally inappropriate
Pop based mass strategy ?
Radical- address underlying causes
Large potential benefit for the whole pop
Behaviourally appropriate
Pop based mass strategy ?
Small advantages for individuals
Physician unmotivated
Individual unmotivated
Whole pop exposed to downside of strategy
Alma ata 1978?
Declaration for primary health care
- protect and promote health of all
- advocated a health promotion approach to primary care
Alma ata 1978 prerequisites for health?
Peace and safety from violence Shelter Education Food Income and economic support Stable ecosystem and sustainable resources Social justice and equity
The Ottawa charter for health? Acknowledges?
That health is:
- A fundamental right
- Require both individual and collective responsibility
- Opportunity to have good health should be equally available
- Good health is an essential element of social & economic development
3 basic strategies of Ottawa charter?
- Enable
- Advocate
- Mediate
Enable? Ottawa charter
To provide opportunities for all individuals to make healthy choices through access to information, life skills and supportive environment
Advocate? Ottawa charter
To create favourable political, economic, social, cultural & physical environments by promoting/ advocating for health and focusing on achieving equity in health
Mediate? Ottawa charter
To facilitate / bring together individuals, groups & parties with opposing interest to work together/ come to a compromise for the promotion of health
Health protection?
- predominantly environment hazard focused
- risk hazard assessment
1. Environmental epidemiology
2. Safe air & water, bio security
Occupational health and monitoring
Screening in health ?
Screening involves identifying risk factors, or unrecognised disease or complication of a disease by applying tests on-a large scale to a population
Screening as a preventive strategy?
Primary
Secondary
Tertiary
Screening programs can be what?
Can be primary, secondary or tertiary depending on what your screening
Screening criteria?
Suitable disease, test, treatment, screening
Objective screening initiative ?
To improve health outcome (morbidity, mortality, disability)
Suitable disease?
- An important public health problem
- relatively common
- relatively uncommon(sometimes) - Knowledge of the natural history of the disease (or relationship of risk factors to the condition)
- detection early
- increased duration of pre-clinical phase
Suitable test?
Reliable Safe Simple Affordable Acceptable Accuracy (specificity, sensitivity)
Sensitivity?
The likelihood of a positive test in those with the disease
True positives/ all with the disease (x100)
Specificity ?
The likelihood of a negative test in those without the disease
- the ability of the text to identify correctly those who do not have the disease from all individuals free from the disease
True negatives/ all without disease (x100)
Diagnostic test accuracy studies?
- The sensitivity of a screening test is high if the proportion of the true positives is high
- The specificity is high if the proportion of true negatives is high
Are sensitivity and specificity fixed character of the test?
Yes - that’s how accurate the test is when tested against the gold standard
Accuracy of a screening test in practice?
Done by PPV and NPV
What is positive predictive test?
The proportion who really have the disease out of all people who tested positive
The probability of having the disease if the test is positive
True positives/ all who test positive (x100)
Negative predictive Value?
- The proportion of people who really don’t have the disease out of everyone who test negative
- The probability of not having the disease if the test is negative
True negatives/ all who tested negative (x100)
Suitable treatment?
Evidence of early treatment leading to better outcomes
Effective, accessible and acceptable treatment
Suitable screening programme?
- benefits must outweigh harm
- RCT evidence screening programme will result:
Reduced mortality
Increased survival time - leads to 1. Lead time bias, Length time bias - cost effective
- healthcare system must be able to support all elements of the screening pathway
Lead time bias in suitable screening programme?
Patients may die at the same stage - but early detection may give you the impression your living longer
Length time bias in suitable screening programme?
Screening identifies 2 patients with rapidly progressive disease & 5 patients with slowly progressive disease
- calculating mean survival from screened patients gives an impression of longer average survival than occurs in the pop
Breast screening ?
Suitable disease
Suitable test - screening mammogram
Suitable treatment - surgical and other treatment
Suitable program - BreastScreen Aotearoa
PPV and NPV are they fixed?
No they are not - they are dependent on test accuracy and prevalence
Why do we need to prioritise in health?
Because there is currently not enough money in the kitty to fund all the health problems we would like
How well the money is spent normally replicates into longer health expectancies
LE?
Life expectancy at birth
Where does the NZ dollar go to?
- Health & administration
- Prevention & public health services
- medical goods dispensed to outpatients
- Ancillary (ambo etc) to health care
- services of long term nursing care
- Services of curative & rehab care
What are the 3 main population health priorities ?
Evidence based measures
Community expectations & values
Human rights and social justice
Evidence based measures can be broken into?
Descriptive
Evaluative
Explanatory
Descriptive evidence based measures?
Who is most/ least effected?
Where are they now?
What are the trends over time?
Where are they going?
Explanatory evidence ?
What are the determinants? What are the risks?
Why are we getting worse/better?
Why are populations different?
Population Attributable risk (PAR) Risk difference (AR) - risk difference
Equity?
Does the problem/risk factor disproportionately affect population subgroups? Why?
Treaty of waitangi
Population attributable risk (PAR)?
- The amount of “extra” disease attributable to a particular risk factor in a Particular population
Calculating PAR?
PGO (occurrence in total population) - CGO (occurrence in unexposed population)
Risk difference (RD) = Attributable risk (AR)
EGO - CGO
The amount of “extra” disease attributable to a particular risk factor in the exposed group.
- incidence in exposed population (EGO)
Evaluative evidence?
- What can improve health outcomes (and in whom)?
- Is the intervention improving health outcomes?
How well can the problem be solved?
- Target population
- Expected number in population who will be reached
- cost
What is economic feasibility in in evaluative?
Does it make economic sense to address the problem? Are there economic consequences if not carried out ?
Is it important to be mindful of the community expectations when establishing population health priorities?
Yes it It critical to be mindful
Community acceptability?
Will the Community and/or target population accept the problem being addressed?
What do the community want?
- confidence in the health system
- access to necessary care
- Fair treatment
- culturally appropriate
- Good information about their options
The 4 steps in the public health frame work?
- Define the problem
- Identify the risk & protective factors
- Develop and test preventive strategies
- Assure widespread adoption
Predictive value:
If the prevalence is high ?
Higher false negatives
Predictive value:
If the prevalence is moderate to low ?
Higher false positives
What does PAR mean?
It’s the amount of extra disease attributable to a particular risk factor in a certain population
It’s the amount of disease we can prevent if we remove the risk factor from the population
