Lecture 11 + 12 Flashcards
Explain the cause of the problem.
Identifying the likely cause of the disease is in population is what epidemiology is all about.
1. Establishing causal relationships is important to provide support for evidence-based practice
2. Epidemiology does not determine the cause of a disease in an individual
3. Sometimes, preventive measures can be put in place before we determine the cause of a disease
What is the Bradford Hill Framework? (1965) “Aid to thought”.
There is a 7 points of criteria to see whether the association of the exposure and outcome is casual.
1. Temporality
2. Strength of association
3. Reversibility
4. Biological gradient (dose-response)
5. Biological plausibility of association
6. Consistency of association
7. Specificity of association
Explain the criteria for temporality, strength of association and reversibility.
Temporality = First the cause then the disease and essential to establish a causal relation.
Strength of association = The stronger an association, the more likely to be causal in absence of known biases (selection, information, and confounding). This means that if we ruled out the biases, the link between smoking and lung cancer would be more believable.
Reversibility = When the exposure / risk factor is removed, the outcome should be impacted (reduced).
Do all Bradford Hill criteria must be fulfilled to determine causality.
No
Explain biological gradient (dose response) and Biological plausibility of association.
Biological gradient = Incremental change in disease rates in conjunction
with corresponding changes in exposure. This means the more amount of exposure, the higher rate of disease outcome you will get. Think of it like a positive, linear gradient! Example: Someone smokes 1 cigarette a day → low risk of lung cancer, but someone smokes 30 cigarettes a day → high risk
Biological plausibility of association = Does the association make sense biologically?
Explain consistency of association and specificity of association.
Consistency of association = Replication of the findings by different investigators, at different
times, in different places, with different methods. Example = Multiple studies have shown similar results
Specificity of association
o A cause leads to a single effect
Many disease share causes
Smoking Lung cancer, CVD, other respiratory disease etc.
o An effect has a single cause
Disease have multiple causes
Lung cancer is caused by smoking, exposure to asbestos etc
Define epidemiological triad and what does it show.
Epidemiological triad is a framework that shows that multiple factors interact to cause a dis-ease in a population. It shows us that causal phenomena are usually complex and
exposure-outcome relationships are usually not 1:1.
Explain the epidemiological triad.
There are three main factors:
1. Host = Who gets the disease? It is smokers or non-smokers?
2. Agent = What causes the disease? It is a Biological, Nutritional,
Physical, Chemical factor?
3. Environment = What external factors allow it to happen? Physical, Social, Policy
Define cause of disease
An event, condition, characteristic (or combination
of these factors) which play an essential role in
producing the disease
Describe the sufficient cause pie from the KJ Rothman, 1986) casual pie model.
- Sufficient cause pie is the ENTIRE pie. Without any of the component that make up the sufficient pie, the disease would NOT occur. A disease may have several sufficient cause pies because several pies can produce the same disease.
Describe the component cause pie from the KJ Rothman, 1986) casual pie model.
Component cause are the several factors that make up the sufficient pie. A factor that contributes towards dis-ease causation, but is not sufficient to cause dis-ease on it’s own
* Component causes “interact” to produce disease.
Describe the necessary cause pie from the KJ Rothman, 1986) casual pie model.
A factor (or component cause) that must be present for a specific dis-ease to occur. However, it may not cause the disease own its own. EXAMPLE: The bacteria Mycobacterium tuberculosis is a necessary cause of tuberculosis (TB). If someone does not have this bacterium, they cannot develop TB, but having the bacterium alone doesn’t guarantee they will get the disease. Sometimes, a necessary cause will be a component cause.
List some points that are TRUE for the casual pie model.
- You do not need to know every component cause to prevent cases of the diseases.
- Blocking/removing any component cause would result may reduce the risk, but cases may still occur.
- Knowledge of the complete pathway is not a pre-requisite for
introducing preventive measures - Can intervene at any number of points in the pie
What are preventative measures?
Preventative measures mean action to reduce the risk of the disease. E.g: vaccinations, wearing sunscreen to prevent skin cancer.
What does causality mean and whats the difference between causality and association?
It means the exposure directly causes the outcome. Association occurs when the exposure and outcome are linked.
Why can’t we prove causality in human experimental studies?
Because of ethical and practical reasons. We can’t expose harmful things to people because that is unethical and people live in noisy environments where all other factors also contribute to their health.
Describe the key features of epidemiological study?
Most epidemiological studies,
o are non-experimental
o are conducted in ’noisy’ environments in free-living populations
o determine the relationship or association between a given exposure to a cause/s and dis-ease outcome in populations
Epidemiology can also show the statistical association between a potential exposure and outcome.
What does Statistical exposure mean?
Two things are linked — when one changes, the other often changes too.
Does this mean the exposure causes the outcome?
Sometimes, but not always.
What do you need to do when to look for links between Exposure &
Outcome
1.Need sufficient studies done in diverse settings
and adequately limiting random errors, non-random errors (bias) and confounding
2. Judge findings against a framework to see if the association is causal
What does causes of the causes mean for individuals vs populations?
For individuals: “any event, characteristic or other
definable entity, that brings about a change for better or worse in health. Causes of the causes relates to why it drives people to smoke in the first place. For populations it depends on the characteristics and context in which the population exists.
What are downstream and upstream interventions?
Downstream interventions are operate at the micro (proximal) level,
including treatment systems, and disease management. It’s all about the direct actions to deals with management of health issues. Upstream interventions are operate at the macro (distal) level, such as
government policies and international trade agreements. It focuses on the broader factors.
Explain Proximal and Distal determinants (causes of causes) which are DIFFERENT to interventions.
Proximal Determinants:
A determinant of health that is proximate or near to the change in health status; ‘near’ generally refers to any determinant that is readily and directly associated with the change in health status. E.g. lifestyles and behavioural factors related to nutrition or smoking or other exposures.
Distal Determinants:
A determinant of health that is either distant in time and/or place from the change in health
status.
Distal determinants of health are also referred to as ‘upstream factors’. E.g. national, political and legal factors.
What is another name for distal determinant?
Upstream factors.
Describe the level 1 individual of the The Dahlgren and Whitehead Model. This is the very inner CIRCLE.
These are the non-modifiable factors that you cannot change such as age, sex and genes/ biology. Example: Single gene disorders only affect individual level because it only changes one gene of a human. Polygenic inheritance = influences likelihood of offspring
developing a disease, therefore impacting population.
Describe the lifestyle factors.
The importance of
food, exercise, and risky behaviours in relation to health
outcomes.
– Remember the social gradient
* The choices you make as an individual impact on the likelihood
that you will have good(or bad) health
* Habitus: lifestyle, values, dispositions and expectation of
particular social groups ‘learned’ through everyday activities
What is the social gradient?
Thesocial gradientis a concept that explains howhealth outcomestend to improve as you move up thesocioeconomic ladder(i.e., as you have more wealth, education, and social status) and worsen as you move down.
Describe level 2 of the model.
Social and community networks & Living and working conditions
* Families and friends play a significant role in developing ‘normative’
behaviours
* Attitudes and behaviours of people living and working in the local
community influences the sense of what is normal and acceptable
* Social capital - the value of social networks that facilitates bonds
between similar groups of people
– provides an inclusive environment for people from diverse backgrounds
– Civic participation, volunteerism, supportive communities
“it’s not what you know, but who you know”!
Name the 6 environments for level 3 of
the general socioeconomic, cultural and environmental conditions
- Physical
- Built (buildings)
- Cultural
- Biological
- Ecosystem
- Political
Explain the The Current Living Standards Framework and the key 3 aspects to it.
This framework is hat measures the overall well-being and living standards of New Zealanders. There are 3 aspects: our individual and collective wellbeing (resources and aspects
of our lives that are important for the
wellbeing of individuals, families,
whānau and communities). Then there is institutions and governments (role our institutions play
in safeguarding and building our
wealth, as well as facilitating the
wellbeing of individuals
and collectives). Lastly, there is the wealth of NZ which is how wealthy we are in aggregate as a country, including
sources of wealth not fully captured in
the system of national accounts:
human capability and the natural
environment.)
What are the four capitals from the wealth of NZ?
- Social capital that describes the norms and values. Examples: trust, rule of law, crown - Maori relationship, cultural identity, and connections between people and communities.
- Financial capital : Houses, roads and buildings.
- Human capital: People’s skills, knowledge, physical and mental health.
- Natural environment: Land, soil, water, plants animals, minerals and energy sources.
Define structure and agency.
Social and physical environmental conditions/patterns
(social determinants) that influence choices and opportunities
available. Structure shapes or limits what people can do.
Agency – the capacity of an individual to act independently and make
free choices
Agency is what people choose to do within those limits.
What does agency and structure represent on the Dahlgren and Whitehead Model.
Agency= Individual lifestyle factor + social and community networks.
Structure= Social community and general socio-economic, cultural and environmental factors.
What is the
