Understanding Health Inequalities Flashcards
Why is it difficult to identify causes of illness in public health data?
Public health data is observational data
We need experimental data
What is meant by experimental data?
A group of people with similar characteristics is randomly divided into 2 groups
The only difference between these 2 groups is exposure status
If you see a difference in outcome, you know it is due to exposure as all the other characteristics are the same
What is meant by observational data?
The selection of people in the exposed and unexposed groups is NOT random
The groups will be different in exposure, but also an array of other characteristics
You don’t know which characteristic results in the difference in health
Under what circumstances is an association most likely to be causal?
An association is most likely to be causal when the exposure is both necessary and sufficient for the outcome to happen
What is meant by necessity?
What is meant by sufficiency?
Necessity:
The exposure must be in place in order for the outcome to happen
Sufficiency:
The exposure always leads to an outcome
Why are risk factors in public health data often neither necessary or sufficient?
Illness can happen without the risk factor of interest
e.g. Different exposures may lead to the same illness
presence of the risk factor does not always lead to illness
Why are associations often seen in observational data?
- Exposure could cause the outcome
- Reverse causation - the outcome may actually be causing the exposure
- Bi-directional causation - there is a feedback loop between exposure and outcome
- Confounding - exposure and outcome are both consequences of something else
What are the three conclusions that must be considered when it comes to public health data?
- We cannot observe causal effects in public health data - only associations between risk factors and health outcomes
- Reverse causation and confounding bias are the main challenges to drawing causal relationships from public health data
- Statistical association does not necessarily imply a cause and effect relationship
Under what 3 circumstances is a causal relationship from public health data more plausible?
- Potential sources of confounding have been thought about and dealt with in some way
- There is less potential for reverse causation
- The association meets a wider set of criteria that are consistent with causality
How may potential sources of confounding have been thought about and dealt with in some way?
- Stratifying into groups can identify whether there is potential for confounding bias
- Statistical adjustment in a regression model allows us to take into account multiple confounders at the same time
How can you identify if there is less potential for reverse causation?
Look at longitudinal data
e.g. Levels of depression amongst unemployed and employed throughout a period of time
Use the same data and swap around
e.g. what is the level of unemployment amongst those who were and weren’t diagnosed with depression within the same time frame
What guidelines are used to think about whether something is causal or not?
Bradford Hill Guidelines
This is a set of 9 guidelines
What are the 9 components of the Bradford Hill guidelines?
- Strength
- Consistency
- Specificity
- Temporality
- Biological gradient
- Plausibility
- Coherence
- Experiment
- Analogy
What is meant by ‘strength’?
Strong associations are more likely to be causal than weak ones
What is meant by consistency?
Has the same association been observed in different populations?
Has the same association been observed using different methods?
What is meant by specificity?
Is the association with an exposure limited to, or greatly increased in, specific groups?
What is meant by temporality?
Did the exposure precede the outcome?
It cannot be a cause if it preceded the outcome
What is meant by biological gradient?
Do greater levels of exposure co-occur with a greater risk of occurrence?
higher level of exposure = more likely to get the outcome
What is meant by plausibility?
Is there a plausible biological (or social) mechanism linking the exposure with the outcome?
What is meant by coherence?
Do the temporal patterns of exposure fit with the observed disease patterns?
e.g. do rising levels of unemployment co-occur with rising levels of depression?
What is meant by experiment?
Do preventative actions with regard to the exposure alter the risk of the outcome?
if there is an intervention to take away the risk factor, is there a subsequent improvement in health?
What is meant by analogy?
Is the observed association supported by similar associations?
e.g. smoking is a risk factor for lung cancer
is there also an increased risk of lung cancer in those exposed to passive smoking?
Why are the Bradford Hill guidelines used?
They are not rules that must be fulfilled before an association can be judged as causal
they are ways of examining if cause and effect is a reasonable inference
What is the difference between equality and equity?
In equality, everyone is given the same level of healthcare
You are not providing greater care to the people who need more care
In equity, you are giving someone as much care as they need to become healthy
What is the definition of health inequality?
Differences in health status or in the distribution of health determinants between different population groups
Some health inequalities are unavoidable
e.g. Difference in motility in the young and elderly
What is the definition of health inequity?
Health inequalities that are unnecessary and avoidable, as well as unfair and unjust
they may be attributable to factors beyond the control of those concerned
WHat is the difference between equal and equitable healthcare?
Equal healthcare:
- giving everyone the same level of care
- e.g. Same budget for every patient
Equitable healthcare:
- giving everyone the level of care they need to be healthy
- e.g. Larger/smaller budgets for those with lesser/greater needs
How does care need to be changed in order to reduce health inequalities?
Care needs to be equitable in order to reduce health inequalities
What is meant by inequalities becoming structural?
There is a structural way that social and health disadvantages develop to affect a group in society
e. g. Poverty, single parenthood
e. g. Social disadvantage can cause mental illness, and the other way around
inter-generational transmission means that the disadvantages that affected the parents may be passed on to the children
What is meant by overt racism?
Speech or behaviour that demonstrates a conscious acknowledgement of racist attitudes or beliefs
What is meant by structural racism?
A system in which public policies, institutional practices, cultural representation, and other norms work in various, often reinforcing ways to perpetuate racial group inequity
social and political movements in society to eliminate racism mainly target overt racism
What are examples related to health of racism in the UK?
There is a relative risk of common mental disorders and psychosis in individuals exposed to racial harassment
black women in the UK are 4 times more likely to die in pregnancy compared with white women
