Public Health/ Genetics/ Causation Flashcards

1
Q

What is absolute risk?

A

Incidence of disease in a given population
Can be further divided into absolute risk for exposure vs non-exposure to determine if exposure plays a role in disease prevalence.

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2
Q

What is relative risk?

A

Tells you whether people who have a given exposure or risk factor have a difference in risk to developing disease
RR= incidence in exposed/ incidence in not exposed

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3
Q

How is relative risk interpreted?

A

If RR = 1, risk in exposed = risk in not exposed so no association
If RR > 1 risk in expose > risk in not exposed (positive association, (causal?))
If RR < 1 risk in exposed < risk in not exposed (negative association (protective?))

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4
Q

What does a case-control study evaluate?

A

Involves a case (disease) and a control (no disease) and works backwards to try and determine exposures.
Works using an odd ratio

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5
Q

What is an odds ratio?

A

(Odds that the number of positive cases were exposed) / (odds that the controls were exposed)

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6
Q

How do relative risk and odds ratio differ?

A

RR is gold standard but obtained through cohort study
RR will give better measure with a highly prevalent disease

RR=ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group

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7
Q

What is attributable risk?

A

Incidence of cases among those exposed that are due to exposure/risk factor
Also termed absolute risk reduction, as it is the difference in absolute risk for exposed vs non-exposed

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8
Q

Why is attributable risk important when evaluating public health?

A

Will allow you to asses how relative and absolute risk impact the population as a whole by looking at the risk of developing the disease if you have/haven’t got the risk factor, and how many people in the public actually have that given risk factor.

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9
Q

What are the differences between the following audits; research, clinical, and service evaluation?

A

Research: Tries to derive generalisable new knowledge including studies that aim to generate hypotheses and test them. Addresses clearly defined aims, questions and objectives.
Clinical: Aims to produce information to inform delivery of best care. Answers question “does this service reach a predetermined standard?”. Involves intervention in use only.
Service: Defines/judges current care. Answers question “what standard does this service achieve” without reference to the actual standard. Involves intervention in use only.

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10
Q

What things can be audited?

A

Structure (the resources and staff available, i.e. skill mix of staff, patient access to see GPs), Process (amount and type of activity), outcome (result of intervention i.e. pain relief, patient satisfaction)

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11
Q

What do placebo effects rely on?

A

Extrinsic factors like trust, emotional engagement with clinicians, social/physical value of interaction/intervention, setting, anticipation and expectation of clinical improvement, placebo type (large pill, red pill, injection)

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12
Q

What neurobiological mechanisms are involved in placebo effects?

A

Neurotransmitters (endorphins, cannabinoids, and dopamine)
Activation of specific, quantifiable, and relevant areas of the brain (prefrontal cortex, anterior insula, rostral anterior cingulate cortex, and amygdala in placebo analgesia)

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13
Q

What can placebos be used to treat?

A

Symptoms, rarely treats disease

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14
Q

What is a proband?

A

Person who brings the family to the attention of medical genetics team.
Shown by an arrow pointing to them

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15
Q

What is a consultand?

A

Person who has come to genetics for advice, shown by the letter C.

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16
Q

What is a consanguineous relationship and how is it shown on a pedigree?

A

When two people who are in a relationship have a blood relation.
Shown by a double line connecting them

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17
Q

How does a dominant disease appear on a pedigree?

A

Vertical inheritance is seen in multiple generations.

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18
Q

How does a recessive disease appear on a pedigree?

A

Horizontal, one generation appear to be impacted

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19
Q

What is autosomal inheritance?

A

Genetic mutation inherited on chromosomes 1-22, not on sex chromosomes.
It will typically occur in males and females, and if a mutation is passed from father to son it is very likely autosomal (due to father only donating 1 y chromosome)

20
Q

What is knights move inheritance?

A

Two males related through unaffected female.
Only males affected
X-linked recessive inheritance (the female is carrying the mutation).

21
Q

What is triple X syndrome?

A

Fertile, possibly slight reduction in IQ

22
Q

Why are sex linked mutations not as severe as autosomal mutations?

A

X inactivation: All females inactivate an X chromosomes in all cells, so in an individual with an extra one, every extra x is inactivated

23
Q

What is Turner’s syndrome?

A

Lack of an X chromosome in female.

Shortened stature, infertility, neck webbing, lymph oedema

24
Q

What is Kleinfelter syndrome?

A

Inheritance of an extra X chromosome in males.
Can result in breast growth and infertility in males, and failure to finish puberty, and possibly slightly lowered IQ in comparison to siblings

25
Q

What is Duchenne muscular dystrophy?

A

Most common muscular dystrophy.
X-Linked recessive mutation, therefore it mainly impacts males.
Life expectancy is reduced, and most die within 20s
May require ventilation while sleeping

26
Q

What is Patau Syndrome?

A

Trisomy 13
Incompatible with life past a few weeks of birth as chromosome 13 has many genes. Mosaic inheritance may result in longer life.
Cleft lip and palate, small head (microcephaly), severe heart difficulties, polydactyly (extra digits)

27
Q

What are the key features of causation?

A

Exposure preceded outcome

Absence or presence of exposure determines outcomes

28
Q

What is the difference between causality and correlation?

A

Causality shows that a specific exposure causes a specific outcome
Correlation links trends of a given exposure and outcome, without assuming the exposure causes the outcome

29
Q

What is a necessary cause? Give an example

A

When a cause is needed in order for the outcome to take place, but it can be present without the outcome occurring i.e. exposure to mycobacterium potentially resulting in tuberculosis

30
Q

What is sufficient cause? Give and example

A

Cause will always initiate the outcome. If the cause is present, the outcome will occur, although the outcome can occur without the cause being present. I.e. Rabies is fatal, and will always result in death, however death can cause due to other causes.

31
Q

Why would the term risk factor be used instead of causal?

A

Its difficult to prove causation and so epidemiologists are reluctant to make thorough causal inferences.
A certain risk may cause a multitude of pathologies, like smoking causing many types of disease.

32
Q

What is the line model of causation?

A

A line is drawn, connecting genetics and environmental causes.
Typically diseases fall within the centre, demonstrating the disease is a cause of both factors.

33
Q

What is the triangle model of causation?

A

Primarily for infectious diseases.
Shows the interaction of multiple factors;
Agent (infection, radiation, chemical, physical, nutrition)
Host (genetics)
Environment (external; biological, physical, social environment).
They interplay with one another to determine the likelihood of an outcome occurring.

34
Q

What is the wheel model of causation?

A

A true multi-causal model.
Host is surrounded by the biological, social, and physical environment.
Important as it identifies the importance of external factors, like social determinants, and the role they play in causation.

35
Q

What is the web model of causation?

A

A true multi-causal model.
Connects all factors of causation (phenotypes, environment, behaviour, genes) to disease (bigger emphasis on non-communicable disease).
Important as shows how all these factors influence each other.

36
Q

What is the pies model of causation?

A

Sufficient component model of causation.
Was to build on web and wheel models to illustrate how the strength of causal factors is affected by other causal factors.
All of the pie needs to be present to cause an outcome. All factors don’t need to be identified to prevent the outcome, only one that is sufficient.

37
Q

What is epidemiology?

A

The study of the patterns of disease, health states, and their risk factors.

38
Q

What are the Bradford Hill Viewpoints of causality?

A
  1. Strength of association
  2. Consistency
  3. Specificity
  4. Temporality (timing)
  5. Biological gradient
  6. Plausibility
  7. Coherence (no conflicting data)
  8. Experiment (statistical significance doesn’t mean substantial association)
  9. Analogy
39
Q

Why is evidence in epidemiology an important point?

A

Just because clinical significance is proven, doesn’t mean action should be taken.

40
Q

What are important considerations to take into account when evaluating Hill’s viewpoints?

A

Statistical significance should not be mistaken for evidence of a substantial association.

Association does not prove causation (other evidence must be considered).

Precision should not be mistaken for validity (non-random errors exist).

Evidence (or belief) that there is a causal relationship is not sufficient to suggest action should be taken.

Uncertainty about whether there is a causal relationship (or even an association) is not sufficient to suggest action should not be taken.

41
Q

What is sensitivity in terms of screening? What is the calculation for it?

A

Identifying the total number of people who have the disease of interest
Disease present in positively screened people, divided by total people with disease

42
Q

What is specificity in terms of screening? What is the calculation for it?

A

How good a test is at identifying the total number of people who do not have a given disease
Total number of people who don’t have the disease and tested negative during screening, divided by total of people with no disease

43
Q

What is a receiver operating characteristic curve?

A

Plot sensitivity on y axis, and specificity on the X axis (false positive area), and help to compare the two values to determine the ideal type of screening test.
The larger the area under the curve, the better the test is, as it means higher sensitivity, and higher specificity (less false positives)

44
Q

What is positive predicted value?

A

The likelihood that someone with a positive test HAS the disease

45
Q

What is the negative predicted value?

A

The likelihood that someone with a negative test doesn’t have the disease

46
Q

What are the roles of Screening Quality Assurance Services?

A

Assess the quality of local screening programmes
Monitor compliance with standards
Support services with improving quality
Undertake regional level quality assurance visits