Public Health Flashcards

1
Q

How to calculate positive predictive value?

A

True Positive / True Positive + False Positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How to calculate negative predictive value

A

True negative / True negative + false negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is negative predictive value?

A

The proportion of people with a negative result who do not have the disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is positive predictive value?

A

The proportion of people with a positive test that actually have the disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How to calculate sensitivity

A

True positive / True positive + False Negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How to calculate specificity?

A

True negative / False positive + true negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Give 3 strengths of cross-sectional studies

A

Quick/cheap

No long periods of follow up

Can be used for large data sets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Give 3 weaknesses of cross-sectional studies

A

Not suitable for rare diseases

Not suitable for diseases with a short duratiopn

Unable to measure incidence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Define sensitivity

A

The percentage of true positives. (The proportion of people who test positive among those who have the disease)

(sensitivity of 90% means 90% of people who have the disease will test positive)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define specificity

A

Percentage of true negatives

(90% specificity = 90% of people who do not have the disease will test negative)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the 5 levels of Maslow’s Hierarchy of Needs?

A

Physiological needs.
Safety needs.
Love and belonging.
Esteem.
Self-actualisation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Define Allostasis

A

The process of achieving stability, or homeostasis, through physiological or behavioural change.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define Epidemiology

A

The study of the frequency, distribution and determinants of diseases and health-related states in populations in order to prevent and control disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define Incidence

A

The rate at which new diseases occur in a population in a certain time period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define Prevalence

A

The proportion of a population found to have a disease at a point in time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define Person-Time

A

Describes the sum of the periods of time that each individual in the study has been at risk.

(in years/months or days) (i.e Person Years)

Used as the denominator in incidence rate calculations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define relative risk. What does it tell us?

A

Describes the risk in one category relative to another.

I.e Ratio of risk of disease in the exposed vs the unexposed.

Tells us the strength of association between a risk factor and a disease.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What calculation can be used to work out relative risk?

A

Incidence in exposed ÷ Incidence in unexposed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Define attributable risk

A

Describes the rate of disease in the exposed that may be attributed to the exposure.

Tells us about the size of effect in absolute terms

20
Q

How is attributable risk calculated?

A

Incidence in exposed - Incidence in unexposed

21
Q

Define Bias

A

Describes a systemic deviation from the true estimation of the association between exposure and outcome

22
Q

Name 2 types of bias

A

Selection Bias

Information Bias

23
Q

What is selection bias

A

The people who choose to participate in screening programmes may be different from those who do not.

Proper randomisation is not achieved

24
Q

What is information bias?

A

Information or measurement bias can be due to observer, participant or instrument error.

25
Q

What is length-time bias?

A

Diseases with a longer period of presentation are more likely to be detected by screening than ones with a shorter time of presentation

26
Q

What is lead-time bias?

A

Screening identifies diseases earlier and so gives the impression that survival is prolonged but in reality survival time is unchanged.

27
Q

What is the Bradford Hill Criteria for Causation?

A

Consistency.
Biological plausibility.
Temporality - cause before disease.
Dose response.
Reversibility.
Strength of association.

28
Q

Name 5 types of study

A

Ecological

Cross-Sectional

Case Control

Cohort

Randomised Control Trial

29
Q

Which type of study uses routinely collected population level date to show trends and to generate hypotheses?

A

An Ecological Study

30
Q

Which type of study looks at the population at a point in time?

A

A cross-sectional or prevalence study.

31
Q

Which type of study compares people with a disease to those without a disease for age, sex, habits, class etc?

A

A case-control study. These are retrospective.

32
Q

Which type of study follows a population over time to see if they’re exposed to the agent in question and if they develop the disease?

A

A cohort or incidence study. These are prospective.

33
Q

What is a RCT?

A

Where a population is randomised to either an interventional or a control group. Often these are blind or double-blind trials.

34
Q

Which type of study is also known as an incidence study?

A

A cohort study - follows a population over time to see if they’re exposed to the agent in question and if they develop the disease.

35
Q

Which type of study is also known as a prevalence study?

A

A cross-sectional study. It looks at the population at point in time.

36
Q

Define primary prevention.

A

Preventing a disease/condition from occurring in the first place. Eliminating RF’s that contribute to the disease.

37
Q

Give an example of a primary prevention method.

A

Immunisations.

38
Q

Define secondary prevention.

A

Detecting a disease as soon as possible in order to alter its course and to improve health outcomes.

39
Q

Give 2 examples of secondary prevention.

A

Screening e.g. cervical smears, breast cancer mammograms.

Low dose aspirin/diet/exercise changes to prevent further heart attacks/stroke

40
Q

Define tertiary prevention.

A

Trying to slow down disease progression, avoiding complications and helping people to manage their illness effectively.

41
Q

Give 2 examples of tertiary prevention.

A

Diabetes management - diet advice, exercise programmes, self-monitoring, annual foot checks etc.

Stroke Rehabilitation

42
Q

Give 4 different types of screening

A

Population based.
Opportunistic.
Screening for communicable diseases.
Pre-employment and occupational.

43
Q

Define bioavailability

A

Refers to the fraction of administered drug that reaches systemic circulation (blood)

44
Q

Give 3 causes of low bioavailability

A

First-pass metabolism (causes drug to be metabolised before adequate plasma concentrations are reached)

Insufficient time for absorption in the GI tract (if drug does not dissolve readily or cannot penetrate the epithelial membrane)

Pervious GI surgery (i.e bariatric surgery)

45
Q

100 drug molecules are ingested. 90 survive the GI tract. 81 make it past the gut wall into the portal vein. Of the 81 that enter the liver, 41 make it into systemic circulation.

What is the bioavailability?

A

41/100 = 41%

46
Q
A