Public Health Flashcards
Who is the advisory team for UK vaccines?
Joint Committee on Vaccination and Immunisation
The injection technique for BCG is?
Intra dermal
What are the three C’s of outbreak management?
Confirm
Control
Communicate
Which year was BCG introduced in the UK?
1950
Define screening
Screening is the process of identifying healthy people who may have an increased chance of a disease or condition.
The screening provider then offers information, further tests and treatment. This is to reduce associated problems or complications.
Is screening always a choice?
Yes
What are the 2 main categories screening is normally categorised into?
Based on age.
antenatal/newborn
and
young person/adult
What does UK NSC stand for?
The UK National Screening Committee
What causes the differences in what screening services are available in England, Northern Ireland, Scotland and Wales?
The NSC makes UK-wide policies but it is up to each part of the UK to determine when, and how, to put those policies into practice.
Who chairs the UK NSC?
The UK National Screening Committee (UK NSC) is chaired by the Deputy Chief Medical Officer for England.
What are the criteria that are used to assess the viability, effectiveness and appropriateness of a screening programme?
- The condition
- The test
- The treatment
- The screening programme
The Infectious Diseases in Pregnancy screening programme tests for:
HIV
Syphilis
Hep B
Define Incidence, and how it may be measured.
The number of instances of illness commencing, or of persons falling ill, during a given period in a specified population.
More generally, the number of new health-related events in a defined population within a specified period of time.
It may be measured as a frequency count, a rate or a proportion.
Define Prevalence
The total number of individuals who have an attribute or disease divided by the population at risk of having that attribute or disease either
(a) at a specified time (point prevalence),
or
(b) over a specified period (annual, lifetime, one year; period prevalence).
The relationship between incidence and prevalence…
Prevalence = Incidence x Duration
Why is Point prevalence is always expressed as a proportion?
There is no duration of observation to take into account.
How would you calculate incidence over a set number of years?
no. of NEW incidence cases / time all the individuals have been under observation
How would you calculate period prevalence over a set number of years?
the number of (prevalent) cases / length of
time that all individuals were under observation during that time
Define risk (absolute risk) and how its calculated
The probability of an event.
the number of events
divided by
the total population at risk over a given time period
How to calculate relative risk
Risk in group 1 / Risk in group 2
Finds a result, peoples in group 1 are x times more likely to … than group 2
How to calculate risk difference (absolute risk difference)?
x = Risk in group 1 - Risk in group 2
(For every 100 people in group 1, there will be x more cases compared with group 2)
Takes into account how common the underlying condition is (i.e. its prevalence) in the population
What does relative risk as an umbrella term describe?
risk ratio and rate ratio.
How to calculate odds?
number of events / number of non-events
prob of event/ (1 - prob of event)
What is implied if if the odds of any event occurring is greater than 1…
it implies that the event is more likely to happen than not happen
How to calculate odds ratio
odds of exposure in one group / odds of exposure in the other group.
(another measure to compare risks in groups. The further the number is from one, the more likely it is that those with the condition have the exposure compared to those without the condition)
Why are Relative risks (rate ratios or risk ratios) preferable to odds ratios?
Relative risks (rate ratios or risk ratios) are preferable to odds ratios as they allow the calculation of the risk of developing the condition (unlike odds ratios).
Main difference between rates and risks?
rate takes into account the amount of time each person in the study was at risk for
10 stages of an outbreak investigation
- Determine the existence of an outbreak
- Implement immediate control measures
- Define a case
- Find the cases
- Epidemiological investigation
> Descriptive Study
> Analytical Study - Microbiological investigation
- Environmental Investigation
- Make Conclusions
- Implement more specific control measures
- Communicate
What is an ecological study?
In an ecological study the unit of observation is at GROUP/population/ community (ecological) level. The disease/outcome and the exposure of interest are measured in a number of populations and their relationship is examined.
APPLIES TO GROUPS, NOT INDIVIDUALS. Used to compare groups/populations in different locations or times.
What are Cross-sectional studies?
Cross-sectional studies are usually DESCRIPTIVE studies which may show an association between exposure and outcome, although an analytical element can be built into them.
Cross-sectional studies consist of a single examination of a population without any follow-up, i.e. data are collected at one POINT IN TIME. They provide a ‘snapshot’ of a population
What are the 3 main categories of Study Design?
Descriptive
Observational
Interventional
The difference between cohort and case-control studies?
In case-control studies, the outcome has already occurred at the time of investigation.
In cohort studies, the outcome of interest has not
occurred at the start of the investigation. People with and without the exposure of interest are followed up to examine the proportion in each group who go on to develop the outcome of interest.
Why is it that the only statistical measure we can use in
case-control studies is the odds ratio?
as the investigator chooses the number of cases and controls, we cannot calculate risk (of developing disease) and measures of relative risk.
Name an additional measurement that can be used in random controlled trials?
An additional measure that is commonly used is the NNT (number needed to treat).
How to calculate NNT?
The NNT is the inverse of the absolute risk difference (or 100 divided by the absolute risk difference if expressed as a percentage).
What does the NNT show?
The NNT is a useful measure which provides an indication of the effort required to achieve one additional cure.
It provides a single number to consider the balance between benefits, costs and harm when the main outcome of interest can be defined as a binary event or health state
What is the PICO framework?
A helpful structured approach for developing questions about interventions.
patient/population, intervention, comparison and outcomes
Which of the study designs can be used in outbreak investigation?
Case-control
Cohort
Which of the following is the highest form of evidence?
Case Control Study, Meta Analysis, RCT, or Expert Opinion
Meta Analysis
Name some things that are considered in the Index of Multiple Deprivation?
Income Deprivation Employment Deprivation Health Deprivation and Disability Education Skills and Training Deprivation Barriers to Housing and Services Living Environment Deprivation Crime
What are the Bradford Hill criteria used for?
Help indicate causation
Define confounding
Confounding is when the observed association is due, totally or in part to the effects of differences between the study groups (other than the risk factor of interest) that alters their risk of developing the outcome of interest.
For a variable to be a confounder, it…
must be independently associated with the outcome
must be associated with the exposure
Should not lie on the causal pathway between exposure and disease.
Name the 4 major models used to explain socio-economic inequalities in health.
Behavioural model
Materialist model
Psycho-social model
Life-course model
Define sensitivity of a test
The proportion of people truly with the disease that test positive
What is the prevention paradox?
Prevention programmes that have a large impact on a population level may have little or no benefit for each participating individual
