progress test ( lectures 14-22)

Question 1

what is population health?

Answer 1

the health outcomes of a group of individuals including the distribution of such outcomes wihthin the group.

Question 2

how is health distributed in NZ?

Answer 2

there are two important patterns
-ethinicity
-socioeconomic status

Question 3

how is socioeconomic status measured?

Answer 3

takes into consideration factors such as occupation, income and education.
measured through deprivation the NZDep scales

Question 4

how is NZDep measured?

Answer 4

area based measurement of deprivation, areas of 100-200 people (suburbs). given a decile score based on your deprivation. 10= most deprived, 1= least

Question 5

what determines health?

Answer 5

general socioeconomic, cultural and envrionmental conditions
living and working conditons
social and community influences
individual lifestyle factors
age,sex and hereditary factors

Question 6

what is a DALY and what does it measure?

Answer 6

a integrated measure of health loss. it is the sum of years of life lost and years lived with disability . One DALY represents the loss of one year of life lived in full health.

Question 7

why has the DALY rate decreased by the total number of DALYS increased?

Answer 7

the rate has increased due to a reduction in early deaths, have the ability to keep people living longer.
The total number of DALY’s is increasing because of nz growing and aging population which sees an increase in years of poor health and disability,

Question 8

demographic transition vs epidemiological transition

Answer 8

demographic= changes in population death and birth rates over time, growth and change in population over time

epidemiological= changes in population disease patterns over time non & communicable diseases

Question 9

How has demographic transition changed over time

Answer 9

birthrate= decreased, more babies are surviving so people are having less
deathrate= decreased, people are living longer with less diseased better healthcare etc
total population= increased, the median age of the population is also increasing.

Question 10

how has epidemiological transition changed with time?

Answer 10

communicable disease has decreased due to better hygiene, nutrition etc .
non communicable disease= increased

Question 11

what is disease prevalence and why do we measure it

Answer 11

the proportion of a population who have the disease at a point in time
helps to show the burden of disease and where resources may need to be allocated within a population

Question 12

how to calculate prevalence

Answer 12

number of people with the disease at a given point of time/ the total number of people in the population at that point in time.

Question 13

what are the limitations of prevalance?

Answer 13

difficult to asses the development of the disease
the duration of the disease influences its prevalence (eg longer disease higher prevalence)

Question 14

how to calculate incidence proportion

Answer 14

number of people who develop the disease in a specified period/ number of people at risk of developing the disease at the start of the period

Question 15

how to calculate incidence rate?

Answer 15

number of people who develop the disease in a specified period/ number of person years at risk of developing the disease

Question 16

when is it important to enforce age standardisation

Answer 16

when age structures differ and the disease risk varyies by age

Question 17

what is a cross-sectional study and what can it measure?

Answer 17

measures exposures and/or outcomes at one point in time
eg census
it measures the prevalence

Question 18

what are 4 limitations of cross sectional studies

Answer 18

1) cannot determine temporal sequencing- dont know whether the exposure or the outcome came first (chicken and the egg)
2) measures prevalence not incidence
3) not good for studying rare outcomes or exposures- may find very few of what you are looking for therefore not an accurate representation
4) not good for assesing variable and transient exposures or outcomes

Question 19

what are some benefits of a cross sectional study

Answer 19

you can assess multiple exposures and outcomes
can be less expensive
relatively quick
depending on your question, good when you have stable exposures and outcomes and it can generate a hypothesis

Question 20

what is an ecological study and how do you typically identify one?

Answer 20

You compare exposures and outcomes across groups not individuals.
usually compare countries or larger areas.

Question 21

what are 2 limitations of ecological studies?

Answer 21

1) ecological fallacy- you cant desrcibe individual charactaristics within the group, everything catagorised on the group as a whole.
2)cant control for confounding- when there are other factors which could impact the relationship.

Question 22

what are some benefits of ecological studies?

Answer 22

data is often routinely collected for the populations so it may be relatively easy to do and inexpensive.

Question 23

what does PECOT stand for

Answer 23

Population
Exposure
Comparison
Outcome
Time

Question 24

source vs sample population

Answer 24

source is the population that you are recruiting from for the study
sample is the people from the population who are actually in the study

Question 25

what is a cohort study?

Answer 25

individuals are defined on the basis of presence or absence of exposure to a suspected risk factor
measures exposures and outcomes. see whether people are exposed to a risk factor, follow them up over time and see if they develop what you are interested in

Question 26

what is vital for collecting your sample population in a cohort study

Answer 26

the sample population must not already have the outcome of interest.

Question 27

what can you calculate from cohort studies?

Answer 27

incidence proportion/rate
relative risk
risk difference

Question 28

what are three things you have to consider carefully for cohort studies?

Answer 28

1) ideally have a random selection independent of exposure status
2) can you be sure that the sample population does not already have the outcome
3) have particpants been correctly classified into exposed or comparison group.
4) follow up time, have they changed exposure status over time, has everyone been followed up over the entire study, how long do particpants need to be followed up (how long would the exposure take to develop)

Question 29

what are the 4 strengths of cohort studies?

Answer 29

• can determine a temporal sequence between exposure and outcome
• can examine multiple outcomes from an exposure
• can calculate incidence
• good for rare exposures

Question 30

what are some limitations for cohort studies?

Answer 30

• loss to follow up, can lead to bias
  -potential for misclassfification of exposures and outcomes
• not good for rare outcomes
  -time consuming and expensive

Question 31

how does a historical cohort study differ from a typical cohort study?

Answer 31

A historical study starts at the outcome.
you see who ends up with the outcome then trace back to look at whether they were exposed or not.

Question 32

observational vs intervention studies

Answer 32

observational studies we dont go in and change things we just observe them, and dont change their exposure status.
intervention we may give exposures etc to certain groups

Question 33

what is a case control study and what does it measure?

Answer 33

you identify people with the outcome, then you find people without the outcome and you compare their exposure likelihood leading up to that.
This allows you to calculate odds.

Question 34

what is the main logic of case-control studies?

Answer 34

Is the exposure associated with the outcome?

Question 35

what do odds ratios tell us ?

Answer 35

how many times as likely cases are to have the exposure compared to the controls

Question 36

strengths of case control studies

Answer 36

can asses multiple exposure, can determine temporal sequencing, can look at rare outcomes and transient exposures, quick and inexpensive

Question 37

limitations of case control studies

Answer 37

can only study one outcome, difficult to select people into the appropriate control group, potential selection and recall bias

Question 38

what is a randomised control trial and what does it measure

Answer 38

testing effects of treatments/ interventions on participants randomly allocated to groups. you always have a comparison/ control group. looking to see whether the intervention increases or decreases the risk of the outcome. You can measure incidence

Question 39

what is concealment of allocation and why is it important

Answer 39

the way that individuals are allocated needs to be concealed and unpredictable , because this ensures there isnt any bias.

Question 40

what are three potential sources of bias?

Answer 40

• blinding
• loss to follow up (death, people moving away)
  -non adhearance (people not doing what theyre supposed to in terms of getting the intervention etc)

Question 41

what are three ways you can protect randomisation

Answer 41

• large numbers in the study
  -concealment of allocation
  -intention to treat analysis

Question 42

what does NEAC stand for and what are they

Answer 42

National ethics advisory committee, the new zealand ethics committee that has established different principles to ensure that acceptable research is being carried out.

Question 43

beneficence vs non-malefiecence

Answer 43

beneficence is the duty we have to help people where as non maleficence is the duty we have to not intentionally harm people.

Question 44

what is the basic idea of clinical equipoise

Answer 44

the idea that the participant should not suffer any substantial disadvantage from being in the study