HaDPop

Question 1

What is GFR?

Answer 1

General fertility rate: number of live births per 1000 fertile women between ages 15-44.

Question 2

What is TPFR?

Answer 2

Total period fertility rate: average number of children born to a hypothetical woman in her lifetime (sum of age specific boundaries).

Question 3

What is CDR?

Answer 3

Crude death rate: number of deaths per 1000 population.

Question 4

What is the incidence rate of a disease?

Answer 4

The number of new cases of the disease per 1000 people per year.

Question 5

What is the prevalence rate of a disease?

Answer 5

The amount of people who currently have the disease in a set population.

Question 6

What is the incidence rate ratio of a disease?

Answer 6

The incidence rates of two populations with varying exposures compared to see if the exposure causes the disease.

Question 7

What is a confounding factor?

Answer 7

Something that is associated with both the outcome and exposure of interest, but is not on the causal pathway between exposure and outcome.

Question 8

What can result from confounding factors?

Answer 8

Results distorted so they appear misleading. Can show potential causal links which are actually unfounded.

Question 9

What is SMR?

Answer 9

Standardised mortality ratio: takes into account confounding factors to provide summative figures compared to the general population (O/Ex100).

Question 10

How does SMR take into account confounding factors?

Answer 10

By standardising the date; usually based on age and gender to remove them as confounders.

Question 11

What is variation?

Answer 11

A difference between the observed and actual value.

Question 12

How are confidence intervals calculated?

Answer 12

Lower: value / e.f
Upper: value x e.f

Question 13

What is bias?

Answer 13

Deviation of the results from the truth via certain processes.

Question 14

What is selection bias?

Answer 14

Error due to systematic differences in the ways in which two groups were collected.

Question 15

What is information bias?

Answer 15

Error due to systematic misclassification of subjects in the group.

Question 16

What is the healthy worker effect?

Answer 16

Deficit in morbidity and mortality ascribed to various employment-associated factors when workers are compared to the general population.

Question 17

When are cohort studies used?

Answer 17

When investigating rare exposures or if a disease takes a long time to develop?

Question 18

What is a prospective study?

Answer 18

Study where disease free individuals are recruited and followed up over time.

Question 19

What is a retrospective study?

Answer 19

A study where disease free individuals are recruited and exposure status is calculated using historical data and followed up.

Question 20

What happens in a cohort study?

Answer 20

Disease free individuals are recruited and classified based on exposure status. They are followed up over out extended periods and disease progress is monitored. Incidence rates are calculated.

Question 21

What are internal comparisons and how are they compared?

Answer 21

Where sub-cohorts within the original group are compared as ‘exposed’ and ‘unexposed’ within the cohort. IRR is used.

Question 22

What are external comparisons and how are they compared?

Answer 22

The exposed population is compared to an external reference population. Compared using SMR to remove confounders.

Question 23

How can bussing from the healthy worker effect be removed?

Answer 23

Make comparisons between the test cohort and another occupational cohort.

Question 24

What is a case-control study?

Answer 24

A study where disease free controls and diseased individuals (cases) are recruited and their exposure status is determined using an odds ratio.

Question 25

How is an odds ratio calculated?

Answer 25

Cases and controls along top of the table. Exposed and unexposed on the side of the table. OR=(ad/bc).

Question 26

When are case control studies used?

Answer 26

When rare diseases are being investigated.

Question 27

How many more controls are used than cases in a case control study and why?

Answer 27

Around 5 times more. Any less and the error factor increases but any more and the error factor is barely reduced despite the increase in cost.

Question 28

How is the confidence interval calculated in a case control study?

Answer 28

OR x e.f. or OR/ e.f.

Question 29

How can selection bias affect case control studies?

Answer 29

Participants don't represent the general population.

Question 30

How can recall bias affect a case control study?

Answer 30

Exposure status is incorrectly determined due to looking back at the history to determine exposure status.

Question 31

How is confounding reduced in a case control study?

Answer 31

Cases and controls are matched based upon similar details.

Question 32

How is a randomised control trial carried out?

Answer 32

Source of patients is identified. Eligible patients are invited to participate and they are randomly and fairly allocated to a treatment. Patients are all followed up in the same way and losses are minimised and compliance is maximised. Data is analysed to obtain results.

Question 33

How are outcomes measured in a randomised control trial?

Answer 33

Using intention to treat analysis.

Question 34

What is the purpose of the Bradford-Hill criteria?

Answer 34

To determine wether causal-effect relationships have been established in a study. The more criteria present, the more likely causality is.

Question 35

What are the Bradford-Hill criteria?

Answer 35

Strength of association, specifity of association, consistency of association, temporal sequence, dose response, reversibility, biological plausibility, coherence of theory. (Some Sick Cunts Tape Dinosaurs Round Bradford's Cock).

Question 36

How are losses minimised in a randomised control trial?

Answer 36

Follow up appointments at practical times, no coercion or inducements, honesty to the patient.

Question 37

How is compliance maximised in a randomised control trial?

Answer 37

Simplified instructions, allow patient to ask any questions they have, make the trial simple and accessible for the patient.

Question 38

How can compliance be measured in a randomised control trial?

Answer 38

Using blood tests,murine samples, etc.

Question 39

What is a systematic review?

Answer 39

A compilation of primary studies.

Question 40

What features should studies have in a systematic review?

Answer 40

They should be relevant and credible as well as being transparent, reproducible and explicit. (Usually randomised control trials). Both published and unpublished studies should be used.

Question 41

What is a meta analysis?

Answer 41

A quantities synthesis of primary studies within a systematic review.

Question 42

What is the fixed effects model used in a systematic review?

Answer 42

Model that assumes the studies used are homogenous and any variation between the data comes from within: study variation.

Question 43

What is the random effects model used in systematic reviews?

Answer 43

Model that assumes studies are heterogenous and variation between data comes from within: study variation and in-between study variation.

Question 44

How can publication bias be determined?

Answer 44

Using a funnel plot: if the plot is well balanced the plot will show a funnel shape, if it is biased the plot will vary in shape.

Question 45

What is CBR?

Answer 45

Crude birth rate: number of live births per 1000 population.