Health and disease

Question 1

What is the equation for incidence rate of a disease

Answer 1

Incidence rate = events / (people X time)

Question 2

What are the units for incidence rate of a disease

Answer 2

Number of events, per person, per year

Question 3

What is the incidence rate of a disease

Answer 3

It is the new events of a particular disease

Question 4

What is prevalence of a disease

Answer 4

It is a measure of the existing cases of a disease.

Question 5

What is the equation relating prevalence to incidence of a disease

Answer 5

Prevalence = incidence rate X length of disease

Question 6

What is the incidence rate ratio

Answer 6

It compares the incidence rate of disease between two groups which can be useful in identifying the aetiology of a disease or the efficacy of a treatment.

Question 7

What is the incidence rate ratio equation

Answer 7

Incidence rate ratio = observed rate in exposed group / observed rate in unexposed group. 1 = no difference between the two groups

Question 8

What is a confounding factor

Answer 8

Is a type of systematic variation that independently act on both the exposure and the outcome of a disease

Question 9

What is the standardised mortality ratio and what is it useful for

Answer 9

It is a ratio of mortality rate where age and sex confounding factors are removed, by comparing the observed / to the expected of the same age and sex bracket. The figure is usually multiplied by 100, where 100 represents parity between the two groups

Question 10

What is doctor foster

Answer 10

A hospital guide for potential patients

Question 11

What three things should be considered when making a target

Answer 11

Appropriateness of measure

Suitability of target level

Consequential effects

Question 12

What is a census

Answer 12

A measure of the population through the simultaneous recording of demographic data by the government of a particular time, to a group of persons who live in a particular geography

Question 13

Characteristics of a census

Answer 13

Run by government, defined area, simultaneous, universal, regular intervals

Question 14

What does a census reveal

Answer 14

The population size, structure and characteristics

Question 15

What are the 3 factors that affect the population size

Answer 15

Births, deaths, migration

Question 16

What is the crude birth rate CBR and when is it used

Answer 16

Number of live births per 1000, to describe the impact of births on population size as compared to migration and deaths

Question 17

What is the general fertility rate GFR

Answer 17

Number of live births per 1000 of the female population in the 15-44 year bracket. Used to compare fertility rates of women in different populations

Question 18

What is the advantage of the general fertility rate over the crude fertility rate

Answer 18

The GFR only applies to the section of the population capable of giving birth

Question 19

What is the total period fertility rate TPFR?

Answer 19

It is the sum of the fertility rate of women at each year of their fertile age.

Question 20

What is the advantage of the TPFR

Answer 20

The TPFR averages the fertility rate over a lifetime, without being influenced by the number of women in each age group. Providing a value of the hypothetical number of children a woman would have. It is not influenced by the number of people at each age range. For example, excess hold people, with a lower overall birth rate, would skew the GFR

Question 21

What is fecundity

Answer 21

The physical ability to reproduce

Question 22

What is fertility

Answer 22

The realisation of the potential to reproduce

Question 23

What are conceptions

Answer 23

The total number of births, miscarriages and abortions

Question 24

What birth records are compulsory

Answer 24

Birth notification within 36 hours of birth, birth registration within 42 days

Question 25

What are the compulsory ways to record death

Answer 25

Death certification by the doctor, death registration within 5 days by the realtime usually

Question 26

What is the crude death rate

Answer 26

Number of deaths per 1000 of population

Question 27

What is Age Specific Death Rate ASDR

Answer 27

Number of deaths per 1000 within a given age range

Question 28

Why record death rates

Answer 28

Analyse patterns in death rates, deliver services, identify health problems, effects on the population

Question 29

What is a sample

Answer 29

A representative group of a larger population

Question 30

What is a sampling frame

Answer 30

A method to help you select a sample

Question 31

What is the p value

Answer 31

The probability that an observation is true, given that the null hypothesis is also true.

Question 32

What is the significance of a p-value less than 0.05 and what are the limitations

Answer 32

The result gives sufficient evidence to reject the null hypothesis, we are confident that the observation did not happen by chance.

However, this does not allow us to accept the alternative hypothesis.

Statistical significance depends on sample size, it is arbitrary and may not be clinically significant.

Question 33

What is random variation

Answer 33

A number of samples can all vary in their nature, by the random effects of selecting the sample. Therefore they all have different individual qualities, but come from one central quality in the popualtion which is true and needs to be discovered

Question 34

What is a confidence interval

Answer 34

The range within which you are (normally 95%) sure that the true popualtion value lies

Question 35

How do you determine the 95% confidence interval using error factors

Answer 35

Upper limit = observed value X error factor

Lower limit = observed value / error factor

Question 36

What is the error factor equation for a rate of standardised mortality ratio

Answer 36

Error factor = exponential (2 X ^^^[1/no of cases])

Question 37

What is the error factor equation for a rate ratio?

Answer 37

Error factor = exponential (2 X ^^^[1/population A + 1/population B])

Question 38

What is a cohort study

Answer 38

A study that identifies a group of people free of an outcome and follows them over time to see how their different exposures affect the outcome

Question 39

What are the advantages of a cohort study

Answer 39

Can be done retrospectively as well as prospectively (concurrent).

Can look at risk factors that cannot be controlled experimentally, for ethical reasons, eg. Alcohol during pregnancy

You can obtain more detailed information especially in prospective studies as more exposures can be included.

You can study confounding issues

You can investigate causation, especially if there is a strong dose affect with the risk factor

Question 40

What are person years in a cohort study

Answer 40

The amount of years that a person actively participated and was followed up in a study. Person years = number of people X length of study