Health Pop ESA 1

Question 1

What is demographic transition? What 3 things may it have an effect on?

Answer 1

Stages a country has to go through going from a non-industrial to industrial country. Effects on ageing, disability and SDI (sociodemographic index )

Question 2

What is the difference between statistics and probability?

Answer 2

Statistics you know whats in your hand (sample) you want to know whats in the pot (population)

Probability you know whats in the pot (population data) you want to know the chance of it being in your hand (e.g. risk)

Question 3

Confidence interval

Answer 3

Is the range that is likely to contain the mean of the population 95% of the time

Question 4

Name 3 global determinants of health

Answer 4

• Global warming
• Sociodemographic factors (demographic transition, economic transition etc)
• Population factors (e.g. pop size, shape, age/sex specific info)

Question 5

What is the difference between external vs internal validity problems in terms of selection bias?

Answer 5

External validity issues arise when the sample is not representative of population so generalisations occur e.g surveying sexual health patients on sexual behaviour

Internal validity is when you compare two samples that are not from the same population, e.g. comparing GP vs hospital would cause bias with potentially more sick people in hospital cohort

Question 6

2 ways you can overcome confounding factors?

Answer 6

Direct or indirect standardisation

Question 7

Name 4 causes of information bias and explain them

Answer 7

1) Recall bias - change in story from person
2) Interviewer error e.g. leading questions
3) Measurement error e.g. error in measuring
4) Misclassification e.g. patients wrongly put in cohort e.g. disease exposure when they haven’t had it.

Question 8

Give and example of confounding factors

Answer 8

e.g. Age can confound death rate when comparing two groups

Question 9

What is a cross-sectional survey?

Answer 9

Descriptive and shows prevalence of something in society - already happened

Question 10

What is a cohort study? Pro/retro

Answer 10

Pro - looking forward so would need to expose certain people - need to be careful e.g. if this is a disease causing exposure

Retro - already had exposure now look at who has the disease.

Question 11

What is a Case-control study?

Answer 11

Compare specific cases of disease vs no disease and look back to see exposure

Question 12

What are odds, rate and risk ratio?

Answer 12

Odds - odds of having the disease, fraction of population with disease
Rate - incidence of disease over time
Risk - % with disease, given risk at one time

Question 13

For the three study designs above, which of rate, risk and odds ratio can you use?

Answer 13

Cohort - odds, rate, risk
Case-control - odds
Cross-sectional survey - Risk

Question 14

How do you define prevalence in an equation?

Answer 14

Prevalence = incidence x duration of disease

Question 15

Name 3 type of selection bias

Answer 15

Internal Validity
External Validity
Information bias (human error)