Week 1 readings summary

Question 1

what is epidemiology?

Answer 1

WHO - the study of the distribution and determinants of health-related states or events in specified populations and the application of those study to control of health problems

Question 2

What are the main types of studies?

Answer 2

case reports/case series
correlational
cross sectional
case control
cohort
experimental m

Question 3

What is a case series study?

Answer 3

describes experience of single patent or group with similar diagnosis

Question 4

What is a correlational study?

Answer 4

characteristics of entire populations are used to describe frequency of health-related outcomes in relation to some factors relevant to the research Q

Question 5

What is a cross sectional study?

Answer 5

describes prevalence of health-related outcome in representative samples and relate to personal/demographic characteristics

Question 6

What is a case control study?

Answer 6

occurrence of possible cause compared between people known to have the disease (the cases) and reference group who do not (controls)

Question 7

What is a cohort study?

Answer 7

begin with a group of people free of disease and determine exposure to suspected risk factor

Question 8

What is an experimental study?

Answer 8

Involves an intervention to change a variable in one or more groups of people and measure effect of outcome

Question 9

What are the measures of health related outcomes?

Answer 9

prevalence
incidence
mortality
morbidity
life expectancy
population of attributable risk

Question 10

what is prevalence?

Answer 10

No of people in the population at risk at a specific time

Question 11

what is incidence?

Answer 11

sum of period of time for which each person in population at risk

Question 12

what is population attributable fraction (PAF)?

Answer 12

Estimates the incidence of a disease in a population that can be attributed to exposure to a particular risk factor

It reflects not only the strength of the risk associated with an exposure, but also its prevalence

Question 13

What is the relevance of PAF in the context of physical activity and mortality?

Answer 13

Physical inactivity has a moderate risk and high prevalence so the PAF for physical activity and mortality is high and greater than many traditional health risk factors

Question 14

How to measure PA

Answer 14

questionnaire

motion sensors e.g. accelerometer or pedometer

doubly labelled water technique

Question 15

What is doubly labelled water technique?

Answer 15

Non intrusive method for measuring total energy expenditure in free-living situations

Objective and more accurate than questionnaires

Expensive

Cannot distinguish between different rate of energy

Question 16

How to measure fitness

Answer 16

sub max tests

max tests

Question 17

What are the 4 types of error?

Answer 17

Type 1: rejecting null hypothesis when true

Type 2: accepting null hypothesis when false

random error

bias error

Question 18

What are the sources of random error?

Answer 18

biological variation
sampling error
measurement error

Question 19

how can we reduce random errors?

Answer 19

precise measurements

increasing sample size

Question 20

What are 2 types of bias error?

Answer 20

selection bias

measurement bias

Question 21

what is selection bias?

Answer 21

Arises when characteristics of people selected to participate in study differ systematically from those people who are not selected

Healthy worker effect - people in employment have to be healthy to do the job, those who are ill are often excluded

Question 22

what is measurement bias?

Answer 22

Recall bias: Issues around human memory and recall

Under/over reporting

Question 23

what criteria is used to assess whether epidemiological evidence is sufficient to conclude that a risk factor is casual?

Answer 23

appropriately sequenced
plausibility
consistency
strength
dose-response
reversibility