Epidemiologic Context and Measurements

Question 1

What is epidemiology

Answer 1

• Occurrence, distribution and determinants of disease in populations

Question 2

What is target population

Answer 2

• Large group from which study population is selected (sample)
• Target population must be well defined
• Uses inclusion and exclusion criteria

Question 3

What is population at risk

Answer 3

• All individuals who are susceptible to disease at onset of period

Excluded after develops the disease, can be reincluded after if disease free

Question 4

Formula point prevalence

Answer 4

o Proportion of people with disease at specific point of time
o (number of people with disease) / (number of people in population)

Question 5

Formula period prevalence

Answer 5

o Proportion of people with disease at any time during specified time period
o Includes existing cases of disease and new cases

Question 6

What is incidence

Answer 6

• New disease onsets per specified unit of population during specified period of time

Question 7

Incidence proportion formula

Answer 7

• Incidence proportion = Number of new cases within specified time / size of population at risk

Question 8

In incidence, size of population can be 2 things

Answer 8

Number of people exposed or person time