Measuring Disease

Question 1

what is prevalence?

Answer 1

a measure of the frequency of existing cases in a population at a given time

Question 2

what is prevalence influenced by?

Answer 2

severity of illness, duration of illness and number of new cases

Question 3

how to calculate the prevalence?

Answer 3

-number of people with disease or condition at specific time divided by number of people in the population at risk at the specified time

Question 4

what is incidence?

Answer 4

rate of occurrence of new cases over a period of time in a specific population

Question 5

what is useful for assessing impact of acute conditions?

Answer 5

incidence

Question 6

incidence fraction?

Answer 6

-number of new events in a specified period divided by number of persons exposed to risk during this period (in person years)

Question 7

what is cumulative inc?

Answer 7

-number of people who develop the disease in a specified period divided by number of people at risk of getting the disease at the start of the period.

Question 8

what is case fatality?

Answer 8

number of deaths from diagnosed cases in a given period / number of diagnosed cases of the disease in the same period

Question 9

what are the 3 main functions used to compare disease occurrence?

Answer 9

• relative risk ratio
• attributable risk
• population attributable risk

Question 10

what is relative risk ratio?

Answer 10

-risk in exposed/risk in unexposed

Question 11

what is attributable risk?

Answer 11

(risk-exposed - risk-unexposed)/risk-exposed

Question 12

what is population attributable risk?

Answer 12

-(risk-total - risk-unexposed)/risk-total