Unit 07: Disease Frequency and Measures of Association (Part 1)

Question 1

What is Morbidity?

Answer 1

refers to a diseased state and often considers the burden of disease, such as sickness or impairment.

Question 2

What is Mortality?

Answer 2

refers to death.

Question 3

What is count?

Answer 3

the number of something (ex. 150 POPM3240 students)

Question 4

What are ratios?

Answer 4

A dimensionless, unit-less comparison of one count to another (e.g., 1:4)

Question 5

what are Proportions?

Answer 5

Ratio where number is included in the denominator (e.g., 1/100, 27%, 0.55)

Question 6

What are Risks? (relative to statistics)

Answer 6

Proportions that express the probability that something will occur (e.g., 1/100, 27%, 0.55)

Question 7

What are Rates?

Answer 7

Expresses the occurrence of an event or outcome in a defined population in a specified period of time; can be considered a measure of “speed”

Question 8

Because the incidence rate is a measure of events (i.e., transition from a nondiseased to a diseased state), the incidence rate is a measure of…

Answer 8

Risk

Question 9

What is a cumulative incidence proportion?

Answer 9

period of time during which all of the individuals in the population are considered to be at risk for the outcome

Question 10

What is the attack rate?

Answer 10

• the number of people exposed to risk factor who became ill, divided by the number of people who were exposed to that risk factor.
• not truly a rate but a proportion.

Question 11

What is Prevalence?

Answer 11

the number of affected persons present in the population at a specific time divided by the number of persons in the population at that time (what proportion of the population is affected by the disease at that time?)

Question 12

What is Point prevalence?

Answer 12

Prevalence of the disease at a certain point in time

Question 13

What is Period prevalence?

Answer 13

How many people have had the disease at any point during a certain time period?

Question 14

What are some problems with Incidence and Prevalence Measurements?

Answer 14

• Problems With Numerators (defining it, etc.)
• Problems With Denominators (defining it, etc.)
• Problems With Hospital Data (hospital admissions are selective, etc.)

Question 15

What is the Geographic Information System?

Answer 15

• One approach to examining geographic or spatial differences in the distribution of cases, whether incidence or prevalence, is to plot the cases on a map.
• uses a variety of information on the geographic distribution of disease and how it is related to the environment that the people live in, and subsequently identifies clusters of diseases

Question 16

What is Incidence risk (cumulative incidence)?

Answer 16

the proportion of unaffected individuals (those who do not have the disease or outcome of interest) who, on average, develop the disease/outcome over a specific time period.

Question 17

What is Crude risk?

Answer 17

the “number developing any disease (for morbidity) or dying (mortality) within the specified period of time” divided by the “number at risk minus half the withdrawals” from the study.

Question 18

What is Crude rate?

Answer 18

the “number developing any disease (for morbidity) or dying (mortality) within the specified period of time” divided by the “average number at risk multiplied by the internal time component” of the study. The third formula is cause-specific.

Question 19

What is Cause-specific mortality rate?

Answer 19

the “number dying of a specific disease within the specified period of time” divided by the “average number at risk multiplied by the internal time component” of the study.

Question 20

What is Case fatality “rate”?

Answer 20

used to measure mortality of a particular disease, often an acute one.