3 Descriptive Epidemiology

Question 1

Prevalence

Answer 1

Number of people who have the disease at a certain point in time
Prevalence = existing cases / total population of interest (or at risk)

Question 2

Incidence

Answer 2

Number of new cases of the disease at a point in time.
Incidence = new cases / total population of interest (or at risk) minus existing cases

Question 3

Mortality

Answer 3

Number of deaths from a disease
Mortality = new deaths / total population of interest (or at risk)

Question 4

Years of Life Lost (YLLs) - also called Years of Potential Life Lost (YPLLs)

Answer 4

Years of life lost because of premature death. Remaining life expectancy is predicted and then the number of years lost is calculated.
YLLs = mortality × average remaining life expectancy

Question 5

Years Lived with Disability (YLDs)

Answer 5

Years of life lived with disability combined with the decided disability weight of that disability helps us determine the years of life this disability deprived an individual of.
YLDs = prevalence × disability weight

Question 6

Disability-Adjusted Life Years (DALYs)

Answer 6

YLL+YLD shows the total burden a disease or disability has on human life. Helps us understand what is most important to work towards solving/improving.
DALYS = YLLs + YLDs

Question 7

If I present you with the appropriate numbers for numerators and denominators and multipliers, be able to calculate the following measures:
Prevalence = existing cases / total population of interest (or at risk)
Incidence = new cases / total population of interest (or at risk) minus existing cases
Mortality = new deaths / total population of interest (or at risk)
YLLs = mortality × average remaining life expectancy
YLDs = prevalence × disability weight
DALYS = YLLs + YLDs

Answer 7

See notes for lecture 6

Question 8

What does the following picture imply about relationships amongst incidence, prevalence, and mortality (or, in a more optimistic scenario, recovery)?

Answer 8

Faucet tub and drain picture see notes in lecture 6

Question 9

If I present you with a graph or chart or table of health-related data, be able to …
Describe a pattern based on personal characteristics, such as differences by age, sex/gender, race/ethnicity, or other demographic identifiers
Describe a pattern based on place, such as differences by geographic location, state, country, urban/rural, etc
Describe a pattern based on time, such as increases or decreases over calendar time, seasonal cycles, etc

Answer 9

see lecture 6 descriptive epidemiology slides

Question 10

Describe a pattern based on personal characteristics,

Answer 10

such as differences by age, sex/gender, race/ethnicity, or other demographic identifiers
see reading notes prior to lecture 5

Question 11

Describe a pattern based on place,

Answer 11

such as differences by geographic location, state, country, urban/rural, etc

Question 12

Describe a pattern based on time,

Answer 12

such as increases or decreases over calendar time, seasonal cycles, etc