Intro to Epidemiology

Question 1

epidemology is:

Answer 1

the study of how disease is distributed in populations and factors that influence of determine this distribution

Question 2

what are the goals of epidemiology?

Answer 2

• identify causes and risk factors
• determine extent of disease
• study the natural history of disease
• evaluate preventive and therapeutic interventions
• provide the foundation for public policy discussions

Question 3

define incidence:

Answer 3

the number of new cases occurring in a particular time period

Question 4

define incidence rate

Answer 4

the ratio of new cases over a period of time to the total people at risk

= (#new cases)/(total # at risk) per unit time

Question 5

define prevalence, point and period:

Answer 5

the number of people affected by a disease at a particular time (point prevalence) or time period (period prevalence)

Question 6

define prevalence rate

Answer 6

ratio of the number of people with a disease to the total number of people at risk at a particular time or time period

= (# people with a disease) / (total # at a risk)

Question 7

define attack rate

Answer 7

the ratio of number contracting a disease to the total number at risk
-expressed as a percent

= (# contracting a disease)/(total # at risk (exposed)) x100

Question 8

when do you use attack rate?

Answer 8

• variation of incidence used when looking at a specific short term risk or exposure

Question 9

define mortality

Answer 9

the number of deaths

Question 10

define mortality rate

Answer 10

ratio of number of people dying over a period of time to the total number at risk

= total # deaths / total # at risk (per unit time)

• can be overall or specific to a cause

Question 11

define case fatality rate (CFR)

Answer 11

ratio of the number of people dying in a particular episode of a disease to the total number of episodes of the disease expressed as a percentage

= (number of people dying in an episode) / (total # of episodes of a disease) x100

-generally used to give probability of a death from a severe acute illness ex. pneumonia, meningitis, brain aneurysm

Question 12

describe the relationship between incidence and prevalence

Answer 12

the epidemiologist’s bathtub

Question 13

what effect do preventive measures have on prevalence and incidence?

Answer 13

usually decrease incidence and prevalence

Question 14

what effect does the treatment of an illness that speeds recovery have on prevalence and incidence?

Answer 14

usually will decrease prevalence and does not directly change incidence

Question 15

what effect does a treatment of an illness that delays or decreases death have on prevalence and incidence?

Answer 15

it will increase prevalence but does not directly change incidence