pre quiz 1 Flashcards
1
Q
count of prevalence
A
- just a number telling how many people have health outcome
- useful for rare conditions/short time spans
2
Q
prevalence proportion
A
- # cases present in pop at specified time/# people in pop at that time
- ranges from 0 (no one has disease) to 1 (everyone has disease)
- period: proportion of people w disease over length of specified tim e
- point: proportion with a disease at one specified time
3
Q
count of incidence
A
- number of new cases of a disease that have developed
- just new cases
4
Q
incidence proportion
A
- # new cases observed during some time period / # people at risk at start of time period
- assumes that we know what happens to everyone that was at start of time period
5
Q
A
6
Q
person-time
A
- sum of individual units of time that a person is at risk for developin disease have been followed
- contributes time to denominator of incidence rate until the study ends or they develop disease/die/lost to follow up
7
Q
incidence rate
A
- new cases of disease in a period of time / total person-time of population at risk
8
Q
relationship between incidence and prevalence
A
- continual addition of new cases (incidence) increases the prevalence, while death and/or cure decrease the prevalence
9
Q
what happens if incidence goes up and duration remains same
A
prevalence increases
10
Q
what happens if duration goes down and incidence remains the same
A
prevalence decreases
11
Q
case fatality
A
- measures death from a cause out of total people who have that disease
- # people who have died from a disease / # of people in pop at midyear w the disease
- mortality would be total # of people in pop at midyear in denominator
12
Q
prevalence ratios (ODDS)
A
- calculated same as relative risk/risk ratio
- generally used when disease is acute
- general use principle: when period at risk of developing the outcome extends over a considerable time (months to years)
