Midterm Exam Flashcards
cumulative incidence per 1,000
(# of new cases)/(# of total persons at risk of developing the disease0 x 1,000
incidence rate per 1,000
(# of new cases)/(total person-years) x 1,000
prevalence per 1,000
(# of existing cases)/(total population) x 1,000
point prevalence
cases at a singular point in time (ex: do you have asthma right now?)
period prevalence
cases within a period of time (ex: have you had asthma in the past x years?)
relative risk
(cumulative incidence in exposed) / (cumulative incidence in unexposed) OR (incidence rate in exposed)/(incidence rate in unexposed)
cross-sectional studies are calculations of (prevalence/incidence)
prevalence
cohort studies are calculations of (prevalence/incidence)
incidence
as incidence increases, prevalence ____________
increases
as deaths/cures from a disease in a population increases, prevalence _______
decreases
prevalence of disease formula
a/(a+b)
prevalence of exposure formula
a/(a+c)
odds ratio formula
ad/bc
in what type of study is an odds ratio utilized?
case-control study
matched pairs odds ratios utilize (concordant pairs/discordant pairs)
discordant pairs
3 assumptions of when an odds ratio is a good approximation of risk
- a disease is rare
- controls are representative of total population
- cases are representative of all cases
matched pairs odds ratio formula
b/c
group matching can account for _______ variables
confounding
formula for prevalence
prevalence = (incidence) x (duration of disease)
formula for prevalence may only apply with the assumption that:
the population is in a steady state where (migration in = migration out)
incidence in exposed
a/(a+b)
incidence in non-exposed
c/(c+d)
