Measures Of Disease Frequency, Rates & Age-adjustment Flashcards
Incidence rate
Rate at which individuals develop a disease in a population. The number of new cases per unit of population over a specified period of time
Epidemiology
The study of the distribution and determinants of health and disease in human populations to enable health services to be planned rationally, disease surveillance to be carried out, and preventative and control programs to be implemented and evaluated
Person-time
The sum of individual follow-up times when they are at risk for the disease for all persons in the population. Accumulation of person time ends if that person 1. The event of interest, 2. Is no longer at risk of being observed for the event because she/he died from an unrelated cause or was lost to follow up
Cumulative incidence rate
The probability that an individual who is alive and free of disease will develop the disease during a specified period of time. Ex. The number of new cases per unit of population
Prevalence
The proportion of a population who have the disease at or during a specified time. Ex. It is the total number of new cases (new + old) existing in a population per unit of population
Mortality rate
A measure of the rate at which individuals in a population die during a specified period of time
Cause specific rates
Event rates for specific diseases; # of new events of a specified disease over a specified time period
Sex specific rates
Event rates within gender groupings
Race specific rates
Event rates within race groupings; number of new events in specified racial group
Case fatality rate
The proportion of people, among those who develop a disease, who then proceed to die from the disease
Proportional mortality
The proportion of deaths due to a specific cause
Crude rate
The proportion of individuals in a population who experienced the event (within the designate time period). Crude rates are pointless for making comparisons between populations if those populations differ in their age structure or if the distribution of men and women vary between the population
Age specific rates
Event rates within age groups (called age strata)
Age adjusted rates
Overall event rates that are adjusted for age sometimes called age-standardized rates; this is a hypothetical rate. It is the overall rate that we would estimate would occur if the population of interest had the same distribution as the standard population
