measuring health and disease Flashcards
Epidemiology
it is the study of how diseases and health conditions are distributed in a specified population and how they are controlled.
what is the epidemiological approach steps
1st step- is counting cases
2nd step- is dividing the number of cases by an appropriate denominator
3rd step- is comparing these rates over time for different groups of people
what is the prevalence and how is it calculated
prevalent cases are those who have the disease or health events in a population at a certain time
prevalence : number of people who have the disease at a specific time/ number of people at risk at a specific time
what is the incidence and how is it calculated
incidence represents the rate of occurrence of a specific disease or health event within a particular population at a specific period of time.
Incidence rates are calculated by dividing the number of new cases in a given time period /by the total population at risk during this period.
what is the difference between incidence and prevalence?
incidence cases are all new cases at a specific time whereas prevalence cases are all the cases at a specified time
what factors increase the rate of prevalence in a population?
1-prolongation of patients’ lives without a cure
2- in-migration of cases
3- out-migration of healthy people
4- in- migration of susceptible people
5- increase in incidence rate
6- longer duration of disease
7- improvement in diagnostics facilities
what factors decrease the rate of prevalence in a population?
1- shorter duration of disease
2- in-migration of healthy people
3- decrease in incidence rate
4- out-migration of cases
5- improved cure rates of cases
6- high case fatality
summarise prevalence
prevalence is a useful measure of disease burden
knowing about the prevalence of a specific disease can help us understands the demands on health services to manage this disease
prevalence changes when patients are cured or die
higher prevalence could mean a prolonged period without a cure or an increase in new cases or both
low prevalence could mean more people are dying without cure, lower new cases and/or rapid recovery
what is public health surveillance?
it is the continues systematic collection, analysis and interpretation of health-related data needed for the implementation, planning and evaluation of public health practice
what is a case definition
Case definitions usually consist of clinical criteria such as confirmatory laboratory tests and/or combinations of symptoms (subjective complaints), signs (objective physical findings) and other findings. Sometimes limitations on time, place and person can also be included particularly if the case definitions are being used in an outbreak of a disease.
