EPIDEMIOLOGY Flashcards
What is the role of epidemiology?
measurement of amount and distribution of disease, and natural history of disease
what is meant by prevalence?
number of disease cases in a population at a given time
how do you work out the prevalence?
number of affected individuals (cases) DIVIDED BY total number persons in population
what is meant by incidence?
number of new disease cases developing over a specific period of time in a defined population
how do you work out the incidence of disease?
number of new cases of a disease in a period DIVIDED BY number of individuals in the population at risk
what are the properties of an ideal index?
- clear, unambiguous, objective not subjective
- ideally correspond with clinically important stages of disease
- indicate treatment need
- within ability of examiners
- reproducible
- not time consuming
- acceptable to patients
what is the definition of a risk factor?
an environmental, behavioural or biological factor confirmed by temporal sequence, usually increasing the probability of a disease occurring, and, if absent or removed, reduces the probability
what must the concept of cause be distinguished from?
the concept of association
what is meant by cause in relation to disease?
external agent which results in disease in susceptible individuals
what are confounding variables?
A third variable that influences both the independent and dependent variable
