Definition Flashcards
Epidemiology
The study of the distribution and determinants of disease in a specified population, and application of this study to control health problems.
Exposure
factors associated with disease outcome
Outcome
condition that occurs following exposure
Descriptive epi
characterizing patterns in the distribution of population characteristics and disease according to person, place, time
Analytic Epi
focus on establishing cause and effect relationships between exposures and diseases
Primary prevention
reducing disease occurrence by minimizing exposure to risk factors
Secondary prevention
reduce number of people with the disease at any point in time by shortening the duration and/or severity of the disease
Prevalence
Proportion of individuals within a specified population that have existing disease at a specified time (%)
Incidence
Number of new cases occurring within a defined population at risk during a specific time interval. Incidence proportion (per 1,000 pop at risk), incidence rate (per 1,000 person-year at risk)
risk
the probability of an event occurring
When is OR a good estimate of RR
- disease frequency is low
- case exposure is representative of population cases derive from
- control ….
- person-time experience in control is similar to corresponding case
attributable risk
the number of disease cases attributed to exposure among those exposed.
e.g smoking accounts for 25.8 cases of CHD per 1,000 pop among smokers in the defined pop assuming causal relationship.
Chance
a random observation
Hypothesis Testing
Conducting a statistical test to make a decision on the compatibility between an observation and the null
Alpha
probability of INCORRECTLY rejecting a true null
Beta
probability of failure to reject a fall null
P value
probability observation is due to chance, at alpha
statistical power
probability of correctly rejecting a false Ho
Confidence Interval
a range of values that, at a given certainty (1-a), contain the true population parameter, assuming unbiased measures. (if CI includes null, then not statistically significant at alpha)
matching
process of selecting controls so that they are similar to cases on specific characteristics.
include individual and frequency matching
prognosis
how an individual is expected to progress after disease onset or intervention
primary prevention trail
examine whether an intervention reduces the risk of first disease occurrence.
secondary prevention trail
examine whether an intervention reduces symptoms, risk of recurrence or death in those with existing disease.
efficacy trail
the extent to which an intervention produces benefit under ideal circumstances
effectiveness trail
the extent to which an intervention produces benefit for reasonable percentage of participants in a more pragmatic setting.``
number needed to treat
NNT = 1/(placebo rate - intervention rate)
T/F: randomization affect statistical power
false. but it maximize comparability of intervention and control. balance distribution of extraneous factors.
