Term
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Definition
Upon, on top of
people or population
study of |
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Term
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Definition
| The study of distribution and determinants of health-related states and events in specified populations, and the application of this study to control health problems |
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Term
| Assumptions in epidemiology |
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Definition
-disease and ill health are not randomly distributed
-factors that determine this distribution are knowable and mostly modifiable
-modification = prevention and control of disease |
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Term
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Definition
D - concerned with distribution of disease by persons, places, and times. Without a hypothesis - hypothesis generating
A - Concerned with identifying disease determinants. Hypothesis testing. Casual inference is ultimate goal. |
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Term
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Definition
Hypothesis (the link)
Description
Analysis |
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Term
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Definition
Describes changing patterns of community health problems
Provides clues
Health services planning
Public health policy |
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Term
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Definition
Upon, on top of
people or population
study of |
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Term
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Definition
| prevent initial development of disease (risk factor reduction, immunization) |
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Term
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Definition
| Early detection of existing disease to reduce morbidity (screening for cancer, high blood pressure, etc.) |
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Term
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Definition
| Reduce the impact of acute worsening of disease |
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Term
| Epi Triad of infectious disease |
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Definition
Host - Susceptible
Agent - infectious or non-infectious
Environment - promotes exposure
Middle - vehicle
*or vector organism for indirect transmission |
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Term
| Triad of Non-infectious disease |
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Definition
Host - genetics, stress, psychological factors
Agent - behavior, diet, tobacco
Environment - neighborhood, parks, food outlets |
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Term
| Modes of disease transmission |
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Definition
1. escape of the agent from a source or reservoir
2. Conveyance
3. entry into host |
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Term
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Definition
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Term
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Definition
1. common vehicle
a. single exposure (potato salad)
b. multiple exposures
c. continuous exposure (telephone receiver)
2. vector (organism) |
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Term
| Definition of "carrier" status |
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Definition
| A host "harbors" the infectious agent but appears not infected and there are no detectable signs or symptoms |
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Term
| effect of non-apparent infection on disease control and disease statistics |
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Definition
| when the proportion with non-apparent infection is high, statistics will underestimate rates of infection and overstate overall disease severity |
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Term
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Definition
| habitual presence of a disease in a geographical area or population |
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Term
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Definition
| occurrence of a disease in a geographical area that is unusually frequent |
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Term
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Definition
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Term
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Definition
| the first disease case that appears in the population |
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Term
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Definition
| the disease case that brings the group or population to the attention of public health personnel |
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Term
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Definition
| time between infection and appearance of signs or symptoms |
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Term
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Definition
| resistance of group or population to invasion and spread of infectious agent based on the immunity of a high proportion of the group |
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Term
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Definition
from a single brief and essentially simultaneous source of exposure
- all of the cases usually result in a single incubation period |
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Term
| propagated ("progressive") |
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Definition
transmission from one individual to another
- epidemic extends over many incubation periods |
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Term
| general approach to outbreak investigation |
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Definition
- verify the diagnosis - perform clinical studies
- verify existence of epidemic - compare with past levels
- person, place and time - calc. attack rates |
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Term
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Definition
new cases rapidly occuring in a well-defined population over a short period of time
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total number of people at risk during that same period of time |
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Term
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Definition
*All times 100
new cases among contacts of initial cases occurring during a short period of time
---------------------------------------
(total number of people at risk during same period of time) - (initial cases) |
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Term
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Definition
1. a diseased state or symptom
2. the incidence of disease: the rate of sickness |
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Term
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Definition
| a ratio where time is included in the denominator |
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Term
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Definition
-special type of proportion that includes time
- represents the probability of disease in a defined population
- the basic measure of disease occurence |
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Term
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Definition
number of new cases of disease occurring during a defined period of time
-------------------------------------
number of people at risk for disease during defined period of time |
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Term
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Definition
all observed throughout a defined period of time
- closed cohort
- denominator = sum of all people at risk |
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Term
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Definition
all NOT observed for the full defined period of time
- person-time units
- denominator = sum of person observation time for each person at risk |
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Term
| cumulative incidence formula |
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Definition
number of new cases of disease occurring during a defined period of time
--------------------------------------
initial population at risk of the disease |
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Term
| incidence density formula |
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Definition
number of new cases of disease occurring during a defined period of time
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person-time at risk for the disease |
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Term
| Incidence rate based on group level data |
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Definition
number of new cases of disease occurring during a defined period of time
-----------------------------------------
number of people in population at risk at the mid-point of the period |
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Term
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Definition
International Statistical Classification of Diseases and related health problems
- used for coding and classifying mortality data from death certificates |
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Term
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Definition
International Statistical Classification of Diseases - Clinical Modification
- Used to code and classify disease morbidity data from inpatient and outpatient records |
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Term
| problems determining who goes into the numerator |
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Definition
1. what is the best case definition
2. detection (under or over diagnosis)
3. prevalent or incident (existing cases or new cases) |
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Term
| problems determining who goes into the denominator |
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Definition
1. under-counting of certain population subgroups
2. not everyone in the denominator is at risk for disease
3. population studied may have limited external applicability |
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Term
| Limitations of hospital data |
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Definition
1. admissions are selective
2. Hospital records are not designed for research
3. Populations at risk are not generally well defined |
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Term
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Definition
number of existing cases AT a point in time
-----------------------------------
number of people in the popualtion AT that point in time |
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Term
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Definition
Number of existing cases DURING a defined period of time
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number of people in the population DURING that defined period of time |
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Term
| Relationship between incidence and prevalence |
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Definition
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Term
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Definition
number of all new events during a period of time
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number of people at risk for these events during same period |
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Term
| Problems with crude rates |
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Definition
| Crude rates can obscure the fact that subgroups in the population at risk exhibit significant differences in risk. Thus, rates may not be comparable across populations unless there is adjustment for population-specific subgroup composition. |
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Term
| Why look at mortality quantitatively? |
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Definition
- can indicate disease severity and determine if treatment has become more effective over time
-serve as a surrogate for incidence when the disease is severe
- pinpoint difference in the risk of dying from a disease between population subgroups |
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Term
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Definition
number of people who die during a period of time
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size of population during midpoint of the period |
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Term
| all-cause annual mortality formula |
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Definition
total number of people who die from any cause during 1 year
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population at midpoint of that year |
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Term
| disease specific annual mortaity |
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Definition
number of people who die of a specific disease during 1 year
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population at risk at midpoint of that year |
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Term
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Definition
* proportion, so a %
number of people who die of a disease
--------------------------------
number of people with the disease |
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Term
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Definition
*proportion, so a %
number of people who die of a disease
-----------------------------
total deaths |
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Term
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Definition
1. age is associated with the disease or health state of interest
2. age distribution structure of the populations being compared are different |
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Term
| Direct method for age-adjustment |
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Definition
| compute the overall mortality rate that would be expected if each population had the same age structure as the standard population |
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Term
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Definition
- holds age constant
- gives a more accurate picture of differences in rates across populations |
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Term
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Definition
- fictional rates are calculated
- suppresses details of how subgroups differ across the variable used for adjustment |
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Term
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Definition
| - used when age group-specific rates are not available |
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Term
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Definition
| probability of death vs probability of survival |
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Term
| Case fatality rate formula |
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Definition
*rate, so a %
number of people who die of a disease
-------------------------------
number of people with the disease |
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Term
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Definition
- good index of severity of a short-term, acute disease
- can measure benefit of a new therapy |
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Term
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Definition
| percentage of people with a disease who are alive at the end of a specified time interval |
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Term
| 5-year survival rate formula |
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Definition
*rate, so a %
number of cases of the disease who are alive 5 years later
--------------------------------------------
number of cases of the disease |
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Term
| limitations of 5-year survival rate |
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Definition
- assumes the probability of surviving is equal throughout
- does not use actual observed survival
- cannot account for survival affect |
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Term
| creator of the first life table |
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Definition
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Term
| limitations of classic life tables |
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Definition
| - assumes the probability of surviving is equal throughout the year or fixed interval |
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Term
| Numerators in Kaplan-Meier life tables |
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Definition
- an event is instantaneous
- numerator = the number of people who died at that instant
- denominator = the number of people alive up to that instant, including those who died
- minus withdrawals that occurred before that instant |
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Term
| Kaplan-Meier life table assumptions |
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Definition
- no secular(temporal) changes in effectiveness of treatment or tendency toward survival over time
- censoring must be independent of the probability of survival |
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Term
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Definition
| the length of time that half of the study population survives |
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Term
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Definition
| the sum of the individual survival times divided by the total number of people in the study population |
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Term
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Definition
observed survival in people with the disease
-------------------------------------
expected survival without the disease |
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Term
| cumulative incidence in an open cohort or closed cohort with incomplete follow-up |
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Definition
number of cases of disease occurring during a defined period of time
-------------------------------------------------
initial population at risk of the disease |
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Term
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Definition
the probability of an event occurring
- difficult to measure over time
- applies to a population, not individuals
- values range from 0-1, unit-less
- also expressed as a %
- defined for a certain time period |
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Term
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Definition
- special form of proportion that includes a specification of time
- probability of disease in a defined population over time
- the basic measure of disease occurrence
- a risk in disguise
- the risk of acquiring a disease, and death from a disease is the best approx. by a measure of its incidence |
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Term
| Which measures of disease occurrence below gives you the most accurate information about risk? |
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Definition
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Term
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Definition
| Risk = (incidence rate * time) |
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Term
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Definition
| Risk = 1 - [exp ^-(rate * time)] |
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Term
Canons of Inductive Reasoning
- Method of Difference |
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Definition
| examines differences among groups for clues as to why disease rates or other health problems vary across groups |
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Term
Canons of Inductive Reasoning
- Method of Agreement |
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Definition
| looks for commonality in groups that manifest the same health problem |
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Term
Canons of Inductive Reasoning
- Method of Concomitant Variation |
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Definition
| traces how exposure to a hazard varies in relation to disease or other health problem |
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Term
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Definition
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Term
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Definition
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