Block 1 Flashcards
1
Q
A
Stationary pyramid:
Low fertility & mortality
High life expectancy
Developed countries (Most even across age groups)
2
Q
A
Constrictive Pyramid:
Low fertility & mortality
High life expectancy
Well developed/rich countries
3
Q
A
Expansive pyramid:
Hight fertility & mortality rate
Low life expectancy
Developing countries
4
Q
Endemic
A
A base line of a disease that is normally seen in a population
5
Q
Hyperendemic
A
Persistent/high levels of a disease normally seen in a population
6
Q
Sporadic
A
A disease that occurs infrequently and irregularly in a population
7
Q
Holoendemic
A
Endemic in children but not adults
8
Q
Epidemic/outbreak
A
Epidemic: sudden increase in expected cases of a disease in a population (larger area)
Outbreak (ditto but for a smaller area)
9
Q
Cluster
A
Smaller groups of high cases in a specific place/time
10
Q
Pandemic
A
Global spread
11
Q
Endemic common source
A brief exposure period with 1 incubation period
A
Point source
12
Q
Endemic common source:
Multiple exposure points and incubation periods
A
Continuous
13
Q
Epidemic Common source:
Different exposure sources and times and different incubation times
A
Intermittent
14
Q
Propagated types
A
person-person
Vehicle-person
Vector-person
15
Q
Mixed source
A
Common source + person-person
16
Q
Outbreak analysis:
Description
Analytic
Control/follow-up
A
D: Confirm diagnosis/existence
A: Develop hypothesis/test
C: Control/public health measures
17
Q
Fertility rate
A
(Women of childbearing age)
/(population)
18
Q
Incidence rate/Attack Rate
A
(# New cases)/
(Population @ risk) x1000
19
Q
Prevalence
A
(# All cases)/
(Total population) x1000
20
Q
Primordial
A
Preventative law (tobacco tax laws)
21
Q
Primary
A
Control risks (Vaccines)
22
Q
Secondary
A
Early detection (screening)
23
Q
Tertiary
A
Reduce complications (therapy/treatment)
24
Q
YPLL
A
(life expectancy) -
(age @ death)
25
Proportionate mortality
(Deaths associated to the disease) /
(All deaths)
26
Crude mortality
All death/ all population
27
Cause-specific mortality
(death ass to disease within a 1yr) / (total population mid year)
28
Case fatality
(Death ass with disease @ specific time) /
(Population @ the same time)
29
Neonate mortality
(Death after 28 days)/
(live births)
30
Post natal mortality
(death between 28-365 days)/
(live births)
31
Infant mortality
Neonate mortality + infant mortality
32
Mean incubation period
Peak - exposure (day 1)
33
Birth rate
live births / total population
34
Endemic
amount of a particular disease that is usually present in a community
35
Hyperendemic
Refers to persistent, high levels of disease occurrence
36
Sporadic
disease that occurs infrequently and irregularly
37
Holoendemic
endemic in most of the children in a population, with the adults in the same population being less often affected
38
Epidemic/outbreaks
increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area
Outbreak: same definition of epidemic, but is often used for a more limited geographic area
39
Cluster
aggregation of cases grouped in place and time that are suspected to be greater than the number expected, even though the expected number may not be known
40
Pandemic
epidemic that has spread over several countries or continents, usually affecting a large number of people
41
A multinational outbreak of influenza
a) Hypoendemic
b) Endemic
c) Epidemic
d) Hyperendemic
e) Pandemic
f) Holoendemic
Pandemic
42
The long-term, relatively constant rate of occurrence of colorectal cancer in U.S. Women
a) Hypoendemic
b) Endemic
c) Epidemic
d) Hyperendemic
e) Pandemic
f) Holoendemic
Endemic
43
44
Epidemics can be classified according to the manner of spread through a population
Common-source (point, continuous, intermittent)
Propagated
Mixed
Other
45
Common-source
It is one in which a group of persons are all exposed to an infectious agent or a toxin from the same source.
46
Point-source
If the group is exposed over a relatively brief period, so that everyone who becomes ill does so within one incubation period, then the common-source outbreak is further classified as a point-source outbreak
47
Continuous common source outbreak
the range of exposures and range of incubation periods tend to flatten and widen the peaks of the epidemic curve.
48
Intermittent common-source outbreak
outbreak often has a pattern reflecting the intermittent nature of the exposure
49
Propagated source
Results from transmission from one person to another:
person-to-person contact (syphilis)
vehicle-borne (Hepatitis B – use of needles)
vector-borne (mosquitoes)
cases occur over more than one incubation period
The epidemic usually declines after a few generations
50
Mixed source
epidemics have features of both common-source epidemics and propagated epidemics
The pattern of a common-source outbreak followed by secondary person-to-person spread
51
How do you know when a potential outbreak is occurring?
Regular reviews of surveillance data from lab-confirmed reports or clinical reports of notifiable diseases to alter you of unusual increase in disease
52
Outbreak alters
Health care providers
Public or community
Press/ TV
Public health surveillance
53
If an outbreak is now starting focus on _____ & if the outbreak is nearly over identify the source to ________ outbreaks
control & prevent future outbreaks
54
4 Goals of an outbreak investigation
Containing the infection
Protecting susceptible persons
Actively search for new cases
Case management
55
phases of an outbreak investigation
Descriptive --> Analytic study -->Control/follow up
56
Descriptive phase
Become "experts" about the disease
- Confirm the existence of an outbreak
- Confirm the diagnosis
- Assess patients & establish a case definition
- Orient the data in person, place, and time
57
Analytic study
- Develop a hypothesis & test it
- Analyze the data & compare it with other studies
- Formulate a conclusion or revise a hypothesis
58
Control & follow-up
- Implement control and preventative measures
- Write and disseminate a report
- Evaluate the preventative measures!!!
59
Confirming the existence of an outbreak
compare observed with the expected number of cases and sources of data:
Surveillance data
Hospital records
Sentinel sites
Prescriptions/pharmacy stocks
60
Case Classification Levels
Confirmed (clinical symptoms & labs)
Probable (Clinical symptoms/epidemiological link)
Suspect (compatible symptoms/possible epi link)
61
Challenges of case findings
- Not all cases are confirmed
- Some infected persons might not seek medical attention
- The exposed population might not be well defined
62
Functions of descriptive epidemiology
-Helps characterize an outbreak by providing info about the who, what, when, & where
- ID's the pop at risk
- Give clues about the agent, source, or mode of transmission
- Give info about the leading prevention and control measures
- Familiarize the investigator with the data
63
Epidemic curve
An epidemic curve is a graphical depiction of an unusual increase in the number of cases of disease in a population
Y-axis: Number of cases of illness
X-axis: Date or time of illness onset
64
Propagated epidemic
Series of peaks with one incubation period apart
Aka person-person spread
65
Epi Curve- Point source
Curve with a peak and steeper upward slope rather than downward slope
66
Epi curve- common source
Continuous exposure
Persistent over a period of time. In this instance the peak remains for a longer period, it will plateau. The top left figure is an example.
67
Epi curve- common source
Intermittent exposure
Breaks between peaks
68
Epi-curve mixed
not cause by one common source, but rather a propagated or progressive source.
The shape of the curve usually contains a series of peaks, which are usually about one incubation apart.
69
Incubation period
Median incubation period = Peak - Exposure
70
Cohort study
for small, well defined outbreaks, investigates all persons
71
Case control study
larger outbreaks, investigates a sample of cases and controls
72
Morbidity
Measures frequency of illness within populations ALIVE
73
Prevalence
Frequency of all current cases
74
Incidence
number of new cases
75
Attack rate
incidence during a limited time such as during an epidemic
76
Mortality
Measures frequency of deaths in given time, place and population
77
Crude death rate
measures number of deaths in a given population over a specified time
78
Disease specific death rates
measures number of deaths due to a specific disease in a given population over a specified time
79
Natality
Birthrates or fertility rates
80
Case investigations
Detailed report of one patient, usually for
-Rare diseases
-Unusual cases of common diseases
-Diseases nearing elimination (Measles, Rubella, Leprosy)
81
Population based disease registery
contains records for people diagnosed with a specific type of disease who reside within a defined geographic region
82
Hospital based disease registry
contains data on all the patients with a specific type of disease diagnosed and treated at that hospital
83
Exposure based disease registry
contain information about individuals at high risk of disease due to exposure to hazardous substances in the workplace or environment
84
Sentinel reports
-From selected representative reporting sites
-For monitoring key health indicators
-Provides early warning signals
-Can be for general or specific populations
85
Surveys
- Monitor changing prevalence over time if repeated periodically
- can be costly
-Good for assessment of Knowledge Attitude, Behavior, & Practice
86
Rates
Tell us how fast the disease is occurring in a population
87
Proportions
Tell us what fraction of the population is affected
88
Birth Rate
Rate of live births in a population during a time period (usually the calendar year).
Live births
Simple formula: ------------------- x 1,000
Population
89
Fertility Rate
Rate of live births among women of childbearing age (ages 15-44) in a population during a time period (usually the calendar year).
Live births X 1,000
Simple formula: ------------------
Women of childbearing age
90
Incidence
new cases in at risk population
useful in cohort studies
mainly for acute conditions or diseases
91
Prevalence
of all cases in the entire population
Useful in the study of the burden or chronic disease
92
Factors affecting prevalence
Duration of disease (longer = higher prev)
Fatality rates (higher = lower prev)
Occurrence of new cases
In-migration of cases vs healthy people
Out-migration of cases vs healthy people
Susceptible cases vs cure rate of cases
Diagnostic facilities
93
Incidence
Incidence =
No. of new cases of a disease occurring in the population at risk during a specified period of time
-------------------------------------------------------------- (1000)
No. of persons who are at risk of developing the disease during that period of time
94
Prevalence
prevalence=
No. of all cases of a disease present in the population at a specified period of time
-------------------------------------------------------(1000)
No. of persons in the population at that specified time
95
In a city with a population of 1,000,000, 10,000 individuals have HIV disease. There are 1000 new cases of HIV disease and 200 deaths each year from the disease. There are 2500 deaths per year from all causes. Assuming no net emigration from or immigration to the city, the incidence of HIV disease in this city is given by which of the following?
200/1,000,000
800/1,000,000
1000/990,000
2500/1,000,000
10,000/990,000
10,000/1,000,000
incidence =
1000/(1,000,000 -10,000)
1000/990,000
96
A state with a population of 4,000,000 contains 20,000 people who have disease A, a fatal neurodegenerative condition. There are 7,000 new cases of the disease a year and 1,000 deaths attributable to disease A. There are 40,000 deaths per year from all causes. What is the incidence of the disease?
A. 1000/4,000,000
B. 6000/4,000,000
C. 7000/4,000,000
D. 20,000/4,000,000
E. 40,000/4,000,000
Incidence=
7,000/(4,000,000 - 20,000 =3,980,000 round up)
7000/4,000,000
97
Recently, investigators working with the health department of Elmira county collected the following cancer statistics. As of December 31, 2000, 100 cases of prostate cancer were counted, 20 of which were diagnosed since January 1, 2000. As of the same date, the adult population of the county was 10,000, 60% of whom were female. Based on the statistics provided what is the prevalence of prostate cancer in Elmira County in the year 2000?
5 per 1000
10 per 1000
15 per 1000
20 per 1000
25 per 1000
Prevelance=
10,000 (60% female, 40% male)
0.4 * 10,000 =4,000
100/4000* 1000 =25 per 1000
98
Population of the city of Atlantis on March 30, 2003 was 183,000. 26 new cases of active TB occurred between January 1 and June 30, 2003. According to the city register on June 30, 2003 there were 264 active TB cases.
What is the incidence rate of active cases of TB for the 6-month period ?
7 per 100,000 population
14 per 100,000 population
26 per 100,000 population
28 per 100,000 population
130 per 100,000 population
Incidence =
26/(183,000-264)
26/182,736 (1000) = 0.14 per 100,000
99
in an outbreak of gastroenteritis with 50 cases among a population at risk of 2500, the attack rate of disease is
AR= 50/2500 = 0.02 or 2/100 0r 20/1000
100
After a dinner attended by 100 people, 12 individuals become ill. All 100 people are interviewed about their food consumption at the dinner. The interviews show that 8 of the 12 people who are ill and 25 of the 88 who are healthy ate fish.
Number of sick people
who ate a particular food
Attack Rate = --------------------------------------
Total number of people
who ate this food
AR= 8/33 =0.24*
101
Secondary attack rate
a measure of the frequency of new cases among contacts of known cases
new cases among contacts of primary
cases during the period
Sec. AR = ----------------------------
total number of contacts during the
same period
102
At a day-care center, 10 of the 50 children develop acute viral conjunctivitis (pink eye) within a 1-week period. Another 30 of the children also develop pink eye in the following 2 weeks.
Q1. What is the first attack rate of conjunctivitis at this day-care center?
Q2. What is the secondary attack rate of conjunctivitis at this day-care center?
10/50 = 0.2 0r 20%
30/40 = 0.75 or 75%
103
A new vaccine is introduced, which effectively prevents the development of Disease X. Over time, what will be the effect upon the incidence of Disease X.
Incidence will increase
Incidence will decrease
Incidence will stay the same
Incidence will decrease then increase
Incidence will decrease prevalence will not change
104
An experimental drug that selectively binds malignant lymphocytes has been shown to significantly prolong survival in patients with stage 3 and stage 4 chronic lymphocytic leukemia (CLL). If this new drug were widely used, what changes in the incidence and prevalence of CLL would be expected?
Incidence will decrease, prevalence will decrease
Incidence will not change, prevalence will increase
Incidence will increase, prevalence will not change
Incidence will not change, prevalence will not change
Incidence will decrease, prevalence will increase
Incidence won't change but prevalence will actually increase.
105
Crude mortality rates
Crude mortality=
All deaths during a yr
----------------------------------
Population at mid yr
106
Cause-specific mortality rate
Deaths assigned to the specific disease during a yr
---------------------------------------------------------------------
Population at a yr
107
Case fatality rate
# of cases of the disease in the same time period
of deaths due to the disease in a specific time period
----------------------------------------------------------------------
# of cases of the disease in the same time period
108
Proportionate mortality ratio
Deaths assigned to the disease in a certain yr
------------------------------------------------------------------
Total death in the population in the same yr
109
Maternal mortality rate
number of maternal deaths in a given area in a yr
------------------------------------------------------------------(10)
Number of live births in the same area during same yr
110
An outbreak of illness from Infection X disease took place in the United States between July and October, 2001. Two of 21 patients with Infection X disease died. This measurement of disease is best described as
Case fatality
Crude mortality
Cause specific mortality
Incidence
Prevalence
Case fatality
111
YOPLL
Life expectancy - age at death
112
There are 250 deaths per year in a population of 100,000. What does this represent?
Adult mortality rate
Cause-specific mortality rate
Case fatality rate
Crude mortality rate
Proportionate mortality rate
Crude mortality rate
113
The country of Badheart had a population of 100,000,000 in 1995. There were 10,000,000 deaths reported in that same year, of which 5,000,000 were from heart disease. All together, 20,000,000 citizens of Badheart had heart disease in 1995. What was the crude death rate in Badheart in 1995?
50 per 1000 population
250 per 1000 population
500 per 1000 population
200 per 1000 population
100 per 1000 population
crude death=
10,000,000/100,000,000 (1000)
100 per 1000 population
114
In an Asian country with a population of 6 million people, 60,000 deaths occurred during the year ending December 31, 1995. These included 30,000 deaths from cholera in 100,000 people who were sick with cholera.
What was the crude mortality rate in 1995?
What was the cause-specific mortality rate from cholera in 1995?
What was the case-fatality rate from cholera in 1995?
What was proportionate mortality from cholera in 1995?
Crude death
= 60,000/6,000,000 = 0.01 *1000 =10 per 1000
Cause-spec
= 30,000/100,000 = 0.03*1000 =30 per 1000
Prop death
= 30,000/60,000 = 500 per 1000
115
Neonatal mortality rate
Infant deaths prior to day 28
-------------------------------------- X 1,000
Live births
116
Post neonatal mortality rate
Infant deaths from day 28 through day 365
--------------------------------------------------------X 1,000
Live births
117
Infant mortality rate
neonatal mortality rate + post-neonatal mortality rate
118
Primary prevention
denotes an action taken to prevent the development of a disease in a person who is well
and does not (yet) have the disease in question.
EX. Immunization
119
Secondary prevention
involves identifying people in whom a disease process has already begun but who have not yet developed clinical signs and symptoms
of the illness
EX. Screening
120
Tertiary prevention
denotes preventing complications in those who have already developed signs and symptoms of an illness and have been diagnosed (i.e., people
who are in the clinical phase of their illness)
EX. Treatment/therapy
121
Herd immunity
defined as the resistance of a group
of people to an attack by a disease to which a large proportion of the members of the group are immune. If a large percentage of the population is immune, the entire population is likely to be protected, not just those who are immune
122
AR
Number of people at risk in whom
a certain illness develops
----------------------------------------------------
Total number of people at risk
123
Endemic means that a disease:
a. Occurs clearly in excess of normal
expectancy
b. Is habitually present in human populations
c. Affects a large number of countries
simultaneously
d. Exhibits a seasonal pattern
e. Is prevalent among animals
b. Is habitually present in human populations
124
