Summary Glossary of Terms An Introduction to Epidemiology for Health Professionals, ISBN: 9781441914972 Introduction To Epidemiology And Public Health (HNH24806)

Glossary assignment
Introduction to Epidemiology and Public Health

Definition in own
Synonyms Calculation Units
Concept Definition (source) words/ Additional questions Other comments
(if applicable) (if applicable) (if applicable)
give example

WEEK 1
1. Prevalence proportion (P) proportion of population calculates how much prevalence number of people with % or proportion What is the difference
that have the disease at people have the percentage disease at given point in between prevalence
a given point in time disease in a point in time / total number of proportion and incidence
time people in the population proportion?
at that time
-> how many cases there are
2. Incidence proportion (IP) or proportion of population calculates how many cumulative number of people who % or proportion at 1 point in time vs. how Proportion: is a
risk who develop the disease new cases of the Incidence, develop disease in many new cases occur in a special type of ratio in
in a specific time period disease accor in a Attack Rate, specific period of time / period of time. which everything or
period of time in the Experimental everyone in the
(new cases) number of people at risk
population and Control numerator is also
of getting the disease at counted in the
Event Rate the start of the period denominator. F.e:
number of people
who develop
disease / total
number of people in
the population =
between 0-1 or 0%
and 100%




3. Incidence rate (IR) rate at which new cases may be crude, specific incidence number of people who per What is the difference Rate: should contain
of a disease occurred (age-specific) or density develop disease in a 100.000/person between incidence proportion some measure of
divided by person-time standardised (direct specific time period / years or per and incidence rate? time, F.e: 60 km per
experience of the standardization) number of person-years 1000,10.000,etc. hour, 17/100.000 per
population when people were at risk -> incidence rates take year. Unlike a
of getting the disease perspective of what is proportion, it has no
happening from moment to upper limit.
moment vs. incidence
proportion takes in
perspective of what happens

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, over an accumulation of time.

4. Open cohort / dynamic can take new members All students in incident rate can be What is the difference
populations with time, people move campus calculated between an open and a
in and out of the area, closed population? Can you
numbers remain about think of examples for both?
the same, no follow-up
when leaving -> following all students that
are present on campus vs.
5. Closed populations based on fixed Members of this closed/fixed incidence proportion and following all students in this
membership, no one can course populations incidence rate can be course.
be added, but people calculated
On campus the people
may die/lost to follow-
change from day to day, in
up/etc, becomes smaller
the course there are no new
with time, everyone is
enrollments.
followed

WEEK 2
6. (Crude) mortality rate these rates describe For example, the rate Crude rates number of cases in a total Explain the difference
overall incidence or doesn’t take into population / person-time between crude and
death rate in a account: the reason for which the population standardised mortality rates
population without of death, the type of at risk has been observed
the disease, gender, Crude: raw numbers.
taking any other
age, ethnicity, etc. Standardized: considers other
features of the factors.
population into account

7. Direct standardisation involves calculating the To calculate, you need (1) What is the added value of
overall incidence or age-specific direct standardisation?
mortality rate that you disease/mortality rates in
the study population, and It can predict, it can put
would have expected to
(2) age distribution of the numbers in perspective. You
find in a ‘standard’
standard population. -> can compare numbers from
population, for example groups with standardized
if it had the same age- data.
specific rates as your
study population. First; age-specific
mortality rate * no. of
people in that age group
in the standard
population = no. of
events that you would
expect to see in the

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, standard population if it
had the same rates as
your study population.



Then; total no of events
expected / no. of people
in standard population =
standardised rate.



8. Indirect standardisation the actual number of this measure tells you SMR: To calculate, you need (1) What is the difference
deaths ‘observed’ in a how much more standardized age-distribution of the between direct and indirect
population is compared common death from mortality ratios study population, and (2) standardisation?
with the number of a specific disease is in age-specific disease rates
Direct standardisation: we
deaths that would have one group in in the standard
calculate the overall rate that
been ‘expected’ if the comparison to population. -> we would see in a standard
death rates in both another group. population if it had the same
populations had been age-specific rates of disease
the same First; age-specific rate in as our study population. In
standard population * no. contrast, Indirect
of people in that age standardization: we calculate
group in the study the number of cases we
would expect to see in our
population = no. of
study population if it had the
events you would expect
same age-specific rates of
to see in the study
disease as a standard
population if it had the population.
same rates as the
standard population.



Then; total no. of events
actually observed in study
population / no. of events
expected if study
population had had the
same rates as standard
population =
standardised mortality
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