KONSEP DASAR kewirausahaan EPIDEMIOLOGI (1)
KONSEP DASAR
EPIDEMIOLOGI
Vitri Widyaningsih
OUTLINE
Definisi dan Konsep Dasar Epidemiologi
Ruang Lingkup Epidemiologi
Konsep Dasar Timbulnya Penyakit
Penemuan Penyakit secara Screening
Definisi dan Konsep Dasar dalam
Epidemiologi
Definitions
Study Design
Measures of Disease Frequency
Measures of Association
What is Epidemiology?
Definitions
Epidemiology is the study of how disease is
distributed in populations and the factors that
determine that distribution (Gordis, 2013)
The science concerned with the study of the
factors determining and influencing the
frequency and distribution of disease, injury,
and other health-related events and their
causes in a defined human population. Also,
the sum of knowledge gained in such a study.
(Dorland, 2007)
STUDY DESIGN
Descriptive
Analytic
Examining the distribution of
a disease in a population,
and observing the basic
features of its distribution
in terms of time, place, and
person.
Testing a specific hypothesis
about the relationship of a
disease to a putative
cause, by conducting an
epidemiologic study that
relates the exposure of
interest to the disease of
interest.
Typical study design:
community health survey
(approximate synonyms cross-sectional study,
descriptive study)
Typical study designs:
cohort, case-control,
experimental
Epidemiologic Study Designs
Measure of Disease Frequency
1.
2.
Cumulative Incidence (Incidence, Risk, I, R)=
Number of new case over a time period
Population at risk at the beginning
- Indicates the risk for the disease to occur in population at risk over a
time period. Value from 0 to 1.
Incidence Density (Incidence Rate, ID, IR)=
Number of new case over a time period
Person time at risk
Indicates the velocity (speed) of the disease to occur in population over a
time period. Value from 0 to infinity
3.
Prevalence (Point Prevalence):
Number of new and old cases at a point of time
Population
Indicates burden of disease. Value from 0 to 1.
Levels of Disease Occurence
Sporadic level: occasional cases occurring at
irregular intervals
Endemic level: persistent occurrence with
moderate to high level
Epidemic or outbreak: occurrence clearly in
excess of the expected level for a given time period
Pandemic: epidemic spread over several countries
or continents, affecting a large number of people
Attack rate:
# cases of disease that develop during
________defined period_______
# in pop. at risk at start of period
(usually used for infectious disease outbreaks)
Measures of Disease Frequency
Measures of Disease Frequency
Measures of Disease Frequency
Measures of Disease Association
The chances of something happening can be
expressed as a risk or as an odds:
PROPORTION
RISK = the chances of something happening
the chances of all things happening
RATIO
ODDS= the chances of something happening
the chances of it not happening
MEASURES OF DISEASE ASSOCIATION (2)
The relative risk is a ratio of two risks.
Assume that among the 100 people at risk, 50 are men
and 50 women. If 15 men and 5 women develop
influenza, then the relative risk of developing influenza
in men, as compared with women, is:
Risk in men = 15/50
divided by
Risk in women = 5/50
15/50 ÷ 5/50 = 3.0
(Note that from the way the question was put, the two
risks are cumulative incidence rates.)
Measures of Disease Association (3)
The odds ratio is a ratio of two odds
The odds in men = 15/35
divided by
The odds in women = 5/35
15/35 ÷ 5/45 = 3.9
We conclude that the odds of men getting influenza
over the year are 3.9 times as high as the odds of
women getting influenza.
Thought question: note that the odds ratio in this
example (3.9) is larger than the relative risk (3.0).
Is this always the case? Is this important?
Ruang Lingkup Epidemiologi
Use of Epidemiology
Issues in Epidemiology
- Bias
- Confounding
- Hill’s Causal Criteria
Use of Epidemiology
Causation
Natural History
Description of
Health Status
Evaluation of Intervention
Konsep Dasar Timbulnya
Penyakit
Trias Bloom (Konsep Keseimbangan)
Natural History of Disease
The Basic Triad Of Descriptive Epidemiology
TIME
PLACE
PERSON
Description of Disease Distribution
in the Population
Disease affects
mostly people under
five years of age
Disease affects
people living
alongside the river
Disease reaches its
peak in frequency in
Week 6
The Basic Triad Of Analytic Epidemiology
HOST
AGENT
ENVIRONMENT
Factors Influencing Disease
Transmission
Agent
Environment
• Infectivity
• Weather
• Pathogenicity
• Housing
• Virulence
• Geography
• Immunogenicity
• Occupational setting
• Antigenic stability
• Air quality
• Survival
• Food
Host
• Age
• Sex
• Genotype
• Behaviour
• Nutritional status
• Health status
Natural History of Disease
Timeline of Infectiousness
Dynamics of
infectiousness
Latent
period
Infectious
period
Non-infectious
Susceptible
Time
Dynamics of
disease
Incubation
period
Symptomatic
period
Non-diseased
Susceptible
Time
Screening
Definition
Screening and Surveillance Difference
Definition
Examination of whole populations aims to
detect those at risk of a specific disorder or
condition who are likely to benefit from further
investigations and possibly treatment or action
to prevent the disorder or condition or its
consequences.
Surveillance involves investigating the
distribution and possible causes of diseases
and conditions within the population.
Active
Surveillance (based on active case finding)
Passive Surveillance (based on reporting)
REFRESH YOUR KNOWLEDGE
Pada 120 siswa SMP pada 1 januari dilakukan
screening anemia. Pada 120 siswa, 30 siswa (1
januari 2005) didiagnosa anemia. Pada 31
desember di skrining ulang, didapatkan 10 orang
lagi yg membutuhkan pengobatan. Angka
insidensi :
a. 10/90
b. 30/90
c. 10/120
d. 30/120
e. 40/120
Pada suatu wilayah kerja, diketahui jumlah karyawan
laki-laki yang menderita HIV pada tanggal 1 Januari
2012 sebanyak 50 dari 1000 orang. Pada tanggal 1
Januari 2013 terdapat 62 kasus dari 1000 orang
termasuk 50 orang tang terdeteksi sebelumnya.
Berapa prevalensi HIV pada tanggal 1 Januari
2013?
a. 5%
b. 6,2%
c. 1,2%
d. 50%
e. 62%
Sebuah penelitian ingin mencari risiko hipertensi pada PNS.
Didapatkan data sebagai berikut:
Dari data diatas, nilai yang
digunakan untuk menentukan
kekuatan hubungan antar
variable adalah?
a) Nilai p
b) Proporsi
c) Frekuensi
d) Ratio Odds
e) Interval kepercayaan
Dari data diatas, risiko mengalami hipertensi tertinggi
terdapat pada golongan ?
Thank You
Questions?
EPIDEMIOLOGI
Vitri Widyaningsih
OUTLINE
Definisi dan Konsep Dasar Epidemiologi
Ruang Lingkup Epidemiologi
Konsep Dasar Timbulnya Penyakit
Penemuan Penyakit secara Screening
Definisi dan Konsep Dasar dalam
Epidemiologi
Definitions
Study Design
Measures of Disease Frequency
Measures of Association
What is Epidemiology?
Definitions
Epidemiology is the study of how disease is
distributed in populations and the factors that
determine that distribution (Gordis, 2013)
The science concerned with the study of the
factors determining and influencing the
frequency and distribution of disease, injury,
and other health-related events and their
causes in a defined human population. Also,
the sum of knowledge gained in such a study.
(Dorland, 2007)
STUDY DESIGN
Descriptive
Analytic
Examining the distribution of
a disease in a population,
and observing the basic
features of its distribution
in terms of time, place, and
person.
Testing a specific hypothesis
about the relationship of a
disease to a putative
cause, by conducting an
epidemiologic study that
relates the exposure of
interest to the disease of
interest.
Typical study design:
community health survey
(approximate synonyms cross-sectional study,
descriptive study)
Typical study designs:
cohort, case-control,
experimental
Epidemiologic Study Designs
Measure of Disease Frequency
1.
2.
Cumulative Incidence (Incidence, Risk, I, R)=
Number of new case over a time period
Population at risk at the beginning
- Indicates the risk for the disease to occur in population at risk over a
time period. Value from 0 to 1.
Incidence Density (Incidence Rate, ID, IR)=
Number of new case over a time period
Person time at risk
Indicates the velocity (speed) of the disease to occur in population over a
time period. Value from 0 to infinity
3.
Prevalence (Point Prevalence):
Number of new and old cases at a point of time
Population
Indicates burden of disease. Value from 0 to 1.
Levels of Disease Occurence
Sporadic level: occasional cases occurring at
irregular intervals
Endemic level: persistent occurrence with
moderate to high level
Epidemic or outbreak: occurrence clearly in
excess of the expected level for a given time period
Pandemic: epidemic spread over several countries
or continents, affecting a large number of people
Attack rate:
# cases of disease that develop during
________defined period_______
# in pop. at risk at start of period
(usually used for infectious disease outbreaks)
Measures of Disease Frequency
Measures of Disease Frequency
Measures of Disease Frequency
Measures of Disease Association
The chances of something happening can be
expressed as a risk or as an odds:
PROPORTION
RISK = the chances of something happening
the chances of all things happening
RATIO
ODDS= the chances of something happening
the chances of it not happening
MEASURES OF DISEASE ASSOCIATION (2)
The relative risk is a ratio of two risks.
Assume that among the 100 people at risk, 50 are men
and 50 women. If 15 men and 5 women develop
influenza, then the relative risk of developing influenza
in men, as compared with women, is:
Risk in men = 15/50
divided by
Risk in women = 5/50
15/50 ÷ 5/50 = 3.0
(Note that from the way the question was put, the two
risks are cumulative incidence rates.)
Measures of Disease Association (3)
The odds ratio is a ratio of two odds
The odds in men = 15/35
divided by
The odds in women = 5/35
15/35 ÷ 5/45 = 3.9
We conclude that the odds of men getting influenza
over the year are 3.9 times as high as the odds of
women getting influenza.
Thought question: note that the odds ratio in this
example (3.9) is larger than the relative risk (3.0).
Is this always the case? Is this important?
Ruang Lingkup Epidemiologi
Use of Epidemiology
Issues in Epidemiology
- Bias
- Confounding
- Hill’s Causal Criteria
Use of Epidemiology
Causation
Natural History
Description of
Health Status
Evaluation of Intervention
Konsep Dasar Timbulnya
Penyakit
Trias Bloom (Konsep Keseimbangan)
Natural History of Disease
The Basic Triad Of Descriptive Epidemiology
TIME
PLACE
PERSON
Description of Disease Distribution
in the Population
Disease affects
mostly people under
five years of age
Disease affects
people living
alongside the river
Disease reaches its
peak in frequency in
Week 6
The Basic Triad Of Analytic Epidemiology
HOST
AGENT
ENVIRONMENT
Factors Influencing Disease
Transmission
Agent
Environment
• Infectivity
• Weather
• Pathogenicity
• Housing
• Virulence
• Geography
• Immunogenicity
• Occupational setting
• Antigenic stability
• Air quality
• Survival
• Food
Host
• Age
• Sex
• Genotype
• Behaviour
• Nutritional status
• Health status
Natural History of Disease
Timeline of Infectiousness
Dynamics of
infectiousness
Latent
period
Infectious
period
Non-infectious
Susceptible
Time
Dynamics of
disease
Incubation
period
Symptomatic
period
Non-diseased
Susceptible
Time
Screening
Definition
Screening and Surveillance Difference
Definition
Examination of whole populations aims to
detect those at risk of a specific disorder or
condition who are likely to benefit from further
investigations and possibly treatment or action
to prevent the disorder or condition or its
consequences.
Surveillance involves investigating the
distribution and possible causes of diseases
and conditions within the population.
Active
Surveillance (based on active case finding)
Passive Surveillance (based on reporting)
REFRESH YOUR KNOWLEDGE
Pada 120 siswa SMP pada 1 januari dilakukan
screening anemia. Pada 120 siswa, 30 siswa (1
januari 2005) didiagnosa anemia. Pada 31
desember di skrining ulang, didapatkan 10 orang
lagi yg membutuhkan pengobatan. Angka
insidensi :
a. 10/90
b. 30/90
c. 10/120
d. 30/120
e. 40/120
Pada suatu wilayah kerja, diketahui jumlah karyawan
laki-laki yang menderita HIV pada tanggal 1 Januari
2012 sebanyak 50 dari 1000 orang. Pada tanggal 1
Januari 2013 terdapat 62 kasus dari 1000 orang
termasuk 50 orang tang terdeteksi sebelumnya.
Berapa prevalensi HIV pada tanggal 1 Januari
2013?
a. 5%
b. 6,2%
c. 1,2%
d. 50%
e. 62%
Sebuah penelitian ingin mencari risiko hipertensi pada PNS.
Didapatkan data sebagai berikut:
Dari data diatas, nilai yang
digunakan untuk menentukan
kekuatan hubungan antar
variable adalah?
a) Nilai p
b) Proporsi
c) Frekuensi
d) Ratio Odds
e) Interval kepercayaan
Dari data diatas, risiko mengalami hipertensi tertinggi
terdapat pada golongan ?
Thank You
Questions?