Demography
Snyos – people
Ypagly – draw or write
A study of people population size, draw or write its composition and spatial distribution as affected by
births, death and migration.
SOURCES OF DEMOGRAPHIC DATA:
1. Surveys
1. Census- De jure or De Facto
2. Sample Survey
2. Continuing Population Registers
3. Other Records and Registration Systems
Sources of Demographic Data
-censuses, sample surveys and registration systems
Census – is an official and periodic enumeration of population.
2 ways of assigning people when the census is being taken:
• De Jure
• De Facto
• De Jure
• - people are assigned to places where they usually live regardless of where they are at the
time of census
• De Facto
• -people are assigned to the place where they are physically present at the time of the census,
regardless of their usual place of residence
• Situation: Rico is a Cebuano and he grew up in Davao. He decided to study BS Nursing in
Zamboanga. At the time of census, Rico was in his dormitory in La Purisima St. Zamboanga
City.
• Using de jure and de facto census, where will Rico be assigned?
Components
• Population Size
1. Natural Increase
2. Net migration
3. Annual growth rate
• Population Composition
1. Age Distribution
2. Median Age
3. Dependency Ratio
4. Sex Ratio
5. Population Pyramid
6. Others: Occupational group, economic groups, educational attainment, and ethnic groups
Population Distribution
Urban-Rural
Crowding Index
Population Density
• Crowding Index
Total # of persons in the household
• Crowding Index = Number of rooms in the house
• Population density = total size of the population x 1000
total number of square meters
• Fertility Rate p75 (Cuevas)
-Crude Birth Rate
-General Fertility Rate
Vital Statistics
• a tool in estimating the extent or magnitude of health needs and problems in the community.
• Through vital statistical indicators, the nurse is able to describe the health status of the people
which serves as the basis for developing, implementing and evaluation programs and
intervention strategies.
Mortality Rates
• Crude Death Rate
• Specific Mortality Rate
• Infant Mortality Rate
• Neonatal Mortality Rate
• Post-neonatal Mortality rate
• Maternal Mortality Rate
• Proportionate Mortality Rate
• Swaroop’s Index
• Case Fatality Rate
• Cause-of-Death Rate
Morbidity Rates
• Prevalence
• Incidence Rate
How to compute for the following:
1. CRUDE BIRTH RATE – NATALITY RATE
Total no. of live birth x 1000
Total population
2. How fertile the community is? Reproductive
Age = 13-49 y.o ave.menopausal 50 y.o
Total no. of live births x 1000
No. of female of reproductive age
MORBIDITY RATES
1. PREVALENCE RATE (PRE-OLD AND NEW)
(Inc- new /acute)
*Prevalence – incidence, unless the disease is acute where the total no of cases may be equal to the no
of new cases.
Include everyone who are sick regardless of time of diagnosis.
Total no. of cases of a Disease x 100
Total population or population examined
New cases – cases diagnosed within the given time.
ex. PTB 2010
Old case – diagnosed before 2016 but still positive in 2016
New case- diagnosed in Jan to Dec 2016
2. INCIDENCE RATE:
*old cases not included
No. of New cases of a disease
Total population x 100,000
Population at risk of developing the disease
3. ATTACK RATE- a more accurate measure of the risk exposure.
- use during epidemic
- use in epidemiologic investigation
No. of persons acquiring a diseases during a specific period x 100
No. of expected to same disease in the period
MORTALITY RATE
1. CRUDE DEATH RATE
- Not to compare population
- Useful when considered as a series in a trend
TOTAL No. of deaths x 1000
Total population
*If total death rate is decrease= good health
3. CRUDE- SPECIFIC DEATH RATE
No.of Deaths from Specific cause x 100,000
Total population
* Basis for leading cause of death
3. AGE- SPECIFIC DEATH RATE
No. of death in an age group x 100,000
population aged 1-4 y.o
* Nutritional and immunization status of the
population.
-multiplication factor:
ex. 1-2 per 100,000 aged 1-4 y.o died
*Attack, Swaroop’s, Prevalence x 100
4. PROPORTIONATE
Proportionate Mortality rate x 100
Total no. of deaths
Ex. Teacher proportionate mortality rate
Cancer proportionate mortality rate
Infant proportionate mortality rate
5. SWAROOP’S RATES
No. of Deaths age > 50 y.o x 100
Total no. of Deaths
*The most sensitive indicator of health status of a population (most accurate)
-100% Swaroop’s index ( all who died are 50 y.o. and above.
6. CASE FATALITY RATE
To know if the disease is Fatal
- reflects the killing power of a disease
No. of Deaths from a specific disease x 100
No. of Cases of the disease
ex. SARS case is 12 death is 2
2 x 100 = 16.6
12
7. MATERNAL MORTALITY RATE
To know from those who are pregnant, how
many died due to pregnancy-
No. of Deaths due to pregnancy, labor or puerperium (Maternal Deaths ) x 1000
Total no. of livebirths (no. of women who got pregnant)
*NOTE- no. of IUFD (still birth) may be added to the denominator
8. INFANT MORTALITY RATE (Death in the First year)
- No. 2 best indicator of health status of a popu-
lation
- The lesser the healthier
No. of Deaths aged 0-11 mos (or 0-1 yr) x 1000
Total No. of Live births (no. of infants)
Note: DO NOT add stillbirth
NEONATAL MORTALITY RATE
- age is 0- 28 days (Death in first month)
No. of Deaths aged 0-28 days x 1000
Total no. of Live births
9. EARLY NEONATAL (hobdomadol) mortality rate (death in the first week) 0-7 days old
No. deaths aged 0-7 days x 1000
Total no. of Live births
10. PERINATAL MORTALITY RATE
No. of Deaths aged 0-28 days + no. of IUFD’s (stillbirths) x 1000
Total No. of Live births + No. of IUFD’s
Ex. Neonatal death = 5 IUFD=3 live birth= 145
=5+3 x 1000 = 8 x 1000 = 8,000= 54.05
145+3 148 148
Individual activity
• Situation :
• Arlene, a public health nurse assigned in barangay Mabolo is to submit a report on the data
gathered from this barangay during the mid-year of July 2016. Data included are the
following:
Situation. Computational skill
QUESTIONS: Assignment
• What is the total population of the barangay?
• What’s the crude birth rate of the barangay?
• Compute for the specific death rate for tuberculosis.
• What’s the maternity mortality rate?
• What’s the early neonatal mortality rate?
• What’s the neonatal mortality rate?
• Compute for the infant mortality rate.
• Compute for the perinatal mortality rate.
• Compute for attack rate of tuberculosis.
• What’s the crude death rate of this barangay?
• What’s the Swaroop’s index of this community?
Epidemiology
• Greek word
• Logos – study
• Demos – people
• Epi – study what is upon the people
• The focus of study is disease occurrence among population groups
• Studying the Etiology and distribution of
• disease and conditions in humans should positively confirm the health of the populations.
• The data obtained and analyzed in EPIDEMIOLOGY is used to rank the level of
• Health a given population in relation to another segment at an identified time.
*Epidemiology is the backbone of the prevention of the disease
Epidemiology triangle
Basic Concepts:
Epidemiology Triad
Transmission
Incubation period
Herd immunity
Factors affecting distribution:
• PERSON
Intrinsic characteristics
• PLACE
Extrinsic factors
• TIME
Temporal patterns
• Infectious
- not easily transmitted by ordinary contact, requires a direct inoculation through break in skin or
mucous membrane
Contagious
- easily spread and is directly transmitted from person to person
PATTERNS OF DISEASE
SPORADIC – intermittent occurrence of a disease
ENDEMIC – continuous or constant occurrence in a certain area
EPIDEMIC – sudden increase in a number of cases in a short time
PANDEMIC – Worldwide epidemic
Patterns of Disease Occurrence:
• Epidemic
• sudden increase in a number of cases in a short time
• Epidemic potential
• Endemic
-Continuous or constant occurrence in a certain area
• Sporadic
• intermittent occurrence of a disease
• Pandemic
