demography

 Define demography and recognize its importance
and methods of study.
 Describe population estimations in the census and
inter-census years.
 Describe & interpret different profiles of the
population pyramid
 Categorize data sources for vital statistics
 Differentiate between proportion, ratio, and rate.
 Calculate Vital indices [fertility - birth, morbidity
(disease) –death (mortality)].
 Recognize the relationship between MDGS & vital
indices

3
Demography
 It is the study of population
characteristics, size or number,
structure, geographical distribution as
well as the changes of these
determinants over time.

It is very important to public health as
it provides:
 The number of population to be
covered by health services,
 The amount of vaccines or drugs
needed every year,
 The characteristics of population in
different geographical areas that can affect
health,
 Data necessary to calculate health
indicators (used in comparison, planning,
evaluation and prediction of community
health services and programs)
Value of
demography

I- Size (census &
Intercensus)
II-Population growth
pattern (RNI)
III- Composition
(Population pyramid)
V-Health indicators
IV-Population
distribution (maps)

I-Population census
Def. To enumerate people in certain area (country)
at certain time
It collects data about:
 the number of population,
 characteristics as age, sex, and socio-economic data as
income, crowdness index, occupation, education level
etc..
 Census is done every 10 years since it is time, effort and
cost consuming.
 Mid-year population is the number of population
calculated from census at the 1st of July (it was chosen
as a standard for any census).

I-Population census
What is Importance of census:
 Calculate the actual number of population living in
that country at the year of census.
 For planning for future health care programs.
 Provides general characteristics of the population used
in comparison over periods of time, or comparison with
other foreign populations.
 To estimate population in years between censuses.
 Calculate vital statistical rates.

I-Population census
Drawbacks of census:
 Expensive, needs time, money, personnel. As it needs long time in
data collection and analysis the results will be irrelevant i.e census
is done in 2006 and results announces in 2010.
 Data may be inaccurate: People tend to round their age because
they do not know their birthday exactly. People hide their real
income and others hide the actual number of children they have.
 There are some areas where people are moving . They are missed
or under-estimated.
 Lack of co-operation between people and census data collectors.
 Data collectors may fill questionnaire by themselves when houses
are empty.

Inter-census Population
Certain methods are used to calculate
the number of population at years
in between census.

Estimation of
population in
Between census

if we need to estimate population number at 1994
 we deduce population census at 1990 from that at
2000 (difference between 2 subsequent censuses)
 then divide that difference by 10 (to find the
annual increase of population) multiply this
annual increase by 4 to get the increase in 4
years.
 Add the result to population number in census
1990 to get population number in 1994. This
method presume that population increase yearly
with the same amount which is not true.
Inter-census population

Census
1990 = 60 millions
2000 = 80 millions
1994 ?
Census 2000 - census 1990
80 - 60 = 20 millions
Annual increase of pop.= 20 / 10 = 2 millions
Pop. Increase in 4 years = 2 x 4 = 8 millions
Pop. Number in 1994 =
8 + 60 (pop. 1990) = 68 millions

 is the difference between crude birth rate
and crude death rate which is considered as
the number of population added per year.
 Multiply this increase by the number of
years (e.g.4 for 1994) then added to the
census of 1990 (as the previous example).
 This method neglects the migration factor
that can increase/decrease population
number whether to or from the country.

RNI = crude Birth rate - crude death rate =
number of pop. Added / year (Annual increase of pop.)
Pop. Increase in 4 years = x 4 = ---- millions
Pop. Number in 1994 =
Pop. No. in 4 years + 60 (pop. 1990) = 68 millions
------------------------
Crude Birth rate = No. of live births / mid year pop. X 1000
1994?

 It equals (crude birth rate + immigrants to
the country) minus (crude death rate +
emigrants outside).
 Then estimated population is calculated in
arithmetic way as previous.

 By plotting a straight line connecting
population numbers in all previous censuses
(x-axis represents years of censuses) and (y-
axis represents population number in million).
 We can know from that graph the estimated
population number in years between 2
censuses
 also we can predict the number of population
in the future by extending the line.

120
100
80
60
40
20
0
1990 2000
Graphic method
No
Of
Pop.
2010
1994
y
1996

 It is calculated by certain equation that
depends on the last two population
censuses, the number of years in between
censuses and the annual rate of increase.
 This method assumes that population
growth is not linear (or steady every year).

1- The census of Egypt in 1996 was 60 millions,
while in the year 2006 was 75 millions.
Calculate the expected population number in
the year 1998 and 2004 by two different
methods.

1-Arithmatic method:
Census2006 – census 1996 =75-60=15
million
Annual increase= 15milion/10years=
1.5million
Census at the year 1998=60+2X1.5=63
million
Census at the 2004=75-2X1.5=72
million
2-Graphic method:

120
100
80
60
40
20
0
1996 2006
Graphic method
No
Of
Pop.
1998
y
2004
72 m
63 m

pattern
Changing population growth pattern (transition)
is mainly affected by:
births, deaths, migration (in some countries it is
an important factor) and life expectancy.
The process of a change in society’s populations
from a condition of high birth rate and death
rate and low RNI to a condition of low birth
rate and death rate and low RNI and even to
negative growth (can be described by 5 stages).

More healthcare/education/empowered women
Amazon
population
Ethiopia India UK Germany
Birth rate High and
fluctuating
High and
steady
Rapidly
decreasing
Low and
fluctuating
Slowly
falling
Death rate High and
fluctuating
Rapidly
falling
Slowly
falling
Low and
fluctuating
Low and
fluctuating
Population
growth rate
Zero Very high High Zero Negative
Population
size
Low and
steady
Rapidly
increasing
Increasing High and
steady
Slowly
falling

Life expectancy:
is the average number of years that can be expected to
be lived by any individual at certain age.
 Life expectancy is directly proportional to country
development, socio-economic level, health services
standard, use of new technology, good nutrition, healthy
environment, literacy etc.
 In developed countries the life expectancy of new
borne is 85 years while in under developed countries it
reaches 40 years.
 In Egypt, life expectancy at birth (72.7 years) 2016
(Males 71.4 years) (Females 74.2 years)
pattern

III-Population pyramid
 It is a graphical presentation of population by age
and sex (Histogram).
 Vertical axis represents age groups(in five years)
and
 the horizontal axis represents percentage of
population of these age groups in relation to sex.
Characteristics of the population pyramid :

 Base of the pyramid represents the birth rate.
 Height represents the number of years to be lived at
specific age.(life expectancy)
 Top represents the percentage of old age groups.
 Slope of the pyramid represents the age specific death
rates.
 Dependency ratio: is the number of young ages below
15 years old plus the number of old ages over 65(who
are dependents) per 100 persons from 15 to 64(who
are independent).
 Percentage of males and females at each age group.

 Total Dependency ratio: is the number of young ages
below 15 years old plus the number of old ages over
65(who are dependents) per 100 persons from 15 to
64(who are independent). In Egypt = 62.3% (2016)
 Youth dependency ratio: is the number of young ages
below 15 years old per 100 persons from 15 to 64(who
are independent). In Egypt = 53.8% (2016)
 Elderly dependency ratio: is the number of elderly
people > 65 years old per 100 persons from 15 to
64(who are independent). In Egypt = 8.5% (2016)

Definition
Percentage Percentage

1- Birth rate
2-
Life
expectancy
3- Old age group
5- Dependency ratio=
No of dependents/
No. independents
6- Percentage of males
and females at
each age group
Characheristics

Wide base
Short
height
Expansive model
Rapid growth

Pop.Pyramid 1950 Pop. Pyramid 2000 Pop. Pyramid 2050
Base is wide
Egypt

It follows the expansive type of model, where:
 1. The base is wide due to high birth rate,
 2. Tapers rapidly due to high specific death rates
especially 0 to 5 years,
 3. The top is narrow due to low proportion of
elderly.
 4. The height is short due to short life expectancy.
Population pyramid

it shows an expansive type (stage 2), where:
 1. The base is less than that of the 1950 due to
decrease in birth rate.
 2. Fertility decline is evident by that the
proportion in the age period 0-4 and 5-9 are less
than that in the period 10-14
 3. More decrease in the different age specific death
rates,
 4. Life expectancy has increased
 5. Old age group increased.

Population pyramid

It is expected to be of a Stationary type, where:
 1. The different age group proportion will be
almost equal due to almost equal birth and
death rates
 2. There a slow tapering at old age due to
expected low age specific death rates. More
flat top due to expected increase in elderly
sector.
 3. Longer life expectancy may reach 80 years.


IV-Population
distribution (maps)

Show Desktop.scf
Population Distribution
in Egypt
.
95% of pop.
Nile (5%)
Pop. density is
Very high

V-Health indicators
What are the values of health indicators?
1- Describing and diagnosis of community health
problems.
2- Comparing different countries at the same time
or changes in a country at different times.
3- Planning of health services and programs.
4- Evaluation of community health services and
programs.
5- Prediction of future health needs of the
community.

What are the health indicators used???
 (Vital rates): birth, fertility, death, and
morbidity.
 Annual economic growth rate
 Per capita income
 Literacy percentage
 Dependency ratio
 Life expectancy
IV-Health indicators

Health indices (vital rates)
What are the vital indices???
 Vital indices are quantitative measures that
describe and summarize vital events in the
human life e.g.:
Human life
Marriage
Fertility
Diseases
Migration
Birth Death

Ratio:
 The relation between
two unrelated events
e.g. male to female ratio is
1:2.
Black to white ratio is 2:3.
Definitions

Proportion:
 Numerator part of
the denominator
Percent: When the base
is 100.
Definitions

Rate:
the frequency of an event
in a population in relation to
time
e.g. birth rate means the number of births
occurred in population during a year (or month).
N.B. The rate is usually multiplied by a
constant as 100 or 1000 to get an integer number.

4-Mortality
3-Morbidity
2-Fertility
1-Birth
CBR
CBR
GFR
ASFR
TFR
FR
GRR
NRR
Incidence
Prevalence
Attack
Case
fatality
CDR
ASMR
ASSMR
Cause
sp.MR
Proportional
MR

A-Crude birth rate (CBR)
 CBR= number of live births/ mid year
population X 1000 in a given year and locality.
Advantages: CBR describes the increase in
population over time, simple & easy to know
birth number (birth registries) and population
number at any time (from census),
Disadvantages: it is not specific for comparison
between countries because the denominator is
the whole population. The rate must exclude
men , young girls, unmarried, infertile, and
menopausal women.

A-Crude birth rate (CBR)
in Egypt
 CBR (1990) = 33.5 births / 1000 population
CBR (2010) = 23 births / 1000 population
CBR (2014) = 27.8 births / 1000 population
CBR (2016) = 30.3 births / 1000 population

B-Fertility indices:
 Fertility is the reproduction performance
of a population.
 Fertility indices include:
1. CBR
2. General Fertility Rate (GFR)
3. Age-Specific Fertility Rate (ASFR)
4. Total Fertility Rate (TFR)
5. Fecundity Rate (FR)
6. Gross Reproduction Rate (GRR)
7. Net Reproduction Rate (NRR)

2-General Fertility Rate (GFR):
 GFR=number of live births/number of
women (from15 to 49years) X1000. In the
same locality and year
 Since, women in the reproductive age
constitutes about 25 % (1/4) of the
population,
 therefore the GFR is considered to be about 4
times the crude birth rate.

2-General Fertility Rate (GFR):
Advantages: GFR is a more accurate index than the
crude birth rate because:
1. It is related only to females in the reproductive age,
2. It is more suitable for comparison between countries
since it eliminates difference in sex composition
Disadvantages:
1- it doesn’t consider that not all females in the
reproductive age are married and fertile
2-it did not consider the difference in females’ age
distribution in different countries.

3-Age-Specific Fertility Rate (ASFR):
 It is calculated for every five years of the reproductive
age of woman. It is important for differentiating
between fertility behaviors at different age groups.
 ASFR (15 - < 20) =Number of live birth borne to
mothers from 15 to 20 years old / number of women of
the same age(15-20 years) X1000. In certain locality
and year
 Therefore there are seven ASFRs (every five years) for
all women in reproductive period.

3-Age-Specific Fertility Rate (ASFR):
 Advantages: It is a better index than the
general fertility rate as it takes into account
the difference in age distribution of female in
different areas and the degree of fertility in
each age group.

4-Total Fertility Rate (TFR):
 It is the number of children that would be
born to a woman if she passes through her
child bearing period following the age
specific fertility rates in a given year and
locality.
 TFR in Egypt (2016) = 3.5 children /
woman

The Total fertility rate (TFR ) is
calculated as:
TFR = ∑ ASFR (for single year
age groups)
TFR = 5 ∑ ASFR (for 5-year age
groups)

TFR Calculation (Practical example)
Estimate of the average annual TFR for all
women aged 15-49, Egypt, 1997-2000.
TFR= 5 (.051 + .196 + .208 + .147 +
.075 + .024 +.004) = 3.53
Where: the figures in parentheses are
age-specific rates for the 15-19, 20-
24, ... , 45-49 age categories,
respectively.

5-Fecundity Rate (FR):
It is the number of live births born per
thousand married women in a certain locality
and year.
Advantages: It is better index than the general
fertility rate as it includes only married
women.

6-Gross Reproduction Rate (GRR):
 The GRR includes only born females, (expected to be
future mothers) per 1000 women in the childbearing
period.
 GRR = Total Fertility Rate X Proportion of females in
relation to total birth.
 In Egypt, it is estimated to be 1.5, which means that
every woman will give birth to 1 to 2 women during
her childbearing period.
 Disadvantages: it did not consider the possibility of
death of women during their child bearing period.

7-Net Reproduction Rate (NRR):
 It takes into consideration the deaths of women
during their child bearing period using life tables of
females.
 NRR = Gross Reproduction Rate X Life expectancy
of females during childbearing period from life
tables.
 Advantages: It is the best measure of fertility.

1-Age and sex structure of the population:
The larger the number of women in the childbearing
period in a certain population the higher is the fertility
level in such population.
2-Age of marriage: The younger the age of marriage the
higher is the fertility.
3-Socioeconomic conditions: Higher economic status,
higher status of women and higher level of education are
associated with low fertility rates.

4 -Fecundity: The physiological capability of
couples to reproduce it is affected by their health
conditions.
5- Fertility Motives:
Fertility motives are the reasons that motivate a
couple to increase or decrease the number of
children they will have. Several motivations
explain such attitude:

1- Economic motives: If the children are becoming a source of
income to the family, this will lead to the desire of family to have a
large number of children.
2-Health motives: The high infant and preschool death rates lead to
worry of the family of loosing their children; therefore they
compensate for these expected losses by having more children;
3-Cultural and religious motives:
- Traditions and community believes to have large family since this is
considered as a source of power and social status.
- Some wives believe that large number of children ensure security
and prevent divorce.
- Some believes that religion is against family planning.

1- Economic motives:
Children would need large
expenses to enjoy good education
and health. Thus, with a fixed
income smaller family will enjoy
better living standards.
2- Health motives:
- The health of the mother and children are better
with spacing of pregnancies.
- Large family can have a bad effect on the
physical, mental, social and spiritual health of the
family.

Dimensions of the population problem in
Egypt are summarized in:
A-Population Growth,
B-Population Characteristics, and
C-Population Distribution

Show Desktop.scf
Population Growth
.

 Improvement in the health conditions in the last few
years has lead to a decrease in the death rate and a
proportion of the birth rate and thus the rate of
natural increase has remained high.
 But, due to past experience of high birth rate a large
number of the population is entering the fertile age
group and therefore the population growth will
remain high for years before starting to decline.

 Total Dependency ratio 62.3%,
 CBR = 30.3/1000, CDR = 4.7/1000. RNI =2.51.
 Life expectancy for males=71.4, and for females
74.2years,
 infant mortality rate=19.7/1000 live birth,
 maternal mortality rate=33/100,000 live births
 TFR =3.5 children / woman
 Literacy percent = 73.8%

 About 95% of population live around the Nile in
a very narrow area representing 5% of Egypt
land, so population density is very high.
 Population problem is the result of inadequate
equilibrium between income (resources)
increase and population increase.

 The solution of this problem:
I-long term solution
(increasing resources) by
investment in industry,
increasing land
cultivation and
productivity, exportation,
building new factories,
reclaiming desert, female
education etc.
II-Short term
solution is by
decreasing birth rate.
In other words we
empower low fertility
motives and try to
decrease high motives.

C-Morbidity indices:
 They are disease occurrence data that
are used in disease surveillance.
 The most widely used measures of illness
in a population are
incidence
prevalence rates
Attack rate
Case
fatality
rate

 Number of new cases of illness in a specified time /
Population at risk X1000 (or 10000) in the same time and
place.
 The population at risk can be the entire population in a
specified area, or specific group of people such as people
of certain age, sex etc.
 ITS VALUE:
 • It is very important parameter in epidemiology.
 • It tells us about new cases and thus we can associate this
event of illness with the possible causal factors.
 • It can be calculated for both chronic and acute diseases.
 • It measures the relative importance of one illness over
the other

Two types of prevalence measurement:
A-Point prevalence: Number
of current cases (old & new) of
an illness at a point of time /
Population examined at same
point of time x constant. Point
of time is a short period (days,
month).
B-Period
Prevalence: Number
of current cases of an
illness over a period of
time / Population
examined at the same
period X constant.
Period of time is longer
(months, years).

The prevalence is an indicator of the burden of
disease on the population since it reflects the
number of cases whether old or new.
It measures the relative importance of one
illness over the other
Can be used for evaluation of health services.

 It is an incidence rate estimated in an
epidemic (or outbreaks) when observation
of population at risk is for short period.
 Overall Attack rate: Number of new cases
of specific disease reported during epidemic
period of time / Total number of persons at
risk during the same time X 100

Number of deaths of cases from specific illness in specific time
Number of cases of the same illness in the same time and place X K
Value: It measures the virulence of the agent and
the severity of the disease. Therefore is
considered as a morbidity measure although it
involves deaths.

D-Mortality indices or Death indices
 They are not effective as the morbidity indices
but sometimes they are the only available data.
Values or benefits of death indices:
 Death rates are important indicator of the health
status in a community.
 They can indicate the impact of a particular
cause on the population.
 They can study the relation of a certain cause to
the disease occurrence.

 Crude Death rate (CDR)
 Cause specific death rate
 Age specific death rate
 Sex specific death rate
 Age-sex specific death rate
 Infant mortality rate (neonatal – post neonatal)
 Perinatal mortality rate
 Maternal mortality rate (ratio)
 Proportional (relative) mortality rate
 Case – fatality rate.

 Is the number of deaths in a specific period/ mid
year population at the same period and place X
1000.
 The crude death rate in Egypt has decreased to
reach 4.7 / 1000 population in 2016. This
improvement can be attributed to community
development, better health services, application of
modern techniques, new drugs, health education
etc.
 Disadvantages: The CDR is not specific rate as it
includes all deaths in a population irrespective of
its age, sex distribution or cause of death.
1-Crude
death rate
(CDR):

Number of deaths from a specific cause
in a specific time/ Mid year population at
the same time period X constant
The cause specific mortality rate
describes the severity of the disease to
cause deaths.
Cancer has high cause specific MR.
2- Cause
Specific
Mortality
Rate:

 Number of deaths in a specified age group and
specific time /Population of the same age group
and at the same time period X constant
 The age specific mortality rates describe the
rate of deaths in each age group.
 The causes of deaths among age groups are
different and therefore by using this rate we
can prioritize these causes to be solved.
3-Age specific
Mortality
Rate ASMR:

 Number of deaths in a certain sex in a specific
time /Population of the same sex at the same
time period X constant
 The sex specific mortality rate describes the
rate of deaths in each sex.
 The causes of deaths among different sex are
different and therefore by using this rate we
can identify health problems related to sex.
4-Sex specific
Mortality
Rate ASMR:

 Number of deaths of males or females at
certain age group at certain area and time
/ number of males or females of the same
age group X 1000 in the same area and
time.
5- Age- Sex
specific
Mortality
Rate
ASSMR:

Maternal Mortality Ratio:
 Number of deaths among women due to causes
related to pregnancy, labor and puerperium in a
specific year & locality /live births in the same year
& locality X 100,000
 It accounts for the greatest number of deaths
among women in reproductive age in devloping
countries. (33 deaths /100000 live births 2016)
7- Maternal
Mortality Ratio

Proportional (relative) mortality Rate:
 Number of deaths from a specific cause in a
specific time /Total deaths from all causes X
constant
 It describes the relative importance of a specific
disease as a cause of mortality in relation to
other causes.
8- Proportional
(relative)
mortality Rate:

 The risk of dying and contracting most
diseases are related to age and sex.
 So, Crude death rate and overall incidence and
prevalence rates depend critically on age-sex
composition of any population.
 For example, a relatively older population
would have a higher crude death rate than a
younger population.

 In order to compare overall morbidity rates and
crude death rate across countries,
 to neutralize the difference in age and sex
composition by using:
and
1-
Direct
method
2-
Indirect
method

 The choice of method is usually governed by
the availability of data and their accuracy.
 However, indirect standardization is more
commonly employed for mortalities and
incidences.
 Direct standardization is more commonly
employed for prevalence.

 In this method we use (a standard population).
This is usually one of the following : either one of
the study populations or the total of both
populations.
 Then, the age-sex specific rates from each of the
populations under study are applied to the
standard population to give age-sex adjusted
rates.
Death rates

 The age –sex specific rates from a standard
population are applied to each of the
populations of interest to give standardized
(morbidity or mortality) ratios which in turn are
used to calculate age-sex adjusted rates.
Death rates

Is Data collection important???
Yes or No. HOW??????
 1. Diagnosis of community health problems &
assess community needs
 2. Helps in the comparison of health status and
diseases in different countries and in one
country over the years.
 3. Evaluation of health services & health
programs.
Sources of data collection

Primary Sources:
(the investigator
"s" collects data
not present before)
It can be either
qualitative or
quantitative.
Secondary
Sources: (already
present data,
routinely collected
and reported by
government or
authorized centers)

1-Qualitative data:
will provide us with
insight on personal
ideas, opinions, and
attitudes.
It can be carried out
by focus group and in-
depth interview.
2-Quantitative data:
Survey study. These are field
investigations that are carried out to
find the frequency of a specific
disease in a population.
Either we include every member
of the population (census) or take
sample survey, in which only a
selected part of the population is
included.
The survey can provide more
detailed information and also it has
the ability to evaluate the data
collection methods.

1-National
census 2-
Surveillance
3-Records
4-International
Classification of
diseases (lCD)

1-National
census
It provides a wealth of
demographic and economic
data.

2-
Surveillance
It refers to special reporting system
(notification) which is set up for a particular
important health problem or threatening
disease.

3-Records
e.g. birth, death certificates and health care
registries as hospital records, school records,
data of insured groups, armed forces,
absenteeism of workers.

Secondary Sources of data collection
3-Records
Importance of records:
1 - Birth certificates provide
denominators for computation of
rates that describe events related to
infancy and pregnancy, labor,
puerperium.
2- Disease notification and
registration provide data for
calculation of
- Incidence rate, prevalence rate.
- Relative fluctuation of disease and
its geographic distribution.
- Data for planning and evaluation of
preventive measures.
Drawbacks of records:
-Variation in diagnostic criteria
and definition of case.
-Incomplete & inaccurate data
records (as in hospital files).
-The number of notified cases is
far less than the number
occurring.
- Records of special subgroups
who have special characteristics
will limit the generalization of
data on the whole community.

4-International
Classification of
diseases (lCD)
It provides a more standard way to
record diseases and health problems.
It is used to classify diseases and
other health problems in a standard
way.
It allows the storage and retrieval of
diagnostic information for clinical and
epidemiological purposes.
Provides the basis for the collection
of national mortality and morbidity
statistics by WHO.

Summary
Primary Sources:
1-Qualitative:
focus group &
indepth interview
2-Quantitative:
survey
Secondary
Sources:
1. Census
2. Surveillance
3. Records
4. ICD

 In September 2000, building upon a decade of
major United Nations conferences and
summits, world leaders came together at the
United Nations Headquarters in New York to
adopt the United Nations Millennium
Development Declaration.
 The Declaration committed nations to a new
global partnership to reduce extreme poverty,
and set out a series of eight time-bound
targets - with a deadline of 2015 - that have
become known as the Millennium Development
Goals (MDGs).

 Eradicate extreme poverty and hunger.
 Achieve universal primary education.
 Promote gender equality and empower woman.
 Reduce child mortality.
 Improve maternal health.
 Combat AIDS / Malaria and other diseases.
 Ensure environmental sustainability.
 Develop a global partnership for development.

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