Demography lecture for students of community medicine which is an important topics both for undergraduate and post graduate students.
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Demography lecture ppt
2. Demography, as understood today, is the scientific study
of human population. It focuses its attention on three readily
observable human phenomena : (a) changes in population
size (growth or decline)
(b) the composition of the
population and
(c) the distribution of population in space.
It deals with five "demographic processes", namely
fertility,
mortality, marriage, migration and social mobility.
These five processes are continuously at work within a
population determining size, composition and distribution.
5. The history of world population since 1650 suggests that
there is a demographic cycle of 5 stages through which a nation
passes:
(1) FIRST STAGE (High stationary):
This stage is characterized by a high birth rate and a high
death rate which cancel each other and the population
remains stationary. India was in this stage till 1920.
(2) SECOND STAGE (Early expanding):
The death rate begins to decline, while the birth rate remains
unchanged. Many countries in South Asia, and Africa are in this
phase. Birth rates have increased in some of these countries
possibly as a result of improved health conditions, and
shortening periods of breast-feeding
6. (3) THIRD STAGE (Late expanding):
The death rate declines still further, and the birth rate tends
to fall. The population continues to grow because births
exceed deaths. India has entered this phase. In a number of
developing countries (e.g., China, Singapore) birth rates have
declined rapidly.
(4) FOURTH STAGE (Low stationary) :
This stage is characterized by a low birth and low death rate
with the result that the population becomes stationary.
Zero population growth has already been recorded in
Austria during 1980-85. Growth rates as little as 0.1 were
recorded in UK, Denmark, Sweden and Belgium during
1980-85. In short, most industrialized countries have
undergone a demographic transition shifting from a high
7. birth and high death rates to low birth and low
death rates.
(5) FIFTH STAGE: (Declining)
The population begins to decline because birth rate
is lower than the death rate. Some East European
countries, notably Germany and Hungary are
experiencing this stage.
8. Growth rates :
When the crude death rate is substracted from the
crude birth rate, the net residual is the current
annual growth rate,exclusive of migration.
11. Demographic indicators have been divided into two
parts –1.Population statistics and
2. vital statistics
Population statistics include indicators that measure the
population size, sex ratio, density and dependency ratio.
Vital statistics include indicators such as birth rate, death
rate, natural growth rate, life expectancy at birth,
mortality and fertility rates.
These indicators help in identifying areas that need
policy and programmed interventions, setting near and
far-term goals and deciding priorities, besides
understanding them in an integrated structure.
33. By fertility is meant the actual bearing of
children.
Some demographers prefer to use the word
natality in place of fertility.
A woman's reproductive period is roughly
from 15 to 45 years - a period of 30 years. A
woman married at 15 and living till 45 with her
husband is exposed to the risk of pregnancy for
30 years, and may give birth to 15 children, but
this maximum is rarely achieved.
34. Fertility depends upon several factors.
These are described below-
1. Age at marriage:
The age at which a female marries and enters the
reproductive period of life has a great impact on her fertility.
The Registrar General of India collected data on fertility on a
national scale and found that females who marry before the
age of 18 gave birth to a larger number of children than
those who married after . In India some demographers
have estimated that if marriages were postponed from the
age of 16 to 20-21, the number of births would decrease by
20-30 per cent .
35. 2. Duration of married life:
Studies indicate that 10-25 per cent of all births
occur within 1-5 years of married life; 50-55 per
cent of all births within 5-15 years of married
life. Births after 25 years of married life are
very few . This suggests that family planning
efforts should be concentrated in the first few
years of married life in order to achieve
tangible results.
36. 3. Spacing of children :
Studies have shown that when all births are postponed
by one year, in each age group, there was a decline in
total fertility. It follows that spacing of children may
have a significant impact on the general reduction in
the fertility rates.
4. Education :
There is an inverse association between fertility and
educational status. Education provides knowledge;
increased exposure to information and media; builds
skill for gainful employment; increases female
participation in family decision making; and raises the
opportunity costs of
women's time.
37. 5. Economic status :
Operational Research studies support the hypothesis that
economic status bears an inverse relationship with fertility.
The total number of children born declines with an increase
in per capita expenditure of the household. The World
Population Conference at Bucharest in fact stressed that
economic development is the best contraceptive. It will take
care of population growth and bring about reductions in
fertility.
6. Caste and religion :
Muslims have a higher fertility than Hindus. The
National
38. Family Health Survey-3 reported a total fertility rate
of 3.09 among Muslims as compared to 2.65 among
Hindus. Among Hindus, the lower castes seem to
have a higher fertility rate than the higher castes.
7. Nutrition :
There appears to be some relationship between
nutritional status and fertility levels. Virtually, all
well-fed societies have low fertility, and poorly-fed
societies high fertility. The effect of nutrition on
fertility is largely indirect.
39. 8. Family planning :
Family planning is another important factor in
fertility reduction. In a number of developing
countries, family planning has been a key factor in
declining fertility.
Family planning programmes can be initiated
rapidly and require only limited resources, as
compared to other factors.
40. 9. Other factors :
Fertility is affected by a number of physical,
biological,social and cultural factors such as
place of women in society, value of children in
society, widow remarriage, breastfeeding,
customs and beliefs, industrialization and
urbanization, better health conditions, housing,
opportunities for women and local community
involvement. Attention to these factors requires
long-term government programmes and vast
sums of money.
42. Fertility may be measured by a number of indicators,
as given below. Stillbirths, foetal deaths and
abortions,however, are not included in the
measurement of fertility in a population.-
1. Birth Rate
2. General Fertility Rate (GFR)
3. General Marital Fertility Rate (GMFR)
4. Age-specific Fertility Rate (ASFR)
5. Age-specific Marital Fertility Rate (ASMFR)
43. 6. Total Fertility Rate (TFR)
7. Total Marital Fertility Rate (TMFR)
8. Gross Reproduction Rate (GRR)
9. Net Reproduction Rate (NRR)
10. Child-woman Ratio
11. Pregnancy Rate
12. Abortion Rate
13. Abortion Ratio
14. Marriage Rate
44. Birth rate is the simplest indicator of fertility and is
defined as "the number of live births per 1000
estimated
mid-year population, in a given year". It is given by the
formula:
The birth rate is an unsatisfactory measure of fertility
because the total population is not exposed to child
bearing.
Therefore it does not give a true idea of the fertility of a
Population.
46. It is the "number of live births per 1000 women in
there productive age-group (15-44 or 49 years) in a
given year".
General fertility rate is a better measure of fertility
than
the crude birth rate because the denominator is
restricted to the number of women in the child-bearing
age, rather than the whole population. The major
weakness of this rate is that not all women in the
denominator are exposed to the risk of childbirth.
48. It is the "number of live births per 1000 married
women in the reproductive age group (15-44 or
49) in a given year".
50. A more precise measure of fertility is age-
specific fertility rate, defined as the "number of
live births in a year to 1000 women in any
specified age-group".
The age-specific fertility rates throw light on
the fertility pattern.
They are also sensitive indicators of family
planning achievement.
52. It is the number of live births in a year to 1000
married women in any specified age group.
54. Total fertility rate represents the average
number of children a woman would have if she
were to pass through her reproductive years
bearing children at the same rates as the
women now in each age group .
. It is computed by summing the age-specific
fertility rates for all ages; if 5-year age groups are
used, the sum of the rates is multiplied by 5.
This measure gives the approximate
magnitude of
"completed family size".
56. Average number of children that would be
born to a married woman if she experiences the
current fertility pattern throughout her
reproductive span.
58. Average number of girls that would be born to
a woman if she experiences the current fertility
pattern throughout her reproductive span (15-
44 or 49 years), assuming no mortality.
60. Net Reproduction Rate (NRR) is defined as the
number of daughters a newborn girl will bear
during her lifetime assuming fixed age-specific
fertility and mortality rates .
NRR is a demographic indicator. NRR of 1 is
equivalent to attaining approximately the 2-
child norm. If the NRR is less than 1, then the
reproductive performance of the population is
said to be below replacement level.
62. It is the number of children 0-4 years of age per
1000 women of child-bearing age, usually
defined as 15-44 or 49 years of age. This ratio is
used where birth registration statistics either
do not exist or are inadequate. It is estimated
through data derived from censuses.
66. There are several definitions of family
planning. An Expert Committee (1971) of the
WHO defined family planning as "a way of
thinking and living that is adopted voluntarily,
upon the basis of knowledge, attitudes and
responsible decisions by individuals and
couples, in order to promote the health and
welfare of the family group and thus contribute
effectively to the social development of a country“.
68. "Family planning refers to practices that help
individuals or couples to attain certain
objectives : ·
(a) to avoid unwanted births
(b) to bring about wanted births
{c) to regulate the intervals between pregnancies
{d) to control the time at which births occur in
relation to
the ages of the parent; and
{e) to determine the number of children in the
family.
69. An "eligible couple" refers to a currently
married couple wherein the wife is in the
reproductive age, which is generally assumed
to lie between the ages of 15 and 45.
70. the term target couple was applied to couples
who have had 2-3 living children, and family
planning was largely directed to such couples.
71. Couple protection rate (CPR) is an indicator of the
prevalence of contraceptive practice in the community.
It is
defined as the per cent of eligible couples effectively
protected against childbirth by one or the other approved
methods of family planning, viz. sterilization, IUD,
condom
or oral pills.
Sterilization accounts for over 60 per cent of effectively
protected couples .
.Demographers are of the view that the demographic goal
of NRR= 1 can be achieved only if the CPR exceeds 60 per
cent.
99. There are two basic types of IUD : non-medicated and
medicated. Both are usually made of polyethylene or
other polymers; in addition, the medicated or bioactive
IUDs release either metal ions (copper) or hormones
(progestogens).
The non-medicated or inert IUDs are often referred to as first
generation IUDs. The copper IUDs comprise the second and the
hormone-releasing IUDs the third generation IUDs. The medicated
IUDs were developed to reduce the incidence of side-effects and to
increase the contraceptive effectiveness. However, they are more
expensive and must be changed after a certain time to maintain their
effectiveness .India, under the National Family Welfare Programme,
Cu-T-200 B is being used. From the year 2002, Cu-T -380 A has been
introduced in the programme .
131. Hormonal contraceptives currently in use and/or under
study may be classified as follows :
A. Oral pills
1. Combined pill
2. Progestogen only pill (POP)
3. Post-coital pill
4. Once-a-month (long-acting) pill
5. Male pill
B. Depot (slow release} formulations
1. Injectables
2. Subcutaneous implants
3. Vaginal rings
Classification
208. Definition :
A census is defined by the United
Nations as "the total process of
collecting, compiling and publishing
demographic, economic and social
data pertaining at a specified time or
times, to all persons in a country or
delimited territory"