1. Significance of Demographic transition in Public Health
Dr.Ayesha Babar Kawish

2. Demographic Transition
In 1929 the American demographer Warren Thompson, observed changes in birth and death rates in industrialized societies over the past two hundred years or so and then formulated a model called “Demographic Transition” that describes population change over time.

3. DEMOGRAPHIC STAGES
Describe changes in population size and composition due to increase or decrease in no of births and deaths

4. HIGH STATIONARY STAGE Birth rate is high, death rate high.
They nullify each other’s effect
no change in size of population.

5. STAGE 1 – HIGH STATIONARY
Birth Rate and Death rate both high.
Population growth is slow and fluctuating.
Reasons :
Birth Rate is high as a result of:
Lack of family planning
High Infant Mortality Rate
Need for workers in agriculture
Religious beliefs
Death Rate is high because of:
High levels of disease
Famine
Lack of clean water and sanitation
Lack of health care
Wars & Conflicts

6. STAGE 2 – EARLY EXPANDING
Death Rate begins to decline. Birth Rate remains unchanged. Population begins to rise steadily.
Reasons of decline in Death Rate:
Improved health care (e.g. Smallpox Vaccine)
Improved Hygiene (Water for drinking boiled)
Improved sanitation
Improved food production and storage
Improved transport for food
Decreased Infant Mortality Rates
Typical of Britain in 19th century;
Bangladesh; Nigeria
South Asia, Africa

7. LATE EXPANSION STAGE
Birth rate increase,
death rate decreases,
tremendous increase in population

8. STAGE 3 – LATE EXPANDING
Birth Rate tends to fall. Death Rate declines still further. Population continues to grow.
Reasons:
Family planning available
Lower Infant Mortality Rate
Increased mechanization reduces need for workers
Increased standard of living
Changing status of women
Typical of Britain in late 19th and early 20th century; China; Brazil, Pakistan.

9. LOW STATIONARY STAGE
Birth rate low,
death rate low,
Nullify each others effect.
no change in population size.

10. STAGE 4 – LOW STATIONARY
Birth Rate and Death Rate both low. Population becomes stationary like in industrialized nations.
Typical of USA; Japan; Britain
These changes are reflected in the population structure.

11. DECLINING STAGE
Birth rate lower than death rate.
Negative growth in population.

12. STAGE 5 – DECLINING
Birth rate lower than death rate.
Population starts declining.
Examples: Germany, Sweden and Hungry.
Negative Growth Rate.

13. Demographic Transition
Two demographic worlds Less-developed counties represent 80% of the world population, Richer countries tend to have negative growth rates.
Growth Rate (%)
Grading of population increase
0 ( Zero)
0 to 0.5
0.5 to 1
1 to 1.5
1.5 to 2.0
> 2
Stationary Growth (No Growth)
Slow Growth
Moderate Growth
Rapid Growth
Very Rapid Growth
Explosive Growth ( Population explosion) OR Population Bomb

14. DEMOGRAPHIC TRANSITION
3 TYPES
1. Old balance
Fertility Mortality
2. New balance
3. Imbalance

15. DEMOGRAPHIC TRANSITION
A look at global demographic situation suggests that some countries have passed through high fertility and high mortality condition to a low fertility and mortality condition both aiming at low growth of population. These two conditions are referred as old & new balance, with an in-between period of imbalance as described below:
OLD BALANCE
HIGH FERTILITY
HIGH MORTALITY
(POOR HEALTH CONDITION ,
NOT COMPFORTABLE LIFE STYLE)
LOW FERTILITY
NEW BALANCE
LOW MORTALITY
GOOD HEALTH CONDITIONS, COMFORTABLE LIFE STYLE
HIGH FERTILITY
IMBALANCE
LOW MORTALITY
(PERIOD OF RAPID NATURAL INCREASE)

17. This growth is helpful for under populated nations which needs more manpower, expanding markets ; however it eventually results in too fast growth of population leading to economic, political and social chaos. a no. of developing countries e.g. Pakistan & many African countries are in this phase of demographic transition
(Late Expanding)

18. Demographic gap is the difference between birth rate and death rate that develops when a country undergoes demographic transition
In a demographic cycle, as the country develops and the living conditions improve, there is first a decrease in the death rate in the population But the birth rate continues to remain at a high level
This results in a demographic gap and a resultant increase in the total size of population
The demographic gap is maintained till the birth rate and death rates become equal and the population size becomes stable

20. Population Pyramids ( Demographic Transition Models)
Stage 1
Stage 2
Stage 3
Stage 4
High stationary
Early expanding
Late expanding
Late stationary
IMPLICATIONS
Both birth rates and
Death rates are High
population
growth rates are
slow but
population Is usually restored Due to high birth rate. Short life expectancy
Population starts
to grow at an
exponential rate due to fall in Crude Death Rate. More living In middle age.
Life expectancy rises
Infant mortality rate falls.
Population continues
to grow but at slower
rate. Low C Death Rate.
Dramatically declining
Crude Birth Rate.
Low Crude Birth Rate
and Crude Death Rate
Higher dependency ratio
and longer life expectancy
Crude Death Rate does
Rise slightly because of
The ageing population
Scotland today.
Japan, USA
Scotland
Algeria, Tunisia
Morocco
Scotland before 1760
New Guinea
Remote parts of
Amazonia
Scotland
Republic of Congo
There is some merit in including or considering
a Stage 5 today with a declining population

21. According to Malthusian theory of population increase population increase in geometric ratio where as food supply increase in arithmetic ratio. This disharmony would lead to widespread poverty and starvation which would only be checked by natural occurrences such as disease, high infant mortality, famine, war or moral restraint. His main contribution is in the agricultural sector. According to this theory there are two steps to control the population, PREVENTIVE AND POSITIVE CHECK. preventive means control in birth rate, use of different methods to control birth and positive check means natural calamities, war etc.
Arithmetic = 1,2,3,4,5 or 2,4,6,8, , 6, 9, sequence
Geometric= 1,2,4,8,16, ,8,4,2,1,1/ ratio difference

23. DEMOGRAPHIC CYCLE Germany, Hungary (after effect of India in 1920-1930
Population
Grows rapidly
Germany,
Hungary (after effect of
II world war)
India in
Population
Becomes stationary
Population
Grows slowly
Population
declines
Population
stationary
Many countries of S. Asia & Africa
China,
Singapur
Pak in 1970

24. Demographic Transition Accompanying Economic and Social DevelopmentB
Birth Rate
Death Rate
In the above graph, you can see there are distinctive periods of transitions associated with population stabilization. For instance, in pre-development periods, when there is a lack of medicine or mechanized agriculture, food often limits population growth. In these periods, there is a very high death rate (about 30 per 1,000 people), which includes people who die before they have a chance to reproduce. So a high birth rate is required to keep the population size stable.
In the next phase, shown in the second column of the graph, a society develops better medical care and sanitation, and the death rate starts to fall. More people live into their reproductive years, so the birth rate remains high and may even increase. In the third phase, the death rate stabilizes and birth rates start to drop. The birth rate may drop for a variety of reasons - women have more access to education, or governments promote family planning, for example. Also, as a society industrializes, the labor of children is no longer needed to help the family survive, and there are other ways for people to be cared for in their old age than through their children. In the last phase of transition, represented by "developed" countries, birth and death rates stabilize. Notice, though, that the population size is greater overall than in the predevelopment phase.
If an ever-increasing population is a societal ill, then theoretically the birth rate can adjust back down to where the population will again be stable.

27. Population Momentum
The tendency of a population to continue to grow after replacement-level fertility has been achieved. A population that has achieved replacement or below replacement fertility may still continue to grow for some decades because past high fertility leads to a high concentration of people in the youngest ages. Total births continue to exceed total deaths. As these youth become parents. Thus it may take two or three generations (50-70 years) before each new birth is offset by a death in the population.

28. DEMOGRAPHIC TRAP
Country with high population growth --high birth rate and low death rate.
When a developing country moves into the 3rd stage of transition---death rates < 10/1000 people.
Country’s economic growth unable to support needs of exploding population instead of economic development.
Country cannot proceed onward to the final stage of post transition.

29. DEMOGRAPHIC WINDOW
Period of time when the working age group population is particularly prominent.
This window of opportunity lasts for 3-4 decades.
Birth rates fall, age pyramid shrinks with lower proportions of young population (< 15s ) and dependency ratio decreases, e.g., as in East Asia.
After a few decades, low fertility causes population to get older & thereby inflate the dependency ratio, e.g. as in Europe today.

30. ii) Percentage distribution of population by age-sex-location are helpful in understanding health and health care needs of various age groups by sex by location, for planning, designing, evaluation and effective implementation of various public health programs. For example : Vaccination and immunization program for children under 5 years of age, Mother and Child Health program for mother and new born, Family planning program, old age program, nutritional program etc.

31. iii) Determining the success or failure of health programs.
iv) To describe the level of community health.
v) To determine the leading causes of mortality and morbidity.

32. vi) To determine the relative importance of different fatal diseases with respective to age and sex.
vii) To discover solution to health problems and find clues for public health challenges.

33. Thankyou