2. THEHEALTH
TRANSITION
Health transition: the shifts that have taken place
in the patternsand causesof death.
The health transition has been covered by two
separate terms:
Demographic transition
Epidemiological transition
3. DEMOGRAPHIC
TRANSITION
A change in the population dynamics of a
country as it moves from
HIGH FERTILITYAND MORTALITYRATES
LOW FERTILITYAND MORTALITY RATES
4. INDICATORSFORPOPULATION
Age dependency ratio
The dependency ratio relates the number of children (0-14 years
old) and older persons (65 years or over) to the working-age
population (15-64 years old).
Child dependency ratio
(%age of 0-14 Yrs. age group/ working-age population 15-64 Yr
.
x 100)
Old dependency ratio
(%age of 65 and above Yrs. age group/ %age of15-64 Yr x 100)
Sex ratio
The sex ratio is the ratio of males to females in the population
Life expectancy:the average period that a person may
expect to live
life expectancy of male is Pakistan is 66 years and 67 years for
female
5. POPULATIONPYRAMID
Itis a diagram that gives information about
proportion of males / females in each age group
proportion of young people (0 -14 )
proportion of working people (15 –59)
proportion of elderly people (60+)
Shape of pyramids is controlled by
births
deaths
migrations
6.
7.
8. BROAD-BASED PYRAMID
Shape: Broad Base - high birth rates
Narrow Top - small elderly pop
- high death rate
Proportion: - Large proportion of young
- high young dependency ratio
Sex Ratio: Balance pyramid - Balance sex
9. BEEHIVE-SHAPEDPYRAMID
Shape: Rocket-shaped / Narrow Base
Low Birth Rates, Slow pop growth
Proportion: Large proportion of working
population, 15-59 yr. old - large
group of economically active pop
Sex Ratio: Balanced pyramid
10. RECTANGULARPYRAMID
Shape: Rectangular-shaped - Zero Pop Growth
Narrow Base - Low Birth Rates
- Life-expectancy is high e.g. 80+
- Low death rates
Proportion: Bars of equal length - Balance Proportion
Sex Ratio: Balance pyramid - Balance Sex Ratio
11.
12. FACTORSAFFECTINGPOLLUTION
CHANGES
• POPULATION GROWTH RATE:
• Refers to the rate, at which a given population is
increasing at a given period of time, it is given in
percentage per year.
• POPULATION DOUBLING TIME:
• Refers to the time that would take for a population to
double. Formula
• is 70 divided by the population % increase per
year
• NET MIGRATION:
• Refers to the total number of persons added or
subtracted from a population as a result of the
combined effect of immigration &
emigration.NET MIGRATION = (In migration – out
13.
14.
15. EPIDEMIOLOGICTRANSITION
THEORY
Formulated by epidemiologist Abdel Omran in
1971.
It comprisesthree stages characterized by
fertilitylevels and causes of death
The age of Pestilence and famine
The age of Receding pandemics
The age of Chronic diseases
16. THEORYOF EPIDEMIOLOGIC
TRANSITION
1. Mortality isa fundamental factor in population
dynamics.
2. During the transition, a long-term shift occurs in
mortality and disease patterns where Communicable
Pandemics are gradually displaced by Chronic
diseases.
3. Most changes are among children and young women.
4. The shiftsare closely associated with the demographic
and socioeconomic transitions that constitute the
modernization complex.
5. Unusual variations in the pattern, the pace, the
determinants and the consequences of population
change differentiate three basic models of the
epidemiologic transition.
17.
18. DEMOGRAPHIC
TRANSITION
DEVELOPED VS. DEVELOPING NATIONS
All industrialized nations have gone through these
phases of demographic transition.
The developing nations have completed Phase I
and are currently in Phase II-a phase of
explosive rates of natural increase.
Countries in western Europe took roughly 200
years to complete their transitions.
19. EPIDEMIOLOGIC
TRANSITION
A characteristic shift in the disease pattern of a
population as mortality fallsduring the
demographic transition:
Acute infectious diseasesare reduced,
While chronic, degenerative diseases increase in
prominence,
Causing a gradual shift in the age pattern of
mortality from younger to older ages
22. Age of pestilence and
famine
Age of receding pandemics
Age of chronic
diseases
Increased economic growth
improves use of ecological
resources and provides
basic social services
Improved medical care
and social determinants
influences health
LIFE
EXPECTAN
CY
Time
Poor use of
ecological resources
and lack of social and
economic capital
Heahlth
Health
Health
23. FIRSTEPIDEMIOLOGICAL
TRANSITION
The First Epidemiological T
ransition occurred 100
centuries ago when man moved towardsthe
agricultural society.
By avoiding the nomadic lifestyle, people stayed
in one place and increased theircontact with
human (and animal) waste, and contaminated
their water supplies.
And even the cultivation of soil, and the clearing
of land, exposed people to insect bites,
bacteria, and parasites.
Ascities grew, and exploration of the
surrounding world increased, man spread deadly
diseases in ever-greater numbers.
24. FIRSTEPIDEMIOLOGICAL
TRANSITION
This epidemiological transition was described as
“the age of pestilence and famine"
Epidemic, faminesand wars caused huge
numbersof deaths.
Infectiousdiseaseswere dominant, causing high
mortality rates, especially among children.
25. FIRSTEPIDEMIOLOGICAL
TRANSITION
Plague –The Black Death.
The first recorded case of the plague was in
China in 224 B.C.
But the most significant outbreakwas in Europe in
the mid-fourteenth century.
Over a five-year period from 1347 to 1352, 25
million people died.
One-third to one-half of the European population
was wiped out.
26. FIRSTEPIDEMIOLOGICALTRANSITION….
High levels of mortality and fertility.
Crude Death Rate (CDR) ishigh and ranges from 30
to over 50 deaths per 1,000 population.
Infant mortality rate 200-300 deaths per 1,000 live
births.
Life expectancy between 20-40 years.
T
he provision of basic ecological resources, i.e. food
and fresh water
, was inadequate.
There was lack of sufficient infrastructure for most
services.
Population growth, improvements in health, and
advances in socio-economic development were all
limited by the local carrying capacity of the
environment.
27. SECOND EPIDEMIOLOGICAL
TRANSITION
The Second Epidemiological T
ransition
began roughly 200 years ago, with the
Industrial revolution.
While many of the existing diseases
brought forth during the first transition
certainly did not go away, new-
chronic, non- infectious, degenerative
diseases –were added to the mix.
This phase was described as
“age of receding pandemics”
It involved a reduction in the
prevalence of infectious diseases, and
a fall in mortality rates.
28. SECOND
EPIDEMIOLOGICAL
TRANSITION
CDR reachesa level of lessthan 30 deaths per
1,000 population.
IMR was 150 per1,000 live births.
Asa consequence,life expectancy at birth
climbed rapidly from about 35 to 50 years.
Increased economic growth led to sharp fall in
deaths from infectious diseases, and from
malnutrition.
This Improvement occurred before effective
medical treatment and was due to impact of
interventions
31. SECOND
EPIDEMIOLOGICAL
TRANSITION
Finally, the introduction of modern healthcare
and health technologies, e.g.
🞑 immunization programs
🞑 introduction of antibiotics
Enabled the control and elimination of group of
infectious diseases such as Diphtheria, polio and
smallpox.
32. SECOND
EPIDEMIOLOGICAL
TRANSITION
As fertility rates were high, population was
growing rapidly at this stage of the health
transition. Without moving to the next stage, the
carrying capacity of the local ecosystem may be
exceeded.
Aspopulation and ecological pressures
increased, food and water became scarcer, and
the lack of ecological and social resourcesmay
cause economic development to stagnate.
If there isa surplus of available resources, the
transition may be accelerated, but if they are
lacking, the transition may slow, or even stagnate
in this phase.
33. THIRDEPIDEMIOLOGICAL
TRANSITION
Began in the late 20th century.
This phase was described as
‘The age of chronic diseases’
In the third stage the elimination of
infectious diseasesmakesway for
chronic diseasesamong the elderly.
The major causes of death are so-
called chronic degenerative and
man- made diseasessuch as
cardiovascular diseases, cancer,
and diabetes.
36. THIRDEPIDEMIOLOGICAL
TRANSITION
While improved healthcare means that these
are less lethal than infectious diseases, they
nonetheless cause relatively high levels of
morbidity.
Increasingly, health patterns depend on social
and cultural behavior
.
Due to low levels of mortality and fertility,
there islittle population growth.
CDR stabilizes at a level of less than 20 deaths
per 1,000 population
By the end of the third stage, infant mortality
reaches a level of less than 25 deaths per
1,000 live births.
When the health transition is at an advanced
stage, life expectancy may exceed 80 years.
37. EXCEPTIO
NS
Though the struggle against infectious diseases,
especially tropical diseases, was at first successful,
some countries, mainly in Africa, were unable to
reach a pace of progresssufficient to reduce the
gap separating them from developed countries.
The arrival of AIDSoften caused severe reversals
and towardsthe end of the 1980s, life
expectancy levels suddenly dropped.
40. FUTURESTAGES OFTHE
EPIDEMIOLOGICAL
TRANSITION
Martens (2002) described the developments in
the health status of populations according to
three potential future 'ages
“the age of emerging infectious diseases”
“the age of medical technology”
“the age of sustained health”
41. THEAGE OF EMERGING
INFECTIOUS DISEASES
In this stage, the emergence of new infectious
diseases or the re-emergence of 'old' ones will
have a significant impact on health.
A numberof factorswill influence this
travel and trade
microbiological resistance
human behavior
breakdowns in health systems
increased pressure on the environment
42. THEAGE OF EMERGING
INFECTIOUS DISEASES
The overuse of antibiotics and insecticides,
combined with inadequate or deteriorating
public health infrastructures will hamper or delay
responses to increasing disease threats.
As a result, infectious diseases will increase
drastically, and life expectancy will fall
Ill health will lead to lower levels of economic
activity, and poor countries will be caught in a
downward spiral of depressed incomesand bad
health.
Control of infectious diseaseswill be hampered by
political and financial obstacles, and by an
inability to use existing technologies
43. THEAGE OF MEDICAL
TECHNOLOGY
To a large extent, increased health riskscaused
by changes in life-style and environmental
changes will be offset by increased economic
growth and technology improvements in the age
of medical technology.
If there isno long-term, sustainable economic
development, increased environmental pressure
and social imbalance may propel poorsocieties
into the age of emerging infectious diseases
44. THEAGE OF SUSTAINED
HEALTH
In the age of sustained health, investmentsin
social services will lead to a sharp reduction
in life-style related diseases, and most
environmentally related infectiousdiseases
will be eradicated.
Health policieswill be designed to improve the
health status of a population in such a way
that the health of future generations isnot
compromised by, for example, the depletion of
resources needed by future generations.
45. THEAGE OF SUSTAINED
HEALTH
Although there isonly a minimal chance that
infections will emerge, improved worldwide
surveillance and monitoring systemswill mean
that any outbreakis properly dealt with.
Despite the ageing of the world population,
health systemswill be well adjusted to an older
population.
Furthermore, disparities in health between rich
and poor countries will eventuallydisappear.
46. EPIDEMIOLOGICAL TRANSITION
DEVELOPED/ DEVELOPING
COUNTRIES
• Developed
•
Curre
ntly, most
developed countries
are in the third stage
of the health
transition:
• Fertility rates are
low
• Causes
of diseases and
deaths have shifted
from infectious
Developing
T
he health situation in
developing countries
varies greatly from one
country to another.
In most, there isstill very
low life expectancy;
this isdue largely to
malnutrition and the
lack of safe drinking
water, which are
compounded by poor
healthcare facilities
47.
48. CONCLUSI
ON
Nevertheless, it isgenerally believed that the
epidemiologic transition theory presents a broad
conceptual framework that isuseful for the study
of global trends in disease and mortality.
“the epidemiologic transition theory provides a
potentially powerful framework for the study of
disease and mortality in populations, especially
for the study of historical and international
variations”. Mackenbach (1994)
49. WHEREAREWE RIGHTNOW?
Crude mortality rate has been declined to
6.8/1000
Life expectancy is66 years
In 1990:
Communicable diseases accounted for 60%of
deaths
The NCDs accounted for26%of the deaths
In 2018:
NCDs have overtaken infectious diseases and
account for56%of deaths.
