L2 Environment_Health_Disease_Concepts-1.ppt

ENV
101
Lecture
2
Concepts: Environment,
Health and Disease
1

Introduction
2
• Our environment affects our health
• Many factors in the environment may have negative
or positive impact on people’s health and welfare
• Human activities may also affect the environment
• The quality of environment in which a person lives,
is linked with the quality of life he/she enjoys
especially socio-economic status
• Therefore, to enjoy good health a safe and healthy
environment necessary

• The physical and social conditions in which people
live especially as they influence their feelings and
development. It includes natural conditions e.g. air,
water, land and energy in which organisms live
• The sum total of all conditions and influences that
affect the development of all living things including
man. It includes the positive and negative effects of
human intervention and creation of assets or
capital
3
Definitions of Environment

• Last (Dictionary of Epidemiology) defines the
environment as 'all that is external to the human
host‘. It can be divided into physical, biological,
social, and cultural factors, any or all of which can
influence health status in populations
• It can be taken to include anything except genetic
factors
• Things in the natural environment like air, water and
soil, and also all the physical, chemical, biological
and social features of our surroundings
4

• The atmosphere, milieu, or conditions in which an
individual lives, works, or plays
• The circumstances, objects, or conditions by which
one is surrounded. The complex of climatic, edaphic
(soil-based), and biotic factors that act upon an
organism or an ecologic community
• A conventional definition of the term ‘environment’ is
‘immediate surroundings; all the conditions,
circumstances and influences surrounding and
affecting all organisms or a group of organisms’
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• To an environmentalist, environment comprises the
land, water, air and other physical structures
observable around an organism or a group of
organisms.
• From an ecological viewpoint, environment is simply
an ecosystem
• The following illustration is a good representation of
environment:
Environnent = Natural Environnent + Man-made
Environnent + Social Environment
6

• An ecological definition of the environment is
necessary for a clearer and better understanding of
the relationship of environment to human health
• An ecosystem refers to any natural or artificial
environment where living things interact with non-
living things
• Thus, man as a unit within an ecosystem interacts
with, and is dependent on other living things as well
as the physical, chemical and socio-cultural factors
in the ecosystem
7

Components (Natural Environment)
• An environment that is as close as possible to its natural
state – one that is relatively unaffected by human activity
• Comprises all living and non-living things that occur naturally
on earth or some part of it. Key components:
a. Complete landscape units that function as natural
systems without massive human intervention, including all
plants, animals, rocks, etc. and natural phenomena that
occur within their boundaries
b. Universal natural resources and phenomena that lack
clear-cut boundaries, such as air, water and climate.
c. Natural features which occur within areas heavily
influenced by man (such as wild birds in urban gardens)
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The natural environment may be described as
consisting of the atmosphere, hydrosphere,
lithosphere and biosphere
LITHOSPHERE
• The earth’s crust consisting of the soil and rocks is
the lithosphere. The soil is made up of inorganic
and organic matter and water
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HYDROSPHERE
• This comprises all water resources both surface and
ground water
• The water locked up in the Oceans and Seas are
too salty and cannot be used directly for human
consumption, domestic, agriculture or Industrial
purposes
• Only less than 1% of water resources are available
for human exploitation
10

BIOSPHERE
• The biosphere is a capsule encircling the earth’s
surface wherein all the living things exist
• This portion extends from 10000 m below sea level
to 6000 m above sea level
• Life forms do not exist outside this zone
• The biosphere covers parts of other segments of
the environment viz. Lithosphere, Hydrosphere and
Atmosphere
11

ATMOSPHERE
• The gaseous envelope surrounding the earth and
extends up to 500 kms above the earth’s surface
• Protects the earth from cosmic radiations
• Provides life sustaining Oxygen, the macronutrient
Nitrogen and Carbon dioxide needed for
photosynthesis
• Has four major zones viz. Troposphere,
Stratosphere, Mesosphere and Thermosphere
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Inter-relationship between the components and
subcomponents
13

Components (Man-made Environment)
• Referred to as the built environment, comprises
areas and components that are heavily influenced
by man
• Includes physical structures where people live and
work e.g. homes, offices, schools, farms and
factories, as well as community systems e.g. roads
and transportation systems, land use practices and
waste management
• Consequences of human alteration to the natural
environment, e.g. air pollution, are also parts of the
man-made environment
14

Components (Social Environment)
• The social environment encompasses lifestyle
factors like diet and exercise, socioeconomic
status, and other societal influences that may affect
health
15

Major Components of Environment
Major components include:
• Air
• Water
• Land
• Energy
• Living Organisms
16

Inter-relationship of Components
• Living beings are dependent upon their physical
environment - the land, water, air and energy for
their existence
• The changed physical conditions again have a
direct impact on living beings
• A fundamental aspect in ecology that helps us
understand the inter-relationship between plants
and animals, animals and animals, animals and
human beings is their requirement of food
17

• Growing urbanization, rapid industrialization,
intensive cultivation, population explosion and the
human desire to live a more comfortable life have
degraded the 'biosphere'.
• Thus, the strong need to care for our environment to
avoid unprecedented havoc around the globe and
ensure continued existence of man and other living
and non-living organisms.
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Why should we Care for our Environment?

Trends in Environment and Health Concerns
• 1952 London smog as a result of the build up of
sulphurous air pollution
• 1956 episode of organic mercury poisoning in
Minamata, Japan.
• 1984 Bhopal disaster, in the Indian state of Madhya
Pradesh due release of 40 tonnes of methyl
isocyanate gas
• 1986 Chernobyl nuclear accident which resulted in
the release of a plume of radioactive dust
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Industrialization and Urbanization
• Industrial development and urbanization has been a
major and continuing global trend
• Half of all people now live in urban environments
• Urban life is often polluted and unhealthy, especially
in low income countries
• Large cities in the poorer countries typically
combine the environmental problems of poverty
with those of uncontrolled urban expansion,
squatter settlements and unregulated
industrialization
20

Residents therefore often face the combined hazards
of:
• Poor sanitation
• Unsafe drinking water
• Precarious housing
• Dangerous roadways
• Polluted ambient and indoor air, and
• Toxic wastes
21
Industrialization and Urbanization

Global Environmental Change
• Human activity is now giving rise to a set of large-
scale environmental problems, with capacity to
cause adverse effects at a global scale e.g.:
o reducing biodiversity at unprecedented speed,
o depleting non-replenishable resources
o altering the gaseous composition of the lower and
middle atmosphere.
• Among the more prominent effects with potential
bearing on human health are:
o global climate change
o stratospheric ozone depletion
22

• Global change should be distinguished
from globalization, which refers to the processes that
lead to increasing flows of people, goods, information
and ideas across the world
• Globalization is itself an important influence on health
because of its bearing on such factors as:
o the spread of (transmissible) disease
o the export from high to lower income countries of
occupational exposures
o the economic factors that contribute to health
inequalities and unhealthy patterns of production
and consumption
23
Global Environmental Change

Some of the major environmental concerns facing the world today
include:
• Greenhouse effect and global warming
• Ozone depletion
• Urbanization and its associated problems
• Degradation of land
• Air and water pollution
• Loss of biological diversity
• Large scale deforestation
• Depletion of natural resources
• Disposal of waste
24
Global Environmental Problems

Global Burdens of Disease (environmental)
• Estimates suggest that between a quarter and a third
of the global burden of disease and premature death
is attributable to direct environmental risk factors
• The international Global Burden of Disease initiative
has attempted to derive estimates of mortality and
disability adjusted life years (DALYs) for selected
causes ( see table)
• For the environment they indicate that the largest
burdens globally arise from unsafe water, sanitation,
indoor smoke, outdoor air pollution
25

Global Burden of Disease: annual mortality and DALYs (millions) for
selected causes
Mortality DALYs
Childhood and maternal under-nutrition 6.16 227.5
Environmental
Unsafe water, sanitation & hygiene
1.73 54.1
Urban outdoor air pollution 0.81 6.4
Indoor smoke from solid fuels 1.62 38.5
Global climate change 0.15 5.5
Total for all causes 55.9 1,455
Source. Ezzati et al., Lancet 2002 ; 360:1347-60
26

Environmental Justice
• Socio-economic deprivation is important as a
frequent determinant of environmental exposures
• Poorer people are more vulnerable to the effects of
environmental exposures due to their health status
and inadequate access to services
• Such people consume fewer resources and are
responsible for fewer resources
27

This is often labelled the issue of environmental
justice (or injustice). Examples include:
• Exposure to road traffic: poorer people tend to have
poorer access to cars, but are often more exposed
to traffic-related emissions
• Climate change: those in the richer countries are
larger per capita contributors to the problem, yet the
burdens are likely to be greatest in low-income
countries
28
Environmental Justice

Environmental Risks & Development
(Kuznets’ Curve)
• For many environmental pollutants, exposures tend to
follow an inverted-U trajectory over time
• This is sometimes referred to as the 'environmental
Kuznets' curve (see figure)
• Low income populations tend to suffer most from
households exposures
• Middle income populations on the other hand suffer
more from community-level pollution
• High income populations have, for the most part,
reduced these risks, but contribute disproportionately to
global problems
29

What is Health
• Health is a state of complete physical, mental and
social well-being and not merely the absence of
disease or infirmity
• An experience that is often expressed in terms of
wellness and illness and that may occur in the
presence or absence of disease or injury
• The condition of being sound in body, mind, or
spirit
31

• The enjoyment of the highest attainable standard of
health is one of the fundamental rights of every
human being without distinction of race, religion,
and political belief, economic and social isolation
• The health of all people is fundamental to the
attainment of peace and security and is dependent
upon the fullest cooperation of individual states
32
What is Health

Dimensions of Health
• A holistic dimension
• A positive dimension
• A negative dimension
33

A Holistic Dimension of Health
• A Holistic concept of health is the belief that being
healthy means being without any physical disorders or
diseases and being emotionally comfortable
• Generally, people with this view are likely to label
themselves as ill when they experience a wide range of
unpleasant feelings, not just physical discomfort or pain
• E.g., a person who feels anxious or has low self-esteem
would, according to this concept, not be well
• Likewise, a person with malaria or chickenpox is likely
to label himself/herself ill
34

Advantages
• The holistic concept is that tends to make people
sensitive about their health
• It can encourage people to eat healthy and live
healthy
35

Disadvantages
• It can lead to oversensitivity to signs and symptoms
of illness, i.e. lead people to believe that they are ill
when they are not
• It can lead to unnecessary worry and result in people
wasting their Doctor’s time.
• It can also result in people not leading a lifestyle that
is good for their health, such as going to work,
taking strenuous exercise and going on holiday.
36

A Positive Dimension of Health
• A positive dimension of health is the belief that being
healthy is a state achieved only by continuous effort
• Such people are likely to feel responsible for their own
health
• They will take credit for the continued absence of
disease and blame themselves if they develop
symptoms
• According to this view, people who do not take action
to maintain their own health (e.g., by ‘healthy eating’)
cannot be healthy — even if, at any one time, there is
nothing wrong with them
37

Advantages
• Such people usually indulge in attitudes that enhance
health
• If they become ill, they are likely to adopt attitudes and
behavior that contribute to getting better
• People who believe they can recover and avoid feeling
defeated by their illness tend to do better than those
who believe that they are doomed to die
• People with positive dimensions to health tend to be
active rather than passive in relation to their own health
38

Disadvantage
• One disadvantage of this concept is that, by taking
responsibility for their own health, people might
blame themselves for their illnesses and feel guilty
when they become ill
39

A Negative Dimension of Health
The view that being healthy is the absence of illness. People
with this view are likely to believe that good health is normal
and take it for granted
Advantage: A person with this perspective may be less
anxious about his/her health
Disadvantage
• A person with this concept believes that being healthy is by
chance, may therefore think less of healthy habits as well as
measures to live healthy
• He/she may engage in self medication because good health
is taken for granted
40

Defining Disease
• Pathology is the study of diseases
• The subject of systematic classification of diseases
is referred to as nosology
• The broader body of knowledge about human
diseases and their treatments is medicine
• Many similar (and a few of the same) conditions or
processes can affect animals (wild or domestic)
• The study of diseases affecting animals is
veterinary medicine
41

• A disease is a change away from a normal state of health to
an abnormal state in which health is diminished
• Disease is also a medical condition. It is an abnormality of
the body or mind that causes discomfort, dysfunction,
distress, or death to the person afflicted or those in contact
with the person
• Sometimes the term is used broadly to include injuries,
disabilities, disorders, syndromes, infections, symptoms,
deviant behaviors, and atypical variations of structure and
function, while in other contexts these may be considered
distinguishable categories
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Defining Disease

• Specific kinds of biological reactions to some kind of
injury or change affecting the internal environment
of the body
• Trouble or a condition of the living animal or plant
body or one of its parts that impairs the
performance of a vital function
• Illness: the subjective experience of discomfort
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Defining Disease

References
• Last, J. M. (Ed.). (1995). A Dictionary of Epidemiology (3rd ed.). New
York: Oxford University Press
• http://www.natural-environment.com/
• http://www.yourarticlelibrary.com/environment/meaning-definition-and-
components-of-environment/6157/
• CHP-1.PM5. Components and subcomponents of environment
44

L2 Environment_Health_Disease_Concepts-1.ppt

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