Unit I: Health and Disease

CONCEPT OF HEALTH
Health has evolved over the centuries as a concept
from an individual concern to a worldwide social
goal and encompasses the whole quality of life.
– Biomedical concept : Traditionally, health has been
viewed as an "absence of disease", and if one was free
from disease, then the person was considered healthy.
This concept, known as the "biomedical concept" has
the basis in the "germ theory of disease" which
dominated medical thought at the turn of the 20th
century. The medical profession viewed the human
body as a machine, disease as a consequence of the
breakdown of the machine and one of the doctor's
task as repair of the machine.

• Ecological concept : Deficiencies in the
biomedical concept gave rise to other
concepts. The ecologists put forward an
attractive hypothesis which viewed health as a
dynamic equilibrium between man and his
environment, and disease a maladjustment of
the human organism to environment. Dubos
defined health saying : "Health implies the
relative absence of pain and discomfort and a
continuous adaptation and adjustment to the
environment to ensure optimal function".

• Psychosocial concept : Contemporary
developments in social sciences revealed that
health is not only a biomedical phenomenon,
but one which is influenced by social,
psychological, cultural, economic and political
factors of the people concerned. These factors
must be taken into consideration in defining
and measuring health. Thus health is both a
biological and social phenomenon.

• Holistic concept: The holistic model is a synthesis of all
the above concepts. It recognizes the strength of social,
economic, political and environmental influences on
health. It has been variously described as a unified or
multidimensional process involving the well-being of
the whole person in the context of his environment.
This view corresponds to the view held by the ancients
that health implies a sound mind, in a sound body, in a
sound family, in a sound environment. The holistic
approach implies that all sectors of society have an
effect on health, in particular, agriculture, animal
husbandry, food, industry, education, housing, public
works, communications and other sectors

DEFINITION OF HEALTH
• WHO definition
The widely accepted definition of health is that given by the
World Health Organization (1948) in the preamble to its
constitution, which is as follows :
"Health is a state of complete physical, mental and social well-
being and not merely an absence of disease or infirmity"
In recent years, this statement has been amplified to include
the ability to lead a "socially and economically productive
life".
The WHO definition of health has been criticized as being too
broad. Some argue that health cannot be defined as a
"state" at all, but must be seen as a process of continuous
adjustment to the changing demands of living and of the
changing meanings we give to life. It is a dynamic concept.
It helps people live well, work well and enjoy themselves

• Operational definition of health
"operational definition" has been devised by a
WHO study group. In this definition, the
concept of health is viewed as being of two
orders. In a broad sense, health can be seen as
'·a condition or quality of the human organism
expressing the adequate functioning of the
organism in given conditions, genetic or
environmental".

• In a narrow sense - more useful for measuring
purposes - health means:
– there is no obvious evidence of disease, and that a
person is functioning normally, i.e. , conforming
within normal limits of variation to the standards
of health criteria generally accepted for one's age,
sex, community, and geographic region; and
– the several organs of the body are functioning
adequately in themselves and in relation to one
another, which implies a kind of equilibrium or
homeostasis - a condition relatively stable but
which may vary as human beings adapt to internal
and external stimuli.

New philosophy of health
In recent years, we have acquired a new philosophy of
health, which may be stated as below :
- health is a fundamental human right
- health is the essence of productive life, and not the
result of ever increasing expenditure on medical care
- health is intersectoral
- health is an integral part of development
- health is central to the concept of quality of life
- health involves individuals, state and international
responsibility
- health and its maintenance is a major social investment
- health is a worldwide social goal.

DIMENSIONS OF HEALTH
• Health is multidimensional.
• The WHO definition envisages three specific
dimensions - the physical, the mental and the
social.
• Many more may be cited, viz. spiritual,
emotional, vocational and political
dimensions.
• As the knowledge base grows, the list may be
expanding.

• Physical dimension
– The state of physical health implies the notion of '·perfect
functioning" of the body.
– It conceptualizes health biologically as a state in which every cell
and every organ is functioning at optimum capacity and in
perfect harmony with the rest of the body.
– The signs of physical health in an individual are: "a good
complexion, a clean skin, bright eyes, lustrous hair with a body
well clothed with firm flesh, not too fat, a sweet breath, a good
appetite , sound sleep, regular activity of bowels and bladder
and smooth, easy, coordinated bodily movements. All the
organs of the body are of unexceptional size and function
normally; all the special senses are intact; the resting pulse rate,
blood pressure and exercise tolerance are all within the range of
"normality'' for the individual's age and sex. In the young and
growing individual there is a steady gain in weight and in the
future this weight remains more or less constant at a point
about 5 lbs (2.3 kg) more or less than the individual's weight at
the age of 25 years.

• Mental dimension
Mental health is not mere absence of mental
illness. Good mental health is the ability to
respond to the many varied experiences of life
with flexibility and a sense of purpose. More
recently, mental health has been defined as "a
state of balance between the individual and
the surrounding world, a state of harmony
between oneself and others, a coexistence
between the realities of the self and that of
other people and that of the environment"

• characteristics as attributes of a mentally healthy
person:
– a mentally healthy person is free from internal
conflicts; he is not at "war" with himself.
– he is well-adjusted, i.e., he is able to get along well
with others. He accepts criticism and is not easily
upset.
– he searches for identity.
– he has a strong sense of self-esteem.
– he knows himself: his needs, problems and goals (this
is known as self-actualization).
– he has good self-control-balances rationality and
emotionality.
– he faces problems and tries to solve them intelligently,
i.e., coping with stress and anxiety.

• Social dimension
Social well-being implies harmony and
integration within the individual, between
each individual and other members of society
and between individuals and the world in
which they live. It has been defined as the
"quantity and quality of an individual's
interpersonal ties and the extent of
involvement with the community''

• Spiritual dimension
Proponents of holistic health believe that the time
has come to give serious consideration to the
spiritual dimension and to the role this plays in
health and disease. Spiritual health in this
context, refers to that part of the individual which
reaches out and strives for meaning and purpose
in life. It is the intangible "something" that
transcends physiology and psychology. As a
relatively new concept, it seems to defy concrete
definition. It includes integrity, principles and
ethics, the purpose in life, commitment to some
higher being and belief in concepts that are not
subject to "state of the art'' explanation

• Emotional dimension
Historically the mental and emotional dimensions
have been seen as one element or as two closely
related elements. However, as more research
becomes available a definite difference is
emerging. Mental health can be seen as
"knowing" or "cognition" while emotional health
relates to "feeling". Experts in psychobiology have
been relatively successful in isolating these two
separate dimensions. With this new data, the
mental and emotional aspects of humanness may
have to be viewed as two separate dimensions of
human health

• A few other dimensions have also been suggested
such as:
philosophical dimension
cultural dimension
socio-economic dimension
environmental dimension
educational dimension
nutritional dimension
curative dimension
preventive dimension.

SPECTRUM OF HEALTH
• Health and disease lie along a continuum, and
there is no single cut-off point.
• The lowest point on the health-disease
spectrum is death and the highest point
corresponds to the WHO definition of positive
health.

• The spectral concept of health emphasizes that
the health of an individual is not static; it is a
dynamic phenomenon and a process of
continuous change, subject to frequent subtle
variations.
• What is considered maximum health today may
be minimum tomorrow. That is, a person may
function at maximum levels of health today, and
diminished levels of health tomorrow.
• It implies that health is a state not to be attained
once and for all, but ever to be renewed. There
are degrees or "levels of health" as there are
degrees or severity of illness. As long as we are
alive there is some degree of health in us.

Determinants of Health

Epidemiological triad

Natural History of disease

MODES OF INTERVENTION
• defined as any attempt to intervene or interrupt
the usual sequence in the development of
disease in man. This may be by the provision of
treatment, education, help or social support.
– Health promotion
– Specific protection
– Early diagnosis and treatment
– Disability limitation
– Rehabilitation

Health promotion
• Health promotion is "the process of enabling
people to increase control over, and to improve
health “
• It is not directed against any particular disease,
but is intended to strengthen the host through a
variety of approaches (interventions)
– health education
– environmental modifications
– nutritional interventions
– lifestyle and behavioural changes

Specific protection
• To avoid disease altogether is the ideal but this is
possible only in a limited number of cases.
– immunization
– use of specific nutrients
– chemoprophylaxis
– protection against occupational hazards
– protection against accidents
– protection from carcinogens
– avoidance of allergens
– the control of specific hazards in the general environment,
e.g., air pollution, noise control
• control of consumer product quality and safety of foods, drugs,
cosmetics, etc.

Early diagnosis and treatment
• A WHO Expert Committee defined early
detection of health impairment as '·the detection
of disturbances of homoeostatic and
compensatory mechanism while biochemical,
morphological, and functional changes are still
reversible. " Thus, in order to prevent overt
disease or disablement, the criteria of diagnosis
should, if possible, be based on early
biochemical, morphological and functional
changes that precede the occurrence of manifest
signs and symptoms. This is of particular
importance in chronic diseases.

• The earlier a disease is diagnosed and treated
the better it is from the point of view of
prognosis and preventing the occurrence of
further cases (secondary cases) or any long-
term disability

Disability limitation
• When a patient reports late in the
pathogenesis phase, the mode of intervention
is disability limitation. The objective of this
intervention is to prevent or halt the transition
of the disease process from impairment to
handicap.
• Concept of disability

• Impairment : An impairment is defined as "any
loss or abnormality of psychological, physiological
or anatomical structure or function". e .g., loss of
foot, defective vision or mental retardation. An
impairment may be visible or invisible, temporary
or permanent, progressive or regressive. Further,
one impairment may lead to the development of
"secondary" impairments as in the case of
leprosy where damage to nerves (primary
impairment) may lead to plantar ulcers
(secondary impairment).

• Disability : Because of an impairment, the
affected person may be unable to carry out
certain activities considered normal for his
age, sex, etc. This inability to carry out certain
activities is termed "disability". A disability has
been defined as ''any restriction or lack of
ability to perform an activity in the manner or
within the range considered normal for a
human being".

• Handicap : As a result of disability, the person
experiences certain disadvantages in life and is
not able to discharge the obligations required of
him and play the role expected of him in the
society. This is termed "handicap~, and is defined
as "a disadvantage for a given individual, resulting
from an impairment or a disability, that limits or
prevents the fulfilment of a role that is normal
(depending on age, sex, and social and cultural
factors) for that individual" .

• Rehabilitation: Rehabilitation has been defined as "the
combined and coordinated use of medical, social,
educational and vocational measures for training and
retraining the individual to the highest possible level of
functional ability“. It includes all measures aimed at
reducing the impact of disabling and handicapping
conditions and at enabling the disabled and
handicapped to achieve social integration. Social
integration has been defined as the active participation
of disabled and handicapped people in the mainstream
of community life

INDICATORS OF HEALTH
• A question that is often raised is: How healthy is a
given community ? Indicators are required not
only to measure the health status of a
community, but also to compare the health status
of one country with that of another; for
assessment of health care needs; for allocation of
scarce resources; and for monitoring and
evaluation of health services, activities, and
programmes. Indicators help to measure the
extent to which the objectives and targets of a
programme are being attained.

Characteristics of indicators
• Indicators have been given scientific respectability; for
example ideal indicators
– should be valid, i.e., they should actually measure what
they are supposed to measure;
– should be reliable and objective, i.e., the answers should
be the same if measured by different people in similar
circumstances;
– should be sensitive, i.e., they should be sensitive to
changes in the situation concerned,
– should be specific, i.e., they should reflect changes only in
the situation concerned,
– should be feasible, i.e., they should have the ability to
obtain data needed, and;
– should be relevant, i.e., they should contribute to the
understanding of the phenomenon of interest.

• Mortality indicators
• Morbidity indicators
• Disability rates
• Nutritional status indicators
• Health care delivery indicators
• Utilization rates
• Indicators of social and mental health
• Environmental indicators
• Socio-economic indicators
• Health policy indicators
• Indicators of quality of life, and
• Other indicators.

Mortality indicators
• Crude death rate
• Life expectancy at birth
• Age-specific death rates
• Infant mortality rate
• Child death rate
• Maternal (puerperal) mortality rate
• Disease-specific mortality rate
• Case fatality rate ……

Morbidity indicators
• incidence and prevalence
• notification rates
• attendance rates at out-patient departments,
health centres, etc.
• admission, readmission and discharge rates
• duration of stay in hospital, and
• spells of sickness or absence from work or
school.

Disability indicators
• Event-type indicators
– Number of days of restricted activity
– Bed disability days
– Work-loss days (or school-loss days) within a specified
period
• Person - type indicators
– Limitation of mobility: For example, confined to bed,
confined to the house, special aid in getting around either
inside or outside the house.
– Limitation of activity: For example, limitation to perform
the basic activities of daily living (ADL)- e.g., eating,
washing, dressing, going to toilet. moving about, etc;
limitation in major activity, e.g., ability to work at a job,
ability to housework, etc.

Nutritional status indicators
• anthropometric children, e.g., circumference;
measurements of weight and height.
preschool mid-arm
• heights (and sometimes weights) of children
at school entry; and
• prevalence of low birth weight (less than 2.5
kg).

Health care delivery indicators
• Doctor- population ratio
• Doctor-nurse ratio
• Population-bed ratio
• Population per health/subcentre, and
• Population per trained birth attendant.

Utilization rates
• proportion of infants who are "fully immunized‘”
• proportion of pregnant women who receive
antenatal care, or have their deliveries supervised
by a trained birth attendant.
• percentage of the population using the various
methods of family planning.
• bed-occupancy rate (i.e., average daily in-patient
census/average number of beds).
• average length of stay (i.e., days of care
rendered/ discharges), and
• bed turnover ratio (i.e., discharges/average beds).

Indicators of social and mental health
• As long as valid positive indicators of social
and mental health are scarce, it is necessary to
use indirect measures, viz. indicators of social
and mental pathology. These include suicide,
homicide, other acts of violence and other
crime; road traffic accidents, juvenile
delinquency: alcohol and drug abuse;
smoking; consumption of tranquillizers;
obesity, etc

Environmental indicators
• Environmental indicators reflect the quality of
physical and biological environment in which
diseases occur and in which the people live.
They include indicators relating to pollution of
air and water, radiation, solid wastes, noise,
exposure to toxic substances in food or drink.
Among these, the most useful indicators are
those measuring the proportion of population
having access to safe water and sanitation
facilities.

Socio-economic indicators
• rate of population increase
• per capita GNP
• level of unemployment
• dependency ratio
• literacy rates, especially female literacy rates
• family size
• housing: the number of persons per room, and
• per capita "calorie" availability.

Health policy indicators
• proportion of GNP spent on health services
• proportion of GNP spent on healthrelated
activities (including water supply and
sanitation, housing and nutrition, community
development), and
• proportion of total health resources devoted
to primary health care.

Indicators of quality of life
• physical quality of life index

Levels of prevention
• Primodial
• Primary
• Secondary
• Tertiary