Public health

CONCEPTS OF HEALTH AND DISEASE
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Department of Public Health Dentistry
PRESENTED BY-
Dr. SWATI (PG 2nd year)

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CONTENTS
INTRODUCTION
DEFINITION OF HEALTH
CHANGING ONCEPTS OF HEALTH
NEW PHILOSOPHY OF HEALTH
DIMENSIONS OF HEALTH
CONCEPT OF WELLBEING
SPECTRUM OF HEALTH
DETERMINANTS OF HEALTH
INDICATORS OF HEALTH
CONCEPT OF CAUSATION
NATURAL HISTORY OF DISEASE.

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DISEASE CLASSIFICATION
CHANGING PATTERN OF DISEASE
CONCEPTS OF CONTROL
CONCEPTS OF PREVENTION
CONCLUSION
REFERENCES

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• Health is a common concern in most communities.
• In fact, all communities have their concepts of
health, as part of their customs and traditions.
• Health continues to be a neglected issue despite
hypocrisy.
• Health is often taken for granted, and its importance
is not fully understood until it is lost.
• However, during the last few decades there has
been a revival that health is a fundamental right and
a world-wide social goal and
• It is essential to the satisfaction of basic human
needs and to an improved quality of life
INTRODUCTION

DEFINITION OF HEALTH
“Health is a state of complete physical, mental and
social well being and not merely an absence of disease
or infirmity”
- “and the ability to lead a socially and economically
productive life.”
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CHANGING CONCEPTS
BIOMEDICAL CONCEPT
ECOLOGICAL CONCEPT
PSYCHOSOCIAL CONCEPT
HOLISTIC CONCEPT
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BIOMEDICAL CONCEPT
• Health has been viewed as an “absence of disease” and if
one was free from disease, then the person was considered
healthy. This is known as the biomedical concept.
• This concept has the basis in the "germ theory of disease"
which dominated medical thought at the turn of the 20th
century.
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• The biomedical model, for all its spectacular success
in treating disease, was found inadequate to solve
some of the major health problems of mankind (e.g.,
malnutrition , chronic diseases, accidents, drug abuse,
mental illness, environmental pollution. population
explosion) by elaborating the medical technologies
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ECOLOGICAL CONCEPT
• Deficiencies in the biomedical concept gave rise to other
concepts.
• The ecologists put forward a hypothesis, which viewed
health as a dynamic equilibrium between man and his
environment, and disease a maladjustment of the human
organism to environment.
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• The ecological concept raises two issues, viz.
imperfect man and imperfect environment. History
argues strongly that improvement in human
adaptation to natural environments can lead to longer
life expectancies and a better quality of life - even in
the absence of modern health delivery services.
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PSYCHOSOCIAL CONCEPT
• According to this, health is influenced by social,
psychological, cultural, economic and political
factors.
• Thus, health is both a biological and social
phenomenon.
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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.
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• 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.
• The emphasis is on the promotion and protection of
health.
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NEW PHILOSOPHY OF HEALTH
• 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.
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Dimensions of HealthPhysical
Mental Social
Spiritual
Emotional
Cultural
Nutritional
Preventive
Socioeconomic Philosophical
Educational
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Physical Dimension
• The physical dimension of health is probably the
easiest to understand.
• 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. However,
the term "optimum" is not definable.
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Evaluation Of Physical Health
They include :
• self assessment of overall health
• inquiry into symptoms of ill-health and risk factors
• inquiry into medications
• restricted activity within a specified time, degree of fitness)
• inquiry into use of medical services (e.g., the number of
visits to a physician, number of hospitalizations) in the
recent past
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• standardized questionnaires for cardiovascular
diseases
• standardized questionnaires for respiratory diseases
clinical examination
• nutrition and dietary assessment, and biochemical
and laboratory investigations.
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Mental Dimension
• Good mental health is the ability to respond to the
many varied experiences of life with flexibility and a
sense of purpose.
• 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"
• .
19

• It is also the ability to manage thoughts and deal with
the challenges that you meet in life.
• Some signs of good mental health are being realistic
about strengths and weaknesses, being open minded,
and responsible
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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.
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• 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.
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Social Dimension
• It has been defined as “quantity and quality of an
individual’s interpersonal ties and the extent of
involvement with the community”.
• 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.
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Spiritual Dimension
• Spiritual health in this context, refers to that part of
the individual which reaches out and strives for
meaning and purpose in life..
• 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.
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Emotional Dimension
• 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".
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• Experts in psychobiology have been relatively
successful in isolating these two separate dimensions.
• With this new data, the mental and emotional aspects
o humanness may have to be viewed as two separate
dimensions of human health.
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Vocational Dimension
• The vocational aspect of life is a new dimension.
• It is part of human existence. When work is fully
adapted to human goals, capacities and limitations,
work often plays a role in promoting both physical and
mental health.
• Physical work is usually associated with an
improvement in physical capacity, while goal
achievement and self-realization in work are a source of
satisfaction and enhanced self-esteem
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A few other dimensions include:
 Philosophical
 Cultural
 Socio-economic
 Environmental
 Educational
 Nutritional
 Curative
 Preventive
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POSITIVE HEALTH
“Perfect functioning” of body and mind.
• 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; Psychologically as a state in which the
individual feels a sense of perfect well being and a
mastery over his environment, and Socially, as a state
in which the individual’s capacities for participation in
the social system are optimal.
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CONCEPT OF WELL BEING
OBJECTIVE SUBJECTIVE
-STANDARD OF LIVING
-LEVEL OF LIVING
QUALITY OF LIFE
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Psychologists have pointed out that the "well-being" of an individual or group of individuals
have objective and subjective components.
The objective components relate to such concerns as are generally known by the term
"standard of living" or '·level of living·•.
The subjective component of wellbeing (as expressed by each individual) is referred to as
"quality of life"

CONCEPT OF WELL BEING
• The Standard of Living refers to the usual scale of our
expenditure, the goods we consume, and the services we
enjoy”.
• It includes the level of education, employment status,
food, dress, house, amusements, and comforts of
modern living.
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THE LEVEL OF LIVING
• The Level of Living is parallel term for standard of
living in United Nations.
• It consists of nine components: health, food
consumption, education, occupation and working
conditions, housing, social security, clothing,
recreation and leisure and human rights.
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QUALITY OF LIFE
• WHO defined Quality of life" as the product of the
interplay between social, health, economic, and
environmental conditions which affect human and
social development.
• It is a broad-ranging concept, incorporating a person's
physical health, psychological state, level of
independence, social relationships, personal belief and
relationship to salient features in the environment"
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• The quality of life is measured using either of the
following:
• PQLI (Physical Quality of Life index)
• HDI (Human Development Index) and
• Human poverty index (HPI)
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PQLI (Physical Quality of Life index)
• The "Physical quality of life index" is one such index.
• It consolidates three indicators, viz. infant mortality,
life expectancy at age one, and literacy.
• These three components measure the results rather
than inputs. As such they lend themselves to
international and national comparison.
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Human Development Index (HDI)
• Human development index (HDI) is defined as "a
composite index focusing on three basic dimensions
of human development : to lead a long and healthy
life measured by life expectancy at birth; the ability to
acquire knowledge, measured by mean years of
schooling and expected years of schooling; and the
ability to achieve a decent standard of living,
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SPECTRUM OF HEALTH
Positive Health
Better Health
Freedom from sickness
Unrecognized Sickness
Mild Sickness
Severe Sickness
Death
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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.
Health sickness spectrum

DETERMINANTS OF HEALTH
• Biological
• Behavioral and Socio-
cultural
• Environment
• Socio-economic
• Health Services
• Ageing of the
population
• Gender
• Other Factors 38

BIOLOGICAL
• From the genetic stand-point. Health may be defined as
that "state of the individual which is based upon the
absence from the genetic constitution of such genes as
correspond to characters that take the form of serious
defect and derangement and to the absence of any
aberration in respect of the total amount of chromosome
material in the karyotype or stated in positive terms, from
the presence in the genetic constitution of the genes that
correspond to the normal characterization and to the
presence of a normal karyotype"
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BEHAVIOURALAND SOCIO-CULTURAL
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It is composed of cultural and behavioural patterns and
lifelong personal habits (e.g., smoking, alcoholism) that have
developed through processes of socialization.
Lifestyles are learnt through social interaction with parents,
peer groups, friends and siblings and through school and
mass media..
It may be noted that not all lifestyle factors are harmful.
There are many that can actually promote health. These
include adequate nutrition, enough sleep, physical exercise
etc.

ENVIRONMENT
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Environment is classified as "internal" and "external''.
The internal environment of man pertains to "each and
every component part, every tissue, organ and organ
system and their harmonious functioning within the
system". Internal environment is the domain of internal
medicine.
The external or macro-environment consists of those
things to which man is exposed after conception. It is
defined as ·'all that which is external to the individual
human host"

SOCIOECONOMIC FACTORS
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Socio-economic conditions have long been known to
influence human health. For the majority of the world's
people, health status is determined primarily by their
level of socio-economic development, e.g., per capita
GNP, education, nutrition, employment, housing, the
political system of the country, etc. Those of major
importance are

• Economic conditions: The per capita GNP is the
most widely accepted measure of general economic
performance.
• There can be no doubt that in many developing
countries, it is the economic progress that has been
the major factor in reducing morbidity. increasing
life expectancy and improving the quality of life.
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• The economic status determines the purchasing power,
standard of living, quality of life, family size and the
pattern of disease and deviant behaviour in the
community.
• It is also an important factor in seeking health care.
• Ironically, affluence may also be a contributory cause
of illness as exemplified by the high rates of coronary
heart disease, diabetes and obesity in the uppersocio-
economic groups.
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Education: A second major factor influencing health
status is education (especially female education).
• The world map of illiteracy closely coincides with the
maps of poverty, malnutrition, ill health, high infant
and child mortality rates.
• Studies indicate that education, to some extent,
compensates the effects of poverty on health,
irrespective of the availability of health facilities.
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Occupation
The very state of being employed in productive work
promotes health , because the unemployed usually show a
higher incidence of ill health and death.
For many, loss of work may mean loss of income and status.
It can cause psychological and social damage.
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Political system
• Health is also related to the country's political system.
• Often the main obstacles to the implementation of health
techno1ogies are not technical, but rather political.
• Decisions concerning resource allocation, manpower
policy, choice of technology and the degree to which
health services are made available and accessible to
different segments of the society are examples of the
manner in which the political system can shape
community health services
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HEALTH SERVICES
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The term health and family welfare services cover a wide
spectrum of personal and community services for treatment
of disease, prevention of illness and promotion of health.
The purpose of health services is to improve the health status
of the population. For example, immunization of children can
influence the incidence/prevalence of particular diseases.
Provision of safe water can prevent mortality and morbidity
from water-borne diseases.
The care of pregnant women and children would contribute
to the reduction of maternal and child morbidity and
mortality.

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Ageing of the population
• By the year 2020, the world will have more than 1.4
billion people aged 60 and over, and more than two-
thirds of them living in developing countries.
• Although the elderly in many countries enjoy better
health than hitherto, a major concern of rapid
population ageing is the increased prevalence of
chronic diseases and disabilities, both being conditions
that tend to accompany the ageing process and
deserve special attention.
.

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Gender
• The 1990s have witnessed an increased concentration
on women's issues.
• In 1993, the Global Commission on Women's Health
was established.
• The commission drew up an agenda for action on
women's health covering nutrition, reproductive
health, the health consequences of violence, ageing,
lifestyle related conditions and the occupational
environment.
• It has brought about an increased awareness among
policy- makers of women health issues and encourages
their inclusion in all development plans as a priority

OTHERS
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• Other contributions to the health of population derive
from systems outside the formal health care system,
i.e., health related systems (e.g. , food and agriculture,
education, industry, social welfare, rural development),
as well as adoption of policies in the economic and
social fields that would assist in raising the standard of
living.
• This would include employment opportunities,
increased wages, prepaid medical programmes and
family support systems.

• 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.
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Characteristics Of Indicators
• It 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.
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• MORTALITY RATE
• MORBIDITY RATE
• DISABILITY RATE
• NUTRITIONAL STATUS
• HEALTH CARE DELIVARY
INDICATORS
• ENVIRONMENTAL
• SOCIOECONOMIC
• HEALTH POLICY
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1. Mortality indicators:
• - Crude death rate- It is defined as the number of deaths
per 1000 population per year in a given community. It
indicates the rate at which people are dying. Strictly
speaking, health should not be measured by the number of
deaths that occur in a community.
• - infant mortality rate- Infant mortality rate is the ratio of
deaths under 1 year of age in a given year to the total
number of live births in the same year; usually expressed as
a rate per 1000 live births.
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• child mortality rate- It is defined as the number of
deaths at ages 1-4 years in a given year, per 1000
children in that age group at the mid-point of the year
concerned. It thus excludes infant mortality.
• maternal mortality rate- Maternal (puerperal)
mortality accounts for the greatest proportion of deaths
among women of reproductive age in most of the
developing world. There are enormous variations in
maternal mortality rate according to country's level of
socioeconomic status.
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• Case fatality rate : Case fatality rate measures the risk
of persons dying from a certain disease within a given
time period.
• Case fatality rate is calculated as number of deaths
from a specific disease during a specific time period
divided by number of cases of the disease during the
same time period, usually expressed as per 100.
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• 2. Morbidity indicators- morbidity indicators are used
to supplement mortality data to describe the health status
of a population.
• Morbidity statistics have also their own drawback; they
tend to overlook a large number of conditions which are
subclinical or inapparent, that is, the hidden part of the
iceberg of disease.
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The following morbidity rates are used for assessing ill-
health in the community
a. incidence and prevalence
b. notification rates
c. attendance rates at out-patient departments, health
centres, etc.
d. admission, readmission and discharge rates
e. duration of stay in hospital, and
f. spells of sickness or absence from work or school.
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. Disability rates
• The disability rates are based on the premise or notion
that health implies a full range of daily activities.
• The commonly used disability rates fall into two groups:
(a) Event-type indicators and (b) person-type indicators
Event-type indicators
• i) Number of days of restricted activity
• ii) Bed disability days
• iii) Work-loss days (or school-loss days) within a
specified period
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Person - type indicators
i) Limitation of mobility: For example, confined to bed,
confined to the house, special aid in getting around
either inside or outside the house.
ii) 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.
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4. Nutritional status indicators:
• Three nutritional status indicators are considered
important as indicators of health status. They are :
a. anthropometric children, e.g., circumference;
measurements of weight and height.
b. heights (and sometimes weights) of children at
school entry; and
c. prevalence of low birth weight (less than 2.5 kg).
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Health care delivery indicators
The frequently used indicators of health care delivery are:
a. Doctor- population ratio
b. Doctor-nurse ratio
c. Population-bed ratio
d. Population per health/subcentre, and
e. Population per trained birth attendant.
• These indicators reflect the equity of distribution of
health resources in different parts of the country, and of
the provision of health care.
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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
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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.
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• Rate of population increase
• Per capita GNP
• Level of unemployment
• Dependency ratio
• Literacy rates
• Family size
• Housing
• Per capita calorie availability
7/12/2020 Seminar by Eby 66
Socio-economic indicators

• Proportion of GNP spent on health services
• Proportion of GNP spent on health related activities.
• Proportion of total health resources devoted to
primary health care
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Health policy indicators

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CONCEPT OF CAUSATION
NATURAL HISTORY OF DISEASE.
DISEASE CLASSIFICATION
CHANGING PATTERN OF DISEASE
CONCEPTS OF CONTROL
CONCEPT OF DISEASE

Definition
• Webster defines disease as “a condition in which
body health is impaired, a departure from a state of
health, an alteration of human body interrupting
the performance of vital functions.”
• From an ecological point of view, disease is defined as
“a maladjustment of the human organism to the
environment”
• From a sociological point of view, disease is
considered a social phenomenon, occurring in all
societies and defined and fought in terms of the
particular cultural forces prevalent in the society 69

• Disease has many shades ranging from inapparent
(subclinical) cases to severe manifest illness.
• Some disease commence acutely (eg. food
poisoning) and some insidiously (mental illness,
rheumatoid arthritis)
• In some diseases, a carrier state occurs in which
individual remains outwardly healthy but has the
potential to infect others
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• In some cases, the same disease may be caused by
multiple organisms (diarrhoea)
• Some diseases have a short range and some have a
long course.
• in some diseases it is difficult to differentiate
between normal and sub normal due to lack of
symptoms present (hypertension)
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• Disease: is a physiological/psychological dysfunction
• Illness: is a subjective state of a person who feels aware
of not being well
• Sickness: is a state of social dysfunction i.e. a role that
the individual assumes when ill
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Concept of Causation
• Germ theory of disease
• Epidemiological triad
• Multifactorial causation
• Web of causation
73

GERM THEORY OF DISEASE
• According to this concept, disease is seen as one-to-
one relationship between causal agent and disease.
• Disease agent man disease
• However it is now recognized that a disease is caused
by a number of factors, rather than single agent alone.
74

EPIDEMIOLOGICAL TRIAD
• The concept of multifactorial reasons for the
development and progress of the disease led to
development of this model.
75

• The disease “agent” is defined as a substance, living or
non living or a force, the excessive presence or relative
lack of which might perpetuate a disease process.
• AGENT FACTORS
1. biological agents: bacteria, virus, fungi
2. nutrient agents: proteins, fat, carbohydrates, minerals,
water
3. physical agents: excessive heat, cold, pressure,
radiation, electricity, sound etc.
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4. Chemical agents:
• endogenous:- produced inside the body i.e. urea,
Calcium carbonate, ketones etc.
• exogenous:- allergens, metals, fumes, dust, gases
etc.
5. Mechanical agents: exposure to chronic friction
and mechanical forces may result in tearing, sprains,
dislocation or even death.
77

• 6. Absence or insufficiency or excess of a factor
necessary for health: eg. hormones
• 7. Social agents: poverty, smoking, drugs, alcohol,
unhealthy lifestyles etc.
78

HOST FACTORS
• 1. Demographic characters: age, gender,
ethnicity
• 2. Biological characters: genetic factors
• 3. Social and economic characters: education,
socio-economic status, occupation, stress, marital
status
• 4. life style factors: living habits, personality
traits, alcohol, exercise etc. 79

ENVIRONMENTAL FACTORS
1. Physical environment:
non living things and physical factors like soil, air,
water, housing, climate, geography, heat, light, noise,
radiation etc.
2. Biological environment:
all the living things
3. Psychosocial environment
• social, economic and cultural contexts.
80

Multifactorial causation
• Pettenkofer of Munich (1819-1901) was an early
proponent of this concept.
• The purpose of knowing the, multiple factors of disease
is to quantify and arrange them in priority sequence
(prioritization) for modification or amelioration to
prevent or control disease.
• The multifactorial concept offers multiple approaches for
the prevention/control of disease.
81

WEB OF CAUSATION OF DISEASE
• Suggested by MacMahon and Pugh
• Ideally suited in the study of chronic disease, where
the disease agent is often not known but is the outcome of
interaction of multiple factors.
• The "web of causation" considers all the predisposing
factors of any type and their complex inter-
relationshionship with each other.
82

• It does not imply that the disease cannot be
controlled unless all the multiple causes or chains of
causation or at least a number of them are
appropriately controlled or removed.
• Sometimes removal or elimination of just only one
link or chain may be sufficient to control disease,
provided that link is sufficiently important in the
pathogenic process.
• It is a multi-factorial event but all factors do not bear
the equal weightage.
83

Natural History of disease
• It signifies the way in which a disease evolves over
time from the earliest stage of its pre pathogenesis
phase to its termination as recovery, disability or
death, in the absence of treatment or prevention.
• The epidemiologist, by studying the natural history of
disease in the community setting is in a unique
position to fill the gaps in knowledge about the
natural history of disease.
85

• It is customary to describe the natural history of
disease as consisting of two phases: prepathogenesis
(i.e. , the process in the environment) and
pathogenesis (i.e., the process in man).
86

Pre pathogenesis phase
• In this phase the disease agent has not yet entered
man, but the factors which favour its interaction with
the human host already exist in the environment.
• An interaction of Agent, Host and Environment are
required to initiate the disease process.
87

• The agent, host and environment operating in
combination determine not only the onset of disease
which may range from a single case to epidemics but
also the distribution of disease in the community.
88

Pathogenesis phase
• The pathogenesis phase begins with the entry of the
disease "agent" in the susceptible human host.
• The disease agent multiplies and induces tissue and
physiological changes, the disease progresses through
a period of incubation and later through early and late
pathogenesis.
89

• The final outcome of the disease may be recovery,
disability or death. The pathogenesis phase may be -
modified by intervention measures such as
immunization and chemotherapy.
• It is useful to remember at this stage that the host's
reaction to infection with a disease agent is not
predictable. That is, the infection may be clinical or
subclinical; typical or atypical or the host may become
a carrier with or without having developed clinical
disease
90

Agent factors
• The disease "agent" is defined as a substance, living
or non-living, or a force, tangible or intangible the
excessive presence or relative lack -of which may
initiate or perpetuate a disease process.
• A disease may have a single agent, a number of
independent alternative agents or a complex of two or
more factors whose combined presence is essential
for the development of the disease.
91

• Disease agents may be Biological, Nutrient, Physical,
Chemical, Exogenous (arising outside of human
host), Mechanical, Absence or insufficiency or excess
of a factor necessary to health and Social.
92

Host factors (intrinsic)
• Demographic characteristics such as age, sex,
ethnicity;
• Biological characteristics such as genetic factors,
biochemical levels of the blood, immunological
factors; and physiological function of different organ
systems of the body,
93

• Social and economic characteristics such as
socioeconomic status, education, occupation, stress,
marital status, housing, etc. and
• Lifestyle factors such as personality traits, ,nutrition,
physical exercise, habits, behavioural patterns, etc.
94

Environmental factors (extrinsic)
• Environmental factors have a vital role in health and
disease.
• The external or macro- environment is defined as "all
that which is external to the individual human host,
living and non-living and with which he is in constant
interaction-this includes all of man's external
surroundings such as air, water, food, housing, etc.
95

• The environment of man has been divided into three
components-
• physical,
• biological and
• psychosocial.
96

Physical environment
• "Physical environment” is refers to non-living things
and physical factors (e.g., air, water, soil, housing,
climate, geography, heat, light, noise, debris,
radiation, etc) with which man is in constant
interaction.
• Man is living today in a highly complicated
environment which is getting more complicated as
man is becoming more ingenious.
97

Biological environment
• The biological environment consists of living things
such as viruses and other microbial agents, insects,
rodents, animals and plants which surround man in a
harmonious inter-relationship.
• When for any reason, this harmonious relationship is
disturbed, ill health results in the area of biological
environment
98

Psychosocial environment
• It includes a complex of psychosocial factors which are
defined as "those factors affecting personal health, health
care and community well -being that stem from the
psychosocial make-up of individuals and the structure and
functions of social groups”.
• They include cultural values, customs, habits, beliefs,
attitudes, morals, religion, education, lifestyle, community
life, health services, social and political organization.
• The law of the land, customs, attitudes, beliefs, traditions
regulates the interactions among groups of individuals and
families. 99

Risk factors
• The term "risk factor" may be an attribute or exposure
that is significantly associated with development of
disease or a determinant that can be modified by
intervention, thereby reducing the possibility of
occurrence of disease or other specified outcomes.
• Risk factors are often suggestive, but absolute proof of
cause and effect between a risk factor and disease is
usually lacking.
100

• Combination of risk factors in the same individual
may be purely additive or synergistic.
• Risk factors may be causative as in smoking for lung
cancer) or they may be merely contributory to the
undesired outcome such as lack of physical exercise
is a risk factor for coronary heart disease).
101

• Some risk factors can be modified; others cannot be
modified.
• The modifiable factors amenable to intervention include
smoking, hypertension, elevated serum cholesterol,
physical activity, obesity, etc.
• The unmodifiable or immutable risk factors such as
age, sex, race, family history and genetic factors are not
subject to change.
• They act more as signals in alerting health professionals
and other personnel to the possible outcome.
102

• Epidemiological methods are needed to identify risk
factors and estimate the degree of risk.
• The detection of risk factors should be considered a
before prevention or intervention.
103

SPECTRUM OF DISEASE
• The term "spectrum of disease" refers to variations in
the manifestations of disease with sub clinical
infections at one end, illnesses ranging in severity
from mild to severe in the middle and at the other end
are fatal illnesses.
• In infectious diseases, the spectrum of disease is also
referred to as the "gradient of infection".
104

• The sequence of events in the spectrum of disease can
be interrupted by early diagnosis and treatment or by
preventive measures which if introduced at a
particular point will prevent or retard the further
development of the disease.
105

ICEBERG PHENOMENON OF DISEASE
• It has been seen that the pattern of disease in hospitals is
quite different from that in the community.
• That is, a large proportion of disease is hidden from view
in the community that is evident to the physician in the
hospital.
• This analogy is termed as, ‘Iceberg Phenomenon of
Disease’.
106

107
The floating tip is the portion which the physician
sees in practice.
Submerged portion
represents the hidden mass of
disease (subclinical cases, Pre-
symptomatic, undiagnosed cases,
etc).
Being a fact as large amount is in the hidden part, its detection and
control is a challenge and must doer in preventive aspect.
What the physician
sees
What the physician
does not see
Demarcation between apparent and
inapparent disease

CONCEPTS OF CONTROL
• Disease control
• Disease elimination
• Disease eradication
• Monitoring and surveillance
• Sentinel surveillance
• Evaluation of control
108

Disease control
• The term "disease control" describes ongoing
operations aimed at reducing the incidence of disease,
the duration of disease, and consequently the risk
of transmission, the effects of infection, including
both the physical and psychosocial complications and
the financial burden to the community.
• In disease control, the disease "agent" is permitted to
persist in the community at a level where it ceases to
be a public health problem according to the tolerance
of the local population.
109

DISEASE ELIMINATION
• The term "elimination" is used to describe interruption
of transmission of disease, as for example, elimination
of measles, polio and diphtheria from large geographic
regions or areas.
110

DISEASE ERADICATION
• Eradication of disease implies termination of all
transmission of infection by examination of the
infectious agent.
• As on now, smallpox is the only disease that has been
eradicated.
111

Monitoring and surveillance
• Monitoring is "the performance and analysis of
routine measurements aimed at detecting changes in
the environment or health status of population", such as
monitoring air pollution, water quality, growth and
nutritional status, etc.
• Surveillance is defined as "the continuous scrutiny of
the factors that determine the occurrence and
distribution of disease and other conditions of ill-
health", such as epidemiological surveillance ,
demographic surveillance, nutritional surveillance , etc.
112

• Surveillance provide information about new and
changing trends in the health status of a population,
feed -back which may be expected to modify the policy
and the system itself and lead to redefinition of
objectives, and timely warning of public health -
disasters so that interventions can be mobilized.
113

Sentinel Surveillance
• Sentinel surveillance is a method for identifying the
missing cases and thereby supplementing due notified
cases.
• The sentinel data is extrapolated to the entire
population to estimate the disease prevalence in the
total population.
114

Evaluation of control
• Evaluation is the process by which results are
compared with the intended objectives, or more simply
the assessment of how well a programme is
performing.
• Evaluation may be crucial in identifying the health
benefits derived (impact on morbidity, mortality,
sequelae, patient satisfaction).
• Evaluation can be useful in identifying performance
difficulties.
115

CONCEPTS OF PREVENTION
Successful prevention depends upon a knowledge of
• causation,
• dynamics of transmission,
• identification of risk factors and risk groups,
• availability of prophylactic or early detection and treatment
measures;
• an organization -for applying these measures to appropriate
persons or groups, and
• continuous evaluation of and development of procedures
applied.
• The objective is to intercept or oppose the "cause" and
thereby the disease process
116

Levels of prevention
• Primordial prevention
• Primary prevention
• Secondary prevention
• Tertiary prevention
117

Primordial prevention
• Primordial prevention is prevention of emergence or
development of risk factors in countries or population
groups in which they have not yet appeared.
• In primordial prevention, efforts are directed towards
discouraging children from adopting harmful
lifestyles.
• The main intervention in primordial prevention is
through individual and mass education.
118

Primary prevention
• Primary prevention is a desirable goal relies on
holistic approach that signifies intervention in the pre
pathogenesis phase of a disease or health problem or
other departure from health.
• It can be defined as "action taken prior to the onset of
disease, which removes the possibility that a disease
will ever occur".
119

• Primary prevention may be accomplished by
measures designed to promote general health and
well-being, and quality of life of people or by specific
protective measures.
• It concerns an individual's attitude towards life and
health and the initiative he takes about positive and
responsible measures for himself, his family and his
community.
120

• For the primary prevention of chronic diseases where
the risk factors are established The WHO has
recommended :
• the population (mass) strategy
• high-risk strategy approach
121

• The population (mass) strategy- Population strategy
is directed at the whole population irrespective of
individual risk levels and is aimed at towards socio-
economic, behavioral and lifestyle changes.
• High-risk strategy approach- The high-risk strategy
aims to bring preventive care to individuals at special
risk. This requires detection of individuals at high risk
by the optimum use of clinical methods.
122

SECONDARY PREVENTION
• Secondary prevention can be defined as "action which
halts the progress of a disease at its incipient stage and
prevents complications"'.
• The specific Interventions are early diagnosis and
adequate treatment.
• The health programmes initiated by governments are
usually at the level of secondary prevention.
123

• The drawback of secondary prevention is that the
patient has already been subject to mental anguish,
physical pain and the community to loss of
productivity.
• These situations are not encountered in primary
prevention
124

TERTIARY PREVENTION
• Tertiary prevention can be defined as “all measures
available to reduce or limit impairments and
disabilities, minimize suffering caused by
existing departure from good health and to promote
the patient's adjustment to irremediable conditions”.
• The specific modes of Interventions are disability
limitation and rehabilitation
125

CONCLUSION
• A fundamental issue of great importance to all health
professionals is the need to identify and tackle the
causes of disease in society.
• The promotion of health and a reduction in health
inequalities requires effective action on the
determinants of health.
126

127
• Park K. Park’s textbook of Preventive and Social Medicine. 25th edition , Madhya
Pradesh: Banarsidas Bhanot Publishers.
• Daly B, Watt R, Batchelor P, Treasure E. Essential Dental Public Health. New Delhi:
Oxford University Press.
• Peter S. Essentials of public health dentistry. 6th edition, New Delhi: Arya Medi
Publishing House.
• Josheph John- Textbook of Community and preventive Dentistry- 3rd Edition
• Marya CM. A textbook of Public Health Dentistry. First ed. Jaypee publishers,
2011.
REFERENCES

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