Health and disease


☆A)CONCEPT OF HEALTH  

Health is a common theme in most cultures. In fact, all communities have their concepts of health, as part of their culture. Among definition still used, probably the oldest is that health is the " absence of disease". In some cultures, health and harmony are considered equivalent, harmony  being defined as " being at peace with the self, the community, god and cosmos". The ancient Indians and Greeks shared this concept and attributed disease to disturbances in bodily equilibrium of what they called " humors". 

Definition of  health 

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". 

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. Although these dimensions function and interact with one another,each has its own nature, and for descriptive purposes will be treated separately. 


1): 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.

  
  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 ft, 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 Ibs ( 2.3 kg ) more or less than the individual's  weight at the age of 25 years. This state of normality has fairly  wide limits. These limits are set by observation of a large number of " normal " people, who are free from evident disease.

Evoluation of physical health:

   Modern medicine has evolved tools and techniques which may be used in various  combinations for the assessment  of physical  health. They include :

  
☆ self assessment  of overall health 

☆ Inquire  into symptoms of ill_ health and risk factors.

☆ Inquire  into medications

☆ Inquire  into levels of activity (e.g., number of days of restricted  activity within a specified time, degree of  fitness)

☆ inquire  into use  of medical services (e.g., the number of visits to a physician, number of hospitalizations) in the recent past

☆ Standardized questionnaires for cardiovascular diseases 

☆ Standardized questionnaires  for respiratory disease 

☆Clinical examination 

☆ nutrition  and dietary assessment,  and 

☆ Nutrition and dietary assessment,  and 


☆ Biochemical and laboratory  investigations. 

  At the community level, the state of health may be assessed by such indicators as.death rate, infant mortality rate and expectation of life. Ideally, each piece of information  should be individually useful and when combined should permit a more complete health  profile of individuals  and communities. 

2. 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 th individual  and the surrounding world, a state of harmony  between  oneself and others,  a co__ existence between  the realities of the self  and that of other people and that of the environment ". 

      Psychologists have mentioned  the following  characteristics as attributes of a mentally  healthy  person 


a):   A mentally  healthy  person is free from internal conflicts; he is not at " war " with himself. 


b):  He is well _ adjusted,  i.e., he is able to get along well with others. He accepts criticism  and is not easily upset.

c) : He searches  for identity. 

d): He has a strong sense of self _ esteem.

e): He knows himself  : his needs , problems and goals ( this is known as self _ actualization). 

f): He has good self__ control _ balances  rationality  and emotionally. 

g): He faces problems and tries to solve them intelligently, i.e., coping with stress and anxiety. 


   Assessment  of mental health  at the population  level may be made by administering  mental  status questionnaires by trained  interviewers. 

3): Social Dimension: 

      Social well _ being implies harmony and integration  within the individual, between each individual  and other members of the 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".

       The social  dimension of health  includes the levels of social skills one possesses, social  functioning  and the ability  to see oneself as a member of a larger society. 


4): 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.

5): Emotional  Dimension: 

   Historically  the mental and emotional dimensions have been seens as one element or as two closely related elements. However, as 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. 


6): 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.

        The importance  of this dimension  is exposed when individuals  suddenly  lose their jobs or are faced with mandatory retirement. 


7): Others : 


          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 

       A glance  at the above  dimensions shows  that there are many " non_ medical " dimensions of health, e.g., social, cultural, educational, etc. These symbolize a huge range of factors to which other sectors besides health  must contribute if all people are indeed to attain a level  of health  that will permit them to lead a socially  and  economically  productive  life.


CONCEPT  OF WELL__ BEING 

The WHO definition of health introduces the concept of " well __ being". The question then arises: what is meant by well _ being? In point of fact, there is no satisfactory  definition of the term " well _ being". 


    Recently , 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 well _ being  ( as expressed by each individual ) is referred to as " quality of life". Let us consider these concepts separately. 


1): Standard of living : 

   The term " 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. 


   A similar definition , corresponding to the above, was proposed by WHO: " Income and occupation, standards of housing sanitation and nutrition, the level of provision of health, educational, recreational and other services may all be used  individually as measures  of socio_ economic  status, and collectively as an index of the " standard of living". 


   There are vast inequalities  in the standard  of living of the people in different  countries of the world. The extent of these differences are usually  measured through the comparison  of per capita  GNP on which the standard of living primarily depends.

2): Level of living :

   The parallel  term for standard  of living used in United National documents is " level of living ". It consists of nine components:  health, food consumption, education,  occupation and working conditions,  housing, social security, clothing, recreation and leisure and human rights.  These objective characteristics are believed to  influence human well _ being. It is considered of the level of living because its impairment  always means impairment of the level of living. 


3): Quality of life 

    Much has been said and written on the quality of life in recent years . It is the " subjective " components of well_ being.

     A recent definition of quality of life is as follows : " a composite measure  of physical, mental and social well_ being as perceived by each individual or by group of individuals __ that is to say, happiness, satisfaction and concerns as health, marriage, family work, self _ esteem, creativity, belongingness and trust in others". 


    It is conceded that a rise in the standard of living of the people  is not enough to achieve satisfaction or happiness. Improvement of quality of life must also be added policy and on reformulation of societal goals to make life more liveable. 


Physical quality of life index ( PQLI) 


      As things stand at present, this important concept of quality  of life is difficult to define and even more difficult to measure. Various attempts have been made to reach one composite index from a number of health indicators. 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. 


    For each component, the performance of individual countries is placed on a scale of 0 to 100, where 0 represents an absolutely defined " worst" performance, and 100 represents an absolutely defined   "best" performance.  The composite index is calculated by averaging the three indicators, giving equal weight to each of them .The resulting PQLI thus also is scaled 0 to 100.

  It may be mentioned that PQLI has not taken per capital GNP into consideration, showing thereby that " money is not everything ".☆☆⬇️


Human Development Index ( HDI) 

    Human development index ( HDI) defined as " a composite index combining indicators representing three dimensions __ longevity ( life expectancy at birth); knowledge ( adult literacy rate and mean years of schooling); and income ( real GDP per capita in purchasing power parity in US dollars)".

      Thus the concept of HDI reflects achievement in  the most basic human capabilities, viz, leading a long life, being knowledgeable and enjoying a decent standard of living . Hence, these three variables have been chosen to represent those dimensions. 


     The HDI values ranges between  0 to 1 . The HDI value for a country  shows the distance that it has already travelled towards maximum possible value to 1, and also allows comparisons with other countries. 

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 .It is thus obvious that health fluctuates within a range of optimum well __  being to various levels of dysfunction, including the state of total dysfunction, namely the death. The transition from optimum health to ill__ health is often gradual, and where ne state ends and the other begins is a matter of judgment. 



         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  :

Health  is multifactorial. The factors which influence health lie both within the individual and externally in the society in which he or she lives. It is a truism to say that what man is and to what diseases he may fall victim depends on a combination of two sets of factors __ his genetic factors and the environmental factors to which he is exposed.  These factors interact and these interactions may be health __ promoting or deleterious. Thus, conceptually, the health of individuals and  whole communities may be considered to be the result of many interactions. 


1): Biological determinants 

      The physical and mental traits of every human being are to some  extent determined by the nature of his genes at the moment of conception. The genetic make __ up is unique in that it cannot be altered  after conception. A number of diseases are now known to be of genetic origin, e.g., chromosomal anomalies, errors of metabolism, mental retardation, some types  of  diabetes partly on the genetic consitution of man. Nowadays, medical genetics offers hope for prevention and treatment of a wide spectrum of diseases, thus the prospect of better medicine and longer, healthier life. A vast field of knowledge has yet to be exploited. It plays a particularly important role in genetic screening and gene therapy. 

2): Behavioural and socio_ cultural conditions:

   The term " lifestyle" is rather a diffuse concept often used to denote " the way people live" , reflecting a whole range of social values, attitudes and activities. It is composed of cultural and behavioral patterns and lifelong personal habits ( e.g., smoking, alcoholism) tha have developed through processes of  socialization. Lifestyle are learnt through social interactions with patents, peer groups, friends and siblings  and through school and mass media.


   Many current __ day health problems especially in the developed countries (e.g., coronary heart disease, obesity, lung cancer,drug addiction) are associated with lifestyle changes. In developing countries such as India where traditional lifestyle still persist, risks of illness and death are connected with lack of sanitation, poor nutrition, personal hygiene, elementary human habits, customs and cultural patterns. 

   It may be noted that not all lifestyles factors are harmful. There are many that can actually promote health. Examples include adequate nutrition, enough sleep, sufficient physical activity, etc. In short, the achievement of optimum health demands adoption of healthy lifestyle. Health is both a consequence of an individual's lifestyle and a factor in determining it.

3): Environment 

    It is an established fact that environment has a direct impact on the physical, mental and social well _ being of those living in it. The environmental factors range from housing, water supply, psychosocial stress and family structure through social and economic  support systems, to the organization of health and social welfare services in the community. 

4): Socio__ economic conditions:

   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 : 

  (i) Economic Status : The per capita GNP  is the most widely accepted  measure of general economic performance. 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 upper socio _ economic groups.


(ii) Education  :  A  second major factor influencing  health status is  education  ( especially female education). The world map of illiteracy closely  coincided with the maps of poverty, malnutrition, illhealth, 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 hea facilities. 


(iii) Occupation : The very state of being employed in productive work promotes health, because  the unemployed usually  show a  higher incidence of illhealth and death .For many, loss of work may mean loss of income and status. It can cause psychological and social change.


(iv) Political  system  : Health is also related to the country's political  system. 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. The percentage  of GNP spent on health  is a quantitative indicator  of political  commitment.

5): Health services :

  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 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 material and child morbidity and mortality. To be effective, the health services  must reach the social periphery, equitably distributed, accessible at a cost the country and community can afford, and socially  acceptable. All these are ingredients of what is now termed " primary  health care", which is seen as the way to better health. 

6): Ageing of the population:

     By the year 2020, the world will be more than one billion people  aged 60 years and over, and more than two__ thirds of them living in developing  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. 


7): Gender 

     The 1990s have witnessed  an increased concertration 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 related condition and the occupational environment. It has brought  about an increased  awareness among policy__ makers of women's health issues and encourages their inclusion in all development plans as a priority. 



8) Other Factors 

  We are witnessing  the transition from post  industrial age to an information age and experiencing the early days of two interconnected revolutions, in information and in communication. The  development of these technologies offers tremendous opportunities in providing an easy and instant access to medical information once difficult  to retrieve. It contributes to dissemination of information worldwide, serving the needs of many physicians,health professionals, biomedical scientists and researchers, the mass media and the public.


    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 standards of living. This would include wages, prepaid medical programmes and family support systems. 

  
   In short, medicine is not the sole contributor to the health and well _ being of population. The potential of inteersectoral contributions to the health of communities is increasingly recognized. 



INDICATORS OF HEALTH : 

  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. 


     Health is multidimensional, and each dimension  is influenced by numerous factors, some known and many unknown. This means we must measure health, therefore, cannot be in terms of a single indicator ; it must be conceived in terms of a profile, employing many  indicators, which may be classified as : 


  ☆  Mortality indicators .

  ☆   Morbidity indicators .

  ☆   Disability rates.

  ☆    Nutritional  status indicators.

  ☆   Health  care  delivery  indicators .

  ☆   Utilization  rates.

  ☆     Indicators of social and mental health. 

☆     Environmental indicators. 

☆  Socia _ economic   indicators. 

 ☆  Indicators of quality of life, and 

 ☆ Other indicators.


1) Mortality  indicators : 

   (a) Crude death rate  : This is considered  a fair indicator of the comparative  health  of the people . It is defined as  the number of deaths per 1000  population  per year in a given community. 


(b) Expectation of life : Life expectancy  at birth is " the average  number of years that will be lived by those born alive into a population if the current age _ specific  mortality rates persist ". Life expectancy at birth is highly influenced  by the infant mortality rate where that is high . Life  expectancy at the age of  5  excludes the influence of child mortality. Life expectancy at birth is used most frequently. It is estimated for  both  sexes separately. An increase  in the expectation of  life is regarded, inferentially, as an improvement  in health status. 


   Life expectancy  is a good indicator  of socio__ economic  development  in general.  As an indicator of long _  term survival,  it can be considered  as a positive health  indicator. It has been adopted as a global health indicator. 

 
(c) Infant mortality  rate : Infant mortality  rate is the ratio of deaths under 1 years 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. It is one of the most universally accepted indicators of the availability, Utilization and effectiveness of health care, particularly perinatal care. 

  
  (d) Child mort rate : Another indicator related to the overall health  status is the early childhood ( 1 __ 4  years) mortality rate.It is defined as the number of death 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. 


(e)  Under __ 5 proportionate  mortality rate : It is the proportion  of total deaths  occurring in the under _ 5 age group. This rate can be used to reflect  both infant and child mortality rates. In communities with poor hygiene, the proportion may exceed 60 per cent.


(f) Maternal ( puerperal ) mortality ratio : Maternal death is defined  as " the death of a women while  pregnant or within 42 days of termination of pregnancy, irrespective of the duration  and site of pregnancy , from  any cause related to or aggravated by the pregnancy or its management but not from accidental  or incidental causes". Maternal ( puerperal) mortality accounts for the greatest proportion of deaths among women of reproductive age in most of the developing world. 


(g) Disease _ specific mortality rate : Mortality rates can be computed for specific diseases. As countries begin to extricate  themselves from the burden of communicable diseases, a number of other indicators such as deaths from cancer, cardiovascular  diseases, accidents, diabetes, etc have  emerged as measures of specific disease problems. 


(h) Proportional mortality rate : The simplest measure of estimating the burden of a disease in the community is proportional mortality rate, i.e., the proportion of all deaths currently  attributed to it. For example coronary heart  disease is the cause of 25 to 30 per cent of all deaths in most western countries. The proportional mortality rate from communicable diseases has been suggested as a  useful status indicator; it indicates the magnitude of preventable mortality. 

   
  Mortality indicators represent the traditional measures of health status. Even today they are probably the most often used indirect indicators  of health.


2): Morbidity indicators:

     To  described health in terms of mortality rates only is misleading . This is because, mortality indicators do not reveal the burden  of ill __ health in a community . Therefore,morbidity indicators are used to supplement  mortality data to describe  the health  status of a population. 


   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  centers, etc


d): Admission, re_ admission  and discharge rates

e): Duration  of stay in hospital , and 

f): Spells of sickness or absence  from work or school. 

3): Disability rates :

    Since death rates have not changed  markedly in recent  years, despite massive health expenditures, disability rates related to illness and injury have come into use to supplement  mortality and morbidity  indicators. 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 

i)  Number of days of restricted activity 

ii) Bed disability  days 

iii) Work __ loss days ( or school loss days ) within a specified period  

(b) 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 house_ work, etc. 

HALE  ( Health _ Adjusted Life Expectancy) : 

The name of the indicator used to measure  healthy life expectancy has been changed from disability _ adjusted life expectancy ( DALE ) to health_ adjusted life  expectancy( HALE). HALE is based on life expectancy for time spent in poor health. It is most easily understood  as the equivalent number of years in full health that a  newborn can expect to live based on current rates of ill _ health and mortality. 

DALY ( Disability _ Adjusted Life Year ) :

DALY is a measure of the burden of disease in a defined population and the effectiveness of the interventions. DALYs  express years of life lost to premature death and year lived with disability adjusted for the severity of the disability. One DALY is " one lost year of healthy life". 

  A " premature " death is defined as one that occurs before the age to which a dying person could have expected to survive if he or she was a member of a standardized model population with a life expectancy at birth equal to that of the world's longest surviving  population , japan.

4) Nutritional status indicators: 

   Nutritional status is a positive health indicator. Three nutritional  status indicators are considered important as indicators of health status. They are : 

 a)   Anthropometric measurements of preschool children, e.g., weight and height, mid_ arm circumference; 

b)  Heights ( and sometimes weights) of children at school entry ; and 

c)  Prevalence  of low birth  weight ( less than 2.5 kg). 

5. Health care delivery indicators :

  The frequently  used  indicators of health care delivery  are :

a)  Doctor _ population ratio 

b)  Doctor _ nurse ratio 

c)  Population _ bed ration 

d)  Population  per health / subcentre, and 

e)  Population  per traditional 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.

6) Utilization rates 


    In order  to obtain additional  information on health status, the extent of use of health services is often investigated. Utilization of services __ or actual  coverage __ is expressed  as the proportion of people  in need of a service  who actually  receives it in given period, usually  a year.

     A few examples  of utilization rates are cited below : 

a)  Proportion of infants  who are " fully  immunized " against  the 6 EPI diseases. 

b)  Proportion of pregnant women who receive antenatal  care, or have their deliveries supervised  by a trained birth attendant. 

c)  Percentage  of the population  using the various  methods of family  planning. 

d)  Bed _ occupancy rate ( i.e., average daily in__ patient census / average  number  of beds).

e) Average length  of stay ( i.e., days of care rendered / discharges ), and 

f)   Bed turn__ over ratio (i.e., discharges/ average beds).

7) 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 acts of violence and other crime; road traffic  accidents, juvenile  delinquency; alcohol and drug abuse ; smoking; consumption of tranquilizers; obesity, etc. To these may be added family  violence , battered _ baby and abandoned  youth in the neighborhood. These social  indicators provide a guide to social  action for improving the health of the people.

8)   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. 

9)  Socio _ economic  indicators:

  These indicators do not directly measure  health. Nevertheless , they are of great importance in the interpretation of the indicators of health care. These include : 

a)   Rate of population increase 

b) Per capita GNP

c) Level of unemployment 

d) Dependency  ratio

e)  Literacy rates,  especially  female literacy rates

f) Family  size 

g)  Housing  : the number of persons per room, and 

h)  Per capita " calorie " availability 

10) Health policy indicators 

  The single most important  indicator of political  commitment is " allocation of adequate resources ". The relevant indicators are :

(i) Proportion of GNP spent on health services 

(ii) Proportion of GNP spent  on health _ related activities ( including  water supply  and  sanitation,  housing  and  nutrition, community  development) and 

(iii) proportion  of total health  resources  devoted  to primary  health  care. 

11) Indicators  of quality  of life 


   Increasingly, mortality and morbidity data have been questioned as to whether they fully reflect the health status of a population. The previous  emphasis on using  increased  life expectancy as an indicator of  health is no longer considered adequate, especially in developed countries, and attention  has shifted more toward  concern about the quantity of life enjoyed by individuals and communities. ☆☆⬆️

12) Other indicators series 

 (a) Social  indicators : Social indicators, as defined by the United Nation Statistical  Office, have been divided into 12 categories  : Population  ; family formation , families  and households; learning   and   educational services ; earning  activities  ; distribution of income, consumption,  and  accumulation; services  and nutrition;  housing and  its  environment  ; public order and safety ; time use ; leisure  and  culture; social   stratification  and mobility. 


(b) Basic  needs  indicators  :Basic  needs indicators are used by ILO . Those  mentioned in " Basic  needs  performance " include  calorie consumption; access to water; life expectancy; deaths due to disease; illiteracy,  doctors and nurse per population; rooms  per person;  GNP  per capita .

(c) "Health  for All "  indicators: For monitoring progress towards the goal of Health  for All by 2000 A.D., the WHO had listed the following  four categories  of indicators 



(d) Millennium Development  Goals Indicators : The Millennium  Development  Goal adopted  by the United in the year 2000 provides an opportunity for concerted action to improve global health. The health related  goals and their  indicators of progress are listed in 


    The search for indicators  associated with or casually  related to health continues. It will be seen from the above that there is no single comprehensive indicator of a nation's  health. Each available indicator reflects an aspect of health . The ideal index which combines the effect of a number  of components measured independently is yet to be developed. 


  ☆B) CONCEPT OF DISEASE : 

   The WHO has defined health but not disease. This is because  disease has many shades ( " spectrum of disease") ranging from inapparent ( subclinical) cases  to severe manifest  illness. Some diseases commence acutely ( e.g., food poisoning), and some insidiously (e.g., mental diseases, a " carrier" state occurs  in  which  the individual  remains  outwardly  healthy, and is able  to infect  others (e.g.,gtyphoid fever). In some instances, the same organisms may cause more than one clinical manifestation ( e.g.,  streptococcus). In some cases, the same disease may be caused by more than one organisms ( e.g.,diarrhoea). Some diseases have a short course , and some a prolonged course . It is easy to determine illness when the signs and symptoms are manifest, but in many diseases the border line between   normal and abnormal is indistinct as in the case of diabetes , hypertension and mental illness. The end_ point  or final outcome of disease is variable __ recovery disability   or death  of the host.
    

  The clinician  sees  people who are  ill rather than the diseases which he must  diagnose  and  treat.  However,it  is  possible to be victim of  disease  without  feeling ill, and to be  ill without  signs of physical impairment. In short, an adequate  definition of disease is  yet to be found __ a definition  that is  satisfactory or acceptable to the epidemiologists, clinician, sociologist and  the statistician. 

CONCEPT OF CAUSATION  

Factors responsible  for the spread of communicable diseases 


   For  the  occurrence of  a disease in man three  things  are required,  namely  AGENT,  HOST  and  ENVIRONMENT.  These three  factors  are referred to as epidemiological triad .Disease cannot  occur  in  the absence  of any  one  of  these three factors. 

Agent Factors 

     One of  the  first  requirements for  the occurrence of  disease  is  a  disease agent. The disease agent may  be living  or non_ living . The disease agents  have been classified  into 5  broad groups : 

  (a) Biological  agents : These are the living  agents, e.g.,  viruses,  bacteria, fungi, protozoan, etc. These are found  in  the reservoir  of  infection  ( e.g., man, animal, insect,  soil  ).


 (b) Nutrient agents :  These  are proteins, fats, carbohydrates, vitamins,  minerals and water.  An excess  or  deficiency  of nutrients may lead  to nutritional diseases. 


(c)  Physical  agents : These are heat, cold, pressure, radiation, electricity. 

(d) Chemical  agents : These may be  metals (e.g.,  lead), fumes, dusts,  gases, etc.

(e) Mechanical  agents : Chronic  friction and other  mechanical  forces may cause trauma,  injuries  and fractures. 


Host   factors 


  The  host __ related   factors  are :

(a)  Age : Certain diseases are more frequent in certain age groups than in others,  e.e.g.measles  in  childhood, cancer in  middle age, atherosclerosis in   old  age. 


(b)  Sex  : There  are   sex   differences in    disease occurrence.  Diabetes is  more  frequent in   females;  and  heart  disease in  males. No  satisfactory explanation has  been  given  for  this  difference.



(c)  Heredity  : Harmful  genes in  the  constitution many  give   rise  to  disease, e.g., haemophilia, colour  blindness, albinism. A number of congenital defects (e.g., cleft palate, hare _ lip, spina  bifida) are due  to genetic factors . Essential  hypertension, diabetes, mental diseases are  all  thought  to be  due  to genetic  pre__ disposition. 


(d)  Nutrition  : Poor  nutrition is  frequently ass with nutritional deficiency diseases (e.g., kwashiorkor, anaemia). There  are  also  diseases  associated  with  over _ eating such  as  obesity  and  diabetes. 


(e)  Occupation  : The  occupation of  the host may predispose  him to certain  occupational  diseases, e.g., lead poisoning, silicosis, accidents. 

(f)  Customs  and  habits : Certain customs are prejudicial to health. Smoking is  related to oral and  lung  cancer; open  air defecation, by causing  soil  pollution, favours, the  spread   of  intestinal parasites. 


(g)  Human  behaviour  : Lack of  physical  exercise,  indulgence in   alcohol  and certain  drugs  are known  to  affect  health  adversely. 


Environmental factors  

    A healthy  environment  is  crucial for the health  and well_ being of individuals  and  communities. For descriptive  purposes, environment is  divided into three components:


(a)  Physical environment : Much of  the ill_ health in India  is due to poor environment __ unsafe  water, contaminated soil, poor housing, lack of  disposal facilities for human excreta  and solid  wastes. 

(b) Biological Environment : The  causes of disease may be found in the biological environment, e.g., animals, insects, rodents, etc. 

(c) Social Environment : The  customs, habits, culture, education, standard of  living are all implicated in  disease occurrence directly or indirectly

Risk factors:

   For many diseases, the disease "agent"  is  still unidentified, e.g., coronary heart disease, cancer, peptic ulcer, mental illness etc. Where the disease agent is not firmly established, the aetiology is generally discussed in terms of " risk factors ". Risk factors associated with some major disease.



Risk groups 

Another approach developed by WHO is to identify precisely the " risk groups " or " target groups " ( e.g., at __ risk mothers, at __ risk infants, at__ risk families,  chronically ill  handicapped, elderly) in the population by certain defined criteria and direct appropriate action to them first. This  is known as the " risk approach ". WHO has been using  the risk approach in MCH services since a long time.



Disease cycle :

  The course of most communicable diseases is marked by certain stages. These  are illustrated. These stages are 


(1) Incubation Period : This is the time interval between the entry of the disease agents in the body and manifestation of clinical signs and symptoms. 


(2) Prodromal Period : This is a short period  ranging  from 1 to 4 days, and  is marked  by vague signs and  symptoms. Clinical diagnosis is usually not possible. 


3) Fastigium : This represents the height of the disease. Signs  and symptoms are clear_ cut .The patient is  confined  to bed. Clinical  diagnosis is possible. 


4)  Defervescene : The patient begins to feel  better ; the body defences ( immunity) begin  to respond.  


5) Convalescence : The  patient's recovery is established; he is improving fast.


6) Defection  : The  patient recovers from  illness. 

Spectrum of disease

  Just  as  the colours of a rainbow vary from one end to the other, the severity of disease varies from inapparent or " sub_ clinical " cases on one hand to very severe and fatal cases on the other. This concept  is known as " spectrum  of disease " as shown below : 


            Subclinical cases

          Extremely  mild cases
       
         Mild cases
        
        Moderately severe cases 
  
        Severe cases 
        
         Death 

    The   same disease may be mild in one individual and very severe in  another . In some  individuals, may  remain  subclinical and in others overt. From   the point of view of spreading the  disease, the subclinical and mild  cases may be  a  greater danger  to  the community than Frank clinical cases. 

Iceberg of  disease 

   A concept  closely related to  the  spectrum of  disease is   the  concept of the iceberg phenomenon of disease. According to this  concept, disease in  a community may be compared  with an iceberg. The floating tip of the  iceberg represents what the physician sees  in   the community,  i.e., clinical cases. The  vast  submerged portion of the iceberg represents the  hidden  mass of  disease, i.e., latent, inapparent, presymptomatic  and undiagnosed cases and carrier  in the community . The  " waterline " represents the demarcation between apparent and inapparent disease.



  In  some  disease (e.g.,  hypertension, diabetes, anaemia, malnutrition, mental illness) the unknown morbidity (i.e., the submerged portion of  the iceberg) far exceeds the known morbidity. The hidden part of  the iceberg thus  constitutes an important, undiagnosed reservoir of  infection or disease in  the  community, and  its detection and control is a challenge to modern techniques in  preventive medicine. 

(☆☆C)  CONCEPTS OF CONTROL : 

Disease control  :

     The term " disease  control  "  describes ( ongoing) operation aimed  at reducing: 

i)  The  incidence of disease 

ii)  The  duration  of disease, and consequently the  risk of transmission 

iii)  The  effects  of  infection, including both the physical and psychological complications:  and 

iv)  The financial burden to the community. 

  
  Control  activities may  on  primary prevention or  secondary prevention, most control Programmes combine the two .The concept of tertiary prevention is comparatively less  relevant to control   efforts. 

Disease elimination : 

      Between  control  and eradication, an intermediate goal has been described, called " regional elimination ". The  term  of  " 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. Regional elimination is now seen  as an important precursor of eradication. 


 Disease eradication: 

    Eradication literally means to " tear  out by roots" .  Eradication of disease implies termination of  all transmission  of  infection  by extermination of the infectious agent. As the name  implies, eradication is an absolute process, and not a relative goal. It is " all or none phenomenon ".. The word eradication is reserved to cessation of infection and disease from the whole world.

        Today, smallpox is  the only  disease that has been  eradicated. During  recent years three diseases have been seriously advanced as candidates for global eradication within the foreseeable future: polio, measles and dracunculiasis . Of these the goal  of eradication of polio is almost  in sight.

Monitoring and  surveillance  : 

i) Monitoring 

   Monitoring  is " the performance and  analysis  of  routine  measurements aimed at detecting  changes  in  the environment or  health status  of population". Thus we have monitoring of air pollution, water quality, growth  and  nutritional status, etc. It also refers  to on__ going measurement  of performance of a health service or a health professional, or of the extent to which patients comply with or adhere to advice from health professionals. 

ii)  Surveillance 

       Surveillance  is defined in many ways. The main objectives  of surveillance are:

(a)  To provide information  about new and changing  trends in  the health status of a population, e.g., morbidity, mortality, nutritional status or other indicators and environmental hazards, health practices and other factors that may affect  health; 


(b)  To  provide feed __ back which may be expected to modify the policy and the system itself and lead to redefinition of  objectives, and 

(c) Provide  timely  warning  of public  health  disasters so that interventions can be mobilized. 

Sentinel  Surveillance:

    No routine  notification  system can identify  all cases  of infection  or disease. A method  for  identifying the missing  cases and thereby supplementing the notified cases is required. This is known as " sentinel surveillance". The sentinel  data is extrapolated to the entire  population to estimate  the disease prevalence  in the total  population. 


Evaluation of control:

     Evaluation  is  the process by which results  are compared  with the intended objectives, or more simply  the assessment of now well  a programme is  performing. Evaluation should always  be considered during the planning  and implementation stages of a programme  or activity. 


CONCEPTS OF  PRESERVATION 

Levels of prevention:

     In  modern day, the concept of prevention has  become  broad _ based .It has  become customary to define  prevention  in  terms  of 3  levels  : 



a.  Primary  Prevention 

b. Secondary Prevention 

c. Tertiary  Prevention 


a. Primary  Prevention 

Primary  Prevention can be defined as " action taken prior to  the onset of disease,  which removes the possibility that a disease will ever occur ". The  specific interventions are : 

         (a)  health  promotion 

        (b)   Specific  Protection 


Health Promotion 

       We can prevent a number  of diseases such as cholera, typhoid fever, tuberculosis and nutritional diseases by merely promoting the health of the individual and community. The measures by which we may achieve this have been discussed at length. Briefly, they include adequate nutrition, Provision of safe water supply, facilities for the safe disposal of human excreta and other human wastes, personal hygiene, health education, physical education, periodic health screening and improving the quality of life of the people. 

Specific Protection 

     By specific protection we mean preventing specific diseases by specific measures. Examples include prevention of EPI diseases ( tuberculosis, diphtheria, pertussis, tetanus, polio, and measles) by immunization; prevention of xerophthalmia by administration of  vitamin A; prevention of accidents in factories and industries by use of protective devices. Of these immunization is the most widely used intervention in the prevention of disease. 

  Primary prevention is  a desirable goal.It is worthwhile to recall the fact  that the developed countries succeeded in eliminating most of the infectious diseases by primary prevention are being applied to the prevention of chronic diseases ( i.e., cessation of smoking, dietary control measures, physical exercise, etc).


 Secondary Prevention :

  Secondary prevention may be defined  as "action which halts the progress  of a disease  at its  incipient  stage and prevents  complications". The specific  interventions are : 

(a) Early  diagnosis ( screening  tests,  case  funding  programmes).

(b)  Adequate treatment 

  We  do not have  vaccines to prevent all diseases .For diseases of  this category ( e.g., leprosy, syphilis, malaria ) early  diagnosis  and treatment  is  the only solution. The  earlier a  disease is  diagnosed  the batter it is form  the point   of  view  of preventing  the  occurence of further cases  in the community. It is like putting  out the " spark" of  fire  rather than allowing  it  to spread and call   the fire  brigade  later .

Tertiary  Prevention 

     When the disease process has advanced beyond its early stages, it is still  possible to accomplish prevention  by what may be called " tertiary  Prevention " Tertiary Prevention is  defined as " all measures available to reduce  or limit  impairments and  disabilities, minimise suffering caused by existing departures from good health and to promote the patients adjustment to irremediable conditions." The specific  interventions are : 

(a) Disability  limitation 

(b) Rehabilitation 

   For  example  in Leprosy we try to limit disability by early adequate treatment and plastic surgery. This  is  followed by rehabilitation. Rehabilitation has  the following aspects:


(a) Functional  rehabilitation __ restoration of function


(b) Vocational rehabilitation __  Restoration of the capacity  to earn  a livelihood. 


(c) Social  Rehabilitation __ Restoration of family  and  Social  relationships. 


(d)  Psychological rehabilitation __ Restoration of personal  dignity   and confidence. 

   In recent years, rehabilitation medicine has emerged  as  a medical speciality. It  involves the  disciplines of  physiotherapy occupational therapy, speech therapy, audiology, psychology,  education,  social  work,  Vocational   guidance  and     placement services,  etc. The  purpose of rehabilitation ' to make  productive  people out of non__ productive  people'.


International Classification of diseases:

   The purpose  of  international classification of Diseases ( ICD) is  to contribute to a uniform classification that can  be used throughout the world  to make accurate comparisons of morbidity and mortality data for decision__ making in  Prevention, in management of health care and in facilitating research on  particular health problems. 




























  





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