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  1. Unit I: Health and Disease
  2. CONCEPT OF HEALTH Health has evolved over the centuries as a concept from an individual concern to a worldwide social goal and encompasses the whole quality of life. – Biomedical concept : Traditionally, health has been viewed as an "absence of disease", and if one was free from disease, then the person was considered healthy. This concept, known as the "biomedical concept" has the basis in the "germ theory of disease" which dominated medical thought at the turn of the 20th century. The medical profession viewed the human body as a machine, disease as a consequence of the breakdown of the machine and one of the doctor's task as repair of the machine.
  3. • Ecological concept : Deficiencies in the biomedical concept gave rise to other concepts. The ecologists put forward an attractive hypothesis which viewed health as a dynamic equilibrium between man and his environment, and disease a maladjustment of the human organism to environment. Dubos defined health saying : "Health implies the relative absence of pain and discomfort and a continuous adaptation and adjustment to the environment to ensure optimal function".
  4. • Psychosocial concept : Contemporary developments in social sciences revealed that health is not only a biomedical phenomenon, but one which is influenced by social, psychological, cultural, economic and political factors of the people concerned. These factors must be taken into consideration in defining and measuring health. Thus health is both a biological and social phenomenon.
  5. • Holistic concept: The holistic model is a synthesis of all the above concepts. It recognizes the strength of social, economic, political and environmental influences on health. It has been variously described as a unified or multidimensional process involving the well-being of the whole person in the context of his environment. This view corresponds to the view held by the ancients that health implies a sound mind, in a sound body, in a sound family, in a sound environment. The holistic approach implies that all sectors of society have an effect on health, in particular, agriculture, animal husbandry, food, industry, education, housing, public works, communications and other sectors
  6. DEFINITION OF HEALTH • WHO definition The widely accepted definition of health is that given by the World Health Organization (1948) in the preamble to its constitution, which is as follows : "Health is a state of complete physical, mental and social well- being and not merely an absence of disease or infirmity" In recent years, this statement has been amplified to include the ability to lead a "socially and economically productive life". The WHO definition of health has been criticized as being too broad. Some argue that health cannot be defined as a "state" at all, but must be seen as a process of continuous adjustment to the changing demands of living and of the changing meanings we give to life. It is a dynamic concept. It helps people live well, work well and enjoy themselves
  7. • Operational definition of health "operational definition" has been devised by a WHO study group. In this definition, the concept of health is viewed as being of two orders. In a broad sense, health can be seen as '·a condition or quality of the human organism expressing the adequate functioning of the organism in given conditions, genetic or environmental".
  8. • In a narrow sense - more useful for measuring purposes - health means: – there is no obvious evidence of disease, and that a person is functioning normally, i.e. , conforming within normal limits of variation to the standards of health criteria generally accepted for one's age, sex, community, and geographic region; and – the several organs of the body are functioning adequately in themselves and in relation to one another, which implies a kind of equilibrium or homeostasis - a condition relatively stable but which may vary as human beings adapt to internal and external stimuli.
  9. 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.
  10. 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.
  11. • Physical dimension – The state of physical health implies the notion of '·perfect functioning" of the body. – It conceptualizes health biologically as a state in which every cell and every organ is functioning at optimum capacity and in perfect harmony with the rest of the body. – The signs of physical health in an individual are: "a good complexion, a clean skin, bright eyes, lustrous hair with a body well clothed with firm flesh, not too fat, a sweet breath, a good appetite , sound sleep, regular activity of bowels and bladder and smooth, easy, coordinated bodily movements. All the organs of the body are of unexceptional size and function normally; all the special senses are intact; the resting pulse rate, blood pressure and exercise tolerance are all within the range of "normality'' for the individual's age and sex. In the young and growing individual there is a steady gain in weight and in the future this weight remains more or less constant at a point about 5 lbs (2.3 kg) more or less than the individual's weight at the age of 25 years.
  12. • Mental dimension Mental health is not mere absence of mental illness. Good mental health is the ability to respond to the many varied experiences of life with flexibility and a sense of purpose. More recently, mental health has been defined as "a state of balance between the individual and the surrounding world, a state of harmony between oneself and others, a coexistence between the realities of the self and that of other people and that of the environment"
  13. • characteristics as attributes of a mentally healthy person: – a mentally healthy person is free from internal conflicts; he is not at "war" with himself. – he is well-adjusted, i.e., he is able to get along well with others. He accepts criticism and is not easily upset. – he searches for identity. – he has a strong sense of self-esteem. – he knows himself: his needs, problems and goals (this is known as self-actualization). – he has good self-control-balances rationality and emotionality. – he faces problems and tries to solve them intelligently, i.e., coping with stress and anxiety.
  14. • Social dimension Social well-being implies harmony and integration within the individual, between each individual and other members of society and between individuals and the world in which they live. It has been defined as the "quantity and quality of an individual's interpersonal ties and the extent of involvement with the community''
  15. • Spiritual dimension Proponents of holistic health believe that the time has come to give serious consideration to the spiritual dimension and to the role this plays in health and disease. Spiritual health in this context, refers to that part of the individual which reaches out and strives for meaning and purpose in life. It is the intangible "something" that transcends physiology and psychology. As a relatively new concept, it seems to defy concrete definition. It includes integrity, principles and ethics, the purpose in life, commitment to some higher being and belief in concepts that are not subject to "state of the art'' explanation
  16. • Emotional dimension Historically the mental and emotional dimensions have been seen as one element or as two closely related elements. However, as more research becomes available a definite difference is emerging. Mental health can be seen as "knowing" or "cognition" while emotional health relates to "feeling". Experts in psychobiology have been relatively successful in isolating these two separate dimensions. With this new data, the mental and emotional aspects of humanness may have to be viewed as two separate dimensions of human health
  17. • 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.
  18. 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.
  19. • 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.
  20. Determinants of Health
  21. Epidemiological triad
  22. Natural History of disease
  23. MODES OF INTERVENTION • defined as any attempt to intervene or interrupt the usual sequence in the development of disease in man. This may be by the provision of treatment, education, help or social support. – Health promotion – Specific protection – Early diagnosis and treatment – Disability limitation – Rehabilitation
  24. Health promotion • Health promotion is "the process of enabling people to increase control over, and to improve health “ • It is not directed against any particular disease, but is intended to strengthen the host through a variety of approaches (interventions) – health education – environmental modifications – nutritional interventions – lifestyle and behavioural changes
  25. Specific protection • To avoid disease altogether is the ideal but this is possible only in a limited number of cases. – immunization – use of specific nutrients – chemoprophylaxis – protection against occupational hazards – protection against accidents – protection from carcinogens – avoidance of allergens – the control of specific hazards in the general environment, e.g., air pollution, noise control • control of consumer product quality and safety of foods, drugs, cosmetics, etc.
  26. Early diagnosis and treatment • A WHO Expert Committee defined early detection of health impairment as '·the detection of disturbances of homoeostatic and compensatory mechanism while biochemical, morphological, and functional changes are still reversible. " Thus, in order to prevent overt disease or disablement, the criteria of diagnosis should, if possible, be based on early biochemical, morphological and functional changes that precede the occurrence of manifest signs and symptoms. This is of particular importance in chronic diseases.
  27. • The earlier a disease is diagnosed and treated the better it is from the point of view of prognosis and preventing the occurrence of further cases (secondary cases) or any long- term disability
  28. Disability limitation • When a patient reports late in the pathogenesis phase, the mode of intervention is disability limitation. The objective of this intervention is to prevent or halt the transition of the disease process from impairment to handicap. • Concept of disability
  29. • Impairment : An impairment is defined as "any loss or abnormality of psychological, physiological or anatomical structure or function". e .g., loss of foot, defective vision or mental retardation. An impairment may be visible or invisible, temporary or permanent, progressive or regressive. Further, one impairment may lead to the development of "secondary" impairments as in the case of leprosy where damage to nerves (primary impairment) may lead to plantar ulcers (secondary impairment).
  30. • Disability : Because of an impairment, the affected person may be unable to carry out certain activities considered normal for his age, sex, etc. This inability to carry out certain activities is termed "disability". A disability has been defined as ''any restriction or lack of ability to perform an activity in the manner or within the range considered normal for a human being".
  31. • Handicap : As a result of disability, the person experiences certain disadvantages in life and is not able to discharge the obligations required of him and play the role expected of him in the society. This is termed "handicap~, and is defined as "a disadvantage for a given individual, resulting from an impairment or a disability, that limits or prevents the fulfilment of a role that is normal (depending on age, sex, and social and cultural factors) for that individual" .
  32. • Rehabilitation: Rehabilitation has been defined as "the combined and coordinated use of medical, social, educational and vocational measures for training and retraining the individual to the highest possible level of functional ability“. It includes all measures aimed at reducing the impact of disabling and handicapping conditions and at enabling the disabled and handicapped to achieve social integration. Social integration has been defined as the active participation of disabled and handicapped people in the mainstream of community life
  33. INDICATORS OF HEALTH • A question that is often raised is: How healthy is a given community ? Indicators are required not only to measure the health status of a community, but also to compare the health status of one country with that of another; for assessment of health care needs; for allocation of scarce resources; and for monitoring and evaluation of health services, activities, and programmes. Indicators help to measure the extent to which the objectives and targets of a programme are being attained.
  34. Characteristics of indicators • Indicators have been given scientific respectability; for example ideal indicators – should be valid, i.e., they should actually measure what they are supposed to measure; – should be reliable and objective, i.e., the answers should be the same if measured by different people in similar circumstances; – should be sensitive, i.e., they should be sensitive to changes in the situation concerned, – should be specific, i.e., they should reflect changes only in the situation concerned, – should be feasible, i.e., they should have the ability to obtain data needed, and; – should be relevant, i.e., they should contribute to the understanding of the phenomenon of interest.
  35. • Mortality indicators • Morbidity indicators • Disability rates • Nutritional status indicators • Health care delivery indicators • Utilization rates • Indicators of social and mental health • Environmental indicators • Socio-economic indicators • Health policy indicators • Indicators of quality of life, and • Other indicators.
  36. Mortality indicators • Crude death rate • Life expectancy at birth • Age-specific death rates • Infant mortality rate • Child death rate • Maternal (puerperal) mortality rate • Disease-specific mortality rate • Case fatality rate ……
  37. Morbidity indicators • incidence and prevalence • notification rates • attendance rates at out-patient departments, health centres, etc. • admission, readmission and discharge rates • duration of stay in hospital, and • spells of sickness or absence from work or school.
  38. Disability indicators • Event-type indicators – Number of days of restricted activity – Bed disability days – Work-loss days (or school-loss days) within a specified period • Person - type indicators – Limitation of mobility: For example, confined to bed, confined to the house, special aid in getting around either inside or outside the house. – Limitation of activity: For example, limitation to perform the basic activities of daily living (ADL)- e.g., eating, washing, dressing, going to toilet. moving about, etc; limitation in major activity, e.g., ability to work at a job, ability to housework, etc.
  39. Nutritional status indicators • anthropometric children, e.g., circumference; measurements of weight and height. preschool mid-arm • heights (and sometimes weights) of children at school entry; and • prevalence of low birth weight (less than 2.5 kg).
  40. Health care delivery indicators • Doctor- population ratio • Doctor-nurse ratio • Population-bed ratio • Population per health/subcentre, and • Population per trained birth attendant.
  41. Utilization rates • proportion of infants who are "fully immunized‘” • proportion of pregnant women who receive antenatal care, or have their deliveries supervised by a trained birth attendant. • percentage of the population using the various methods of family planning. • bed-occupancy rate (i.e., average daily in-patient census/average number of beds). • average length of stay (i.e., days of care rendered/ discharges), and • bed turnover ratio (i.e., discharges/average beds).
  42. 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
  43. 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.
  44. Socio-economic indicators • rate of population increase • per capita GNP • level of unemployment • dependency ratio • literacy rates, especially female literacy rates • family size • housing: the number of persons per room, and • per capita "calorie" availability.
  45. Health policy indicators • proportion of GNP spent on health services • proportion of GNP spent on healthrelated activities (including water supply and sanitation, housing and nutrition, community development), and • proportion of total health resources devoted to primary health care.
  46. Indicators of quality of life • physical quality of life index
  47. Levels of prevention • Primodial • Primary • Secondary • Tertiary