MAN AND MEDICINE
Preventive Medicine
The science and art of preventing disease, prolonging life and promoting health and efficiency through organized community effort.
Social Medicine
Study of man as a social being in his total environment. Role of social factors in disease etiology.
Community Medicine
Deals with populations and comprises those doctors who try to measure the needs of the population, both sick and well, who plan and administer services to meet those needs, and those who are engaged in research and teaching in the field.
Health for All
In 1977, the 30th World Health Assembly resolved that the main social target of governments and WHO in the coming decades should be the attainment by all citizens of the world by the year 2000 of a level of health that will permit them to lead a socially and economically productive life—HFA 2000.4
Primary Health Care
It is the key to achieve HFA 2000 (is essential health care made universally accessible to individuals and acceptable to them, through their full participation and at a cost the community and country can afford).
CONCEPTS 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.
Dimensions of Health
(1) Physical, (2) Mental, (3) Social, (4) Spiritual, (5) Emotional, (6) Vocational, (7) Others.
Physical Dimension
State of perfect functioning of the body—every cell and organ functioning at optimum capacity.
Mental Dimension
Mental health is the ability to deal with many varied experiences of life with flexibility and a sense of purpose.
Psychosomatic diseases, e.g. hypertension, peptic ulcer, bronchial asthma. Major mental diseases, e.g. depression, schizophrenia have a biological component.
Social Dimension
Man and his inter-relationship with other members of the society.
Spiritual Dimension
The role of God in health. Studies have shown that those who believe in prayer, God, heal faster and their duration of stay in hospital is decreased.5
Emotional Dimension
It relates to feeling—joy, happiness, worry, grief, fear, anger.
Vocational Dimension
Work can promote health if it is fully adapted to human goals, capacities and limitations and leads to satisfaction and increased self-esteem.
Others
Philosophical dimension, socioeconomic dimension, cultural dimension, environmental dimension, educational dimension, nutritional dimension, curative dimension, preventive dimension.
Physical Quality of Life Index
Physical quality of life index (PQLI) is an indicator of quality of life.
It comprises three indicators: (1) Infant mortality, (2) Life expectancy at age one, and (3) Literacy.
For each component, the performance of individual countries is placed on a scale of 0–100 where 0 represents worst performance and 100 represents best performance. By averaging the three indicators, the composite index is calculated.
Gross national product (GNP) is not considered in PQLI, showing that money is not everything.
Middle East countries with high per capita income have less PQLI than Sri Lanka and Kerala state where there is low per capita income but high PQLI. Ultimate objective is to attain PQLI 100.
Human Development Index
It comprises three indicators: (1) Longevity (life expectancy at birth), (2) Knowledge (adult literacy rate and mean years of schooling) and (3) Income (real GDP per capita in US $).
HDI values range between 0 and 1.
For the indicators, maximum and minimum values have been established.
Life expectancy at birth: 25 years and 85 years.
Adult literacy rate: 0% and 100%
Combined gross enrollment ratio = 0% and 100%
Real GDP per capita = $ 100 and $ 40,000
Individual indices can be calculated by formula:
e.g. India:
Life expectancy 62.6 years
Health and Development
Health and development are interlinked with one another. It was seen that economic development alone can not solve the problems, e.g. poverty, hunger, malnutrition and disease. Whereas noneconomic issues, e.g. education, productive employment, housing, equity, freedom and dignity, human welfare are important in development strategies.7
For example, Sri Lanka, Costa Rica and state of Kerala in India show that health forms part of development.
Kerala State
It has demonstrated that with strong political commitment to equitable socioeconomic development high levels of health can be achieved even on modest levels of income. Literacy, especially female literacy has played a key role in improving the health situation, by improving utilization of health services, transport network improved, land reforms promoted. It has shown that good health at low cost is attainable by poor countries but requires major political and social commitment.
Health Development
The process of continuous progressive improvement of the health status of a population.
Indicators of Health (Health Indicators)
Health is multidimensional, therefore measurement is also multidimensional.
(1) Mortality indicators, (2) Morbidity indicators, (3) Disability rates, (4) Nutritional status indicators, (5) Health care delivery indicators, (6) Utilizations rates, (7) Indicators of social and mental health, (8) Environmental indicators, (9) Socioeconomic indicators, (10) Health policy indicators, (11) Quality of life indicators, (12) Other indicators.
- Mortality indicators:
- Crude death rate—Number of deaths per 1000 population per year in a given community.
- Expectation of life—Average number of years that will be lived by those born alive into a population if the current age specific mortality rates persist.Males 64.1; Females 65.4.
- Infant mortality rate—Ratio of deaths under 1 year of age in a given year to the total no. of live births in the same year expressed as a rate per 1000 live births (58/1000 live births).
- Child mortality rate—Number of deaths 1–4 years in a given year, per 1000 children 1–4 years.
- Under 5 years mortality rate—Annual no. of deaths of children under 5 years expressed as a rate per 1000 live births.
- Maternal mortality rate
- Disease specific mortality—Mortality rate computed for specific diseases, e.g. TB.Specific death rate due to TB =
- Proportional mortality rate—Proportion of all deaths currently attributed to it, e.g. coronary heart disease is the cause of 25–30% of all deaths in western countries.
- Morbidity indicators:
- Incidence and prevalence
- Notification rates
- Attendance rates at OPDs, health centers
- Admission, readmission, discharge rates
- Duration of stay in hospital
- Spells of sickness or absence from work or school.
- Disability rates:
- Event type indicators:
- No. 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, e.g. confined to bed, confined to house, special aid in getting around inside or outside house.
- Limitation of activity, e.g. limitation to perform ADL—activities of daily living—eating, washing, dressing, going to toilet, moving about; limitation of major activity—ability to work, ability to do house work.
Sullivan's index: Expectation of life free of disability calculated by subtracting from life expectancy the probable duration of bed disability and inability to perform major activities, according to cross-sectional data from population surveys.For example, USA 70.2 expectation of life and Sullivan's index 64.9Health adjusted life expectancy (HALE)The equivalent no. of years in full health that a newborn can expect to live based on current rates of ill health and mortality.Disability adjusted life year (DALY)DALY measures the burden of disease in a defined population and the effectiveness of interventions. DALYs express years of life lost to premature death and years lived with disability. - Nutritional status indicators:
- Prevalence of low birth weight
- Anthropometric measurements of preschool children
- Heights, weights of children at school entry.
- Health care delivery indicators:
- Doctor-population ratio
- Doctor-nurse ratio
- Population-bed ratio
- Population per health center/subcenter
- Population per traditional birth attendant.
- Utilization rates: Proportion of people in need of service who actually receive it in a given period, usually a year. For example, proportion of infants fully immunized against 6 EPI diseases, proportion of pregnant women who receive antenatal care or have deliveries by trained birth attendant, percentage of population using various methods of family planning, bed occupancy rate, average length of stay, bed turn-over ratio.
- Indicators of social and mental health: Indirect measures— suicide, homicide, family violence, battered baby syndrome, battered wife syndrome, road traffic accidents, juvenile delinquency, alcohol abuse, smoking, drug abuse, consumption of tranquilizers, obesity.
- Environmental indicators: Proportion of population having access to safe water and sanitation, indicators of air pollution, water pollution, radiation, solid wastes, noise, exposure to toxic substances in food or drink.
- Socioeconomic indicators: Indirect indicators of health—Rate of population increase, per capita GNP, level of unemployment, dependency ratio, literacy especially female literacy rates, family size, housing: no. of persons per room, per capita calorie availability.
- Health policy indicators: Proportion of GNP spent on health services, proportion of GNP spent on health-related activities (water, sanitation, housing, community development, nutrition).
- Proportion of total health resources spent on primary health care.
- Quality of life indicators: Physical quality of life index (PQLI)—Infant mortality, life expectancy at age one and literacy.
- Other indicators:
- Social indicators—Population, family formation, learning and educational services, earning activities, distribution of income, social security, welfare services, health services and nutrition, housing, environment, leisure and culture.
- Basic needs indicators—Calorie consumption, access to water, life expectancy, deaths due to disease, illiteracy, doctors and nurses per population, rooms per person, GNP per capita.
- HFA indicators.Indicators for monitoring progress towards health for all:
- Health policy indicators:
- Political commitment to HFA
- Resource allocation
- Health services—equity of distribution
- Community involvement
- Organizational framework and managerial process.
- Social and economic indicators:
- Rate of population increase
- GNP or GDP
- Income distribution
- Work conditions
- Literacy rate
- Housing
- Food availability.
- Indicators for provision of health care:
- Availability
- Accessibility
- Utilization
- Quality of care.
- Health status indicators:
- Low birth weight percentage
- Nutritional status and psychosocial development
- Life expectancy of children at birth
- IMR
- Child mortality rate (1–4 years)
- Maternal mortality rate
- Disease specific mortality rate
- Morbidity—incidence; prevalence
- Disability prevalence.
- Millennium development goal indicators:Health-related millennium development goals and indicators
Goal 1: Eradicate extreme poverty and hunger
Indicator
- Prevention of underweight children under 5 years of age.
- Proportion of population below minimum level of dietary energy consumption.
Goal 4: Reduce child mortality
Indicator
- Under 5 mortality rate
- Infant mortality rate
- Proportion of 1-year-old children immunized against measles.
Goal 5: Improve maternal health
Indicator
- Maternal mortality rate
- Proportion of births attended by skilled health personnel
Goal 6: Combat HIV/AIDS, malaria and other diseases
Indicator
- HIV prevention among young people 15 to 24 years
- Condom use rate
- No. of children orphaned by HIV/AIDS
- Prevalence and death rates associated with malaria
- Proportion of population in malaria risk areas using effective malaria prevention and treatment measures
- Prevention and death rates associated with TB
- Proportion of TB cases detected and cured under DOTS.
Goal 7: Ensure environmental sustainability
Indicator
- Proportion of population using solid fuel
- Proportion of population with sustainable access to an improved water source, urban and rural
- Proportion of urban population with access to improved sanitation.
Goal 8: Develop a global partnership for development
Indicator
- Proportion of population with access to affordable essential drugs on a sustainable basis.
Levels of Health Care
Health services organized at three levels:
- Primary health care:
- First level of contact of individual and health system.
- Essential health care (primary health care) is provided at the primary health centers and subcenters.
- Common health problems are managed.
- Secondary health care:
- First referral level.
- More complex problems are managed, mainly curative services.
- District hospitals and community health centers provide these services.
- Tertiary health care:
- Superspecialist care provided.
- Regional and central level institutions, medical college hospitals provide such care.
Health Team
Group of persons who share common health goal and common objectives, determined by community needs and toward the achievement of which each member of the team contributes in 14accordance with his competence and skills and respecting the functions of the other.
Types: Hospital team or community health work team.
Members: Doctors, nurses, social workers, health assistants, health worker female, health worker male, trained dais, village health guides.
Leader: The team must have a leader who will plan, monitor and evaluate the health services.
Services: Depending on the community needs.
- HFA (refer later)
- Primary health care (refer later).
Spectrum of Health
Health and disease lie along a continuum, lowest is death, highest is WHO's positive health.
Determinants of Health (Flow chart 1.1)
- Biological determinants (heredity): Genetic constitution determines disease, e.g. chromosomal anomalies, mental retardation, errors of metabolism, diabetes. Prevention by genetic screening and gene therapy.
- Behavioral: Lifestyle—The way people live, e.g. smoking, drinking, drugs, diseases, e.g. coronary heart disease, hypertension, obesity, lung cancer, illnesses associated with lack of sanitation, poor nutrition, poor personal hygiene, customs, cultural patterns.
- Environment: Hippocrates was 1st to relate disease to environment, e.g. climate, water air.
- Internal environment: Harmonious functioning of every tissue, organ, organ system.
- External environment or macroenvironment, all that is external to the human host—physical, biological, psychosocial.
- Microenvironment: The individuals' way of living and lifestyle, e.g. eating habits, personal habits (smoking, drinking, drugs).
- Occupational environment: Environment at work.
- Socioeconomic environment: Education, occupation, income, social group for interaction.
- Moral environment.
- Socioeconomic conditions: Socioeconomic development, e.g. per capita GNP, education, occupation, nutrition, housing, political system affect health.
- Economic progress leads to increased purchasing capacity, standard of living, quality of life, small family norm, pattern of disease, health seeking behavior.
- Illiteracy associated with poverty, malnutrition, ill health, high infant and child mortality rates.
- Education: Compensates the effect of poverty, e.g. Kerala state female literacy 87.8 percent compared to 54.2 percent for all India.
- Occupation: Employment promotes health because it gives income and status.
- Political system: Resource allocation for health, WHO expects 5 percent of GNP for health whereas India spends 3 percent on health.
- Sociocultural: From birth to death sociocultural factors, e.g. infant and child feeding, nutrition, exercise, diet pattern, customs, habits, e.g. open defecation, spitting everywhere.
- Health services: Family welfare services—Mother and child immunization, provision of safe water, sanitation, primary health care, equitably distributed, accessible, at a cost the community and country can afford.
- Aging of the population: Seven percent of population in India >60 years—Geriatric problems.
- Gender: Lesser child—Female child.Women—Nutrition, reproductive health, violence, lifestyle-related conditions, occupational environment.
- Science and technology: Food production, green revolution, white revolution, better treatment facilities.
- Information and communication: Easy access to information on Internet.
- Equity and social justice: Health care for all irrespective of capacity to pay.
- Human rights: Everyone has the right to a standard of living adequate for the health and well-being of himself and his family.
Interaction of Agent, Host, Environment
Web of causation considers all the predisposing factors and their complex inter-relationship with each other. It is a model which shows a variety of possible interventions that could be implemented to reduce, e.g. myocardial infarction.17
Agent factors | Host factors | Environmental factors |
|---|---|---|
1. Biological agents—Viruses, bacteria, fungi, protozoa, rickettsiae | 1. Demographic characteristics age, sex, ethnicity | 1. Physical environment—Air, water, soil, housing, climate, heat, cold, light, noise, radiation |
2. Nutrient agents—Proteins, fats, carbohydrates, vitamins, minerals, water. Malnutrition causes PEM, anemia, Vitamin A deficiency, goiter, obesity | 2. Biological characteristics genetic factors, biochemical levels of blood, e.g. cholesterol blood groups, immunological factors, physiologic functions—BP, PEFR | 2. Biological environment viruses, bacteria, fungi, vectors, rodents 3. Psychosocial environment, man and interaction with his social group social factors—Poverty, urbanization, migration, exposure to stress |
3. Physical agents—Heat, cold, humidity, pressure, radiation, electricity, sound | 3. Social and economic characteristics socioeconomic status, education, occupation, housing, marital status | |
4. Chemical agents Endogenous—Bilirubin, urea, ketones, uric acid, calcium carbonate. Exogenous—Allergens, fumes, dust, insecticides, gases | 4. Lifestyle factors—smoking, alcohol, drugs, nutrition, physical exercise | |
5. Mechanical agents—Friction may lead to sprains, dislocation, death | ||
6. Absence, insufficiency, excess of a factor. Chromosomal—Mongolism, congenital heart disease, nutrients factors | ||
7. Social agents—Poverty, smoking, drug abuse |
Responsibility for Health
Individual responsibility | Community responsibility | State responsibility | International responsibility |
|---|---|---|---|
Individual has to take responsibility for his own health. Self-care—diet, exercise, weight, sleep, smoking, alcohol, drugs, personal hygiene, yearly screening above 35 years, immunization, disease prevention measures, reporting early when sick and accepting treatment, family planning, recording own BP, sugar | Primary health care, community participation, health care of the people by the people for the people. Community can: (i) Provide facilities, manpower, logistic support, funds (ii) Be actively involved in planning, management and evaluation (iii) Use the health service. | Health is a state responsibility. The state shall regard the raising of the level of nutrition and standard of living of its people and improvement of public health as among its primary duties—primary health care approach. | WHO helps nations to strengthen their health system to combat diseases, e.g. Eradication of smallpox, health for all, campaign against smoking, AIDS. |
It does not mean that all the causes need to be removed to prevent the disease. Sometimes just one significant factor if removed can control the disease, e.g. smoking.
CONCEPT OF DISEASE
Definition
Disease—dis-ease, without ease; deviation from complete physical and mental well-being.
Concept of Causation
Germ theory of disease:
Disease agent → Man → Disease.
One-to-one relationship between causal agent and disease. It is known now that disease is rarely caused by a single agent alone.
Epidemiological Triad (Fig. 1.1)
Web of causation (Flow chart 1.2)
Risk Factors
Diseases | Risk factors |
|---|---|
Heart disease | Smoking, high BP, hypercholesterolemia, diabetes, obesity, lack of exercise, Type A personality |
Cancer | Smoking, alcohol, solar radiation, ionizing radiation, occupational cancers, environmental pollution, medicines, infectious agents, dietary factors |
Stroke | Smoking, high BP, hypercholesterolemia |
Motor vehicle accident | Alcohol, nonuse of helmets and seat belts, speed, automobile design, roadway design |
Diabetes | Obesity, diet |
Cirrhosis of liver | Alcohol |
Definition
Risk factor may be:
- Truly causative, e.g. smoking for lung cancer
- Contributory to the undesired outcome, e.g. lack of physical exercise for coronary heart disease
- Predictive only in statistical sense, e.g. illiteracy for perinatal mortality.
Some risk factors are modifiable, others not modifiable, e.g. smoking, high BP, hypercholesterolemia, diabetes, obesity are modifiable whereas age, sex, race, family history are not modifiable.
Risk factors may characterize as:
Individual: Age, sex, smoking, hypertension.
Family: Education, occupation, income.
Community: Malaria, TB, poor sanitation.
Methods to Identify Risk Factors
Epidemiological studies: Case control and cohort studies.
Prevention and Control of Risk Factors
Primordial and primary prevention important, e.g. health education in school health program.
Natural History of Disease
Way in which a disease evolves over time from earliest prepathogenesis phase to its termination as recovery, disability or death in the absence of treatment or prevention. Each disease has its own natural history.
Method of Study
Cohort study is the best method of study but it is costly, also problem of attrition.
Therefore cross-sectional or case control studies help to find out about natural history of diseases.22
Natural History of Disease
Prepathogenesis phase | Pathogenesis phase |
|---|---|
The period prior to onset of disease in man | Begins with entry of disease agent in the susceptible host |
“Man in the midst of disease” Epidemiological triad-agent host and environmental interaction results in disease | → Disease agent multiplies → Tiss and physiology changes → Incubation period, early and late pathogenesis → Recovery, disability or death This phase may be modified by intervention, e.g. immunization, chemotherapy |
Iceberg of Disease (Fig. 1.2)
Disease in the community can be compared with an iceberg.
Floating tip represents what the physician sees—clinical cases.
Majority the submerged portion represents hidden mass of disease, e.g. latent, inapparent, presymptomatic, undiagnosed cases, carriers in the community, e.g. malnutrition, polio, hypertension, diabetes mellitus, anemia, mental illness.23
Hidden part is undiagnosed, reservoir of disease and its detection and control is a challenge to modern techniques in preventive medicine.
Risk Groups
- Biological situation
- Age group: Infants, toddlers, elderly
- Sex: Females in reproductive age
- Physiological state: Pregnancy, cholesterol level, high BP
- Genetic factors: Family history of genetic disorders.
- Physical situation
- Rural, urban slums
- Living conditions, overcrowding
- Environment: Water supply, proximity to industries.
- Sociocultural and cultural situation
- Social class
- Ethnic and cultural group
- Family disruption, education, housing
- Customs, habits, behavior (smoking, overeating, lack of exercise, drug addiction)
Concepts of Control
Disease control | Disease elimination | Disease eradication |
|---|---|---|
Definition: The disease agent is permitted to persist in the community at a level it ceases to be a public health problem, e.g. malaria control Activities aimed at reducing the incidence of disease, duration of disease, effects of infection both physical and psychosocial complications and financial burden to community control activities may incorporate primary prevention, secondary prevention or both | An intermediate goal between control and eradication Interruption of transmission of disease, e.g. measles, polio, diphtheria | To tear out by roots Termination of all transmission of infection by extermination of infectious agent, e.g. smallpox |
- Lifestyles and attitudes
- Access to health services.
Identification of risk groups, e.g. at risk mothers, at risk infants, at risk families, chronically ill, handicapped, elderly in the population known as risk approach.
It is a managerial device for increasing efficiency of health services within the resources.
It is summed up as something for all but more for those in need.
Spectrum of Disease
Spectrum of disease varies from subclinical infections to fatal illnesses.
The different clinical manifestations are reflections of the individuals' different states of immunity.
For example: Leprosy, can be modified by interventions— early diagnosis and treatment.
Functions of Physician
Physician: A physician is a person who having been regularly admitted to a medical school duly recognized in the country in which it is located, has successfully completed the prescribed courses of studies in medicine and has acquired the requisite qualification to be legally licensed to practice medicine (comprising prevention, diagnosis, treatment and rehabilitation) using independent judgment to promote community and individual health.26
Functions
- The care of the individual: To make a diagnosis and treat individuals regarding illness, nutritional problems and emergency care.
- The care of the community: Physician is the leader of the health team and renders primary health care to the community comprising the 8 essential elements.
- The physician as a teacher:
- “Doctor” means to teach.
- Physician has a major responsibility as a teacher and health educator.
Community Diagnosis
Definition: Pattern of disease in a community and factors influencing them.
It is based on collection of data pertaining to age and sex distribution of population, socioeconomic status, vital statistics, e.g. birth rate, death rate, incidence and prevalence of important diseases in the area.
Mainly assessing the health needs and health problems of the community.
The felt needs should be next investigated and listed according to priority for community treatment.
Community Treatment
Based on community diagnosis, community treatment is undertaken to meet the health needs.
Community Health Interventions
For example, improvement of water supply, immunization, health education, control of specific diseases, health legislation.
Characteristics of Community Action
- It must effectively utilize the available resources
- There should be intersectoral coordination
- There should be community participation in the planning, monitoring, evaluation of the program.
Concepts of Prevention
Levels of prevention | Modes of intervention |
|---|---|
Primordial prevention: Prevention of the emergence or development of risk factors in countries or population groups in which they have not yet appeared | Through individual and mass health education, e.g. during school health program to promote healthy lifestyle, e.g. diet, physical exercise, not picking up habits of smoking, alcohol, drugs |
Primary prevention: Action taken prior to the onset of disease which removes the possibility that a disease will ever occur Each individual should take responsibility for his health, his family's health and community health Strategies:
| (a) Health promotion
|
(b) Specific protection immunization, nutritional supplement, chemoprophylaxis, e.g. malaria, immunoprophylaxis, protective device in industry, protective device for traffic accident, e.g. helmets, safety belt, protection from carcinogens, protection from allergens | |
Secondary prevention: Action which halts the progress of a disease at its incipient stage and prevents complications | Early diagnosis and treatment, e.g. diabetes mellitus, hypertension, cervix cancer, breast cancer, TB, leprosy, malaria |
Tertiary prevention: Intervention in the late pathogenesis phase—All measures to reduce impairments and disabilities, minimize suffering caused by existing departures from good health and promote the patients adjustment to irremediable conditions. | (a) Disability limitation impairment: Any loss or abnormality of psychological, physiological or anatomical structure or function, e.g. mental retardation, defective vision, loss of foot Disability—Lack of ability to perform an activity in the manner or within the range considered normal for a human being handicapa disadvantage for an individual resulting from an impairment or disability that limits the fulfillment of a role that is normal, e.g. Disease → impairment → disability → handicap accident → loss of foot → can not walk → unemployment |
(b) Rehabilitation: 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. Medical rehabilitation—Restoration of function, e.g. reconstructive surgery of hand after accident or leprosy. Social rehabilitation—Restoration of family and social relationship. Economic rehabilitation—Financial assistance to recover from handicap, e.g. loan under self- employment scheme. Vocational rehabilitation—Restoration of capacity to earn a livelihood. Psychological rehabilitation—restoration of personal dignity and confidence. | |