Lecture 1 The public health and public health

Lecture 1 The public health and public health systems as a science and subject Maksimenko Lyudmila Leonidovna

The public health and public health systems is a science studying: • The health of a population, • its forming factors and conditions, • and creating the treatment and prophylactics methods aimed at public health improvement

Basic historical events in the development of Public health and Public health systems The history of occurrence of our science is closely connected with the need of doctors to explain the reasons of health and illnesses of their patients and also to learn to control their health. From time immemorial man has been interested in trying to control disease. It is possible to give many examples from history of medicine confirming that many doctors connected occurrence of diseases with adverse conditions of a life of their patients.

Basic historical events in the development of Public health and Public health systems Among many names in Hindu medicine, that of Susruta, the “Father of Indian surgery” stands out in prominence. He compiled the surgical knowledge of his time in his classic “Susruta Samhita” (it was compiled between 800 BC and 400 AD). Though this work is mainly devoted to surgery, it also includes medicine, pathology, anatomy, midwifery, ophthalmology, hygiene and bedside manners. Susruta taught attentive supervision over the patient: how he behaves, how he eats, how has a rest, how answers questions; that is what is the character of his behavior and the vital circumstances which have led to illness. For treatment Susruta recommended different diets, physical exercises, conditions change.

Great Hippocrates (460 -370 BC) who is often called the “Father of Medicine” "The majority of illnesses depend on acts, thoughts of the person and his life conditions. " He studied such things as climate, water, clothing, diet, habits of eating and drinking and the effect they had in producing disease. His book “Airs, Water and Places” is considered a treatise on social medicine and hygiene. The Hippocratic concept of health and disease stressed the relation between man and his environment.

Abu Ali Ibn-Sina (980 -1037) The great doctor of medieval East Abu Ali Ibn-Sina known to the western world as Avicenna named three important conditions for health preservation: • moderate physical exercises, • a rational diet • and sleep.

Bernardino Ramatstsini (1633 – 1714) Italian doctor Bernardino Ramatstsini has proved for the first time that not only conditions of life and behavior of a person, but also working conditions can cause illness. Its scientific work "Reasoning's on illnesses of handicraftsmen" contains the description of 60 occupational diseases with specifying of their reasons, preventive and treatment measures.

Many Russian doctors also considered, that "it is necessary to treat not illness, but a patient", that is a person taking into account individual character, temperament, life and work conditions. At the end of the 18 th century many of the professors of the Moscow University stressed the necessity of public health study and introduction of a new subject at medical faculties. But the lecture course on public health has been introduced only in the second half of the 19 th century, and only at several medical faculties and occasionally.

Formation of a new science studying public health has occurred at the very beginning of the 20 th century in Germany. Interest to public health in Germany has been caused by adoption of the law of social insurance providing three sources of payment for medical aid: means of the state budget, businessmen’s profit, and workers’ inpayments. Under new conditions, businessmen became interested in studying health state of workers, morbidity decrease, carrying out of preventive measures. A German doctor Alfred Grotjan became a founder of social hygiene (the original name of a science studying public health state).

In 1903 Alfred Grotjan began publishing a magazine on social hygiene, and in 1905 he founded a scientific organization on social hygiene and medical statistics in Berlin. In 1920 Alfred Grotjan became successful in establishment of the Chair of Social Hygiene at Medical Faculty of the Berlin University. At the same time Renе Zand founded the Belgian Social and Medical Association, and at his initiative the similar chairs have been opened at other universities of Europe. In 1922 the first chair of social hygiene was set up at the Moscow University, and in succeeding years all medical higher schools in our country have opened such chairs.

In the thirtieth years of the last century in other countries of the world the chairs studying public health have opened. Social hygiene is a young science; it still continues to be formed and consequently has no common unitized name as a teaching subject. In many countries this subject is called social medicine, medical sociology, preventive and social medicine, sociology of public health services (USA), public health. In the resent years in Russian medical higher schools this subject got the name "Public health and public health systems. " But however this subject was called, it is taught in all medical higher schools and studies, first of all, condition of public health and factors forming it.

А definition of "health" In the modern literature there is a considerable quantity of definitions of "health, " however the basic one, adopted in all countries, is a definition of the World Health Organization (WHO). In the WHO Charter accepted in 1948 it is written: "Health is a condition of full physical, spiritual and social well-being, and not just absence of illnesses and physical defects. "

In medico social researches, at health estimation, it is accepted to point out four levels: 1. Health of a separate person – individual health; 2. Health of social and ethnic groups – group health; 3. Health of the population of administrative territory – regional health; 4. Health of population, a society as a whole – public health. Unlike the majority of medical and clinical disciplines dealing with a separate person, an individual and his health, public health and public health systems studies a state of health of all population of the country.

For a quantitative estimation of group, regional and public health it is customary to use the following indices: 1. Demographic indices (death rate, birth rate, average life expectancy). 2. Morbidity rate. 3. Disability rate. 4. Indicators of physical development of the population. The greater part of these indicators is of negative character; it concentrates doctors’ attention to pathological conditions and health definition through morbidity intensity.

However, in the majority of countries of the world the main function of public health services system at present is prevention of diseases and health preservation of healthy people; that is why it is very important to use the indicators positively estimating health. They are: 1. A health index – a share of practically healthy population, which did not appeal for medical aid on account of diseases within a year; 2. Average duration of healthy life and others.

At a complex estimation of health of separate patients and population health as a whole the following five groups of health are distinguished: 1 st group – practically healthy people – the persons who do not have chronic diseases and functional deviations, seldom and short being ill with acute diseases; 2 nd group – risk group – persons who do not have chronic diseases, but have functional deviations in activity of various organs and systems, and also persons being frequently and prolonged ill with acute diseases; 3 rd group – chronic patients with a compensated form of disease and preserved functional abilities of the body; 4 th group – chronic patients with a sub compensated form of disease and with reduced functionality of the organism; 5 th group – chronic patients with a decompensate form of disease and invalids.

In public health study the following classification of factors that define it is applied: • Social and economic factors (material well-being, living conditions, working conditions, food quality, mutual relations in a family and others); • Biological factors (sex, age, heredity, temperament etc. ); • Ecological, natural and climatic factors (climate, weather, air condition, water, soil, level of solar radiation, etc. ); • Medical and organizational factors (availability and quality of a medical and social help). Conditions of a personal and collective life can be united and form a concept – a way of life.

A way of life means the most important features of the life and behaviour of people in a definite social environment, society. The way of life includes • The activity directed on set of features health preservation and prevention of diseases, can characterizing • activity of people at a factory and in a household, • political, cultural, physical, educational activity, • medical activity and others. form a healthy way of life • A healthy way of life is favorable conditions of vital activity of a person, high level of culture and hygienic habits, allowing to keep health, to prevent from development of diseases.

Features of Russians’ life-style • Regularly go in for physical training - 12 % of Russians • Abuse spirits – more than 30 million persons (21 %) • Regularly take drugs –nearly 2 million people • Smokers - 45 % of the population Formation of a healthy way of life in these conditions is the basic means of primary preventive maintenance and should become the basic purpose of social policy and major duty of all medical workers.

The influence of separate factors on public health • Nature-climatic factors. The sharp change of atmospheric processes leads to morbidity growth. So, for example, fluctuations of atmospheric pressure negatively influence cardiovascular system, and temperature drops lead to increase of respiratory diseases. . Shortage in water and soil of some microelements (iodine, fluorine and others) leads to occurrence of diseases endemic for this district.

Environmental contamination causes increase in level of morbidity and death rate of the population. So, in cities with well developed industry high concentration of harmful substances in air, water and soil leads to increase of prevalence of illnesses of respiratory system, kidneys and oncological diseases. Emissions of harmful substances into atmospheric air (thousand tons)

Influence of biological factors on health of the person is easy for tracking at studying of morbidity level in children of a different sex. Morbidity level in children during the first three years of life is highest, and then morbidity decreases. Morbidity level of boys during the first six years of life is essentially above the morbidity level of their contemporary-girls, at age of six years morbidity levels are leveled, and further morbidity of girls is always higher, than at boys. Children morbidity level depending on age and sex (‰) girls boys

Influence of biological factors on health of the person • Infectious diseases at children happen much more often, than at adults, but with age increase prevalence of illnesses of blood circulation system and death rate from them grow. • Indices of morbidity and death rate from malignant growths increase with age, but at women they are considerably lower, than at men.

A parity of social and biological features The person, entering into this world, receives health as gift of the nature, which he has inherited from ancestors. However the biological origin is never shown in the person in purely natural form. The man is a unique phenomenon of a society and the nature, representing a social and biological alloy. A problem of a parity of social and biological features in the person is a key to understanding of the nature and character of health of the person, its illnesses which needs to be considered as biosocial categories.

In documents of the WHO it was repeatedly specified, that, first of all, health of people is a social category, so for public health estimation the WHO recommends following indices: • Payment of a total national product to public health services. • Availability of the primary medico-social help. • Coverage of the population with medical aid. • Level of immunization of the population. • Degree of survey of pregnant women by qualified personnel. • Condition of children’s diet. • Level of children's death rate. • Average duration of a forthcoming life. • Hygienic literacy of the population.

Dependence between income average level per capita and life expectancy Countries Bangladesh India Algeria Mexico The Netherlands The USA Compare the Average life income per capita expectancy in US dollars (years) 92 46 133 52 780 59 996 65 5568 74 7034 76 • Social conditionality of health proves to be true by numerous medico-social researches. So, for example, while studying dependence between income average level per capita and average life expectancy worldwide it is easy to notice, that with income increase per capita average life expectancy increases also.

Death rate of the population of the USA depending on the marital status (%) Age in years, sex Unmarried persons Married The dissolved male female 3, 4 2, 0 1, 5 0, 9 5, 3 2, 2 Male female 15, 7 6, 4 8, 4 4, 5 25, 9 7, 2 25 -34 45 -54 60 -64 male female 38, 0 25, 3 57, 0 14, 6 13, 1 17, 3 • The American scientists have determined that the state of health in many respects depends on the marital status. Both at married men and women a death rate is essentially lower, than at unmarried and especially dissolved

The force of complex influence the main of factors on public health The factors defining health of the population, co-operate with each other, have regional features, and vary in time. At complex medico-social research the most possible number of factors is taken into consideration, their interrelation and force of influence of each of them. Scientists of our country managed to calculate, that such major index of health as morbidity is caused to 50 % by conditions and a way of life, to 20 -25 % by condition (pollution) of an environment, to 20 % by genetic factors and to 10 -15 % by public health services condition. For other indices of health above resulted rates can be others; however the leading part of conditions and a way of life remains invariable.

Share of separate risk factors in formation of health of the population

Rick factors The population state of health depends on influence of various external and internal factors. The factors which are potentially hazardous to health of a person, promoting occurrence of diseases, are called risk factors. A task of the state and public health services system is to decrease intensity of risk factors influence and to strengthen the factors positively influencing on health. The concept that disease is due to multiply factors is not a new one. It is known that diseases such as coronary heart disease and cancer are due to multiple factors. For example, excess of fat intake, smoking, lack of physical exercise and obesity are all involved in the pathogenesis of coronary heart disease. Most of these factors are linked to lifestyle and human behavior.

Rick factors For many diseases, the disease “agent” is still unidentified, e. g. coronary heart disease, cancer, peptic ulcer, mental illness, etc. Where the diseases agent is not firmly established, the aetiology is generally discussed in terms of “risk factors”. The term “risk factors” is used by different authors with at least 2 meanings: • an attribute or exposure that is significantly associated with the development of a disease, • a determinant that can be modified by intervention, thereby reducing the possibility of occurrence of disease or other specified outcomes.

• Rick factors are often suggestive, but absolute proof of cause and effect between a risk factor and disease is usually lacking. That is, the presence of a risk factor does not imply that the disease will occur, and in its absence, the disease will not occur. The important thing about risk factors is that they are observable or identifiable prior to the event they predict. It is also recognized that combination of risk factors in the same individual may by purely additive or synergistic (multiplicative). For example, smoking and occupational exposure (shoe, leather, rubber, dye and chemical industries) were found to have an additive effect as risk factors for bladder cancer. On the other hand, smoking found to be synergistic with other risk factors such as hypotension and high blood cholesterol. That is, the effects are more than additive. • Risk factors may be truly causative (e. g. , smoking for lung cancer); they may be merely contributory to the undesired outcome (e. g. , lack of physical exercise is a risk factor for coronary heart disease), or they may be predictive only in a statistical sense (e. g. , illiteracy for perinatal mortality).

Modifiable and unmodifiable risk factors • Some risk factors can be modified; others cannot be modified. The modifiable factors include smoking, physical activity, diet. They are amenable to intervention and are useful in the care of the individual. The unmodifiable or immutable risk factors such as age, sex, race, family history and genetic factors are not subject to change. They act more as signals in alerting health professionals and other personnel to the possible outcome. • Risk factors may characterize the individual, the family, the group, the community or the environment. For example, some of the individual risk factors including age, sex, smoking, etc. But there also collective community risks – for example, from the presence of malaria, from substandard housing or a poor water supply or poor health care services. The degree of risk in these cases is indirectly an expression of need. Therefore it is stated that a risk factor is a proxy for need – indicating the need for promotive and preventive health services.

The detection of risk factors are a prelude to prevention. • Epidemiological methods (e. g. , case control and cohort studies) are needed to identify risk factors and estimate the degree of risk. These studies are carried out in population groups among whom certain diseases occur much more frequently than other groups. By such comparative studies, epidemiologists have been able to identify smoking as a risk for lung cancer; high serum cholesterol and high blood pressure as risk factors for coronary disease. The detection of risk factors should be considered a prelude to prevention. For each risk factor ascertained, the question has to be asked whether it can be reduced in a costeffective way and whether its reduction will prevent or delay the unwanted outcome. Since the detection procedure usually involves whole population, it bears some similarity to presymptomatic screening for disease.

Risk groups • Another approach developed and promoted by WHO is to identify precisely the “risk groups” (e. g. at-risk mothers, at-risk infants, at-risk families, chronically ill, elderly) in the population by certain defined criteria and direct appropriate action to them first. This is known as the “risk approach”. It has been summed up as “something for all, but more for those in need – in proportion to the need”. In essence, the risk approach is a managerial devise for increasing the efficiency of health care services within the limits of resources. WHO has been using the risk approach in MCH services for sometime.

Guidelines for defining “at-risk” groups 1. Biological situation: - Age group, e. g. , infants (low birth weight), elderly - Sex, e. g. , females in the reproductive age period - Physiological state, e. g. , pregnancy, high blood pressure - genetic factors, e. g. , family history of genetic disorders - other health conditions (disease, physical functioning, unhealthy behaviour) 2. Physical situation: - rural, urban slums - living conditions, overcrowding - environment: water supply, proximity to industries 3. Socio-cultural and cultural situation: - social class - ethnic and cultural group - family disruption, education, housing - customs, habits and behavior - access to health services - lifestyles and attitudes

Conclusion: Modern epidemiology is concerned with the identification of risk factors and highrisk groups in the population. Since resources are scarce, identification of those at risk is imperative. It helps to define priorities and points to those most in need of attention. The knowledge of risk factors and risk groups can be used to prevent disease in so far as we are able to remove or minimize the risk.