Individuals with health problems go to their doctor, are diagnosed and prescribed treatment. Public-health doctors, however, use epidemiological studies (see EPIDEMIOLOGY, and below) to diagnose the causes of health problems in populations and to plan services to treat the health and disease problems identified. Public-health practitioners are concerned not just with individuals, but also with whole populations, especially those who are disadvantaged in some way. They have to take into account that the health of populations is also dependent on factors such as the social, economic and physical environment in which people live and the nutrition and health care available to them.
Different legal frameworks exist in different countries, depending on their social and political development. All are concerned to stop the spread of infectious diseases, and to maintain the safety of food and water supplies and waste disposal. Most are also associated with housing standards, some form of poverty relief, and basic health care. Some trading standards are often covered, at least in relation to the sale and distribution of poisons and drugs, and to controls on industrial and transport safety – for example, in relation to drinking and driving and car design. Although these varied functions protect the public health and were often originally developed to improve it, most are managerially and professionally separate from today's public-health departments. So public-health professionals in the NHS, armed with evidence of the cause of a disease problem, must frequently act as advocates for health across many agencies where they play no formal management part. They must also seek to build alliances and add a health perspective to the policies of other services wherever possible.
is the principal diagnostic method of public health. It is the study of the distribution of and what determines health-related states in specified populations, and the application of this study to the control of health problems. Public-health practitioners also draw on skills such as those of statisticians, sociologists, anthropologists, economists and policy analysts in identifying and trying to resolve the health problems of the societies they serve. Treatments proposed are likely to extend well beyond the clinic or hospital and may include recommendations for measures to resolve poverty, improve sanitation or housing, control pollution, change lifestyles such as smoking, improve nutrition, or change health services. At times of acute EPIDEMIC, public-health doctors have considerable legal powers to enable them to prevent infection from spreading. At other times their work may be more concerned with monitoring, reporting, planning and managing services, and advocating policy changes to politicians so that health is promoted.
The term ‘the public health’ can relate to the state of health of the population, and be represented by measures such as MORTALITY indices (e.g. perinatal or infant mortality and standardised mortality rates), life expectancy, or measures of MORBIDITY (illness). These can be compared across areas and even countries. Sometimes people refer to a public health-care system; this is a publicly funded service, the primary aim of which is to improve health by the use of population-based measures. They may include or be separate from private health-care services for which individuals pay. The structure of these systems varies from country to country, reflecting different social composition and political priorities. There are, however, some general elements that can be identified:
The collection, collation and analysis of data to provide useful information about the distribution and causes of health and disease and related factors in populations.
The design, advocacy and implementation of policies to improve health. This may be through the provision of PREVENTIVE MEDICINE, environmental measures, influencing the behaviour of individuals, or the provision of appropriate services to limit disability and handicap. It will lead to advocacy for health, promoting change in many areas of policy including, for example, taxation and improved housing and employment opportunities.
Assessment of the first two steps to assess their impact in terms of effectiveness, efficiency, acceptability, accessibility, value for money or other indicators of quality. This enables the programme to be reviewed and changed as necessary.
So far as the UK is concerned, foundations of a public-health system were created in the 19th century in response to rapid enlargement of towns. The ‘sanitary’ concept was fundamental to these developments. This suggested that overcrowding in unsanitary conditions was the cause of most disease epidemics and that improved sewerage and clean water supplies would prevent them. Successive public-health laws were passed by Parliament, initially about sanitation and housing, and then, as scientific knowledge grew, about bacterial infections.
In the middle of the 19th century the first medical officers of health were appointed with responsibility to report regularly and advise local government about the measures needed to control disease and improve health. After more than a century they changed as part of the reforms of the NHS and local government in the 1960s and became more narrowly focused on the health-care system and its management. Increased recognition of the multi-factorial causes, costs and limitations of treatment of conditions such as CANCER and heart disease, and the emergence of new problems such as AIDS/HIV and BOVINE SPONGIFORM ENCEPHALOPATHY (BSE) have proved the importance of prevention and a broader approach to health. With it has come recognition that, while disease may be the justification for action, a narrow disease-treatment-based approach is not always the most effective or economic solution. The role of the Director of Public Health (the successor to the Medical Officer of Health) is again being expanded. (See also ENVIRONMENTAL MEDICINE.)
Initially, public-health practice related to food, the urban environment and the control of infectious diseases. Early examples include rules in the Bible about avoiding certain foods. These were probably based on practical experience, had gradually been adopted as sensible behaviour, become part of culture and finally been incorporated into religious laws. Other examples are the regulations about quarantine for PLAGUE and LEPROSY in the Middle Ages, vaccination against SMALLPOX introduced by Edward Jenner, and Lind's use of citrus fruits to prevent SCURVY at sea in the 18th century.
It was during the 19th century, in response to the health problems arising from the rapid growth of urban life, that the foundations of a public-health system were created. The ‘sanitary’ concept was fundamental to these developments. This suggested that overcrowding in unsanitary conditions was the cause of most disease epidemics and that improved sanitation measures such as sewerage and clean water supplies would prevent them. Action to introduce such measures was often initiated only after epidemics spread out of the slums and into wealthier and more powerful families. Other problems such as the stench of the River Thames outside the Houses of Parliament also led to a demand for effective sanitary control measures. Successive public-health laws were passed by Parliament, initially about sanitation and housing, and then, as scientific knowledge grew, about bacterial infections.
In the middle of the 19th century the first medical officers of health were appointed with responsibility to report regularly and advise local government about the measures needed to control disease and improve health. Their scope and responsibility widened as society changed and took on a wider welfare role. After more than a century they changed as part of the reforms of the NHS and local government in the 1960s and became more narrowly focused within the health-care system and its management. Increased recognition of the multi-factorial causes, costs and limitations of treatment of conditions such as cancer and heart disease, and the emergence of new problems such as AIDS/HIV and BOVINE SPONGIFORM ENCEPHALOPATHY (BSE) have again showed the importance of prevention and a broader approach to health. (See also ENVIRONMENT AND HEALTH.)