The scope, mission and method of contemporary public health
Professor Stephen Leeder, Menzies Centre for Health Policy, Victor Coppleson Building (D02), University of Sydney, New South Wales 2006. Fax: (02) 9351 5204; e-mail: firstname.lastname@example.org
A coherent public health response is critical to successfully addressing a wide range of issues facing society – from avian influenza through to climate change and obesity. Much can be learned from the long and varied history of public health. From the pioneering work of Ibn Sina to the ‘new public health’ and recent WHO commission on the social determinants of health, we see that public health has been constantly responsive to emerging concerns. It is also clear that it is not only ‘traditional’ notions of public health but action from diverse fields has helped to achieve the improvements in health that we now see. However, great inequality in health outcomes remain as we enter the 21st Century. Our challenge as the public health community is to engage diverse groups in advocating not just for health, but also for reductions in poverty and inequality.
Public health, which I take to encompass the efforts that society makes in an organised and institutionalised way to maintain health and prevent illness, requires allies from a broad range of disciplines to be effective. My passion is this: there is an urgent need for people in society, other than public health professionals, to take an interest, and become involved, in public health. We need to move public health from the margin to the mainstream of politics, social action, medicine and health policy.
Today, the scope of public health is vast, with traditional notions of quarantine still in vogue as we contemplate a response to the threat of avian influenza, while climate change is calling for new applications of public health in assessing the threats from migrating disease vectors and social dislocation due to drought and floods. We look to public health to help solve the big disparities in health between the Third World and the developed world, and between the haves and the have-nots in even the most affluent societies.
In addition to advances in what has been traditionally recognised as public health, there have also been great gains in health that have occurred because of advances in engineering, law, public administration, education, agriculture and commercial enterprise. These have not been efforts organised primarily to improve health and have not been the result of a deliberate public health effort. For example, in Poland after glasnost, in the mid-late 1980s, subsidies for meat and dairy products were abolished as part of economic restructuring. Imports of fresh fruit and vegetables rose as did consumption of vegetable oils. Heart disease deaths began to decline in two years.1
In this essay, I first touch lightly upon the origins of public health that illustrate its long history and its wide scope. These, together with the vast improvements that have occurred globally in health in recent decades, illustrate its mission. I conclude with some suggestions regarding what we might expect of public health in our contemporary world and the intellectual form that public health might take.
The origins of public health
Peter Watson, in his magisterial volume Ideas: a History from Fire to Freud,2 reminds us that public health is not an exclusive artefact of Western society. He finds evidence of hospitals and basic laws of public hygiene and containment of infections in Baghdad in the eighth century.
Ibn Sina, or Avicenna, an outstanding Persian physician who began medical practice around 997 AD, pioneered the study of the role of the environment in medicine (i.e. rudimentary epidemiology) in his Canon of Medicine. Beside his clinical work, he set out much of relevance to the practice of prevention and public health.
My health historian colleague Milton Lewis comments: “In the West, classic public health measures like urban public water and sewerage systems also unfolded: perhaps best known is imperial Rome, renowned for its aqueducts and sewers.
“However, there was no central idea of collective official action protecting the health of the whole population for the sake of health. Thus, clean abundant water was basically treated as an amenity. Graeco-Roman medicine promoted the notion of prevention but in the individual and only for those with means and time to pursue lifestyle advice. Only in early modern and modern Europe do we see evolving the idea of collective measures taken by government to protect the whole community, and for a very long time for utilitarian, not social equity, reasons – to keep trade flowing and with the rise of mercantilist (economic self-sufficiency) ideas from 17th century, to have a numerous and healthy national population as a military and economic resource. So from 14th century the Italian city-states instituted quarantine and isolation of plague cases in lazarettos; taken up in the northern European nation states like England later; and then the famous sanitary idea in England in 19th century.”
This is a view of the origins of modern Western public health shared by Watson and Michel Foucault (1973),3 who clearly point out that the current attachment of public health to notions of social equity has not always been a characteristic of the discipline. For example, as the Industrial Revolution took hold in Europe, living conditions in the big cities were appalling, especially for the poor workers. Their health became a matter of great concern to industrialists but only because they needed factory fodder.
So we have applied public health measures to the environment to assure clean drinking water, clean air, uncontaminated and nutritionally sound food, and to physical safety, and these efforts have been supplemented by massive advances in immunisation and the control of infectious diseases. But these actions have often not been done for socially worthy reasons (to improve the health of the public), but to create healthier workers for commercial purposes and fitter soldiers for militaristic reasons.
Epidemiology comes to the fore
The medical detective work of Dr John Snow, who tracked the source of a persistent cholera epidemic in London in 1854 to a water pump by the Thames, heralded the rise of numerical approaches to the measurement of health. Tracking the spread of infectious diseases and the process of enumerating deaths attributed to them became major drivers of civic quantification and census activity more generally, especially in Britain. Thus was born the discipline of epidemiology, which seeks through quantitative processes to measure the distribution of illness in society and, by careful analysis, the associations and correlations between personal and environmental factors that could account for the distribution of illness. The close association between health statistics and public health, obvious in Snow's work in London on cholera, has since been constant. Often, effective public health action has started with epidemiology.
Epidemiology is the numerical science that informs another vital aspect of public health, and that is the concept of risk and risk modification. When a risk factor is distributed in society, such as overweight is in ours, epidemiological calculations suggest that more will be gained by everyone losing half a kilogram than by 10% of the population losing five kilograms each. This puts public health in contrast with clinical medicine, which is concerned with the individual, how to reduce their risk and how to make them well again.
The tension between public health, with its concentration on achieving small changes in the risk profile of large numbers of people, and clinical medicine, with its concern for the few who are sick, is reflected in the way health dollars are allocated. Generally, the individual wins and public health loses – it is allocated about 2% of health spending in most Organisation for Economic Co-operation and Development (OECD) countries.
The evidence provided by epidemiology has been critical in public health and remains so today. Data transcend opinion, professional or popular, and present a solid base on which public health actions can be built. Data tell a story about the growing international problem of obesity, national successes in cancer screening and childhood immunisation programs, and regional failures in access to mental health services. Data highlight that Australia's high international ratings for longevity and infant mortality have not flowed through to our Indigenous people, and remind us of growing inequalities in health between our most and least advantaged citizens.4
However, we should note that many public health professionals and others have expressed frustration with the numbers game and have reacted negatively to epidemiology. A moment's reflection suggests that they have a strong argument. By no means all attributes relevant to health are capable of quantification.
This thinking about the determinants of health has led to the establishment of a powerful sub-branch of public health, labelled some 30 years ago as the ‘new public health’, which seeks to provide qualitative elucidation of why things are as they are, why some populations have high prevalence of elevated blood pressure or others have a striking proportion of centenarians.
The new public health makes considerable reference to sociological and anthropological insights and engages with the world of human behaviour and political activity, modified by an interest in ethics and human rights, in pursuit of better health. There is an interesting dialectic at work here – evidence-based advocates argue that rugged statistics are of most use to policy makers while the new public health people argue in favour of social adjustments, legislation and policy that reaches further back into society.
Two recent commissions reflect this diversity of approach to public health conceptualisation. In 2001, the World Health Organization (WHO) published a report of a commission, headed by poverty activist and economist Jeffrey Sachs, which was established to explore the interplay between macroeconomics and health.5 Three years later in 2004, the WHO went on to establish another commission, this time on the social determinants of health, headed by Michael Marmot.6
The future of public health
In looking to the future it helps to take account of our current position. Despite ongoing problems and suffering, there has been real progress. The health of all but the poorest developing nations has improved markedly over the past four decades. Infant mortality has been cut by half.7 Average life expectancy at birth worldwide was 65 years at the start of the new millennium, compared with 51 years in 1960.8 Women are experiencing increases in life expectancy that are larger than those enjoyed by men.9 Developing countries have increased food production well above population growth, with a 50% increase in per capita food availability.10 Fertility rates are falling.11
Simultaneously, the past decades have seen gains in relation to broader indicators of development in all but the very poorest African nations. Since 1975, literacy rates have increased substantially in all developing regions, particularly in Asia, the Pacific and Latin America, where rates are now around 90%. Rates in sub-Saharan Africa, Arab states and South Asia have also risen, from 35% in 1975 to around 60% in 2002.12 Primary school enrolment rates in low-income countries have increased from 65% in 1960 to 100% in 2000 (except for sub-Saharan Africa, where rates peaked at 80% in the 1980s).13 Economic gains are also substantial. Developing economies grew faster than high-income countries over the past decade (1995-2005) and faster than in the two previous decades.14 Extreme poverty in developing countries fell from 28% in 1990 to 19% in 2002.15
However, rising inequality (of income and opportunity) has occurred at the same time as these changes, and may be offsetting these gains. It has been suggested that the neo-liberalism of modern economic development has been key in increasing inequality,16–18 and Wilkinson19 has documented the steeper social gradient in health arising from widening income differentials.
Here in Australia we pride ourselves on being an egalitarian nation, where access to services such as health care, education, housing and clean water are seen as basic rights that governments are required to deliver universally. However, our overall good health is not shared by all and for too many Australians their health, their access to health care and their life expectancy are reduced to levels that are well below the average and the divide is growing. The most egregious example of this is the difference in health status and life expectancy between the general population and Indigenous people. But there is also a shocking complacency about our acceptance of the differences in health status and life expectancy between Australians who live in urban and rural areas. And why are we not troubled by the seven-year difference in life expectancy between men and women?
Internationally, public health still faces serious challenges from continuing infectious diseases. These include HIV, malaria and tuberculosis, especially in countries where poverty is rife such as sub-Saharan Africa and parts of Asia and the subcontinent. In Australia, we must tackle the eradication of Third-World diseases such as trachoma and high levels of otitis media and rheumatic fever in Indigenous communities and also prepare for the possibility of increasing rates of malaria, Nile River fever and Japanese encephalitis as a consequence of global warming.
However, diseases that relate to the way in which we live, increasing urbanisation and ageing have come to dominate the mortality charts and to account for a huge amount of misery. The WHO estimates that heart disease and stroke account for 10% and 5% of the global burden of disease, with a further 4% attributable to chronic respiratory diseases and 1% to diabetes.20 Cancer is close behind. Other chronic diseases make up a further 28% of the global burden of disease
Conventional wisdom in global public health has held that non-communicable diseases such as cardiovascular disease in the developing world are not significant problems. Yet cardiovascular disease already accounts for more deaths than communicable diseases and is poised to exact a huge economic toll in still-fragile emerging economies. The economic and social burden of non-communicable diseases will burgeon the longer the introduction of programs for prevention and early intervention is delayed.
Many of these disorders, such as diabetes and heart disease, occur because the risk factors that are associated with them – obesity, lack of exercise, elevated blood pressure and lipids, and smoking – derive from the way we organise our urban environments, the way we eat and especially the amount that we eat. If only these were conditions caused by an infectious agent, we would know how to deal with them! In relation to urbanisation, the design of new and regenerating cities should engage the interest of all – including public health professionals and concerned citizens. We are not really at the planning table and we should be.
Where to from here?
To meet the global health challenges today requires a form of public health that has both familiar and unfamiliar attributes. The infectious diseases, so tightly linked to poverty, call for the investment of global aid on a billion-dollar scale. As Jeffrey Sachs, advocate for the relief of poverty through health action puts it, it is hard to pull yourself up by your bootstraps if you have no boots.
In relation to the pandemics of obesity and other chronic illnesses, the international community has yet to determine the approach that it will take in regard to merciless advertising of unhealthy choices – for example, whether it will continue to tolerate the actions of the tobacco companies. One billion will die this century because of tobacco unless the sorts of strategies that have worked well to reduce smoking in Australia are internationalised. The Framework Convention on Tobacco Control – the world's first health treaty21– is good start; now it must be ratified and protocols developed to combat tobacco smuggling.
There are various approaches to development for health that we might take, including public policy strategies where government control is the dominant vector. However, a promising (if somewhat radical) approach is one in which agencies and interest groups in society, rather than governments, lead the way to necessary social change to achieve development goals.22 These civil society organisations may include patient groups, the private sector, medical associations, labour unions, and various lobbies. Their role is to put particular issues on the public agenda and to organise responses, working with governments and other agencies.
Some of my colleagues express concern about working with commercial and industrial interests that they see as the cause of contemporary public health problems. While I have no dispute that legislation and regulation are necessary elements of public health, and critical to our success in managing the pandemic of tobacco use that we have outsourced to the developing world, we need to be careful that we do not make extravagant claims about the evil empires of global commercial interests. The heyday of globalisation is not today. It was in 1914. The huge flows of labour that we saw then have not occurred today. Global trade is not anywhere near the levels it was at ahead of the outbreak of World War I.23 We have been there and done that. When it comes to matters of global nutrition, tactics developed in our battle against tobacco are not always useful, and we need to look to areas such as occupational health for clues as to how to combat the intertwined pandemics of cardiovascular disease, obesity and diabetes.
Among the many challenges that face us, issues of ecological and resource sustainability and the pressures of economic development look set to gain strength in the next 50 years. The upside of this will be a continued reduction in poverty and destitution. The downside is a raft of unsolved problems, including global warming, ocean acidification, depletion of clean water supplies, loss of species and the threat of new infectious diseases.
At the same time we face the necessity to act to combat the rising burden of non-communicable diseases, such as diabetes, respiratory and heart diseases, stroke, mental illness and cancer.
Fortunately, the things we need to do are largely known. They depend upon open access, social action, political commitment, leadership and patience. The challenge to all with an interest in public health is to make sure that history records that, having perceived this problem, our generation moved to deal with it. For that to occur, society – the public – needs to be more closely involved with the public health agenda and politically supportive of it. Our challenge as the public health community is to thus engage diverse groups in advocating not just for health, but also for reductions in poverty and inequality.