Chapter 6: Neglected Global Epidemics: three growing threats
Cardiovascular diseases: the need to act
Twenty-five years ago, when the delegates at the international Alma-Ata conference drew up a list of eight essential elements for primary health care, there was no mention of the treatment or prevention of conditions such as heart disease and stroke. The priority was to deliver adequate nutrition, safe water and basic sanitation, maternal and child health care, immunization against the major infectious diseases, the prevention and control of local endemic diseases, and the provision of essential drugs to the poorer countries of the world.
Cardiovascular diseases (CVDs) -- heart disease and stroke -- and other noncommunicable diseases were considered diseases of the industrialized countries -- so-called "Western diseases" -- brought about by ways of life utterly different from those in most of Africa, Asia and many other parts of the developing world. It is noteworthy, however, that as early as 1954 the delegate of India to the World Health Assembly called for steps to be taken towards the prevention of CVDs in developing countries.
The global health agenda is still dominated by the notion that communicable diseases need to be prevented and treated before CVDs receive attention. There is a lingering view that CVDs are mostly confined to wealthy people and are caused by natural ageing and degenerative processes. There persists a widespread belief that they are "lifestyle diseases", fully under the control of individual decisions.
The reality is quite different. CVDs have not only emerged in all but the very poorest countries, but are already well advanced; this growing burden has real potential to hinder social and economic development. Risk factors are indicators of future health status, and five of the top 10 risks worldwide are specific to noncommunicable diseases (1). These include raised blood pressure, tobacco use, alcohol consumption, cholesterol, and obesity or overweight. This is part of the well-documented epidemiological transition called the "double burden" that sees the arrival of the whole group of noncommunicable diseases with their shared risk factors on top of the persisting threat of communicable diseases. As a consequence, health systems are now required that can deal comprehensively with all common diseases, irrespective of their origin.
As highlighted in Chapter 1, in today's world most deaths are attributable to noncommunicable diseases (32 million) and just over half of these (16.7 million) are the result of CVD; more than one-third of these deaths occur in middle-aged adults. In developed countries, heart disease and stroke are the first and second leading causes of death for adult men and women. These facts are familiar and hardly surprising. What is surprising, however, is that in some developing countries, CVDs have also become the first and second leading causes, responsible for one-third of all deaths (see Figure 6.1).
Figure 6.1
In fact, twice as many deaths from CVD now occur in developing countries as in developed countries. Overall, in developing countries, CVD ranks third in disease burden (after injuries and neuropsychiatric disorders). Even in high-mortality developing countries, CVD is ranked very high.
A particular cause of concern is the relatively early age of CVD deaths in developing countries compared with those in the developed regions (2). One in two of the CVD-related deaths in India occur below the age of 70 years, compared with one in five in economically well-developed nations. In both rural and urban areas of the United Republic of Tanzania, stroke mortality rates are three times higher than those in England and Wales. What is not often recognized is that, globally, CVDs account for as many deaths in young and middle-aged adults as HIV/AIDS.
This does not mean that communicable diseases have quietly gone away, require less funding, or are now safely under control. The advent of HIV/AIDS shattered that hope (see Chapter 3). Malaria and tuberculosis are among other enormous threats that remain and are growing. In addition, as pointed out in Chapter 5, new infectious diseases have been emerging at the rate of one a year for the last 20 years or more: SARS is the latest. So it is legitimate that public health communities remain vigilant towards infectious diseases, and that this vigilance begins with primary health care, in accordance with the Declaration of Alma-Ata. However, the world cannot afford to lose sight of the growing social and economic threats posed by CVD and other noncommunicable diseases.
Ironically, CVDs are now in decline in the industrialized countries first associated with them. But from that irony stems hope: the decline is largely a result of the successes of primary prevention and, to a lesser extent, treatment. What has worked in the richer nations -- and especially for the most advantaged members of these societies -- can be just as effective in their poorer counterparts.
There is now abundant evidence to initiate effective actions at national and global levels to promote and protect cardiovascular health through population-based measures that focus on the main risk factors shared by all noncommunicable diseases. The population-wide application of existing knowledge has the potential to make a major, rapid and cost-effective contribution to their prevention and control and to benefit all segments of the population (3).
The main issue for policy-makers, at all levels of public health in developing countries, is how to deal with the growing burden of epidemics of noncommunicable diseases in the presence of persisting communicable disease epidemics. Furthermore, this challenge must be faced even where health system resources are already inadequate. Although considerable policy gains can be made very cheaply, especially intersectorally, extra provision must be found. This requires a greater share of national resources for health care, better use of existing resources, and new sources of funding. A special tax on tobacco products for disease prevention programmes is a readily available source of new funds for most countries.
The causes are known
The good news is that an impressive body of research has identified the causes of the CVD epidemics within populations (1). Global trade and marketing developments continue to drive the nutrition transition towards diets with a high proportion of saturated fat, sugar and salt. At the same time, protective elements like fibre and phytochemicals in fresh fruit and vegetables are being progressively depleted in diets. When combined with tobacco use and low levels of physical activity, this diet leads to population-wide atherosclerosis and the widespread distribution of CVDs. Variations in these same major risk factors explain much of the major difference in rates of CVDs between countries.
In summary, the major CVD risk factors of tobacco use, inappropriate diet and physical inactivity (primarily expressed through unfavourable lipid concentrations, high body-mass index, and raised blood pressure) explain at least 75--85% of new cases of coronary heart disease (4). In the absence of elevations of these risk factors, coronary heart disease is a rare cause of death. Unfortunately, the vast majority of the populations in almost all countries are at risk of developing CVD because of higher than optimal levels of the main risk factors. Only about 5% of adult men and women in wealthy countries are at low risk with optimal risk factor levels. There are only a few very poor countries in which these factors have not yet emerged as major public health problems.
Policies are available
One of the most exciting possibilities to emerge in public health in recent years is the integration of communicable disease and CVD prevention and control into comprehensive health systems led by primary care. Bringing this to fruition will mean reshaping the future of primary health care in response to a changing world. It would see all patients being offered -- across their lifespan -- prevention, treatment and long-term management of both sides of the double burden.
Achieving such integration will not be easy. Apart from other considerations, it will require cooperation between professional rivals, who each regard their side of the double burden to be more important than the other, and who compete for their share of limited resources. Such competitiveness has long been entrenched across the battlefields of public health. And yet, as the chapter of this report on SARS has shown, cross-disciplinary collaboration is not only possible but can be enormously rewarding to all concerned. In the case of this new epidemic, the world's best scientists, clinicians and public health experts were willing to set aside academic competition and work together for the public good -- because the circumstances so clearly required it. Paradoxically, a matching policy response to tackle public health challenges of even greater magnitude is lacking: the mounting menace of the global CVD epidemic is evolving rapidly.
Another critical policy issue, especially for poor countries, concerns the appropriate balance between primary and secondary prevention and between the population and high-risk approaches to primary prevention. If the goal is to increase the proportion of the population at low risk and to ensure that all groups benefit, the strategy with the greatest potential is the one directed at the whole population, not just people with high levels of risk factors or established disease (5). All other strategies will, at best, only blunt the epidemics and likely increase inequalities; they will not prevent the epidemics. Even so, with ageing populations, health systems will continue to face the unrelenting demands of costly care, both acute and chronic (see Box 1.3 in Chapter 1).
The ultimate public health policy goal is the reduction of population risk, and since most of the population in most countries is not at the optimal risk level, it follows that the majority of prevention and control resources should be directed towards this goal in the entire population. Evidence is available in support of the cost-effective policies required for the task of making the small -- but powerful and surprisingly rapid -- shifts in risk distributions in entire populations in a favourable direction (1). Similarly, management decisions based on measures of overall risk are more cost-effective than those based on single risk factors.
Untold lives lost are lost unnecessarily because of inadequate acute and long-term management of CVD. Relatively cheap interventions for CVD are available (6), and single combination pills including aspirin and drugs for blood pressure and cholesterol lowering for possible use in chronic care are under development. Even in wealthy countries, however, the potential of these and other interventions for secondary prevention is far from fully utilized. The situation in poorer countries is even less satisfactory. There are many opportunities for coordinated CVD risk reduction, care and long-term management. Smoking cessation and the identification and management of diabetes, for example, are just two priorities. Cost-effective interventions, such as the use of aspirin in people with symptoms of chest pain, would prevent a quarter of the deaths associated with heart attacks and are much more cost-effective than more radical interventions such as revascularization procedures, which are inevitably restricted to a minority of patients with CVD.
Acting now and measuring progress
There have been striking and rapid reductions in CVD death rates in wealthy countries -- especially benefiting the wealthiest and most educated -- because of comprehensive approaches including both improved prevention and the management of high-risk people. Policy interventions in developed and developing countries can lead to a surprisingly rapid response. In Mauritius, government action to encourage consumption of healthy oils resulted in a rapid decrease in population levels of blood cholesterol. In Finland, government agricultural subsidies were used to reduce dairy farming and increase berry production. And in Poland, increased consumption of fresh fruit and vegetables, consequent to changes in the policy environment, were associated with a sharp decline in CVD death rates. A WHO/FAO expert consultation report on diet, nutrition and the prevention of chronic diseases reviewed the evidence and provided recommendations for nutrient intake goals for the prevention of CVD and other noncommunicable diseases (7).
A coherent policy framework, encompassing legislation, regulation and mass education is critical for CVD prevention and control, since individual behaviour change is difficult in the absence of conducive environmental alterations. A suggested stepwise framework for a comprehensive response to CVD prevention and control is outlined in Table 6.1 and can be modified according to national needs, goals and targets.
Unfortunately, in most countries the response to CVD prevention and control is still based on the infectious disease paradigm. Consequently, the global and national capacity to respond to CVD epidemics is woefully inadequate. Few countries have implemented comprehensive prevention and control policies (9) and development of capacity, especially for policy research, has not kept pace with the epidemiological transition. The gaps between the needs for CVD prevention and control and the capacity to meet them will grow even wider unless urgent steps are taken.
Global norms are needed to balance the otherwise unrestrained influences of powerful actors. To promulgate such norms, public health professionals need to learn how to influence the deliberations of bodies such as the World Trade Organization -- where health issues are increasingly considered -- and to develop stronger ways of dealing with products with health impacts. A combination of multistakeholder and intergovernmental codes and other non-binding measures may be required. The Framework Convention on Tobacco Control, described in the following section, is one example of a legally binding global norm.
WHO and governments cannot confront the challenges of CVD prevention and control alone. As with tobacco control, partnerships and interactions with international consumer groups and global commercial multinationals are essential. WHO is developing a Global Strategy on Diet, Physical Activity and Health as a strategic framework within which WHO and Member States can work together across sectors in preventing CVD and other noncommunicable diseases. This population-wide prevention strategy is based on extensive consultations with stakeholders: Member States, the United Nations and intergovernmental organizations, civil society and the private sector.
Globally, there is still only limited advocacy for the CVD prevention and control agenda. What there is tends to be fragmented. The lack of unified advocacy for health promotion compares poorly with the growing dominance of commercial and consumer groups who have placed treatment at the centre of health policy debates and funding priorities. Broader alliances of major health professional bodies, consumer groups and others are needed to promote the prevention of major risk factors for CVD and to track progress to agreed national and global goals -- perhaps modelled on the Millennium Development Goals (see Box 6.1). Since the determinants of CVD are multisectoral, advocacy and action, too, must extend well beyond the health sector. The involvement of nongovernmental organizations in articulating the demand for speedy implementation of policies and programmes relevant to CVD control is critical for catalysing policy change and for mobilizing communities to ensure that the benefits flow to the entire population.
Box 6.1 Measuring progress: integrated surveillance of noncommunicable disease risk factors
Figure 6.1
The goal of surveillance is to monitor emerging patterns and trends in major cardiovascular disease (CVD) and other noncommunicable disease (NCD) risk factors and to measure the effectiveness of prevention interventions in countries. Two tools have been developed for this purpose: the WHO STEPwise approach to Surveillance (STEPS) of noncommunicable disease risk factors (10) and the WHO Global NCD InfoBase (11).
STEPS is a sequential process, starting with gathering information on key health behaviours by the use of questionnaires (Step 1), then moving to simple physical measurements (Step 2), and only then recommending the collection of blood samples for biochemical assessment (Step 3). This framework builds a common approach to defining core variables for surveys, surveillance and monitoring systems. The goal is to achieve data comparability over time and between countries. The methodology has been developed in close collaboration with WHO regional offices and is easily adaptable to the needs of Member States. It offers an entry point for low-income and middle-income countries to get started in surveillance and prevention activities for noncommunicable diseases. By increasing local capacity, STEPS aims to achieve data comparability over time and between countries. Many Member States have now been trained in the STEPS methodology. The approach is designed to build on existing surveillance activities, but can also be introduced as a new methodology to countries where there are no surveillance systems currently in place. Data collected using the STEPwise approach is fed into the WHO Global NCD InfoBase.
The WHO Global NCD InfoBase is a database designed to hold existing country-level data on risk factors of noncommunicable diseases. Its strength is that the data can be displayed and used to derive a single best prevalence estimate for any given country. This approach allows transparency in the use of country data sources. It is a major improvement on previous WHO estimates, which, in the absence of such a relational database, relied on selected studies which may have excluded many available sources and lacked transparency.
While the pace of globalization of the major risks for CVDs is increasing, progress towards CVD prevention and control is slow. Sustained progress will occur only when governments, international agencies, nongovernmental organizations and civil society acknowledge that the scope of public health activities must be rapidly broadened to include CVDs and their risk factors.
The challenge is to work towards the integration of prevention and control of both communicable diseases and CVDs, while acknowledging the different time scales of these epidemics and the competition for limited resources. A place must be found for the prevention and control of CVD on the agenda of health systems led by primary care. At Alma-Ata 25 years ago it was deemed unnecessary. Today, it is indispensable.