Cardiovascular Disease in Non-Western Countries
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《新英格兰医药杂志》
Concern about increasing rates of death and disability due to cardiovascular disease in non-Western countries is often met with skepticism: Do they really constitute a serious public health problem? With justifiable alarm about the spread of human immunodeficiency virus and AIDS and with old foes such as malaria and tuberculosis still posing formidable challenges in many developing countries, it is understandable that epidemics of cardiovascular disease have insidiously established themselves without attracting global attention or local action. The fact that 80 percent of deaths from cardiovascular disease worldwide and 87 percent of related disability currently occur in low-income and middle-income countries, however, indicates the magnitude of the problem. Cardiovascular disease has become the leading cause of death in many developing countries and will soon attain that status in several others.
The high burden of mortality from cardiovascular causes in developing countries (estimated at 9 million in 1990 and expected to increase to 19 million by 20201) is only partially explained by their large populations (see Figure 1). The projected increase in the proportion of all deaths that are due to cardiovascular causes, from about 25 percent in 1990 to more than 40 percent in 2020, signals the advance of the epidemics. China has witnessed a doubling of the number of deaths attributed to circulatory diseases during the past two decades, with the most marked increase among persons 35 to 54 years of age. Over the past 40 years, the prevalence of coronary heart disease in urban India has increased by a factor of six to eight, to about 10 percent among persons 35 to 64 years of age. Stroke is now the dominant type of cardiovascular disease in China, Southeast Asia, and sub-Saharan Africa, whereas coronary heart disease predominates in Latin America, the Middle East, and urban India. As the so-called health transition in these countries progresses, hemorrhagic stroke is being replaced by thrombotic stroke and coronary heart disease as the leading form of cardiovascular disease.
Figure 1. Deaths from Cardiovascular Causes, Worldwide, in 1990 and Estimated for 2020.
Data are from Murray and Lopez.1
In non-Western countries, deaths due to cardiovascular disease tend to occur a decade or two earlier than they do in Western countries; nearly half occur before 70 years of age, whereas only one fifth occur so early in the West — a difference attributable to both the earlier occurrence of cardiovascular events and the lower level of clinical care available.2 The rate of death due to stroke among persons 15 to 59 years of age is three to eight times as high in Tanzania as in England and Wales. Death and disability occurring in midlife have disastrous consequences for families who lose wage earners, and the resulting loss in productivity adversely affects national development. Of the 24 million people expected to die of cardiovascular disease in 2020, about 9.3 million will be between 30 and 69 years of age; most of them will be in non-Western countries.
These epidemics are driven by social and economic changes that have profound effects on living habits. Although sharp shifts in demographic patterns and lifestyle have resulted from urbanization and industrialization, the globalization that constituted the tailwind of the 20th century propelled developing countries into the worldwide epidemic of cardiovascular disease. The change reflects both a demographic shift toward increasing life expectancy and a shift in nutrition: people who live longer have greater exposure to cardiovascular risk factors, and Westernized diets and patterns of physical inactivity result in elevations in blood pressure, body weight, blood sugar levels, and lipid concentrations. A huge increase in the prevalence of diabetes will further increase the burden of cardiovascular disease; India, where nearly 20 million people had diabetes in 1995, will see at least a tripling of that number by 2025. Moreover, the global expansion of the tobacco trade has led to large increases in the rate of smoking.
The levels of these risk factors have increased steeply in most non-Western countries over the past two decades. Although there are some differences among ethnic groups in the interactions between genes and the environment, the available evidence indicates that the main risk factors for cardiovascular disease are relevant to all populations and that most of the risk is environmentally determined. Thus, these trends portend an explosion of atherothrombotic cardiovascular diseases in developing countries. Given the rate at which the distributions of body-mass index and blood cholesterol levels have changed in the Chinese population (see Figure 2), possibly in association with a sharp increase in fat consumption, it is clear that countries like China will see a rapid escalation of the rate of coronary heart disease.
Figure 2. Trends in Mean Total Cholesterol Levels among Persons 25 to 64 Years of Age in Beijing, China.
Data are from the Monitoring Cardiovascular Disease (MONICA) study of the World Health Organization.3 To convert values for cholesterol to milligrams per deciliter, divide by 0.02586.
The epidemics of cardiovascular disease struck the more affluent sections of developing countries first, but as the epidemics mature, the social gradient is reversing, with socioeconomically disadvantaged groups becoming increasingly vulnerable. The poor and the less educated everywhere now use tobacco with greater frequency than the rich and the better educated do. In Brazil, women in lower-income groups have had increasing rates of overweight and obesity since 1989, in contrast to the significant decrease observed in high-income groups. Studies conducted in Indian cities in the past decade have shown that the poor have a higher risk of heart attack than the rich. The poor also have less access to health care; their risk factors are not recognized in a timely fashion; and they often do not receive effective treatment, since public health care is generally restricted to the treatment of infectious diseases. Neglect of the epidemics of cardiovascular disease will heap greater injustice on the poorest of countries and the poorest of people.
Although these developments mirror in many ways the path of the epidemics of cardiovascular disease in Western countries, there are important differences. Whereas the epidemics in the West flowed and ebbed over the course of a century, the health transition in developing countries has been compressed into a few decades. Urbanization is occurring in places with uncorrected poverty and increasing disparities in income, causing the poor to be especially vulnerable, while resource-constrained national health systems are ill equipped to cope with the double burden of infectious and chronic diseases. Globalization accelerates the change, as Western products and models of behavior are increasingly exported to non-Western countries. However, globalization also offers opportunities to facilitate the prevention of cardiovascular disease, through the application of knowledge generated in Western countries: the understanding of risk factors, evidence regarding effective interventions, tools and technology for reducing risk, and new models of healthy behavior that can be promoted through the mass media. Thus, there is an opportunity to alter the pattern of health transition in developing countries by implementing effective measures for prevention and control before the epidemics peak — ideally, permitting a rapid shift to a state in which cardiovascular events occur only or primarily after 70 years of age.
A concerted public health response must integrate population-based prevention strategies and cost-effective clinical care, since the health systems of developing countries can ill afford the demands of technology-intensive treatments. The population approach is more rewarding and sustainable in the medium and long term, since even small reductions in each risk factor can add up to huge reductions in the rate of cardiovascular events. And if healthy behavior is established as a desirable norm in a society, it can have a multigenerational effect.
There are differences of opinion, however, regarding whether population-level interventions should rely principally on behavioral change governed by the personal choices of well-informed people or should operate through policy interventions that modify behavior through social and economic determinants. Western countries generally favor the personal-choice approach, but this approach assumes that healthy choices are widely available and affordable and that it is easy to educate consumers about the merits and demerits of each option. The North Karelia project in Finland provides a successful model of behavioral change through community health education combined with industry-level interventions for providing healthful food choices. Such programs, however, may be less effective in non-Western societies, where personal choice is limited by lack of awareness and highly restricted options.
Policy-level interventions have proved effective in bringing about population-wide behavioral change and risk reduction even in the short term. In Mauritius, governmental action to substitute soybean oil for palm oil as the subsidized, rationed oil resulted in a remarkable reduction in cholesterol levels. Changes in economic policy that increased the availability of fresh fruits and vegetables and helped to substitute vegetable fats for animal fats led to a sharp decline in mortality from cardiovascular causes in Poland. Non-Western countries must implement policies that will help to reduce the consumption of tobacco, salt, and unhealthful fats and increase the consumption of fruits and vegetables, through production and pricing mechanisms that increase options and influence consumer choice. But policy interventions will have limited success if the community is unwilling to accept them. Hence, the top-down approach of enabling legislation and regulation must be complemented by a bottom-up approach of community mobilization through health education. Measures taken in Western countries to protect nonsmokers from exposure to environmental tobacco smoke illustrate such a combined approach.
At the same time, people with a high risk of cardiovascular disease or clinical manifestations of disease need protection from premature death and prolonged disability. Evidence-based, context-specific, and resource-sensitive interventions must be cost-effectively integrated into all levels of health care, to strengthen both primary and secondary prevention of cardiovascular disease. The extensive use of aspirin in primary care settings for the treatment of suspected myocardial infarction can save millions of lives at low cost (about $3 per life saved, in India). Blood-pressure–lowering therapies reduce overall cardiovascular risk and have a substantial effect on mortality from coronary heart disease and stroke, and smoking cessation effectively reduces cardiovascular risk. Operational research is required to ensure the effective integration of such therapies and community-based preventive strategies into the health care systems of non-Western countries. The Initiative for Cardiovascular Health Research in the Developing Countries is a multi-institutional, international program that works to stimulate, support, and strengthen such research.
Epidemics of cardiovascular disease in non-Western countries present complex challenges but also great opportunities. Seldom in the history of human health have we been endowed with such foresight about our destiny and forearmed with such power to change it. It is a challenge to human intellect and enterprise to apply our knowledge creatively and cost-effectively to minimize the burden of cardiovascular disease throughout the world.
Source Information
From the All India Institute of Medical Sciences, New Delhi.
References
Murray CJL, Lopez AD. The global burden of disease: a comprehensive assessment of mortality and disability from diseases, injuries, and risk factors in 1990 and projected to 2020. Cambridge, Mass.: Harvard University Press, 1996.
Reddy KS. Cardiovascular diseases in the developing countries: dimensions, determinants, dynamics and directions for public health action. Public Health Nutr 2002;5:231-237.[CrossRef][ISI][Medline]
The world health report 2002: reducing risks, promoting healthy life. Geneva: World Health Organization, 2002.(K. Srinath Reddy, D.M.)
The high burden of mortality from cardiovascular causes in developing countries (estimated at 9 million in 1990 and expected to increase to 19 million by 20201) is only partially explained by their large populations (see Figure 1). The projected increase in the proportion of all deaths that are due to cardiovascular causes, from about 25 percent in 1990 to more than 40 percent in 2020, signals the advance of the epidemics. China has witnessed a doubling of the number of deaths attributed to circulatory diseases during the past two decades, with the most marked increase among persons 35 to 54 years of age. Over the past 40 years, the prevalence of coronary heart disease in urban India has increased by a factor of six to eight, to about 10 percent among persons 35 to 64 years of age. Stroke is now the dominant type of cardiovascular disease in China, Southeast Asia, and sub-Saharan Africa, whereas coronary heart disease predominates in Latin America, the Middle East, and urban India. As the so-called health transition in these countries progresses, hemorrhagic stroke is being replaced by thrombotic stroke and coronary heart disease as the leading form of cardiovascular disease.
Figure 1. Deaths from Cardiovascular Causes, Worldwide, in 1990 and Estimated for 2020.
Data are from Murray and Lopez.1
In non-Western countries, deaths due to cardiovascular disease tend to occur a decade or two earlier than they do in Western countries; nearly half occur before 70 years of age, whereas only one fifth occur so early in the West — a difference attributable to both the earlier occurrence of cardiovascular events and the lower level of clinical care available.2 The rate of death due to stroke among persons 15 to 59 years of age is three to eight times as high in Tanzania as in England and Wales. Death and disability occurring in midlife have disastrous consequences for families who lose wage earners, and the resulting loss in productivity adversely affects national development. Of the 24 million people expected to die of cardiovascular disease in 2020, about 9.3 million will be between 30 and 69 years of age; most of them will be in non-Western countries.
These epidemics are driven by social and economic changes that have profound effects on living habits. Although sharp shifts in demographic patterns and lifestyle have resulted from urbanization and industrialization, the globalization that constituted the tailwind of the 20th century propelled developing countries into the worldwide epidemic of cardiovascular disease. The change reflects both a demographic shift toward increasing life expectancy and a shift in nutrition: people who live longer have greater exposure to cardiovascular risk factors, and Westernized diets and patterns of physical inactivity result in elevations in blood pressure, body weight, blood sugar levels, and lipid concentrations. A huge increase in the prevalence of diabetes will further increase the burden of cardiovascular disease; India, where nearly 20 million people had diabetes in 1995, will see at least a tripling of that number by 2025. Moreover, the global expansion of the tobacco trade has led to large increases in the rate of smoking.
The levels of these risk factors have increased steeply in most non-Western countries over the past two decades. Although there are some differences among ethnic groups in the interactions between genes and the environment, the available evidence indicates that the main risk factors for cardiovascular disease are relevant to all populations and that most of the risk is environmentally determined. Thus, these trends portend an explosion of atherothrombotic cardiovascular diseases in developing countries. Given the rate at which the distributions of body-mass index and blood cholesterol levels have changed in the Chinese population (see Figure 2), possibly in association with a sharp increase in fat consumption, it is clear that countries like China will see a rapid escalation of the rate of coronary heart disease.
Figure 2. Trends in Mean Total Cholesterol Levels among Persons 25 to 64 Years of Age in Beijing, China.
Data are from the Monitoring Cardiovascular Disease (MONICA) study of the World Health Organization.3 To convert values for cholesterol to milligrams per deciliter, divide by 0.02586.
The epidemics of cardiovascular disease struck the more affluent sections of developing countries first, but as the epidemics mature, the social gradient is reversing, with socioeconomically disadvantaged groups becoming increasingly vulnerable. The poor and the less educated everywhere now use tobacco with greater frequency than the rich and the better educated do. In Brazil, women in lower-income groups have had increasing rates of overweight and obesity since 1989, in contrast to the significant decrease observed in high-income groups. Studies conducted in Indian cities in the past decade have shown that the poor have a higher risk of heart attack than the rich. The poor also have less access to health care; their risk factors are not recognized in a timely fashion; and they often do not receive effective treatment, since public health care is generally restricted to the treatment of infectious diseases. Neglect of the epidemics of cardiovascular disease will heap greater injustice on the poorest of countries and the poorest of people.
Although these developments mirror in many ways the path of the epidemics of cardiovascular disease in Western countries, there are important differences. Whereas the epidemics in the West flowed and ebbed over the course of a century, the health transition in developing countries has been compressed into a few decades. Urbanization is occurring in places with uncorrected poverty and increasing disparities in income, causing the poor to be especially vulnerable, while resource-constrained national health systems are ill equipped to cope with the double burden of infectious and chronic diseases. Globalization accelerates the change, as Western products and models of behavior are increasingly exported to non-Western countries. However, globalization also offers opportunities to facilitate the prevention of cardiovascular disease, through the application of knowledge generated in Western countries: the understanding of risk factors, evidence regarding effective interventions, tools and technology for reducing risk, and new models of healthy behavior that can be promoted through the mass media. Thus, there is an opportunity to alter the pattern of health transition in developing countries by implementing effective measures for prevention and control before the epidemics peak — ideally, permitting a rapid shift to a state in which cardiovascular events occur only or primarily after 70 years of age.
A concerted public health response must integrate population-based prevention strategies and cost-effective clinical care, since the health systems of developing countries can ill afford the demands of technology-intensive treatments. The population approach is more rewarding and sustainable in the medium and long term, since even small reductions in each risk factor can add up to huge reductions in the rate of cardiovascular events. And if healthy behavior is established as a desirable norm in a society, it can have a multigenerational effect.
There are differences of opinion, however, regarding whether population-level interventions should rely principally on behavioral change governed by the personal choices of well-informed people or should operate through policy interventions that modify behavior through social and economic determinants. Western countries generally favor the personal-choice approach, but this approach assumes that healthy choices are widely available and affordable and that it is easy to educate consumers about the merits and demerits of each option. The North Karelia project in Finland provides a successful model of behavioral change through community health education combined with industry-level interventions for providing healthful food choices. Such programs, however, may be less effective in non-Western societies, where personal choice is limited by lack of awareness and highly restricted options.
Policy-level interventions have proved effective in bringing about population-wide behavioral change and risk reduction even in the short term. In Mauritius, governmental action to substitute soybean oil for palm oil as the subsidized, rationed oil resulted in a remarkable reduction in cholesterol levels. Changes in economic policy that increased the availability of fresh fruits and vegetables and helped to substitute vegetable fats for animal fats led to a sharp decline in mortality from cardiovascular causes in Poland. Non-Western countries must implement policies that will help to reduce the consumption of tobacco, salt, and unhealthful fats and increase the consumption of fruits and vegetables, through production and pricing mechanisms that increase options and influence consumer choice. But policy interventions will have limited success if the community is unwilling to accept them. Hence, the top-down approach of enabling legislation and regulation must be complemented by a bottom-up approach of community mobilization through health education. Measures taken in Western countries to protect nonsmokers from exposure to environmental tobacco smoke illustrate such a combined approach.
At the same time, people with a high risk of cardiovascular disease or clinical manifestations of disease need protection from premature death and prolonged disability. Evidence-based, context-specific, and resource-sensitive interventions must be cost-effectively integrated into all levels of health care, to strengthen both primary and secondary prevention of cardiovascular disease. The extensive use of aspirin in primary care settings for the treatment of suspected myocardial infarction can save millions of lives at low cost (about $3 per life saved, in India). Blood-pressure–lowering therapies reduce overall cardiovascular risk and have a substantial effect on mortality from coronary heart disease and stroke, and smoking cessation effectively reduces cardiovascular risk. Operational research is required to ensure the effective integration of such therapies and community-based preventive strategies into the health care systems of non-Western countries. The Initiative for Cardiovascular Health Research in the Developing Countries is a multi-institutional, international program that works to stimulate, support, and strengthen such research.
Epidemics of cardiovascular disease in non-Western countries present complex challenges but also great opportunities. Seldom in the history of human health have we been endowed with such foresight about our destiny and forearmed with such power to change it. It is a challenge to human intellect and enterprise to apply our knowledge creatively and cost-effectively to minimize the burden of cardiovascular disease throughout the world.
Source Information
From the All India Institute of Medical Sciences, New Delhi.
References
Murray CJL, Lopez AD. The global burden of disease: a comprehensive assessment of mortality and disability from diseases, injuries, and risk factors in 1990 and projected to 2020. Cambridge, Mass.: Harvard University Press, 1996.
Reddy KS. Cardiovascular diseases in the developing countries: dimensions, determinants, dynamics and directions for public health action. Public Health Nutr 2002;5:231-237.[CrossRef][ISI][Medline]
The world health report 2002: reducing risks, promoting healthy life. Geneva: World Health Organization, 2002.(K. Srinath Reddy, D.M.)