CHAPTER 1. Global Burden of Cardiovascular Disease

Transcription

1 1 PART I General Considerations of Cardiovascular Disease The Epidemiological Transitions, 1 Economic, Social, and Demographic Transitions, 4 Rate of Change of the Epidemiological Transition, 5 The Epidemiological Transition in the United States, 5 The Age of Pestilence and Famine, 5 The Age of Receding Pandemics, 6 The Age of Degenerative and Man-Made Diseases, 6 Growth of the Health Care Industry, 6 Current Worldwide Variations in the Global Burden of Cardiovascular Disease, 8 Established Market Economies, 8 Emerging Market Economies, 10 Developing Economies, 10 Global Trends in Cardiovascular Disease, 12 Expectations for 2020, 12 Regional Trends in Risk Factors, 13 Tobacco, 13 Diet, 14 Physical Inactivity, 14 Obesity, 14 Lipid Levels, 15 Hypertension, 15 Diabetes Mellitus, 16 Future Challenges, 16 Established Market Economies, 16 Emerging Market Economies, 17 Developing Economies, 17 Summary and Conclusions, 18 References, 18 CHAPTER 1 Global Burden of Cardiovascular Disease J. Michael Gaziano Over the past two centuries, the Industrial and Technological Revolutions and their associated economic and social transformations have resulted in dramatic shifts in the diseases responsible for illness and death. Cardiovascular disease (CVD) has emerged as the dominant chronic disease in many parts of the world, and early in the 21st century it is predicted to become the main cause of disability and death worldwide. In this chapter, trends in global patterns of disease and the increasing burden of CVD are summarized. The chapter begins with an explanation of the concept of the epidemiological transition, followed by a synopsis of this transition in the United States. This is followed by reviews of the current burden of cardiovascular and other chronic diseases in various regions of the world and global trends in the rates of CVD as well as rates of risk behaviors and factors. The chapter ends with a discussion of the diverse challenges that the increasing burden of CVD poses for the various regions of the world and potential solutions to this global problem. The Epidemiological Transitions At the beginning of the 20th century, CVD accounted for less than 10 percent of all deaths worldwide. At the beginning of the 21st century, CVD accounts for nearly half of all deaths in the developed world and 25 percent in the developing world. 1,2 By 2020, it is predicted that CVD will claim 25 million lives annually and that coronary heart disease (CHD) will surpass infectious disease as the world s number one cause of death and disability. This global rise in CVD is the result of a dramatic shift in the health status of individuals around the world during the course of the 20th century. Equally important, there has been an unprecedented transformation in the dominant disease profile, or the distribution of diseases responsible for the majority of cases of death and debility. Before 1900, infectious diseases and malnutrition were the most common causes of death. These have been gradually supplanted in some (mostly developed) countries by chronic diseases such as CVD and cancer, thanks largely to improved nutrition and public health measures. As this trend spreads to and continues in developing countries, CVD will dominate as the major cause of death by 2020, accounting for at least one in every three deaths (Fig. 1 1). 2 This shift in the diseases that account for the lion s share of mortality and morbidity is known as the epidemiological transition. 3,4 Never occurring in isolation, the epidemiological transition is tightly intertwined with changes in personal and collective wealth (economic transition), social structure (social transition), and demographics (demographic transition). Because the epidemiological transition is linked to the evolution of social and economic forces, it takes place at different rates around the world. At the beginning of the third millennium, national health and disease profiles 1

2 2 EstME 1990 EstME 2020 DevE 1990 DevE 2020 INJ CVD ONC CMPN FIGURE 1 1 Changing pattern of mortality, 1990 to EstMe, Established market economies; DevE, developing economies; INJ, injury; CVD, cardiovascular disease; ONC, other noncommunicable diseases; CMPN, communicable, maternal, perinatal, and nutritional diseases. (From Murray CJL, Lopez AD: The Global Burden of Disease. Cambridge, MA, Harvard School of Public Health, 1996.) vary widely by country and by region. For example, life expectancy in Japan (81.4 years) is more than twice that in Sierra Leone (34.2 years). 1 In a similar vein, communicable, infectious, maternal, perinatal, and nutritional diseases the group I diseases defined by Murray and Lopez in their comprehensive analysis of the global burden of disease 2 account for just 6 percent of deaths in so-called developed countries, compared with 33 percent in India. 2 The vast differences in burden of disease are readily apparent across three broad economic and geographical sectors of the world (Table 1 1). These include the established market economies (EstME) of Western Europe, North America, Australia, New Zealand, and Japan; the emerging market economies (EmgME) of the former socialist states of Eastern Europe; and the developing economies (DevE), which can further be subdivided into six geographical regions: China, India, other Asian countries and islands, sub-saharan Africa, the Middle Eastern Crescent, and Latin America and the Caribbean. Currently, CVD is responsible for 45 percent of all deaths in EstME, 55 percent of all deaths in EmgME, and only 23 percent of the deaths in DevE. An excellent model of the epidemiological transition has been developed by Omran. 3 He divides the transition into three basic ages: pestilence and famine, receding pandemics, and degenerative and man-made diseases (Table 1 2). Olshansky and Ault added a fourth stage, delayed degenerative diseases. 4 It is possible that a fifth stage (discussed later) may be emerging in some countries. Although any specific country or region enters these ages at different times, the progression from one to another tends to proceed in a predictable manner. The Age of Pestilence and Famine From the epidemiological standpoint, humans evolved under conditions of pestilence and famine and have lived with them for most of recorded history. This age is characterized by the predominance of malnutrition and infectious disease and by the infrequency of CVD as a cause of death. High fertility rates are offset by high infant and child mortality, resulting in a mean life expectancy on the order of approximately 30 years. In the countries that eventually became today s established market economies, the transition through the age of pestilence and famine was relatively slow, beginning in the late 1700s and developing throughout the 1800s. Competing influences prolonged the transition improvements in the food supply early in the Industrial Revolution that by themselves would have reduced mortality were offset by concentration of the population in urban centers, which led to increases in mortality due to communicable diseases such as tuberculosis, cholera, dysentery, and influenza. Although the transition through the age of pestilence and famine occurred much later in the emerging market economies and the developing economies, it has also taken place more rapidly, driven largely by the transfer of low-cost agricultural products and technologies and well-established, lower-cost public health technologies. Much of the developing world has emerged from the age of pestilence and famine. In sub-saharan Africa and parts of India, however, malnutrition and infectious disease remain leading causes of death. The Age of Receding Pandemics Rising wealth and the resultant increase in the availability of food help usher in the second phase of the epidemiological transition. Improved nutrition decreases early deaths TABLE 1 1 Burden of Disease for the Three Economic Regions of the World Communicable, Other Maternal, Population (Millions) Noncommu- Perinatal, (Percentage of Total Cardiovascular nicable and Nutritional World Population) Disease (%) Diseases* (%) Conditions (%) Injuries (%) Sector EstME 798 (15.2) 874 (12.4) EmgME 346 (6.6) 363 (5.2) DevE 4124 (78.3) 5764 (82.3) Adapted from Murray CJL, Lopez AD: The Global Burden of Disease. Cambridge, MA, Harvard School of Public Health, *Includes cancer, diabetes, neuropsychiatric conditions, congenital anomalies, and respiratory, digestive, genitourinary, and musculoskeletal diseases. EstME = established market economies: United States, Canada, Western Europe, Japan, Australia, and New Zealand. EmgME = emerging market economies: former socialist states of Russian Federation. DevE = developing market economies: China, India, other Asian countries and islands, sub-saharan Africa, Middle Eastern Crescent, and Latin America and the Caribbean.

3 TABLE 1 2 Four Typical Stages of the Epidemiological Transition Typical Proportion of Deaths due to Cardiovascular Predominant Types of Stage Description Disease (%) Cardiovascular Disease Pestilence and Predominance of malnutrition and infectious <10 Rheumatic heart disease, famine diseases as causes of death; high rates of cardiomyopathies due to infant and child mortality; low mean life infection and malnutrition expectancy Receding pandemics Improvements in nutrition and public health Rheumatic valvular disease, lead to decrease in rates of deaths due to hypertension, CHD, malnutrition and infection; precipitous stroke decline in infant and child mortality rates Degenerative and Increased fat and caloric intake and decreased CHD, stroke man-made diseases physical activity lead to emergence of hypertension and atherosclerosis; with increased life expectancy, mortality from chronic, noncommunicable diseases exceeds mortality from malnutrition and infectious diseases Delayed degenerative Cardiovascular diseases and cancer are the CHD, stroke, congestive diseases major causes of morbidity and mortality; heart failure better treatment and prevention efforts help avoid deaths among those with disease and delay primary events. Age-adjusted CVD mortality declines; CVD affecting older and older individuals 3 Global Burden of Cardiovascular Disease CHD = coronary heart disease; CVD = cardiovascular disease. Adapted from Omran AR: The epidemiologic transition: A theory of the epidemiology of population change. Milbank Mem Fund Q 49:509, 1971; and Olshansky SJ, Ault AB: The fourth stage of the epidemiologic transition: The age of delayed degenerative diseases. Milbank Q 64:355, due to malnutrition and may also reduce susceptibility to infectious diseases. Increased personal and public wealth is associated with public health measures that contribute still further to declines in infectious diseases. These advances, in turn, increase the productivity of the average worker, further improving the economic situation. The change most characteristic of this phase is a precipitous decline in infant and child mortality accompanied by a substantial increase in life expectancy. Examples of countries in this phase of the epidemiological transition are the United States early in the 20th century and China today, where approximately 29 percent of deaths are due to CVD and only 16 percent are due to communicable disease. 2 Changes in nutrition and other aspects of life style that cause lower rates of communicable, maternal, perinatal, and nutritional diseases eventually lead to a greater incidence of CVD. The Age of Degenerative and Man-Made Diseases Continued improvements in economic circumstances, combined with urbanization and radical changes in the nature of work-related activities, lead to dramatic life-style changes in diet, activity levels, and behaviors such as smoking. During the age of pestilence and famine, most of the population is deficient in total caloric intake relative to daily caloric expenditure. Easier access to less expensive foods and increased fat content increase total caloric intake, whereas mechanization results in lower daily caloric expenditure. This disparity leads to a higher mean body mass index, blood pressure, and levels of plasma lipids and blood sugar. These changes set the stage for the emergence of hypertensive diseases and atherosclerosis. Cancer rates also rise rapidly during the age of degenerative and man-made diseases. As the average life expectancy increases beyond 50 years, mortality from largely chronic noncommunicable diseases dominated by CVD exceeds mortality from malnutrition and infectious diseases. 5,6 Countries currently in this phase of the epidemiological transition are the emerging market economies of the former Soviet socialist states. The Age of Delayed Degenerative Diseases In the fourth phase of the epidemiological transition, CVD and cancer remain the major causes of morbidity and mortality. In the industrialized nations, however, major technological advances such as coronary care units, bypass surgery, percutaneous coronary interventions, and thrombolytic therapy are available to manage the acute manifestations of CVD, and preventive strategies such as smoking cessation and blood pressure management are widely implemented. As a result of better treatment and widespread primary and secondary prevention efforts, deaths are prevented among people with disease and primary events are delayed. Life expectancy continues to creep upward as age-adjusted CVD mortality tends to decline, with the average age of people affected by CVD getting increasingly older. Is There a Fifth Phase of the Epidemiological Transition? Troubling trends in certain risk behaviors and risk factors may be foreshadowing a new phase of the epidemiological transition. In many parts of the industrialized world, physical activity continues to decline while total caloric intake increases at alarming rates, with the combination resulting in an epidemic of obesity. As a result, rates of type 2 diabetes, hypertension, and lipid abnormalities associated with obesity are increasing. These trends are particularly evident in children. These changes are occurring at a time when measurable improvements in other risk behaviors and risk factors such as smoking have slowed. If these risk factor trends continue, age-adjusted CVD mortality rates, which have declined over the past several decades in developed countries, could increase in the coming years. Evidence that we are approaching an inflection point in the CVD mortality curves is

4 4 provided by the slowing of the rate of decline in the past few years. This is especially true for age-adjusted stroke death rates. Changes in Cardiovascular Disease through the Epidemiological Transitions During the transition from the age of pestilence and famine to the age of delayed degenerative diseases, changes occur in both the character of CVD and total rates of CVD. 6 During the age of pestilence and famine, CVD accounts for only 5 to 10 percent of mortality, with the major forms of CVD related to infection and malnutrition, largely rheumatic heart disease and the infectious and nutritional cardiomyopathies. Given the potentially long latent period of these diseases, they are apparent well into the age of receding pandemics, when they persist as major causes of death along with emerging hypertensive heart disease and stroke. During the age of receding pandemics, CVD accounts for 10 to 35 percent of deaths. CHD rates tend to be low relative to stroke rates. In addition, risk behaviors and risk factors that will foreshadow the next phase become more widespread. During the age of degenerative and man-made diseases, increased caloric intake (particularly from saturated animal fats and processed vegetable fats), reduced daily activity, increased smoking rates, and related changes in the prevalence of hypertension, diabetes, and hyperlipidemia result in further increases in hypertensive diseases and rapid increases in CHD and peripheral vascular disease. During this phase, 35 to 65 percent of all deaths are due to CVD. Typically, the rate of CHD deaths greatly exceeds that of stroke by a ratio of 2 :1 to 3 :1. In the fourth phase of the epidemiological transition, the age of delayed degenerative diseases, age-adjusted death rates from CVD begin to fall, leveling off somewhere below 50 percent of total mortality. The decline in stroke rates tends to precede the decline for CHD; thus, the ratio of CHD to stroke deaths increases, typically to between 2 :1 and 5 :1 (Fig. 1 2). The decline in CVD rates is the result of two factors: better access to health technology and adoption of healthier life styles. Improvements in health technology and better access to it decrease the likelihood of death among patients Rate Year Total cardiovascular disease Coronary heart disease FPO Diseases of the heart Stroke FIGURE 1 2 Increase and decline in heart disease rates through the epidemiological transition in the United States, 1900 to Rate is per 100,000 population, standardized to the 1940 U.S. population. Diseases are classified according to International Classification of Diseases (ICD) codes in use when the deaths were reported. ICD classification revisions occurred in 1910, 1921, 1930, 1939, 1949, 1958, 1968, and Death rates before 1933 do not include all states. Comparability ratios were applied to rates for 1970 and (From Achievements in public health, : Decline in deaths from heart disease and stroke United States, MMWR Morbid Mortal Wkly Rep 48:649, 1999.) presenting with acute manifestations of atherosclerotic disease, although better survival means more and more individuals living longer with conditions such as angina pectoris, congestive heart failure, and cardiac arrhythmias. Reductions in risk behaviors and factors may make even greater contributions to the decline in age-adjusted rates of death. In many cases, these are the result of concerted efforts by public health and health care communities. In other cases, secular trends also play a role. For example, the widespread availability of fresh fruits and vegetables all year long in developed countries, and thus increased consumption, may have contributed to declining mean cholesterol levels before effective drug therapy was widely available. In general, however, even though age-adjusted rates of CVD continue to decline during the final phase of the epidemiological transition, the prevalence of CVD increases as the population ages. ECONOMIC, SOCIAL, AND DEMOGRAPHIC TRANSITIONS As mentioned earlier, several parallel transformations accompany the epidemiological transition. These include economic, demographic, and social transitions that pave the way for major shifts in a population s health and the nature of the diseases that account for most of the mortality and morbidity. ECONOMIC TRANSITION. The economic transition is characterized by rising levels of personal wealth.this is usually reflected in increasing per capita income, per capita gross domestic product (GDP), or gross national product (GNP). SOCIAL TRANSITION. The social transition is driven by industrialization and the changes that accompany it, including urbanization, the development of a public health infrastructure, wider access to health care, and increasing application of health technologies. Industrialization tends to spark a large number of social changes. It is typically accompanied by urbanization, a major social force that has a significant impact on the epidemiological transition. Urbanization affects living standards and life style and affords the opportunity to develop organized health care systems. In virtually every region of the world, there has been a shift from rural to urban life. For example, in the United States, 60 percent of the population lived in rural settings at the beginning of the 20th century compared with only 20 percent at the beginning of the 21st century. In Asia, Africa, and Latin America, a similar shift has occurred over the second half of the 20th century (Fig. 1 3). DEMOGRAPHIC TRANSITION. Demographic transition refers to shifts in the age structure of a population due to declining fertility and increased survival. During the age of pestilence and famine, individuals 20 years of age and younger may account for 40 to 50 percent of the Billions of people Africa Asia Europe LA/C NA FIGURE 1 3 Number of people living in urban areas, 1950, 1975, 2000, and LA/C, Latin America and Caribbean; NA, North America. (From Population Division, Department of Economic and Social Affairs: World Urbanization Prospects: The 2001 Revision. New York, United Nations Secretariat, Number ESA/P/WP.173.)

5 population.as child and infant mortality rates are reduced in the age of receding pandemics, rapid gains are seen in life expectancy, and the proportion of individuals 20 years of age and younger decreases. Declines in mortality rates are generally followed by declining fertility rates, further flattening the shape of the population distribution curve. As population growth rates fall, the mean age of the population continues to rise slowly as individuals live longer. The life-style changes associated with the economic and social transitions cause shifts in the profile of risk behaviors and risk factors for disease.these include decreased physical activity, increased smoking, and dramatic changes in diet. RATE OF CHANGE OF THE EPIDEMIOLOGICAL TRANSITION Several factors influence how early or how quickly the epidemiological transition occurs in a given country or region. (1) The rate of economic growth relative to population growth affects the rate of adoption of life styles characteristic of established market economies. (2) Regional economic influences can cause great disparities in the rates of transition within a region. (3) The development of low-cost public health technologies, as well as falling costs of unhealthy aspects of the Western life style such as cigarette smoking and consumption of highly processed food, permits currently developing countries to make transitions more rapidly. SOCIOECONOMIC CLASS. Even within a given country,segments of the population may undergo the transition at varying rates.these factors are related to economic, social, or cultural factors. In fact, epidemiological transitions occur at different rates across economic groups, generally beginning among those with higher socioeconomic status and eventually spreading to those with lower socioeconomic status.the decline in rates of malnutrition and communicable diseases as well as the rise in coronary risk factors and behaviors occur first in the privileged classes; increases in rates of stroke and CHD soon follow. Later, as the middle class grows, the epidemiological transition spreads to a broad enough sector of the population to have a measurable impact on population rates. As more and more of the burgeoning middle class passes through the second and third phases of the transition, CVD and cancer rates become the population s dominant causes of death and disability. People in the lower socioeconomic strata tend to acquire the risk factors and behaviors last, in part because of their economic situation and in part because they tend to engage in more physical activity at work. Compared with people in the upper and middle socioeconomic strata, those in the lowest stratum are less likely to have access to advanced treatments and to acquire and apply information on modification of risk factors and behaviors. Thus, CVD mortality rates decline later among those with lower socioeconomic status. In a developed country such as Canada, for example, CVD mortality rates are highest among the poorest individuals (Fig. 1 4). 7 The Epidemiological Transition in the United States Like other established market economies, the United States has proceeded through four stages of the epidemiological transition. Recent trends, however, suggest that the rates of decline of some chronic and degenerative diseases have (rates have) slowed, suggesting the possibility that the United States is entering a fifth phase characterized by the epidemic of obesity. Given the large amount of economic, social, demographic, and health data available (Table 1 3), the United States is used as a reference point for later comparisons. THE AGE OF PESTILENCE AND FAMINE The United States, like virtually all other countries and regions, was born into pestilence and famine. Infectious diseases killed many of the earliest immigrants to the New World. About half of the Pilgrims arriving in the New World in November of 1620 died of infection and malnutrition by the following spring. In addition, the infectious diseases the immigrants brought with them from Europe had a devastating impact on Native American populations. At the end of the 1800s, the U.S. economy was still largely agrarian, with more than 60 percent of the population living in rural settings. However, industrialization and urbanization were well under way. Per capita income was increasing, and the food supply was improving. Modest gains in life expectancy were apparent throughout the 19th century. By 1900, life expectancy had increased to 47.8 years for men and 50.7 years for women. 8 Infectious diseases largely tuberculosis, pneumonia, and diarrheal diseases accounted for more deaths than any other cause. 9 CVD accounted for less than 10 percent of all deaths. Tobacco products were out of the economic reach of a large segment of the population. THE AGE OF RECEDING PANDEMICS Early in the 20th century, the pace of industrialization accelerated. The shift from a rural, agriculture-based economy to an urban, industrybased economy had a number of consequences on cardiovascular risk behaviors and factors. Food supplies had become abundant, but urbanization required a dramatic shift in dietary staples.the railway network in place at the turn of the century was capable of moving foodstuffs from the farm to the city. But because the trains were not refrigerated, perishable foodstuffs such as fresh fruits and vegetables could not readily be transported, whereas cereal grains and livestock could. Large slaughter houses and meat-packing plants were established in or near urban areas. As a result, consumption of fresh fruits and vegetables declined and consumption of meat and grains increased, resulting in diets that were higher in fat and processed carbohydrates. 10 In addition, the manufacture of factory-rolled cigarettes made them more portable and more affordable for the mass population. 11 RAPID SOCIAL CHANGES. The population of urban areas outnumbered that of rural areas for the first time by By 1930, 56 percent of the population was living in or near urban centers. Infectious disease mortality rates had fallen dramatically, from a crude death rate of approximately 800 per 100,000 population in 1900 to approximately 340 per 100,000 people. 9 Largely as a result of rapidly declining infant,childhood, and adolescent mortality from malnutrition and infectious diseases, life expectancy increased by 10 years between 1900 and 1930, to 57.8 years for men and 61.1 years for women.at the same time, cigarette smoking was on the rise. Age-adjusted CVD mortality rates, at approximately 390 per 100,000 people, were in the midst of their steady climb up from slightly more than 300 per 100,000 people in This increase was largely driven by rapidly rising CHD rates. EMERGENCE OF A PUBLIC HEALTH INFRASTRUCTURE. By 1900, a public health infrastructure had emerged: 40 states had health departments and many larger towns had major public works efforts to improve water supply and sewage systems. 9 Municipal use of chlorine to disinfect water was becoming widespread, and improvements in food handling such as pasteurization were introduced. 12 The health care system was growing but still largely comprised general practitioners providing care in the office or home; hospitals were largely for the indigent.the Flexner Report of 1910, which took a careful look at the quality of medical education in the United States and Canada, 13 was the first step toward organized quality improvement in health care personnel that, along with other public health changes,was responsible for dramatic declines in infectious disease mortality rates throughout the century (Fig. 1 5). THE AGE OF DEGENERATIVE AND MAN-MADE DISEASES By the middle of the 20th century, the United States was predominantly an urban, industrial economy, with 64 percent of the population Standardized mortality ratio Poorest Poor Middle Rich Richest Income FIGURE 1 4 Cardiovascular disease standardized mortality ratios by neighborhood income for Canadians of European ancestry, ages 35 to 74, in 1986 and (From Sheth T, Nair C, Nargundjar M, et al: Cardiovascular and cancer mortality among Canadians of European, south Asian, and Chinese origin from 1979 to 1993: An analysis of 1.2 million deaths. Can Med Assoc J 161:132, 1999.) 5 Global Burden of Cardiovascular Disease

6 6 TABLE 1 3 Trends in the United States During the 20th Century Population (millions) Median income (real dollars) NA $15,050 (1947) $26,333 $29,058 Age-adjusted cardiovascular disease mortality (n/100,000) Age-adjusted coronary heart disease mortality (n/100,000) NA NA Age-adjusted stroke mortality (n/100,000) Urbanization (%) Life expectancy (yr) Smoking Cigarettes per capita (n) Smokers (%) NA NA Total caloric intake (kcal) Fat intake (% of total calories) Cholesterol level (mg/dl) NA NA Overweight or obese (%) NA NA NA = not available. Sources: Population: US Census Bureau. Per capita income: U.S. Bureau of the Census: Current Population Reports, P60-203, Measuring 50 Years of Economic Change Using the March Current Population Survey. Washington, DC, U.S. Government Printing Office, 1998; and U.S. Bureau of the Census: Money Income in the United States, 2000, P Washington, DC, U.S. Government Printing Office, Cardiovascular disease, coronary heart disease, stroke mortality: Morbidity & Mortality: 2002 Chart Book on Cardiovascular, Lung, and Blood Diseases. Betuesda, MD, National Heart, Lung, and Blood Institute, Urbanization: Measuring America: The Decennial Censuses, 1790 to 2000: U.S. Bureau of the Census, Life expectancy: Arias E: United States life tables, In National Vital Statistics Report vol 51, no 3. Atlanta, GA, National Center for Health Statistics, Centers for Disease Control and Prevention, Smoking: Federal Trade Commission: Cigarette report for ( Accessed on 1 July Total caloric intake and fat intake: Nutrient content of the US food supply, : a summary. Washington, DC, US Department of Agriculture, 1998; and Kennedy ET, Bowman SA, Powell R: Dietary-fat intake in the US population. J Am Coll Nutr 18:207, Cholesterol level and obesity: National Center for Health Statistics: Health, United States, ( Accessed on 15 July living in urban and suburban settings.with continued mechanization and urbanization, activity levels declined considerably. The rise of suburbs meant that more and more people were driving to work or to shopping rather than walking or bicycling. Prevalence of smoking, one of the major contributors to premature mortality and chronic disease, hit its zenith among adult men at 57 percent in 1955 and among women 10 years later at 34 percent. 14 Annual per capita consumption of cigarettes peaked in 1963 at 4345, or more than half a pack per day for every American. 11 By 1965, per capita income had risen to approximately $10,000 (in 1997 adjusted dollars). 15 Deaths from infectious diseases had fallen to Rate states have health departments First continuous municipal use of chlorine in water in United States Influenza pandemic Last human-to-human transmission of plague First use of penicillin Salk vaccine introduced Passage of Vaccination Assistance Act FIGURE 1 5 Decline in mortality due to infectious diseases in the United States, 1900 to Rate is per 100,000 population per year. (Data on chlorine use from American Water Works Association: Water chlorination principles and practices: AWWA manual M20. Denver, American Water Works Association, From Achievements in public health : Control of infectious diseases. MMWR Morbid Mortal Wkly Rep 48:621, Adapted from Armstrong GL, Conn LA, Pinner RW: Trends in infectious disease mortality in the United States during the 20 th century. JAMA 281:61, 1999.) Year fewer than 50 per 100,000 population per year, and life expectancy was up to almost 70 years.however,almost 52 percent of men and 34 percent of women were smokers, and fat consumption represented 41 percent of total calories.age-adjusted CHD mortality rates were at their peak, at approximately 225 per 100,000 people. Stroke rates were also high, at 75 per 100,000. GROWTH OF THE HEALTH CARE INDUSTRY One of the most remarkable changes in the years after World War II was the growth of the health care industry. Only some of this growth was stimulated by rises in per capita GDP. In the private sector, the growth of labor unions propelled a major expansion in private health care insurance. In fact, by the late 1950s, more than two thirds of the working U.S. population had some form of private insurance. 16 The federal government also played an important role. Increases in federal funding (the Hill Burton Act of 1948) led to the construction of more hospitals to deal with the acute manifestations of chronic illnesses. These new hospitals drew on the great successes of the military hospitals. 17 In 1966, two key federal insurance programs, Medicare and Medicaid, provided access to medical care for the medically indigent and the elderly. The Health Professions Education Assistance Act of 1966, which provided capitation grants to medical schools, doubled medical school enrollment over the next two decades through expanded class size and

7 TABLE 1 4 Cardiovascular Disease, United States, 2000 Prevalence* Crude Mortality Percentage of Rate per 100,000 Type (Millions) (Thousands) Total Deaths Population Cardiovascular disease Hypertension Ischemic heart disease Stroke Arrhythmia Congestive heart failure Rheumatic heart disease NA Valvular disease (nonrheumatic) NA Myocardial infarction 1100 New 650 Recurrent 450 Stroke 700 New 500 Recurrent 200 CABG 519 PTCA 561 Annual Events* (Thousands) Valve surgery 87 Total costs $351.8 billion Direct $204.3 billion Indirect $142.5 billion CABG = coronary artery bypass grafting; CDC, Centers for Disease Control and Prevention; NA = not available; PTCA = percutaneous transluminal coronary angioplasty. *Data from American Heart Association: 2003 Heart and Stroke Statistical Update. Dallas, TX, American Heart Association, From Miniño AM, Arias E, Kochanek KD, et al: Deaths: Final Data for National Vital statistics reports, vol 50, no 15. Hyattsville, MD, 2002, National Center for Health Statistics. establishment of new medical schools.the establishment of the National Institutes of Health, spurred largely by scientific achievements in medicine made during World War II,not only promoted health-related research but also transformed medical education by providing financial support for the establishment of full-time medical school faculty. The Age of Declining Degenerative Diseases A decline in age-adjusted CVD mortality rates began in the mid-1960s, and there have been substantial reductions in rates of mortality from both stroke and CHD since then. 18 These reductions have occurred among both whites and blacks, among men and women, and in all age groups. Ageadjusted CHD mortality rates have fallen approximately 2 percent per year, and stroke rates have fallen 3 percent per year (see Fig. 1 2). Table 1 4 gives a snapshot of CVD in 2000, the last year for which complete statistics are available. DECLINE IN CARDIOVASCULAR DISEASE MORTAL- ITY. Two main factors have been attributed to the decline in CVD mortality rates: therapeutic advances and prevention measures targeted at people with CVD and those potentially at risk for it Treatments once considered advanced, including the establishment of emergency medical systems, coronary care units, and the widespread use of new diagnostic and therapeutic technologies such as echocardiography, cardiac catheterization, angioplasty, bypass surgery, and implantation of pacemakers and defibrillators are now considered the standard of care. Advances in the pharmaceutical industry have also had a major impact on both primary and secondary prevention. Efforts to improve the acute management of myocardial infarction led to the development of life-saving drugs such as beta blockers, percutaneous coronary intervention thrombolytics, angiotensin-converting enzyme inhibitors, and others (see Chaps. 46 and 47). 22 The widespread use of an old drug, aspirin, has also reduced the risk of dying of acute or secondary coronary events. Lowcost pharmacological treatment for hypertension (see Chap. 38) and the development of highly effective cholesterollowering drugs such as statins have also made major contributions to reducing deaths from CVD in both primary and secondary prevention (see Chaps. 39 and 42). Such shifts are reflected in the burgeoning cost of medical care. In 1965, Americans spent approximately 5.9 percent of the GDP ($42 billion in unadjusted dollars) on health care. 23 In 2001, the last year for which complete statistics are available, we spent 14.1 percent of the GDP ($1.4 trillion in unadjusted dollars), or $5035 per capita. 24 In concert with these advances, public health campaigns have also hammered home the message that certain behaviors increase the risk of CVD and that life-style modifications are particularly effective ways to reduce risk. One such success is with smoking cessation. In 1955, 57 percent of men smoked cigarettes, 14 whereas today 26 percent of men smoke. Among women, the prevalence of smoking has fallen from a high of 34 percent in 1965 to 21 percent today. Campaigns beginning in the 1970s resulted in dramatic improvements in the detection and treatment of hypertension. 18 This likely had a profound and immediate effect on stroke rates and a more subtle effect on CHD rates. Similar public health messages concerning saturated fat and cholesterol are largely responsible for the decline in overall fat consumption as a percentage of total calories from approximately 45 percent in 1965 to 34 percent in and the decline in population mean cholesterol levels from 220 mg/dl in the early 1960s to 203 mg/dl in the early 1990s. 18 A main characteristic of the age of declining degenerative diseases is the steadily rising age at which a first CVD event occurs or at which people die of CVD (Fig. 1 6). Despite declines in age-adjusted mortality, the aging of the population will cause CVD to remain the predominant cause of morbidity and mortality. This, in turn, leads to everincreasing numbers of individuals with CVD as well as everincreasing health expenditures related to its treatment. In 2000, for example, CVD was the first-listed diagnosis for 6.3 million inpatients. 26 Hospital discharges included 781,000 for acute myocardial infarction; 716,000 for cardiac dysrhythmias; 999,000 for congestive heart failure; 1,221,000 for cardiac catheterizations; 519,000 for bypass surgery; 1,025,000 for percutaneous coronary interventions; and 327,000 for insertions or revision of a pacemaker or defibrillator. In addition, there were 981,000 hospital discharges for stroke. 27 At the beginning of the 21st century, the nation is fully industrialized, with only 2 percent of the population involved in farming and a per capita GDP of approximately $36,300. Life expectancy at birth is 74.1 years for men and 79.5 years for women, and at age 65 is 16.3 years for men and 19.2 for women. 28 CVD continues to be the predominant cause of morbidity and mortality, but it afflicts an older 7 Global Burden of Cardiovascular Disease

8 8 Population (%) Men Women Age (yr) FIGURE 1 6 Estimated prevalence of cardiovascular disease in Americans 20 years of age and older. (From American Heart Association: 2003 Heart and Stroke Statistical Update. Dallas, American Heart Association, 2003.) population than it did in the middle of the century. Although age-adjusted CVD rates continue to fall, the rate of decline began slowing in the 1990s, with virtually no change in stroke rates for the last 5-year period for which data are available. CHD rates may also be leveling off, owing in part to a slowing in the rate of decline in risk factors such as smoking and increases in other risk factors such as obesity and physical inactivity. Is the United States Entering a New Phase of the Epidemiological Transition? Although rates of CHD and stroke death fell 2 to 3 percent per year through the 1970s and 1980s, the rate of decline has slowed. 21 Overweight and obesity are increasing at an alarming pace, and only a minority of the population meets minimal physical activity recommendations. This has resulted in increases in diabetes and hypertension. Rates of detection and treatment of hypertension are stagnant. 29 The decline in smoking rates has leveled off, with approximately 26 percent of men and 21 percent of women classified as current smokers. 14 Even more troubling are increases in childhood obesity and physical inactivity, leading to large increases in diabetes and hypertension among younger individuals. 30,31 These troubling changes in CVD risk behaviors and factors may slow the rate of decline and could even contribute to increases in age-adjusted rates of CVD in the coming years. Current Worldwide Variations in the Global Burden of Cardiovascular Disease An epidemiological transition much like the one that occurred in the United States is occurring throughout the world. As in the United States, worldwide CVD rates have risen steadily throughout the 1900s. At the close of the 20th century, 28 percent of all deaths worldwide were due to CVD, whereas communicable diseases accounted for 34 percent of the total. 2 With the ongoing global transition, dominated by the transition in the developing world, CVD is predicted to be the number one cause of death by 2020, accounting for 36 percent of all deaths, whereas communicable diseases will account for barely half that, at 15 percent. 2 Looking behind the global transition reveals vast discrepancies in regional rates of change. These wide variations began to appear early in the 20th century. Although most of the world remained in the phase of pestilence and famine, economic circumstances in several relatively confined regions changed rapidly, accelerating the pace of their epidemiological transitions. Thus, the global burden of CVD is best understood by examining the differential rates of change in each economic region. In addition to variability in the rate of the transition, there are unique regional features that have modified aspects of the U.S.-style transition in various parts of the world. In terms of economic development, the world can be divided into two broad sectors, as described in Table 1 1: (1) the developed world, which can be further subdivided into the established market economies (EstME) and the emerging market economies (EmgME); and (2) the developing economies (DevE). Given the diversity within the DevE, it is useful to further subdivide it into six distinct economic/ geographic regions: China, India, other Asian countries and Pacific islands, sub-saharan Africa, the Middle Eastern Crescent, and Latin America and the Caribbean. Currently, four of every five people live in countries with developing economies, and it is these countries that are driving the rates of change in the global burden of CVD. Like the United States, the rest of the EstME are largely in the fourth phase of the epidemiological transition, with CVD accounting for 45 percent of all deaths in 1990 and communicable diseases accounting for well under 10 percent (see Table 1 1). The EmgME are generally in the third phase of the transition, with CVD accounting for 54 percent of deaths. In the DevE overall, 23 percent of deaths are due to CVD, whereas communicable diseases account for 42 percent of deaths. Across the six subgroups of the DevE, however, there remains a high degree of heterogeneity with respect to the phase of the epidemiological transition, as illustrated by the dominant disease rates in each region (Table 1 5). In sub-saharan Africa, communicable disease rates still far exceed those of chronic diseases, placing it in the first phase (pestilence and famine). Within regions, there is a great deal of heterogeneity. Some regions of India, for example, appear to be in the first phase, characterized by high rates of infectious and communicable disease, whereas others are in the second or even the third phase. The Middle East appears to be in the third phase of the epidemiological transition. This section briefly describes the difficulties in assessing and comparing disease rates around the world and discusses the regional rates, as well as highlights withinregion variations. Established Market Economies At the beginning of the 21st century, approximately 840 million people (13.6 percent of the world s population) live in the established market economies of the United States, Canada, Australia, New Zealand, Western Europe, and Japan. In these countries, CHD rates tend to be twofold to fivefold higher than stroke rates. Table 1 6 demonstrates this tendency in selected European countries. There are two notable exceptions. In Portugal, stroke rates for both men and women are higher than CHD rates. The same is true for Japan, where stroke is responsible for far more fatalities than CHD. Rapid declines in CHD and stroke rates since the early 1970s signal that the EstME countries are in the fourth phase of the epidemiological transition, the age of delayed degenerative diseases. In general, stroke rates have fallen faster than CHD rates, increasing the CHD-to-stroke ratio. In the United States, for example, stroke rates over the past three decades have fallen an average of 3 percent per year, whereas CHD rates have fallen approximately 2 percent per year. The rates of CVD in Western Europe tend to be similar to those in the United States. However, the absolute rates vary threefold among the countries of Western Europe with a clear north/south gradient, with higher CHD and stroke rates in the

9 TABLE 1 5 Mortality and Disability-Adjusted Life Years Lost by Disease Category in the Developing World Region China India Other Asia SSA MEC LatAm Total 9 Deaths (%) CMPN Injury Non-CVD, non-cmpn All CVD Ischemic heart disease Stroke Rheumatic heart disease Other CVD Disability-adjusted life-years (%) CMPN Injury Non-CVD, non-cmpn All CVD Ischemic heart disease Stroke Rheumatic heart disease CMPN = communicable, maternal, perinatal, and nutritional diseases; CVD = cardiovascular disease; LatAm = Latin America; MEC = Middle Eastern Crescent; SSA = sub-saharan Africa. Adapted from Murray CJL, Lopez AD: The Global Burden of Disease. Cambridge, MA, Harvard School of Public Health, Global Burden of Cardiovascular Disease TABLE 1 6 Age-Adjusted, All-Cause and Cardiovascular Mortality in European Countries, * Country All Causes CVD CHD Stroke Established market economies Spain Men Women France Men Women Portugal Men Women Finland Men Women Scotland Men Women Economies in transition Russian Federation Men Women Ukraine Men Women CHD = coronary heart disease; CVD = cardiovascular disease. *Per 100,000 men and women aged years. From World Heart Federation: Impending Global Pandemic of Cardiovascular Diseases. Barcelona, Prous Science, north. The highest CVD rates in the European established market economies (two to three times higher than the median rates) are in Finland, Northern Ireland, and Scotland, where CVD-related mortality exceeds 800 deaths per 100,000 for men and 500 deaths per 100,000 for women. 32 The lowest CVD rates are in the Mediterranean countries of Spain and France, where annual CVD rates are less than 400 and 200 per 100,000 for men and women, respectively. Although both stroke and CHD rates are higher in northern Europe, the disparity in CHD rates is much greater. For example, male CHD rates are 362 percent higher in Finland than in Spain, whereas stroke rates are only 49 percent higher. 32 CVD rates in Canada, New Zealand, and Australia are similar to rates in the United States. JAPAN. This country is unique among the EstME. As its rates of communicable disease fell in the early part of the 20th century, stroke rates increased dramatically; and by the middle of the century they were the highest in the world. CHD rates, however, did not rise as sharply as they did in other industrialized nations and have remained lower than in any other industrialized country. Overall CVD rates have fallen 60 percent since the 1960s, largely due to a decrease in age-adjusted stroke rates. Japanese men and women currently have the highest life expectancies in the world: 84.7 years for women and 77.9 years for men. 1 The difference between Japan and other industrialized countries may stem in part from genetic factors, but it is more likely that the average plant-based, low-fat diet and resultant low cholesterol levels have played a more important role. As is true for so many countries, Japanese dietary habits are undergoing substantial changes. In the last half of the 20th century, there was an estimated 9.3-fold increase in annual per capita consumption of meat, a 5.2-fold increase in egg consumption, a 7.4-fold increase in milk and dairy consumption, and a 5.3- fold increase in consumption of fats and oils. 33 These changes may explain possible recent increases in CHD.