Cardiovascular disease (CVD) is now the most common cause of death worldwide. Before 1900, infectious diseases and malnutrition were the most common causes and CVD was responsible for less than 10% of all deaths. Today, CVD accounts for approximately 30% of deaths worldwide, including nearly 40% in high-income countries and about 28% in low- and middle-income countries.
The global rise in CVD is the result of an unprecedented transformation in the causes of morbidity and mortality during the twentieth and twenty-first centuries. Known as the epidemiologic transition, this shift is driven by industrialization, urbanization, and associated lifestyle changes and is taking place in every part of the world among all races, ethnic groups, and cultures. The transition is divided into four basic stages: pestilence and famine, receding pandemics, degenerative and human-made diseases, and delayed degenerative diseases. A fifth stage, characterized by an epidemic of inactivity and obesity, may be emerging in some countries (Table 225-1).
Table 225–1. Five Stages of the Epidemiologic Transition
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Table 225–1. Five Stages of the Epidemiologic Transition
|Stage||Description||Deaths Related to CVD, %||Predominant CVD Type|
|Pestilence and famine||Predominance of malnutrition and infectious diseases as causes of death; high rates of infant and child mortality; low mean life expectancy||<10||Rheumatic heart disease, cardiomopathies caused by infection and malnutrition|
|Receding pandemics||Improvements in nutrition and public health lead to decrease in rates of deaths related to malnutrition and infection; precipitous decline in infant and child mortality rates||10–35||Rheumatic valvular disease, hypertension, CHD, and stroke (predominantly hemorrhagic)|
|Degenerative and human-made diseases||Increased fat and caloric intake and decrease in physical activity lead to emergence of hypertension and atherosclerosis; with increase in life expectancy, mortality from chronic, noncommunicable diseases exceeds mortality from malnutrition and infectious disease||35–65||CHD and stroke (ischemic and hemorrhagic)|
|Delayed degenerative diseases||CVD and cancer are the major causes of morbidity and mortality; better treatment and prevention efforts help avoid deaths among those with disease and delay primary events; age-adjusted CVD morality rate declines; CVD affecting older and older individuals||40–50||CHD, stroke, and congestive heart failure|
|Inactivity and obesity||Overweight and obesity increase at alarming rate; diabetes and hypertension increase; decline in smoking rates levels off; a minority of the population meets physical activity recommendations||Possible reversal of age-adjusted declines in mortality||CHD, stroke, and congestive heart failure, peripheral vascular disease|
Malnutrition, infectious diseases, and high infant and child mortality rates that are offset by high fertility mark the age of pestilence and famine. Tuberculosis, dysentery, cholera, and influenza are often fatal, resulting in a mean life expectancy of about 30 years. Cardiovascular disease, which accounts for less than 10% of deaths, takes the form of rheumatic heart disease and cardiomyopathies due to infection and malnutrition. Approximately 10% of the world's population remains in the age of pestilence and famine.
Per capita income and life expectancy increase during the age of receding pandemics as the emergence of public health systems, cleaner water supplies, and improved nutrition combine to drive down deaths from infectious disease and malnutrition. Infant and childhood mortality rates also decline, but deaths due to CVD increase to between 10% and 35% of all deaths. Rheumatic valvular disease, hypertension, coronary heart disease, and stroke are the predominant forms of CVD. Almost 40% of the world's population is currently in this stage.
The age of degenerative and human-made diseases is distinguished by mortality from noncommunicable diseases—primarily CVD—surpassing mortality from malnutrition and infectious diseases. Caloric intake, particularly from animal fat, increases. Coronary heart disease and stroke are prevalent, and 35%–65% of all deaths can be traced to CVD. Typically, the rate of CHD deaths exceeds that of stroke by a ratio of 2:1 to 3:1. During this period, average life expectancy surpasses 50 years. Roughly 35% of the world's population falls into this category.
In the age of delayed degenerative diseases, CVD and cancer remain the major causes of morbidity and mortality, with CVD accounting for 40% of all deaths. However, age-adjusted CVD mortality declines, aided by preventive strategies such as smoking cessation programs and effective blood pressure control, acute hospital management, and technological advances such as the availability of bypass surgery. Coronary heart disease (CHD), stroke, and congestive heart failure are the primary forms of CVD. About 15% of the world's population is now in the age of delayed degenerative diseases or is exiting this age and moving into the fifth stage of the epidemiologic transition.
In the industrialized world, physical activity continues to decline while total caloric intake increases. The resulting epidemic of overweight and obesity may signal the start of the age of inactivity and obesity. Rates of Type 2 diabetes mellitus, hypertension, and lipid abnormalities are on the rise, trends that are particularly evident in children. If these risk factor trends continue, age-adjusted CVD mortality rates could increase in the coming years.
The Epidemiologic Transition in the United States
The United States, like other high-income countries, has proceeded through four stages of the epidemiologic transition. Recent trends, however, suggest that the rates of decline of some chronic and degenerative diseases have slowed. Because of the large amount of available data, the United States serves as a useful reference point for comparisons.
The Age of Pestilence and Famine (before 1900)
The American colonies were born into pestilence and famine, with half the Pilgrims who arrived in 1620 dying of infection and malnutrition by the following spring. At the end of the 1800s, the U.S. economy was still largely agrarian, with more than 60% of the population living in ...