Health Status of the United States

There are several ways to assess the health of a specific group of people or an entire country's population that are used consistently across the world as indicators of health status. They include how long people can expect to live (life expectancy), how many infants die before their first birthday (infant mortality), the major causes of death, and the amount of illness in a national population. Among the most common measurements is the number of deaths caused by disease. The national death rate for a disease—especially if the numbers of early deaths (deaths before the average life expectancy) are high—can be a warning of health problems. This section presents an overview of health and major disease trends in the U.S. Some important diseases are presented that have a major impact on the health of Americans. It is important to note that environmental factors may not play a role in all diseases or causes of death presented in this section.

What are the trends and indicators for health and disease in the United States?

The overall health status of the U.S. today is generally good and improving. Over the past century, the nation has basically conquered many infectious diseases that once sickened or killed thousands of people: childhood diseases such as measles and mumps, and waterborne ailments such as typhoid and cholera. Significant progress in improving sanitation and drinking water means that Americans are now relatively safe from the diarrheal diseases that imperil much of the world. Accidents are now the leading threat to children in the U.S., and most adults die from chronic illnesses rather than from infectious diseases (Exhibit 4-1). At the turn of the century, many people died from infectious diseases such as tuberculosis and influenza. Today more than 60 percent of all U.S. deaths are attributed to cardiovascular diseases—those involving the heart and blood vessels—and cancer.¹

Infant mortality (death) and life expectancy are two key indicators of any nation's overall health (Exhibit 4-2). Infant mortality has dropped to the lowest level ever recorded in the U.S.,² but U.S. rates are still higher than those of other developed countries. In 1998, the U.S. ranked 28th out of 38 countries with available statistics for infant mortality.³

American life expectancy continues to improve. In the last century, life expectancy at birth increased from 51 to 79.4 years for women and from 48 to 73.9 years for men.⁴ However, Americans still have a somewhat lower life expectancy than those of other developed countries.⁵ In 1997, the U.S. ranked 19th for both males and females in life expectancy, compared with 30 other countries or geographic areas of at least 1 million people. (The U.S. numbers are within 2 years of the life expectancy of 13 and 14 other countries for females and males, respectively.)⁶

Because many infectious diseases are controlled and Americans are living longer, it is not surprising that chronic health problems, which are often associated with aging (e.g., heart disease, cancer, stroke, and lung disease), are among the leading causes of illness and death. Some conditions are wholly or partly the result of individual choices about smoking, diet, or exercise, but other health problems may also be associated with exposure to environmental pollutants.

Exhibit 4-1: Causes of death, United States, 1900 and 1998.
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Exhibit 4-2: Life expectancy and infant mortality in the US.
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The trend data for the diseases presented in this section provide a valuable national overview of the U.S. population. Exhibit 4-3 summarizes the national trends for death rate (number of people dying per year), and incidence rate (number of people developing the disease per year) or prevalence (part of the population affected by a condition or disease). Exhibit 4-4 shows trends in death rates for people age 65 and older.

Exhibit 4-3: Select disease trends
Exhibit 4-4: US death rates due to leading causes of death among persons 65 years of age and older, 1950-1999
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Cancer

National cancer death rates declined overall during the 1990s,⁷ but cancer is still the second-leading cause of death in the U.S., and the number of people who develop cancer each year has actually increased since 1973.⁸ Although the overall death rates have dropped for some types—leukemia and breast, cervical, colorectal, stomach, and uterine cancers—the death rates for lung cancer and skin cancer, the most common type of cancer in the country, have increased.⁹ The number of people developing cancer shows the same mixed results for different subsets of the U.S. population. For example, lung cancer rates have declined for men but increased for women since 1973, and leukemia rates have declined among adults but not among children.¹⁰

Cardiovascular Disease

Cardiovascular diseases (CVD) are any that involve the heart and blood vessels. Examples are high blood pressure and hardening of the arteries, which can lead to heart attacks, strokes, and disability. Until age 65, more men than women have CVD, but after that age, the percentages are the same for women and men. After age 74, a higher percentage of women than men have CVD. The overall mortality trend for CVD has declined dramatically since the 1950s (Exhibit 4-4). Advances in the prevention and treatment of heart disease and stroke rank among the major public health achievements of the 20th century.¹¹ Heart disease remains the leading cause of death in the U.S., and stroke is third.

Respiratory and Lung Diseases

Chronic obstructive pulmonary disease (COPD) encompasses a group of health conditions such as obstructed airflow and breathing-related symptoms. Chronic bronchitis and emphysema, for example, are classified as COPD. In 1999, COPD was the fourth-leading cause of death in the U.S.¹² Between 1980 and 1998, death rates for COPD increased for all racial and ethnic groups in the nation, reflecting in large part the effects of cigarette smoke.^13,14 Death rates for males began to decline slightly between 1993 and 1998; by contrast, death rates for females have steadily increased since 1980.¹⁵ Mortality data may not give a complete picture of the environmental impact of the disease, because many people with COPD have progressive disability, not immediate death.

Asthma

Asthma is a disorder of the respiratory system characterized by labored breathing, wheezing, cough, and pain or tightness in the chest. It is a common chronic disease in children, and in adults it is more common in females and African Americans. Although the number of adults with asthma has declined slightly since 1997, childhood asthma is on the rise.¹⁶ Asthma death rates for adults have also increased since 1980. The groups that have the highest incidence, women and African Americans, also have the highest death rates.¹⁷ The prevalence of asthma shows regional differences; it is highest in the Northeast and lowest in the South. In addition, in a 1996 survey, people who lived in a central city reported a higher percentage of asthma cases than those who lived elsewhere.¹⁸ Asthma is believed to have a genetic component, but airborne allergens and irritants in the home, workplace, and community can aggravate the disease and trigger attacks.