General Mortality

Overall mortality is a key measure of health in a population. Three measures of mortality are “all cause” mortality, cause-specific mortality, and years of potential life lost (YPLL). “All cause” mortality counts the total number of deaths due to any cause within a specified year, whereas cause-specific mortality statistics count the number of deaths due to a particular cause in a specified year. YPLL is defined as the number of years between the age at death and a specified age; that is, the total number years “lost” by persons in the population who die prematurely of a stated cause. Ranking the causes of death can provide a description of the relative burden of cause-specific mortality (NCHS, 2005).

This indicator is based on mortality data recorded in the National Vital Statistics System, which registers virtually all deaths nationwide from death certificate data. YPLL is calculated by subtracting the age at death from a selected age (e.g., 65, 75, 85), then summing the individual YPLLs across each cause of death (CDC, 2015a). Sixty-five was selected as the age for this indicator to focus on deaths more likely to be attributable to preventable causes and less influenced by increasing age. The temporal coverage of the data is from 1940 to 2013 and data are collected from all 50 states and the District of Columbia.

An increase in the number of deaths in the U.S. has been observed over the last few decades, reflecting the increase in the size and aging of the population. However, the age-adjusted all cause death rates have declined yearly since 1980 (except in years of influenza outbreaks in 1983, 1985, 1988, 1993, and 1999; a slight increase in 2005; and a slight increase among whites, non-Hispanics, and non-Hispanic whites from 2012 to 2013) with the most recent available rate of 731.9 deaths per 100,000 people in 2013. Exhibit 1 provides some historical perspective on trends in the age-adjusted death rates between 1940 and 2013, showing that age-adjusted rates were more than twice as high in 1940 as they were in 2013. Also since 1940, age-adjusted rates have decreased by 61 percent for females compared to 56 percent for males. Across all races and ethnicities reported since 1997, the largest decline in “all cause” death rates has occurred among Blacks.

Exhibits 2 and 3 present the leading causes of mortality and YPLL for 2013, respectively. The three leading causes of death in rank order for all races and both sexes were heart disease, cancer (malignant neoplasms), and chronic lower respiratory diseases, accounting for 52 percent of all deaths (Exhibit 2). The rank order of the leading causes of death has remained generally the same since 1999. In 2008, however, some shifts—which remained unchanged from 2009 through 2013—were observed: Chronic lower respiratory diseases replaced stroke as the third leading cause of death, and suicide replaced septicemia as the tenth leading cause of death, accounting for about 1.6 percent of all deaths in the United States in 2013. The YPLL ranking is different for all races and both sexes, with accidents (unintentional injuries), cancer (malignant neoplasms), and heart disease as the first, second, and third leading causes, respectively (Exhibit 3).

During 2013, heart disease was the leading cause of death across the reported racial and ethnic groups, except for Asians or Pacific Islanders and Hispanics, for whom cancer (malignant neoplasms) was the leading cause of death. Heart disease, cancer (malignant neoplasms), and accidents (unintentional injuries) are in the top five causes of death for all reported racial and ethnic groups. Diabetes continues to rank in the top five causes of death among American Indians/Alaska Natives, Asians or Pacific Islanders, Blacks, and Hispanics, and ranks seventh among Whites and non-Hispanics behind Alzheimer’s Disease (Exhibit 2).

Also in 2013, cancer (malignant neoplasms) was the first or second leading cause of YPLL across all of the reported racial and ethnic groups except for American Indians/Alaska Natives. Accidents (unintentional injuries) and heart disease were in the top five causes of YPLL for all reported racial and ethnic groups. Perinatal period ranks in the top five causes of YPLL among Asians or Pacific Islanders, Blacks, non-Hispanics, Hispanics, and Whites, and ranks seventh among American Indians/Alaska Natives (Exhibit 3).

• Cause of death rankings denote the most frequently occurring causes of death among those causes eligible to be ranked. The rankings do not necessarily denote the causes of death of greatest public health importance. Further, rankings of cause-specific mortality could change depending on the defined list of causes that are considered and, more specifically, the types of categories and subcategories that are used for such rankings (NCHS, 2005).
• Death rates are based on underlying cause of death as entered on a death certificate by a physician, medical examiner, or coroner. Incorrect coding and low rates of autopsies that confirm the cause of death may occur. Additionally, some individuals may have had competing causes of death. When more than one cause or condition is entered by the physician, medical examiner, or coroner, the underlying cause is determined by the sequence of conditions on the certificate, provisions of the ICD [International Classification of Diseases], and associated selection rules and modifications (CDC, 2015b). Consequently, some misclassification of reported mortality might occur as a result of these uncertainties, as well as the underreporting of some causes of death.

Death rates were obtained from vital statistics reports published by CDC’s National Center for Health Statistics (NCHS, 2001, 2015). Data in the NCHS reports are based in part on unpublished work tables, available on the NCHS website at http://www.cdc.gov/nchs/deaths.htm. Leading cause of death and YPLL data were extracted from CDC’s Web-Based Injury Statistics Query and Reporting System (WISQARS) (CDC, 2015a) (http://www.cdc.gov/injury/wisqars/). The underlying data in WISQARS come from CDC/NCHS annual mortality data files.