EPA's Report on the Environment
Chronic Obstructive Pulmonary Disease Prevalence and Mortality
Chronic obstructive pulmonary disease (COPD), sometimes referred to as chronic lung disease, is a disease that damages lung tissue or restricts airflow through the large and small airways leading to the air sacs in the lungs. Chronic bronchitis and emphysema are the most frequently occurring COPDs. Smoking is the most common risk factor for developing COPD, including cigarette, pipe, and cigar smoking (NHLBI, 2013). Other risk factors in the development and progression of COPD include asthma, exposure to air pollutants in the ambient air and workplace environment, genetic factors, and respiratory infections (CDC, 2011).
Environmental tobacco smoke (
This indicator presents U.S. adult (age 18 and older) prevalence rates for chronic bronchitis and emphysema and U.S. adult (age 25 and older) death rates for COPD as a whole and for chronic bronchitis and emphysema. Age-adjusted COPD prevalence data were compiled from 2002 to 2014 from the National Health Interview Survey (NHIS), conducted by the Centers for Disease Control and Prevention’s (CDC’s) National Center for Health Statistics (NCHS). The NHIS is the principal source of information on the health of the civilian non-institutionalized population of the U.S. and since 1960 has been one of the major data collection programs of NCHS. COPD prevalence is based on the number of adults who reported that they had ever been told by a doctor or other health practitioner that they had emphysema or if a health practitioner told them they had chronic bronchitis in the last 12 months. Mortality data (age 25 and older) were compiled between 1979 and 2014 using the National Vital Statistics System (NVSS), maintained by NCHS. Because of the change of reporting requirements for race and ethnicity, data by demographic group (i.e., sex, race, ethnicity, and age group) were compiled for the years 1999 to 2014, when data are available to compare more races and ethnicities. The NVSS registers virtually all deaths and births nationwide, with data coverage from 1933 to 2014 and from all 50 states and the District of Columbia. Data were queried and compared separately for years 1979-1998 and those 1999 onward because the NVSS uses different codes to specify causes of death for these two time periods: the International Classification of Diseases 9th Revision (ICD-9) codes for 1979-1998 and the International Classification of Diseases 10th Revision (ICD-10 codes) beginning in 1999.
What the Data Show
Exhibits 1 and 2 present the age-adjusted prevalence of chronic bronchitis and emphysema from 2002 to 2014, respectively. The reported total prevalence of chronic bronchitis in U.S. adults over the age of 18 years has generally decreased during this time period, ranging from 44 cases per 1,000 (2002) to 35 cases per 1,000 in 2014. The reported prevalence of emphysema in U.S. adults during the same time period fluctuated up and down, with the highest rate of 21 cases per 1,000 in 2009 and the lowest in 2014 (13 cases per 1,000).
Exhibits 1 and 2 also display age-adjusted chronic bronchitis and emphysema prevalence in U.S. adults, respectively, by race, ethnicity, and sex; age-specific prevalence is also presented. For the 13 years shown for chronic bronchitis, whites have the highest prevalence in four years and American Indians/Alaska Natives have the highest prevalence in nine years. Asians have the lowest prevalence of chronic bronchitis in all 13 years reported (Exhibit 1). For nine of the 13 years reported, emphysema prevalence is highest among white adults. American Indians/Alaska Natives have the highest prevalence for four of the 13 years reported. Asians consistently have the lowest prevalence of emphysema except in 2006, when the prevalence for Asians is above that of blacks (Exhibit 2). Prevalence of both bronchitis and emphysema rises with age, with the highest rates seen among those 65 and older.
The Hispanic or Latino population had a consistently lower prevalence of chronic bronchitis (Exhibit 1) and emphysema (Exhibit 2) than the non-Hispanic or Latino population from 2002 to 2014, the period for which these data are available. For example, in 2014, prevalence in Hispanics or Latinos was lower than non-Hispanics or Latinos for chronic bronchitis (19 compared to 38 cases per 1,000, respectively) and emphysema (9 compared to 13 cases per 1,000, respectively). Prevalence also differs by sex. In 2014, females had more than 1.7 times the reported prevalence of chronic bronchitis compared to males (44 versus 26 cases per 1,000, respectively), a consistently observed difference between 2002 and 2014 (Exhibit 1). In contrast, the prevalence rates for emphysema from 2002 to 2010 were consistently higher in males than in females, with the difference varying by as much as 12 cases per 1,000 (2006) and as little as 1 case per 1,000 (2008). In 2011, however, prevalence for emphysema was the same in females and in males (19 cases per 1,000). From 2012 to 2014, emphysema prevalence reverted back to the earlier pattern of males having higher rates compared to females (Exhibit 2).
In 2014, chronic lower respiratory disease, primarily COPD, was the third leading cause of mortality in the United States (CDC, 2015; NCHS, 2016). Specifically, in 2014, COPD accounted for 143,379 (5.6 percent) of all deaths among adults aged 25 years and older (CDC, 2015). Exhibit 3 shows that the age-adjusted death rate for COPD as a whole has increased over time, with national rates ranging from 37.4 per 100,000 in 1979 to 61.4 per 100,000 in 1998. From 1999 to 2014, rates held steadier, ranging from a high of 67.6 per 100,000 in 1999 to a low of 60.9 per 100,000 in 2014.
Age-adjusted death rates for emphysema (range of 9.5-10.9 per 100,000 for 1979-1998, and 3.2-10.0 per 100,000 for 1999-2014) and chronic bronchitis (range of 1.4-2.6 per 100,000 for 1979-1998 and 0.1-0.3 per 100,000 for 1999-2014) appear to be slowly declining or steady. It is noteworthy that in 2014 approximately 78 percent of all COPD mortality is of an unspecified nature and not attributed to a specific COPD subgroup such as emphysema or chronic bronchitis (CDC, 2015). (Data not shown.)
Exhibit 3 presents the overall COPD death rates in the U.S. and the 10 EPA Regions for 1979-1998 and 1999-2014. The age-adjusted COPD death rates increased in each of the 10 Regions between 1979 and 1998. The rates ranged from 32.2 (Region 2) to 45.8 (Region 8) per 100,000 in 1979 and 48.8 (Region 2) to 70.6 (Region 8) per 100,000 in 2014. Between 1999 and 2014, COPD death rates in each of the 10 EPA Regions have shown an overall decline or remained steady, except for Region 7 that had a slight increase over this time period.
Exhibit 4 presents age-adjusted COPD death rates from 1999 to 2014 among U.S. adults aged 25 years and older by sex, race, ethnicity, and age group. As shown, COPD age-adjusted death rates have been declining for males over time, with a rate of 88.6 per 100,000 in 1999 compared to 68.7 per 100,000 in 2014. For females, the rates are lower than males and have been relatively stable between 1999 and 2014 (55.2 and 55.5 per 100,000, respectively). Rates declined among the races shown, with the highest age-adjusted death rates consistently observed among whites (ranging from 71.5 per 100,000 in 2008 to 65.2 per 100,000 in 2006) and the lowest rates observed among Asians or Pacific Islanders (ranging from 26.4 per 100,000 in 1999 to 18.0 per 100,000 in 2014). Rates also declined by ethnicity, with a range of 33.3 per 100,000 in 1999 to 25.8 per 100,000 in 2014 among the Hispanic or Latino population. Rates for those not Hispanic or Latino are higher, but still declined from 1999 (69.2 per 100,000) to 2014 (63.8 per 100,000). COPD death rates also vary by age, with higher rates observed among older age groups. For example, the 2014 rates were 0.6 per 100,000 for those aged 25-44 years, 20.9 per 100,000 for those aged 45-64 years, and 273.3 per 100,000 for those aged 65 years and older.
- Prevalence data presented in the NHIS are based on self-reported responses to specific questions pertaining to COPD-related illnesses, and are subject to the biases associated with self-reported data. Self-reported data can underestimate the disease prevalence being measured if, for whatever reason, the respondent is not fully aware of his/her condition.
COPD death rates are based on underlying cause of death as entered on a death certificate by a physician. Some individuals may have had competing causes of death. “When more than one cause or condition is entered by the physician, 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, 2016). Consequently, some misclassification of reported mortality might occur in individuals with competing causes of death, as well as the possible underreporting of COPD as the cause of death.
- The International Classification of Diseases 9th Revision (ICD-9) codes were used to specify underlying cause of death for years 1979-1998. Beginning in 1999, cause of death is specified with the International Classification of Diseases 10th Revision (ICD-10) codes. The two revisions differ substantially, and to prevent confusion about the significance of any specific disease code, data queries are separate.
COPD prevalence data were obtained from annual reports and standalone tables published by NCHS (NCHS, 2004, 2005, 2006a,b, 2007, 2009a,b, 2010, 2012a,b, 2014, 2015a,b), which summarize health statistics compiled from the NHIS (https://www.cdc.gov/nchs/nhis/nhis_series.htm). Mortality statistics were obtained from CDC’s “compressed mortality” database, accessed through CDC WONDER (CDC, 2015) (https://wonder.cdc.gov/mortSQL.html). EPA Regional mortality statistics were generated by combining and age-adjusting state-by-state totals for each EPA Region using data from CDC WONDER.
For More Information
- CDC National Health Interview Survey
- CDC Mortality Data (National Vital Statistics System)
- CDC Chronic Obstructive Pulmonary Disease (COPD) Information
- Learn how this indicator fits into a conceptual diagram for: Tropospheric Ozone
- This indicator relates to the ROE question on Disease and Conditions
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