EPA's Report on the Environment: External Review Draft
Chronic Obstructive Pulmonary Disease Prevalence and Mortality
Note to reviewers of this draft revised ROE: This indicator reflects data through 2010 (Exhibits 1 and 2) and 2009 (Exhibit 3). EPA anticipates updating this indicator in 2014.
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 cause of COPD, including cigarette, pipe, and cigar smoking (NHLBI, 2003). 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 death rates for COPD as a whole and for chronic bronchitis and emphysema. COPD prevalence data were compiled from 1999 to 2010 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 (all ages) were compiled between 1979 and 2009 using the National Vital Statistics System (NVSS), maintained by NCHS. The NVSS registers virtually all deaths and births nationwide, with data coverage from 1933 to 2009 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 prevalence of chronic bronchitis and emphysema from 1999 to 2010, respectively. The reported total prevalence of chronic bronchitis in U.S. adults over the age of 18 years ranged from a high of 55 (2001) cases per 1,000 to a low of 34 (2007). The prevalence of chronic bronchitis appears to have peaked in 2001, followed by a subsequent decline from 2001 to 2007. In 2008 and 2009, however, there was an increase in the prevalence of chronic bronchitis (44 cases per 1,000) compared to 2007. Chronic bronchitis prevalence in 2010, the most current reporting year, remained similar to 2008 and 2009 (43 cases per 1,000). The reported prevalence of emphysema in U.S. adults during the same time period ranged from 14 (1999) to 22 (2009) cases per 1,000. Although the prevalence of emphysema has remained relatively stable over time, a small increase was evident during 2009, followed by a small decrease in 2010 (19 cases per 1,000), the most current reporting year.
Exhibits 1 and 2 also display chronic bronchitis and emphysema prevalence in U.S. adults, respectively, by race, ethnicity, and sex. For the 12 years reported for chronic bronchitis, whites have the highest prevalence in six years, American Indians/Alaska Natives have the highest prevalence in five years, and blacks have the highest prevalence in one year. Asians have the lowest prevalence of chronic bronchitis in all 12 years reported (Exhibit 1). For 10 of the 12 years reported, emphysema prevalence is higher among white adults. American Indians/Alaska Natives have the highest prevalence for 1 of the 12 years reported, and have the same prevalence as whites for one year. Asians consistently have the lowest prevalence of emphysema except in 2006, when the prevalence for Asians is the same as for blacks (Exhibit 2).
In addition, 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 1999-2010, the period for which these data are available. For example, in 2010, prevalence in Hispanics or Latinos was lower than non-Hispanics or Latinos for chronic bronchitis (27 compared to 46 cases per 1,000, respectively) and emphysema (7 compared to 21 cases per 1,000, respectively). Gender differences are also seen. In 2010, females had nearly twice the reported prevalence of chronic bronchitis compared to males (55 versus 31 cases per 1,000, respectively), a consistently observed difference between 1999 and 2010 (Exhibit 1). In contrast, the prevalence rates for emphysema from 1999-2007 have been consistently higher in males than in females, with the difference varying by as much as 9 cases per 1,000 (2006) and as little as 3 cases per 1,000 (2004). In 2008, however, prevalence for emphysema was slightly higher in females than in males (17 compared to 16 cases per 1,000, respectively). In 2009 and 2010, emphysema prevalence reverted back to the typical pattern during the 12-year reporting period of males having higher rates compared to females (Exhibit 2).
In 2009, COPD is the third leading cause of mortality, accounting for 137,353 (5.6 percent) of all deaths (General Mortality indicator). Exhibit 3 shows that the age-adjusted death rate for COPD as a whole has increased over time, with national rates ranging from 25.5 per 100,000 in 1979 to 41.8 per 100,000 in 1998. From 1999 to 2009, rates held steadier, ranging from a high of 45.4 per 100,000 in 1999 to a low of 40.4 per 100,000 in 2006.
Age-adjusted death rates for emphysema (range of 6.5-6.9 per 100,000 for 1979-1998, and 3.4-6.5 per 100,000 for 1999-2009) and chronic bronchitis (range of 0.9-1.7 per 100,000 for 1979-1998 and 0.1-0.2 per 100,000 for 1999-2009) appear to be slowly declining or steady. It is noteworthy that in 2009 approximately 68 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, 2012). (Data not shown.)
Exhibit 3 presents the overall COPD death rates in the U.S. and the 10 EPA Regions for 1979-1998 and 1999-2009. The age-adjusted COPD death rates increased in each of the 10 Regions between 1979 to 1998. The rates ranged from 22.2 (Region 2) to 31.2 (Region 8) per 100,000 in 1979 and 33.5 (Region 2) to 47.9 (Region 8) per 100,000 in 1998. Between 1999 and 2009, COPD death rates in each of the 10 EPA Regions have shown an overall decline. In 2005 and 2008, however, all EPA Regions (except for Region 8 in 2005) exhibited a slight increase in COPD mortality compared to the preceding year.
COPD age-adjusted death rates have been declining for males over time, with a rate of 58.7 per 100,000 in 1999 compared to 49.4 per 100,000 in 2009. For females, the rates are lower than males and have been relatively stable between 1999 and 2009 (37.7 and 37.8 per 100,000, respectively). In 2009, the COPD age-adjusted death rate was highest among whites (44.7 per 100,000), followed by blacks (29.2 per 100,000), American Indians or Alaska Natives (28.7 per 100,000), and lowest among Asian or Pacific Islanders (13.5 per 100,000). COPD death rates increase with age: the 2009 age-adjusted death rates were 0.3 per 100,000 for those aged 0-14 years, 1.0 per 100,000 for those aged 15-44 years, 22.3 per 100,000 for those aged 45-64 years, and 291.1 per 100,000 for those aged 65 years and older (CDC, 2012). (Data not shown.)
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.
All prevalence data are based on crude rates and are not age-adjusted, as CDC did not report age-adjusted data prior to 2002 in the data sources used for this indicator. Because the possible influence of subgroup age structure has not been removed, the reported disease prevalence rates across time or within different race and gender subgroups may reflect differences in the age distribution of the populations being compared.
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, n.d.). 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 published by NCHS (NCHS, 2001-2005, 2006a,b, 2007, 2009a,b, 2010, 2012), which summarize health statistics compiled from the NHIS (http://www.cdc.gov/nchs/nhis/nhis_series.htm). Mortality statistics were obtained from CDC’s “compressed mortality” database, accessed through CDC WONDER (CDC, 2012) (http://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: Disease and Conditions
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