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Asthma Prevalence

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  • Learn more about how to use this interactive exhibit
  • Save the complete indicator as a printer-friendly PDF
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  • Display statistical information for this exhibit

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  • Introduction
    • Asthma is a chronic respiratory disease characterized by inflammation of the airways and lungs. During an asthma attack, the small airways leading to the air sacs in the lungs are constricted and inflamed, and as a result, less air is able to flow out of the lungs. Asthma attacks can cause a multitude of symptoms ranging in severity from mild to life-threatening. These symptoms include wheezing, breathlessness, chest tightness, and coughing. Currently, there is no cure for asthma; however, people who have asthma can still lead productive lives if they control their asthma (NHLBI, n.d.). Taking medication and avoiding contact with environmental "triggers" can help control asthma (AAAAI, n.d.).

      A family history of asthma contributes to susceptibility, but mostly what causes the development of asthma is unknown. Environmental exposures such as environmental tobacco smoke, dust mites, cockroach allergen, outdoor air pollution (e.g., ozone, particulate matter), pets, and mold are considered important triggers of an asthma attack (CDC, 2017; Kanchongkittiphon et al., 2015; Matsui et al., 2016; U.S. EPA, 2009, 2013).

      Statistics for period asthma prevalence, current asthma prevalence, and asthma attack prevalence are based on national estimates 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. Period asthma prevalence (pre-1997 data) represents survey participants who had asthma in the past 12 months. To determine current asthma prevalence, adults/children who had ever received an asthma diagnosis from a healthcare practitioner were asked whether they still have asthma. Asthma attack prevalence is based on the number of adults/children with an asthma diagnosis who reported an asthma episode or attack in the past 12 months.

  • What the Data Show
    • Adult Asthma

      In 2016, over 20 million adults within the U.S. (age 18+ years) were reported as still having asthma (NCHS, 2018a) and nearly 10 million reported experiencing an asthma episode or attack during the previous 12 months (NCHS, 2017a; data not shown).

      As shown in Exhibit 1, between 2002 and 2016 current asthma prevalence has ranged from approximately 64 cases per 1,000 (2003) to 83 cases per 1,000 (2016). During this same time period, asthma attack prevalence has varied slightly, from a low of 33 cases per 1,000 occurring in 2003 to a high of 42 cases per 1,000 occurring in 2010.

      Exhibit 2 compares age-adjusted asthma prevalence across racial and ethnic groups for the 2014-2016 time period. American Indians/Alaska Natives reported the highest current asthma prevalence across racial groups (98 cases per 1,000), followed by blacks (92 cases per 1,000), whites (76 cases per 1,000), and Asians (48 cases per 1,000). American Indians/Alaska Natives also reported the highest asthma attack prevalence (43 cases per 1,000), followed by blacks (41 cases per 1,000), whites (36 cases per 1,000), and Asians (19 cases per 1,000).

      Exhibit 2 also compares both asthma prevalence categories for total Hispanics, non-Hispanic whites, and non-Hispanic blacks. For current asthma prevalence in adults, there were 60 cases per 1,000 for total Hispanics, 81 cases per 1,000 for non-Hispanic whites, and 92 cases per 1,000 for non-Hispanic blacks. For asthma attack prevalence in adults, there were 29 cases per 1,000 for total Hispanics, 38 cases per 1,000 for non-Hispanic whites, and 42 cases per 1,000 for non-Hispanic blacks.

      Childhood Asthma

      In 2016, over 6 million children within the U.S. (age 0-17 years) were reported as still having asthma (NCHS, 2018b) and over 3 million reported experiencing an asthma episode or attack during the previous 12 months (NCHS, 2017a; data not shown).

      As shown in Exhibit 3, crude period asthma prevalence increased on average approximately 4 percent per year between 1980 and 1996 (Akinbami et al., 2009). Rates in subsequent years (1997-2016), reported for current asthma and asthma attack prevalence, show no sharp upward or downward change through most of the time period. Since tracking began in 2001, current asthma prevalence has ranged from approximately 83 cases per 1,000 (2002 and 2013) to 96 cases per 1,000 (2009). Between 1997 and 2016, asthma attack prevalence has varied slightly, with the lowest rate of 42 per 1,000 occurring in 2015 and the highest rate of 58 cases per 1,000 occurring in 2002.

      Exhibit 4 compares crude asthma prevalence across racial and ethnic groups of children during the 2014-2016 time period. Reported current asthma prevalence was highest among black children (138 cases per 1,000), followed by American Indians/Alaska Natives (123 cases per 1,000), whites (74 cases per 1,000), and Asians (49 cases per 1,000). Asthma attack prevalence rates across racial groups followed a similar pattern to the reporting of current asthma prevalence. Exhibit 4 also compares both asthma prevalence categories for total Hispanics, non-Hispanic whites, and non-Hispanic blacks. The highest number of cases of current asthma (142 cases per 1,000) were observed among non-Hispanic blacks, followed by total Hispanics (77 cases per 1,000), and then non-Hispanic whites (73 cases per 1,000). Non-Hispanic blacks also had the highest number of asthma attack cases (73 cases per 1,000), followed by total Hispanics (40 cases per 1,000), and then non-Hispanic whites (38 cases per 1,000). 

  • Limitations
      • The NHIS questionnaire underwent major changes in 1997, and with the exception of Exhibit 3 that shows historical data for children, the data presented focus on surveys conducted from 1997 (children) and 2002 (adults) to the most currently available release (2016). The redesigned NHIS is different in content, format, and mode of data collection from earlier versions of the survey. Due to changes in methodology, 1997-2016 NHIS estimates are not directly comparable to pre-1997 NHIS estimates.

      • Prevalence data reported in the NHIS are based on self-reported responses to specific questions pertaining to airway-related illnesses, and are subject to the biases associated with self-reported data. Self-reported data may underestimate the disease prevalence being measured if, for whatever reason, the respondent is not fully aware of his/her condition.
  • Data Sources
    • Current asthma prevalence data in Exhibits 1 and 3 were obtained from annual reports and standalone tables published by NCHS (NCHS, 2004a,b, 2005a,b, 2006a-d, 2007a,b, 2008a,b, 2009a,b, 2010a,b, 2011, 2012a-c, 2014a,b, 2015a-d, 2017b,c, 2018a,b), which summarize health statistics compiled from the NHIS (https://www.cdc.gov/nchs/nhis/nhis_series.htm and https://www.cdc.gov/nchs/nhis/shs.htm). Asthma attack prevalence data from 2002 to 2016 for Exhibits 1 and 3 were obtained by running Stata analyses on the NHIS public-use data files (NCHS, 2017a), and obtained from annual reports for 1997 to 2001 data in Exhibit 3 (2002a,b, 2003a-c). The pre-1997 data for Exhibit 3 also originate from the NHIS, as compiled by NCHS in Akinbami et al. (2009). Current asthma and asthma attack prevalence data for 2014-2016 in Exhibits 2 and 4 were obtained by running Stata analyses on the NHIS public-use data files (NCHS, 2017a).

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