Asthma is a chronic inflammatory disease that affects children and adults. The US Centres for Disease Control (CDC) has had this disease under surveillance since 1980, and uses annual surveys to monitor mortality and morbidity – the latter expressed as school and work days lost, limitation of activity, asthma exacerbations, asthma-associated emergency room visits and hospitalizations due to asthma. See Table 1 for changes or lack of changes since 1980 to 2010.
Asthma prevalence in the July 2013 CDC report, based on 2010 statistics was as follows:
- 8.5% in children (unchanged from 2004)
- 8.7% (up from 6.7% in 2004) in adults.
- 10.7% in females (up from 8.1% in 2004)
- 6.5% in males (up from 6.2% in 2004).
Individuals who are obese also have a higher prevalence of asthma at 12% than those who are overweight 7.5% compared with the 7.2% who are neither overweight or obese. Current daily smokers also had a higher prevalence of asthma 10.9% than those who never smoked 8.0%.
Poverty and Asthma
The 2013 CDC report, like the 2004 report, found that financial status also had an effect on asthma which was prevalent in:
- 13.3 % of households with incomes < $15,000
- 10.3% of household with incomes between $15,000 and $25,000
- 8.3 % of households with incomes between $25,000 to $50,000
- 8.0 % of household with incomes between $50,000 and $75,000
- 7.0 % of households with incomes of $75,000 or more.
Poverty also affected control of asthma. Gold and Yeung found that individuals with lower income levels, higher rates of unemployment and difficulty paying for healthcare reported having poorly controlled asthma.
Smith and colleagues found that among the very poor, non-Hispanic black children were at a significantly higher risk of asthma than non-Hispanic white children. They found racial/ethnic differences only among the very poor.
Race and asthma
The 2013 CDC report also found significant racial disparities associated with asthma. The 2004 figures are provided in brackets. True prevalence tends to be underestimated since studies have shown that many individuals have undiagnosed asthma.
The prevalence of asthma in blacks is 36.9% higher than in whites. In 2010 they had a 47% higher prevalence of asthma exacerbations, and a rate of hospital discharges that was 3.2 higher than whites and 2.5 times higher than other races. More blacks too were 2 to 3 times more likely to die from asthma. Black and Hispanic adults, more than white adults saw cost as a barrier to seeing primary care physicians, asthma specialists, and purchasing prescription asthma medication. Compared with whites, Gold and Yeung found that non-whites had higher usage rates of urgent care facilities, emergency rooms and hospitalizations.
Gold and Wright found that even after controlling for parental history, environmental exposure and demographic factors, black children had 1.6 times the odds of being diagnosed with asthma compared to white children. Black children who are insured by Medicaid are less likely to have a single primary-care physician and more likely to visit the emergency department for asthma care.
Impact of Asthma
It has long been known that asthma affects the individual’s quality of life. Ford and colleagues designed a cross-sectional study of 163,773 adults in 50 US states to analyse how self-reported asthma is associated with general self-reported health and four specific quality of life measures. Results were adjusted for confounders such as age, sex, educational level, employment, smoking status, level of physical activity and body mass index. Race too – whether non-Hispanic white, non-Hispanic African-American, Hispanic or “other” – was taken into account.
In reporting on the previous 30 days, when compared with individuals who never had asthma, patients with asthma had an odds ratio of:
- 2.41 for reporting poor or fair self-rated health
- 2.26 for reporting 14 days of impaired physical health
- 1.55 for reporting 14 days of impaired mental health
- 1.96 for reporting 14 days of limited activity
- 1.99 for reporting 14 days of impaired physical or mental health
The results were found consistent for all age groups, both sexes, race and ethnic groups.
The Second National Health Interview Survey found factors for the increased prevalence of asthma among black children in comparison with white children. The risk factors included:
- younger maternal age
- low birth weight
- family income
- residence in the city centre, and
- measures of overweight or obesity
Asthma Self-Management Education is a new category in the 2013 CDC report. It showed that children were more likely than adults to:
- receive self-management education
- be taught the signs and symptoms of asthma
- be taught how to respond during an asthma exacerbation
- be given an asthma action plan
- be taught how to use the asthma medication inhalers
While adults were more likely to be taught how to use a peak flow meter, less than half of adults (40.7%) and children (35.6%) were told to reduce their environmental triggers at school or at home.
- Moorman JE, Rudd RA, Johnson CA, King M, Minor P, Bailey C, Scalia MR, Akinbami LJ; Centers for Disease Control and Prevention (CDC). National surveillance for asthma--United States, 1980-2004. MMWR Surveill Summ. 2007 Oct 19;56(8):1-54.
- Centers for Disease Control and Prevention. Asthma Facts – CDC's National Asthma Control Program Grantees. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, 2013 http://www.cdc.gov/asthma/pdfs/asthma_facts_program_grantees.pdf Accessed March 2014.
- American Lung Association Trends in Asthma Morbidity and Mortality. 2012. http://www.lung.org/finding-cures/our-research/trend-reports/asthma-trend-report.pdf Accessed March 30, 2014,
- Gold LS, Yeung K, et al. Asthma control, cost and race: results from a national survey. J Asthma. 2013 Sep;50(7):783-90. doi: 10.3109/02770903.2013.795589.
- Smith LA, Hatcher-Ross JL, et al. Rethinking race/ethnicity, income, and childhood asthma: racial/ ethnic disparities concentrated among the very poor. Public Health Rep. 2005. Mar-Apr;120(2):109-16
- Gold DR, Wright R. Population disparities in asthma. Annu Rev Public Health 2005; 26:89-113
- Ford ES, Mannino DM, Homa DM, Gwynn C, Redd SC, Moriarty DG, Mokdad AH. Self-reported asthma and health-related quality of life: findings from the behavioral risk factor surveillance system. Chest. 2003;123 (1): 119-27.