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Self-Reported Increase in Asthma Severity After the September 11 Attacks on the World Trade Center --- Manhattan, New York, 2001

Asthma is a chronic condition that affects approximately 14 million persons in the United States and is characterized by airway inflammation, reversible airway obstruction, and airway hyperresponsiveness to a variety of triggers (1). Both environmental and psychological factors can trigger asthma exacerbations (2--4), and a seasonal increase in asthma morbidity occurs in the fall (5). This report summarizes the results of a telephone survey conducted among Manhattan residents 5--9 weeks following the September 11, 2001, terrorist attacks on the World Trade Center (WTC) in lower Manhattan in New York City. The findings indicate that among the 13% of adult respondents with asthma, 27% reported experiencing more severe asthma symptoms after September 11. Although a normal seasonal increase in asthma severity was expected, increased severity was reported more commonly among asthmatics reporting psychological distress associated with the attacks and/or difficulty breathing because of smoke and debris during the attacks. Persons with asthma and their clinicians should be aware of the role environmental and psychological factors might play in worsening asthma after disasters.

The study data were collected as part of a survey focused primarily on the psychological impact of the attacks (6). Telephone interviews were conducted during October 16--November 15, through a random-digit--dialed sample of persons aged >18 years living south of 110th Street in Manhattan. Households were screened for geographic eligibility, and an adult with the most recent birthday was selected to be interviewed. Sample weights based on the number of telephones and adults in each household were applied to adjust for varying probabilities of being interviewed. The response rate was 64.3%. A total of 1,008 persons were interviewed, of whom 20 were excluded from the analysis because of missing weight variables. Psychological factors, including life-stressors*, depression, and risk for post-traumatic stress disorder (PTSD), were assessed by using questions documented previously (7).

Among participants, 134 (13.4%) reported having been told previously by a doctor that they had asthma; 75 (58.2%) of those with diagnosed asthma were women. The median age of the 134 participants with asthma was 36 years (range: 18--78 years); 86 (70.7%) were non-Hispanic whites, 66 (64.8%) had an annual household income of >$40,000, and 99 (72.2%) had a college or graduate degree. Of the 134 persons with asthma, 17 (12.1%) reported that they lived or were present south of Canal Street (i.e., 15 blocks north of the WTC site) at the time of the attacks.

Of the 134 respondents with diagnosed asthma, 34 (27.0%) reported worsening of asthma symptoms after the September 11 terrorist attacks, defined as having moderate to severe symptoms during the weeks since September 11 compared with having none to mild symptoms during the 4 weeks before September 11. Persons with asthma reporting worsening symptoms were more likely than those not reporting worsening symptoms to report unscheduled visits to a health-care provider (28% versus 5%; p=0.02) for asthma after September 11.

Bivariate analyses showed that an increased severity of asthma symptoms since September 11 was significantly more likely to be reported by respondents who 1) had difficulty breathing because of smoke and debris during the attacks, 2) had two or more life stressors during the 12 months before the attacks, 3) experienced a peri-event panic attack (i.e., an event that occurred at the time of or shortly after the attacks), 4) had depression during the preceding month, or 5) had symptoms of PTSD related to the attacks during the preceding month (Table). Persons with asthma who lived or were present south of Canal Street on September 11 were more likely than others to report increased asthma symptoms; however, the association was not statistically significant.

Separate multivariate logistic regression models were used that included life stressors during the preceding 12 months, peri-event panic attack, PTSD, and depression and that controlled for age, sex, race/ethnicity, income, and difficulty breathing because of smoke and debris. Having two or more life stressors during the 12 months before the attacks (odds ratio [OR]=4.4; 95% confidence interval [CI]=1.4--14.2) remained significantly associated with an increase in asthma severity after September 11; difficulty breathing because of smoke and debris also was a significant predictor of worsening asthma after September 11 (OR=7.0; 95% CI=2.3--21.3). Although peri-event panic attack (OR=2.4; 95% CI=0.8--7.4), PTSD (OR=3.6; 95% CI=0.6--20.9), and depression (OR=2.9; 95% CI=0.9--9.8) also were associated with increased severity in asthma symptoms, the relation was not statistically significant.

Reported by: J Fagan, PhD, S Galea, MD, J Ahern, MPH, S Bonner, PhD, D Vlahov, PhD, Center for Urban Epidemiologic Studies, New York Academy of Medicine, New York City. Div of Environmental Hazards and Health Effects, National Center for Environmental Health, CDC.

Editorial Note:

Particulate matter and other constituents of smoke can trigger asthma (8). Persons with asthma who reported difficulty breathing because of smoke and debris during the September 11 attacks might have been particularly sensitive to smoke from the fires that burned at the WTC site for several weeks. Psychological stress also can worsen asthma (2), and PTSD has been associated with an increase in respiratory symptoms (9) and with asthma. Even accounting for the impact of smoke and debris on asthma symptoms, adults with asthma who had two or more life stressors before September 11 (a risk factor for PTSD) were more likely to experience worsening of asthma after the attacks.

The findings in this report are subject to at least four limitations. First, no objective measures are available to validate the self-reported worsening of asthma symptoms in this population. Second, because of its cross-sectional design, this study could not establish a temporal or causal relation between worsening of asthma symptoms and psychological symptoms. Third, some selection bias cannot be ruled out; those with health problems might have been more or less likely to participate in the survey than others. Finally, because asthma severity usually increases in the fall (5), these data cannot be used to quantify the absolute impact on persons with asthma of environmental and psychological factors related to the September 11 terrorist attacks.

Despite these limitations, the survey data suggest that both the environmental and psychological sequelae of the September 11 attacks contributed to increasing symptoms experienced by some persons with asthma during the weeks following the attacks. Persons with asthma and their clinicians should be aware of the role these factors might play in worsening asthma after disasters.


  1. National Institutes of Health. Guidelines for the diagnosis and management of asthma. Bethesda, Maryland: U.S. Department of Health and Human Services, National Institutes of Health, 1997; DHHS publication no.(NIH)97-4051.
  2. Wright RJ, Rodriguez M, Cohen S. Review of psychosocial stress and asthma: an integrated biopsychosocial approach. Thorax 1998;53:1066--74.
  3. Mancuso CA, Rincon R, McCulloch CE, Charlson ME. Self-efficacy, depressive symptoms, and patients' expectations predict outcomes in asthma. Med Care 2001;39:1326--38.
  4. Eggleston PA, Buckley TJ, Breysse PN, Wills-Karp M, Kleeberger SR, Jaakkola JJ. The environment and asthma in U.S. inner cities. Environ Health Perspect 1999;107:439--50.
  5. Goldstein IF, Currie B. Seasonal patterns of asthma: a clue to etiology. Environ Res 1984;33:201--15.
  6. Galea S, Ahern J, Resnick H, et al. Psychological sequelae of the September 11 terrorist attacks in New York City. N Engl J Med 2002;346:982--7.
  7. Resnick HS, Kilpatrick DG, Dansky BS, Saunders BE, Best C. Prevalence of civilian trauma and posttraumatic stress disorder in a representative national survey of women. J Consult Clin Psychol 1993;61:984--91.
  8. Pope CA. Epidemiology of fine particulate air pollution and human health: biologic mechanisms and who's at risk. Environ Health Perspect 2000;108:713--23.
  9. McFarlane AC, Atchison M, Rafalowicz E, Papay P. Physical symptoms in post-traumatic stress disorder. J Psychosom Res 1994;38:715--26.

* Include death of a close family member; serious illness or injury; change in marital status, family, or work situation; or emotional problems.


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