What We Know From the Research
A month after 9/11, nearly 50% of people living near the WTC site who participated in a survey about their health needs and concerns said they had nose, throat or eye irritation.1
Respiratory hospital admissions increased significantly among lower Manhattan residents the first week after 9/11 compared with a similar demographic in Queens. Cardiovascular and cerebrovascular disease admissions also increased two to three weeks after 9/11, especially among women and those over 65 years of age.12
Two literature reviews focusing on birth outcomes among WTC-exposed pregnant women suggest that environmental exposure or attack-related stress reduced fetal growth in some women, a finding similar to that in studies of birth outcomes after other terrorist attacks, environmental/chemical disasters and natural disasters. Disaster literature not specific to 9/11 indicates that child development may be more influenced by maternal mental health than by direct effects of disaster-related pre-natal stress.2,21 A newer study not included in these reviews compared two groups of women who were pregnant between September 11 and December 1, 2001: 500 women who were enrolled in the WTC Health Registry, and 50,000 women who lived at least 5 miles from the WTC site. Although researchers found similar birth weight and gestational age at delivery in the groups, Registry enrollees with probable PTSD were more likely than women without PTSD to deliver premature or underweight babies.22
A study compared the estimated smoke plume path 5 days after 9/11 with health survey findings of about 3,000 New Yorkers 6 months after 9/11. Of respondents outside lower Manhattan, the study showed no connection between the estimated smoke plume intensity and new or worsening respiratory symptoms among those with asthma. However, the smoke plume was different from the WTC dust cloud.3
Among a small group of lower Manhattan residents, lower respiratory symptoms, such as a cough and wheezing, decreased almost 8% four years after 9/11. Yet the prevalence remained elevated compared with those not exposed to 9/11. Residents who also worked in lower Manhattan on 9/11 were at highest risk for persistent symptoms.13
Eight percent (8%) of residents enrolled in the WTC Health Registry reported newly diagnosed asthma 5 to 6 years after 9/11. Intense dust cloud exposure on 9/11, experiencing a heavy coating of dust in the home and not evacuating homes were major contributors to new asthma diagnoses.4
A study of nearly 2,000 people exposed to WTC dust who sought care at the WTC Environmental Health Center 5 to 7 years after 9/11 showed high rates of respiratory symptoms, including persistent shortness of breath, cough and sinus or nasal problems. While pulmonary function was normal for the total group, about one-third (31%) had below-normal pulmonary function similar to the level found in WTC rescue, recovery and clean up workers.5
The WTC Health Registry, in collaboration with the WTC Environmental Health Center, found abnormal lung function in Lower Manhattan residents and area workers who reported persistent respiratory symptoms 7 to 8 years after exposure to the WTC disaster. In a case control study using spirometry and oscillometry, a test to measure how well the lungs’ small airways are working, researchers found that 180 enrollees with persistent respiratory symptoms (cases) were more likely to have abnormal lung function than nearly 500 enrollees who had not reported any new respiratory symptoms since 9/11 (controls). Oscillometric abnormalities were found even among cases with normal spirometry.23
WTC Health Registry researchers identified 790 deaths from 2003 through 2009 among 41,930 adults who resided in New York City at the time of their enrollment in the Registry. The all-cause death rate among Registry enrollees was 43% lower than among NYC residents as a whole. Researchers detected exposure-related differences in mortality rates among those in the Registry: lower Manhattan residents, area workers and passersby with intermediate or high levels of exposure, including those with 2 or more injuries on 9/11, had elevated all-cause and heart disease mortality risks in comparison to those with intermediate or lower levels of exposure. The study did not detect exposure-related mortality differences among rescue and recovery workers even when internal comparisons were conducted.24
Researchers found an association between chronic WTC exposures and lower respiratory symptoms in a case control study of nearly 800 Lower Manhattan residents and area workers in the WTC Health Registry up to 6 years after 9/11. Residents reporting lower respiratory symptoms were 2 to 3 times more likely than residents who never had symptoms to recall that the surfaces in their homes were covered in dust following the WTC collapse; residents who recalled a thicker layer of dust were at greater risk, suggesting a dose/response relationship.27
Among residents, office workers and passers-by enrolled in the WTC Health Registry who reported either lower respiratory symptoms or probable posttraumatic stress disorder, more than 25% said they had both conditions 5-6 years after 9/11. Also, enrollees who had both conditions were much more likely to report 14 days of activity lost in the 30 days before being surveyed compared to enrollees with only 1 condition.28
In a longitudinal study of nearly 1,000 office workers, residents and clean-up workers who sought care for respiratory illness at the World Trade Center Environmental Health Center between 2005 and 2011, and who were symptom-free prior to 9/11, researchers found improvements in lung function overall among treated patients who were not heavy smokers. However, lung function among office workers, who had the highest likelihood of dust cloud exposure, improved the least.29
A WTC Health Registry analysis of verified cancer diagnoses among 33,928 adult enrollees NOT involved in rescue and recovery work, including Lower Manhattan residents, found no increase in cancer rates compared to non-exposed New York State residents during the period studied (2003-2008).30
Those directly affected by 9/11 were more likely to report post-traumatic stress disorder (PTSD) symptoms 6 months after 9/11. However, a substantial number not directly affected also met the criteria for probable PTSD.6
In a study that examined the prevalence of resilience among New Yorkers during the 6 months after 9/11, 65% of participants showed resilience (ability to recover). This suggests that more New Yorkers demonstrated resilience during the 6 months after 9/11 than previously believed. Even among those with the highest levels of exposure and highest probable PTSD, the proportion that were resilient never dropped below 33%.7
A study of low-income patients seven to 16 months after 9/11 found that:
- Those suffering a 9/11-related loss were twice as likely to be diagnosed with a mental health condition, such as depression, anxiety or PTSD.14
- This group was also more likely to suffer functional impairment and work loss.14
- Patients with loved ones in danger on 9/11 or who knew someone involved in the rescue and recovery effort were twice as likely to suffer from an anxiety disorder.15
A small study of New Yorkers 18 to 21 years of age with and without generalized anxiety disorder compared their mental health before and after 9/11. Among those with generalized anxiety disorder, findings showed high rates of functional impairment but no increase in post-traumatic stress symptoms.8
A study of 2,300 New Yorkers interviewed 1, 2 and 3 years after 9/11 showed that:
- People who received early, brief interventions at their worksites reported better mental health than those who received more extensive interventions, such as psychotherapy of 30 minutes or longer. Although the study adjusted for 9/11 exposure, it did not adjust for illness severity. Support from friends, neighbors and spiritual communities was also beneficial.9
- Problem drinking and alcohol use were connected with psychological trauma up to 4 years after 9/11, as well as other mental health problems.10
Analyses of NYC death records that compared suicide rates before and after 9/11 found that suicide rates did not increase four years after the terrorist attacks.16,17
Among a sample of 455, mostly female patients who were screened for mental health conditions when they sought primary care at a general medicine clinic in New York City, the PTSD rate decreased significantly from 9.6% 1 year after 9/11 to 4.1% 3 years later. Patients who reported pre-9/11 depression, the only significant predictor of PTSD trajectory, were 10 times more likely to have PTSD 4 years after the WTC attacks than those who didn’t.25
A study of national mortality data showed that suicide rates among New Yorkers declined significantly six months after 9/11.18
Lower-income New Yorkers exposed to ongoing stress and trauma were more likely to suffer from persistent depression.19
While low-income adolescents and mothers exposed to the WTC disaster were more likely to suffer from depression and PTSD 15 months after 9/11, respectively, there were few long-term associations between 9/11 exposure and mental health among this group.20
More than 21% of residents enrolled in the WTC Health Registry reported new PTSD symptoms 5 to 6 years after 9/11. Probable PTSD among residents increased from more than 13% 2-3 years after the attacks to more than 16% 5-6 years later. Risk factors included:
- Intense dust cloud exposure
- Witnessing horror
- Returning to a home with a heavy layer of dust
- Job loss
- Lack of social support11
To search for 2003/2004 baseline survey data, visit the Health Department's interactive data tool.
A small, cross-sectional study assessed more than 300 low-income, trauma-exposed patients in a large urban primary care clinic, including some who had been exposed to the WTC disaster, for mental health disorders and functioning at 2 time points after 9/11. Although patients with a past PTSD diagnosis functioned better than patients with a current PTSD diagnosis, they continued to experience more difficulties with their social and family lives than patients who had never been diagnosed with PTSD.26
- Kramer R, Hayes MA, Nolan V, et al. Community needs assessment of lower Manhattan residents following the World Trade Center Attacks — Manhattan, New York City, 2001. Morbidity and Mortality Weekly Report. 2002. 51;10-13.
- Ohlsson A, Shah PS; the Knowledge Synthesis Group of Determinants of Preterm/LBW births. Effects of the September 11, 2001 Disaster on Pregnancy Outcomes: A Systematic Review. Acta Obstetricia et Gynecologica Scandinavica. 2011;90(1):6-18.
- Laumbach RJ, Harris G, Kipen HM, et al. Lack of Association Between Estimated WTC Plume Intensity and Respiratory Symptoms among New York City Residents Outside of Lower Manhattan. American Journal of Epidemiology 2009; [Epub ahead of print].
- Brackbill RM, Hadler JL, Ekenga CC, et al. Asthma and Posttraumatic Stress Symptoms 5 to 6 Years Following Exposure to the WTC Terrorist Attack. Journal of the American Medical Association 2009; 302(5):502-516.
- Reibman J, Liu M, Cheng Q, et al. Characteristics of a Residential and Working Community with Diverse Exposure to WTC Dust, Gas and Fumes. Journal of Occupational and Environmental Medicine 2009; 51(5):534-541.
- Galea S, Vlahov D, Resnick H, et al. Trends of probable post-traumatic stress disorder in New York City after the September 11 terrorist attacks. American Journal of Epidemiology. 2003. 58;514-524.
- Bonanno GA, Galea S, Bucciarelli A, et al. Psychological resilience after disaster: New York City in the aftermath of the September 11th terrorist attacks. Psychological Science 2006. 17;181-186.
- Farach FJ, Mennin DS, Smith RL, & Mandelbaum M. The Impact of Pretrauma Analogue GAD and Posttraumatic Emotional Reactivity Following Exposure to the September 11 Terrorist Attacks: A Longitudinal Study. Behavior Therapy 2008; 39: 262-276.
- Boscarino JA & Adams RE. Overview of Findings from the WTC Disaster Outcome Study: Recommendations for Future Research after Exposure to Psychological Trauma. International Journal of Emergency Mental Health 2008; 10(4): 275-290.
- Cerda M, Vlahov D, Tracy M & Galea S. Alcohol Use Trajectories among Adults in an Urban Area after a Disaster: Evidence from a Population-based Cohort Study. Addiction 2008; 103: 1296-1307.11.
- Brackbill RM, Hadler JL, Ekenga CC, et al. Asthma and Posttraumatic Stress Symptoms 5 to 6 Years Following Exposure to the WTC Terrorist Attack. Journal of the American Medical Association 2009; 302(5): 502-516.
- Lin S, Gomez MI, Gensburg L, et al. Respiratory and Cardiovascular Hospitalizations after the World Trade Center Disaster. Archives of Environmental & Occupational Health 2010; 65(1):12-20.
- Lin S, Jones R, Reibman J, Morse D, Hwang SA. Lower Respiratory Symptoms Among Residents Living Near the World Trade Center, Two and Four Years After 9/11. International Journal of Occupational and Environmental Health. 2010 16(1):44-52.
- Neria Y, Olfson M, Gameroff MJ et al. The Mental Health Consequences of Disaster-related Loss: Findings from Primary Care One Year after the 9/11 Terrorist Attacks. Psychiatry. 2008 71(4):339-348.
- Ghafoori B, Neria Y, Gameroff MJ et al. Screening for Generalized Anxiety Disorder Symptoms in the Wake of Terrorist Attacks: A Study in Primary Care. Journal of Traumatic Stress. 2009 22(3): 218-226.
- Mezuk B, Larkin GL, Prescott MR, et al. The Influence of a Major Disaster on Suicide Risk in the Population. Journal of Traumatic Stress. 2009 22(6):481-488.
- Pridemore WA, Trahan A & Chamlin MB. No Evidence of Suicide Increase Following Terrorist Attacks in the United States: An Interrupted Time-series Analysis of September 11 and Oklahoma City. Suicide & Life Threatening Behavior. 2009 39(6):659-670.
- Claassen CA, Carmody T, Stewart SM et al. Effect of 11 September 2001 Terrorist Attacks in the USA on Suicide in Areas Surrounding the Crash Sites. British Journal of Psychiatry. 2010 196(5):359-364.
- Nandi A, Tracy M, Beard JR et al. Patterns and Predictors of Trajectories of Depression after an Urban Disaster. Annals of Epidemiology. 2009 19(11):761-770.
- Gershoff ET, Aber JL, Ware A et al. Exposure to 9/11 Among Youth and Their Mothers in New York City: Enduring Associations With Mental Health and Sociopolitical Attitudes. Child Development. 2010 81;4:1142-1160.
- Harville E, Xiong X, Buekens P. Disasters and Perinatal Health: A Systematic Review. Obstetrical & Gynecological Survey. 2010;65(11):713-28.
- Lipkind HS, Curry, AE, Huynh M et al. Birth Outcomes Among Offspring of Women Exposed to the September 11, 2001, Terrorist Attacks. Obstetrics & Gynecology. 2010;116(4):917-925.
- Friedman SM, Maslow CB, Reibman J et al. Case-control Study of Lung Function in World Trade Center Health Registry Area Residents and Workers. American Journal of Respiratory Critical Care Medicine. 2011 June 3.
- Jordan HT, Brackbill RM, Cone JE et al. Mortality Among Survivors of the Sept 11, 2001, World Trade Center Disaster: Results from the World Trade Center Health Registry Cohort. Lancet. 2011;378:898-905.
- Neria Y, Ofson M, Gameroff MJ et al. Long-term Course of Probable PTSD After the 9/11 Attacks: A Study in Urban Primary Care. Journal of Traumatic Stress. 2010;23(4): 474-482.
- Westphal M, Olfson M, Gameroff MJ et al. Functional Impairment in Adults with Past Posttraumatic Stress Disorder: Findings from Primary Care. Depression and Anxiety. 2011;28(8):686-695.
- Maslow CB, Friedman SM, Pillai PS et al. Chronic and Acute Exposures to the World Trade Center Disaster and Lower Respiratory Symptoms: Area Residents and Workers. American Journal of Public Health. 2012 Apr 19. [Epub ahead of print]
- Nair HP, Ekenga CC, Cone JE et al. Co-occurring Lower Respiratory Symptoms and Posttraumatic Stress Disorder 5 to 6 Years After the World Trade Center Terrorist Attack. American Journal of Public Health. 2012 Aug 16. [Epub ahead of print]
- Liu M, Qian M, Cheng Q et al. Longitudinal Spirometry Among Patients in a Treatment Program for Community Members With World Trade Center-Related Illness. Journal of Occupational & Environmental Medicine. 2012 Sep 19. [Epub ahead of print]
- Li J, Cone JE, Kahn AR et al. Association between World Trade Center Exposure and Excess Cancer Risk. Journal of the American Medical Association. 2012 Dec 19;308(23):2479-88.