Novel approach to studying effects of inhalational exposure on lung function in civilians exposed to the World Trade Center disaster

It is increasingly important to study the impact of environmental inhalation exposures on human health in natural or man-made disasters in civilian populations. The members of the World Trade Center Environmental Health Center (WTC EHC; WTC Survivors) had complex exposures to environmental disaster from the destruction of WTC towers and can serve to reveal the effects of WTC exposure on the entire spectrum of lung functions. We aimed to investigate the associations between complex WTC exposures and measures of spirometry and oscillometry in WTC Survivors and included 3605 patients enrolled between Oct 1, 2009 and Mar 31, 2018. We performed latent class analysis and identified five latent exposure groups. We applied linear and quantile regressions to estimate the exposure effects on the means and various quantiles of pre-bronchodilator (BD) % predicted forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio, as well as the resistance at an oscillating frequency of 5 Hz (R5), frequency dependence of resistance R5-20, and reactance area (AX). Compared with Group 5, which had low or unknown exposure and was treated as the reference group, Group 1, the local workers with both acute and chronic exposures, had a lower median of % predicted FVC (-3.6; 95% CI: -5.4, -1.7) and higher (more abnormal) measures of AX at 10th quantile (0.77 cmH2O L-1 s; 95% CI: 0.41, 1.13) and 25th quantile (0.80 cmH2O L-1 s; 95% CI: 0.41, 1.20). Results suggested heterogeneous exposures to the WTC disaster had differential effects on the distributions of lung functions in the WTC Survivors. These findings could provide insights for future investigation of environmental disaster exposures.

Spirometric Abnormalities and Lung Function Decline in Current and Former Microwave Popcorn and Current Flavoring Manufacturing Workers

OBJECTIVE

The aim of this study was to compare spirometry results in microwave popcorn and flavoring manufacturing workers.

METHODS

We used NIOSH data on current and former microwave popcorn workers (MPWs) and surveillance data on flavoring manufacturing workers (FMWs).

RESULTS

Former MPW had higher prevalence of mixed and high severity abnormalities, some had excessive lung function drops. Current MPW had lowest occurrence of excessive lung function drops. FMW with excessive drops and spirometric abnormalities at last test had developed a restrictive pattern. Spirometric abnormalities and excessive drops were associated with work-related factors.

CONCLUSION

There was evidence of a healthy worker survivor effect in MPW. Importantly, removal from exposure did not always stabilize lung function decline indicating a need for continued monitoring. The development of a restrictive pattern should raise the level of suspicion for possible work-related disease in flavoring-exposed workers.

Association of quantitative CT lung density measurements and lung function decline in World Trade Center workers

BACKGROUND

Occupational exposures at the WTC site after 11 September 2001 have been associated with presumably inflammatory chronic lower airway diseases.

AIMS

In this study, we describe the trajectories of expiratory air flow decline, identify subgroups with adverse progression, and investigate the association of those trajectories with quantitative computed tomography (QCT) imaging measurement of increased and decreased lung density.

METHODS

We examined the trajectories of expiratory air flow decline in a group of 1,321 former WTC workers and volunteers with at least three periodic spirometries, and using QCT-measured low (LAV%, -950 HU) and high (HAV%, from -600 to -250 HU) attenuation volume percent. We calculated the individual regression line slopes for first-second forced expiratory volume (FEV₁ slope), identified subjects with rapidly declining ("accelerated decliners") and increasing ("improved"), and compared them to subjects with "intermediate" (0 to -66.5 mL/year) FEV₁ slope. We then used multinomial logistic regression to model those three trajectories, and the two lung attenuation metrics.

RESULTS

The mean longitudinal FEV₁ slopes for the entire study population, and its intermediate, decliner, and improved subgroups were, respectively, -40.4, -34.3, -106.5, and 37.6 mL/year. In unadjusted and adjusted analyses, LAV% and HAV% were both associated with "accelerated decliner" status (OR_adj , 95% CI 2.37, 1.41-3.97, and 1.77, 1.08-2.89, respectively), compared to the intermediate decline.

CONCLUSIONS

Longitudinal FEV₁ decline in this cohort, known to be associated with QCT proximal airway inflammation metric, is also associated with QCT indicators of increased and decreased lung density. The improved FEV₁ trajectory did not seem to be associated with lung density metrics.

Association of low FVC spirometric pattern with WTC occupational exposures

BACKGROUND

A reduced forced vital capacity without obstruction (low FVC) is the predominant spirometric abnormality reported in workers and volunteers exposed to dust, gases, and fumes at the World Trade Center (WTC) disaster site in 2001-2002. While low FVC has been associated with obesity and metabolic syndrome, its association with WTC occupational exposures has not been demonstrated. We estimated the prevalence of this abnormality and examined its association with WTC exposure level.

METHODS

Longitudinal study of the relation between arrival at the WTC site within 48 h and FVC below the lower limit of normal (FVC < LLN, with normal FEV1/FVC ratio) at any time in 10,284 workers with at least two spirometries between 2002 and 2018. Logistic regression and linear mixed models were used for the multivariable analyses.

RESULTS

The prevalence of low FVC increased from 17.0% (95% CI 15.4%, 18.5%) in June 2003, to 26.4% (95% CI 24.8%, 28.1%) in June 2018, and exceeded at both times that of obstruction. The rate of FVC decline was -43.7 ml/year during the study period. In a multivariable analysis adjusting for obesity, metabolic syndrome indicators, and other factors, early arrival at the WTC disaster site was significantly associated with low FVC, but only among men (ORadj = 1.29, 95% CI 1.17, 1.43). Longitudinal FVC rate of decline did not differ by WTC site arrival time.

CONCLUSIONS

Among WTC workers, the prevalence of low FVC increased over a 16-year period. Early arrival to the WTC disaster site was significantly associated with low FVC in males.

Quantitative CT Evidence of Airway Inflammation in WTC Workers and Volunteers with Low FVC Spirometric Pattern

BACKGROUND

The most common abnormal spirometric pattern reported in WTC worker and volunteer cohorts has consistently been that of a nonobstructive reduced forced vital capacity (low FVC). Low FVC is associated with obesity, which is highly prevalent in these cohorts. We used quantitative CT (QCT) to investigate proximal and distal airway inflammation and emphysema in participants with stable low FVC pattern.

METHODS

We selected study participants with at least two available longitudinal surveillance spirometries, and a chest CT with QCT measurements of proximal airway inflammation (wall area percent, WAP), end-expiratory air trapping, suggestive of distal airway obstruction (expiratory to inspiratory mean lung attenuation ratio, MLA_EI), and emphysema (percentage of lung volume with attenuation below - 950 HU, LAV%). The comparison groups in multinomial logistic regression models were participants with consistently normal spirometries, and participants with stable fixed obstruction (COPD).

RESULTS

Compared to normal spirometry participants, and after adjusting for age, sex, race/ethnicity, BMI, smoking, and early arrival at the WTC disaster site, low FVC participants had higher WAP (OR_adj 1.24, 95% CI 1.06, 1.45, per 5% unit), suggestive of proximal airway inflammation, but did not differ in MLA_EI, or LAV%. COPD participants did not differ in WAP with the low FVC ones and were more likely to have higher MLA_EI or LAV% than the other two subgroups.

DISCUSSION

WTC workers with spirometric low FVC have higher QCT-measured WAP compared to those with normal spirometries, but did not differ in distal airway and emphysema measurements, independently of obesity, smoking, and other covariates.

Lung Function Decline in Farm and Nonfarm Rural Residents of Saskatchewan

OBJECTIVE

This study aims to assess the annual changes in lung function among farm and nonfarm adult residences in rural Saskatchewan, Canada.

METHODS

Data from the Saskatchewan Rural Health Study survey (2010 to 2014) among 724 adults were used.

RESULTS

For forced expiratory volume in 1 second (FEV1) measurements, estimates of annual decline (in milliliters) were highest in older age male (65+ years) (Mean, SD) (-42.63, 21.16); and among old heavy smokers (-57.79, 24.30). Estimates of annual decline in forced vital capacity (FVC) were highest in current smokers without the use of natural gas (-25.78, 14.78) and among old heavy smokers (-33.88, 20.28). Living on a farm is associated with decreased FEV1 and FVC, but not statistically significant by sex and age.

CONCLUSIONS

A complex mix of personal and contextual factors may affect these estimates.

Elevated prevalence of moderate-to-severe hepatic steatosis in World Trade Center General Responder Cohort in a program of CT lung screening

BACKGROUND AND AIMS

To determine the prevalence of moderate-to-severe hepatic steatosis (HS) and associated risk factors in members of the World Trade Center (WTC) General Responder Cohort (GRC) who qualify for low-dose non-contrast computed tomography for lung cancer screening and compare them to non-WTC participants in the same screening program.

METHODS

All participants gave written informed consent before participating in this IRB-approved study. Clinical variables and laboratory values were recorded. Hepatic attenuation measurement (Hounsfield unit; HU) was measured on low-dose computed tomography (LDCT) and a threshold attenuation value <40HU indicated moderate-to-severe HS. Bivariate and multivariable linear and logistic regression analyses were performed. Propensity scores (PS) were calculated and inverse probability weighting (IPW) was used to adjust for potential confounders when comparing the WTC with non-WTC participants.

RESULTS

The prevalence of moderate-to-severe HS was 16.2% among 154 WTC participants compared to 5.3% among 170 non-WTC participants. In WTC members, moderate-to-severe HS was associated with higher BMI, higher laboratory liver function tests, and former smoking status. Using PS analysis and IPW to account for potential confounders, the odds ratio for moderate-to-severe HS was 3.4-fold higher (95% confidence interval: 1.7-6.7) in the WTC participants compared with non-WTC participants. Moderate-to-severe HS was also associated with higher BMI and former smoker status.

CONCLUSION

Prevalence of moderate-to-severe HS was >3-fold higher in the WTC-GRC group than in other participants.

Association of Obesity with Quantitative Chest CT Measured Airway Wall Thickness in WTC Workers with Lower Airway Disease

BACKGROUND

We previously reported that wall area percent (WAP), a quantitative CT (QCT) indicator of airway wall thickness and, presumably, inflammation, is associated with adverse longitudinal expiratory flow trajectories in WTC workers, but that obesity and weight gain also seemed to be independently predictive of the latter. Previous studies have reported no association between WAP and obesity, so we investigated that association in nonsmoking WTC-exposed individuals and healthy unexposed controls.

METHODS

We assessed WAP using the Chest Imaging Platform QCT system in a segmental bronchus in 118 former WTC workers, and 89 COPDGene® WTC-unexposed and asymptomatic subjects. We used multiple regression to model WAP vs. body mass index (BMI) in the two groups, adjusting for important subject and CT image characteristics.

RESULTS

Unadjusted analyses revealed significant differences between the two groups with regards to WAP, age, gender, scan pixel spacing and slice interval, but not BMI or total lung capacity. In adjusted analysis, there was a significant interaction between BMI and WTC exposure on WAP. BMI was significantly and positively associated with WAP in the WTC group, but not in the COPDGene® group, but stratified analyses revealed that the effect was significant in WTC subjects with clinical evidence of lower airway disease (LAD).

DISCUSSION

Unlike non-diseased subjects, BMI was significantly associated with WAP in WTC workers and, in stratified analyses, the association was significant only among those with LAD. Our findings suggest that this adverse effect of obesity on airway structure and inflammation may be confined to already diseased individuals.

Shortened leukocyte telomere length is associated with reduced pulmonary function and greater subsequent decline in function in a sample of World Trade Center responders

The objective of this study was to examine whether shorter leukocyte telomere length (LTL) is associated with more rapid pulmonary function decline in a longitudinal study of World Trade Center (WTC) responders. WTC responders (N = 284) participating in a monitoring study underwent blood sampling and were followed prospectively for spirometric outcomes. A single blood sample was taken to measure LTL using southern blotting. Outcomes included percent-predicted one-second forced expiratory volume (FEV1%), forced vital capacity (FVC%), and the FEV1/FVC ratio. In a subset, percent-predicted diffusing capacity (DLCO%) was also measured. Longitudinal modeling examined prospectively collected information over five years since blood was banked was used to examine the rate of change in pulmonary functioning over time. Severity of WTC exposure was assessed. Shorter LTL was associated with lower FEV1% and FVC% at baseline. For example, 29.9% of those with LTL <6.5 kbps had FEV1% <80% whereas only 12.4% of those with LTL ≥6.5 had FEV1% <80% (RR = 2.53, 95%CI = [1.70–3.76]). Lower DLCO% was also significantly associated with shorter LTL. Longitudinal models identified a prospective association between shorter LTL and greater yearly rates of decline in FEV1% (0.46%/year, 95%CI = [0.05–0.87]) and in the FEV1/FVC ratio (0.19%/year, 95%CI = [0.03–0.36]). There were no associations between severity of exposure and either LTL or pulmonary function. Longitudinal analyses revealed that shorter LTL, but not severity of WTC exposures, was associated with poorer pulmonary functioning and with greater subsequent decline in pulmonary functioning over time. These findings are consistent with the idea that shortened LTL may act as a biomarker for enhanced pulmonary vulnerability in the face of acute severe toxic inhalation exposures.

Receptor for advanced glycation end-products and environmental exposure related obstructive airways disease: a systematic review

Background

Our group has identified the receptor for advanced glycation end-products (RAGE) as a predictor of World Trade Center particulate matter associated lung injury. The aim of this systematic review is to assess the relationship between RAGE and obstructive airways disease secondary to environmental exposure.

Methods

A comprehensive search using PubMed and Embase was performed on January 5, 2018 utilising keywords focusing on environmental exposure, obstructive airways disease and RAGE and was registered with PROSPERO (CRD42018093834). We included original human research studies in English, focusing on pulmonary end-points associated with RAGE and environmental exposure.

Results

A total of 213 studies were identified by the initial search. After removing the duplicates and applying inclusion and exclusion criteria, we screened the titles and abstracts of 61 studies. Finally, 19 full-text articles were included. The exposures discussed in these articles include particulate matter (n=2) and cigarette smoke (n=17).

Conclusion

RAGE is a mediator of inflammation associated end-organ dysfunction such as obstructive airways disease. Soluble RAGE, a decoy receptor, may have a protective effect in some pulmonary processes. Overall, RAGE is biologically relevant in environmental exposure associated lung disease. Future investigations should focus on further understanding the role and therapeutic potential of RAGE in particulate matter exposure associated lung disease.

RAGE is biologically relevant in environmental exposure associated lung disease. Future investigations should focus on further understanding the role and therapeutic potential of RAGE in particulate matter exposure associated lung diseasehttp://ow.ly/gfZz30o7otU

The development of a Biobank of cancer tissue samples from World Trade Center responders

Background

World Trade Center (WTC) responders were exposed to mixture of dust, smoke, chemicals and carcinogens. Studies of cancer incidence in this population have reported elevated risks of cancer compared to the general population. There is a need to supplement current epidemiologic cancer follow-up with a cancer tissue bank in order to better elucidate a possible connection between each cancer and past WTC exposure. This work describes the implementation of a tissue bank system for the WTC newly diagnosed cancers, focused on advancing the understanding of the biology of these tumors. This will ultimately impact the modalities of treatment, and the probability of success and survival of these patients.

Methods

WTC Responders who participated (as employees or volunteers) in the rescue, recovery and cleanup efforts at the WTC sites have been enrolled at Mount Sinai in the World Trade Center Health Program. Responders with cancer identified and validated through linkages with New York, New Jersey, Pennsylvania, and Connecticut cancer registries were eligible to participate in this biobank. Potential participants were contacted through letters, phone calls, and emails to explain the research study, consent process, and to obtain the location where their cancer procedure was performed. Pathology departments were contacted to identify and request tissue samples.

Results

All the 866 solid cancer cases confirmed by the Data Center at Mount Sinai have been contacted and consent was requested for retrieval and storage of the tissue samples from their cancer. Hospitals and doctors’ offices were then contacted to locate and identify the correct tissue block for each patient. The majority of these cases consist of archival paraffin blocks from surgical patients treated from 2002 to 2015. At the time of manuscript writing, this resulted in 280 cancer samples stored in the biobank.

Conclusions

A biobank of cancer tissue from WTC responders has been compiled with 280 specimens in storage to date. This tissue bank represents an important resource for the scientific community allowing for high impact studies on environmental exposures and cancer etiology, cancer outcome, and gene-environment interaction in the unique population of WTC responders.

Increased Airway Wall Thickness is Associated with Adverse Longitudinal First-Second Forced Expiratory Volume Trajectories of Former World Trade Center workers

RATIONALE

Occupational exposures at the WTC site after September 11, 2001 have been associated with several presumably inflammatory lower airway diseases. In this study, we describe the trajectories of expiratory air flow decline, identify subgroups with adverse progression, and investigate the association of a quantitative computed tomography (QCT) imaging measurement of airway wall thickness, and other risk factors for adverse progression.

METHODS

We examined the trajectories of expiratory air flow decline in a group of 799 former WTC workers and volunteers with QCT-measured (with two independent systems) wall area percent (WAP) and at least 3 periodic spirometries. We calculated individual regression lines for first-second forced expiratory volume (FEV₁), identified subjects with rapidly declining and increasing ("gainers"), and compared them to subjects with normal and "stable" FEV₁ decline. We used multivariate logistic regression to model decliner vs. stable trajectories.

RESULTS

The mean longitudinal FEV₁slopes for the entire study population, and its stable, decliner, and gainer subgroups were, respectively, - 35.8, - 8, - 157.6, and + 173.62 ml/year. WAP was associated with "decliner" status (OR_adj 1.08, 95% CI 1.02, 1.14, per 5% increment) compared to stable. Age, weight gain, baseline FEV₁ percent predicted, bronchodilator response, and pre-WTC occupational exposures were also significantly associated with accelerated FEV₁ decline. Analyses of gainers vs. stable subgroup showed WAP as a significant predictor in unadjusted but not consistently in adjusted analyses.

CONCLUSIONS

The apparent normal age-related rate of FEV₁ decline results from averaging widely divergent trajectories. WAP is significantly associated with accelerated air flow decline in WTC workers.

Airway Disease in Rescue/Recovery Workers: Recent Findings from the World Trade Center Collapse

PURPOSE OF REVIEW

Our goal is to summarize the airway disease literature since September 11, 2001 (9/11), focusing on studies published since 2011 in World Trade Center-exposed rescue/recovery workers.

RECENT FINDINGS

Since 2011, studies have confirmed relationships between initial World Trade Center exposure intensity, severity of symptoms, airway disease diagnoses, and biomarkers of disease progression. Studies continue to document ongoing morbidity in rescue/recovery workers over 10 years after 9/11. Future research should further identify correlates of symptom persistence and new airway disease diagnoses. The unique characteristics of the airway diseases in this population warrant ongoing monitoring and treatment.

Lung function decline in subjects with and without COPD in a population-based cohort in Latin-America

BACKGROUND

Lung-function decline is one of the possible mechanisms leading to Chronic Obstructive Pulmonary Disease (COPD).

METHODS

We analyzed data obtained from two population-based surveys of adults (n = 2026) conducted in the same individuals 5-9 years (y) after their baseline examination in three Latin-American cities. Post BronchoDilator (postBD) FEV1 decline in mL/y, as %predicted/y (%P/y) and % of baseline/y (%B/y) was calculated and the influence of age, gender, BMI, baseline lung function, BD response, exacerbations rate evaluated using multivariate models.

RESULTS

Expressed in ml/y, the mean annual postBD FEV1 decline was 27 mL (0.22%P, 1.32%B) in patients with baseline COPD and 36 (0.14%P, 1.36%B) in those without. Faster decline (in mL/y) was associated with higher baseline lung function, with significant response to bronchodilators, older age and smoking at baseline, also in women with chronic cough and phlegm, or ≥2 respiratory exacerbations in the previous year, and in men with asthma.

CONCLUSIONS

Lung function decline in a population-based cohort did not differ in obstructed and non-obstructed individuals, it was proportional to baseline FEV1, and was higher in smokers, elderly, and women with respiratory symptoms.

Risk factors for persistence of lower respiratory symptoms among community members exposed to the 2001 World Trade Center terrorist attacks

Objectives

We studied the course of lower respiratory symptoms (LRS; cough, wheeze or dyspnoea) among community members exposed to the 9/11/2001 World Trade Center (WTC) attacks during a period of 12–13 years following the attacks, and evaluated risk factors for LRS persistence, including peripheral airway dysfunction and post-traumatic stress disorder (PTSD).

Methods

Non-smoking adult participants in a case-control study of post-9/11-onset LRS (exam 1, 2008–2010) were recruited for follow-up (exam 2, 2013–2014). Peripheral airway function was assessed with impulse oscillometry measures of R₅ and R_5-20. Probable PTSD was a PTSD checklist score ≥44 on a 2006–2007 questionnaire.

Results

Of 785 exam 1 participants, 545 (69%) completed exam 2. Most (321, 59%) were asymptomatic at all assessments. Among 192 participants with initial LRS, symptoms resolved for 110 (57%) by exam 2, 55 (29%) had persistent LRS and 27 (14%) had other patterns. The proportion with normal spirometry increased from 65% at exam 1 to 85% at exam 2 in the persistent LRS group (p<0.01) and was stable among asymptomatic participants and those with resolved LRS. By exam 2, spirometry results did not differ across symptom groups; however, R₅ and R_5-20 abnormalities were more common among participants with persistent LRS (56% and 46%, respectively) than among participants with resolved LRS (30%, p<0.01; 27%, p=0.03) or asymptomatic participants (20%, p<0.001; 8.2%, p<0.001). PTSD, R₅ at exam 1, and R_5-20 at exam 1 were each independently associated with persistent LRS.

Conclusions

Peripheral airway dysfunction and PTSD may contribute to LRS persistence. Assessment of peripheral airway function detected pulmonary damage not evident on spirometry. Mental and physical healthcare for survivors of complex environmental disasters should be coordinated carefully.

Obesity and weight gain among former World Trade Center workers and volunteers

A high prevalence of obesity has been observed among former World Trade Center (WTC) workers and volunteers. We hypothesized that unemployment and disability status would predict obesity. We surveyed 220 participants at the [INST] Mount Sinai WTC Clinical Center to assess their obesity and current employment and disability status, WTC occupational exposure level, medical comorbidities, and dietary and exercise habits. Bivariate and logistic regression multivariate analyses were used to explore associated risk factors. Obesity was associated with active employment status. Other significant covariates included non-Latino African American race, having a high number of comorbid chronic diseases, low exercise frequency, and not drinking any glass of juice daily. The association of obesity with active employment suggests that interventions that favor healthy habits among actively employed individuals are warranted.

A follow-up study of airway symptoms and lung function among residents and workers 5.5 years after an oil tank explosion

Background

Assess if people who lived or worked in an area polluted after an oil tank explosion had persistent respiratory health impairment as compared to a non-exposed population 5.5 years after the event.

Methods

A follow-up study 5.5 years after the explosion, 330 persons aged 18–67 years, compared lung function, lung function decline and airway symptoms among exposed persons (residents <6 km from the accident site or working in the industrial harbour at the time of the explosion) with a non-exposed group (residence >20 km away). Also men in the exposed group who had participated in accident related tasks (firefighting or clean-up of pollution) were compared with men who did not. Data were analysed using Poisson regression, adjusted for smoking, occupational exposure, atopy and age.

Results

Exposed men who had participated in accident related tasks had higher prevalence of lower airway symptoms after 5.5 years (n = 24 [73%]) than non-exposed men (28 [48%]), (adjusted relative risk 1.51 [95% confidence interval 1.07, 2.14]). Among men who participated in accident related tasks FEV₁ decline was 48 mL per year, and 12 mL among men who did not (adjusted difference −34 mL per year [−67 mL, −1 mL]), and at follow-up FEV₁/FVC ratio was 71.4 and 74.2% respectively, (adjusted difference −3.0% [−6.0, 0.0%]).

Conclusion

Residents and workers had more airway symptoms and impaired lung function 5.5 years after an oil tank explosion, most significant for a group of men engaged in firefighting and clean-up of pollution after the accident. Public health authorities should be aware of long-term consequences after such accidents.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0357-3) contains supplementary material, which is available to authorized users.

Lung Function Trajectories in World Trade Center-Exposed New York City Firefighters Over 13 Years: The Roles of Smoking and Smoking Cessation

BACKGROUND

World Trade Center (WTC)-exposed Fire Department of the City of New York firefighters lost, on average, 10% of lung function after September 11, 2011, and >10% developed new obstructive airways disease. There was little recovery (on average) over the first 6 years. Follow-up into the next decade allowed us to determine the longer-term exposure effects and the roles of cigarette smoking and cessation on lung function trajectories.

METHODS

We examined serial measurements of FEV1 from March 11, 2000, to September 10, 2014, among 10,641 WTC-exposed Fire Department of the City of New York firefighters with known smoking and body weight histories.

RESULTS

The median number of FEV1 measurements during follow-up was 9; 15% of firefighters arrived at the WTC during the morning of September 11, 2001; and 65% never smoked. Firefighters arriving the morning of September 11, 2001 averaged lower lung function than did lesser exposed firefighters; this difference remained significant during most of follow-up (P < .05). Never smokers had significantly better lung function than current smokers; former smokers fell in between, depending upon their cessation date. Those arriving the morning of September 11, 2001 were more likely to have an FEV1 < lower limits of normal compared with those arriving between September 13, 2001, and September 24, 2001 (OR = 1.70, P < .01). Current smokers were more likely to have an FEV1 < lower limits of normal compared with never smokers (OR = 2.06, P < .01), former smokers who quit before September 11, 2001 (OR = 1.96, P < .01), or those who quit between September 11, 2001 and March 10, 2008 (OR = 1.49, P < .01).

CONCLUSIONS

Thirteen years after September 11, 2001, most firefighters continued to show a lack of lung function recovery, with the trajectory of decline differing by WTC exposure and smoking status. Unlike the immutable effect of WTC exposure, we demonstrated the benefit on lung function of smoking cessation in this unique occupational/environmental cohort.

The Vital Capacity Is Vital: Epidemiology and Clinical Significance of the Restrictive Spirometry Pattern

Epidemiologic research has revealed a substantial portion of the general population with abnormal spirometry results that are characterized by decreased FEV1 and FVC but a preserved FEV1/FVC ratio. This restrictive spirometry pattern (RSP) is inconsistently defined in the literature and not well addressed by current guidelines; there is an accumulating body of evidence, however, that RSP is prevalent to a similar degree as airflow obstruction. Genetic and other risk factors for RSP, such as inhalational injuries and early life exposures, continue to be actively described. Although it seems that RSP is closely associated with the metabolic syndrome, diabetes, and systemic inflammation, it is not a simple marker of obesity. RSP is associated with adverse cardiovascular outcomes, as well as mortality, and it may be an underappreciated cause of functional impairments and respiratory symptoms. Improvement in outcomes in this population will require that clinicians have an appreciation for the significance of this spirometry pattern; additional research into the clinical and radiologic phenotype of these subjects is also needed. This article provides an overview of the recent developments in our understanding of this prevalent and highly morbid spirometry pattern.

Factors associated with poor control of 9/11-related asthma 10-11 years after the 2001 World Trade Center terrorist attacks

Objective: To identify key factors associated with poor asthma control among adults in the World Trade Center (WTC) Health Registry, a longitudinal study of rescue/recovery workers and community members who were directly exposed to the 2001 WTC terrorist attacks and their aftermath. Methods: We studied incident asthma diagnosed by a physician from 12 September 2001 through 31 December 2003 among participants aged ≥18 on 11 September 2001, as reported on an enrollment (2003–2004) or follow-up questionnaire. Based on modified National Asthma Education and Prevention Program criteria, asthma was considered controlled, poorly-controlled, or very poorly-controlled at the time of a 2011–2012 follow-up questionnaire. Probable post-traumatic stress disorder, depression, and generalized anxiety disorder were defined using validated scales. Self-reported gastroesophageal reflux symptoms (GERS) and obstructive sleep apnea (OSA) were obtained from questionnaire responses. Multinomial logistic regression was used to examine factors associated with poor or very poor asthma control. Results: Among 2445 participants, 33.7% had poorly-controlled symptoms and 34.6% had very poorly-controlled symptoms in 2011–2012. Accounting for factors including age, education, body mass index, and smoking, there was a dose–response relationship between the number of mental health conditions and poorer asthma control. Participants with three mental health conditions had five times the odds of poor control and 13 times the odds of very poor control compared to participants without mental health comorbidities. GERS and OSA were significantly associated with poor or very poor control. Conclusions: Rates of poor asthma control were very high in this group with post-9/11 diagnosed asthma. Comprehensive care of 9/11-related asthma should include management of mental and physical health comorbidities.

YKL-40 is a Protective Biomarker for Fatty Liver in World Trade Center Particulate Matter-Exposed Firefighters

Background

Serum biomarkers of metabolic syndrome predict abnormal lung function in World Trade Center particulate matter (WTC-PM)-exposed Fire Department of New York (FDNY) rescue workers. In animal models, exposure to ambient PM induces non-alcoholic fatty liver disease (NAFLD), a well-known comorbidity of metabolic syndrome. YKL-40 is an inflammatory biomarker for both liver and lung disease. We tested if YKL-40 is a biomarker for NAFLD in this dust-exposed cohort.

Methods

Using a nested case-control design, we studied 131 FDNY personnel who had Computer Tomography performed within 5 years post 9/11. NAFLD was defined by a liver/spleen attenuation ratio of ≤1. Serum biomarkers, lipid panel and liver function were measured in serum that had been drawn within 6 months of September 11, 2001. YKL-40 and chitotriosidase were assayed by ELISA. We tested biomarker and NAFLD association using logistic regression adjusted for age, BMI, and post-911 lung function.

Results

NAFLD was present in 29/131 (22%) of the cohort. In a multivariable model increasing YKL-40 was protective while increasing triglyceride and alkaline phosphatase were risk factors for NAFLD.

Conclusions

Increased YKL-40 is a protective biomarker in non-alcoholic fatty liver disease. Further studies may reveal a link between PM-induced lung and liver diseases.

Change in lung function over time in male metropolitan firefighters and general population controls: a 3-year follow-up study

OBJECTIVES

Previous studies in firefighters have been contradictory regarding their course of lung function over time. The aim of this ongoing study is to investigate how changes in lung function over time in male metropolitan firefighters compare with those in population controls, and to explore associations between firefighters' use of personal respiratory protection devices during occupational exposures and their risk of accelerated lung function decline.

METHODS

A prospective comparison of FEV1 (forced expiratory volume in 1 second) and FVC (forced vital capacity) was performed between 281 firefighters and 933 population controls. Logistic regression models were used to compare changes from baseline of FEV1 and FVC after 3 years and risk of accelerated decline between the cohorts. Within the firefighter cohort, risk of accelerated decline was compared between subgroups based on use of respiratory protection devices.

RESULTS

Controls showed similar mean annual declines for FEV1 and FVC across age categories, whereas firefighters aged <45 years showed increasing values over time (p=0.040). Firefighters had a lower odds of accelerated FEV1 decline compared with controls (OR=0.60, 95%CI 110.44; 0.83), but firefighters who never or rarely used respiratory protection during fire knockdown had a higher odds of accelerated FEV1 decline compared with those who used it often or frequently (OR=2.20, 95%CI 1.02; 4.74).

CONCLUSIONS

Younger generations of firefighters showed an increase in lung function relative to older colleagues, while population controls consistently showed decline of lung function across all ages. Firefighters who reported to be incompliant in using respiratory protection showed an increased risk of accelerated FEV1 decline.

Cancer incidence in world trade center rescue and recovery workers, 2001-2008

BACKGROUND

World Trade Center (WTC) rescue and recovery workers were exposed to a complex mix of pollutants and carcinogens.

OBJECTIVE

The purpose of this investigation was to evaluate cancer incidence in responders during the first 7 years after 11 September 2001.

METHODS

Cancers among 20,984 consented participants in the WTC Health Program were identified through linkage to state tumor registries in New York, New Jersey, Connecticut, and Pennsylvania. Standardized incidence ratios (SIRs) were calculated to compare cancers diagnosed in responders to predicted numbers for the general population. Multivariate regression models were used to estimate associations with degree of exposure.

RESULTS

A total of 575 cancers were diagnosed in 552 individuals. Increases above registry-based expectations were noted for all cancer sites combined (SIR = 1.15; 95% CI: 1.06, 1.25), thyroid cancer (SIR = 2.39; 95% CI: 1.70, 3.27), prostate cancer (SIR = 1.21; 95% CI: 1.01, 1.44), combined hematopoietic and lymphoid cancers (SIR = 1.36; 95% CI: 1.07, 1.71), and soft tissue cancers (SIR = 2.26; 95% CI: 1.13, 4.05). When restricted to 302 cancers diagnosed ≥ 6 months after enrollment, the SIR for all cancers decreased to 1.06 (95% CI: 0.94, 1.18), but thyroid and prostate cancer diagnoses remained greater than expected. All cancers combined were increased in very highly exposed responders and among those exposed to significant amounts of dust, compared with responders who reported lower levels of exposure.

CONCLUSION

Estimates should be interpreted with caution given the short follow-up and long latency period for most cancers, the intensive medical surveillance of this cohort, and the small numbers of cancers at specific sites. However, our findings highlight the need for continued follow-up and surveillance of WTC responders.

Epidemiology of Respiratory Health Outcomes Among World Trade Center Disaster Workers: Review of the Literature 10 Years After the September 11, 2001 Terrorist Attacks

Tens of thousands of workers participated in rescue, recovery, and cleanup activities at the World Trade Center (WTC) site in lower Manhattan after the terrorist attacks on September 11, 2001 (9/11). The collapse of the WTC resulted in the release of a variety of airborne toxicants. To date, respiratory symptoms and diseases have been among the most examined health outcomes in studies of WTC disaster workers. A systematic review of the literature on respiratory health outcomes was undertaken to describe the available information on new onset of respiratory symptoms and diseases among WTC disaster workers after September 11, 2001. Independent risk factors for respiratory health outcomes included being caught in the dust and debris cloud, early arrival at the WTC site, longer duration of work, and delaying mask and respirator use. Methodological challenges in epidemiologic studies of WTC disaster workers involved study design, exposure misclassification, and limited information on potential confounders and effect modifiers. In the 10 years after 9/11, epidemiologic studies of WTC disaster workers have been essential in investigating the respiratory health consequences of WTC exposure. Longitudinal studies along with continued medical surveillance will be vital in understanding the long-term respiratory burden associated with occupational WTC exposure. (Disaster Med Public Health Preparedness. 2011;5:S189–S196)

Longitudinal spirometry among patients in a treatment program for community members with World Trade Center-related illness

OBJECTIVE

The course of lung function in community members exposed to World Trade Center (WTC) dust and fumes remains undefined. We studied longitudinal spirometry among patients in the WTC Environmental Health Center (WTCEHC) treatment program.

METHODS

Observational study of 946 WTCEHC patients with repeated spirometry measures analyzed on the population as a whole and stratified by smoking status, initial spirometry pattern, and WTC-related exposure category.

RESULTS

Improvement in forced vital capacity (54.4 mL/yr; 95% confidence interval, 45.0 to 63.8) and forced expiratory volume in 1 second (36.8 mL/yr; 95% confidence interval, 29.3 to 44.3) was noted for the population as a whole. Heavy smokers did not improve. Spirometry changes differed depending on initial spirometry pattern and exposure category.

CONCLUSION

These data demonstrate spirometry improvement in select populations suggesting reversibility in airway injury and reinforcing the importance of continued treatment.

Exposure, probable PTSD and lower respiratory illness among World Trade Center rescue, recovery and clean-up workers

BACKGROUND

Thousands of rescue and recovery workers descended on the World Trade Center (WTC) in the wake of the terrorist attack of September 11, 2001 (9/11). Recent studies show that respiratory illness and post-traumatic stress disorder (PTSD) are the hallmark health problems, but relationships between them are poorly understood. The current study examined this link and evaluated contributions of WTC exposures.

METHOD

Participants were 8508 police and 12 333 non-traditional responders examined at the WTC Medical Monitoring and Treatment Program (WTC-MMTP), a clinic network in the New York area established by the National Institute for Occupational Safety and Health (NIOSH). We used structural equation modeling (SEM) to explore patterns of association among exposures, other risk factors, probable WTC-related PTSD [based on the PTSD Checklist (PCL)], physician-assessed respiratory symptoms arising after 9/11 and present at examination, and abnormal pulmonary functioning defined by low forced vital capacity (FVC).

RESULTS

Fewer police than non-traditional responders had probable PTSD (5.9% v. 23.0%) and respiratory symptoms (22.5% v. 28.4%), whereas pulmonary function was similar. PTSD and respiratory symptoms were moderately correlated (r=0.28 for police and 0.27 for non-traditional responders). Exposure was more strongly associated with respiratory symptoms than with PTSD or lung function. The SEM model that best fit the data in both groups suggested that PTSD statistically mediated the association of exposure with respiratory symptoms.

CONCLUSIONS

Although longitudinal data are needed to confirm the mediation hypothesis, the link between PTSD and respiratory symptoms is noteworthy and calls for further investigation. The findings also support the value of integrated medical and psychiatric treatment for disaster responders.

Case-control study of lung function in World Trade Center Health Registry area residents and workers

RATIONALE

Residents and area workers who inhaled dust and fumes from the World Trade Center disaster reported lower respiratory symptoms in two World Trade Center Health Registry surveys (2003-2004 and 2006-2007), but lung function data were lacking.

OBJECTIVES

To examine the relationship between persistent respiratory symptoms and pulmonary function in a nested case-control study of exposed adult residents and area workers 7-8 years after September 11, 2001.

METHODS

Registrants reporting post September 11th onset of a lower respiratory symptom in the first survey and the same symptom in the second survey were solicited as potential cases. Registrants without lower respiratory symptoms in either Registry survey were solicited as potential control subjects. Final case-control status was determined by lower respiratory symptoms at a third interview (the study), when spirometry and impulse oscillometry were also performed.

MEASUREMENTS AND MAIN RESULTS

We identified 180 cases and 473 control subjects. Cases were more likely than control subjects to have abnormal spirometry (19% vs. 11%; P < 0.05), and impulse oscillometry measurements of elevated airway resistance (R5; 68% vs. 27%; P < 0.0001) and frequency dependence of resistance (R₅₋₂₀; 36% vs. 7%; P < 0.0001). When spirometry was normal, cases were more likely than control subjects to have elevated R₅ and R₅₋₂₀ (62% vs. 25% and 27% vs. 6%, respectively; both P < 0.0001). Associations between symptoms and oscillometry held when factors significant in bivariate comparisons (body mass index, spirometry, and exposures) were analyzed using logistic regression.

CONCLUSIONS

This study links persistent respiratory symptoms and oscillometric abnormalities in World Trade Center-exposed residents and area workers. Elevated R₅ and R₅₋₂₀ in cases despite normal spirometry suggested distal airway dysfunction as a mechanism for symptoms.

Exposure science for terrorist attacks and theaters of military conflict: minimizing contact with toxicants

The strategies for protecting our deployed U.S. Forces are outlined in National Research Council documents published in 1999-2000. This article summarizes experiences and information gathered and interpreted regarding population and rescue workers' exposures in the aftermath of the 2001 World Trade Center attacks, with the aim to provide insights on issues related to military deployment to locations with hazardous agents. Issues covered include phases of exposure, materials of concern, detection equipment, and personal protection equipment. The focus is on human exposure issues, which are primarily associated with strategies 1 through 3 of the National Research Council's report entitled "Protecting Those Who Serve: Strategies to Protect the Health of Deployed U.S. Forces". Contact and duration of contact with hazardous substances are critical areas of concern, which require prevention and intervention procedures and protocols to reduce the incidence of acute and long-term health outcomes.

World Trade Center Health Registry--a model for a nanomaterials exposure registry

OBJECTIVE

To describe the development of and some of the early results from the World Trade Center Health Registry (WTCHR). Is the WTCHR a model for a nanomaterials exposure registry? What lessons may be learned from the WTCHR?

METHODS

We describe the steps involved in creation of the WTCHR, from design through implementation.

RESULTS

The lessons learned from the WTCHR include thorough documentation of exposure early in the registry, using multimode surveys to maximize response rate, establishing an institutional home with sufficient resources for core as well as in-depth longitudinal and intervention studies, meeting with stakeholders regularly, making data accessible, and timely publication of findings, including wide dissemination of clinical guidelines.

CONCLUSIONS

The process of creating and maintaining the WTCHR provides important lessons for the possible creation of a nanomaterials exposure registry.

Short-term and medium-term health effects of 9/11

The New York City terrorist attacks on Sept 11, 2001 (9/11), killed nearly 2800 people and thousands more had subsequent health problems. In this Review of health effects in the short and medium terms, strong evidence is provided for associations between experiencing or witnessing events related to 9/11 and post-traumatic stress disorder and respiratory illness, with a correlation between prolonged, intense exposure and increased overall illness and disability. Rescue and recovery workers, especially those who arrived early at the World Trade Center site or worked for longer periods, were more likely to develop respiratory illness than were other exposed groups. Risk factors for post-traumatic stress disorder included proximity to the site on 9/11, living or working in lower Manhattan, rescue or recovery work at the World Trade Center site, event-related loss of spouse, and low social support. Investigators note associations between 9/11 exposures and additional disorders, such as depression and substance use; however, for some health problems association with exposures related to 9/11 is unclear.

World Trade Center disaster: assessment of responder occupations, work locations, and job tasks

BACKGROUND

To date there have been no comprehensive reports of the work performedby 9/11 World Trade Center responders.

METHODS

18,969 responders enrolled in the WTC Medical Monitoring and Treatment Program were used to describe workers’ pre-9/11 occupations, WTC work activities and locations from September 11, 2001 to June 2002.

RESULTS

The most common pre-9/11 occupation was protective services (47%); other common occupations included construction, telecommunications, transportation, and support services workers. 14% served as volunteers. Almost one-half began work on 9/11 and >80% reported working on or adjacent to the ‘‘pile’’ at Ground Zero. Initially,the most common activity was search and rescue but subsequently, the activities of most responders related to their pre-9/11 occupations. Other major activities included security; personnel support; buildings and grounds cleaning; and telecommunications repair.

CONCLUSIONS

The spatial, temporal, occupational, and task-related taxonomy reported here will aid the development of a job-exposure matrix, assist in assessment of disease risk, and improve planning and training for responders in future urban disasters.

Occupational lower airway disease in relation to World Trade Center inhalation exposure

PURPOSE OF REVIEW

To summarize the knowledge about the occupational lower airway diseases that seem related to exposures at the World Trade Center disaster site.

RECENT FINDINGS

Those diseases have been characterized as irritant-induced asthma, chronic nonspecific bronchitis, chronic bronchiolitis/small airway disease, and aggravated preexistent chronic obstructive lung disease (most frequently chronic obstructive pulmonary disease, but also asthma), with the expected overlapping features among them. One remarkable characteristic of the irritant-induced asthma observed among these workers was the slow onset of symptoms and long delay in clinical diagnoses.

SUMMARY

Longitudinal studies suggest that both the incidence and the associated functional decline of these predominantly obstructive lung diseases stabilized several years ago, but longer follow-up is clearly necessary.

Unusual ciliary abnormalities in three 9/11 response workers

After the 9/11 terrorist attacks on the World Trade Center in New York in 2001, thousands of response workers were exposed to complex mixtures of toxins, pollutants, and carcinogens. Many developed illnesses involving the respiratory tract. We report unusual ultrastructural ciliary abnormalities in 3 response workers that corresponded to their respiratory and ciliary functional abnormalities. Each patient had respiratory cilia biopsies that were evaluated for motility and ultrastructural changes. Impaired ciliary motility was seen in 2 of the 3 patients. Each of the patients showed monomorphic ultrastructural abnormalities. Two of the patients showed identical triangular disarray of axonemal microtubules with peripheral doublets 1,4, and 7 forming the corners of the triangle and doublet 9 always more medially displaced than doublets 2, 3, 5, 6, and 8. Two workers had cilia in which axonemes were replaced by homogeneously dense cores. One of these also had cilia with triangular axonemes as previously described. The other had cilia with a geometric triangular to pentagonal shape. The ciliary abnormalities described here may represent a new class of primary ciliary dyskinesia in which abnormalities may have a genetic basis and a phenotypic expression that is prompted at the cellular level by local environmental conditions.

"Sarcoid like" granulomatous pulmonary disease in World Trade Center disaster responders

BACKGROUND

More than 20,000 responders have been examined through the World Trade Center (WTC) Medical Monitoring and Treatment Program since September 11, 2001. Studies on WTC firefighters have shown elevated rates of sarcoidosis. The main objective of this study was to report the incidence of "sarcoid like" granulomatous pulmonary disease in other WTC responders.

METHODS

Cases of sarcoid like granulomatous pulmonary disease were identified by: patient self-report, physician report and ICD-9 codes. Each case was evaluated by three pulmonologists using the ACCESS criteria and only "definite" cases are reported.

RESULTS

Thirty-eight patients were classified as "definite" cases. Six-year incidence was 192/100,000. The peak annual incidence of 54 per 100,000 person-years occurred between 9/11/2003 and 9/11/2004. Incidence in black responders was nearly double that of white responders. Low FVC was the most common spirometric abnormality.

CONCLUSIONS

Sarcoid like granulomatous pulmonary disease is present among the WTC responders. While the incidence is lower than that reported among firefighters, it is higher than expected.

Emerging exposures and respiratory health: World Trade Center dust

The attack on the World Trade Center (WTC) on 9/11/2001 produced a massive dust cloud with acute exposure, and the rubble pile burning over 3 months exposed more than 300,000 residents, rescue workers, and clean-up workers. Firefighters in the New York City Fire Department had significant respiratory symptoms characterized by cough, dyspnea, gastroesophageal reflux, and nasal stuffiness with a significant 1-year decline in FVC and FEV(1). Bronchial hyperreactivity measured by methacholine challenge correlated with bronchial wall thickening on CT scans. Compared with the NHANES III data for FVC and FEV(1), 32% of 2,000 WTC dust-exposed residents and clean-up workers were below the lower 5th percentile. The most common abnormality was a low FVC pattern, a finding similar to that also described for individuals in rescue and recovery activities. Among those complaining of respiratory symptoms and normal spirometry, almost half had abnormalities detected with impedance oscillometry consistent with distal airways' disease. Follow-up with the WTC Health Registry and the WTC Environmental Health Center will help discern whether treatment with anti-inflammatory medications or bronchodilators in those with respiratory symptoms may prevent the development of chronic obstructive pulmonary disease.

Accelerated spirometric decline in New York City firefighters with α₁-antitrypsin deficiency

BACKGROUND

On September 11, 2001, the World Trade Center (WTC) collapse caused massive air pollution, producing variable amounts of lung function reduction in the New York City Fire Department (FDNY) rescue workforce. α₁-Antitrypsin (AAT) deficiency is a risk factor for obstructive airway disease.

METHODS

This prospective, longitudinal cohort study of the first 4 years post-September 11, 2001, investigated the influence of AAT deficiency on adjusted longitudinal spirometric change (FEV₁) in 90 FDNY rescue workers with WTC exposure. Workers with protease inhibitor (Pi) Z heterozygosity were considered moderately AAT deficient. PiS homozygosity or PiS heterozygosity without concomitant PiZ heterozygosity was considered mild deficiency, and PiM homozygosity was considered normal. Alternately, workers had low AAT levels if serum AAT was ≤ 20 μmol/L.

RESULTS

In addition to normal aging-related decline (37 mL/y), significant FEV(1) decline accelerations developed with increasing AAT deficiency severity (110 mL/y for moderate and 32 mL/y for mild) or with low AAT serum levels (49 mL/y). Spirometric rates pre-September 11, 2001, did not show accelerations with AAT deficiency. Among workers with low AAT levels, cough persisted in a significant number of participants at 4 years post-September 11, 2001.

CONCLUSIONS

FDNY rescue workers with AAT deficiency had significant spirometric decline accelerations and persistent airway symptoms during the first 4 years after WTC exposure, representing a novel gene-by-environment interaction. Clinically meaningful decline acceleration occurred even with the mild serum AAT level reductions associated with PiS heterozygosity (without concomitant PiZ heterozygosity).

Occupational asthma and lower airway disease among World Trade Center workers and volunteers

The World Trade Center (WTC) disaster and its recovery work involved a range of hazardous occupational exposures that have not been fully characterized but can be reasonably assumed to have the potential to cause mucosal inflammation in the upper and lower airways. A high prevalence of lower airway disease (LAD) symptoms was reported by several early surveys. Clinical studies further categorized the diagnoses as irritant-induced asthma (of subacute onset), nonspecific chronic bronchitis, chronic bronchiolitis, or aggravated preexistent obstructive pulmonary disease in a substantial proportion of patients. Risk factors for WTC-related LAD included early (on September 11 or 12, 2001) arrival at the WTC site and work at the pile of the collapsed towers. Cigarette smoking (but not atopy) also seemed to be a risk factor for LAD. No data thus far suggest an increased incidence of neoplastic or interstitial lung disease, but ongoing surveillance is clearly necessary.

Lung function in rescue workers at the World Trade Center after 7 years

BACKGROUND

The terrorist attacks on the World Trade Center on September 11, 2001, exposed thousands of Fire Department of New York City (FDNY) rescue workers to dust, leading to substantial declines in lung function in the first year. We sought to determine the longer-term effects of exposure.

METHODS

Using linear mixed models, we analyzed the forced expiratory volume in 1 second (FEV(1)) of both active and retired FDNY rescue workers on the basis of spirometry routinely performed at intervals of 12 to 18 months from March 12, 2000, to September 11, 2008.

RESULTS

Of the 13,954 FDNY workers who were present at the World Trade Center between September 11, 2001, and September 24, 2001, a total of 12,781 (91.6%) participated in this study, contributing 61,746 quality-screened spirometric measurements. The median follow-up was 6.1 years for firefighters and 6.4 years for emergency-medical-services (EMS) workers. In the first year, the mean FEV(1) decreased significantly for all workers, more for firefighters who had never smoked (a reduction of 439 ml; 95% confidence interval [CI], 408 to 471) than for EMS workers who had never smoked (a reduction of 267 ml; 95% CI, 263 to 271) (P<0.001 for both comparisons). There was little or no recovery in FEV(1) during the subsequent 6 years, with a mean annualized reduction in FEV(1) of 25 ml per year for firefighters and 40 ml per year for EMS workers. The proportion of workers who had never smoked and who had an FEV(1) below the lower limit of the normal range increased during the first year, from 3% to 18% for firefighters and from 12% to 22% for EMS workers, stabilizing at about 13% for firefighters and 22% for EMS workers during the subsequent 6 years.

CONCLUSIONS

Exposure to World Trade Center dust led to large declines in FEV(1) for FDNY rescue workers during the first year. Overall, these declines were persistent, without recovery over the next 6 years, leaving a substantial proportion of workers with abnormal lung function.

Obstructive airways disease with air trapping among firefighters exposed to World Trade Center dust

BACKGROUND

The World Trade Center (WTC) collapse produced a massive exposure to respirable particulates in New York City Fire Department (FDNY) rescue workers. This group had spirometry examinations pre-September 11, 2001, and post-September 11, 2001, demonstrating declines in lung function with parallel declines in FEV(1) and FVC. To date, the underlying pathophysiologic cause for this has been open to question.

METHODS

Of 13,234 participants in the FDNY-WTC Monitoring Program, 1,720 (13%) were referred for pulmonary subspecialty evaluation at a single institution. Evaluation included 919 full pulmonary function tests, 1,219 methacholine challenge tests, and 982 high-resolution chest CT scans.

RESULTS

At pulmonary evaluation (median 34 months post-September 11, 2001), median values were FEV(1) 93% predicted (interquartile range [IQR], 83%-101%), FVC 98% predicted (IQR, 89%-106%), and FEV(1)/FVC 0.78 (IQR, 0.72-0.82). The residual volume (RV) was 123% predicted (IQR, 106%-147%) with nearly all participants having normal total lung capacity, functional residual capacity, and diffusing capacity of carbon monoxide. Also, 1,051/1,720 (59%) had obstructive airways disease based on at least one of the following: FEV(1)/FVC, bronchodilator responsiveness, hyperreactivity, or elevated RV. After adjusting for age, gender, race, height and weight, and tobacco use, the decline in FEV(1) post-September 11, 2001, was significantly correlated with increased RV percent predicted (P < .0001), increased bronchodilator responsiveness (P < .0001), and increased hyperreactivity (P = .0056). CT scans demonstrated bronchial wall thickening that was significantly associated with the decline in FEV(1) post-September 11, 2001 (P = .024), increases in hyperreactivity (P < .0001), and increases in RV (P < .0001). Few had evidence for interstitial disease.

CONCLUSIONS

Airways obstruction was the predominant physiologic finding underlying the reduction in lung function post-September 11, 2001, in FDNY WTC rescue workers presenting for pulmonary evaluation.