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

Biomarkers of Airway Disease, Barrett's and Underdiagnosed Reflux Noninvasively (BAD-BURN) in World Trade Center exposed firefighters: a case-control observational study protocol

BACKGROUND

Particulate matter exposure (PM) is a cause of aerodigestive disease globally. The destruction of the World Trade Center (WTC) exposed first responders and inhabitants of New York City to WTC-PM and caused obstructive airways disease (OAD), gastroesophageal reflux disease (GERD) and Barrett's Esophagus (BE). GERD not only diminishes health-related quality of life but also gives rise to complications that extend beyond the scope of BE. GERD can incite or exacerbate allergies, sinusitis, bronchitis, and asthma. Disease features of the aerodigestive axis can overlap, often necessitating more invasive diagnostic testing and treatment modalities. This presents a need to develop novel non-invasive biomarkers of GERD, BE, airway hyperreactivity (AHR), treatment efficacy, and severity of symptoms.

METHODS

Our observational case-cohort study will leverage the longitudinally phenotyped Fire Department of New York (FDNY)-WTC exposed cohort to identify Biomarkers of Airway Disease, Barrett's and Underdiagnosed Reflux Noninvasively (BAD-BURN). Our study population consists of n = 4,192 individuals from which we have randomly selected a sub-cohort control group (n = 837). We will then recruit subgroups of i. AHR only ii. GERD only iii. BE iv. GERD/BE and AHR overlap or v. No GERD or AHR, from the sub-cohort control group. We will then phenotype and examine non-invasive biomarkers of these subgroups to identify under-diagnosis and/or treatment efficacy. The findings may further contribute to the development of future biologically plausible therapies, ultimately enhance patient care and quality of life.

DISCUSSION

Although many studies have suggested interdependence between airway and digestive diseases, the causative factors and specific mechanisms remain unclear. The detection of the disease is further complicated by the invasiveness of conventional GERD diagnosis procedures and the limited availability of disease-specific biomarkers. The management of reflux is important, as it directly increases risk of cancer and negatively impacts quality of life. Therefore, it is vital to develop novel noninvasive disease markers that can effectively phenotype, facilitate early diagnosis of premalignant disease and identify potential therapeutic targets to improve patient care.

TRIAL REGISTRATION

Name of Primary Registry: "Biomarkers of Airway Disease, Barrett's and Underdiagnosed Reflux Noninvasively (BADBURN)". Trial Identifying Number: NCT05216133 . Date of Registration: January 31, 2022.

Normal Lung Function and Mortality in World Trade Center Responders and National Health and Nutrition Examination Survey III Participants

Rationale: Low FEV1 is a biomarker of increased mortality. The association of normal lung function and mortality is not well described. Objectives: To evaluate the FEV1-mortality association among participants with normal lung function. Methods: A total of 10,999 Fire Department of the City of New York (FDNY) responders and 10,901 Third National Health and Nutrition Examination Survey (NHANES III) participants, aged 18-65 years with FEV1 ⩾80% predicted, were analyzed, with FEV1 percent predicted calculated using Global Lung Function Initiative Global race-neutral reference equations. Mortality data were obtained from linkages to the National Death Index. Cox proportional hazards models estimated the association between FEV1 and all-cause mortality, controlling for age, sex, race/ethnicity, smoking history, and, for FDNY, work assignment. Cohorts were followed for a maximum of 20.3 years. Measurements and Main Results: We observed 504 deaths (4.6%) of 10,999 for FDNY and 1,237 deaths (9.4% [weighted]) of 10,901 for NHANES III. Relative to FEV1 ⩾120% predicted, mortality was significantly higher for FEV1 100-109%, 90-99%, and 80-89% predicted in the FDNY cohort. In the NHANES III cohort, mortality was significantly higher for FEV1 90-99% and 80-89% predicted. Each 10% higher predicted FEV1 was associated with 15% (hazard ratio, 0.85; 95% confidence interval, 0.80-0.91) and 23% (hazard ratio, 0.77; 95% confidence interval, 0.71-0.84) lower mortality for FDNY and NHANES III, respectively. Conclusions: In both cohorts, higher FEV1 is associated with lower mortality, suggesting higher FEV1 is a biomarker of better health. These findings demonstrate that a single cross-sectional measurement of FEV1 is predictive of mortality over two decades, even when FEV1 is in the normal range.

Biomarkers of Airway Disease, Barrett's and Underdiagnosed Reflux Noninvasively (BAD-BURN): a Case-Control Observational Study Protocol

BACKGROUND

Particulate matter exposure (PM) is a cause of aerodigestive disease globally. The destruction of the World Trade Center (WTC) exposed fifirst responders and inhabitants of New York City to WTC-PM and caused obstructive airways disease (OAD), gastroesophageal Refux disease (GERD) and Barrett's Esophagus (BE). GERD not only diminishes health-related quality of life but also gives rise to complications that extend beyond the scope of BE. GERD can incite or exacerbate allergies, sinusitis, bronchitis, and asthma. Disease features of the aerodigestive axis can overlap, often necessitating more invasive diagnostic testing and treatment modalities. This presents a need to develop novel non-invasive biomarkers of GERD, BE, airway hyperreactivity (AHR), treatment efficacy, and severity of symptoms.

METHODS

Our observational case-cohort study will leverage the longitudinally phenotyped Fire Department of New York (FDNY)-WTC exposed cohort to identify Biomarkers of Airway Disease, Barrett's and Underdiagnosed Refux Noninvasively (BAD-BURN). Our study population consists of n = 4,192 individuals from which we have randomly selected a sub-cohort control group (n = 837). We will then recruit subgroups of i. AHR only ii. GERD only iii. BE iv. GERD/BE and AHR overlap or v. No GERD or AHR, from the sub-cohort control group. We will then phenotype and examine non-invasive biomarkers of these subgroups to identify under-diagnosis and/or treatment efficacy. The findings may further contribute to the development of future biologically plausible therapies, ultimately enhance patient care and quality of life.

DISCUSSION

Although many studies have suggested interdependence between airway and digestive diseases, the causative factors and specific mechanisms remain unclear. The detection of the disease is further complicated by the invasiveness of conventional GERD diagnosis procedures and the limited availability of disease-specific biomarkers. The management of Refux is important, as it directly increases risk of cancer and negatively impacts quality of life. Therefore, it is vital to develop novel noninvasive disease markers that can effectively phenotype, facilitate early diagnosis of premalignant disease and identify potential therapeutic targets to improve patient care.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05216133; January 18, 2022.

Association of firefighting exposures with lung function using a novel job exposure matrix (JEM)

OBJECTIVES

Characterisation of firefighters' exposures to dangerous chemicals in smoke from non-wildfire incidents, directly through personal monitoring and indirectly from work-related records, is scarce. The aim of this study was to evaluate the association between smoke particle exposures (P) and pulmonary function.

METHODS

The study period spanned from January 2010 through September 2021. Routine firefighting P were estimated using fire incident characteristics, response data and emission factors from a novel job exposure matrix. Linear mixed effects modelling was employed to estimate changes in pulmonary function as measured by forced expiratory volume in one second (FEV1). Models controlled for age, race/ethnicity, height, smoking and weight.

RESULTS

Every 1000 kg P was associated with 13 mL lower FEV1 (β=-13.34; 95% CI=-13.98 to -12.70) over the entire 12-year follow-up period. When analysing exposures within 3 months before PFT measurements, 1000 kg P was associated with 27 mL lower FEV1 (β=-26.87; 95% CI=-34.54 to -19.20). When evaluating P estimated within 3 months of a pulmonary function test (PFT), stronger associations were observed among those most highly exposed to the World Trade Center (WTC) disaster (β=-12.90; 95% CI=-22.70 to -2.89); the association of cumulative exposures was similar for both highly and less highly exposed individuals.

DISCUSSION

Smoke particle exposures were observed to have modest short-term and long-term associations with pulmonary function, particularly in those who, previously, had high levels of WTC exposure. Future work examining the association between P and pulmonary function among non-WTC exposed firefighters will be essential for disentangling the effects of ageing, routine firefighting and WTC exposures.

Cluster Analysis of World Trade Center Related Lower Airway Diseases

ABSTRACT

Introduction: Cluster analysis can classify without a priori assumptions the heterogeneous chronic lower airway diseases found in former workers at the World Trade Center (WTC) disaster site. Methods: We selected the first available chest computed tomography scan with quantitative computed tomography measurements on 311 former WTC workers with complete clinical, and spirometric data from their closest surveillance visit. We performed a nonhierarchical iterative algorithm K-prototype cluster analysis, using gap measure. Results: A five-cluster solution was most satisfactory. Cluster 5 had the healthiest individuals. In cluster 4, smoking was most prevalent and intense but there was scant evidence of respiratory disease. Cluster 3 had symptomatic subjects with reduced forced vital capacity impairment (low FVC). Clusters 1 and 2 had less dyspneic subjects, but more functional and quantitative computed tomography evidence of chronic obstructive pulmonary disease (COPD) in cluster 1, or low FVC in cluster 2. Clusters 1 and 4 had the highest proportion of rapid first-second forced expiratory volume decliners. Conclusions: Cluster analysis confirms low FVC and COPD/pre-COPD as distinctive chronic lower airway disease phenotypes on long-term surveillance of the WTC workers.

Association of Lung Function Decline with All-Cause and Cancer-Cause Mortality after World Trade Center Dust Exposure

Rationale: In numerous cohorts, lung function decline is associated with all-cause and cardiovascular-cause mortality, but the association between the decrease in forced expiratory volume in 1 second (FEV1) and cancer-cause mortality, particularly after occupational/environmental exposure(s), is unclear. Exposure to dust/smoke from the World Trade Center (WTC) disaster caused inflammation and lung injury in Fire Department of the City of New York rescue/recovery workers. In addition, prior research found that >10% of the cohort experienced greater than twice the age-related decrease in FEV1 (⩾64 ml/yr). Objectives: To evaluate the association of longitudinal lung function with all-cause and cancer-cause mortality after exposure to the WTC disaster. Methods: We conducted a prospective cohort study using longitudinal prebronchodilator FEV1 data for 12,264 WTC-exposed firefighters and emergency medical service providers. All-cause and cancer-cause mortality were ascertained using National Death Index data from September 12, 2001, through December 31, 2021. Joint longitudinal survival models evaluated the association of baseline FEV1 and change in FEV1 from baseline with all-cause and cancer-cause mortality adjusted for age, race/ethnicity, height, smoking, work assignment (firefighters vs. emergency medical service providers), and WTC exposure. Results: By December 31, 2021, 607 of the 12,264 individuals in the cohort (4.9%) had died (crude rate = 259.5 per 100,000 person-years), and 190 of 12,264 (1.5%) had died from cancer (crude rate = 81.2 per 100,000 person-years). Baseline FEV1 was ⩾80% predicted in 10,970 of the 12,264 (89.4%); final FEV1 was ⩾80% in 9,996 (81.5%). Lower FEV1 at baseline was associated with greater risk for all-cause mortality (hazard ratio [HR] per liter = 2.32; 95% confidence interval [95% CI] = 1.98-2.72) and cancer-cause mortality (HR per liter = 1.99; 95% CI = 1.49-2.66). Longitudinally, each 100-ml/yr decrease in FEV1 was associated with an 11% increase in all-cause mortality (HR = 1.11; 95% CI = 1.06-1.15) and a 7% increase in cancer-cause mortality (HR = 1.07; 95% CI = 1.00-1.15). Compared with FEV1 decrease <64 ml/yr, those with FEV1 decrease ⩾64 ml/yr had higher all-cause (HR = 2.91; 95% CI = 2.37-3.56) and cancer-cause mortality (HR = 2.68; 95% CI = 1.90-3.79). Conclusions: Baseline FEV1 and longitudinal FEV1 decrease are associated with increased risk of all-cause and cancer-cause mortality in a previously healthy occupational cohort, the majority of whom had normal lung function, after intense exposure to dust/smoke. Further investigation is needed to define pathways by which lung function impacts mortality after an irritant exposure.

The World Trade Center Health Program: Smoking cessation

Cigarette smoking can cause and/or worsen a variety of health conditions. The U.S. Preventive Services Task Force (USPSTF) recommends that smoking cessation services be offered to all adults who currently smoke, and governmental and non-governmental professional organizations support providing these interventions to patients who smoke. The World Trade Center (WTC) Health Program, a federal program that provides health monitoring and treatment to those directed exposed to the September 11, 2001 terrorist attacks, provides smoking cessation therapy for eligible members. This paper identifies treatment strategies for smoking cessation and references the treatment coverage policy in the WTC Health Program. In addition, this paper notes the higher smoking prevalence among those with mental health conditions such as posttraumatic stress disorder (PTSD), and the need for heightened cessation efforts given the lower quit success rates among such persons.

Comparing self-reported obstructive airway disease in firefighters with and without World Trade Center exposure

BACKGROUND

The degree to which routine, non-World Trade Center (WTC) firefighting exposures contribute to the WTC exposure-obstructive airway disease (OAD) relationship is unknown. Our objective was to compare the frequency of self-reported OAD diagnoses in WTC-exposed firefighters from the Fire Department of the City of New York (FDNY) compared with non-WTC-exposed firefighters from other cities and the general population.

METHODS

A total of 9792 WTC-exposed male FDNY firefighters and 3138 non-WTC-exposed male firefighters from Chicago, Philadelphia, and San Francisco who were actively employed on 9/11/01 and completed a health questionnaire were included. Logistic regression estimated odds ratios of self-reported asthma and COPD diagnoses in firefighters (WTC-exposed vs. non-WTC-exposed; all firefighters vs. general population), adjusting for age, race, smoking status, and last medical visit.

RESULTS

WTC-exposed firefighters were, on average, younger on 9/11 (mean ± SD = 40.2 ± 7.4 vs. 44.1 ± 9.1) and less likely to report ever-smoking (32.9% vs. 41.8%) than non-WTC-exposed firefighters. Odds of any OAD and asthma were 4.5 and 6.3 times greater, respectively, in WTC-exposed versus non-WTC-exposed. Odds of COPD were also greater in WTC-exposed versus non-WTC-exposed, particularly among never-smokers. Compared with the general population, WTC-exposed firefighters had greater odds of both asthma and COPD, while the nonexposed had lower odds of asthma and greater odds of COPD.

CONCLUSIONS

Odds ratios for OAD diagnoses were greater in WTC-exposed firefighters versus both non-WTC-exposed and the general population after adjusting for covariates. While asthma and other OADs are known occupational hazards of firefighting, WTC exposure significantly compounded these adverse respiratory effects.

Comparation of predictive value of CAT and change in CAT in the short term for future exacerbation of chronic obstructive pulmonary disease

PURPOSE

Our study aimed to compare the predictive value of the COPD Assessment Test (CAT) score at baseline and short-term change in CAT for future exacerbations in chronic obstructive pulmonary disease (COPD) patients.

METHODS

This was a multicentre prospective study. Patients with COPD were recruited into the study and followed up for one year. CAT score and exacerbation in the previous year were collected at baseline. Change in CAT was defined as CAT score changing between baseline and the 6-month follow-up. Exacerbation was recorded during the one-year follow-up from 0^th to 12^th month.

RESULT

A total of 536 patients were enrolled for final analysis. The mean baseline CAT score was 14.5 ± 6.6 and the median (IQR) change in CAT was -2 (8). On Cox regression analysis, baseline CAT score, change in CAT and history of exacerbation were independent risk factors for exacerbation in the one-year follow-up. Compared with the r value of correlation between baseline CAT score and frequency of exacerbations during the one-year follow-up (r = 0.286, p < .001), that correlation between the change in CAT and frequency of exacerbations during follow-up was higher (r = 0.421, p < .001). The receiver operating characteristic (ROC) curves showed that change in CAT had a better predictive capacity for future exacerbation than baseline CAT (0.789 versus 0.609, p = .001). The ROC showed that change in CAT also had a better predictive capacity for future exacerbation than exacerbation in the previous year (0.789 versus 0.689, p = .011).

CONCLUSION

The correlation between baseline CAT score and future exacerbation was weak, however, the correlation between change in CAT and future exacerbation was moderate. Change in CAT in the short term had a better predictive value for future exacerbations of COPD than baseline CAT and exacerbation in the previous year.

World Trade Center Health Program best practices for diagnosing and treating chronic obstructive pulmonary disease

World Trade Center exposures may have the potential to cause or aggravate chronic obstructive pulmonary disease (COPD). The WTC Health Program covers the entire range of clinical services for COPD, following the 2021 diagnostic and treatment guidelines of the Global Initiative for Chronic Obstructive Lung Disease (GOLD).

Clinical features, prognostic factors, and survival of patients with antisynthetase syndrome and interstitial lung disease

Objective

This study aimed to analyze the clinical features and prognostic factors of imaging progression and survival in patients with antisynthetase syndrome (ASS) complicated by interstitial lung disease (ILD) in a large Chinese cohort.

Methods

Medical records, imaging, and serological data of 111 patients with ASS-ILD (positive for at least one of the following autoantibodies: anti-Jo1, anti-PL7, anti-PL12, and anti-EJ) from the Affiliated Yantai Yuhuangding Hospital of Qingdao University database were retrospectively investigated. According to the changes in high-resolution computed tomography (HRCT) outcomes at 1 year follow-up, Patients were categorized into three groups: the regression, stability, and deterioration groups. Univariate analysis was performed to evaluate the possible prognostic factors of ILD outcome and death, and multivariate analysis was performed to determine the independent predictors of ASS-ILD outcome and death by logistic regression.

Results

The number of CD3-CD19+ cells and initial glucocorticoid dosage were correlated with imaging progression, and may be independent risk factors for ILD deterioration. Dyspnea as the first symptom, hypohemoglobinemia, the serum ferritin level, oxygen partial pressure at diagnosis, and different treatment types were important factors affecting survival, and the initial serum ferritin level may be an independent risk factor for survival.

Conclusions

The clinical characteristics of patients with ASS-ILD with different antisynthetase antibody subtypes are different. An increase in the CD3-CD19+ cell level is an independent risk factor for the deterioration of HRCT imaging. Early intensive treatment with high-dose glucocorticoids can effectively improve imaging prognosis of ILD. Patients with significantly elevated serum ferritin levels should be treated intensively.

Longitudinal Changes in Spirometry in Deployed Air Force Firefighters

INTRODUCTION

Inhalational exposures are common among service members who deploy to southwest Asia. The objective of this study is to determine if deployed Air Force firefighters have any decline in spirometry related to deployment.

METHODS

This study is a retrospective chart review.

RESULTS

The database search identified 302 firefighters with documentation of two separate spirometry examinations. For deployed firefighters, mean change in forced expiratory volume at 1 second (FEV1) percent predicted was -1.01 ± 7.86, forced vital capacity (FVC) was -0.46 ± 10.26 predicted, and mid-expiratory flow (FEF25-75) was -0.13 ± 12.97. For firefighters who had never deployed, mean change in FEV1 percent predicted was +0.08 ± 7.09, FVC was +0.72 ± 7.75, and FEF25-75 was -0.66 ± 16.17.

CONCLUSION

There does not appear to be evidence that deployment causes a significant change in lung function as measured by spirometry.

Fine Particulate Matter and Lung Function among Burning-Exposed Deepwater Horizon Oil Spill Workers

BACKGROUND

During the 2010 Deepwater Horizon (DWH) disaster, controlled burning was conducted to remove oil from the water. Workers near combustion sites were potentially exposed to increased fine particulate matter [with aerodynamic diameter ≤2.5μm (PM2.5)] levels. Exposure to PM2.5 has been linked to decreased lung function, but to our knowledge, no study has examined exposure encountered in an oil spill cleanup.

OBJECTIVE

We investigated the association between estimated PM2.5 only from burning/flaring of oil/gas and lung function measured 1-3 y after the DWH disaster.

METHODS

We included workers who participated in response and cleanup activities on the water during the DWH disaster and had lung function measured at a subsequent home visit (n=2,316). PM2.5 concentrations were estimated using a Gaussian plume dispersion model and linked to work histories via a job-exposure matrix. We evaluated forced expiratory volume in 1 s (FEV1; milliliters), forced vital capacity (FVC; milliliters), and their ratio (FEV1/FVC; %) in relation to average and cumulative daily maximum exposures using multivariable linear regressions.

RESULTS

We observed significant exposure-response trends associating higher cumulative daily maximum PM2.5 exposure with lower FEV1 (p-trend=0.04) and FEV1/FVC (p-trend=0.01). In comparison with the referent group (workers not involved in or near the burning), those with higher cumulative exposures had lower FEV1 [-166.8mL, 95% confidence interval (CI): -337.3, 3.7] and FEV1/FVC (-1.7, 95% CI: -3.6, 0.2). We also saw nonsignificant reductions in FVC (high vs. referent: -120.9, 95% CI: -319.4, 77.6; p-trend=0.36). Similar associations were seen for average daily maximum PM2.5 exposure. Inverse associations were also observed in analyses stratified by smoking and time from exposure to spirometry and when we restricted to workers without prespill lung disease.

CONCLUSIONS

Among oil spill workers, exposure to PM2.5 specifically from controlled burning of oil/gas was associated with significantly lower FEV1 and FEV1/FVC when compared with workers not involved in burning. https://doi.org/10.1289/EHP8930.

Health effects following exposure to dust from the World Trade Center disaster: An update

Exposure to dust, smoke, and fumes containing volatile chemicals and particulate matter (PM) from the World Trade Center (WTC) towers' collapse impacted thousands of citizens and first responders (FR; firefighters, medicals staff, police officers) of New York City. Surviving FR and recovery workers are increasingly prone to age-related diseases that their prior WTC dust exposures might expedite or make worse. This review provides an overview of published WTC studies concerning FR/recovery workers' exposure and causal mechanisms of age-related disease susceptibility, specifically those involving the cardiopulmonary and neurological systems. This review also highlights the recent findings of the major health effects of cardiovascular, pulmonary, and neurological health sequelae from WTC dust exposure. To better treat those that risked their lives during and after the disaster of September 11, 2001, the deleterious mechanisms that WTC dust exposure exerted and continue to exert on the heart, lungs, and brain of FR must be better understood.

Dynamic Metabolic Risk Profiling of World Trade Center Lung Disease: A Longitudinal Cohort Study

Rationale: Metabolic syndrome (MetSyn) increases the risk of World Trade Center (WTC) lung injury (LI). However, the temporal relationship of MetSyn, exposure intensity, and lung dysfunction is not well understood. Objective: To model the association of longitudinal MetSyn characteristics with WTC lung disease to define modifiable risk. Methods: Firefighters, for whom consent was obtained (N = 5,738), were active duty on September 11, 2001 (9/11). WTC-LI (n = 1,475; FEV₁% predicted <lower limit of normal [LLN]) and non-WTC-LI (n = 4,263; FEV₁% predicted ⩾LLN at all exams) was the primary outcome, and FVC% predicted <LLN and FEV₁/FVC <0.70 were secondary outcomes. We assessed 1) the effect of concurrent MetSyn on longitudinal lung function by linear mixed models, 2) the temporal effect of MetSyn and exposure by Weibull proportional hazards, 3) the effects of MetSyn's rate of change by two-stage models, and 4) the nonlinear joint effect of longitudinal MetSyn components by a partially linear single-index model (PLSI). Measurements and Main Results: WTC-LI cases were more often ever-smokers, arrived in the morning (9/11), and had MetSyn. Body mass index ⩾30 kg/m² and high-density lipoprotein <40 mg/dl were most contributory to concurrent loss of FEV₁% predicted and FVC% predicted while conserving FEV₁/FVC. Body mass index ⩾30 kg/m² and dyslipidemia significantly predicted WTC-LI, FVC% predicted <LLN in a Weibull proportional hazards model. Dynamic risk assessment of WTC-LI on the basis of MetSyn and exposure showed how reduction of MetSyn factors further reduces WTC-LI likelihood in susceptible populations. PLSI demonstrates that MetSyn has a nonlinear relationship with WTC lung disease, and increases in cumulative MetSyn risk factors exponentially increase WTC-LI risk. An interactive metabolic-risk modeling application was developed to simplify PLSI interpretation. Conclusions: MetSyn and WTC exposure contribute to the development of lung disease. Dynamic risk assessment may be used to encourage treatment of MetSyn in susceptible populations. Future studies will focus on dietary intervention as a disease modifier.

Lung function decline before and after treatment of World Trade Center associated obstructive airways disease with inhaled corticosteroids and long-acting beta agonists

Background

Greater than average loss of one‐second forced expiratory volume (FEV₁) is a risk factor for asthma, chronic obstructive pulmonary disease (COPD), and asthma/COPD overlap syndrome in World Trade Center (WTC)‐exposed firefighters. Inhaled corticosteroids and long‐acting beta agonists (ICS/LABA) are used to treat obstructive airways disease but their impact on FEV₁‐trajectory in this population is unknown.

Methods

The study population included WTC‐exposed male firefighters who were treated with ICS/LABA for 2 years or longer (with initiation before 2015), had at least two FEV₁ measurements before ICS/LABA initiation and two FEV₁ measurements posttreatment between September 11, 2001 and September 10, 2019. Linear mixed‐effects models were used to estimate FEV₁‐slope pre‐ and post‐treatment.

Results

During follow‐up, 1023 WTC‐exposed firefighters were treated with ICS/LABA for 2 years or longer. When comparing intervals 6 years before and 6 years after treatment, participants had an 18.7 ml/year (95% confidence interval [CI]: 11.3–26.1) improvement in FEV₁‐slope after adjustment for baseline FEV₁, race, height, WTC exposure, weight change, blood eosinophil concentration, and smoking status. After stratification by median date of ICS/LABA initiation (January 14, 2010), earlier ICS/LABA‐initiators had a 32.5 ml/year (95% CI: 19.5–45.5) improvement in slope but later ICS/LABA‐initiators had a nonsignificant FEV₁‐slope improvement (7.9 ml/year, 95% CI: −0.5 to 17.2).

Conclusions

WTC‐exposed firefighters treated with ICS/LABA had improved FEV₁ slope after initiation, particularly among those who started earlier. Treatment was, however, not associated with FEV₁‐slope improvement if started after the median initiation date (1/14/2010), likely because onset of disease began before treatment initiation. Research on alternative treatments is needed for patients with greater than average FEV₁‐decline who have not responded to ICS/LABA.

PTSD symptoms, depressive symptoms, and subjective cognitive concerns in WTC-exposed and non-WTC-exposed firefighters

BACKGROUND

Firefighting has been associated with posttraumatic stress disorder (PTSD) and other mental health conditions. We previously found that among Fire Department of the City of New York (FDNY) responders to the World Trade Center (WTC) disaster, higher-intensity WTC-exposure predicted PTSD symptoms, depressive symptoms, and subjective cognitive concerns. The present study aims to compare these symptoms in the FDNY WTC-exposed cohort versus a comparison cohort of non-FDNY, non-WTC-exposed firefighters.

METHODS

The study population included WTC-exposed male firefighters from FDNY (N = 8466) and non-WTC-exposed male firefighters from Chicago (N = 1195), Philadelphia (N = 770), and San Francisco (N = 650) fire departments who were employed on 9/11/2001 and completed a health questionnaire between 3/1/2018 and 12/31/2020. Current PTSD symptoms, depressive symptoms, and subjective cognitive concerns were assessed via validated screening instruments. Multivariable linear regression analyses stratified by fire department estimated the impact of covariates on each outcome.

RESULTS

Adjusted mean PTSD symptom scores ranged from 23.5 ± 0.6 in Chicago firefighters to 25.8 ± 0.2 in FDNY, and adjusted mean depressive symptom scores ranged from 7.3 ± 0.5 in Chicago to 9.4 ± 0.6 in Philadelphia. WTC-exposure was associated with fewer subjective cognitive concerns (β = -0.69 ± 0.05, p < .001) after controlling for covariates. Across cohorts, older age was associated with more cognitive concerns, but fewer PTSD and depressive symptoms.

CONCLUSIONS

WTC-exposed firefighters had fewer cognitive concerns compared with non-WTC-exposed firefighters. We were unable to estimate associations between WTC exposure and PTSD symptoms or depressive symptoms due to variability between non-WTC-exposed cohorts. Longitudinal follow-up is needed to assess PTSD, depressive, and cognitive symptom trajectories in firefighter populations as they age.

Serum Th-2 cytokines and FEV1 decline in WTC-exposed firefighters: A 19-year longitudinal study

Background

Accelerated‐FEV₁‐decline, defined as rate of decline in FEV₁ > 64 ml/year, is a risk factor for asthma and chronic obstructive pulmonary disease in World Trade Center (WTC)‐exposed firefighters. Accelerated‐FEV₁‐decline in this cohort is associated with elevated blood eosinophil concentrations, a mediator of Th‐2 response. We hypothesized that an association exists between Th‐2 biomarkers and FEV₁ decline rate in those with accelerated‐FEV₁‐decline.

Methods

Serum was drawn from Fire Department of the City of New York (FDNY) firefighters 1–6 months (early) (N = 816) and 12–13 years (late) (N = 983) after 9/11/2001. Th‐2 biomarkers IL‐4, IL‐13, and IL‐5 were assayed by multiplex Luminex. Individual FEV₁ decline rates were calculated using spirometric measurements taken: (1) between 9/11/2001 and 9/10/2020 for the early biomarker group and (2) between late measurement date and 9/10/2020 for the late biomarker group. Associations of early and late Th‐2 biomarkers with subsequent FEV₁ decline rates were analyzed using multivariable linear regression controlling for demographics, smoking status, and other potential confounders.

Results

In WTC‐exposed firefighters with accelerated‐FEV₁‐decline, IL‐4, IL‐13, and IL‐5 measured 1–6 months post‐9/11/2001 were associated with greater FEV₁ decline ml/year between 9/11/2001 and 9/10/2020 (−2.9 ± 1.4 ml/year per IL‐4 doubling; −8.4 ± 1.2 ml/year per IL‐13 doubling; −7.9 ± 1.3 ml/year per IL‐5 doubling). Among late measured Th‐2 biomarkers, only IL‐4 was associated with subsequent FEV₁ decline rate (−4.0 ± 1.6 ml/year per IL‐4 doubling).

Conclusions

In WTC‐exposed firefighters with accelerated‐FEV₁‐decline, elevated serum IL‐4 measured both 1–6 months and 12–13 years after 9/11 is associated with greater FEV₁ decline/year. Drugs targeting the IL‐4 pathway may improve lung function in this high‐risk subgroup.

Two Weeks of Smoking Cessation Reverse Cigarette Smoke-Induced Skeletal Muscle Atrophy and Mitochondrial Dysfunction in Mice

INTRODUCTION

Apart from its adverse effects on the respiratory system, cigarette smoking also induces skeletal muscle atrophy and dysfunction. Whether short-term smoking cessation can restore muscle mass and function is unknown. We, therefore, studied the impact of 1- and 2-week smoking cessation on skeletal muscles in a mouse model.

METHODS

Male mice were divided into four groups: Air-exposed (14 weeks); cigarette smoke (CS)-exposed (14 weeks); CS-exposed (13 weeks) followed by 1-week cessation; CS-exposed (12 weeks) followed by 2 weeks cessation to examine exercise capacity, physical activity levels, body composition, muscle function, capillarization, mitochondrial function and protein expression in the soleus, plantaris, and diaphragm muscles.

RESULTS

CS-induced loss of body and muscle mass was significantly improved within 1 week of cessation due to increased lean and fat mass. Mitochondrial respiration and protein levels of the respiratory complexes in the soleus were lower in CS-exposed mice, but similar to control values after 2 weeks of cessation. Exposing isolated soleus muscles to CS extracts reduced mitochondrial respiration that was reversed after removing the extract. While physical activity was reduced in all groups, exercise capacity, limb muscle force, fatigue resistance, fiber size and capillarization, and diaphragm cytoplasmic HIF-1α were unaltered by CS-exposure. However, CS-induced diaphragm atrophy and increased capillary density were not seen after 2 weeks of smoking cessation.

CONCLUSION

In male mice, 2 weeks of smoking cessation reversed smoking-induced mitochondrial dysfunction, limb muscle mass loss, and diaphragm muscle atrophy, highlighting immediate benefits of cessation on skeletal muscles.

IMPLICATIONS

Our study demonstrates that CS-induced skeletal muscle mitochondrial dysfunction and atrophy are significantly improved by 2 weeks of cessation in male mice. We show for the first time that smoking cessation as short as 1 to 2 weeks is associated with immediate beneficial effects on skeletal muscle structure and function with the diaphragm being particularly sensitive to CS-exposure and cessation. This could help motivate smokers to quit smoking as early as possible. The knowledge that smoking cessation has potential positive extrapulmonary effects is particularly relevant for patients referred to rehabilitation programs and those admitted to hospitals suffering from acute or chronic muscle deterioration yet struggling with smoking cessation.

Dietary phenotype and advanced glycation end-products predict WTC-obstructive airways disease: a longitudinal observational study

BACKGROUND

Diet is a modifier of metabolic syndrome which in turn is associated with World Trade Center obstructive airways disease (WTC-OAD). We have designed this study to (1) assess the dietary phenotype (food types, physical activity, and dietary habits) of the Fire Department of New York (FDNY) WTC-Health Program (WTC-HP) cohort and (2) quantify the association of dietary quality and its advanced glycation end product (AGE) content with the development of WTC-OAD.

METHODS

WTC-OAD, defined as developing WTC-Lung Injury (WTC-LI; FEV1 < LLN) and/or airway hyperreactivity (AHR; positive methacholine and/or positive bronchodilator response). Rapid Eating and Activity Assessment for Participants-Short Version (REAP-S) deployed on 3/1/2018 in the WTC-HP annual monitoring assessment. Clinical and REAP-S data of consented subjects was extracted (7/17/2019). Diet quality [low-(15-19), moderate-(20-29), and high-(30-39)] and AGE content per REAP-S questionnaire were assessed for association with WTC-OAD. Regression models adjusted for smoking, hyperglycemia, hypertension, age on 9/11, WTC-exposure, BMI, and job description.

RESULTS

N = 9508 completed the annual questionnaire, while N = 4015 completed REAP-S and had spirometry. WTC-OAD developed in N = 921, while N = 3094 never developed WTC-OAD. Low- and moderate-dietary quality, eating more (processed meats, fried foods, sugary drinks), fewer (vegetables, whole-grains),and having a diet abundant in AGEs were significantly associated with WTC-OAD. Smoking was not a significant risk factor of WTC-OAD.

CONCLUSIONS

REAP-S was successfully implemented in the FDNY WTC-HP monitoring questionnaire and produced valuable dietary phenotyping. Our observational study has identified low dietary quality and AGE abundant dietary habits as risk factors for pulmonary disease in the context of WTC-exposure. Dietary phenotyping, not only focuses our metabolomic/biomarker profiling but also further informs future dietary interventions that may positively impact particulate matter associated lung disease.

World Trade Center Health Program: First Decade of Research

The terrorist attacks on 11 September 2001 placed nearly a half million people at increased risk of adverse health. Health effects research began shortly after and continues today, now mostly as a coordinated effort under the federally mandated World Trade Center (WTC) Health Program (WTCHP). Established in 2011, the WTCHP provides medical monitoring and treatment of covered health conditions for responders and survivors and maintains a research program aimed to improve the care and well-being of the affected population. By 2020, funds in excess of USD 127 M had been awarded for health effects research. This review describes research findings and provides an overview of the WTCHP and its future directions. The literature was systematically searched for relevant articles published from 11 September 2001 through 30 June 2020. Synthesis was limited to broad categories of mental health, cancer, respiratory disease, vulnerable populations, and emerging conditions. In total, 944 WTC articles were published, including peer-reviewed articles funded by the WTCHP (n = 291) and other sources. Research has focused on characterizing the burden and etiology of WTC-related health conditions. As the program moves forward, translational research that directly enhances the care of individuals with chronic mental and physical health conditions is needed.

PTSD and Depressive Symptoms as Potential Mediators of the Association between World Trade Center Exposure and Subjective Cognitive Concerns in Rescue/Recovery Workers

We observed that World Trade Center (WTC) exposure, post-traumatic stress disorder (PTSD) symptoms and depressive symptoms were associated with subjective cognitive concerns in Fire Department of the City of New York (FDNY) rescue/recovery workers. This follow-up study examined whether PTSD symptoms and/or depressive symptoms mediate the observed association between WTC exposure and subjective cognitive concerns. We included WTC-exposed FDNY workers who completed the Cognitive Function Instrument (CFI), measuring self-perceived cognitive decline (N = 9516). PTSD symptoms and depressive symptoms were assessed using the PCL-S and CES-D, respectively. Multivariable linear regression estimated the association between WTC exposure and CFI score, adjusting for confounders. Mediation analyses followed the methods of Vanderweele (2014). Participants’ average age at CFI assessment was 56.6 ± 7.6 years. Higher-intensity WTC exposure was associated with worse CFI score, an effect that was entirely mediated by PTSD symptoms (%mediated: 110.9%; 95%CI: 83.1–138.9). When substituting depressive symptoms for PTSD symptoms, the WTC exposure–CFI association was largely mediated (%mediated: 82.1%; 95%CI: 60.6–103.7). Our findings that PTSD symptoms and depressive symptoms mediate the association between WTC exposure and subjective cognitive concerns indicate that in the absence of these symptoms, WTC exposure in rescue/recovery workers would not be associated with subjective cognition. Interventions targeting PTSD and depression may have additional value in mitigating cognitive decline in WTC-exposed populations.

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.

Modified and simplified clinically important deterioration: multidimensional indices of short-term disease trajectory to predict future exacerbations in patients with chronic obstructive pulmonary disease

BACKGROUND AND AIMS

Various prediction indices based on the single time point observation have been proposed in chronic obstructive pulmonary disease (COPD), but little was known about disease trajectory as a predictor of future exacerbations. Our study explored the association between disease trajectory and future exacerbations, and validated the predictive value of the modified and simplified short-term clinically important deterioration (CID).

METHODS

This study was a multicenter, prospective observational study. Patients with COPD were recruited into our study and followed up for 18 months. The modified CID (CID-C) was defined as a decrease of 100 mL in forced expiratory volume in 1 second (FEV1), or suffering exacerbations, or increase of 2 units in COPD Assessment Test (CAT) during the first 6 months follow-up. Simplified CID was defined when excluding CAT from the CID-C model.

RESULTS

A total of 127 patients were enrolled in our final analysis. Compared with patients without exacerbations during the period of the 6th to the 18th month, patients with exacerbations were more likely to have frequent short-term exacerbations in the first 6 months (2.14 versus 0.21, p < 0.001). The short-term exacerbations were the best predictor for future exacerbations [odds ratio (OR): 13.25; 95% confidence interval: 5.62-34.67; p < 0.001], followed by the history of exacerbation before study entry, short-term changes in FEV1 and CAT. CID-C and Simplified CID were both significantly associated with exacerbations (OR: 7.14 and 9.74, both p < 0.001). The receiver operating characteristic curves showed that the Simplified CID had slightly better predictive capacity for future exacerbation than CID-C (0.754 versus 0.695, p = 0.02).

CONCLUSION

Disease trajectory, including both the CID-C and the Simplified CID had significant predictive value for future exacerbations.The reviews of this paper are available via the supplemental material section.

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.

Antisynthetase syndrome pathogenesis: knowledge and uncertainties

PURPOSE OF REVIEW

Antisynthetase syndrome (ASyS) is an acquired myopathy characterized by the presence of myositis-specific autoantibodies directed against tRNA-synthetases. ASyS is potentially life threatening due to lung involvement and treatment remains a challenge to date. With symptoms not limited to muscles but also involving lung, skin and joints, ASyS appears specific and has a particular pathogenesis, different from the other inflammatory myopathies. This review is intended to discuss the current understanding of ASyS pathogenesis, pointing its current knowledge and also the crucial prospects that may lead to critical improvement of ASyS care.

RECENT FINDINGS

Regarding ASyS pathogenesis, initiation of the disease seems to arise in a multifactorial context, with first lesions occurring within the lungs. This may lead to aberrant self-antigen exposure and tolerance breakdown. The consequences are abnormal activation of both innate and adaptive immunity, resulting in the patients with favourable genetic background to autoimmune-mediated organ lesions. Immune and nonimmune roles of the antigen, as well as antigen presentation leading to specific T-cell and B-cell activation and to the production of specific autoantibodies belong to the disease process.

SUMMARY

This work aims to detail ASyS pathogenesis understanding, from initiation to the disease propagation and target tissue lesions, in order to considering future treatment directions.

Environmental Exposures and Asthma in Active Duty Service Members

PURPOSE OF REVIEW

Reports of respiratory symptoms, including asthma and hyper-reactive airway disease, have been more numerous in the media and medical literature since active duty service members (SM) began to support campaigns in South West Asia (SWA). Numerous environmental exposures have been reported and this review assesses the available evidence surrounding exposures, confounding conditions, and attempts to develop screening mechanisms.

RECENT FINDINGS

While particulate matter exposures and particularly exposure to burn pits have garnered much attention, a 2010 Armed Forces Health Surveillance Center report and 2011 Institute of Medicine publication did not identify a link between exposure to particulate matter with SM respiratory disease. The "Study of Active Duty Military for Pulmonary Disease related to Environmental Deployment Exposure," (STAMPEDE) and STAMPEDE II have not identified effective forms of routine screening and these and other sources point to the importance of other factors in SM respiratory disease. These include higher than anticipated rates of tobacco use in deployed settings, impacts of obesity, recurrence of childhood asthma, and of confounding conditions such as Paradoxical Vocal Fold Motion. As with the general population, a complex set of clinical inputs and environmental exposures surround asthma and similar respiratory processes in SM. Concrete relationships and mechanisms for assessment continue to be assessed and refined, but clear associations and pathways have remained elusive.

Validation of Predictive Metabolic Syndrome Biomarkers of World Trade Center Lung Injury: A 16-Year Longitudinal Study

BACKGROUND

Metabolic syndrome (MetSyn) predicted future development of World Trade Center lung injury (WTC-LI) in a subgroup of firefighters who never smoked and were male. An intracohort validation of MetSyn as a predictor of WTC-LI is examined in the cohort exposed to the World Trade Center (WTC) that has been followed longitudinally for 16 years.

METHODS

Results of pulmonary function tests (n = 98,221) in workers exposed to the WTC (n = 9,566) were evaluated. A baseline cohort of firefighters who had normal FEV1 before 9/11 and who had had serum drawn before site closure on July 24, 2002 (n = 7,487) was investigated. Case subjects with WTC-LI (n = 1,208) were identified if they had at least two measured instances of FEV1 less than the lower limit of normal (LLN). Cox proportional hazards modeled early MetSyn biomarker ability to predict development of FEV1 less than the LLN.

RESULTS

Case subjects were more likely to smoke, be highly exposed, and have MetSyn. There was a significant exposure dose response; the individuals most highly exposed had a 30.1% increased risk of developing WTC-LI, having MetSyn increased risk of developing WTC-LI by 55.7%, and smoking increased risk by 15.2%. There was significant interaction between smoking and exposure.

CONCLUSIONS

We validated the usefulness of MetSyn to predict future WTC-LI in a larger population of individuals who were exposed. MetSyn defined by dyslipidemia, insulin resistance, and cardiovascular disease suggests that systemic inflammation can contribute to future lung function loss.

Review of the British Thoracic Society Winter Meeting 2018, 5-7 December 2018, London, UK

INTRODUCTION

The Winter Meeting of the British Thoracic Society (BTS) is a platform for the latest clinical and scientific research in respiratory medicine. This review summarises some key symposia and presentations from the BTS Winter Meeting 2018.

METHODS

Key symposia and research presentations from the BTS Winter Meeting 2018 were attended and reviewed by the authors.

RESULTS

The seminal messages from the latest clinical and scientific research covering a range of respiratory diseases, including asthma, interstitial lung disease, infection, cystic fibrosis, pulmonary vascular disease, pleural disease and occupational lung disease were summarised in this review.

DISCUSSION

The BTS Winter Meeting 2018 brought the very best of respiratory research to an audience of scientists, physicians, nurses and allied health professionals. The Winter Meeting continues to be a highlight of the UK respiratory research calendar, and we look forward to the next meeting in December 2019.

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.

Abnormalities on Chest Computed Tomography and Lung Function Following an Intense Dust Exposure: A 17-Year Longitudinal Study

Fire Department of the City of New York (FDNY) firefighters experienced intense dust exposure working at the World Trade Center (WTC) site on and after 11/9/2001 (9/11). We hypothesized that high-intensity WTC exposure caused abnormalities found on chest computed tomography (CT). Between 11/9/2001–10/9/2018, 4277 firefighters underwent a clinically-indicated chest CT. Spirometric measurements and symptoms were recorded during routine medical examinations. High-intensity exposure, defined as initial arrival at the WTC on the morning of 9/11, increased the risk of bronchial wall thickening, emphysema, and air trapping. Early post-9/11 symptoms of wheeze and shortness of breath were associated with bronchial wall thickening, emphysema, and air trapping. The risk of accelerated forced expiratory volume at one second (FEV₁) decline (>64 mL/year decline) increased with bronchial wall thickening and emphysema, but decreased with air trapping. The risk of airflow obstruction also increased with bronchial wall thickening and emphysema but decreased with air trapping. In a previously healthy occupational cohort, high-intensity WTC exposure increased the risk for CT abnormalities. Bronchial wall thickening and emphysema were associated with respiratory symptoms, accelerated FEV₁ decline, and airflow obstruction. Air trapping was associated with respiratory symptoms, although lung function was preserved. Physiologic differences between CT abnormalities suggest that distinct types of airway injury may result from a common exposure.

Metabolic Syndrome Biomarkers of World Trade Center Airway Hyperreactivity: A 16-Year Prospective Cohort Study

Airway hyperreactivity (AHR) related to environmental exposure is a significant public health risk worldwide. Similarly, metabolic syndrome (MetSyn), a risk factor for obstructive airway disease (OAD) and systemic inflammation, is a significant contributor to global adverse health. This prospective cohort study followed N = 7486 World Trade Center (WTC)-exposed male firefighters from 11 September 2001 (9/11) until 1 August 2017 and investigated N = 539 with newly developed AHR for clinical biomarkers of MetSyn and compared them to the non-AHR group. Male firefighters with normal lung function and no AHR pre-9/11 who had blood drawn from 9 September 2001–24 July 2002 were assessed. World Trade Center-Airway Hyperreactivity (WTC-AHR) was defined as either a positive bronchodilator response (BDR) or methacholine challenge test (MCT). The electronic medical record (EMR) was queried for their MetSyn characteristics (lipid profile, body mass index (BMI), glucose), and routine clinical biomarkers (such as complete blood counts). We modeled the association of MetSyn characteristics at the first post-9/11 exam with AHR. Those with AHR were significantly more likely to be older, have higher BMIs, have high intensity exposure, and have MetSyn. Smoking history was not associated with WTC-AHR. Those present on the morning of 9/11 had 224% increased risk of developing AHR, and those who arrived in the afternoon of 9/11 had a 75.9% increased risk. Having ≥3 MetSyn parameters increased the risk of WTC-AHR by 65.4%. Co-existing MetSyn and high WTC exposure are predictive of future AHR and suggest that systemic inflammation may be a contributor.

The long-term rate of change in lung function in urban professional firefighters: a systematic review

BACKGROUND

Despite the known occupational hazards, it is not yet clear whether long-term career firefighting leads to a greater rate of decline in lung function than would normally be expected, and how this rate of change is affected by firefighting exposures and other risk/protective factors.

METHODS

A systematic search of online electronic databases was conducted to identify longitudinal studies reporting on the rate of change in the forced expiratory volume in one second (FEV1) of forced vital capacity (FVC). Included studies were critically appraised to determine their risk of bias using the Research Triangle Institute Item Bank (RTI-IB) on Risk of Bias and Precision of Observational Studies.

RESULTS

Twenty-two studies were identified for inclusion, from four different countries, published between 1974 and 2016. Examined separately, studies were categorised by the type of firefighting exposure. Firefighters experienced variable rates of decline in lung function, which were particularly influenced by cigarette smoking. The influence of routine firefighting exposures is unclear and limited by the methods of measurement, while firefighters exposed to 'non-routine' severe exposures unanimously experienced accelerated declines.

CONCLUSIONS

The data provided by longitudinal studies provide an unclear picture of how the rate of change in lung function of firefighters relates to routine exposures and how it compares to the rate of change expected in a working-age population. Non-smoking firefighters who routinely wear respiratory protection are more likely than otherwise to have a normal rate of decline in lung function. Exposure to catastrophic events significantly increases the rate of decline in firefighter lung function but there is limited evidence detailing the effect of routine firefighting. Future studies will benefit from more robust methods of measuring exposure.

TRIAL REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO), registration number ( CRD42017058499 ).

Predictors of Asthma/COPD Overlap in FDNY Firefighters With World Trade Center Dust Exposure: A Longitudinal Study

BACKGROUND

Previously healthy firefighters with World Trade Center (WTC) dust exposure developed airway disease. Risk factors for irritant-associated asthma/COPD overlap are poorly defined.

METHODS

This study included 2,137 WTC-exposed firefighters who underwent a clinically indicated bronchodilator pulmonary function test (BD-PFT) between 9/11/2001 and 9/10/2017. A post-BD FEV₁ increase of > 12% and 200 mL from baseline defined asthma, and a post-BD FEV₁/FVC ratio < 0.7 identified COPD cases. Participants who met both criteria had asthma/COPD overlap. Eosinophil levels were measured on screening blood tests performed shortly after 9/11/2001 and prior to BD-PFT; a subgroup of participants also had serum IgE and 21 cytokines measured (n = 215). Marginal Cox regression models for multiple events assessed the associations of eosinophil levels or serum biomarkers with subsequent diagnosis, with age, race, smoking, WTC exposure, first post-9/11 FEV₁/FVC ratio, and BMI included as covariates.

RESULTS

BD-PFT diagnosed asthma/COPD overlap in 99 subjects (4.6%), isolated-asthma in 202 (9.5%), and isolated-COPD in 215 (10.1%). Eosinophil concentration ≥ 300 cells/μL was associated with increased risk of asthma/COPD overlap (hazard ratio [HR], 1.85; 95% CI, 1.16-2.95) but not with isolated-asthma or isolated-COPD. Serum IL-4 also predicted asthma/COPD overlap (HR, 1.51 per doubling of cytokine concentration; 95% CI, 1.17-1.95). Greater IL-21 concentration was associated with both isolated-asthma and isolated-COPD (HRs of 1.73 [95% CI, 1.27-2.35] and 2.06 [95% CI, 1.31-3.23], respectively).

CONCLUSIONS

In WTC-exposed firefighters, elevated blood eosinophil and IL-4 levels are associated with subsequent asthma/COPD overlap. Disease-specific T-helper cell type 2 biomarkers present years before diagnosis suggest patient-intrinsic predisposition to irritant-associated asthma/COPD overlap.

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.

Predictive Biomarkers of Gastroesophageal Reflux Disease and Barrett's Esophagus in World Trade Center Exposed Firefighters: a 15 Year Longitudinal Study

Gastroesophageal reflux disease (GERD) and Barrett’s Esophagus (BE), which are prevalent in the World Trade Center (WTC) exposed and general populations, negatively impact quality of life and cost of healthcare. GERD, a risk factor of BE, is linked to obstructive airways disease (OAD). We aim to identify serum biomarkers of GERD/BE, and assess the respiratory and clinical phenotype of a longitudinal cohort of never-smoking, male, WTC-exposed rescue workers presenting with pulmonary symptoms. Biomarkers collected soon after WTC-exposure were evaluated in optimized predictive models of GERD/BE. In the WTC-exposed cohort, the prevalence of BE is at least 6 times higher than in the general population. GERD/BE cases had similar lung function, D_LCO, bronchodilator response and long-acting β-agonist use compared to controls. In confounder-adjusted regression models, TNF-α ≥ 6 pg/mL predicted both GERD and BE. GERD was also predicted by C-peptide ≥ 360 pg/mL, while BE was predicted by fractalkine ≥ 250 pg/mL and IP-10 ≥ 290 pg/mL. Finally, participants with GERD had significantly increased use of short-acting β-agonist compared to controls. Overall, biomarkers sampled prior to GERD/BE presentation showed strong predictive abilities of disease development. This study frames future investigations to further our understanding of aerodigestive pathology due to particulate matter exposure.

Blood Leukocyte Concentrations, FEV1 Decline, and Airflow Limitation. A 15-Year Longitudinal Study of World Trade Center-exposed Firefighters

RATIONALE

Rescue/recovery work at the World Trade Center disaster site (WTC) caused a proximate decline in lung function in Fire Department of the City of New York firefighters. A subset of this cohort experienced an accelerated rate of lung function decline over 15 years of post-September 11, 2001 (9/11) follow-up.

OBJECTIVES

To determine if early postexposure blood leukocyte concentrations are biomarkers for subsequent FEV1 decline and incident airflow limitation.

METHODS

Individual rates of forced expiratory volume in 1 second (FEV1) change were calculated for 9,434 firefighters using 88,709 spirometric measurements taken between September 11, 2001, and September 10, 2016. We categorized FEV1 change rates into three trajectories: accelerated FEV1 decline (FEV1 loss >64 ml/yr), expected FEV1 decline (FEV1 loss between 0 and 64 ml/yr), and improved FEV1 (positive rate of change >0 ml/yr). Occurrence of FEV1/FVC less than 0.70 after 9/11 defined incident airflow limitation. Using regression models, we assessed associations of post-9/11 blood eosinophil and neutrophil concentrations with subsequent FEV1 decline and airflow limitation, adjusted for age, race, smoking, height, WTC exposure level, weight change, and baseline lung function.

RESULTS

Accelerated FEV1 decline occurred in 12.7% of participants (1,199 of 9,434), whereas post-9/11 FEV1 improvement occurred in 8.3% (780 of 9,434). Higher blood eosinophil and neutrophil concentrations were each associated with accelerated FEV1 decline after adjustment for covariates (odds ratio [OR], 1.10 per 100 eosinophils/μl; 95% confidence interval [CI], 1.05-1.15; and OR, 1.10 per 1,000 neutrophils/μl; 95% CI, 1.05-1.15, respectively). Multivariable-adjusted linear regression models showed that a higher blood neutrophil concentration was associated with a faster rate of FEV1 decline (1.14 ml/yr decline per 1,000 neutrophils/μl; 95% CI, 0.69-1.60 ml/yr; P < 0.001). Higher blood eosinophil concentrations were associated with a faster rate of FEV1 decline in ever-smokers (1.46 ml/yr decline per 100 eosinophils/μl; 95% CI, 0.65-2.26 ml/yr; P < 0.001) but not in never-smokers (P for interaction = 0.004). Higher eosinophil concentrations were also associated with incident airflow limitation (adjusted hazard ratio, 1.10 per 100 eosinophils/μl; 95% CI, 1.04-1.15). Compared with the expected FEV1 decline group, individuals experiencing accelerated FEV1 decline were more likely to have incident airflow limitation (adjusted OR, 4.12; 95% CI, 3.30-5.14).

CONCLUSIONS

Higher post-9/11 blood neutrophil and eosinophil concentrations were associated with subsequent accelerated FEV1 decline in WTC-exposed firefighters. Both higher blood eosinophil concentrations and accelerated FEV1 decline were associated with incident airflow limitation in WTC-exposed firefighters.

Receptor for advanced glycation end-products and World Trade Center particulate induced lung function loss: A case-cohort study and murine model of acute particulate exposure

World Trade Center-particulate matter(WTC-PM) exposure and metabolic-risk are associated with WTC-Lung Injury(WTC-LI). The receptor for advanced glycation end-products (RAGE) is most highly expressed in the lung, mediates metabolic risk, and single-nucleotide polymorphisms at the AGER-locus predict forced expiratory volume(FEV). Our objectives were to test the hypotheses that RAGE is a biomarker of WTC-LI in the FDNY-cohort and that loss of RAGE in a murine model would protect against acute PM-induced lung disease. We know from previous work that early intense exposure at the time of the WTC collapse was most predictive of WTC-LI therefore we utilized a murine model of intense acute PM-exposure to determine if loss of RAGE is protective and to identify signaling/cytokine intermediates. This study builds on a continuing effort to identify serum biomarkers that predict the development of WTC-LI. A case-cohort design was used to analyze a focused cohort of male never-smokers with normal pre-9/11 lung function. Odds of developing WTC-LI increased by 1.2, 1.8 and 1.0 in firefighters with soluble RAGE (sRAGE)≥97pg/mL, CRP≥2.4mg/L, and MMP-9≤397ng/mL, respectively, assessed in a multivariate logistic regression model (ROCAUC of 0.72). Wild type(WT) and RAGE-deficient(Ager-/-) mice were exposed to PM or PBS-control by oropharyngeal aspiration. Lung function, airway hyperreactivity, bronchoalveolar lavage, histology, transcription factors and plasma/BAL cytokines were quantified. WT-PM mice had decreased FEV and compliance, and increased airway resistance and methacholine reactivity after 24-hours. Decreased IFN-γ and increased LPA were observed in WT-PM mice; similar findings have been reported for firefighters who eventually develop WTC-LI. In the murine model, lack of RAGE was protective from loss of lung function and airway hyperreactivity and was associated with modulation of MAP kinases. We conclude that in a multivariate adjusted model increased sRAGE is associated with WTC-LI. In our murine model, absence of RAGE mitigated acute deleterious effects of PM and may be a biologically plausible mediator of PM-related lung disease.

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.

An Official American Thoracic Society Workshop Report: Chemical Inhalational Disasters. Biology of Lung Injury, Development of Novel Therapeutics, and Medical Preparedness

This report is based on the proceedings from the Inhalational Lung Injury Workshop jointly sponsored by the American Thoracic Society (ATS) and the National Institutes of Health (NIH) Countermeasures Against Chemical Threats (CounterACT) program on May 21, 2013, in Philadelphia, Pennsylvania. The CounterACT program facilitates research leading to the development of new and improved medical countermeasures for chemical threat agents. The workshop was initiated by the Terrorism and Inhalational Disasters Section of the Environmental, Occupational, and Population Health Assembly of the ATS. Participants included both domestic and international experts in the field, as well as representatives from U.S. governmental funding agencies. The meeting objectives were to (1) provide a forum to review the evidence supporting current standard medical therapies, (2) present updates on our understanding of the epidemiology and underlying pathophysiology of inhalational lung injuries, (3) discuss innovative investigative approaches to further delineating mechanisms of lung injury and identifying new specific therapeutic targets, (4) present promising novel medical countermeasures, (5) facilitate collaborative research efforts, and (6) identify challenges and future directions in the ongoing development, manufacture, and distribution of effective and specific medical countermeasures. Specific inhalational toxins discussed included irritants/pulmonary toxicants (chlorine gas, bromine, and phosgene), vesicants (sulfur mustard), chemical asphyxiants (cyanide), particulates (World Trade Center dust), and respirable nerve agents.

Bronchial Reactivity and Lung Function After World Trade Center Exposure

BACKGROUND

World Trade Center (WTC)-exposed rescue/recovery workers endured massive respiratory insult from inhalation of particulate matter and gases, resulting in respiratory symptoms, loss of lung function, and, for many, bronchial hyperreactivity (BHR). The persistence of respiratory symptoms and lung function abnormalities has been well-documented, whereas persistence of BHR has not been investigated.

METHODS

A total of 173 WTC-exposed firefighters with bronchial reactivity measured within 2 years after September 11, 2001 (9/11) (baseline methacholine challenge test), were reevaluated in 2013 and 2014 (follow-up methacholine challenge test). FEV1 measurements were obtained from the late pre-9/11, early post-9/11, and late post-9/11 periods. Respiratory symptoms and corticosteroid treatment were recorded.

RESULTS

Bronchial reactivity remained stable (within 1 doubling dilution) for most (n = 101, 58%). Sixteen of 28 (57%) with BHR (provocative concentration of methacholine producing a 20% decline in FEV1 <8 mg/mL) at baseline had BHR at follow-up, and an additional 27 of the 145 (19%) without BHR at baseline had BHR at follow-up. In multivariable models, we found that BHR baseline was strongly associated with BHR follow-up (OR, 6.46) and that BHR at follow-up was associated with an estimated 15.4 mL/y greater FEV1 decline than experienced by those without BHR at follow-up. Annual FEV1 decline was moderated by corticosteroid use.

CONCLUSIONS

Persistent BHR and its deleterious influence on lung function suggest a role for airway inflammation in perpetuation of WTC-associated airway disease. In future massive occupational exposure to inorganic dust/gases, we recommend early and serial pulmonary function testing, including measurements of bronchial reactivity, when possible, and inhaled corticosteroid therapy for those with symptoms or pulmonary function tests consistent with airway disease.

Post-9/11/2001 lung function trajectories by sex and race in World Trade Center-exposed New York City emergency medical service workers

OBJECTIVE

To determine whether lung function trajectories after 9/11/2001 (9/11) differed by sex or race/ethnicity in World Trade Center-exposed Fire Department of the City of New York emergency medical service (EMS) workers.

METHOD

Serial cross-sectional study of pulmonary function tests (PFTs) taken between 9/11 and 9/10/2015. We used data from routine PFTs (forced expiratory volume in 1 s (FEV₁) and FEV₁% predicted), conducted at 12-18 month intervals. FEV₁ and FEV₁% predicted were assessed over time, stratified by sex, and race/ethnicity. We also assessed FEV₁ and FEV₁% predicted in current, former and never-smokers.

RESULTS

Among 1817 EMS workers, 334 (18.4%) were women, 979 (53.9%) self-identified as white and 939 (51.6%) were never-smokers. The median follow-up was 13.1 years (IQR 10.5-13.6), and the median number of PFTs per person was 11 (IQR 7-13). After large declines associated with 9/11, there was no discernible recovery in lung function. In analyses limited to never-smokers, the trajectory of decline in adjusted FEV₁ and FEV₁% predicted was relatively parallel for men and women in the 3 racial/ethnic groups. Similarly, small differences in FEV₁ annual decline between groups were not clinically meaningful. Analyses including ever-smokers were essentially the same.

CONCLUSIONS

14 years after 9/11, most EMS workers continued to demonstrate a lack of lung function recovery. The trajectories of lung function decline, however, were parallel by sex and by race/ethnicity. These findings support the use of routine, serial measures of lung function over time in first responders and demonstrate no sex or racial sensitivity to exposure-related lung function decline.

Biomarkers of patient intrinsic risk for upper and lower airway injury after exposure to the World Trade Center atrocity

BACKGROUND

High rates of upper and lower airways disease have occurred in Fire Department of the City of New York (FDNY) workers exposed to the World Trade Center (WTC) disaster site. Most experienced acute declines in pulmonary function, and some continued to experience decline over 14 years of follow-up. Similarly, some with rhinosinusitis had symptoms requiring sinus surgery.

AIM

To increase generalizability of biomarker investigation, we describe biomarkers of risk for upper and lower airway injury that do not require stored serum.

METHODS

We review WTC biomarker literature.

RESULTS

Cytokines expressed in stored serum from the first 6 months post-9/11 can identify individuals at higher risk for future abnormal pulmonary function.

CONCLUSION

This research will help identify individuals at high risk of lung and sinus disease that develop after these, or future, irritant exposures for intensive monitoring and treatment. It may also identify targets for effective therapeutic interventions. Am. J. Ind. Med. 59:788-794, 2016. © 2016 Wiley Periodicals, Inc.

FDNY and 9/11: Clinical services and health outcomes in World Trade Center-exposed firefighters and EMS workers from 2001 to 2016

BACKGROUND

After the World Trade Center (WTC) attacks on September 11, 2001, the Fire Department of the City of New York (FDNY) instituted a WTC medical monitoring and treatment program and established a data center to document health outcomes in the WTC-exposed workforce of ∼16,000 firefighters and EMS workers.

METHODS

FDNY schedules routine monitoring exams every 12-18 months and physical and mental health treatment appointments, as required.

RESULTS

FDNY research studies have consistently found that early arrival to work and/or prolonged work at the WTC-site increased the risks for adverse physical and mental health outcomes. To date, a substantial proportion has been diagnosed with obstructive airways disease, chronic rhinosinusitis, and gastroesophageal reflux disease; a quarter has two or more of these conditions.

CONCLUSIONS

While much has been learned, the entire spectrum and trajectory of WTC-related disorders and their mechanisms of onset and persistence remain to be fully described. Am. J. Ind. Med. 59:695-708, 2016. © 2016 Wiley Periodicals, Inc.