0
Original Research: Occupational and Environmental Lung Diseases |

Pulmonary Function Predicting Confirmed Recovery From Lower-Respiratory Symptoms in World Trade Center-Exposed Firefighters, 2001 to 2010Pulmonary Function and Symptom Recovery FREE TO VIEW

Jackie Soo, MPH; Mayris P. Webber, DrPH, MPH; Charles B. Hall, PhD; Hillel W. Cohen, DrPH, MPH; Theresa M. Schwartz, MS; Kerry J. Kelly, MD; David J. Prezant, MD, FCCP
Author and Funding Information

From the Department of Medicine (Mss Soo and Schwartz and Dr Prezant), Montefiore Medical Center, Bronx, NY; Department of Epidemiology and Population Health (Drs Webber, Hall, and Cohen), Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY; and Bureau of Health Services (Mss Soo and Schwartz and Drs Webber, Kelly, Prezant), Fire Department of the City of New York, Brooklyn, NY.

Correspondence to: Mayris P. Webber, DrPH, MPH, New York City Fire Department, Bureau of Health Services, 9 Metrotech Center, Brooklyn, NY 11201; e-mail: webberm@fdny.nyc.gov


Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.

Funding/Support: This work was supported by the National Institute for Occupational Safety and Health [RO1-OH07350].


Chest. 2012;142(5):1244-1250. doi:10.1378/chest.11-2210
Text Size: A A A
Published online

Background:  We examined the relationship between pulmonary function (FEV1) and confirmed recovery from three lower-respiratory symptoms (LRSs) (cough, dyspnea, and wheeze) up to 9 years after symptom onset.

Methods:  The study included white and black male World Trade Center (WTC)-exposed firefighters who reported at least one LRS on a medical monitoring examination during the first year after September 11, 2001. Confirmed recovery was defined as reporting no LRSs on two consecutive and all subsequent examinations. FEV1 was assessed at the first post-September 11, 2001, examination and at each examination where symptom information was ascertained. We used stratified Cox regression models to analyze FEV1, WTC exposure, and other variables in relation to confirmed symptom recovery.

Results:  A total of 4,368 firefighters met inclusion criteria and were symptomatic at year 1, of whom 1,592 (36.4%) experienced confirmed recovery. In univariable models, first post-September 11, 2001, concurrent, and difference between first post-September 11, 2001, and concurrent FEV1 values were all significantly associated with confirmed recovery. In adjusted analyses, both first post-September 11, 2001, FEV1 (hazard ratio [HR], 1.07 per 355-mL difference; 95% CI, 1.04-1.10) and FEV1 % predicted (HR, 1.08 per 10% predicted difference; 95% CI, 1.04-1.12) predicted confirmed recovery. WTC exposure had an inverse association with confirmed recovery in the model with FEV1, with the earliest arrival group less likely to recover than the latest arrival group (HR, 0.73; 95% CI, 0.58-0.92).

Conclusions:  Higher FEV1 and improvement in FEV1 after September 11, 2001, predicted confirmed LRS recovery, supporting a physiologic basis for recovery and highlighting consideration of spirometry as part of any postexposure respiratory health assessment.

Figures in this Article

After the September 11, 2001, terrorist attack on the World Trade Center (WTC), rescue workers from the Fire Department City of New York (FDNY) experienced substantial and immediate reductions in pulmonary function,1 particularly in FEV1. FDNY firefighters had an average adjusted FEV1 decline of 355 mL in the first 6 months after September 11, 2001, which is > 10 times the average annual age-related decline of 27 to 30 mL.2,3 Declines were persistent, resulting in little or no average recovery during the subsequent 6 years.3 During the same time, FDNY rescue workers reported increased upper-respiratory symptoms, lower-respiratory symptoms (LRSs), and gastroesophageal reflux symptoms,4 with an exposure-response gradient based on earliest arrival time5 and work duration.4,6

Modest associations between decreased pulmonary function and increased respiratory symptoms have been described in the general adult population7,8 and in elderly persons9; after occupational, dust, or pollutant exposures10; in tobacco smokers11,12; and in respiratory patients.1315 In WTC-exposed cohorts, we and others have shown significant associations between pulmonary function and respiratory symptoms.1,1619

Prior studies have focused on the incidence or prevalence of symptoms and declines in pulmonary function. To date, and to our knowledge, no longitudinal studies have examined whether FEV1 measured soon after WTC exposure predicts symptom resolution. We also are unaware of any such studies after other environmental or occupational exposures. Here, we report a longitudinal symptom study of the association of FEV1 with subsequent confirmed recovery from LRSs of cough, wheeze, or dyspnea over the 9-year period after September 11, 2001.

Within 1 month of September 11, 2001, the FDNY Bureau of Health Services instituted the formal Fire Department City of New York World Trade Center Medical Monitoring Program (FDNY-WTC-MMP) for all FDNY rescue and recovery workers. These monitoring visits were scheduled for every 12 to 18 months and included physical examinations, spirometry, and completion of self-administered health questionnaires. Study participation required written consent and was approved by the institutional review board at Montefiore Medical Center (protocol #07-09-320).

Study Population

The population comprised all white and black male active and retired FDNY firefighters hired before September 11, 2001, and who arrived at the WTC site within the first 2 weeks after September 11, 2001 (n = 10,092). Study subjects were also required to have had a monitoring examination during the first year after September 11, 2001 (n = 7,974) and to have reported at least one LRS during that examination (n = 5,442). To ensure sufficient follow-up, we further limited the analytic cohort to individuals who had at least three monitoring examinations from years 1 to 9 after September 11, 2001, as follows: one during year 1 and at least two thereafter, with the last one between years 7 and 9 (n = 4,368).

Spirometry

We assess pulmonary function at every medical monitoring examination by spirometry as previously described,3 with technique, quality assurance, and interpretation based on American Thoracic Society guidelines. EasyOne spirometers (ndd Medical Technologies) provide automated quality grading based on these guidelines.20 We eliminated from analysis spirometry measurements that had quality assurance grades of C or lower or that were done within 60 days of a prior spirometry. We calculated FEV1 % predicted using National Health and Nutrition Examination Survey equations,21 and limited the study population to white and black race because reliable prediction equations are not available for other races or ethnicities.

Symptoms

Symptom information was obtained from the self-administered health questionnaires, which were taken on the same day that spirometry was performed. We focused on the following three LRSs: cough, dyspnea, and wheeze. In the first year after September 11, 2001, symptom presence was determined by affirmative answers to the question, “Since the disaster, have you had any of the following new or worsening respiratory symptoms?” Multiple answers were allowed. In subsequent questionnaires, to determine the presence of current dyspnea or current wheeze, participants who indicated that they experienced either symptom were then asked whether their symptoms resolved or felt normal when on medication or treatment, improved, stayed the same, or worsened. Any response except resolved indicated current symptom presence. To determine the presence of current cough, we used a more stringent definition to approximate the clinical definition of cough. Participants were required to affirm a daily or almost daily cough when awake (apart from a cold) to be considered as having cough. We defined symptom recovery as reporting the absence of all LRSs on at least two consecutive surveys and reporting symptom absence on all subsequent surveys, including a final survey obtained in years 7 to 9 (confirmed recovery).

WTC Exposure

We used the FDNY-WTC-MMP Exposure Intensity Index to categorize exposure to the WTC site based on initial arrival time. Participants who arrived during the morning of September 11, 2001 (day 1) were categorized as arrival group 1, or the most exposed; those who arrived during the afternoon of September 11, 2001, were categorized as arrival group 2; those who arrived on day 2 were categorized as arrival group 3; and those who arrived any day between days 3 and 14 were categorized as arrival group 4, or the least exposed.4

Other Measures

The FDNY-WTC-MMP database includes date of birth, measured height, measured weight, self-reported race/ethnicity, smoking status, duty status (active or retired) and retirement date, and WTC exposure. Smoking status was self-reported as either current smoker, former smoker, or never smoker. Self-reported medication use was available from questionnaires beginning in August 2005 and for 100% of the analytic cohort. Individuals were asked, “Since 9/11/2001, have you received any of the following medications?” Those who reported using bronchodilators, inhaled corticosteroids, montelukast (Singulair; Merck & Co, Inc), or nebulized medications were considered to be using respiratory medication.

Data Analysis

We used the Cochran-Mantel-Haenzel test for trend for analysis of medication use by number of symptoms. To individually examine the relationship between demographic and other characteristics of the cohort in relation to confirmed recovery, we ran univariable Cox regression models. We also used Cox regression models to analyze FEV1 or FEV1 % predicted in relation to time to confirmed recovery in both univariable and multivariable analyses adjusted for demographic (age on September 11, 2001, and race) and other risk factors (WTC arrival group, smoking status, weight, and self-reported medication use). These analyses were performed separately for participants reporting a single symptom during year 1, two symptoms, and three symptoms. We then compared results from the three separate models to those from a single stratified Cox model that allowed each of the three groups a different baseline hazard function. Follow-up started on the date of a participant’s monitoring examination during year 1. Date of confirmed recovery was defined as the date of the first monitoring examination during follow-up in which an individual reported the absence of all symptoms. Participants without confirmed recovery were censored on the date of their last survey (up to year 9).

Both FEV1 and FEV1 % predicted were included in models as predictors of confirmed recovery in three different ways. First, we used an individual’s first FEV1 after September 11, 2001, and FEV1 % predicted taken during year 1. Second, we created a time-dependent, concurrent variable using the FEV1 and FEV1 % predicted values that were obtained on the same day that each symptom questionnaire was completed. Finally, we created a time-dependent difference variable with FEV1 only, using the difference between an individual’s concurrent FEV1 and his first FEV1 after September 11, 2001. This difference variable was calculated using only absolute and not FEV1 % predicted because the predictive equations take age into account, and thus, the time-to-event models would adjust for age twice with such a variable. Smoking status and weight at the time of each monitoring examination were analyzed as time-dependent variables to account for change over time.

We stratified the analytic cohort by quartile of their first FEV1 % predicted after September 11, 2001, and graphed the cumulative probability of confirmed persistent recovery over the 9-year follow-up period. All statistical analyses were performed using SAS version 9.2 (SAS Institute Inc), and S-Plus version 8.1 (TIBCO Software Inc) was used to graph the cumulative probability of confirmed recovery.

The analytic cohort included 4,368 WTC-exposed male firefighters who were symptomatic with at least one LRS during year 1 and had at least two follow-up visits as previously described, of whom 1,592 (36.4%) had confirmed recovery at some point during follow-up. At baseline, 1,856 (42.5%) had one LRS, 1,278 (29.3%) had two, and 1,234 (28.3%) had three, and mean ± SD FEV1 was 4.0 ± 0.7 L. The average number of visits with corresponding FEV1 measurements was four, with an average time between visits of about 2 years. The majority had FEV1 substantially above the lower limits of normal for the population. Table 1 shows time to confirmed recovery for specific characteristics of the analytic cohort.

Table Graphic Jump Location
Table 1 —Univariate Models of Time to Confirmed Recovery for Selected Demographic and Other Characteristics

Data are presented as No. (%) or mean ± SD. HR = hazard ratio.

a 

Age was modeled per 10 y.

Table 2 shows medications that individuals reported using between years 1 and 9 by the number of LRSs they reported during year 1. Steroids were the most commonly reported medication. There was a dose-response gradient between the number of symptoms reported and medication use. For example, the use of inhaled corticosteroids was reported by 33.5% reporting one symptom, 45.1% reporting two symptoms, and 54.5% reporting three symptoms (P < .001).

Table Graphic Jump Location
Table 2 —Medications That Participants Reported Ever Using

Data are presented as No. (%). All P < .001. LRS = lower-respiratory symptom.

A total of 1,592 of 4,368 participants (36.4%) demonstrated confirmed persistent recovery, which occurred a mean of 4.5 years after September 11, 2001. Of the 2,776 participants (63.6%) without confirmed persistent recovery, mean follow-up time was 8.1 years after September 11, 2001. Individuals with a lower FEV1 at baseline had a lower probability of recovery throughout the study period (Fig 1). Those in the first quartile (lowest baseline FEV1 % predicted) had the lowest cumulative probability of recovery (about 25%) at the end of follow-up. In contrast, those in the fourth quartile (highest baseline FEV1 % predicted) had the highest cumulative probability of recovery (about 45%) at the end of follow-up.

Figure Jump LinkFigure 1. Cumulative probability of confirmed recovery over the 9-year follow-up period by quartile of the first post-September 11, 2001, FEV1 % predicted (blue, > 103 [quartile 4]; green, 95-103 [quartile 3]; orange, 87-95 [quartile 2]; red, < 87 [quartile 1]).Grahic Jump Location

Table 3 shows separate univariable models predicting time to confirmed recovery using FEV1 and FEV1 % predicted. Hazard ratios (HRs) for FEV1 are estimated for every 355-mL increase because 355 mL was found to be the average decline in FEV1 for firefighters during the first 6 months after September 11, 2001.3 HRs for FEV1 % predicted were estimated for every 10-percentage point increase. Because the HRs obtained from three separate models were similar (model 1 included those having only one symptom during year 1, model 2 included those having only two symptoms during year 1, and model 3 included those having all three symptoms during year 1), we present results from the combined stratified Cox model. We also performed analyses in three separate cohorts defined by the particular LRS (cough, dyspnea, or wheeze) that individuals reported experiencing during year 1. Again, the magnitude of the associations between FEV1 and FEV1 % predicted and confirmed recovery were similar across all three symptom cohorts (results not shown); therefore, we used any LRS to denote symptom presence.

Table Graphic Jump Location
Table 3 —Univariable Models of Time to Confirmed Recovery With Three Different Measurements of FEV1 and FEV1 % Predicted

HRs for FEV1 measurements are per 355-mL increase. HRs for FEV1 % predicted measurements are per 10% increase. See Table 1 legend for expansion of abbreviation.

We found consistent positive associations between FEV1 and FEV1 % predicted and confirmed recovery. Concurrent measures showed the strongest association with confirmed recovery (HR, 1.15 for every 355-mL difference in FEV1; 95% CI, 1.12-1.18; HR, 1.17 for every 10% increase in FEV1 % predicted; 95% CI, 1.12-1.22). The first post-September 11, 2001, spirometry predicted confirmed recovery in univariable analysis, showing a slightly larger association with FEV1 % predicted (HR, 1.12 per 10% predicted difference; 95% CI, 1.08-1.17). The FEV1 difference variable also was associated with confirmed recovery because individuals who improved from their first FEV1 measurements after September 11, 2001, had a greater likelihood of recovery than those who did not improve (HR, 1.06 per 355-mL increase; 95% CI, 1.01-1.10).

First post-September 11, 2001, and concurrent FEV1 and FEV1 % predicted were also analyzed in separate multivariable models that controlled for risk factors described in Tables 4 and 5, respectively. In Table 4, even after adjusting for variables, including WTC arrival group, first post-September 11, 2001, FEV1 was predictive of confirmed recovery (HR, 1.07; 95% CI, 1.04-1.10). WTC exposure had a significant inverse association with confirmed recovery in that individuals in arrival group 1 (those who arrived during the morning of the collapse) were less likely to recover (HR, 0.73; 95% CI, 0.58-0.92) compared with those in arrival group 4. Age on September 11, 2001, and concurrent weight were also significantly associated with recovery. Older individuals were less likely to recover (HR, 0.82 for every 10 years; 95% CI, 0.77-0.89) as were those with higher weight (HR, 0.94 for every 10 lb; 95% CI, 0.93-0.96). Self-reported medication use was inversely associated with recovery (HR, 0.52; 95% CI, 0.47-0.57). The association of FEV1 remained for concurrent measures in multivariate analyses (HR, 1.14 for every 355-mL difference in FEV1; 95% CI, 1.10-1.18; HR, 1.11 for every 10% increase in FEV1 % predicted; 95% CI, 1.06-1.16) (data not shown).

Table Graphic Jump Location
Table 4 —Multivariable Models of Time to Confirmed Recovery With FEV1 and Other Risk Factors

See Table 1 legend for expansion of abbreviation.

a 

HRs are adjusted for all variables listed.

Table Graphic Jump Location
Table 5 —Multivariable Models of Time to Confirmed Recovery With FEV1 % Predicted and Other Risk Factors

See Table 1 legend for expansion of abbreviation.

a 

HRs are adjusted for all variables listed.

We found similar results with FEV1 % predicted in adjusted analyses. Age, height, and race were excluded from this model because these factors are already incorporated into the National Health and Nutrition Examination Survey prediction equations for FEV1. The first FEV1 % predicted (HR, 1.08; 95% CI, 1.04-1.12) after September 11, 2001, was associated with confirmed recovery; however, arrival group was now only marginally associated with confirmed recovery. Smoking status was significantly associated with recovery in that current smokers were less likely to experience confirmed recovery than never smokers (HR, 0.79; 95% CI, 0.65-0.96). In both models, we found that individuals who had ever reported the use of respiratory medications during follow-up were less likely to recover than those who never reported medication use (HR, 0.52; 95% CI, 0.47-0.57 in both models with FEV1 and FEV1 % predicted).

Using strict criteria to define confirmed recovery, 1,592 of 4,368 (36.4%) of initially symptomatic individuals recovered completely during follow-up. Higher FEV1 and FEV1 % predicted measured shortly after September 11, 2001, and an increase in FEV1 since immediately after September 11, 2001, were each found to predict confirmed LRS recovery up to 9 years post-September 11, 2001. Confirmed LRS recovery was least likely to occur in those arriving at the WTC on the morning of September 11, 2001, all of whom were caught in the dust cloud. Further, smoking status was also important because never smokers were more likely to recover than current or former smokers. This highlights the need for ongoing support of smoking cessation programs for WTC-exposed cohorts because smoking is a potentially modifiable impediment to recovery.

In WTC-exposed cohorts, previous studies have demonstrated associations between pulmonary function and LRS prevalence but have not investigated whether higher pulmonary function could predict resolution of LRS after exposure. In a recent study of non-FDNY WTC rescue and recovery workers, respiratory symptoms were associated with lower FEV1, lower FVC, and larger bronchodilator responses.19 A study of New York City Police Department emergency service responders found declines in FEV1 and FVC 6 years after September 11, 2001, which were associated with respiratory symptoms.18 A study of WTC-exposed area residents and area workers found significant associations between LRS and pulmonary function as determined by oscillometry.17 In WTC-exposed FDNY rescue workers, hyperreactivity on methacholine challenge testing 6 months after September 11, 2001, was also associated with LRS.16

Similar associations between FEV1 and LRS have been found after other noxious and chronic exposures, such as exposures in US coal miners22 and in tobacco smokers.11,12 Reduced pulmonary function has also been associated with numerous illnesses, such as diabetes,23 respiratory and cardiovascular disease,24 and all-cause mortality.25

To our knowledge, the current study is the first to longitudinally examine the association between FEV1 and confirmed LRS recovery. Similar studies have not been published in other WTC-exposed cohorts or after other noteworthy occupational and environmental exposures. We show that higher FEV1 values after September 11, 2001, can predict recovery from LRS up to 9 years later. It is important to acknowledge that the magnitude of this association, although statistically and clinically significant, was not large. Adding bronchodilator responsiveness or methacholine challenge hyperreactivity might improve this association, but these measures were not available for most of the cohort and would typically not be available during a mass screening program postdisaster.

It should be noted that 63.6% of the analytic cohort did not recover from LRS reported in the first year after September 11, 2001. This is a surprisingly high rate, considering the end of follow-up was 7 to 9 years after symptoms were first reported. This finding highlights the necessity of continued follow-up of the FDNY and other WTC-exposed rescue and recovery workers that focuses on treatment, tobacco cessation, and prevention of additional exposures not just by using respiratory protection but also, when possible, by removal from duties that might lead to hazardous exposures.

There are limitations to our study. First, although we stratified our analysis by the number of symptoms individuals reported immediately after September 11, 2001, we did not take into account a change in the number of respiratory symptoms experienced between year 1 and confirmed recovery. However, we did find that associations between FEV1 and individual symptoms, compared with the number of symptoms experienced, did not differ. That is, the magnitude of the HRs were similar for recovery from cough, recovery from dyspnea, and recovery from wheeze. Similarly, there was no difference between modeling any two symptom combinations or all three. In addition, confirmed recovery was no more likely if an individual experienced one, two, or three symptoms initially. A second limitation is that time to recovery may be inflated because some individuals may not have come in for monitoring examinations at regular intervals, and thus, their recovery would have been recorded only at the first time they completed a questionnaire. However, we do not believe that this was a serious problem because the mean number of follow-up visits does not differ by quartile ranking of FEV1 at the first post-September 11, 2001 visit: The mean number of follow-up visits ranged from 3.9 to 4.2 in the four quartile groups. Finally, we could not clearly establish the role of treatment in confirmed recovery because we found that individuals who reported using respiratory medications were less likely to recover. We believe that this result suggests that medication use serves as a surrogate for symptom severity rather than as an indicator of treatment compliance or success in the population. In support of this, we also found that those with more symptoms were more likely to report taking medications, especially inhaled corticosteroids, which is consistent with National Heart, Lung, and Blood Institute guidelines. Understanding this complex relationship would require analysis of medication adherence records, which were not available.

In conclusion, higher FEV1 was predictive of confirmed persistent LRS recovery. Given the ability to predict symptom resolution, spirometric measurements should be considered for inclusion as a regular part of any postexposure respiratory health assessment because both absolute and FEV1 % predicted values can be important prognostic factors of recovery and can focus treatment on those most at risk.

Author contributions: Dr Prezant had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Ms Soo: contributed to the data analysis, preparation of the first draft of the manuscript, and review and final approval of the manuscript.

Dr Webber: contributed to the study design, data analysis, project management, and review and final approval of the manuscript.

Dr Hall: contributed analytic and statistical guidance and to the review and final approval of the manuscript.

Dr Cohen: contributed to the review and final approval of the manuscript.

Ms Schwartz: contributed analytic and statistical guidance and to the review and final approval of the manuscript.

Dr Kelly: contributed to the study design, data analysis, project management, and review and final approval of the manuscript.

Dr Prezant: contributed to the study design, data analysis, project management, and review and final approval of the manuscript.

Financial/nonfinancial disclosures: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Role of sponsor: The sponsor had no role in the design of the study, the collection and analysis of the data, or in the preparation of the manuscript.

FDNY

Fire Department City of New York

FDNY-WTC-MMP

Fire Department City of New York World Trade Center Medical Monitoring Program

HR

hazard ratio

LRS

lower-respiratory symptom

WTC

World Trade Center

Banauch GI, Hall C, Weiden M, et al. Pulmonary function after exposure to the World Trade Center collapse in the New York City Fire Department. Am J Respir Crit Care Med. 2006;174(3):312-319. [CrossRef] [PubMed]
 
Musk AW, Peters JM, Wegman DH. Lung function in fire fighters, I: a three year follow-up of active subjects. Am J Public Health. 1977;67(7):626-629. [CrossRef] [PubMed]
 
Aldrich TK, Gustave J, Hall CB, et al. Lung function in rescue workers at the World Trade Center after 7 years. N Engl J Med. 2010;362(14):1263-1272. [CrossRef] [PubMed]
 
Webber MP, Gustave J, Lee R, et al. Trends in respiratory symptoms of firefighters exposed to the World Trade Center disaster: 2001-2005. Environ Health Perspect. 2009;117(6):975-980. [CrossRef] [PubMed]
 
Prezant DJ, Weiden M, Banauch GI, et al. Cough and bronchial responsiveness in firefighters at the World Trade Center site. N Engl J Med. 2002;347(11):806-815. [CrossRef] [PubMed]
 
Feldman DM, Baron SL, Bernard BP, et al. Symptoms, respirator use, and pulmonary function changes among New York City firefighters responding to the World Trade Center disaster. Chest. 2004;125(4):1256-1264. [CrossRef] [PubMed]
 
Burney PG, Laitinen LA, Perdrizet S, et al. Validity and repeatability of the IUATLD (1984) Bronchial Symptoms Questionnaire: an international comparison. Eur Respir J. 1989;2(10):940-945. [PubMed]
 
Sunyer J, Basagaña X, Roca J, et al;; ECRHS study ECRHS study. Relations between respiratory symptoms and spirometric values in young adults: the European community respiratory health study. Respir Med. 2004;98(10):1025-1033. [CrossRef] [PubMed]
 
Sherrill DL, Lebowitz MD, Knudson RJ, Burrows B. Longitudinal methods for describing the relationship between pulmonary function, respiratory symptoms and smoking in elderly subjects: the Tucson Study. Eur Respir J. 1993;6(3):342-348. [PubMed]
 
Nuvolone D, Della Maggiore R, Maio S, et al. Geographical information system and environmental epidemiology: a cross-sectional spatial analysis of the effects of traffic-related air pollution on population respiratory health. Environ Health. 2011;10:12. [CrossRef] [PubMed]
 
Kanner RE, Connett JE, Williams DE, Buist AS. Effects of randomized assignment to a smoking cessation intervention and changes in smoking habits on respiratory symptoms in smokers with early chronic obstructive pulmonary disease: the Lung Health Study. Am J Med. 1999;106(4):410-416. [CrossRef] [PubMed]
 
Kanner RE, Anthonisen NR, Connett JE; Lung Health Study Research Group Lung Health Study Research Group. Lower respiratory illnesses promote FEV(1) decline in current smokers but not ex-smokers with mild chronic obstructive pulmonary disease: results from the lung health study. Am J Respir Crit Care Med. 2001;164(3):358-364. [PubMed]
 
Donaldson GC, Seemungal TA, Bhowmik A, Wedzicha JA. Relationship between exacerbation frequency and lung function decline in chronic obstructive pulmonary disease. Thorax. 2002;57(10):847-852. [CrossRef] [PubMed]
 
Donaldson GC, Seemungal TA, Patel IS, et al. Airway and systemic inflammation and decline in lung function in patients with COPD. Chest. 2005;128(4):1995-2004. [CrossRef] [PubMed]
 
Wilkinson TM, Donaldson GC, Johnston SL, Openshaw PJ, Wedzicha JA. Respiratory syncytial virus, airway inflammation, and FEV1 decline in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2006;173(8):871-876. [CrossRef] [PubMed]
 
Banauch GI, Alleyne D, Sanchez R, et al. Persistent hyperreactivity and reactive airway dysfunction in firefighters at the World Trade Center. Am J Respir Crit Care Med. 2003;168(1):54-62. [CrossRef] [PubMed]
 
Friedman SM, Maslow CB, Reibman J, et al. Case-control study of lung function in World Trade Center Health Registry area residents and workers. Am J Respir Crit Care Med. 2011;184(5):582-589. [CrossRef] [PubMed]
 
Kleinman EJ, Cucco RA, Martinez C, et al. Pulmonary function in a cohort of New York City Police Department emergency responders since the 2001 World Trade Center disaster. J Occup Environ Med. 2011;53(6):618-626. [CrossRef] [PubMed]
 
Udasin I, Schechter C, Crowley L, et al. Respiratory symptoms were associated with lower spirometry results during the first examination of WTC responders. J Occup Environ Med. 2011;53(1):49-54. [CrossRef] [PubMed]
 
Miller MR, Hankinson J, Brusasco V, et al;; ATS/ERS Task Force ATS/ERS Task Force. Standardisation of spirometry. Eur Respir J. 2005;26(2):319-338. [CrossRef] [PubMed]
 
Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a sample of the general U.S. population. Am J Respir Crit Care Med. 1999;159(1):179-187. [PubMed]
 
Beeckman LA, Wang ML, Petsonk EL, Wagner GR. Rapid declines in FEV1 and subsequent respiratory symptoms, illnesses, and mortality in coal miners in the United States. Am J Respir Crit Care Med. 2001;163(3 pt 1):633-639. [PubMed]
 
Davis TM, Knuiman M, Kendall P, Vu H, Davis WA. Reduced pulmonary function and its associations in type 2 diabetes: the Fremantle Diabetes Study. Diabetes Res Clin Pract. 2000;50(2):153-159. [CrossRef] [PubMed]
 
Ebi-Kryston KL. Respiratory symptoms and pulmonary function as predictors of 10-year mortality from respiratory disease, cardiovascular disease, and all causes in the Whitehall Study. J Clin Epidemiol. 1988;41(3):251-260. [CrossRef] [PubMed]
 
Schünemann HJ, Dorn J, Grant BJ, Winkelstein W Jr, Trevisan M. Pulmonary function is a long-term predictor of mortality in the general population: 29-year follow-up of the Buffalo Health Study. Chest. 2000;118(3):656-664. [CrossRef] [PubMed]
 

Figures

Figure Jump LinkFigure 1. Cumulative probability of confirmed recovery over the 9-year follow-up period by quartile of the first post-September 11, 2001, FEV1 % predicted (blue, > 103 [quartile 4]; green, 95-103 [quartile 3]; orange, 87-95 [quartile 2]; red, < 87 [quartile 1]).Grahic Jump Location

Tables

Table Graphic Jump Location
Table 1 —Univariate Models of Time to Confirmed Recovery for Selected Demographic and Other Characteristics

Data are presented as No. (%) or mean ± SD. HR = hazard ratio.

a 

Age was modeled per 10 y.

Table Graphic Jump Location
Table 2 —Medications That Participants Reported Ever Using

Data are presented as No. (%). All P < .001. LRS = lower-respiratory symptom.

Table Graphic Jump Location
Table 3 —Univariable Models of Time to Confirmed Recovery With Three Different Measurements of FEV1 and FEV1 % Predicted

HRs for FEV1 measurements are per 355-mL increase. HRs for FEV1 % predicted measurements are per 10% increase. See Table 1 legend for expansion of abbreviation.

Table Graphic Jump Location
Table 4 —Multivariable Models of Time to Confirmed Recovery With FEV1 and Other Risk Factors

See Table 1 legend for expansion of abbreviation.

a 

HRs are adjusted for all variables listed.

Table Graphic Jump Location
Table 5 —Multivariable Models of Time to Confirmed Recovery With FEV1 % Predicted and Other Risk Factors

See Table 1 legend for expansion of abbreviation.

a 

HRs are adjusted for all variables listed.

References

Banauch GI, Hall C, Weiden M, et al. Pulmonary function after exposure to the World Trade Center collapse in the New York City Fire Department. Am J Respir Crit Care Med. 2006;174(3):312-319. [CrossRef] [PubMed]
 
Musk AW, Peters JM, Wegman DH. Lung function in fire fighters, I: a three year follow-up of active subjects. Am J Public Health. 1977;67(7):626-629. [CrossRef] [PubMed]
 
Aldrich TK, Gustave J, Hall CB, et al. Lung function in rescue workers at the World Trade Center after 7 years. N Engl J Med. 2010;362(14):1263-1272. [CrossRef] [PubMed]
 
Webber MP, Gustave J, Lee R, et al. Trends in respiratory symptoms of firefighters exposed to the World Trade Center disaster: 2001-2005. Environ Health Perspect. 2009;117(6):975-980. [CrossRef] [PubMed]
 
Prezant DJ, Weiden M, Banauch GI, et al. Cough and bronchial responsiveness in firefighters at the World Trade Center site. N Engl J Med. 2002;347(11):806-815. [CrossRef] [PubMed]
 
Feldman DM, Baron SL, Bernard BP, et al. Symptoms, respirator use, and pulmonary function changes among New York City firefighters responding to the World Trade Center disaster. Chest. 2004;125(4):1256-1264. [CrossRef] [PubMed]
 
Burney PG, Laitinen LA, Perdrizet S, et al. Validity and repeatability of the IUATLD (1984) Bronchial Symptoms Questionnaire: an international comparison. Eur Respir J. 1989;2(10):940-945. [PubMed]
 
Sunyer J, Basagaña X, Roca J, et al;; ECRHS study ECRHS study. Relations between respiratory symptoms and spirometric values in young adults: the European community respiratory health study. Respir Med. 2004;98(10):1025-1033. [CrossRef] [PubMed]
 
Sherrill DL, Lebowitz MD, Knudson RJ, Burrows B. Longitudinal methods for describing the relationship between pulmonary function, respiratory symptoms and smoking in elderly subjects: the Tucson Study. Eur Respir J. 1993;6(3):342-348. [PubMed]
 
Nuvolone D, Della Maggiore R, Maio S, et al. Geographical information system and environmental epidemiology: a cross-sectional spatial analysis of the effects of traffic-related air pollution on population respiratory health. Environ Health. 2011;10:12. [CrossRef] [PubMed]
 
Kanner RE, Connett JE, Williams DE, Buist AS. Effects of randomized assignment to a smoking cessation intervention and changes in smoking habits on respiratory symptoms in smokers with early chronic obstructive pulmonary disease: the Lung Health Study. Am J Med. 1999;106(4):410-416. [CrossRef] [PubMed]
 
Kanner RE, Anthonisen NR, Connett JE; Lung Health Study Research Group Lung Health Study Research Group. Lower respiratory illnesses promote FEV(1) decline in current smokers but not ex-smokers with mild chronic obstructive pulmonary disease: results from the lung health study. Am J Respir Crit Care Med. 2001;164(3):358-364. [PubMed]
 
Donaldson GC, Seemungal TA, Bhowmik A, Wedzicha JA. Relationship between exacerbation frequency and lung function decline in chronic obstructive pulmonary disease. Thorax. 2002;57(10):847-852. [CrossRef] [PubMed]
 
Donaldson GC, Seemungal TA, Patel IS, et al. Airway and systemic inflammation and decline in lung function in patients with COPD. Chest. 2005;128(4):1995-2004. [CrossRef] [PubMed]
 
Wilkinson TM, Donaldson GC, Johnston SL, Openshaw PJ, Wedzicha JA. Respiratory syncytial virus, airway inflammation, and FEV1 decline in patients with chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2006;173(8):871-876. [CrossRef] [PubMed]
 
Banauch GI, Alleyne D, Sanchez R, et al. Persistent hyperreactivity and reactive airway dysfunction in firefighters at the World Trade Center. Am J Respir Crit Care Med. 2003;168(1):54-62. [CrossRef] [PubMed]
 
Friedman SM, Maslow CB, Reibman J, et al. Case-control study of lung function in World Trade Center Health Registry area residents and workers. Am J Respir Crit Care Med. 2011;184(5):582-589. [CrossRef] [PubMed]
 
Kleinman EJ, Cucco RA, Martinez C, et al. Pulmonary function in a cohort of New York City Police Department emergency responders since the 2001 World Trade Center disaster. J Occup Environ Med. 2011;53(6):618-626. [CrossRef] [PubMed]
 
Udasin I, Schechter C, Crowley L, et al. Respiratory symptoms were associated with lower spirometry results during the first examination of WTC responders. J Occup Environ Med. 2011;53(1):49-54. [CrossRef] [PubMed]
 
Miller MR, Hankinson J, Brusasco V, et al;; ATS/ERS Task Force ATS/ERS Task Force. Standardisation of spirometry. Eur Respir J. 2005;26(2):319-338. [CrossRef] [PubMed]
 
Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a sample of the general U.S. population. Am J Respir Crit Care Med. 1999;159(1):179-187. [PubMed]
 
Beeckman LA, Wang ML, Petsonk EL, Wagner GR. Rapid declines in FEV1 and subsequent respiratory symptoms, illnesses, and mortality in coal miners in the United States. Am J Respir Crit Care Med. 2001;163(3 pt 1):633-639. [PubMed]
 
Davis TM, Knuiman M, Kendall P, Vu H, Davis WA. Reduced pulmonary function and its associations in type 2 diabetes: the Fremantle Diabetes Study. Diabetes Res Clin Pract. 2000;50(2):153-159. [CrossRef] [PubMed]
 
Ebi-Kryston KL. Respiratory symptoms and pulmonary function as predictors of 10-year mortality from respiratory disease, cardiovascular disease, and all causes in the Whitehall Study. J Clin Epidemiol. 1988;41(3):251-260. [CrossRef] [PubMed]
 
Schünemann HJ, Dorn J, Grant BJ, Winkelstein W Jr, Trevisan M. Pulmonary function is a long-term predictor of mortality in the general population: 29-year follow-up of the Buffalo Health Study. Chest. 2000;118(3):656-664. [CrossRef] [PubMed]
 
NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

CHEST Journal Articles
CHEST Collections
PubMed Articles
Guidelines
  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543