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RATIONALE: The long-term outcomes of acute irritant-induced asthma (IIA) are mostly unknown. OBJECTIVES: To study the long-term outcomes of IIA. METHODS: We reassessed 35 subjects who experienced IIA at a mean interval of 13.6 +/- 5.2 years. MEASUREMENTS AND MAIN RESULTS: The causal agent was chlorine in 20 cases (57%). At diagnosis, the mean +/- SD FEV(1) was 74.5 +/- 19.5% predicted, and all subjects showed bronchial hyperresponsiveness. At reassessment, all subjects reported respiratory symptoms, and 24 (68%) were on inhaled steroids. There were no significant improvements in FEV(1) and FEV(1)/FVC values. Twenty-three subjects had a methacholine test, and only six subjects had normal levels of responsiveness. Of the remaining 12 subjects, six had improvement in FEV(1) after bronchodilator >or=10%. In samples of induced sputum obtained from 27 subjects, six had eosinophils >or=2%. Levels of inflammatory and remodeling mediators were higher than in control subjects but were no different from subjects with occupational asthma due to sensitization. Quality of life score was 4.4 +/- 1.5 on a 0 (worst) to 7 (best) scale. Twelve subjects had an abnormal depression score. CONCLUSIONS: This study provides the first evidence of significant long-term impact of acute IIA on various outcomes. [ABSTRACT FROM AUTHOR]

Background/aim: This study used information from the questionnaire alone or in conjunction with clinical tests, such as skin-prick testing (SPT) and bronchial responsiveness (BR) testing at entry, to develop models for estimating the probability of the occurrence of specific lgE-sensitisation to and respiratory symptoms in contact with laboratory animal (LA) allergens after 32 months' training in an animal health technology programme. Methods: Four multivariable logistic regression models were developed for each endpoint, consisting of (1) questionnaire; (2) questionnaire and SPT; (3) questionnaire and BR testing; and (4) questionnaire, SPT and BR testing. The prognostic models were derived from a cohort of Canadian animal health technology apprentices. The models' internal validity and diagnostic accuracy were evaluated and compared. Results: Symptoms indicative of asthma and allergic symptoms at baseline composed the final questionnaire model for the occurrence of occupational sensitisation and symptoms. Both questionnaire models showed a good discrimination (area under the receiver operating characteristics curve were 0.73 and 0.78, respectively) and calibration (Hosmer-Lemeshow test p value >0.10). Addition of SPT and/or BR testing increased the specificity of the questionnaire model for LA sensitisation, but not for symptoms at work. To facilitate their application in practice, the final questionnaire models were converted to easy-to-use scoring system. Conclusions: Questionnaire is an easy tool that can give accurate prediction of the incidence of occupational sensitisation and symptoms. [ABSTRACT FROM AUTHOR]

Background: Serial peak expiratory flow rate (PEF) recording has been advocated as a sensitive and specific means of confirming work related asthma. The optimum number of recordings per day to achieve the best between-reader and within-reader reproducibility and sensitivity/specificity ratio compared with the final diagnosis determined by specific inhalation challenges is unknown.Methods: PEF recording was carried out every two hours in 74 subjects referred for possible occupational asthma. Specific inhalation challenges performed in a hospital laboratory or at the workplace (positive in 33 subjects and negative in 41) were considered the gold standard. The duration of monitoring at work and away from work was at least two weeks each. Graphs of PEF recordings were generated in four different ways: every two hours, four times/day, three times/day, and every morning and evening. The graphs were assessed by three readers in three different centres in a blind manner. Furthermore, one third of each type of graph was read blind by the same reader one week after the initial interpretation.Results: Agreement between the three readers was a little more frequent (82%) in the case of the every two hour readings than for the other types of readings (70% v 77%). Agreement between at least two of the three readers occurred in 73% of positive challenges (sensitivity) and in 78% of negative challenges (specificity) for every two hour readings. The figures varied from 61% to 70% for positive challenges and from 78% to 88% for negative challenges for the other types of readings. Within-subject reproducibility from one reading to the next (one week apart) was excellent (83% to 100%).Conclusions: Recording PEF every two hours results in a slightly more satisfactory agreement between readers and in concordance in terms of sensitivity/specificity than less frequent PEF readings, although the four times a day assessment is almost as satisfactory. [ABSTRACT FROM AUTHOR]

Objective: The aim was to determine the prevalence of persistent respiratory symptoms and bronchial hyper-responsiveness due to reactive airways dysfunction syndrome in a population of construction workers at moderate to high risk of developing the syndrome, at an interval of 18 to 24 months after multiple exposures to chlorine gas during renovations to a pulp and paper mill.Design and Participants: 71 of 289 exposed workers (25%) were identified on the basis of an exposure and the onset of respiratory symptoms shortly after this event (moderate to high risk). A standardised respiratory questionnaire was first presented, followed by spirometry and a methacholine inhalation test on those whose questionnaire suggested the persistence of respiratory symptoms.Results: 64 of 71 (90%) subjects completed the respiratory questionnaire at the time of the follow up. The questionnaire suggested a persistence of respiratory symptoms in 58 of the 64 workers (91%). Of the 58 subjects, 51 underwent spirometry and assessment of bronchial responsiveness. All of them used bronchodilators as required (not regularly) and four required inhaled anti-inflammatory preparations. Sixteen had bronchial obstruction (forced expiratory volume in one second) (FEV1 < 80% predicted) and 29 showed significant bronchial hyper-responsiveness.Conclusion: Of the subjects (n = 71) who were at moderate to high risk of developing reactive airways dysfunction syndrome after being exposed to chlorine and were seen 18 to 24 months after exposure ended, 58 (82%) still had respiratory symptoms, 16 (23%) had evidence of bronchial obstruction, and 29 (41%) had bronchial hyper-responsiveness. [ABSTRACT FROM AUTHOR]

Abstract Background The Juniper Asthma Specific Quality of Life Questionnaire (AQLQ(S)) is a questionnaire that allows measurement of disease specific quality of life. We wanted to examine correlations between the (AQLQ(S)) general and different subscale scores and both psychiatric morbidity and levels of psychological distress in individuals with occupational asthma (OA) and to determine if results in the emotional function subscale allow identification of individuals with clinically significant psychological distress or current psychiatric disorders. Methods This was a cross-sectional study of individuals with OA who were assessed during a re-evaluation for permanent disability, after they were no longer exposed to the sensitizing agent. Patients underwent a general sociodemographic and medical history evaluation, a brief psychiatric interview (Primary Care Evaluation of Mental Disorders, PRIME-MD) and completed a battery of questionnaires including the AQLQ(S), the St-Georges Respiratory Questionnaire (SGRQ), and the Psychiatric Symptom Index (PSI). Results There was good internal consistency (Cronbach alpha = 0.936 for the AQLQ(S) total score) and construct validity for the AQLQ(S) (Spearman rho = -0.693 for the SGRQ symptom score and rho = -0.650 for the asthma severity score). There were medium to large correlations between the total score of the AQLQ(S) and the SGRQ symptom score (r = -.693), and PSI total (r = -.619) and subscale scores (including depression, r = -.419; anxiety, r = -.664; anger, r = -.367; cognitive disturbances, r = -.419). A cut-off of 5.1 on the AQLQ(S) emotional function subscale (where 0 = high impairment and 7 = no impairment) had the best discriminative value to distinguish individuals with or without clinically significant psychiatric distress according to the PSI, and a cut-off of 4.7 best distinguished individuals with or without a current psychiatric disorder according to the PRIME-MD. Conclusions Impaired quality of life is associated with psychological distress and psychiatric disorders in individuals with OA. Findings suggest that the AQLQ(S) questionnaire may be used to identify patients with potentially clinically significant levels of psychological distress.

Background: The diagnosis of occupational asthma (OA) can be challenging and needs a stepwise approach. However, the predictive value of the methacholine challenge has never been addressed specifically in this context., Objective: We sought to evaluate the sensitivity, specificity, and positive and negative predictive values of the methacholine challenge in OA., Methods: A Canadian database was used to review 1012 cases of workers referred for a suspicion of OA between 1983 and 2011 and having had a specific inhalation challenge. We calculated the sensitivity, specificity, and positive and negative predictive values of methacholine challenges at baseline of the specific inhalation challenge, at the workplace, and outside work., Results: At baseline, the methacholine challenge showed an overall sensitivity of 80.2% and a specificity of 47.1%, with positive and negative predictive values of 36.5% and 86.3%, respectively. Among the 430 subjects who were still working, the baseline measures displayed a sensitivity of 95.4%, a specificity of 40.1%, and positive and negative predictive values of 41.1% and 95.2%, respectively. Among the 582 subjects tested outside work, the baseline measures demonstrated a sensitivity and specificity of 66.7% and 52%, respectively, and positive and negative predictive values of 31.9% and 82.2%, respectively. When considering all subjects tested by a methacholine challenge at least once while at work (479), the sensitivity, specificity, and positive and negative predictive values were 98.1%, 39.1%, and 44.0% and 97.7%, respectively., Conclusion: A negative methacholine challenge in a patient still exposed to the causative agent at work makes the diagnosis of OA very unlikely., (Copyright © 2015 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Objective: To compare the long-term status of workers with occupational asthma (OA) with those of subjects with work-exacerbated asthma (WEA) and nonasthmatic (NA) workers., Methods: We contacted 179 subjects investigated for suspected OA at Hôpital du Sacré-Coeur de Montréal, Montreal, Quebec, Canada, from 1997 to 2007. Participants completed questionnaires on psychological and functional status, followed by a telephone interview about socioprofessional outcomes and health care utilization., Results: The OA workers are more likely to have been removed from the workplace than the WEA workers. The health-related quality of life of all workers was still impaired. A high prevalence of psychiatric disorders was found among OA and WEA workers. Compared with WEA and OA workers, the NA group showed a higher rate of physician consultations for all causes., Conclusions: Regardless of the diagnosis they received, these workers need to benefit from psychosocial support in the period after investigation for suspicion of OA.

Objective: To examine the association between clinical and socioeconomic variables and their influence on psychological and cost outcomes in patients with occupational asthma (OA)., Methods: Longitudinal study of 60 subjects who claimed compensation for OA in Quebec. Besides clinical markers of asthma, quality of life (QOL), psychological distress (PD) measures, and an instrument to diagnose mental disorders were used., Results: The QOL and PD parameters had moderate correlations with clinical markers of OA. Asthma severity, employment, marital status, income, and the length of employment with the employer showed the strongest associations with QOL and PD. More-impaired QOL was associated with higher direct costs for compensation., Conclusion: Impaired QOL and PD are frequent among subjects with OA receiving compensation and are associated with clinical markers of OA and socioeconomic factors.

Background: In a previous study, the authors assessed direct costs for occupational asthma (OA) in a random sample of eight to 10 accepted claims per year for OA between 1988 and 2002. Compensation for loss of income (CLI) was found to be significantly higher for men and for OA caused by low-molecular-weight agents., Objectives and Methods: To identify sociodemographic factors that modulate CLI, the dossier of each claimant in the previous study was re-examined., Results: Higher CLI costs were directly related to the duration of CLI (over which loss of income was reimbursed) (r=0.65). Costs of CLI were higher in patients 30 years of age or older at diagnosis, married subjects and individuals who were offered early retirement or were enrolled in an active interventional rehabilitation program. Higher CLI costs in men, but not in women, were associated with the following sociodemographic factors: older age, different rehabilitation program (early retirement and active program versus no specific program) and married status. Older age was found to be significant in the multivariate analysis performed for men. The cost of CLI was higher in workers with OA caused by low-molecular-weight agents. Although proportionally fewer men and younger workers were affected with OA caused by low-molecular-weight agents, the longer duration of CLI for this category of agent could explain the higher costs., Conclusion: Higher costs for CLI were associated in men (but not women) with older age, married status and type of rehabilitation program (early retirement and active rehabilitation). Higher costs of CLI for OA caused by low-molecular-weight agents were associated with a longer duration of CLI per se, and not with sociodemographic factors.

The most important factor for the prognosis of occupational asthma is the length of exposure with symptoms prior to removal from exposure. We wanted to identify factors, including socioeconomic status, that can influence the delay in submitting a claim to a medicolegal agency after the onset of asthmatic symptoms, and to confirm that this delay is associated with worse respiratory prognosis and higher direct costs. This is a cross-sectional study of subjects who claimed compensation for occupational asthma at the Workers' Compensation Board of Quebec, Canada. Data were collected at re-evaluation ∼2.5 yrs after diagnosis. Information on the number of years with symptoms and removal from exposure was obtained from the medicolegal file. 60 subjects were included in the study. Being older, having a revenue of >30,000 Canadian dollars and having occupational asthma due to high molecular weight agents were all positively associated with the number of years of exposure with symptoms before removal from exposure. Subjects with persistent airway hyperresponsiveness at follow-up had a higher number of years with symptoms. Experiencing symptoms in the workplace for <1 yr generated lower direct costs. These findings might help in surveillance programmes that could be preferentially targeted for these subgroups of workers.

Background: The interpretation of methacholine test results do not usually consider the symptoms for which the subject was referred and those that occur during the test., Objective: To assess the association between methacholine test results and symptoms, and to examine variables that may affect this association.&nbsp;METHODS A total of 400 prospectively chosen subjects who underwent methacholine testing for possible asthma were investigated. The subjects answered a short questionnaire regarding the symptoms for which they had been referred and those that were encountered during the methacholine test., Results: The positive predictive value for the reproduction of symptoms during the test compared with symptoms for which subjects had been referred were 84% for dyspnea, 87% for cough, 81% for wheezing and 72% for chest tightness. The positive predictive value among the values obtained by measuring the provocative concentration of methacholine causing a 20% fall (PC20) in forced expiratory volume in 1 s on the one hand, and specific symptoms on the other, varied by up to approximately 50%; negative predictive values were higher. Forty-eight per cent of subjects with a PC20 of 16 mg⁄mL or lower reported that the test had globally reproduced their symptoms. This association was significantly stronger in women, young subjects and those taking inhaled steroids., Conclusions: The methacholine test generally reproduced the symptoms for which the subjects were referred. The absence of a specific symptom (eg, dyspnea, cough, wheezing or chest tightness), either in daily life or at the time of methacholine testing, was more generally associated with a negative test than the reverse. The global impression that the test had reproduced what the patient had experienced in daily life was significantly associated with a positive test (ie, a PC20 of 16 mg⁄mL or lower), with the association being stronger in young subjects and women.

Background: Acute irritant-induced asthma (IrIa) or reactive airways dysfunction syndrome is caused by exposure to a high concentration of an agent. The long-term pathologic consequences of IrIa remain thus far unknown., Objective: The aim of our study was to investigate the chronic airway inflammation and remodeling that occur in association with IrIa., Methods: Ten subjects with a history of IrIa (mean interval of 10.9 years, minimum of 4 years, since the inhalational accident) underwent bronchoscopy followed by bronchoalveolar lavage and bronchial biopsies. Immunologic and morphologic data from patients with IrIa were compared with those of patients with mild to moderate asthma as well as healthy controls., Results: Bronchoalveolar lavage fluid analysis showed increased eosinophil and neutrophil counts in 30% and 60% of subjects with IrIa, respectively. In the supernatant of bronchoalveolar lavage, we found a significant increase in the majority of mediators compared with healthy subjects and a significant increase in eosinophilic cationic protein, IL-8, basic fibroblast growth factor, and matrix metalloproteinase 1 compared with control patients with asthma. Evaluation of basement membrane thickness (subepithelial fibrosis) demonstrated a significant increase in patients with IrIa compared with healthy subjects and subjects with asthma. Basement membrane thickness also significantly correlated with the PC(20) value. The epithelial cell detachment showed an elevated although not significant trend compared with subjects with asthma and control subjects. Immunocytochemical analysis demonstrated increases in the number of eosinophil cationic protein and TGF-beta1-positive cells compared with healthy controls., Conclusion: This study provides evidence of a significant eosinophilic and neutrophilic inflammation as well as remodeling in IrIa many years after an inhalational accident.

Background: Forty to 70 cases of occupational asthma due to sensitization to an agent present in the workplace are accepted each year by the Commission de la santé et de la sécurité du travail, the Quebec medicolegal agency., Objectives and Methods: In a random sample of eight to 10 accepted claims per year from 1988 to 2002, the direct costs of compensation for loss of income (CLI) and compensation for functional impairment (CFI), as well as the associations of these costs with selected variables, were assessed., Results: Mean costs (presented as Canadian dollars x10(3)) of CLI, CFI and total were 72.5, 11.7 and 92.8, respectively, while the median costs were 40.7, 7.6 and 61.3 for CLI, CFI and total, respectively. Median CLI costs were significantly higher in men than women (69.9 versus 13.1), workers aged 40 years or older versus those younger than 40 years (90.1 versus 27.4), workers with occupational asthma due to workplace exposure to low versus high molecular weight agents (51.2 versus 38.6), and workers taking inhaled steroids at diagnosis (92 versus 52) and reassessment (81 versus 35). Median CFI costs were also higher in those requiring retraining (10.4) and taking early retirement (61.8) than workers who stayed with the same employer but in a different job (5.4). Median CFI costs were significantly higher for individuals being treated with inhaled steroids at the time of diagnosis (14.0 versus 5.2) and reassessment (13 versus 6), and for those left with bronchial hyperresponsiveness (9.5 versus 0.8) related to forced expiratory volume in 1 s and forced expiratory volume in 1 s/forced vital capacity., Conclusion: Age, sex, nature of occupational agent, treatment with inhaled steroids and type of rehabilitation all affect CLI, whereas lung function status at baseline and reassessment is related to CFI.

The diagnosis of occupational asthma can be made by exposing workers to the relevant agent either in a hospital laboratory through specific inhalation challenges (SICs) or in the workplace. As suggested by several authors, workers with negative laboratory SIC can be monitored at the workplace under supervision. The present study aims to assess the frequency of, and identify factors associated with, a positive workplace reaction in workers with negative SIC in the laboratory. The results of workplace challenges were examined in 99 workers who underwent negative SIC between 1994 and 2004. A positive reaction either in the SIC or in the workplace was defined as a sustained fall in forced expiratory volume in one second of > or =20%. In total, 22 (22.2%) workers showed positive responses at the workplace. These subjects more often had increased baseline methacholine responsiveness (90.5 versus 67.6%). They also underwent more days of SIC testing (4.9 versus 3.3 days) and were exposed more often to two or more agents (56 versus 28.4%) and for a longer period of time (363.3 versus 220.4 min) in the laboratory. The present study illustrates the usefulness of workplace monitoring of airway function in the investigation of occupational asthma and identifies factors that are more often associated with a positive reaction.

Rationale: We conducted a long-term (8-yr) follow-up of 408 apprentices entering programs involving exposure to high-molecular-weight allergens., Objectives: The objectives were to assess the frequency of new and persisting sensitization, symptoms, and bronchial hyperresponsiveness in relation with job history after ending apprenticeship and to examine characteristics significantly associated with the incidence and remission of these occupational outcomes., Methods: A respiratory symptom questionnaire, skin prick tests with work-related allergens (laboratory animals, flour, and latex), spirometry, and methacholine challenge were administered. The association between incidence or remission of these outcomes and individual characteristics at baseline and end of apprenticeship was examined., Measurements and Main Results: In subjects who at any time during follow-up held a job related to their training (78%), the incidence of sensitization, rhinoconjunctival and chest symptoms, and bronchial hyperresponsiveness at follow-up was 1.3, 1.7, 0.7, and 2.0 per 100 person-years, respectively. The remission of these outcomes acquired during apprenticeship was 18.5, 9.6, 9.6, and 12.4 per 100 person-years, respectively, in subjects no longer in a job related to training. Several clinical, immunological, and functional characteristics at baseline and acquired during apprenticeship were found to be significantly associated with the incidence and remission of the outcomes., Conclusions: The incidence of sensitization, symptoms, and bronchial hyperresponsiveness was lower while at work than during the apprenticeship period. A high proportion of subjects in a job not related to training experienced remission of symptoms acquired during apprenticeship.

Subjects with occupational asthma (OA) are often left with permanent sequelae after removal from exposure, and assessing their impairment/disability should utilise various tools. The aim of the present study was to examine whether: 1) assessment of inflammation in induced sputum is relevant to impairment; and 2) use of questionnaires on quality of life and psychological factors can be useful for the evaluation of disability. In total, 40 subjects were prospectively assessed for permanent impairment/disability due to OA 2 yrs after cessation of exposure. Impairment was assessed as follows: 1) need for asthma medication; 2) asthma severity; 3) airway calibre and responsiveness; and 4) degree of inflammation in induced sputum. Disability was assessed according to quality of life and psychological distress. There was a significant improvement in airway responsiveness and inflammation from diagnosis to the present assessment. Sputum eosinophils > or =2% and neutrophils >60% were present in eight (20%) and 12 (30%) out of all subjects, respectively, one or the other feature being the only abnormalities in 15% of subjects. Quality of life was moderately affected and there was a prevalence of depression and anxiety close to 50%. In the assessment of subjects with occupational asthma, information on airway inflammation and psychological impacts are relevant to the assessment of impairment/disability, although these findings need further investigation.

The present study assessed the usefulness of key items obtained from a clinical "open" questionnaire prospectively administered to 212 subjects, referred to four tertiary-care hospitals for predicting the diagnosis of occupational asthma (OA). Of these subjects, 72 (34%) were diagnosed as OA (53% with OA due to high-molecular-weight agents) according to results of specific inhalation challenges, and 90 (42%) as non-OA. Wheezing at work occurred in 88% of subjects with OA and was the most specific symptom (85%). Nasal and eye symptoms were commonly associated symptoms. Wheezing, nasal and ocular itching at work were positively, and loss of voice negatively associated with the presence of OA in the case of high-, but not low molecular-weight agents. A prediction model based on responses to nasal itching, daily symptoms over the week at work, nasal secretions, absence of loss of voice, wheezing, and sputum, correctly predicted 156 out of 212 (74%) subjects according to the presence or absence of OA by final diagnosis. In conclusion, key items, i.e. wheezing, nasal and ocular itching and loss of voice, are satisfactorily associated with the presence of occupational asthma in subjects exposed to high-molecular-weight agents. Therefore, these should be addressed with high priority by physicians. However, no questionnaire-derived item is helpful in subjects exposed to low-molecular-weight agents.

Objectives: To explore one aspect of the external validity of the randomized controlled trial (RCT), specifically how being selected for inclusion in a trial and having participated has influenced the use and cost of asthma-related health services., Methods: Services used by asthmatic users of inhaled corticosteroids (iCSTs) having previously participated in an RCT (TS, n = 46) were compared with individuals who had never participated (NS, n = 51)., Results: TS were more likely to use higher (> or = 400 microg) daily doses of iCSTs than NS (OR, 3.3; 95% Cl, 1.1-8.3) but less likely to visit emergency departments (OR, 0.3; 95% Cl, 0.1-0.7). Total asthma-related costs did not differ significantly., Conclusions: Subject differences may impede generalizing from RCTs to real life.

Serial peak expiratory flow (PEF) assessment has been proposed in the clinical evaluation of asthma. In subjects attending the asthma clinic of a tertiary care hospital, we wanted to assess: 1) compliance in performing PEF; and 2) accuracy of a PEF-diary. Twenty adult asthmatic subjects, all using inhaled steroids, were asked to assess their PEF in the morning and evening with a VMX instrument (Clement Clarke Int., Colombus, OH, USA). This instrument, which incorporates a standard mini-Wright peak flow meter, stores PEF data on a computer chip. Subjects were not informed that the values were being stored. The mean duration of PEF monitoring was 89 days (range 44-131 days). For the total of 20 subjects, it was estimated that 3,482 values should have been written down and stored on the VMX computer chip. Whilst 1,897 values (54%) were written down, only 1,533 (44%) were stored, 425 values being invented. Morning and evening values were stored on 34% of days; and values were stored at least once a day on 55% of days. The values written down corresponded precisely to stored values 90% of the time, and were within +/- 20 L 94% of the time. We conclude that: 1) compliance with daily peak expiratory flow assessments is generally poor in chronic stable asthmatic subjects assessed on two visits separated by a 3 month period; and 2) a substantial percentage of values (22%) is invented. The unsatisfactory compliance with peak expiratory flow monitoring in this group of asthmatics on inhaled steroids underlines the need for similar studies on peak expiratory flow monitoring as part of an action treatment plan, and in more severe and brittle asthmatics.

Airflow obstruction has been described in workers who experienced symptoms after acute exposure to chlorine. Persistent bronchial hyperresponsiveness has also been assessed, but mainly in case studies. In this cross-sectional study, we have assessed the relationship between inhalational accidents ("puffs") involving chlorine and persistent symptoms as well as hyperresponsiveness in 239 out of 255 at-risk workers (94%). No relationship was found between persistent symptoms and the exposure variables studied. Forced vital capacity (FVC) was higher in subjects who had had no symptoms after a "puff", compared with those who had experienced mild symptoms. Forced expiratory volume in one second (FEV1) and FVC were significantly lower in subjects who experienced more than 10 puffs with mild symptoms than in subjects who reported no symptomatic puff. The presence of bronchial hyperresponsiveness was not related to exposure, but the methacholine dose-response slope showed a tendency to increased bronchial responsiveness with increased exposure. A significant difference was shown in subjects who experienced more than 10 puffs with mild symptoms. In this group of workers, repeated exposure to chlorine with acute respiratory symptoms was associated with a slight but significant reduction in expiratory flow rates, together with an increase in bronchial responsiveness, without long-term symptoms.

Background: To confirm occupational asthma caused by clam and shrimp in a food company worker, the following investigation was planned in 60 other exposed workers (56 participants)., Methods: Before the production period of clam and shrimp, a medical and occupational questionnaire was carried out and skin and RAST testing were done with common inhalants and clam, shrimp, crab, and lobster extracts. During the production period, environmental monitoring was performed with personal and general samplers; inhalation testing with methacholine was proposed to subjects with immediate skin reactivity to clam, shrimp, or both. After the production period, all subjects with an immediate skin reactivity to clam, shrimp, or both and either a history of rhinoconjunctivitis, asthma, or bronchial hyperresponsiveness were seen by a specialist., Results: Including the index case in whom occupational asthma to clam and shrimp had been confirmed, four (7%) subjects had a history of rhinoconjunctivitis and two (4%) had a history of asthma during the period of clam production, whereas three (5%) subjects had rhinoconjunctivitis and two (4%) had asthma during the shrimp production. Three (5%) subjects had immediate skin reactivity to clam, and nine (16%) subjects to shrimp. Four (7%) subjects had increased specific IgE antibodies (RAST binding > or = 3%) to clam and eight (14%) to shrimp. Significant associations were found between immunologic reactivity to clam and shrimp on the one hand and to crab and lobster on the other. Environmental monitoring demonstrated clam and shrimp on the air sampling filters. Occupational asthma caused by clam was confirmed by specific inhalation challenges in one subject in addition to the index case. These two subjects had skin reactivity and increased specific IgE antibodies to clam, shrimp, or both., Conclusion: By including the initial subject, the prevalence of immediate sensitization is 5% to 7% to clam and 14% to 16% to shrimp. Two (4%) subjects had occupational asthma caused by clam, and one (2%) had occupational asthma caused by shrimp.

Background and Aim: Serial assessment of peak expiratory flow (PEF) rates has been advocated as a sensitive and specific means of investigating occupational asthma. The possibility that, for several reasons, subjects do not accurately report their values has been raised. The availability of portable instruments that assess PEF and store timings and values now make it possible to estimate compliance and accuracy of results., Methods: Twenty-one subjects consecutively investigated for occupational asthma were asked to assess their PEF every 2 hours during the day, both at work and away from work, with a VMX instrument (Clement Clarke International, Columbus, Ohio) and record the times and values on a sheet of paper. The subjects were not aware that the data were also being stored on a computer chip. The diagnosis was occupational asthma in eight subjects, personal asthma in four subjects, and neither condition in nine subjects., Results: The mean duration of recording was 36 days (range, 14 to 79 days). At least 6048 values should have been recorded, but only 4839 (80%) were either recorded or stored. Reported values corresponded precisely to stored values in 2533 of 4839 recordings (52%). The timing of the recording was also examined in relation to the time at which the recording was solicited; values recorded within 1 hour of the solicited time were judged as acceptable. Of the total of 3342 recordings stored, 2375 (71%) satisfied this criterion. Compliance was significantly less satisfactory in those referred by the Workers' Compensation Board (n = 11)., Conclusion: In this survey of 21 subjects investigated for possible occupational asthma, compliance with PEF recording, as assessed by comparing recorded and stored results and the time at which the recording was solicited, was poor.

Aims: The aim of this work was to compare the response to an inhaled beta 2-adrenergic agent in two situations: (1) spontaneous airway obstruction in asthmatic subjects who had withheld treatment with the medication for more than 12 hs; and (2) after methacholine-induced airway obstruction once airway caliber had recovered to the premethacholine test value., Subjects and Methods: Sixteen asthmatic subjects who showed a 20% or more improvement in FEV1 after inhaled beta 2-adrenergic agent (B2) (salbutamol, 200 micrograms) entered a double-blind crossover randomized trial in which the following tests were carried out: (1) FEV1 response after inhaling a placebo or active B2; (2) FEV1 response after inhaling a placebo or active B2 after a methacholine test that had induced a 20% or more reduction in FEV1, once FEV1 had recovered to the premethacholine value after inhaling salbutamol in an open fashion., Results: As expected, the mean percent improvement in FEV1 in the spontaneous airway obstruction situation was 21.7 +/- 8.5% after inhaling the active B2 and 2.2 +/- 1.8% after placebo B2 (p < 0.001). Following recovery after methacholine challenge, the FEV1 was slightly superior (mean difference of 146 mL) to the premethacholine value before inhaling the active or placebo B2. In this situation, the percent improvement in FEV1 after inhaling the active B2 was only 7.5 +/- 4.4% and not significantly different from after inhaling placebo B2 (4.9 +/- 5.4%). Consequently, the end FEV1 value after inhaling active B2 was significantly higher in a situation of spontaneous airway obstruction than after methacholine-induced airway obstruction (mean difference = 110 mL; p = 0.02)., Conclusion: After a methacholine test, the reversibility of an inhaled beta 2 agent is not significantly different from a placebo and is less satisfactory than in a situation of spontaneous airway obstruction. The mechanism for this needs to be explored but it is not secondary to persisting airway obstruction.

Aims: The aims of the study conducted on lawn cutters were: (1) to evaluate exposure to pollens and molds; and (2) to assess the prevalence rate of IgE sensitization and symptoms in relation to exposure to pollens and molds., Methods: Environmental assessment was done with the use of personal samplers on eight workers. Our population consisted of 181 municipal park workers, including 128 lawn cutters and 67 control subjects (blue-collar workers in the hospital). A questionnaire was administered, as well as skin prick tests with seven common inhalants including pollens and eight grass molds. The main outcome variables were grass or mold sensitization (at least one of eight molds) and work-related rhinitis, conjunctivitis, and rhinoconjunctivitis. Atopy and exposure to park-related allergens, as well as sensitization to grass pollens, were considered as explanatory factors. Smoking was taken into consideration as a covariant. Both presence and duration of occupational exposure to park-related allergens were considered as parameters of exposure. Duration of exposure (months x years of exposure as lawn cutters) was used as a continuous or as a categorical variable., Results: Environmental monitoring showed that the concentration of pollens and molds decreased in magnitude from samples collected close to lawn cutters faces, short distance away in parks, and in the general environment. There was no difference in the prevalence rates for atopy between lawn cutters (32%) and control subjects (37%). Sensitization rates to grass pollen were also similar in lawn cutters (18%) and in control subjects (22%). However, there was a tendency for prevalence rates of sensitization to molds to be greater among lawn cutters (12% to Alternaria) compared with control subjects (5%). In the logistic model atopy was significantly related to grass sensitization (odds ratio [OR] = 7.2), mold sensitization (OR = 9.3), and sensitization to Alternaria (OR = 5.8). Grass sensitization was a significant risk factor for park-related rhinitis (OR = 5.8), conjunctivitis (OR = 5.0), and rhinoconjunctivitis (OR = 9.4). Exposure for 12 years or more was associated with rhinoconjunctivitis with an OR of 4.1 (95% confidence interval, 1.0-16.7). Smoking was not significantly related to any outcome., Conclusion: We conclude that among lawn cutters exposure to pollens and molds is higher than in the general population, atopy is the main determinant of sensitization to these aeroallergens, and sensitization and, to a much lesser extent, exposure to grass are determinants of symptoms.

Background: Reactive airways dysfunction syndrome (RADS) or irritant-induced asthma is a syndrome that leaves subjects with asthma-like symptoms after one or more exposures to a high concentration of an irritant substance. The degree of reversibility of airway obstruction in subjects with RADS is nevertheless unknown, as is the degree of associated lesions at the airway level., Methods: We compared the acute reversibility of forced expiratory volume in 1 second (FEV1) after inhalation of albuterol (200 micrograms) in 15 subjects with RADS (12 cases caused by chlorine inhalation) with that of 30 subjects with occupational asthma (OA) caused by various agents. They were paired according to baseline airway obstruction (61% and 63% of predicted value in the RADS and OA groups), requirement for medication (bronchodilator only--7 of 15 subjects with RADS and 14 of 30 subjects with OA--as compared with bronchodilator + inhaled steroids in 8 of 15 subjects with RADS and 16 of 30 subjects with OA, respectively), and interval since removal from exposure (means of 30 and 24 months in the RADS and OA groups). In addition, five nonsmokers with RADS who had not received inhaled steroids underwent bronchoscopy with lavage and bronchial biopsies less than 2 years after the exposure., Results: The percentage increase in FEV1 over baseline after inhalation of albuterol was 10% +/- 9% in the RADS group and 19% +/- 16% in the OA group (p = 0.005). Only 2 of 15 subjects (13%) with RADS and 12 of 30 subjects (40%) with OA showed an improvement in FEV1 of 20% or greater after inhalation of albuterol. Bronchoalveolar lavage showed an increased number of cells with a predominance of lymphocytes, and biopsy specimens showed increased basement membrane thickness in the five subjects with RADS who underwent bronchoscopy., Conclusion: Subjects with RADS are generally left with less airway reversibility than those with OA. We suggest that this difference is secondary to distinct pathologic changes.

We previously showed in a retrospective study that the acute response to an inhaled beta-2-adrenergic agent is marked in late asthmatic reactions (J Allergy Clin Immunology 1990;85:834). In a double-blind prospective study, we assessed the magnitude and duration of the effect of inhaled salbutamol (200 micrograms) compared to a placebo in 22 subjects who experienced late asthmatic reactions (sustained fall in FEV 1 > or = 20%) after specific inhalation challenges in the laboratory with various occupational agents (isocyanates in 9 subjects). Before salbutamol was administered, the % in FEV1 over the pre-challenge values did not differ between the placebo (31 +/- 8%, n = 12) and the active (28 +/- 6%, n = 10) groups. The % recovery in FEV1 over the pre-bronchodilator value was 9 +/- 11% in the placebo group and 28 +/- 11% in the active group (t = 4.0, p < 0.001). The % recovery in FEV1 assessed in comparison with pre-challenge values was up to 80 +/- 17% in the placebo group and up to 95 +/- 6% in the active group (t = 2.85, p < 0.01). The 10 subjects on active medication had FEV1 values > or = 80% of the pre-challenge value one hour after inhaling salbutamol. The pattern of diminution in the bronchodilator effect was similar in the eight subjects with occupational asthma on active medication who remained for more than one hour as compared to a control group of asthmatic subjects paired for the degree of baseline airway obstruction. These data show that late asthmatic reactions are satisfactorily reversed with inhaled bronchodilator and that the duration of the effect is as satisfactory for subjects with occupational asthma as it is for asthmatic subjects.