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Prevalence and intensity of rhinoconjunctivitis in subjects with occupational asthma.

Subjects with occupational asthma may also report symptoms of rhinoconjunctivitis. The aims of this study were: 1) to assess the prevalence of rhinoconjunctivitis in association with occupational asthma, and the severity of rhinoconjunctivitis according to the type of agent (high (HMW) and low (LMW) molecular weight agents) causing occupational asthma; and 2) to evaluate the timing of occurrence of symptoms of rhinoconjunctivitis in relation to those of occupational asthma. A questionnaire on symptoms of rhinoconjunctivitis and its timing in relation to the development of chest symptoms was prospectively addressed to 143 subjects consecutively referred to an occupational asthma clinic. Objective testing through specific inhalation challenges confirmed the diagnosis of occupational asthma in 40 subjects. Symptoms of rhinitis were reported at some time by 37 of the 40 subjects (92%), and of conjunctivitis by 29 of the 40 subjects (72%). The prevalence of symptoms was not different for HMW and LMW agents, although rhinitis was more intense for HMW (19 out of 24 subjects with three or more of the following symptoms: runny nose, itchy nose, nasal blockage, and sneezing) than for LMW (5 out of 14 subjects) (p<0.01). There were significantly fewer subjects with occupational asthma due to LMW agents, with rhinitis appearing before asthma (p=0.03). Figures for conjunctivitis showed a similar trend, but did not reach statistical significance. In conclusion, symptoms of rhinoconjunctivitis are often associated with occupational asthma. Rhinitis is less pronounced in the case of low molecular weight agents, but more often appears before occupational asthma in the case of high molecular weight agents.

Compliance with and accuracy of daily self-assessment of peak expiratory flows (PEF) in asthmatic subjects over a three month period

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.

Natural history of sensitization, symptoms and occupational diseases in apprentices exposed to laboratory animals

The natural history of the development of sensitization and disease due to high-molecular-weight allergens is not well characterized. This study describes the time-course of the incidence of work-related symptoms, skin reactivity and occupational rhinoconjunctivitis (RC) and asthma (OA); and assesses the predictive value of skin testing and RC symptoms in apprentices exposed to laboratory animals, in a 3-4-yr programme. Four-hundred and seventeen apprentices at five institutions were assessed prospectively with questionnaire, skin-testing with animal-derived allergens, spirometry and airway responsiveness (n=373). Depending on the school, students were seen 8 (n=136), 20 (n=345), 32 (n=355) and 44 (n=98) months after starting the programme. At all visits, the incidence was greater for work-related RC symptoms followed in order by skin reactivity, occupational RC, and, almost equally, OA and work-related respiratory symptoms. The incidence-density figures were comparable for each follow-up period and for most indices up to 32 months after entry into the study and then tended to decrease. The positive predictive values (PPVs) of skin reactivity to work-related allergens for the development of work-related RC and respiratory symptoms were 30% and 9.0%, respectively, while the PPVs of work-related RC for the development of OA was 11.4%. Sensitization, symptoms and diseases occur maximally in the first 2-3 yrs after starting exposure to laboratory animals. Skin reactivity to work-related allergens and rhinoconjuctivitis symptoms have low positive predictive values.

What are the questionnaire items most useful in identifying subjects with occupational asthma

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.

Incidence of probable occupational asthma and changes in airway calibre and responsiveness in apprentice welders

The majority of cross-sectional studies have shown a higher prevalence of ventilatory impairment in welders while only few longitudinal studies were able to detect chronic effects on spirometry or bronchial responsiveness. The aim of the study was to determine the incidence of probable occupational asthma (OA), bronchial obstruction and hyperresponsiveness among 286 students entering an apprenticeship programme in the welding profession. This epidemiological prospective cohort study consisted of a baseline assessment survey and two follow-up assessments. A respiratory symptom questionnaire was administered at each visit. Spirometry and methacholine bronchial challenge test results, conducted once prior to onset of exposure and later after an average of 15 months of apprenticeship, were available for 194 subjects. The incidence of probable OA was ∼3% (6 of 194). The incidence of bronchial hyperresponsiveness, defined as a ≥3.2‐fold decrease in the provocative concentration causing a 20% fall in the forced expiratory volume in one second from baseline to the end of the study was 11.9%. A statistically significant difference was found between the baseline and end of study for the lung function values. In particular, the forced expiratory volume per cent predicted had significantly dropped by 8.4% on average. The significance of these early pulmonary function changes in relation to possible chronic effects of exposure to welding fumes and gases remains to be explored.

Incidence and host determinants of work‐related rhinoconjunctivitis in apprentice pastry‐makers

Background: The authors recently assessed the incidence and determinants of immunologic sensitization to flour in apprentice pastry‐makers. The aim of this work was to determine the incidence of work‐related rhinoconjunctivitis (RC) symptoms and their determinants.

Assessment of impairment/disability due to occupational asthma through a multidimensional approach

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 ≥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.

Assessment and evaluation of symptomatic steroid-naive asthmatics without sputum eosinophilia and their response to inhaled corticosteroids

Eosinophilic airway inflammation is one of the hallmarks of asthma. Sputum eosinophilia has been suggested as a predictor of the response to inhaled corticosteroids in asthma. This study sought to investigate the proportion of steroid-naive uncontrolled asthmatics without significant sputum eosinophilia (≤1%) and to examine whether sputum eosinophilia could predict the response to inhaled corticosteroids. A total of 51 mild uncontrolled steroid-naive asthmatics who had not been treated with oral or inhaled corticosteroids for at least 3 months were investigated. The evaluation included a spirometry, methacholine inhalation challenge and sputum induction on two occasions, one at baseline and the other after 1 month of treatment with 250 µg twice-daily fluticasone propionate. Of the 51 subjects, 15 had an eosinophil count ≤1%, and 46 completed the two visits. Patients with baseline sputum eosinophils ≤1% (n=14) were compared with those with sputum eosinophils >1% (n=32). The baseline characteristics of these two groups were similar. After 1 month of treatment, respiratory symptoms, quality of life, forced expiratory volume in one second (FEV1) and provocative concentration causing a 20% fall in FEV1 improved in both groups. The absence of sputum eosinophilia does not seem to be an indicator of poor response to inhaled corticosteroid treatment in steroid-naive asthmatics. However, this finding needs to be investigated further in a double-blind, placebo-controlled study, entirely designed to answer this question.

An ATS/ERS report: 100 key questions and needs in occupational asthma

The second Jack Pepys Workshop on Occupational Asthma was held in Toronto, Canada, in May 2004. The present report summarises key questions and research needs as identified by the international participants. The audiotapes from the workshop discussions were summarised by the organising chairs of the Symposium and the resulting document was circulated for input from all invited workshop participants. In total, 100 key questions and research needs were identified. Identified needs included: provision of different definitions depending on the use of data; explanations for differences in frequency studies; and better characterisation of genetic and environmental determinants of occupational asthma. The role of irritants and the pathogenesis of various forms of work-related asthma need further research, and there are also questions and research needs for diagnosis, prevention and understanding of persistence and airway remodelling. In conclusion, although advances have been made in the understanding of occupational asthma and other work-related asthma, further key issues remain that need addressing.

Detection of snow-crab antigens by air sampling of a snow-crab production plant

Background and objective We previously assessed the prevalence of occupational asthtna (OA) to snow‐crab in production plant workers. We also showed that this type of OA is related to immediate immunological reactivity as demonstrated by skin reactivity and increased specific IgE antibodies. However, we did not show that snow‐crab antigens causing immunological reactivity and OA could be found in the air sampling in the plants atmosphere. This was the purpose of the current work. Material and methods Area air samples worn by workers at four different worksites of a snow‐crab producing plant were obtained on PVC filters with an SKC pump run at 1.5 L/min for 2h. Snow‐crab was being boiled and processed during the air sampling periods. Filters were analysed by RAST inhibition in a blind manner (i.e. without knowledge of the worksite where the filter originated).