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Background Airway obstruction is a key feature of asthma and chronic obstructive pulmonary diseases (COPD). Smoking habits and workplace exposures to vapors, gas, dusts, and fumes (VGDF) could cause or exacerbate airway obstruction. The aim of this study is to evaluate the risk of airway obstruction due to smoking and workplace exposure, and their interaction, in a large population-based study. Methods In this cross-sectional study, a sample (n = 6153) of the Swedish population aged between 24 and 76 years underwent a questionnaire, clinical examination, blood test, and spirometry to gather information on airway obstruction classified by Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria or American Thoracic Society (ATS)/European Respiratory Society (ERS) criteria, risk factors, and confounders. Occupational exposures to VGDF were rated according to a specific job-exposure matrix. Adjusted logistic regression models were used to evaluate risk factors for airway obstruction in smokers and nonsmokers. Results In total, 9.8% had airway obstruction by GOLD criteria and 10.3% by ATS/ERS. Smokers with a high likelihood of exposure to VGDF had a higher risk of airway obstruction than those not exposed (odds ratio [OR]: 1.74, 95% confidence interval [CI]: 1.15-2.65 by GOLD; OR: 1.58, 95% CI: 1.06-2.37 by ATS/ERS) especially those >50 years of age. In smokers highly exposed to VGDF, risk estimates were higher than in the whole population, and the interaction between high exposure to VGDF and smoking further increased the risk of airway obstruction. Conclusions This study suggests a possible role for interaction between cigarette smoking and VGDF exposure on the risk of airway obstruction.

After observing several clinical patients with respiratory symptoms, we initiated a questionnaire survey to assess prevalence of and predictors for asthma and work-related symptoms among workers in fish processing plants. A questionnaire with items on work conditions, work-related symptoms, and respiratory symptoms/diseases was sent to 916 fish processing workers, the 1836 licenced fishermen in Sweden, and 1965 controls; of those, 43%, 57%, and 53%, respectively, responded. Risks, hazard ratios (HRs), and prevalence ratios (PRs) were calculated with Cox regression, and 95% confidence intervals (CIs) were computed. The risk of asthma among fish filleting workers was increased during the years working in the fish processing industry when compared to the other fish processing workers and controls (HR 3.6, 95% CI 1.6-8.1, adjusted for atopy, gender, and ever smoking). The filleters had an increased PR for most of the work-related respiratory symptoms investigated. All fish processing workers had a higher PR for flu-like symptoms. Use of a pressure sprayer was identified as a risk for asthma and respiratory symptoms among both fish processing workers and controls. Filleters had changed work tasks because of respiratory symptoms more often (Fisher's exact test, p = 0.02) than other fish processing workers. In conclusion the fish filleters and pressure sprayer users reported more adult asthma and cough with phlegm compared to the other fish processing workers and controls. The use of pressure sprayers must be reduced and machinery should be completely encased to reduce workers' exposure to bioaerosols and its effects on the respiratory tract.

ObjectivesOccupational exposures to metal fumes have been associated with increased pneumonia risk, but the risk of invasive pneumococcal disease (IPD) has not been characterised previously.MethodsWe studied 4438 cases aged 20–65 from a Swedish registry of invasive infection caused by Streptococcus pneumoniae. The case index date was the date the infection was diagnosed. Six controls for each case, matched for gender, age and region of residency, were selected from the Swedish population registry. Each control was assigned the index date of their corresponding case to define the study observation period. We linked cases and controls to the Swedish registries for socioeconomic status (SES), occupational history and hospital discharge. We applied a job–exposure matrix to characterise occupational exposures. We used conditional logistic analyses, adjusted for comorbidities and SES, to estimate the OR of IPD and the subgroup pneumonia–IPD, associated with selected occupations and exposures in the year preceding the index date.ResultsWelders manifested increased risk of IPD (OR 2.99, 95% CI 2.09 to 4.30). Occupational exposures to fumes and silica dust were associated with elevated odds of IPD (OR 1.11, 95% CI 1.01 to 1.21 and OR 1.33, 95% CI 1.11 to 1.58, respectively). Risk associated with IPD with pneumonia followed a similar pattern with the highest occupational odds observed among welders and among silica dust exposed.ConclusionWork specifically as a welder, but also occupational exposures more broadly, increase the odds for IPD. Welders, and potentially others with relevant exposures, should be offered pneumococcal vaccination.

Background: Occupational exposures to metal fumes and inorganic dust have been associated with increased pneumonia risk, but the risk of invasive pneumococcal disease (IPD) has not been characterized previously. Methods: We studied 4 438 cases 20 to 65 years of age from a Swedish national registry of invasive infection caused by Streptococcus pneumoniae. The case index date was the day the infection was diagnosed. Six controls for each case, matched for gender and age, were selected from the Swedish population registry. Each control was assigned the index date of their corresponding case to define the study observation period. We linked cases and controls to the Swedish registries for socioeconomic status (SES), occupational history, hospital discharge and mortality. We applied a job-exposure matrix (JEM) to characterize occupational exposures. We used conditional logistic analyses, adjusted for co-morbidities and SES, to estimate the odds ratio (OR) of IPD and the subgroup with pneumonia, associated with selected occupations and exposures the year before index date. Results: Welders manifested increased risk of IPD (OR 2.99, 95% confidence interval (CI) 2.09 - 4.30). Occupations likely to have exposure to fumes based on a JEM-assignment were also associated with elevated odds of IPD (OR 2.40, 95% CI 1.72-3.36). Risk associated with IPD with pneumonia followed a similar pattern with the highest occupational odds observed among welders (OR 3.28, 95% CI 2.22-4.84). Conclusions: Work as welder and occupational exposure to fumes increase the odds for IPD. Welders and potentially others with relevant exposures should be offered pneumococcal vaccination. Funding Statement: Swedish Heart and Lung Foundation, Swedish Council for Working Life, Health, and Welfare (FORTE) and by grants from the Swedish state under the agreement between the Swedish government and the county councils, the ALF-agreement, 74570. Declaration of Interests: All authors have completed the Unified Competing Interest form at www.icmje/coi_disclosure.pdf (available in request from the corresponding author): KT, IQ, OA, NM, RN, ADH, PDB and LS do not have any conflict of interest to report. Ethical Approval Statement: The Gothenburg Committee of Ethics approved the study (Dnr 729-16).

Asthma often remains uncontrolled, despite the fact that the pharmacological treatment has undergone large changes. We studied changes in the treatment of asthma over a 20-year period and identified factors associated with the regular use of inhaled corticosteroid (ICS) treatment. Changes in the use of medication were determined in 4617 randomly selected subjects, while changes in adults with persistent asthma were analysed in 369 participants. The study compares data from three surveys in 24 centres in 11 countries. The use of ICSs increased from 1.7% to 5.9% in the general population and the regular use of ICSs increased from 19% to 34% among persistent asthmatic subjects. The proportion of asthmatic subjects reporting asthma attacks in the last 12 months decreased, while the proportion that had seen a doctor in the last 12 months remained unchanged (42%). Subjects with asthma who had experienced attacks or had seen a doctor were more likely to use ICSs on a regular basis. Although ICS use has increased, only one-third of subjects with persistent asthma take ICSs on a regular basis. Less than half had seen a doctor during the last year. This indicates that underuse of ICSs and lack of regular healthcare contacts remains a problem in the management of asthma., Despite increased ICS use, only 34% of subjects with persistent asthma take ICSs on a regular basis

Objective: Hairdressers have an increased risk for airway symptoms especially when using hair-bleaching powder containing persulfate. To minimize exposure, dust-free bleaching powder (DFP) has been made available. We studied the effects of regular powder (RP) or DFP on the airway symptoms of hairdressers with hair-bleaching associated rhinitis. Methods: Twelve hairdressers each performed three hair-bleachings on a wig in an exposure chamber. Half of the subjects used RP and half used DFP. Exposure to persulfate and ammonia was measured. Before and after each bleaching, the participants stated their degree of airway symptoms on a visual analogue scale. Nasal lavage and blood were sampled before exposure, after the last bleaching, and in the morning after exposure to measure inflammatory markers. Results: Exposure to persulfate was higher when using RP compared to DFP, 22 (11-55) vs. 12 (8-13) μg/m3; median (min-max). Exposure to ammonia did not differ between the groups. Both groups reported an increase in asthma-like symptoms and this increase was significant. Neutrophils, lymphocytes, and monocytes increased after exposure in both groups; monocytes decreased the day after. In nasal lavage, IL-8 was increased the morning after for both types of powder, and the increase was significant in the total group. IL-6 increased immediately after exposure and the day after only in the group using RP. Conclusions: Although DFP powder emits lower levels of persulfate, effects are still elicited in symptomatic hairdressers.

WORK-RELATED ASTHMA comprises occupational asthma (OA) that is caused by conditions at work and work-exacerbated asthma (WEA), in which existing asthma is made worse by workplace conditions.1 Work-related asthma is common, with work accounting for an average 16.9% of all new adult-onset asthma cases,2 and with WEA detected in an estimated 21.5% of working adults with asthma.3 While substantial costs and lost work time are associated with both WEA and OA,4,5 WEA has received less attention in terms of research and prevention efforts.1 WEA is potentially preventable by minimizing harmful workplace exposures,3 but a better understanding of which agents pose a risk is needed to guide prevention efforts. While surveillance in the United States indicates that WEA is frequently caused by irritants, low molecular weight (e.g., acids, bases, aldehydes) and high molecular weight (e.g., latex) agents are also implicated.6 The absence of denominators (i.e., the number of workers exposed) prohibits using surveillance data to estimate agent-specific risk. We used data from a previous study to identify occupational risk factors for exacerbation of asthma.7 In previous analyses of data from this study, we determined WEA status on a case-by-case basis. However, for the current investigation, we modeled severe exacerbation of asthma and determined which occupational exposures were associated with it, while simultaneously controlling for potential confounders. We assessed occupational exposures using a new asthma-specific job-exposure matrix (JEM).8

Background Exposure to allergen may induce a modified T H 2 response characterized by high IgG 4 levels, absence of IgE sensitization, and a decreased risk of allergic respiratory symptoms. Objective To assess the association of IgG 4 level with allergic respiratory symptoms in a community-based sample of adults. Methods Information on exposure to cats, respiratory symptoms, and mattress allergen levels was obtained from 2780 adults. Levels of cat and house dust mite (HDM) specific IgE, IgG, and IgG 4 were measured. The association of exposure to allergen with IgG 4 and of IgG 4 with symptoms was assessed. Results Geometric mean (GM) cat specific IgG and IgG 4 was higher in subjects who had a cat that was allowed in the bedroom than in subjects without a cat (adjusted ratio of GM IgG 4 , 1.41; 95% CI, 1.25-1.57). Levels of HDM specific IgG and IgG 4 were similar in subjects with undetectable and high (>20.22 μg/g) mattress Der 1 levels (adjusted ratio of GM IgG 4 , 1.02; 95% CI, 0.89-1.17). There was no evidence that high cat or HDM specific IgG 4 levels were associated with less IgE sensitization or with fewer symptoms. Conclusion In this community-based sample of adults, high IgG 4 levels to cat or HDM were not associated with a lower risk of allergic respiratory symptoms. Clinical implications In adults, high cat allergen exposure does not protect against respiratory symptoms.

An association between indoor dampness and respiratory symptoms has been reported, but dampness as a risk factor for the onset or remission of respiratory symptoms and asthma is not well documented.This follow up study included 16 190 subjects from Iceland, Norway, Sweden, Denmark, and Estonia who had participated in the European Community Respiratory Health Survey (ECRHS I). Eight years later the same subjects answered a postal questionnaire that included questions on respiratory symptoms and indicators of indoor dampness.Subjects living in damp housing (18%) had a significantly (p0.001) higher prevalence of wheeze (19.1% v 26.0%), nocturnal breathlessness (4.4% v 8.4%), nocturnal cough (27.2% v 36.5%), productive cough (16.6% v 22.3%) and asthma (6.0% v 7.7%). These associations remained significant after adjusting for possible confounders. Indoor dampness was a risk factor for onset of respiratory symptoms but not for asthma onset in the longitudinal analysis (OR 1.13, 95% CI 0.92 to 1.40). Remission of nocturnal symptoms was less common in damp homes (OR 0.84, 95% CI 0.73 to 0.97).Subjects living in damp housing had a higher prevalence of respiratory symptoms and asthma. Onset of respiratory symptoms was more common and remission of nocturnal respiratory symptoms was less common in subjects living in damp housing.

Background Airway diseases in hairdressers are a concern. The objective of this investigation is to evaluate the risk for three respiratory symptoms, wheeze, dry cough, and nasal blockage, in hairdressers. Methods A questionnaire on respiratory symptoms, atopy, smoking, and work history was answered by 3,957 female hairdressers and 4,905 women from the general population as referents. Incidence rates (IR) and incidence rate ratios (IRRs)for the three symptoms were estimated. Results The IRs of all three studied symptoms were higher in the hairdressers compared with the referents. Smoking modified the effects of cohort affiliationfor all threesymptoms; the combined effect from hairdressing work and smoking was less than expected. In addition, the effect of cohort affiliation for wheeze was also modified by atopy, and the effect of cohort affiliation for nasal blockage was also modified by calendar year. Conclusions Hairdressing work was associated with increased incidences of respiratory symptoms. Smoking had a negative modifying effect.

OBJECTIVE We have recently published a study on new-onset asthma in a large population in northern Europe using a modified job exposure matrix (N-JEM) to better reflect exposure assignment in these countries. The aim of this paper was to investigate how the N-JEM differs in exposure assignment and asthma risks from an already established JEM. METHOD The study comprised 6253 men and 7031 women from northern Europe, born 1945-1973, who had answered both a screening (1989-1992) and a follow-up questionnaire (1999-2001). During the study period (1980-2000), there were 136 men and 293 women with new-onset asthma. Hazard ratios of new-onset asthma were calculated for both JEMs using Cox regression models. The analyses were made separately for men and women and were also stratified for atopy. Cohen's kappa (κ) was used to show agreements in exposure assignment (yes/no) between the JEMs. Population attributable risks (PARs) were calculated as well. RESULTS The agreement in exposure assignment between the JEMs was substantial for the group 'any exposure' to asthma agents (κ = 0.78). The agreement between comparable exposure groups in the JEMs varied from κ = 1.00 (pharmaceutical product antigens, textile dust, cleaning agents) to κ = 0.27 (low molecular weight agents). Significant increased asthma risks were seen for men exposed to isocyanates and accidental peak exposure with both JEMs. With the N-JEM, increased asthma risks were seen for men exposed to plant-associated antigens (all and non-atopic), epoxy compounds (all and non-atopic), and acrylates (non-atopic). With the other JEM, increased asthma risks were seen in men and women exposed to 'possible exposure to irritant gases or fumes' (all and non-atopic), a group classified as having low asthma risk. Men and women exposed to cleaning agents also showed significant asthma risks with both JEMs. PAR with the N-JEM was 14.3% for men and 6.6% for women, compared with 12.9% and 8.3% with the other JEM. CONCLUSIONS Acrylates, epoxy compounds, and isocyanates are three exposure groups in the modified asthma JEM that might better reflect exposure situations in northern Europe than the already established JEM. Exposure to 'possible exposure to irritant gases or fumes', a low asthma risk group in the established JEM, seems to be a group with high asthma risk in northern Europe. It is important to continuously update JEMs, which are based only on occupational titles, in order to find new risk groups and to better reflect changes in work exposures when old risks disappear and new emerge.

OBJECTIVES: In a large population-based study among adults in northern Europe the relation between occupational exposure and new-onset asthma was studied. METHODS: The study comprised 13 284 subjects born between 1945 and 1973, who answered a questionnaire 1989-1992 and again 1999-2001. Asthma was defined as 'Asthma diagnosed by a physician' with reported year of diagnose. Hazard ratios (HR), for new-onset adult asthma during 1980-2000, were calculated using a modified job-exposure matrix as well as high-risk occupations in Cox regression models. The analyses were made separately for men and women and were also stratified for atopy. RESULTS: During the observation period there were 429 subjects with new-onset asthma with an asthma incidence of 1.3 cases per 1000 person-years for men and 2.4 for women. A significant increase in new-onset asthma was seen for men exposed to plant-associated antigens (HR = 3.6; 95% CI [confidence interval] = 1.4-9.0), epoxy (HR = 2.4; 95% CI = 1.3-4.5), diisocyanates (HR = 2.1; 95% CI = 1.2-3.7) and accidental peak exposures to irritants (HR = 2.4; 95% CI = 1.3-4.7). Both men and women exposed to cleaning agents had an increased asthma risk. When stratifying for atopy an increased asthma risk were seen in non-atopic men exposed to acrylates (HR = 3.3; 95% CI = 1.4-7.5), epoxy compounds (HR = 3.6; 95% CI = 1.6-7.9), diisocyanates and accidental peak exposures to irritants (HR = 3.0; 95% CI = 1.2-7.2). Population attributable risk for occupational asthma was 14% for men and 7% for women. CONCLUSIONS: This population-based study showed that men exposed to epoxy, diisocyanates and acrylates had an increased risk of new-onset asthma. Non-atopics seemed to be at higher risk than atopics, except for exposure to high molecular weight agents. Increased asthma risks among cleaners, spray painters, plumbers, and hairdressers were confirmed.

Antigen presentation determines immunologic outcome, and by modifying the presentation of allergen to the host one can prevent an allergic response. Under certain conditions, covalent linkage, of ovalbumin to rat IgG, a molecule already tolerated by the host, can make a protein-IgG conjugate which down-regulates the immune response to this food allergen. The suppression is allergen specific. It affects both T and B cell immune responses. Administration of allergens linked to isologous IgG may provide a novel strategy for allergy prevention.

Background There is conflicting evidence whether nasal nitric oxide (NO) is associated with current rhinitis and with other possible predictors. Most studies have been performed in clinical cohorts and there is a lack of studies based on a general population sample. The aim of the present study was to investigate predictors for levels of nasal nitric oxide (NO) in a general population. Methods The population consisted of 357 subjects from Gothenburg participating in the follow-up of the European Respiratory Health Survey in 1999-2001. All subjects completed an extensive respiratory questionnaire. Nasal NO was measured from one nostril at a time with a sampling rate of 50 mL/s for 16 seconds and the nasal NO concentration was determined as the mean value within the plateau phase. Mattress dust samples were collected for cats and mites in a subsample of subjects. Ambient and exhaled NO was also measured. The predictors for nasal NO were analyzed in multiple linear regression models. Results There was no relation between the levels of nasal NO and reporting current rhinitis. Nasal NO was significantly increased among those with high levels of IgE against cats and current smokers had significantly lower nasal NO. There was also a positive association between ambient NO and nasal NO. There were no significant associations between nasal NO and sex, age, or height, or between nasal NO and measured levels of cat antigen. Conclusion In this general population sample we found no relation between current rhinitis and nasal NO levels. There was a clear association between sensitization to cat and nasal NO, but there was no relation to current exposure to cat allergen. Our data support that nasal NO has a limited value in monitoring upper airway inflammation.

Background This investigation was triggered by three cases of asthma—about 10% of the workforce—occurring in a salmon processing plant over a short period of time. The aim of the investigation was to characterize the work exposure of inhalable organic particles with personal measurements. Respiratory symptoms at work among workers were also assessed. Methods Exposures to airborne salmon allergen, airborne mold spores, and endotoxin in water and air were measured during work. To assess the Atlantic salmon (Salmo salar) Sal s 1 allergen exposure a polyclonal sandwich enzyme-linked immunosorbent assay (ELISA) was developed. Current workers (n = 26) answered questionnaires and underwent allergy and lung function tests. Results Using the sensitive ELISA method (0.05 ng/ml), we found that workers were exposed to high levels of salmon major allergen at the filleting machine and at the filleting table. Airborne endotoxin levels were low, and mold levels were elevated. Only the three initial asthma cases had IgE to salmon. Of the other workers, 65% reported respiratory symptoms at work. These had lower pulmonary function than workers without such symptoms. Conclusions We developed a sensitive method to measure salmon antigen in air and found that filleting workers were most exposed. It is important to reduce aerosols by improving the ventilation system, machines and organization of work since respiratory symptoms at work among workers were common. Am. J. Ind. Med. 55:624–630, 2012. © 2012 Wiley Periodicals, Inc.

Background The primary aim of the present study was to investigate if exposure to dust from absorbent hygiene products containing superabsorbent polymer is related to symptoms from the airways and from the eyes. The secondary aim was to estimate the current exposure to superabsorbent polymer among production and maintenance workers in a plant producing hygiene products. Methods The cohort comprised 1043 workers of whom 689 were exposed to super absorbent polymer and 804 were exposed to paper dust (overlapping groups). There was 186 workers not exposed to either superabsorbent polymer or to paper dust They were investigated with a comprehensive questionnaire about exposure, asthma, rhinitis and symptoms from eyes and airways. The results were analyzed with logistic regression models adjusting for sex, age, atopy and smoking habits. An aerosol sampler equipped with a polytetrafluoroethylene filter with 1 μm pore size was used for personal samplings in order to measure inhalable dust and superabsorbent polymer. Results The prevalence of nasal crusts (OR 1.4, 95% CI 1.01-2.0) and nose-bleeding (OR 1.7, 95% CI 1.2-2.4) was increased among the paper dust exposed workers (adjusted for superabsorbent polymer exposure). There were no significant effects associated with exposure to superabsorbent polymer (adjusted for paper dust exposure). The average exposure to inhalable levels of total dust (paper dust) varied between 0.40 and 1.37 mg/m3. For superabsorbent polymer dust the average exposure varied between 0.02 and 0.81 mg/m3. Conclusions In conclusion, our study shows that workers manufacturing diapers in the hygiene industry have an increased prevalence of symptoms from the nose, especially nose-bleeding. There was no relation between exposure to superabsorbent polymer and symptoms from eyes, nose or respiratory tract, but exposure to paper dust was associated with nose-bleeding and nasal crusts. This group of workers had also a considerable exposure to superabsorbent polymer dust.

Objectives Two spa workers reported symptoms such as fever, shivering, palpitation, arthralgia, and diarrhea after performing seaweed massages on clients at a spa center. This study was carried out to determine whether the symptoms were related to exposure to endotoxin. Methods Personal and stationary air sampling for the measurement of airborne endotoxin was carried out at the spa during the preparation of a bath and the following seaweed massage. In addition, the impact of storage time on the concentration of endotoxin in the seaweed was investigated. Results The measurements confirmed exposure to aerosolized endotoxin at the spa (11 ng/m^2 and 22 ng/m^3). The endotoxin concentration in the stored seaweed increased as the storage time increased, from 360 ng/g seaweed for fresh seaweed to 33 100 ng/g seaweed for seaweed stored for ＞20 weeks. Conclusions Organic dust toxic syndrome was diagnosed for two workers who performed seaweed massages at a spa center at which aerosolized endotoxin was measured. In order to minimize entotoxin exposure during massages, it is important to use fresh seaweed or seaweed kept well cooled for no more than 2-3 weeks.

Rationale: Cleaning work and professional use of certain cleaning products have been associated with asthma, but respiratory effects of nonprofessional home cleaning have rarely been studied. Objectives: To investigate the risk of new-onset asthma in relation to the use of common household cleaners. Methods: Within the follow-up of the European Community Respiratory Health Survey in 10 countries, we identified 3,503 persons doing the cleaning in their homes and who were free of asthma at baseline. Frequency of use of 15 types of cleaning products was obtained in a face-to-face interview at follow-up. We studied the incidence of asthma defined as physician diagnosis and as symptoms or medication usage at follow-up. Associations between asthma and the use of cleaning products were evaluated using multivariable Cox proportional hazards or log-binomial regression analysis. Measurements and Main Results: The use of cleaning sprays at least weekly (42% of participants) was associated with the incidence of asthma symptoms or medication (relative risk [RR], 1.49; 95% confidence interval [CI], 1.1221.99) and wheeze (RR, 1.39; 95% CI, 1.0621.80). The incidence of physician-diagnosed asthma was higher among those using sprays at least 4 days per week (RR, 2.11; 95% CI, 1.1523.89). These associations were consistent for subgroups and not modified by atopy. Dose–response relationships (P , 0.05) were apparent for the frequency of use and the number of different sprays. Risks were predominantly found for the commonly used glass-cleaning, furniture, and air-refreshing sprays. Cleaning products not applied in spray form were not associated with asthma. Conclusions: Frequent use of common household cleaning sprays may be an important risk factor for adult asthma.

Objective: The authors examined the relations between self-reported work tasks, use of cleaning products and latex glove use with new-onset asthma among nurses and other healthcare workers in the European Community Respiratory Health Survey (ECRHS II). Methods: In a random population sample of adults from 22 European sites, 332 participants reported working in nursing and other related healthcare jobs during the nine-year ECRHS II follow-up period and responded to a supplemental questionnaire about their principal work settings, occupational tasks, products used at work and respiratory symptoms. Poisson regression models with robust error variances were used to compare the risk of new-onset asthma among healthcare workers with each exposure to that of respondents who reported professional or administrative occupations during the entire follow-up period (n=2481). Results: Twenty (6%) healthcare workers and 131 (5%) members of the referent population reported new-onset asthma. Compared to the referent group, the authors observed increased risks among hospital technicians (RR 4.63; 95% Cl 1.87 to 11.5) and among those using ammonia and/or bleach at work (RR 2.16; 95% Cl 1.03 to 4.53). Conclusions: In the ECRHS II cohort, hospital technicians and other healthcare workers experience increased risks of new-onset current asthma, possibly due to specific products used at work.

Summary Background The role of exposure to substances in the workplace in new-onset asthma is not well characterised in population-based studies. We therefore aimed to estimate the relative and attributable risks of new-onset asthma in relation to occupations, work-related exposures, and inhalation accidents. Methods We studied prospectively 6837 participants from 13 countries who previously took part in the European Community Respiratory Health Survey (1990–95) and did not report respiratory symptoms or a history of asthma at the time of the fi rst study. Asthma was assessed by methacholine challenge test and by questionnaire data on asthma symptoms. Exposures were defi ned by high-risk occupations, an asthma-specifi c job exposure matrix with additional expert judgment, and through self-report of acute inhalation events. Relative risks for new onset asthma were calculated with log-binomial models adjusted for age, sex, smoking, and study centre. Findings A signifi cant excess asthma risk was seen after exposure to substances known to cause occupational asthma (Relative risk=1·6, 95% CI 1·1–2·3, p=0·017). Risks were highest for asthma defi ned by bronchial hyper-reactivity in addition to symptoms (2·4, 1·3–4·6, p=0·008). Of common occupations, a signifi cant excess risk of asthma was seen for nursing (2·2, 1·3–4·0, p=0·007). Asthma risk was also increased in participants who reported an acute symptomatic inhalation event such as fi re, mixing cleaning products, or chemical spills (RR=3·3, 95% CI 1·0–11·1, p=0·051). The population-attributable risk for adult asthma due to occupational exposures ranged from 10% to 25%, equivalent to an incidence of new-onset occupational asthma of 250–300 cases per million people per year. Interpretation Occupational exposures account for a substantial proportion of adult asthma incidence. The increased risk of asthma after inhalation accidents suggests that workers who have such accidents should be monitored closely.

This study assessed paternal occupational exposure to di(2-ethylhexyl)phthalate (DEHP) in association with reduced fertility.Men working in three plants with DEHP exposure were studied retrospectively. Male and female employees and their partners were invited to participate if they had reported a pregnancy or an attempt to achieve a pregnancy. Postal questionnaires and telephone interviews were used to collect additional data from the men and women, respectively. Information on time to pregnancy was eligible for 326 pregnancies fathered by 193 men. Male exposure to DEHP during every month of their time to pregnancy was classified into one of three exposure categories. The exposure ranged from0.1 to 2.1 mg/m3. The fathers of only four pregnancies had DEHP exposure of0.5 mg/m3 during the time to pregnancy. The pregnancies of employed women with unexposed partners or pregnancies of employed men unexposed during the time to pregnancy formed the reference group.The fecundability ratio for time to pregnancy was 1.07 [95% confidence interval (95% CI) 0.84-1.35] for those with low exposure and 0.97 (95% CI 0.70-1.33) for the highly exposed after adjustment for the father's age, mother's age, and length of recall. When the analyses were restricted to first pregnancy, the fecundability ratio was 1.13 (95% Cl 0.83-1.56) for low exposure and 1.02 (95% CI 0.66-1.59) for high exposure.Time to pregnancy is not prolonged among couples with paternal exposure to DEHP at a mean exposure level of0.5 mg/m3.

Background: Objective tools are lacking for the diagnosis of local gastrointestinal inflammatory reactions in skin prick test (SPT)-negative and serum IgE antibody (s-IgE Ab)-negative patients with suspected food allergy. Objective : The purpose of this investigation was to evaluate the presence of eosinophils, T cells, local IgE-bearing cells, IL-4, and IFN-γ in small intestinal biopsy specimens from adult SPT-negative/s-IgE Ab-negative patients with food allergy during symptomatic and nonsymptomatic periods. Methods : Fourteen patients with food allergy-related gastrointestinal symptoms confirmed by double-blinded, placebo-controlled food challenge (DBPCFC) were investigated. Eleven of the patients were SPT-negative and s-IgE Ab-negative. Sex- and age-matched healthy volunteers were used as controls. Duodenal biopsies were studied with immunostaining through use of a panel of mouse monoclonal antibodies specific for eosinophils, CD3, CD4, CD8, IgE, IL-4, and IFN-γ. Results : Significant increases in numbers of MBP + eosinophils, IgE-bearing cells, and T cells were found in the duodenal mucosa of the patients when they were symptomatic in comparison with when they were asymptomatic and in comparison with healthy controls. Numbers of IL-4 + cells were increased and numbers of IFN-γ + cells were reduced in the patients when they were symptomatic in comparison with when they were asymptomatic and in comparison with the controls. There were no differences in total s-IgE levels between any of the groups. Conclusion : A significant correlation was found between the appearance of symptoms of food hypersensitivity and the duodenal presence of IgE-bearing cells, activated eosinophils, and T cells in patients with negative SPT results and negative s-IgE Ab to the offending food. We suggest that a localized IgE-mediated response caused the gastrointestinal symptoms seen in these patients. (J Allergy Clin Immunol 2002;109:879-87.)

OBJECTIVE: To investigate the risk of asthma in hairdressers. METHODS: The incidence of asthma was retrospectively estimated in a Swedish nationwide study including all female hairdressers certified from vocational schools from 1970 to 1995, and a stratified sample of women from the general population were referents. A postal questionnaire included questions on respiratory tract symptoms, atopy, smoking, working periods as a hairdresser, and number of specific hair treatments performed/week. Reported exposures were validated by occupational hygienists. Rate ratios of incidence (IRRs) of asthma were estimated by Poisson regression, adjusted for calendar year of observation, hay fever, smoking, and region of domicile. RESULTS: The crude incidences of asthma/1000 person-years were: 3.9 during active years as a hairdresser, 2.8 among the hairdressers when not working in the profession, and 3.1 among the referents. The corresponding IRR for being an active hairdresser compared with the referents was 1.3 (95% confidence interval (95% CI) 1.0 to 1.6). Moderate effects on risk of asthma were found both from hairdressing work (IRR=1.6 (1.1 to 2.2) among never-smokers) and from smoking (IRR=1.6 (1.2 to 2.2) among referents). However, the combined effect from hairdressing work and smoking (IRR=1.5 (1.0 to 2.1)) was less than expected (p=0.02). No effect modification by respiratory atopy was found. The hairdressers most often performing hair bleaching treatments (IRR=1.5 (0.7 to 3.0)) or using hair spray (IRR=1.4 (0.8 to 2.4)) had, compared with the most infrequent users, a slightly, but not significantly higher incidence of asthma. Exposure to persulphates in hair bleach was estimated to be 0.04-0.15 mg/m(3) during mixing of the powder. Reported average number of bleaching treatments agreed well with those performed according to a diary. CONCLUSIONS: Active hairdressing work was associated with a moderately increased incidence of asthma among lifelong non-smokers. The results are moderately supportive, but not conclusive, of associations between asthma and exposure to hair bleach or hair spray.

The more evidence that accumulates, the more complex the immune system appears. Only a simple outline will be presented here as background to the discussion. The antigen-presenting cells (APCs) are crucial because they are required for initiation of immune responses to all protein antigens. In the gut the active APCs are dendritic cells and macrophages. It has been debated whether gut epithelial cells can function as APCs; the evidence is still incomplete. APCs degrade the protein and present peptides in their inherited human leukocyte antigens (HLA) class I1 surface molecules to CD4+ T helper (TH) lymphocytes (Figure 1). They can only present peptides that fit the grooves in their HLA class I1 molecules, and the T cell is HLA restricted in recognizing this complex. Thus, immune responses are HLA dependent. The immune response will primarily develop into cell-mediated immunity if the TH cell binding the HLA-peptide complex with its T-cell receptor is exposed to the cytokine interleukin (1L)-12. In that case, the T H cell will turn into a TH type 1 (TH1) cell, which primarily produces the cytokines interferon (1FN)-y, IL-2, and tumor necrosis factor (TNF)-a. The IFN-y will activate macrophages able to kill intracellular parasites such as viruses, fungi, and certain bacteria like Listeria and Salmonella typhi. Cytotoxic CD8+ T cells (T,) also develop, using IL-2 for activation. The TH1 thus stimulates cellmediated immunity, which can also bring about antitumor activity. If, on the other hand, the TH cell is mainly exposed to IL-10, a TH2 cell, which chiefly produces IL-4, IL-5, IL-6, and IL-10, will develop. These cy

Summary Background External agents, especially metal and wood dust, are believed to be risk factors for development of idiopathic pulmonary fibrosis (IPF). The aim of this case–control study was to investigate which occupational exposure types are associated with development of severe pulmonary fibrosis (PF), and especially IPF. Methods An extensive postal questionnaire including 30 specific items regarding occupational exposure was completed by 181 patients with severe PF and respiratory failure reported to the Swedish Oxygen Register, among whom 140 were judged as having IPF. The questionnaire was also completed by 757 control subjects. We stratified data for age, sex and smoking and calculated odds ratios (ORs). Results We found increased risk for IPF in men with exposure to birch dust (OR 2.7, 95% confidence interval (95% CI) 1.30–5.65) and hardwood dust (OR 2.7, 95% CI 1.14–6.52). Men also had slightly increased ORs associated with birds. We did not find any increased risk in association with metal dust exposure. Conclusion Exposure for birch and hardwood dust may contribute to the risk for IPF in men.