Respiratory diseases and allergy in farmers working with livestock: a EAACI position paper.

Farmers constitute a large professional group worldwide. In developed countries farms tend to become larger, with a concentration of farm operations. Animal farming has been associated with negative respiratory effects such as work-related asthma and rhinitis. However, being born and raised or working on a farm reduces the risk of atopic asthma and rhinitis later in life. A risk of chronic bronchitis and bronchial obstruction/COPD has been reported in confinement buildings and livestock farmers. This position paper reviews the literature linking exposure information to intensive animal farming and the risk of work-related respiratory diseases and focuses on prevention. Animal farming is associated with exposure to organic dust containing allergens and microbial matter including alive microorganisms and viruses, endotoxins and other factors like irritant gases such as ammonia and disinfectants. These exposures have been identified as specific agents/risk factors of asthma, rhinitis, chronic bronchitis, COPD and reduced FEV1. Published studies on dust and endotoxin exposure in livestock farmers do not show a downward trend in exposure over the last 30 years, suggesting that the workforce in these industries is still overexposed and at risk of developing respiratory disease. In cases of occupational asthma and rhinitis, avoidance of further exposure to causal agents is recommended, but it may not be obtainable in agriculture, mainly due to socio-economic considerations. Hence, there is an urgent need for focus on farming exposure in order to protect farmers and others at work in these and related industries from developing respiratory diseases and allergy.

Workplace exposure to wood dust and the prevalence of wood-specific sensitization.

Wood is processed worldwide, and occupational exposure to wood dust is affecting millions of workers. Studies have identified wood dust as a risk factor for non-malignant respiratory diseases consistent with both an allergic and a non-allergic origin. This paper summarizes our current knowledge on the importance of specific sensitization among subjects occupationally exposed to wood dust. Specific sensitization to wood dust exists, but is probably of minor importance for most wood species. In order to move the research field forward increased focus on more standardized tools for specific IgE (sIgE) diagnostics is needed and more specific tools are necessary to identify clinical relevant cases of wood dust sensitization. Moreover epidemiological studies on the occurrence of sIgE-mediated sensitization in different populations of woodworkers are needed.

Zoonotic helminth exposure and risk of allergic diseases: A study of two generations in Norway.

BACKGROUND: Animal and human studies indicate that definitive host helminth infections may confer protection from allergies. However, zoonotic helminths, such as Toxocara species (spp.), have been associated with increased allergies. OBJECTIVE: We describe the prevalence of Toxocara spp. and Ascaris spp. seropositivity and associations with allergic diseases and sensitization, in 2 generations in Bergen, Norway. METHODS: Serum levels of total IgG4, anti-Toxocara spp. IgG4 and Ascaris spp. IgG4 were established by ELISA in 2 cohorts: parents born 1945-1972 (n = 171) and their offspring born 1969-2003 (n = 264). Allergic outcomes and covariates were recorded through interviews and clinical examinations including serum IgEs and skin prick tests. RESULTS: Anti-Ascaris spp. IgG4 was detected in 29.2% of parents and 10.3% of offspring, and anti-Toxocara spp. IgG4 in 17.5% and 8.0% of parents and offspring, respectively. Among offspring, anti-Toxocara spp. IgG4 was associated with pet keeping before age 15 (OR = 6.15; 95% CI = 1.37-27.5) and increasing BMI (1.16[1.06-1.25] per kg/m2 ). Toxocara spp. seropositivity was associated with wheeze (2.97[1.45- 7.76]), hayfever (4.03[1.63-9.95]), eczema (2.89[1.08-7.76]) and cat sensitization (5.65[1.92-16.6]) among offspring, but was not associated with allergic outcomes among parents. Adjustment for childhood or current pet keeping did not alter associations with allergies. Parental Toxocara spp. seropositivity was associated with increased offspring allergies following a sex-specific pattern. CONCLUSIONS & CLINICAL RELEVANCE: Zoonotic helminth exposure in Norway was less frequent in offspring than parents; however, Toxocara spp. seropositivity was associated with increased risk of allergic manifestations in the offspring generation, but not among parents. Changes in response to helminth exposure may provide insights into the increase in allergy incidence in affluent countries.

Maternal hypothyroidism in the perinatal period and childhood asthma in the offspring.

BACKGROUND: There is increasing interest in the possible link between maternal hypothyroidism in the perinatal period and childhood asthma risk. We explored this in this study while accounting for the timing of hypothyroidism diagnosis. Further, we evaluated whether the risk was moderated by thyroid hormone treatment during pregnancy. METHODS: We conducted a population-based cohort study using Danish national registers. All live-born singletons in Denmark from 1998 to 2007 were identified. Maternal hypothyroidism and asthma in the children were defined by data from the Patient Register and Prescription Registry. We estimated incidence rate ratios (IRRs) of asthma among children born to hypothyroid mothers versus children born to mothers with no recorded thyroid dysfunction using Poisson regression models. RESULTS: Of 595 669 children, 3524 children were born to mothers with hypothyroidism diagnosed before delivery and 4664 diagnosed after delivery. Overall, 48 990 children received treatment for asthma. The IRRs of asthma was 1.16 (95% confidence interval (CI): 1.03-1.30) and 1.12 (95% CI: 1.02-1.24) for children born to mothers with hypothyroidism diagnosed before and after delivery, compared to children born to mothers with no thyroid dysfunction. The highest risk was observed among children born to mothers with hypothyroidism diagnosed before delivery who did not receive thyroid hormone treatment during pregnancy (IRR=1.37, 95% CI: 1.04-1.80). CONCLUSION: Our findings suggest that maternal hypothyroidism, especially when it is untreated, increases childhood asthma risk. Early detection and appropriate treatment of hypothyroidism in pregnant women may be an area for possible prevention of childhood asthma.

Prenatal antibiotics and atopic dermatitis among 18-month-old children in the Danish National Birth Cohort.

BACKGROUND: Despite extensive research, the aetiology of atopic dermatitis remains largely unknown, but reduced intestinal microbiota diversity in neonates has been linked to subsequent atopic dermatitis. Consequently, postnatal antibiotics have been proposed as a risk factor, but a potential association between prenatal antibiotics and atopic dermatitis is not well studied. Overall, the current evidence suggests a positive association between exposure to prenatal antibiotics and atopic dermatitis. OBJECTIVE: To investigate the association between prenatal antibiotics and atopic dermatitis among 18-month-old children. METHODS: This study conducted within the Danish National Birth Cohort included 62 560 mother-child pairs. Data on maternal prenatal antibiotics were collected in the 30th gestation week and 6 months post-partum, and offspring atopic dermatitis 18 months post-partum through telephone interviews. Antibiotic use was categorized by the timing of exposure as 1st-2nd trimester (gestation week 0-29), 3rd trimester (gestation week 30-birth), all three trimesters or none. Data were analysed by logistic regression analyses adjusting for potential confounders. RESULTS: Exposure to antibiotics prenatally was associated with increased odds of atopic dermatitis among children born by atopic mothers but only when used in both 1st-2nd and 3rd trimester (ORadj 1.45, 95% CI: 1.19-1.76). The findings were consistent using different definitions of atopic dermatitis. CONCLUSIONS AND CLINICAL RELEVANCE: Prenatal exposure to antibiotics throughout pregnancy was associated with an increased risk of atopic dermatitis but only within the first 18 months of life among children born by atopic mothers. The clinical usefulness of this finding must rest on corroboration in independent data sources.

Clinical markers of asthma and IgE assessed in parents before conception predict asthma and hayfever in the offspring.

BACKGROUND: Mice models suggest epigenetic inheritance induced by parental allergic disease activity. However, we know little of how parental disease activity before conception influences offspring's asthma and allergy in humans. OBJECTIVE: We aimed to assess the associations of parental asthma severity, bronchial hyperresponsiveness (BHR), and total and specific IgEs, measured before conception vs. after birth, with offspring asthma and hayfever. METHODS: The study included 4293 participants (mean age 34, 47% men) from the European Community Respiratory Health Survey (ECRHS) with information on asthma symptom severity, BHR, total and specific IgEs from 1991 to 1993, and data on 9100 offspring born 1972-2012. Adjusted relative risk ratios (aRRR) for associations of parental clinical outcome with offspring allergic disease were estimated with multinomial logistic regressions. RESULTS: Offspring asthma with hayfever was more strongly associated with parental BHR and specific IgE measured before conception than after birth [BHR: aRRR = 2.96 (95% CI: 1.92, 4.57) and 1.40 (1.03, 1.91), respectively; specific IgEs: 3.08 (2.13, 4.45) and 1.83 (1.45, 2.31), respectively]. This was confirmed in a sensitivity analysis of a subgroup of offspring aged 11-22 years with information on parental disease activity both before and after birth. CONCLUSION & CLINICAL RELEVANCE: Parental BHR and specific IgE were associated with offspring asthma and hayfever, with the strongest associations observed with clinical assessment before conception as compared to after birth of the child. If the hypothesis is confirmed in other studies, parental disease activity assessed before conception may prove useful for identifying children at risk for developing asthma with hayfever.

Building dampness and mold in European homes in relation to climate, building characteristics and socio-economic status: The European Community Respiratory Health Survey ECRHS II.

We studied dampness and mold in homes in relation to climate, building characteristics and socio-economic status (SES) across Europe, for 7127 homes in 22 centers. A subsample of 3118 homes was inspected. Multilevel analysis was applied, including age, gender, center, SES, climate, and building factors. Self-reported water damage (10%), damp spots (21%), and mold (16%) in past year were similar as observed data (19% dampness and 14% mold). Ambient temperature was associated with self-reported water damage (OR=1.63 per 10°C; 95% CI 1.02-2.63), damp spots (OR=2.95; 95% CI 1.98-4.39), and mold (OR=2.28; 95% CI 1.04-4.67). Precipitation was associated with water damage (OR=1.12 per 100 mm; 95% CI 1.02-1.23) and damp spots (OR=1.11; 95% CI 1.02-1.20). Ambient relative air humidity was not associated with indoor dampness and mold. Older buildings had more dampness and mold (P<.001). Manual workers reported less water damage (OR=0.69; 95% CI 0.53-0.89) but more mold (OR=1.27; 95% CI 1.03-1.55) as compared to managerial/professional workers. There were correlations between reported and observed data at center level (Spearman rho 0.61 for dampness and 0.73 for mold). In conclusion, high ambient temperature and precipitation and high building age can be risk factors for dampness and mold in homes in Europe.

The effects of growing up on a farm on adult lung function and allergic phenotypes: an international population-based study.

RATIONALE: Evidence has suggested that exposure to environmental or microbial biodiversity in early life may impact subsequent lung function and allergic disease risk. OBJECTIVES: To investigate the influence of childhood living environment and biodiversity indicators on atopy, asthma and lung function in adulthood. METHODS AND MEASUREMENTS: The European Community Respiratory Health Survey II investigated ∼10 201 participants aged 26-54 years from 14 countries, including participants' place of upbringing (farm, rural environment or inner city) before age 5 years. A 'biodiversity score' was created based on childhood exposure to cats, dogs, day care, bedroom sharing and older siblings. Associations with lung function, bronchial hyper-responsiveness (BHR), allergic sensitisation, asthma and rhinitis were analysed. MAIN RESULTS: As compared with a city upbringing, those with early-life farm exposure had less atopic sensitisation (adjusted OR 0.46, 95% CI 0.37 to 0.58), atopic BHR (0.54 (0.35 to 0.83)), atopic asthma (0.47 (0.28 to 0.81)) and atopic rhinitis (0.43 (0.32 to 0.57)), but not non-atopic outcomes. Less pronounced protective effects were observed for rural environment exposures. Women with a farm upbringing had higher FEV1 (adjusted difference 110 mL (64 to 157)), independent of sensitisation and asthma. In an inner city environment, a higher biodiversity score was related to less allergic sensitisation. CONCLUSIONS: This is the first study to report beneficial effects of growing up on a farm on adult FEV1. Our study confirmed the beneficial effects of early farm life on sensitisation, asthma and rhinitis, and found a similar association for BHR. In persons with an urban upbringing, a higher biodiversity score predicted less allergic sensitisation, but to a lesser magnitude than a childhood farm environment.

Prenatal exposure to maternal bereavement and offspring psoriasis: a Danish nationwide cohort study.

BACKGROUND: Prenatal stress may alter immune competence of the fetus. Limited data exist on the role of antenatal stress in psoriasis development. OBJECTIVES: To investigate whether prenatal exposure to maternal bereavement increases the risk of offspring psoriasis. METHODS: This register-based cohort study included 1 811 917 live singletons born from 1978 to 2008 in Denmark. The children were assigned to the bereaved group if their mothers lost a child, partner/spouse, parent or sibling during pregnancy or up to 12 months before pregnancy. Follow-up started at the date of birth and ended at the date of first hospital treatment for psoriasis or a prescription redeemed for topical vitamin D derivatives (often used to treat psoriasis), emigration, death or 31 December 2010, whichever came first. We evaluated the hazard ratio (HR) of psoriasis in bereaved children using Cox proportional hazards regressions, compared with the nonbereaved group. RESULTS: During 28 million person-years of follow-up, 7956 children were hospitalized or prescribed medications for psoriasis. By the age of 30 years, 1·54% [95% confidence interval (CI) 1·25-1·90%] of children from the bereaved group were diagnosed with psoriasis, compared with 1·34% (95% CI 1·30-1·38%) of nonbereaved children. Overall, prenatal exposure to maternal bereavement was not associated with risk of psoriasis in general (HR 1·05, 95% CI 0·91-1·20). However, children born to mothers who lost a partner/spouse or an older child had an increased risk of psoriasis (HR 1·33, 95% CI 1·02-1·73). CONCLUSIONS: Prenatal exposure to the most stressful life event may contribute to the development and/or exacerbation of psoriasis.

Method for a homogeneous distribution of pollens in an environmental exposure chamber.

BACKGROUND: A variety of different environmental exposure chambers (EECs) have been used to evaluate treatments for allergic rhinitis. OBJECTIVE: To describe and test a system for a homogenous distribution of grass pollen, Phleum Pratense, in an EEC to be used for controlled pollen exposure studies in allergic participants. METHODS: A chamber made of stainless steel with completely rounded corners, seating four individuals at a time, was used. Room pressure, temperature, humidity and the air change rate were kept constant throughout the study period. A rotating pipette dispensed a uniform supply of pollen into a turntable's v-shaped grooves. A stainless steel capillary tube sucked the pollens into a venturi throat at which time the pollens were mixed with a high-pressure airstream of compressed high-efficiency particulate arrestance filtered air and then transported to a spreading plate inside the EEC. To achieve uniform concentrations in the EEC, the turntable's rotating speed was continuously adjusted using information from video-coupled feedback and feed forward mechanisms. Pollen levels were detected using standard volumetric air samplers and laser particle counters. The target pollen exposure level was 1000 pollens/m(3) . Twenty-one participants were exposed to pollens in the EEC twice for 210 min. Participants evaluated their symptoms every 30 min using a total nasal symptom score (TNSS) consisting of blocked nose, runny nose, nasal itching and sneezing. RESULTS: Across fifteen study days, the average pollen level was 982 pollens/m(3) (SD, 102 pollens/m(3) ). On average, participants experienced a 10% difference in overall pollen levels between their two visits to the EEC. The mean TNSSs rose throughout the exposure period, with a low at baseline of 0.43 (SD, 0.68) to a high of 4.71 (SD, 2.43) just before exiting the EEC. CONCLUSION AND CLINICAL RELEVANCE: This EEC provides a reproducible, precise and homogenous distribution of pollens making it suitable for single-centre allergy clinical trials.

The risk of respiratory symptoms on allergen exposure increases with increasing specific IgE levels.

BACKGROUND: The relation between IgE sensitization and allergic respiratory symptoms has usually been evaluated by dichotomizing specific IgE levels. The aim of this study was to evaluate the association between specific IgE levels and risk of symptoms on allergen-related exposure, with special reference to allergen-related asthma-rhinitis comorbidity. METHODS: We considered 6391 subjects enrolled within the European Community Respiratory Health Survey 2, having information on cat/grass/D. pteronyssinus IgE levels and symptoms on exposure to animals/pollen/dust. The risk of oculonasal/asthmalike/both symptoms was evaluated by a multinomial logistic model. RESULTS: A clear positive association was observed between specific IgE levels to cat/grass/mite and the risk of symptoms on each allergen-related exposure (test for trend with P < 0.001). This trend was particularly pronounced when considering the coexistence of asthmalike and oculonasal symptoms. Compared to non-sensitized subjects, subjects with specific IgE to cat >= 3.5 kU/l presented relative risk ratios of 11.4 (95% CI 6.7-19.2), 18.8 (8.2-42.8), and 55.3 (30.5-100.2) when considering, respectively, only oculonasal symptoms, only asthmalike symptoms, or both. A similar pattern was observed when considering specific IgE to grass/mite and symptoms on exposure to pollen/dust. Also the proportion of people using inhaled medicines or visiting a general practitioner for breathing problems in the previous year increased with increasing sum of specific IgE to cat/grass/mite. CONCLUSION: Specific IgE level is the most important predictor of allergen-related symptoms. The risk of both oculonasal/asthmalike symptoms increases with specific IgE levels, suggesting that specific IgE contributes to the 'united airways disease'.

Prenatal maternal stress and atopic diseases in the child: a systematic review of observational human studies.

BACKGROUND: A growing number of studies suggest that maternal stress during pregnancy promotes atopic disorders in the offspring. This is the first systematic review to address prenatal maternal stress (PNMS) and the subsequent risk of atopy-related outcomes in the child. METHODS: The review was performed in accordance to the PRISMA criteria. We searched and selected studies in PubMed, Scopus, Embase and PsychINFO until November 2014. RESULTS: Sixteen (with 25 analyses) of 426 identified articles met the review criteria. Five main PNMS exposures (negative life events, anxiety/depression, bereavement, distress and job strain) and five main atopic outcomes (asthma, wheeze, atopic dermatitis, allergic rhinitis and IgE) were assessed across the studies. Overall, 21 of the 25 analyses suggested a positive association between PNMS and atopic outcomes. Of the 11 exposure-response analyses reported, six found statistically significant trends. CONCLUSION: This systematic review suggests a relationship between maternal stress during pregnancy and atopic disorders in the child. However, the existing studies are of diverse quality. The wide definitions of often self-reported stress exposures imply a substantial risk for information bias and false-positive results. Research comparing objective and subjective measures of PNMS exposure as well as objective measures for atopic outcome is needed.

The Danish urban-rural gradient of allergic sensitization and disease in adults.

BACKGROUND: The reported prevalence of allergic sensitization among children is lower in rural areas than in urban areas of the world. The aim was to investigate the urban-rural differences of allergic sensitization to inhalant allergens in adults depending on childhood exposure living in an industrialized country as Denmark. METHODS: A total of 1236 male participants of 30-40 years of age recruited from two epidemiological studies were divided into four groups with regard to place of upbringing; city, town, rural area and farm. Allergic sensitization was assessed by skin prick tests (SPTs) to 10 inhalant allergens and measurements of serum specific IgE (sIgE) to four inhalant allergens (grass, birch, cat and house dust mite). RESULTS: The prevalence of allergic sensitization to inhalant allergens decreased with decreasing degree of urbanized childhood. The risk of being sensitized to one or more allergens also decreased with decreasing degree of urbanized upbringing measured by sIgE to 4 common allergens as odds ratio with 95% confidence intervals with city as reference; town 0.60 (0.39-0.92), rural area 0.34 (0.22-0.52) and farm 0.31 (0.21-0.46). Furthermore, it was measured by SPT to 10 common allergens; town 0.52 (0.33-0.84), rural area 0.34 (0.21-0.53) and farm 0.29 (0.19-0.45). This urban-rural association was also seen for the risk of sensitization to specific allergens, rhinitis and allergic asthma. CONCLUSION: This is the first study to show an urban-rural gradient of overall allergic sensitization and specific allergen sensitization in adults depending on their childhood exposure. In this highly homogenous western population, exposure to a less urbanized childhood was associated with lower risk of allergic sensitization and disease as an adult.

Exposure levels, determinants and IgE mediated sensitization to bovine allergens among Danish farmers and non-farmers.

BACKGROUND: Bovine allergens can induce allergic airway diseases. High levels of allergens in dust from stables and homes of dairy farmers have been reported, but sparse knowledge about determinants for bovine allergen levels and associations between exposure level and sensitization is available. OBJECTIVE: To investigate levels and determinants of bovine allergen exposure among dairy, pig and mink farmers (bedroom and stable), and among former and never farmers (bedroom), and to assess the prevalence of bovine allergen sensitization in these groups. METHODS: In 2007-2008, 410 settled dust samples were collected in stables and in bedrooms using an electrostatic dust-fall collector over a 14 day period among 54 pig farmers, 27 dairy farmers, 3 mink farmers as well as 71 former and 48 never farmers in Denmark. For farmers sampling was carried out both during summer and winter. Bovine allergen levels (µg/m(2)) were measured using a sandwich ELISA. Determinants for bovine allergen exposure in stables and bedrooms were explored with mixed effect regression analyses. Skin prick test with bovine allergen was performed on 48 pig farmers, 20 dairy farmers, 54 former and 31 never farmers. RESULTS: Bovine allergen levels varied by five orders of magnitude, as expected with substantially higher levels in stables than bedrooms, especially for dairy farmers. Bovine allergen levels in bedrooms were more than one order of magnitude higher for dairy farmers compared to pig farmers. Former and never farmers had low levels of bovine allergens in their bedroom. Bovine allergen levels during summer appeared to be somewhat higher than during winter. Increased bovine allergen levels in the bedroom were associated with being a farmer or living on a farm. Mechanical ventilation in the bedroom decreased bovine allergen level, significant for dairy farmers ß=-1.4, p<0.04. No other significant effects of either sampling or residence characteristics were seen. Allergen levels in dairy stables were associated to type of dairy stable, but not to other stable or sampling characteristics. Sensitization to bovine allergens was only found in one pig farmer. CONCLUSION: This study confirms high bovine allergen levels in dairy farms, but also suggests sensitization to bovine allergens among Danish farmers to be uncommon. Furthermore the importance of a carrier home effect on allergen load is emphasized. Whether the risk for bovine sensitization is related to the allergen level in the stable or the dwelling remains to be determined.

The prevalence of byssinosis among cotton workers in the north of Benin.

BACKGROUND: Cotton is the main agricultural export product in Benin. Cotton dust is thus present in the air during the handling and processing of cotton. This dust contains a mixture of substances including ground up plant matter, fibres, bacteria, fungi, soil, pesticides, noncotton matter, and other contaminants. While cotton processing is decreasing in industrialized countries, it is increasing in developing countries. Cotton processing, particularly in the early processes of spinning, can cause byssinosis. OBJECTIVE: To determine the respiratory effects of cotton dust exposure among cotton mill workers in Benin. METHODS: In a cross-sectional study, 109 workers exposed to cotton dust and 107 unexposed workers were studied. The International Commission on Occupational Health (ICOH) questionnaire was used for data collection on respiratory symptoms. For each worker, crossshift pulmonary function was performed with a dry spirometer. Based on the severity of respiratory symptoms and spirometry byssinosis was defined and classified according to the criteria of Schilling, et al. RESULTS: The mean ± SD age of the exposed and unexposed workers was 46.3 ± 7.8 and 37.0 ± 8.3 years, respectively (p<0.001). The mean FEV1 predicted value for the exposed and unexposed workers was 76.3% and 77.3%, respectively. The prevalence of grade 3 byssinosis was 21.1% (95% CI: 13.4-28.9) in exposed workers and 8.4% (95% CI: 3.1-13.7) in unexposed workers (p=0.006). On Mondays, the exposed workers had more respiratory symptoms than unexposed workers; for grade 3 byssinosis, the prevalence was 13.8% in exposed and 4.7% in unexposed workers (p=0.011). CONCLUSION: The prevalence of respiratory symptoms and byssinosis among cotton mill workers in Benin is high and needs prompt attention of health care workers and policymakers.

Monitoring of occupational and environmental aeroallergens-- EAACI Position Paper. Concerted action of the EAACI IG Occupational Allergy and Aerobiology & Air Pollution.

Exposure to high molecular weight sensitizers of biological origin is an important risk factor for the development of asthma and rhinitis. Most of the causal allergens have been defined based on their reactivity with IgE antibodies, and in many cases, the molecular structure and function of the allergens have been established. Significant information on allergen levels that cause sensitization and allergic symptoms for several major environmental and occupational allergens has been reported. Monitoring of high molecular weight allergens and allergen carrier particles is an important part of the management of allergic respiratory diseases and requires standardized allergen assessment methods for occupational and environmental (indoor and outdoor) allergen exposure. The aim of this EAACI task force was to review the essential points for monitoring environmental and occupational allergen exposure including sampling strategies and methods, processing of dust samples, allergen analysis, and quantification. The paper includes a summary of different methods for sampling and allergen quantification, as well as their pros and cons for various exposure settings. Recommendations are being made for different exposure scenarios.

EAACI position paper: irritant-induced asthma.

The term irritant-induced (occupational) asthma (IIA) has been used to denote various clinical forms of asthma related to irritant exposure at work. The causal relationship between irritant exposure(s) and the development of asthma can be substantiated by the temporal association between the onset of asthma symptoms and a single or multiple high-level exposure(s) to irritants, whereas this relationship can only be inferred from epidemiological data for workers chronically exposed to moderate levels of irritants. Accordingly, the following clinical phenotypes should be distinguished within the wide spectrum of irritant-related asthma: (i) definite IIA, that is acute-onset IIA characterized by the rapid onset of asthma within a few hours after a single exposure to very high levels of irritant substances; (ii) probable IIA, that is asthma that develops in workers with multiple symptomatic high-level exposures to irritants; and (iii) possible IIA, that is asthma occurring with a delayed-onset after chronic exposure to moderate levels of irritants. This document prepared by a panel of experts summarizes our current knowledge on the diagnostic approach, epidemiology, pathophysiology, and management of the various phenotypes of IIA.

Guidelines for the management of work-related asthma.

Work-related asthma, which includes occupational asthma and work-aggravated asthma, has become one of the most prevalent occupational lung diseases. These guidelines aim to upgrade occupational health standards, contribute importantly to transnational legal harmonisation and reduce the high socio-economic burden caused by this disorder. A systematic literature search related to five key questions was performed: diagnostics; risk factors; outcome of management options; medical screening and surveillance; controlling exposure for primary prevention. Each of the 1,329 retrieved papers was reviewed by two experts, followed by Scottish Intercollegiate Guidelines Network grading, and formulation of statements graded according to the Royal College of General Practitioners' three-star system. Recommendations were made on the basis of the evidence-based statements, which comprise the following major evidence-based strategic points. 1) A comprehensive diagnostic approach considering the individual specific aspects is recommended. 2) Early recognition and diagnosis is necessary for timely and appropriate preventative measures. 3) A stratified medical screening strategy and surveillance programme should be applied to at-risk workers. 4) Whenever possible, removing exposure to the causative agent should be achieved, as it leads to the best health outcome. If this is not possible, reduction is the second best option, whereas respirators are of limited value. 5) Exposure elimination should be the preferred primary prevention approach.

Incidence and prevalence of chronic bronchitis: impact of smoking and welding. The RHINE study.

OBJECTIVE: To investigate the prevalence and incidence rate of chronic bronchitis (CB) in relation to smoking habits and exposure to welding fumes in a general population sample. METHODS: Subjects from Northern Europe born between 1945 and 1971 who participated in Stage 1 (1989-1994) of the European Community Respiratory Health Survey were mailed a respiratory questionnaire in 1999-2001 (the RHINE study); 15,909 answered the questionnaire and gave complete data on smoking. CB was defined as chronic productive cough of at least 3 months a year for 2 consecutive years. The questionnaire comprised an item about age when CB started and items about exposure to welding fumes. The incidence of CB was retrospectively assessed for the observation period 1980-2001. RESULTS: CB had a prevalence of 5.4%, and was associated with current smoking and welding exposure. The incidence rate of CB was 1.9 per 1000 person-years, and was increased in relation to welding exposure (low exposure HR 1.4, 95%CI 1.1-1.8; high exposure HR 2.0, 95%CI 1.6-2.7) and in relation to smoking (HR 2.1, 95%CI 1.8-2.5). CONCLUSION: Smoking and occupational exposure to welding fumes are both associated with an increased risk of CB.

Impact of cross-reactive carbohydrate determinants on wood dust sensitization.

BACKGROUND: Occupational wood dust exposure can induce allergy and may be one cause of respiratory health problems among woodworkers. OBJECTIVE: The objective was to determine the prevalence and quantitative level of specific immunoglobulin E (sIgE) to beech and pine wood in exposed workers. Wood sensitization was specified with regard to cross-reactivity and was correlated to the reported symptoms. METHODS: Danish workers (n=701) were investigated for sIgE to beech and pine. Wood samples from workplaces were analysed and coupled to ImmunoCAPs. Workers sensitized to wood were tested for cross-reactive carbohydrate determinants (CCDs) and environmental allergens. IgE binding was specified for glycogenic vs. proteinogenic epitopes by inhibition tests. RESULTS: The prevalence of wood sensitization among all workers was 3.7%. There was no association between sensitization prevalence or sIgE concentrations and self-reported allergic symptoms. Beech- and pine-sensitized workers showed a high prevalence of CCD sensitization (73%). However, workers with a single sensitization to wood had no sIgE to CCDs. Specifying IgE epitopes demonstrated that sera of workers reporting allergic symptoms recognized proteinogenic IgE-epitopes on wood allergens, whereas workers without allergic symptoms had primarily sIgE-epitopes to glycogenic structures. Although 96% of the wood-sensitized workers were atopic, no significant correlation was found between wood sensitization and sIgE to beech and birch pollen, but an association was found between sIgE against CCDs and pine pollen. CONCLUSION: Sensitization prevalence to beech and pine wood measured by tailored ImmunoCAPs was not correlated to allergic symptoms. We recommend the application of CCD tools to assess the relevance of individual wood sensitization.