ABSTRACT
UNLABELLED: OBJECTIVES To investigate exposures, respiratory symptoms, lung function and exposure-response relationships among aluminium cast-house workers. METHODS: A cross-sectional study was conducted among 182 workers. Exposure data were used to model exposure to irritants. Lung function and questionnaire data on respiratory symptoms were compared to a general population sample and an internal reference group. Blood samples were taken from 156 workers to examine total IgE, eosinophils and sensitisation to common allergens. RESULTS: Average daily mean exposure to inhalable dust, metals, hydrogen fluoride, fluoride salts and sulphur dioxide was relatively low compared to reference values. Airflow patterns in the hall were disturbed regularly and resulted in pot emissions with high concentrations of fluorides. Peak exposures to chlorine gas occurred intermittently due to production process disturbances. Workers reported significantly more respiratory symptoms (continuous trouble with breathing (prevalence ratio (PR) 2.5; 95% CI 1.2 to 5.3), repeated trouble with breathing (PR 1.8; 95% CI 1.1 to 3.0), wheezing (PR 1.4; 95% CI 1.1 to 1.8), asthma attack (ever) (PR 2.8; 95% CI 1.7 to 4.6) and doctor diagnosed asthma (PR 2.6; 95% CI 1.5 to 4.4). Regression analysis showed significantly lower FEV(1) values (-195 ml) and FVC values (-142 ml) compared to a general population sample. Lung function did not differ between groups. CONCLUSION: This epidemiological study suggests cast-house workers in the aluminium industry are exposed to respiratory hazards. Exposure-response relationships could not be demonstrated but this study supports preventive measures in the work environment with a focus on (peak) exposures to irritants.
Subject(s)
Air Pollutants, Occupational/toxicity , Aluminum/toxicity , Asthma/epidemiology , Cough/epidemiology , Occupational Diseases/epidemiology , Occupational Exposure/adverse effects , Adult , Aged , Asthma/chemically induced , Cough/chemically induced , Cross-Sectional Studies , Dust/analysis , Forced Expiratory Volume/physiology , Humans , Industry , Male , Middle Aged , Netherlands/epidemiology , Occupational Diseases/chemically induced , Respiratory Sounds , Risk Factors , Spirometry , Vital Capacity/physiologyABSTRACT
OBJECTIVES: To investigate sensitisation and respiratory health among workers who produce liquid detergent products and handle liquid detergent enzymes. METHODS: We performed a cross-sectional study among 109 eligible workers of a detergent products plant. 108 were interviewed for respiratory and allergic symptoms and 106 blood samples were taken from them to examine sensitisation to enzymes. Those sensitised to > or = 1 enzymes were referred for clinical evaluation. Workers and representatives were interviewed to characterise exposure qualitatively and estimate exposure semi-quantitatively. Workers were classified into three exposure groups with varying exposure profiles to enzymes, based on frequency, duration, and level of exposure. RESULTS: Workers were exposed to proteases, alpha-amylase, lipase and cellulase. The highest exposures occurred in the mixing area. Liquid spills with concentrated enzyme preparations and leakage of enzymes during weighing, transportation and filling were causing workplace contaminations and subsequently leading to both dermal and inhalation exposure for workers. Workers with the highest exposures reported significantly more work-related symptoms of itching nose (prevalence ratio (PR) = 4.2, 95% CI 1.5 to 12.0) and sneezing (PR = 4.0, 95% CI 1.5 to 10.8) and marginally significant more symptoms of wheezing (PR = 2.9, 95% CI 0.9 to 8.7) compared with the least exposed group. Fifteen workers (14.2%) were sensitised to > or = 1 enzymes. A marginally statistically significant gradient in sensitisation across the exposure categories was found (p = 0.09). There was a clinical case of occupational asthma and two others with probable occupational rhinitis. CONCLUSIONS: Workers exposed to liquid detergent enzymes are at risk of developing sensitisation (14%) and respiratory allergy.
Subject(s)
Detergents/toxicity , Enzymes/toxicity , Occupational Diseases/chemically induced , Respiratory Hypersensitivity/chemically induced , Adult , Asthma/chemically induced , Detergents/chemistry , Dust/analysis , Environmental Monitoring/methods , Enzymes/analysis , Epidemiologic Methods , Epidemiological Monitoring , Female , Humans , Immunoglobulin E/blood , Male , Middle Aged , Occupational Exposure/adverse effects , Occupational Exposure/analysis , Solutions , Young AdultABSTRACT
OBJECTIVES: Four diacetyl workers were found to have bronchiolitis obliterans syndrome. Exposures, respiratory symptoms, lung function and exposure-response relationships were investigated. METHODS: 175 workers from a plant producing diacetyl between 1960 and 2003 were investigated. Exposure data were used to model diacetyl exposure. Lung function and questionnaire data on respiratory symptoms were compared to a general population sample and respiratory symptoms to an internal reference group. RESULTS: Workers were potentially exposed to acetoin, diacetyl, acetaldehyde and acetic acid. Historic diacetyl exposure ranged from 1.8 to 351 mg/m(3), and from 3 to 396 mg/m(3) for specific tasks. Diacetyl workers reported significantly more respiratory symptoms compared to the general population sample (continuous trouble with breathing (prevalence ratio (PR) = 2.6; 95% CI 1.3 to 5.1), daily cough (PR = 1.5; 95% CI 1.1 to 2.1), asthma attack (ever) (PR = 2.0; 95% CI 1.2 to 3.4), doctor diagnosed asthma (PR = 2.2; 95% CI 1.3 to 3.8) and asthma attack in the last year (PR = 4.7; 95% CI 1.9 to 11.4)) and to a minimally exposed internal reference group (ever trouble with breathing (PR = 2.8; 95% CI 1.1 to 7.0) and work-related shortness of breath in the last year (PR = 7.5; 95% CI 1.1 to 52.9)). Lung function did not differ between groups. A positive relationship between exposure and FEV(1) was found. CONCLUSION: The excess of respiratory symptoms in this retrospective cohort suggests that diacetyl production poses an occupational hazard. Limited historical exposure data did not support a quantitative individual diacetyl exposure-response relationship, but our findings suggest that preventive measures are prudent.
Subject(s)
Air Pollutants, Occupational/adverse effects , Diacetyl/toxicity , Flavoring Agents/toxicity , Occupational Diseases/chemically induced , Respiration Disorders/chemically induced , Adult , Air Pollutants, Occupational/analysis , Bronchiolitis Obliterans/chemically induced , Chemical Industry , Cross-Sectional Studies , Diacetyl/analysis , Environmental Monitoring/methods , Flavoring Agents/analysis , Forced Expiratory Volume/drug effects , Humans , Male , Middle Aged , Occupational Exposure/adverse effects , Occupational Exposure/analysis , Spirometry , Vital Capacity/drug effectsABSTRACT
OBJECTIVES: It was hypothesised that inflammation plays a dominant part in the respiratory effects of exposure to wood dust. The purpose of this study was to relate the nasal inflammatory responses of workers exposed to meranti wood dust to (a) levels of exposure, (b) respiratory symptoms and (c) respiratory function. METHODS: A cross sectional study was carried out in 1997 in a woodworking plant that used mainly meranti, among 982 workers exposed to different concentrations of wood dust. Personal sampling (n=243) of inhalable dust measurements indicated mean exposure in specific jobs, and enabled classification of 930 workers in three exposure classes (<2, 2-5, and >5 mg/m(3)) based on job title. Questionnaires were used to screen respiratory symptoms in the entire population. Lung function was measured with two different techniques, conventional flow-volume curves and the forced oscillation technique. Nasal lavage was done to assess inflammation in the upper respiratory tract. RESULTS: A negative trend between years of employment and most flow-volume variables was found in men, but not in women workers. Current exposure, however, was not related to spirometric outcomes, respiratory symptoms, or nasal cellularity. Some impedance variables were related to current exposure but also with better function at higher exposure. CONCLUSIONS: Exposure to meranti wood dust did not cause an inflammation in the upper respiratory tract nor an increase of respiratory symptoms or decrease of lung function. These data do not corroborate the hypothesis that inflammation plays a part in airway obstruction induced by wood dust.
Subject(s)
Dust/adverse effects , Lung/physiology , Nasal Mucosa/immunology , Occupational Exposure/adverse effects , Wood , Adult , Analysis of Variance , Cross-Sectional Studies , Female , Humans , Indonesia , Male , Respiratory Function Tests , Smoking/adverse effectsABSTRACT
OBJECTIVE: Quantitative risk assessments have been made for wheat dust and allergen exposure and wheat sensitization using classical epidemiological approaches based on simple categorizations in exposure groups. Such analyses suggest the existence of an exposure threshold level for wheat specific sensitization and were used as input in recently conducted risk assessments for wheat flour by the American Conference of Governmental Industrial Hygienists and the Dutch Expert Committee on Occupational Standards. More advanced statistical analyses were applied using generalized additive modeling and smoothed plots to evaluate the shape of the exposure response relationship in greater detail and evaluate the presence of exposure thresholds. METHODS: Data were used from a recently conducted epidemiological study in bakery workers. Information was available on wheat sensitization (IgE antibodies), inhalable dust levels and wheat allergen levels. Initial analyses were based on simple exposure categorizations for inhalable dust and allergen exposure. A more detailed analysis using non-parametric generalized additive models (GAM models) and smoothing plots allowed inspection of the presence of an exposure threshold of evaluation of 'no' or 'lowest observed effect levels' (NOELs, LOELs) using exposure data on the individual level. RESULTS: All analyses showed an increasing sensitization risk with increasing exposure. The classical epidemiological analyses gave evidence for the existence of an exposure threshold or 'no observed effect level (NOEL)' for specific wheat sensitization between 0.5 and 1 mg/m3 of inhalable dust. The more advanced analyses did not suggest any evidence for the existence of an exposure threshold. However, estimates of a LOEL obtained by considering an arbitrary increase in sensitization risk between 1.5 and 2 as undesirable, were close to the NOEL from the classical analyses and would therefore not lead to an essentially different exposure limit. The criterion of an increase in wheat sensitization risk was based on the risk in non-wheat dust exposed populations. CONCLUSION: Exposure response modeling using different classical epidemiological approaches and advanced statistical methods resulted in health based LOEL or NOEL estimates within a relatively close range. But when sensitization accompanied by asthma or rhinitis symptoms was considered as critical endpoint, steeper exposure-response relationships were observed which would lead to lower LOEL values.
Subject(s)
Flour/adverse effects , Hypersensitivity/prevention & control , Occupational Exposure/statistics & numerical data , Triticum/adverse effects , Adolescent , Adult , Flour/analysis , Humans , Hypersensitivity/epidemiology , Hypersensitivity/etiology , Immunoglobulin E/blood , Middle Aged , Multivariate Analysis , Netherlands , Occupational Exposure/analysis , Occupational Exposure/prevention & control , Prevalence , Proportional Hazards Models , Risk AssessmentABSTRACT
The purposes of this study were (a) to compare wheat antigen content of inhalable bakery dust in Canada and the Netherlands and, (b) to evaluate the validity of dust exposure measurement as a surrogate of specific antigen exposure. Wheat antigen exposure data from the studies of Canadian and Dutch bakeries were used to explore the correlation between dust and antigen levels, and identify factors explaining variability of the antigen content of bakery dust. Direct comparison and pooling of the data were possible because the same antigen assay was used in both studies. Wheat antigen exposure samples totaling 544 were available, all originating from personal full-shift monitoring of bakery workers. The wheat antigen content of bakery dust varied greatly between the two studies and with different products within each study. Bakery dust from the Canadian study had a much higher wheat antigen content. Therefore, the interstudy difference in the wheat antigen content of bakery dust was by far the most significant in undermining the validity of the use of dust levels as a surrogate measures of wheat antigen exposure. The production of croissants, wheat bread and buns, puff pastry, bagels, and cinnamon buns was associated with increased wheat antigen content of bakery dust, while in rye bread production, bakery dust with less wheat antigen content was emitted. Although we can, in part, account for the pattern of variability in the wheat antigen content of bakery dust (explaining 49% of it), we concluded that the effort involved in modeling it accurately would probably exceed that expended in direct measurement of the antigen level. Therefore, for the exposure assessments carried out for the purpose of managing occupational risks of aeroallergen exposure in bakeries, we recommend the use of analytical techniques that can directly measure antigen exposure.
Subject(s)
Cooking , Dust/analysis , Flour/analysis , Occupational Exposure/analysis , Triticum/immunology , Antigens/analysis , Canada , Humans , Netherlands , Regression Analysis , Reproducibility of ResultsABSTRACT
A cross-sectional study was conducted among 393 workers from 21 bakeries to study the relationship between wheat allergen exposure and wheat sensitization and work-related allergic symptoms. Exposure to wheat allergens was characterized by a recently developed and validated immunoassay. Specific IgE antibodies against wheat flour and common allergens were measured by immunoassays, and work-related allergic symptoms were registered by questionnaire. A strong and positive association was found between wheat flour allergen exposure and wheat flour sensitization. This relationship was steepest and strongest in atopics. Prevalence ratios for high and medium wheat allergen exposure were 5.2 (95% confidence interval [CI], 1.6-16.2), and 2.7 (0.5-14.5) for atopic workers, and 2.5 (0.8-7.5) and 1.4 (0. 3-6.4) for nonatopics, compared with workers with low wheat allergen exposure. In sensitized bakers those with an elevated allergen exposure had more often work-related symptoms, with prevalence ratios for high and medium wheat allergen exposure of 3.5 (CI 1.6-7. 5) and 2.6 (CI 0.9-7.8), respectively, compared with workers with low wheat allergen exposure. The existence of exposure-sensitization gradients suggests that work-related sensitization risk will be negligible when exposure levels will be reduced to average exposure concentration of 0.2 microgram/m3 wheat allergen or approximately 0.5 mg/m3 inhalable dust during a work shift.
Subject(s)
Allergens/adverse effects , Cooking , Flour/adverse effects , Occupational Diseases/prevention & control , Respiratory Hypersensitivity/prevention & control , Triticum/adverse effects , Adult , Antibodies/analysis , Confidence Intervals , Cross-Sectional Studies , Dust/adverse effects , Female , Humans , Hypersensitivity, Immediate/epidemiology , Hypersensitivity, Immediate/immunology , Immunization , Immunoassay , Immunoglobulin E/analysis , Male , Netherlands/epidemiology , Occupational Diseases/epidemiology , Occupational Diseases/immunology , Occupational Exposure , Prevalence , Respiratory Hypersensitivity/epidemiology , Respiratory Hypersensitivity/immunology , Risk Factors , Surveys and QuestionnairesABSTRACT
Baker's asthma has long been recognized as a serious disease among workers in the bakery industry and the number of cases with baker's asthma is steadily increasing. This paper presents a review of the available literature on baker's allergy with a special focus on the allergens involved, the epidemiologic research and issues on exposure assessment, evidence of exposure-response-relationships, and possible prevention strategies. A large number of potential allergens have been identified and are described here. At present little is known about the incidence of baker's allergy. On the other hand, a large number of cross-sectional studies have been performed, showing that sensitization and work-related symptoms are common among bakery workers. Only atopy and exposure level have consistently been reported as determinants of this occupational disease. Age, gender, and smoking habits do not seem to be associated with sensitization or work-related respiratory symptoms. Recently, immunochemical methods have been developed to measure specific allergens in the bakery industry, which have been used to unravel the role of allergen exposure in the development of baker's asthma. Clear exposure-response-relationships have been found. The implications of these recent findings for prevention strategies and standard setting are discussed.
Subject(s)
Asthma/etiology , Cooking , Occupational Diseases/immunology , Allergens , HumansABSTRACT
OBJECTIVES: To follow up workers in the grain processing and animal feed industry five years after an initial survey, and to monitor exposures to organic dust and endotoxin and changes in prevalence of respiratory symptoms and lung function. METHODS: Outcome measures in the present survey were decline in lung function over five years, rapid annual decline in forced expiratory volume in one second (FEV1) above 90 ml.s-1, and loss to follow up. RESULTS: Among 140 workers included in the longitudinal analysis, annual decline in FEV1 and maximal mid-expiratory flow (MMEF) were significantly related to occupational exposure to dust and endotoxin in the grain processing and animal feed industry. Assuming a cumulative exposure over a working life of 40 years with an exposure of 5 mg.m-3, the estimated effect on the FEV1 would be a decline of 157 ml.s-1 (95% CI 13 to 300)--that is, about 4% of the group mean FEV1 and 473 ml.s-1 (95% CI 127 to 800) of the MMEF (about 12%). Workers with a dust exposure > 4 mg.m-3 or endotoxin concentrations > 20 ng.m-3 at the 1986-8 survey had significantly higher risk of rapid decline in FEV1 (odds ratio (OR) 3.3, 95% CI 1.02 to 10.3). The relations between occupational exposure and decline in lung function in this study occurred, despite the selection through the healthy worker effect that occurred as well. Increasing working years was related to decreasing annual decline in FEV1 and fewer people with rapid decline in FEV1 (OR 0.04, 95% CI 0 to 0.61 for over 20 v < 5 working years in the grain processing and animal feed industry). The presence of respiratory symptoms at baseline was a strong predictor of subsequent loss to follow up. Baseline lung function was not found to be predictive of subsequent loss to follow up. However, among workers lost to follow up the number of working years was more strongly negatively related to baseline lung function than among the workers who were studied longitudinally. CONCLUSIONS: The existence of the healthy worker effect implies that an exposure-response relation in the grain processing and animal feed industry may well be underestimated. This should be taken into account when health based recommended limit values are to be developed.
Subject(s)
Agricultural Workers' Diseases/etiology , Agriculture , Animal Feed/adverse effects , Dust/adverse effects , Edible Grain/adverse effects , Occupational Exposure/adverse effects , Adult , Analysis of Variance , Cough/etiology , Endotoxins/adverse effects , Female , Follow-Up Studies , Healthy Worker Effect , Humans , Inhalation Exposure/adverse effects , Longitudinal Studies , Male , Middle Aged , Netherlands/epidemiology , Pulmonary Ventilation , Regression Analysis , Respiratory Sounds , Risk Factors , Smoking/adverse effects , Time Factors , Vital CapacityABSTRACT
Two cases of desmoplastic form of ameloblastoma are reported. This tumor shows marked stromal desmoplasia and often scattered osteoplasia. The majority of stromal elements is represented by myofibroblasts. The epithelial component of this tumor is often scanty and different from epithelial islands of classic ameloblastoma. Pathological, immunohistochemical and radiological findings are described and the differential diagnosis of this tumor is discussed.
Subject(s)
Ameloblastoma/pathology , Jaw Neoplasms/pathology , Adult , Diagnosis, Differential , Female , Humans , Male , Middle AgedABSTRACT
Basically, two strategies can be considered for the analysis of hazardous pollutants in the work environment: group-based and individual-based strategies. This paper provides existing and recently derived equations for both strategies describing the influence of several factors on attenuation and on the standard error of an estimated linear regression coefficient relating a continuous exposure variable and a continuous health outcome via a simple linear regression model. We applied these equations using exposure variability information from industry-wide surveys over the past decade in order to gain more insight into the effects of various sources of exposure variability on choices among different analysis strategies. In general, for the modeling scenario considered here, there is not a straightforward criterion for choosing an optimal analysis strategy. Researchers have to decide between individual-based strategies generating precise, though biased, estimates or group-based strategies generating less precise but essentially unbiased estimates. For most exposure variability scenarios evaluated, an individual-based strategy yielded substantial attenuation. It is the authors' contention that the choice between individual-based and group-based strategies should be based on validity, rather than on precision, of the estimated exposure-response coefficient.
Subject(s)
Air Pollutants, Occupational/analysis , Linear Models , Occupational Exposure/analysis , Benzene/analysis , Humans , IndustryABSTRACT
This paper describes repeated measurements of inhalable flour dust, wheat allergens and alpha-amylase allergens in the bakery industry. A total of 571 full-shift personal dust samples was collected. Wheat allergens and alpha-amylase allergens were measured in 449 and 507 samples, respectively, by the use of recently developed immunoassays. For all three measures of exposure, the main components of exposure variability were determined. Different grouping strategies for studying exposure-response relationships were compared. The specific job of a bakery worker was identified as the most important source of variability in inhalable flour dust concentrations. For exposure to wheat allergens, the job performed was also the most important source of variation, but type of bakery also explained some of the variability. For alpha-amylase allergen exposure, information on type of bakery was more important then job information. For exposure to inhalable dust and wheat allergens, a classification by job title would lead to sufficient contrast in average exposure levels. By contrast, a grouping strategy based on a combination of job and type of bakery appeared to be essential to obtain a useful classification of exposure to alpha-amylase allergens. 1997 British Occupational Hygiene Society.
Subject(s)
Cooking , Dust , Flour , Occupational Exposure , Allergens , Humans , Triticum , alpha-AmylasesABSTRACT
BACKGROUND: In the baking industry the use of enzymes has increased throughout the 1980s. Several studies have reported sensitization and respiratory disorders among bakery workers caused by enzymes in dough improvers. Fungal alpha-amylase is the most frequently reported cause of allergy. alpha-Amylase allergen exposure levels in the bakery industry, however, have not yet been reported. OBJECTIVE: The main objective of this study was to quantify personal alpha-amylase exposure levels of bakery workers. METHODS: alpha-Amylase allergens were measured in 507 personal samples of airborne dust taken in bakeries by using a newly developed sandwich enzyme immunoassay with affinity-purified polyclonal rabbit IgG antibodies. A cascade impactor was used to estimate the size of dust particles carrying alpha-amylase allergens. RESULTS: The rabbit IgG antibodies used in the assay showed, in immunoblotting with commercially available alpha-amylase, a reaction profile very similar to that of IgE from sensitized bakers. The enzyme immunoassay appeared to be highly specific for fungal amylase. Allergen exposure levels varied considerably among bakery workers, depending on the type of bakery and job category (range, 0 to 40 ng/m3). In confectioneries no alpha-amylase allergens were detected. In other bakeries alpha-amylase exposure was only found for workers directly involved in dough making. Measurements of the particle size distribution in these bakeries showed that alpha-amylase allergens are most likely to be deposited in the nose and ciliated airways. CONCLUSION: This study shows that personal monitoring of fungal amylase allergen exposure in bakeries is possible. This permits the identification of high-risk tasks and allergen sources, as well as the study of exposure-response relationships.
Subject(s)
Air Pollutants, Occupational/analysis , Allergens/analysis , Amylases/analysis , Amylases/immunology , Food-Processing Industry , Occupational Exposure/analysis , Air Pollutants, Occupational/immunology , Allergens/immunology , Antigens, Fungal/analysis , Antigens, Fungal/isolation & purification , Dust/analysis , Environmental Monitoring , Enzyme-Linked Immunosorbent Assay , Epidemiological Monitoring , Humans , Immunoblotting , Immunoglobulin E/analysis , Immunoglobulin E/blood , Immunoglobulin E/immunology , Immunoglobulin G/immunology , Occupational Diseases/epidemiology , Occupational Diseases/immunology , Respiratory Hypersensitivity/epidemiology , Respiratory Hypersensitivity/immunology , Sampling Studies , Sensitivity and SpecificityABSTRACT
Fungal alpha-amylase is an important occupational allergen in the bakery industry. Epidemiologic studies focusing on the relationship between alpha-amylase allergen exposure and work-related respiratory allergy, however, have not been reported yet. In this cross-sectional study, sensitization to occupational allergens and work-related symptoms were studied in 178 bakery workers and related to allergen exposure. Alpha-amylase allergen concentrations were measured in personal dust samples, using a sandwich enzyme immunoassay. All workers were categorized into groups on the basis of their job histories and the alpha-amylase exposure levels of their job titles. Of all workers 25% had one or more work-related symptoms. As much as 9% of the bakery workers showed a positive skin prick test reaction to fungal amylase, and in 8% amylase-specific IgE was demonstrated. Alpha-amylase exposure and atopy appeared to be the most important determinants of skin sensitization, with prevalence ratios for atopy of 20.8 (95% CI, 2.74 to 158) and for medium and high alpha-amylase exposure groups of 8.6 (95% CI, 1.01 to 74) and 15.9 (95% CI, 1.95 to 129), respectively. Furthermore, a positive association was found between positive skin prick tests to alpha-amylase and work-related respiratory symptoms. In conclusion, this study has shown that there is a strong and positive relationship between alpha-amylase allergen exposure levels in bakeries and specific sensitization in bakery workers.
Subject(s)
Allergens , Asthma/etiology , Flour , Food Handling , Occupational Diseases/etiology , alpha-Amylases/adverse effects , Adult , Air Pollutants, Occupational/analysis , Aspergillus/enzymology , Asthma/diagnosis , Bread , Cross-Sectional Studies , Humans , Immunoglobulin E/analysis , Middle Aged , Occupational Diseases/diagnosis , Occupational Exposure , Skin Tests , alpha-Amylases/analysisABSTRACT
BACKGROUND: Asthma in bakery workers caused by exposure to wheat flour proteins is an important occupational health problem. Until recently, gravimetric dust measurements were the only available technique for quantitative exposure assessment in bakeries. However, it is questionable whether dust levels are a good exposure parameter or only give a crude approximation of the actual flour allergen concentration. OBJECTIVE: In the present study we have investigated a method to measure wheat flour antigens with immunochemical methods. METHODS: Wheat flour antigens were measured in 449 personal dust samples taken in bakeries, using enzyme-linked immunosorbent assay (ELISA) inhibition and an anti-wheat IgG4 serum pool. Western-blotting was performed to compare the wheat flour proteins detected by IgE and IgG4. RESULTS: Electrophoresis and immunoblotting showed that many wheat flour proteins can bind IgG4 and IgE, but also a reasonable similarity in major allergens detected by our IgG4-serum pool and IgE-positive sera. Inhibition tests showed some cross-reactivity with some cereal species, but not with other ingredients used in bakeries. In bakeries, large differences in personal airborne flour levels were found between occupational titles. For several groups clear differences in wheat antigen exposure levels existed, where no differences in dust exposure levels could be found. The relationship between dust and wheat antigen exposure varied considerably, depending on the specific bakery occupation, the size of the bakery, and the type of product produced by the bakery. This study also shows that personal sampling of wheat antigens is possible on a large scale and can be used for epidemiological field studies. CONCLUSION: Measurement of airborne wheat antigens in bakeries is a more specific and sensitive measurement tool than measuring dust samples, and will probably be essential for epidemiologic field studies focusing on exposure-response relationships.
Subject(s)
Air Pollutants, Occupational/analysis , Antigens/adverse effects , Antigens/analysis , Asthma/etiology , Occupational Diseases/etiology , Triticum/adverse effects , Asthma/epidemiology , Dust , Electrophoresis, Polyacrylamide Gel , Enzyme-Linked Immunosorbent Assay , Food-Processing Industry , Humans , Immunoblotting , Netherlands/epidemiology , Occupational Diseases/epidemiology , Triticum/chemistryABSTRACT
OBJECTIVE: Extensive IgE serology in occupational or environmental health studies is often hampered by a lack of technical facilities and finance. The use in population studies of relatively simple and inexpensive enzyme immunoassays (EIAs) was therefore evaluated for the assessment of total serum immunoglobulin E (IgE), and of specific IgE reactions with various common (house dust mites, grass and birch pollen, and cat) or occupational (fungal alpha-amylase and rat urinary protein) allergens. METHODS: Total IgE was measured with a sandwich EIA, calibrated with commercially available IgE standards. Reproducibility was studied by testing pooled normal human serum samples in each of a large series of test plates. A panel of 156 children's serum samples with known IgE values was used to compare the assay with other total IgE assays. A previously developed EIA for anti-yeast IgE was adapted for the measurement of IgE reacting with various common and occupational allergens. Binding of IgE to microwells coated with commercially available allergen extracts, or allergen preparations from our own laboratory, was measured with a monoclonal anti-human IgE antibody and subsequent incubations with biotinylated rabbit anti-mouse Ig and avidin-peroxidase. Panels of serum samples from school children (n = 116), bakery workers (n = 126), and laboratory animal workers (n = 52) were used to study sensitivity and specificity, with reference to skin prick tests as the standard, and to compare the EIAs with commercially available test kits. RESULTS: The detection limit of the EIA for total IgE was 0.5-1 kU/l for undiluted serum samples, and the coefficient of variation between assays was less than 15% at serum concentrations between 1 and 150 kU/l. Results obtained with the panel of 156 children's serum samples were strongly correlated (r2 = 0.86) with IgE concentrations measured previously by radioimmunoassay. The results of the EIA for various occupational allergens correlated very well, both qualitatively and quantitatively, with the results of commercial test kits. Sensitivity and specificity of the EIA results as a predictor of skin prick test reactivity towards common allergens (house dust mite, grass pollen, birch pollen, and cat) were remarkably high (> 80%-90%) in the series of 116 children's serum samples. In a population of bakery workers the specificity of the EIAs was also very high (> 90%). The sensitivity was notably lower (30%-70%) in this adult population, which is, however, in agreement with results reported for conventional IgE tests. CONCLUSION: As the costs were estimated to be at least five to 10-fold lower than those of commercial test kits, the EIAs for total and specific IgE may be very useful tools in epidemiological studies of atopic respiratory or other disorders.
Subject(s)
Allergens/immunology , Hypersensitivity, Immediate/diagnosis , Immunoglobulin E/blood , Population Surveillance/methods , Adult , Child , Humans , Immunoenzyme Techniques/economics , Sensitivity and SpecificityABSTRACT
In a study among 194 male workers exposed to endotoxin-containing organic dust in animal feed mills, lung function was measured by flow volume curves and impedance measurements and respiratory symptoms were recorded by means of a validated questionnaire. The aims were to detect and localize airway obstruction caused by fodder dust and endotoxin, and to relate respiratory symptoms to both types of lung function measurements. Flow volume and impedance parameters were significantly related to present exposure. All impedance parameters, of the spirometric measures only FEF25, were significantly related to cumulative dust or endotoxin exposure. The changes in impedance parameters were for overall increasing resistance at 8 Hz and decreasing reactance at 8 Hz, reflecting an increase in peripheral airflow obstruction, with increasing exposure. The changes in all lung function parameters were more strongly related to (cumulative) endotoxin exposure than to inspirable dust exposure. All impedance parameters and FEV1 showed a good correlation with complaints of chronic bronchitis and breathlessness. Impedance measurement of the respiratory system proved to be a useful tool for objectively assessing (early) airflow obstruction in workers exposed to inspirable dust and endotoxin and in localizing airflow obstruction.
Subject(s)
Animal Feed , Endotoxins/adverse effects , Pneumoconiosis/etiology , Adult , Air Pollutants, Occupational/analysis , Cross-Sectional Studies , Edible Grain , Humans , Male , Netherlands/epidemiology , Occupational Exposure , Occupations , Pneumoconiosis/diagnosis , Pneumoconiosis/epidemiology , Prevalence , Pulmonary Ventilation/physiology , Respiratory Function Tests , Sensitivity and SpecificityABSTRACT
Reported respiratory and related symptoms during work were compared between 265 exposed animal feed workers and a control group consisting of 175 external controls and nonexposed workers in the animal feed industry. Symptoms indicating respiratory and nasal irritation were significantly increased in the animal feed workers. Prevalences ranged from 9% (cough) to 21% (sneezing). Reported cough after work was also significantly increased. In 119 workers, a total of 457 across-shift spirometric lung function changes were measured. Almost all lung function variables showed a decrease during the work shift, as could be expected since the circadian rhythm is in a downward phase during the measurement period (2 p.m.-10 p.m.). When the workers were grouped into dust and endotoxin exposure categories according to their job titles, and exposure-response trend was seen for maximum mid-expiratory flow (MMEF) and maximum expiratory flow rate at 50% of vital capacity (MEF50). The effect of endotoxin was stronger than that of dust, both in magnitude and significance. For the same lung function variables and for forced expiratory volume in 1 second (FEV1) and MEF25, a significant across-week change was also detected. The results of this study are in concordance with other studies that indicate acute effects on lung function and elevated prevalences of respiratory symptoms during work caused by exposure to grain dust.
Subject(s)
Animal Husbandry , Dust/adverse effects , Endotoxins/adverse effects , Occupational Diseases/etiology , Respiratory Tract Diseases/etiology , Adult , Edible Grain , Humans , Male , Middle Aged , Netherlands , Occupational Diseases/physiopathology , Respiratory Function Tests , Respiratory Tract Diseases/physiopathologyABSTRACT
The study describes results of the first part of a follow-up study among 50 animal feed and grain elevator workers. The initial results suggest that the change in lung function over a 5 year period is related to the dust exposure. Workers in the high exposure category showed a greater decline in lung function than workers in the low exposure category. The decline in lung function was strongest for workers who were low exposed at the beginning of the study and who became high exposed during the follow-up period.
Subject(s)
Animal Husbandry , Dust/adverse effects , Occupational Exposure , Respiratory Mechanics , Adult , Follow-Up Studies , Forced Expiratory Volume , HumansABSTRACT
A cross-sectional study of 315 animal feed workers was undertaken in 14 animal feed mills in the Netherlands. Primary aims were to explore relationships between exposure to organic dust and respiratory symptoms and chronic lung function changes. The study comprised monitoring dust and endotoxin exposure, spirometric lung function measurements (FVC, FEV1, mean midexpiratory flow, and flow-volume parameters) and a questionnaire for respiratory symptoms. The exposure was measured in two periods, during spring and autumn. The average 8-h personal inspirable dust exposure was 9 mg/m3 grain dust (range, 0.2 to 150 mg/m3) and 25 ng/m3 endotoxin (range, 0.2 to 470 ng/m3) based on 530 personal dust measurements. On the basis of these measurements and the occupational history of the workers, the number of years "worked in dust" and an estimate of the cumulative dust and endotoxin exposure were calculated. The prevalence of most chronic respiratory symptoms tended to decrease with increasing years of exposure. The "healthy worker effect" is probably responsible for this finding. In general, a strong negative association between most of the exposure variables and lung function was found. The endotoxin exposure was more strongly related to decreases in lung function than the dust exposure. The estimated effects of an average (cumulative) endotoxin exposure on lung function were greater, with a higher statistical significance, than for an exposure to dust. These results suggest that endotoxin exposure is an important factor in the development of respiratory impairment. The lung function changes occur at endotoxin levels ranging from 0.2 to 470 ng/m3.