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Biomedical subjects

D Heederik

Publications and source records attributed to D Heederik.

At least 91 records · Page 5Linked to original sources
PubMed1997

Respiratory allergy in laboratory animal workers: a retrospective cohort study using pre-employment screening data.

OBJECTIVES: To study the role of exposure, atopy, and smoking in the development of laboratory animal allergy (LAA) in a retrospective cohort study. METHODS: Between 1977 and 1993, 225 people received a pre-employment screening when they started a job at a Dutch research institute where they were going to work with laboratory animals. After active follow up 136 of them (60.4%) could be traced and were sent a questionnaire with extensive questions on allergic symptoms, smoking habits, and job history. 122 people (89.7%) sent back a completed questionnaire. Those who were accepted for a job at the institute and did not have allergic symptoms at the start of the job were selected as cohort members. After selecting people with complete data on start and end date of jobs, exposure intensity, atopy, and smoking, the cohort consisted of 99 people with an average time of follow up of 9.7 years. LAA was defined as a positive response to a set of questions in the questionnaire. The mean number of hours a week a person was exposed to laboratory animals at entry of the cohort was used as a surrogate for exposure, and was divided into four categories. RESULTS: 19 cohort members (19.2%) reported LAA. More people with asthmatic symptoms were found in the high exposure categories. More atopic than non-atopic people reported asthmatic symptoms (13% v 6%). The mean time until development of symptoms of LAA was about 109 months in non-atopic people (n = 9), and 45 months in atopic people (n = 10) (t test; P < 0.05). Time until development of symptoms of LAA was shorter at a higher intensity of exposure, except for those exposed for less than two hours a week. A proportional hazard regression analysis showed that exposure and atopy were significant determinants of LAA. An increased relative risk (RR) was found for non-atopic people exposed to laboratory animal allergens for more than two hours a week. Atopic people had an even higher risk when exposed to laboratory animals for more than two hours a week (RR above 7.3). Sex, smoking, and age were not risk factors. More atopic than non-atopic people were absent from work or transferred because of allergies. CONCLUSIONS: This study showed that exposure and atopy are significant predictors of LAA and that the risk of developing LAA remained present for a much longer period (> 3 y) than considered before.

Animal Technicians↗
PubMed1997

Respiratory allergy to rats: exposure-response relationships in laboratory animal workers.

Laboratory animal workers are at high risk of developing occupational allergy. Little is known about the relationship between levels of exposure and the risk of developing laboratory animal allergy. A cross-sectional study was performed in 540 workers at eight facilities to quantify the exposure-response relationship for allergy to rats, while controlling for determinants like atopy, gender, and smoking. All participants completed a questionnaire, underwent skin prick testing with common and occupational allergens, and total IgE as well as occupational allergen-specific IgE antibodies were serologically measured. Personal air dust samples were taken during full-shift periods to estimate the rat urinary aeroallergen exposure levels. In the whole study population no clear exposure-response relationship was observed. However, in the group of workers with less than 4 yr of working experience with laboratory animals the prevalence rate of sensitization to rat allergens was clearly associated with exposure levels. The exposure-response relationship was steepest for workers with atopy-associated risk factors, i.e., self-reported allergy or sensitization to cats or dogs, or elevated total serum IgE. The prevalence rates of sensitization to rat allergens for these workers were about 15, 9.5, and 7.3 times higher in the high, medium, and low exposure group, respectively, compared with internal reference group.

Adult↗
PubMed1997

Exposure to Organic Dusts, Endotoxins, and Microorganisms in the Municipal Waste Industry.

The waste-collection and -processing industry in Europe is developing rapidly due to environmental constraints in the direction of separate collection, processing, and recycling of waste. It is likely that this will lead to an increase in the number of workers involved in the handling and processing of municipal waste, and an increase in the number of workers exposed to organic dust. This paper reports the results of an occupational hygiene study of the waste-collection and -processing industry (a compost-screening facility, a resource-recovery facility, and two waste-transfer facilities) in The Netherlands. It focuses on organic dusts, endotoxins, and microorganisms (total and gram-negative bacteria and fungi). Levels of exposure to inhalable organic dusts were highest in the waste-processing facilities (compost screening and resource recovery), with average concentrations for organic dusts up to 14.3 mg/m(3) during manual separation of waste and 9.7 mg/m(3) during compost screening activities. Personal endotoxin exposure was highest in the resource-recovery facility, ranging from 32.0 ng/m(3) for the supervisor to 131.1 ng/m(3) during manual separation of waste. High concentrations of microorganisms were found in all facilities. The highest levels for both total fungi and bacteria (<> 10&sup6; cfu/m(3)) were recorded in the dumping pit at the resource-recovery plant and in the dumping pit at one of the waste-transfer plants. It is concluded that high levels of exposures to microorganisms, and to a lesser extent organic dusts and endotoxins, are likely to occur in many processes and activities in the waste-transfer and -processing industry, and that the possibility of health effects due to these exposures cannot be excluded.

Journal Article↗
PubMed1997

Exposure of laboratory animal workers to airborne rat and mouse urinary allergens.

BACKGROUND: Laboratory animal workers are at high risk of developing occupational allergy. Little is known about the relationship between levels of exposure and the risk of developing laboratory animal allergy. Since laboratory animal work comprises a large number of different-often short lasting-tasks, it is of interest to assess which activities are associated with high, low or intermediate levels of allergen exposure. OBJECTIVE: To develop and evaluate highly sensitive immunoassays in order to quantify rat and mouse urinary allergens in airborne dust sampled during short-lasting tasks. METHODS: Personal air dust samples were taken during full-shift periods as well as during specific tasks in seven laboratory animal facilities. Two sandwich enzyme immunoassays were developed, using rabbit antisera against rat and mouse urinary proteins. The rabbit antibodies were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting and compared with IgE antibodies from sensitized laboratory animal workers. RESULTS: The rabbit antibodies were highly specific for rat and mouse urinary proteins and reacted with all IgE-binding allergens in either urinary protein preparation. The assays for rat and mouse urine were very sensitive, with detection limits of 0.075 ng/mL. The coefficient of variation of the analysis was 12.9% for both assays. Animal caretakers appeared to experience the highest exposure to aeroallergens. A large variation in exposure within jobs was found, due to differences between tasks performed during the sampling day and the facility worked at. The highest exposure levels were found during removal of contaminated bedding from the cages. However, rat and mouse allergen exposure levels during this task varied enormously between facilities, 1.1-158 ng eq/m3 and 0.63-2000 ng eq/m3, respectively. CONCLUSION: Both sandwich immunoassays are highly specific and sensitive and are able to identity tasks of relatively short duration with high, medium and low exposure to airborne rat and mouse urinary allergens.

Allergens↗
PubMed1996

Respiratory morbidity in relationship to farm characteristics in swine confinement work: possible preventive measures.

Swine confinement farming is associated with an increased risk of respiratory morbidity. Adverse health effects have been shown in association with levels of dust, endotoxins, and ammonia. This study was conducted to evaluate characteristics of confinement farms associated with respiratory morbidity in order to establish priorities for preventive measures. A questionnaire on symptoms and farm characteristics was completed by 1,432 male swine confinement farmers. Of these, 200 with and 200 without chronic respiratory symptoms were randomly selected for lung function testing. A significantly increased risk for chronic respiratory symptoms was shown if farmers used wood-shavings as bedding (prevalent odds ratio [POR]2.2), used disinfectants (POR 1.7), used natural ventilation (POR 2.6), had floor types other than slatted or half-slatted (POR 2.1), or used a mechanical feeding system (POR 1.4). Lung function (FEV1) was significantly lower with increasing numbers of years worked (51 ml/10 years), with smaller numbers of pigs (8.5 ml/100 pigs), and when the air outlet of the ventilation system was via the pit (248 ml). To decrease the risk of respiratory morbidity the following preventive measures are proposed: discouragement of the use of disinfectants and of wood-shavings as bedding, and promotion of the use of mechanical ventilation systems.

Agricultural Workers' Diseases↗
PubMed1996

Cat and dog allergy and total IgE as risk factors of laboratory animal allergy.

BACKGROUND: Laboratory animal workers are at high risk of developing occupational allergy. In many cases the severity of allergy symptoms makes further work with laboratory animals impossible. OBJECTIVE: This study was designed to estimate prevalence rates of sensitization and symptoms of allergy in a population of laboratory animal workers and to determine the association between various host factors and these prevalence rates. METHODS: A cross-sectional survey was undertaken in 540 workers at eight facilities in the Netherlands. All participants completed a questionnaire and underwent skin prick testing with common and occupational allergens. In addition, total and specific IgE measurements were obtained. RESULTS: Prevalence rates of allergy symptoms caused by working with rats and mice were 19% and 10%, respectively. Symptoms, especially chest tightness, were strongly related to sensitization. Rat and mouse allergy, defined as symptoms of allergy accompanied by specific atopic sensitization, were highly associated with elevated total IgE, reported adverse reactions, and positive skin prick test responses to common allergens. This relationship could be explained by a response to cat or dog allergens. CONCLUSIONS: Allergy to cats or dogs seemed to be an important risk factor for laboratory animal allergy, whereas allergy to pollen or house dust mite, in the absence of cat and dog allergy, appeared to be insignificant. More conclusive evidence about cat and dog allergy preceding laboratory animal allergy can only be provided after analysis of follow-up data.

Allergens↗
PubMed1996

Choosing optimal values of FEV1 and FEV1/FVC for surveillance for respiratory disorders in occupational populations.

Pulmonary lung-function testing plays an important role in surveillance programs for occupational respiratory disorders. Spirometry is usually utilized by applying preset cut-off values to discriminate between healthy and unhealthy subjects. This article demonstrates the usefulness of decision analysis techniques to arrive at an optimal diagnosis. The diagnostic performance of FEV1 and FEV1/FVC was evaluated by relative operating characteristics curves (ROCs) applied to data of a cohort gathered in 1965. Both parameters showed quite similar ROCs, with a maximal sensitivity of 40% at a specificity of 95% relative to the physician's diagnosis of respiratory disorder. The area under the curves was. 75 for both FEV1 and FEV1/FVC, illustrating that misclassification of 25% of the subjects is likely to occur. Regarding the consequences of a false-positive and a false-negative decision as of equal importance, the 5%-percentile (FEV1 residual less than -1.2 L) would be the optimal cut-off. An FEV1 residual below the lower 5%-percentile was six times more likely to appear in subjects with chronic nonspecific lung disease (CNSLD) than in subjects without. The post-test probability of CNSLD was three to four times the pre-test probability. In occupational or public health practice, however, false-positive results need to be avoided, even at the expense of a higher false-negative rate. In those situations, a more rigid cut-off between normal and abnormal values may be warranted.

Adult↗
PubMed1996

Wheat antigen exposure assessment for epidemiological studies in bakeries using personal dust sampling and inhibition ELISA.

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.

Air Pollutants, Occupational↗
PubMed1996

Measurement of beta(1-->3)-glucans in occupational and home environments with an inhibition enzyme immunoassay.

beta (1-->3)-Glucans are known for their potent ability to induce nonspecific inflammatory reactions and are believed to play a role in bioaerosol-induced respiratory symptoms. An inhibition enzyme immunoassay (EIA) was developed for the quantitation of beta (1-->3)-glucans in dust samples from occupational and residential environments. Immunospecific rabbit antibodies were produced by immunization with bovine serum albumin-conjugated laminarin [beta (1-->3)-glucan] and affinity chromatography on epoxy-Sepharose-coupled beta (1-->3)-glucans. The laminarin-based calibration curve in the inhibition EIA ranged from approximately 40 to 3,000 ng/ml (15 to 85% inhibition). Another beta (1-->3)-glucan (curdlan) showed a similar inhibition curve but was three to five times less reactive on a weight basis. Pustulan, presumed to be a beta (1-->6)-glucan, showed a parallel dose-response curve at concentrations 10 times higher than that of laminarin. Control experiments with NaIO4 and beta (1-->3)-glucanase treatment to destroy beta (1-->6)- and beta (1-->3)-glucan structures, respectively, indicate that the immunoreactivity of pustulan in the assay was due to beta (1-->3)-glucan and not to beta (1-->6)-glucan structures. Other polysaccharides, such as mannan and alpha (1-->6)-glucan, did not react in the inhibition EIA. Beta (1-->3)-Glucan extraction of dust samples in water (with mild detergent) was performed by heat treatment (120 degrees C) because aqueous extracts obtained at room temperature did not contain detectable beta (1-->3)-glucan levels. The assay was shown to detect heat-extractable beta (1-->3)-glucan in dust samples collected in a variety of occupational and environmental settings. On the basis of duplicate analyses of dust samples, a coefficient of variation of approximately 25% was calculated. It was concluded that the new inhibition EIA offers a useful method for indoor beta (1-->3)-glucan exposure assessment.

Animals↗
PubMed1996

Comparison of dust related respiratory effects in Dutch and Canadian grain handling industries: a pooled analysis.

OBJECTIVES: Four previously conducted epidemiological studies in more than 1200 grain workers were used to compare exposure-response relations between exposure to grain dust and respiratory health. METHODS: The studies included Dutch workers from an animal feed mill and a transfer grain elevator and Canadian workers from a terminal grain elevator and the docks. Relations between forced expiratory volume in one second (FEV1) and exposure were analysed with multiple regression analysis corrected for smoking, age, and height. Exposure variables examined included cumulative and current dust exposure and the numbers of years a subject was employed in the industry. Sampling efficiencies of the Dutch and Canadian measurement techniques were compared in a pilot study. Results of this study were used to correct slopes of exposure-response relations for differences in dust fractions sampled by Dutch and Canadian personal dust samplers. RESULTS: Negative exposure-response relations were shown for regressions of FEV1 on cumulative and current exposure and years employed. Slopes of the exposure-response relations differed by a factor of three to five between industries, apart from results for cumulative exposure. Here the variation in slopes differed by a factor of 100, from -1 to -0.009 ml/mg.y/m3. The variation in slopes between industries reduced to between twofold to fivefold when the Dutch transfer elevator workers were not considered. There was evidence that the small exposure-response slope found for this group is caused by misclassification of exposure and a strong healthy worker effect. Alternative, but less likely explanations for the variation in slopes were differences in exposure concentrations, composition of grain dust, exposure characteristics, and measurement techniques. CONCLUSION: In conclusion, this study showed moderately similar negative exposure-response relations for four different populations from different countries, despite differences in methods of exposure assessment and exposure estimation.

Adult↗
PubMed1996

Disinfectant use as a risk factor for atopic sensitization and symptoms consistent with asthma: an epidemiological study.

Exposure to some nonallergenic compounds has been shown to increase the risk of atopic sensitization and asthmatic symptoms. In order to gain more insight into the largely unknown aetiology of respiratory symptoms in pig farmers, we studied the role of nonallergic exposure. We evaluated associations between chronic respiratory symptoms, specific and total serum immunoglobulin E (IgE) levels, use of disinfectants, and endotoxin exposure levels in a population of 194 Dutch pig farmers. Atopic sensitization (defined as increased production of IgE to common allergens) was found to occur more frequently in farmers who used disinfectants containing quaternary ammonium compounds (QACs) (odds ratio (OR) 7.4; 95% confidence interval (95% CI) 1.3-43.1). ORs for other disinfectants ranged 2.3-4.1 (NS). Atopic sensitization was not found to occur more frequently in farmers with a high endotoxin exposure. The use of disinfectants was only related to respiratory symptoms consistent with asthma in atopics. This is illustrated by the significantly elevated ORs for farmers with IgE to common allergens (house dust mite, grass pollen, birch pollen), and who used disinfectants containing QACs, in the total population and in a subgroup of the total population restricted according to bronchial hyperresponsiveness to histamine (symptomatics with a provocation dose of histamine producing a > or = 10% decrease in forced expiratory volume in one second (PC10) < or = 16 mg.mL-1, compared with asymptomatics with a PC10 > 16 mg.mL-1) (OR 4.4, 95% CI 1.3-14.6; and OR 8.2, 95% CI 1.6-42.6, respectively). Atopy and use of QACs and endotoxin exposure level taken individually were not associated with respiratory symptoms. A combination of atopic sensitization and high endotoxin exposure (> 101 ng.m-3) was strongly associated with respiratory symptoms in the restricted population (OR 6.1; 95% CI 1.0-36.2). Our results suggest that occupational exposure to nonallergenic agents (disinfectants) may induce immunoglobulin E sensitization to common aeroallergens, and that the combination of atopy and exposure to nonallergenic agents (disinfectants and endotoxin) is an important risk factor for development of symptoms consistent with asthma.

Adult↗
PubMed1996

Experts' subjective assessment of pesticide exposure in fruit growing.

OBJECTIVES: Exposure to pesticides in fruit growing was estimated by pesticide experts, occupational hygienists, and fruit growing experts to determine whether valid subjective assessments can be made by experts. The study objectives were (i) validation of exposure assessment by experts using different sources of information, (ii) assessment of interrater agreement, (iii) measurement of agreement between experts' assessments and actual quantitative exposure data. METHODS: Three groups with different expertise made four ratings. Three of the ratings were made in three phases in which exposure information was provided. RESULTS: The intraclass correlation was high for each subgroup of experts when tasks in fruit growing were relatively ranked by increasing exposure level. In general, the interrater agreement on factors influencing the internal dose decreased when more information on exposure was provided. Experts correctly considered dermal exposure as the prominent contributor to internal dose. Results were comparable for the three pesticides under study. The ranking of 15 specific sprayings with a fungicide clearly showed differences between raters according to their expertise. The pesticide experts and occupational hygienists were able to rank daily exposure levels during pesticide spraying in a meaningful way. CONCLUSIONS: Experts seem to recognize the most important determinants of external exposure and therefore should be able pay a role in evaluating the effectiveness of control measures taken to reduce external exposure and to determine exposure groups in epidemiologic studies. The expert panel should not be too small, and consensus or average estimates should be used because differences within expert groups can be considerable.

Agriculture↗
PubMed1996

Airborne dust antigen exposure and specific IgG response in the potato processing industry.

BACKGROUND: High prevalences of work-related respiratory symptoms in relation to organic dust exposure have been reported in the potato processing industry, but the responsible effect mechanisms are not known. OBJECTIVE: To study the possible role of a type III allergy in aetiology. METHODS: Specific immunoglobulin G (IgG) and IgG4 subclass antibodies against occupational airborne antigens were determined in sera from 131 potato processing workers and 36 non-exposed controls. Personal exposure to airborne antigens was measured, and a preliminary biochemical characterization was carried out. RESULTS: Specific IgG was detectable in almost all sera, but levels were significantly (P < 0.01) higher in potato processing workers compared with controls. Specific IgG4 was detectable in half of the workers' sera, but in none of the control sera. The antigens involved appeared to be heat-labile potato proteins. Antibody levels increased during the processing campaign in most workers, and this increase was dependent on the level of antigen exposure. Both the difference in IgG titres between the occupationally exposed group and the non-exposed group, and the exposure-related increase in specific IgG titres seemed to be mainly due to specific antibodies of the IgG4 subclass. Specific antibodies showed a non-significant tendency to lower levels in workers with work-related respiratory symptoms. CONCLUSION: Occupational respiratory exposure in the potato processing industry leads to a strong humoral immune response, most pronounced for IgG4 subclass antibodies. Type III allergy is, however, unlikely to play a predominant role in the aetiology of respiratory effects.

Air Pollutants↗
PubMed1995

Occupational epidemiology in the rubber industry: implications of exposure variability.

The variability of exposure has important implications for the design of occupational epidemiologic studies. To assess the influence of this variability in the rubber industry, the efficiency of different schemes for classification of exposure to particulates, cyclohexane-soluble contaminants, and solvents was assessed. Groupings based on job title, plant, factors affecting exposure, published classifications, and the International Standard Classification of Occupations of the International Labor Organization (ISCO-ILO) were compared. Statistical parameters for contrast in average exposure between groups and precision of average exposure within groups were developed to enable comparison of the efficiency of different classification schemes. Grouping of exposure to particulates and dermal exposure appeared to be less efficient than grouping of exposure to solvents. Grouping of solvent exposure using occupational title groups, existing classification schemes, and schemes based on factors affecting exposure showed comparable high resolution in exposure levels. Even the most detailed grouping schemes based on the combination of plant and occupational title group showed relatively modest resolution in particulate and dermal exposure levels. Groupings based on factors affecting exposure showed similar resolution for these exposures, but had higher precision due to having fewer groups. Application of optimal exposure grouping strategies will benefit new research on cancer among rubber workers. Eventually, this might resolve the situation in which a complete industry was included on the list of proven human carcinogens.

Analysis of Variance↗
PubMed1995

Urinary excretion of tetrahydrophtalimide in fruit growers with dermal exposure to captan.

The relation between dermal and respiratory exposure and uptake into the body of captan, measured as 24 hr cumulative tetrahydrophtalimide (THPI) dose, was studied among 14 male fruit growers applying pesticides in orchards in the Netherlands. No contribution of respiratory exposure was observed on THPI in the urine. Dermal exposure, measured with skin pads, showed a clear relation with THPI in urine when exposure was estimated from exposure on skin pads of ankles and neck. No relation was found for total dermal exposure, calculated from measured exposure on skin pads of representative skin areas according to models described in the literature. Determinants of exposure such as use of a cabin on the tractor, use of gloves during mixing and loading, and use of rubber boots also explained THPI in urine very well. This finding corroborated the findings on measured dermal exposure. Results indicate that more attention should be paid to skin areas which are suspected to be most permeable for a chemical under study. It was concluded that dermal exposure data can be linked better to biological monitoring based on empirical findings as gathered in a pilot study on exposure of specific body areas than on estimations of total skin dose.

Adult↗
PubMed1995

Influence of various dust sampling and extraction methods on the measurement of airborne endotoxin.

The influence of various filter types and extraction conditions on the quantitation of airborne endotoxin with the Limulus amebocyte lysate test was studied by using airborne dusts sampled in a potato processing plant. Samples were collected with an apparatus designed to provide parallel samples. Data from the parallel-sampling experiment were statistically evaluated by using analysis of variance. In addition, the influence of storage conditions on the detectable endotoxin concentration was investigated by using commercially available lipopolysaccharides (LPS) and endotoxin-containing house dust extracts. The endotoxin extraction efficiency of 0.05% Tween 20 in pyrogen-free water was seven times higher than that of pyrogen-free water only. Two-times-greater amounts of endotoxin were extracted from glass fiber, Teflon, and polycarbonate filters than from cellulose ester filters. The temperature and shaking intensity during extraction were not related to the extraction efficiency. Repeated freeze (-20 degrees C)-and-thaw cycles with commercial LPS reconstituted in pyrogen-free water had a dramatic effect on the detectable endotoxin level. A 25% loss in endotoxin activity per freeze-thaw cycle was observed. Storage of LPS samples for a period of 1 year at 7 degrees C had no effect on the endotoxin level. House dust extracts showed a decrease of about 20% in the endotoxin level after they had been frozen and thawed for a second time. The use of different container materials (borosilicate glass, "soft" glass, and polypropylene) did not result in different endotoxin levels. This study indicates that the assessment of endotoxin exposure may differ considerably between groups when different sampling, extraction, and storage procedures are employed.

Air Pollutants↗
PubMed1995

Lung function and chronic respiratory symptoms of pig farmers: focus on exposure to endotoxins and ammonia and use of disinfectants.

OBJECTIVES: The prevalence of chronic respiratory symptoms among pig farmers is known to be high, but the aetiology of these symptoms is not yet unravelled. Long term average exposure to dust was evaluated, endotoxins and ammonia and use of disinfectants were compared with chronic respiratory symptoms and depressed base line lung function. METHODS: A cross sectional study was performed among 194 Dutch pig farmers, of whom 100 had not and 94 had chronic respiratory symptoms. Exposure-response relations were evaluated with multiple logistic and linear regression analysis. Estimates of long term average exposure were based on two personal exposure measurements, taken on one day in summer and one day in winter. Information on use of disinfectants and disinfection procedures was assessed by a walk through survey and interview by telephone. RESULTS: Exposure to dust, endotoxins, and ammonia were not related to chronic respiratory symptoms. Duration of the disinfection procedure and pressure used at disinfection were strongly and positively related to chronic respiratory symptoms. A significant inverse association between base line lung function and endotoxin exposure was found only among asymptomatic farmers. Ammonia exposure and duration of the disinfection procedure were significantly associated with base line lung function in the entire population. CONCLUSION: Results suggest that use of disinfectants is an important aetiological factor in chronic respiratory health effects of pig farmers. This factor has not been studied before. Results also suggest an aetiological role for exposure to endotoxins and ammonia in development of chronic respiratory health effects, but longitudinal studies with detailed exposure assessment strategies are required to assess their roles.

Adult↗