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Biomedical subjects

D Heederik

Publications and source records attributed to D Heederik.

At least 19 recordsLinked to original sources
PubMed2001

Chronic obstructive pulmonary disease and intake of catechins, flavonols, and flavones: the MORGEN Study.

Flavonoids have been suggested to protect against chronic lung disease. We studied intake of catechins, flavonols, and flavones in relation to pulmonary function and COPD symptoms in 13,651 adults from three Dutch cities examined from 1994 to 1997. Dietary intake was estimated using a food frequency questionnaire, and flavonoid intake was calculated using specific food composition tables. Pulmonary function (FEV1) was determined by spirometry and COPD symptoms by questionnaire. Associations were presented for the fifth versus the first quintile of intake (Q5-Q1), adjusted for age, height (for FEV1 only), sex, smoking, BMI, and energy intake. Smoking was strongly associated with COPD, independent of dietary effects. Average catechin, flavonol, and flavone intake was 58 mg/d (SD = 46) with tea and apples as main sources. Total catechin, flavonol, and flavone intake was positively associated with FEV1 (beta(Q5-Q1) = 44 ml, 95% CI = 18-69) and inversely associated with chronic cough (OR(Q5-Q1) = 0.80, 95% CI = 0.66-0.97) and breathlessness (OR(Q5-Q1) = 0.74, 95% CI = 0.58- 0.94), but not chronic phlegm. Catechin intake was independently associated with FEV1 (beta(Q5-Q1) = 130 ml, 95% CI = 101-159) and all three COPD symptoms (OR(Q5-Q1) = 0.60-0.72, p < 0.001). Flavonol and flavone intake was independently associated with chronic cough only. Solid fruit, but not tea, intake was beneficially associated with COPD. Our results suggest a beneficial effect of a high intake of catechins and solid fruits against COPD.

Adult↗
PubMed2001

Respiratory effects of exposure to low levels of concrete dust containing crystalline silica.

BACKGROUND: Dusts containing crystalline silica are generated in mining, construction, glass, granite and concrete production industries. The association between exposure to low levels of concrete dust containing crystalline silica and reduction in lung function, was evaluated in a cross-sectional study. METHODS: The study was carried out among 144 concrete workers, from two factories, with exposure assessment of respirable dust and silica by personal samplers. Results of respiratory questionnaires and standardized measurements of lung function were compared with the results in a control population. Multiple linear regression analysis was used in selecting factors that predict (age and standing height standardized residual) lung function. RESULTS: The average concentration of respirable dust in both factories was 0.8 mg/m(3) and 0.06 mg/m(3) for respirable silica. The average silica content of the dust was 9%. The average cumulative dust exposure was 7.0 mg/m(3) year and cumulative silica exposure was 0.6 mg/m(3) year. Significant associations between exposure to concrete dust and a small lung function (FEV(1)/FVC ratio, MMEF) loss were found, independent of smoking habits and of a history of allergy. CONCLUSIONS: Our results indicate that, concrete workers with chronic obstructive pulmonary symptoms and/or work-related lower respiratory symptoms are at risk of having a reduction in lung function (FEV&(1)/FVC ratio) outside the 5th percentile of the external reference population, and therefore, of mild chronic obstructive pulmonary disease, at respirable concrete dust levels below 1 mg/m(3) with a respirable crystalline silica content of 10% (TWA, 8 hr).

Adult↗
PubMed2001

Diet and chronic obstructive pulmonary disease: independent beneficial effects of fruits, whole grains, and alcohol (the MORGEN study).

BACKGROUND: In recent years antioxidants, foods rich in antioxidants (e.g. fruits, vegetables) and fish have been suggested to protect against chronic obstructive pulmonary disease (COPD). There are also indications for a protective effect of whole grain intake and of consuming moderate amounts of alcohol. It is, however, not clear whether the effects of the different dietary factors on COPD are independent of each other and if so, whether their effects are additive. OBJECTIVE: To gain more insight into the potential protective effect of diet on COPD, we studied fruit, vegetable, fish, alcohol and whole grain consumption simultaneously in relation to pulmonary function and COPD symptoms. METHODS: Analysed were cross-sectional data collected in 13 651 men and women aged 20-59 years participating between 1994 and 1997 in the MORGEN study (monitoring project on risk factors and health in The Netherlands). Regression models were adjusted for age, gender, height (for pulmonary function only), smoking, BMI and energy intake. RESULTS: Fruit and whole grain intake showed independent beneficial associations with COPD (P-trend < 0.001). Furthermore, in subjects with low alcohol consumption (1-30 g/day) the forced expiratory volume in 1 s (FEV1) was higher and the prevalence of COPD symptoms lower than in non-drinkers (P < 0.001). The effects of a favourable intake of fruits (> 180 g/day), whole grains (> 45 g/day) and alcohol (1-30 g/day) were largely additive. In the 2998 subjects with a favourable intake of the three foods, the FEV1 was 139 mL higher and the prevalence of COPD symptoms lower (odds ratio (OR) = 0.44) than in subjects (n = 1406) with unfavourable intakes of fruits, whole grains and alcohol (P < 0.001). A similar effect was observed in those who had never smoked. Fish and vegetable intake did not show independent beneficial associations with COPD. CONCLUSIONS: Our results suggest independent beneficial effects of fruits, whole grains and alcohol on COPD that are largely additive and cannot be explained by smoking habits.

Adult↗
PubMed2001

Alcohol consumption in relation to 20-year COPD mortality and pulmonary function in middle-aged men from three European countries.

Alcohol consumption shows a U-shaped relation with all-cause and cardiovascular mortality. To determine whether a similar relation exists between alcohol and chronic obstructive pulmonary disease mortality, we analyzed data on alcohol consumption in 1970 and 20-year mortality from chronic obstructive pulmonary disease among 2,953 middle-aged men from Finland, Italy, and the Netherlands. We also studied alcohol consumption in relation to pulmonary function (FEV1 or FEV0.75) at baseline. We used regression models adjusted for age, height (for pulmonary function only), body mass index, smoking habits, energy intake, and country. A smoothed spline-plot showed a U-shaped relation between alcohol and chronic obstructive pulmonary disease mortality. Compared with non-drinkers and occasional drinkers, the relative risk of chronic obstructive pulmonary disease mortality was 0.60 (95% CI = 0.33-1.09) in light drinkers (> 1 drink per week, < or = 3 drinks per day) and 1.25 (95% CI = 0.47-3.31) in moderate-to-heavy drinkers. Pulmonary function was lower in non-drinkers compared with occasional and light drinkers in Finland (75 ml, 95% CI = -2 to 151) and the Netherlands (93 ml, 95% CI = 0-186) and lower in very heavy (> 12 drinks per day) compared with moderate-to-heavy drinkers in Italy (99 ml, 95% CI = 9-189). In conclusion, we observed a U-shaped curve between alcohol consumption and 20-year chronic obstructive pulmonary disease mortality in middle-aged men that was supported by cross-sectional data on alcohol and pulmonary function.

Adult↗
PubMed2001

Short term exposure to airborne microbial agents during farm work: exposure-response relations with eye and respiratory symptoms.

OBJECTIVES: Exposure to high levels of non-infectious microbial agents is recognised as a cause of respiratory disease in working populations, but except for endotoxins, little is known about exposure-response relations. As these effects do not depend on viability, exposure to non-viable microbial agents is important. Various methods not based on microbial cultures were explored to study the complex microbial exposure of farmers and associations with acute symptoms during work. METHODS: Airborne exposure was measured when farmers carried out specific tasks. Fungal spores, bacteria, endotoxins, beta(1-->3)-glucans, fungal antigens specific for Penicillium and Aspergillus species, and mites were measured by methods not based on microbial cultures. Also silica, inorganic and organic dust, ammonia, hydrogen sulphide, and nitrogen dioxide were measured. Respiratory, and nose and eye symptoms experienced during measurements were recorded by a short questionnaire. Both univariate and multivariate statistical analyses were applied to assess the relations between exposure and acute symptoms. RESULTS: 106 Farmers and their spouses participated in this study. Prevalences of work related symptoms were: wheezing 3%; chest tightness 7%; cough 14%; eye symptoms 18%; and nose symptoms 22%. Prevalence ratios for nose and eye symptoms were 4-8 after exposure to 20-500x10(3) fungal spores/m(3) and higher, and a prevalence ratio for cough was 4 after exposure to 500-17,000x10(3) fungal spores/m(3). Nose symptoms were also associated with exposure to silica with prevalence ratios of 4-6 after exposure to 0.015-0.075 mg /m(3) and higher. CONCLUSIONS: Farmers had a high occurrence of symptoms of the nose and eyes as well as cough during work. These symptoms were associated in a dose dependent manner with exposure to fungal spores. Nose symptoms were also associated with exposure to silica.

Aged↗
PubMed2001

An exploratory quantitative risk assessment for high molecular weight sensitizers: wheat flour.

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.

Adolescent↗
PubMed2001

Work-related symptoms in sewage treatment workers.

The aim of this study was to investigate health symptoms in sewage treatment workers. A health questionnaire was distributed among 147 sewage treatment workers. Correlating symptoms were clustered using principal component analysis and the association with self-reported exposure was assessed by calculating prevalence odds ratios (OR). Endotoxin was measured in two treatment plants. Personal endotoxin exposure was low (<10 Endotoxin Units/m(3)). Factor analysis of 29 symptoms resulted in four clusters of highly correlating symptoms: 'flu-like symptoms'; 'higher airway symptoms'; 'lower airway symptoms'; and 'neurological symptoms'. These clusters were positively associated with working with sewage, but only significant for 'flu- like symptoms' (OR=5.0; 95%CI=1.4-17.6; p<0.05) and 'neurological symptoms' (OR=4.2; 95%CI=1.5-11.7; p<0.01). Chemical exposure was associated with 'neurological symptoms' (OR=8.4; 95%CI=1.1-65.7; p<0.05). The use of daily washed working clothes was negatively associated with 'flu-like symptoms' (OR=0.3; 95%CI=0.1-0.6; p<0.01). In conclusion, sewage treatment workers develop a large variety of work-related symptoms that are not likely caused by endotoxin exposure only. Good hygienic practice at the workplace may prevent some of these symptoms

Adult↗
PubMed2000

Characterization of dust exposure for the study of chronic occupational lung disease: a comparison of different exposure assessment strategies.

Various exposure assessment strategies were compared in the study of the relation between dust exposure and 11-year lung function change in 1,172 miners with 36,824 concurrently measured personal dust samples available from the 1969-1981 US National Study of Coal Workers' Pneumoconiosis. A miner's average exposure was assessed by calculating average exposures based on dust samples taken from each individual and by using different job exposure matrices (JEMs) with different underlying exposure categorizations, based on occupational categories, job title, mine, and time, to obtain average exposure estimates. For each grouping procedure, intragroup and intergroup variances and the pooled standard error of the mean were calculated to assess relative efficiency. The results show that considerable variation in slopes of exposure-response relations was found using different exposure assessment strategies. Standard errors of the slopes of the exposure-response relations with exposure on an individual basis compared with JEMs. Exposure assessment on an individual basis was extremely sensitive to the number of exposure measurements per individual. The study demonstrates the advantages and disadvantages of different exposure assessment strategies and shows the need for explicit publication of exposure assessment strategies for epidemiologic studies. Careful assessment of the influence of misclassification error in the exposure assessment on exposure-response modeling is warranted.

Adult↗
PubMed2000

Upper airway inflammation assessed by nasal lavage in compost workers: A relation with bio-aerosol exposure.

BACKGROUND: Exposure to microbial agents in the composting industry may cause work related airway inflammation. Nasal lavage (NAL) has been proposed as a noninvasive method to assess such effects in population studies. METHODS: Pre- and post-shift NAL were performed in the workers of a compost plant visited in 1995 (n = 14) and 1996 (n=15), of whom only four participated in both surveys. Total cells, cytokines and other inflammation markers were measured in NAL fluid, and pre-shift levels and post/pre concentration ratios were compared with NAL results obtained in the same periods in 10 and 9 controls, respectively, and with levels of airborne exposure to microbial agents endotoxin and beta(1,3)-glucan as measured in personal air samples. RESULTS: Job-title specific exposure levels in the first survey ranged from 75 to 527 EU/m(3) for endotoxin and from 0.54 to 4.85 microg/m(3) for beta(1,3)-glucan. In the second survey these values were lower, 29-285 EU/m(3) and 0.36-4.44 microg/m(3), respectively. In the first survey pre-shift NAL concentrations of total cells, MPO, IL-8, NO and albumin were significantly (1.1-4.8 fold) higher in compost workers than in controls. Post/pre ratios for various markers were significantly (1.2-3.2 fold) higher in compost workers in both surveys. NAL cells were mainly neutrophils, while eosinophils were only incidentally observed. A weak relation with exposure was found for pre-shift levels of MPO, uric acid and urea in the first survey. CONCLUSIONS: Occupational exposure of compost workers may cause acute and possibly (sub-)chronic inflammatory reactions in the upper airways, presumably induced by non-allergenic pro-inflammatory agents like endotoxins and beta(1, 3)-glucans.

Adult↗
PubMed2000

Worker exposures to airborne dust, endotoxin and beta(1,3)-glucan in two New Zealand sawmills.

BACKGROUND: Sawmill workers have an increased risk of developing occupational asthma and other respiratory symptoms. Wood dust and microorganisms have both been suggested to play a role, but few studies have measured microbial exposure levels in sawmills. METHODS: The preliminary study reported in this paper assessed airborne dust, bacterial endotoxin and beta(1,3)-glucan levels in 37 samples from two New Zealand sawmills. RESULTS: Nearly one-third of the measured dust levels exceeded 1 mg/m(3) and only one sample exceeded the legal limit of 5 mg/m(3). Endotoxin levels were clearly elevated with 50% of all measured exposures above 50 EU/m(3) (range: 7-588 EU/m(3)). beta(1,3)-glucan levels were comparable with levels measured in other industries where workers are exposed to organic dust. Workers in the planing department had the highest mean exposures to dust, endotoxin and beta(1,3)-glucan. Dust levels were only weakly correlated with endotoxin and beta(1,3)-glucan levels. CONCLUSIONS: Endotoxin exposures in sawmill workers are at levels sufficient to potentially contribute to the development of respiratory symptoms. Moreover, measurement of dust exposure is a poor proxy for beta(1,3)-glucan and endotoxin exposure in sawmill workers.

Dust↗
PubMed2000

Paternal occupational exposures and embryo implantation rates after IVF.

OBJECTIVE: To investigate any influence of paternal occupational exposures on implantation rates after IVF. DESIGN: Cohort study of couples who sought IVF treatment. SETTING: University Hospital Utrecht, The Netherlands. PATIENT(S): The study population was composed of 726 couples pursuing IVF treatment. INTERVENTION(S): Only the earliest IVF treatment cycle with ET was selected for the analysis. All couples filled in a generic questionnaire on lifestyle factors and details about their occupation. In addition, more detailed exposure information was obtained for pesticides with use of job-specific questionnaires and a subsequent telephone interview. MAIN OUTCOME MEASURE(S): The implantation rate was defined as the number of gestational sacs seen with ultrasound at 6-7 weeks of pregnancy, divided by the number of embryos replaced. RESULT(S): A significantly reduced implantation rate was seen among couples with male partners working in occupations with presumably high levels of organic solvent exposure. Conversely, paternal pesticide exposure was significantly associated with an increased implantation rate. Paternal exposures to metal dust or fumes and welding fumes were not related to the probability of implantation. CONCLUSION(S): The findings suggested that paternal organic solvent exposure decreased the implantation rate among couples undergoing IVF-ET treatment.

Adult↗
PubMed2000

Performance of population specific job exposure matrices (JEMs): European collaborative analyses on occupational risk factors for chronic obstructive pulmonary disease with job exposure matrices (ECOJEM).

OBJECTIVES: To compare the performance of population specific job exposure matrices (JEMs) and self reported occupational exposure with data on exposure and lung function from three European general populations. METHODS: Self reported occupational exposure (yes or no) and present occupation were recorded in the three general population surveys conducted in France, The Netherlands, and Norway. Analysis was performed on subjects, aged 25-64, who provided good forced expiratory volume in 1 second (FEV1) tracings and whose occupations were performed by at least two people, in the French (6217 men and 5571 women), the Dutch (men from urban (854) and rural (780) areas), and the Norwegian (395 men) surveys. Two population specific JEMs, based on the percentage of subjects who reported themselves exposed in each job, were constructed for each survey and each sex. The first matrix classified jobs into three categories of exposure according to the proportion of subjects who reported themselves exposed in each job (P10-50 JEM, low < 10%, moderate 10-49%, high > or = 50%). For the second matrix, a dichotomous variable was constructed to have the same statistical power as the self reported exposure--that is, the exposure prevalence (p) was the same with both exposure assessment methods (Pp JEM). Relations between occupational exposure, as estimated by the two JEMs and self reported exposure, and age, height, city, and smoking adjusted FEV1 score were compared. RESULTS: Significant associations between occupational exposure estimated by the population specific JEM and lung function were found in the French and the rural Dutch surveys, whereas no significant relation was found with self reported exposure. In populations with few subjects in most jobs, exposure cannot be estimated with sufficient precision by a population specific JEM, which may explain the lack of relation in the Norwegian and the Dutch (urban area) surveys. CONCLUSION: The population specific JEM, which was easy to construct and cost little, seemed to perform better than crude self reported exposures, in populations with sufficient numbers of subjects per job.

Adult↗
PubMed2000

Self reported symptoms and inhibition of acetylcholinesterase activity among Kenyan agricultural workers.

OBJECTIVES: This study was part of the East African pesticides project. The general objective was to assess health hazards posed by handling, storage, and use of pesticides, on agricultural estates and small farms with a view to developing strategies for prevention and control of pesticide poisoning. The aim of this paper is to describe the prevalence of symptoms in this population, to relate levels of inhibition to reported symptoms and evaluate at which levels of inhibition symptoms become increased. METHODS: Complete data were available for 256 exposed subjects and 152 controls from four regions in Kenya. A structured questionnaire on symptoms experienced at the time of interview was given to all subjects and controls. Information was also obtained on sex, age, main occupation, and level of education. Symptoms reported during the high exposure period, were initially clustered in broader symptom categories from reference literature on health effects of pesticides that inhibit cholinesterase (organophosphate and carbamate). Prevalence ratios were estimated for symptoms with changes in cholinesterase activity in serum. RESULTS: Symptom prevalence in exposed subjects was higher during the high exposure period than the low exposure period, although these differences were not significant. Interestingly, a clear and significant change in symptoms prevalence was found in the controls with a higher prevalence in the low exposure period. Analysis of the relation between cholinesterase inhibition and symptoms showed that prevalence ratios were significantly > 1 for respiratory, eye, and central nervous system symptoms for workers with > 30% inhibition. Similar results were found for analyses with the actual level of acetylcholinesterase activity. CONCLUSION: The results suggest the presence of a relation between exposure and acetylcholinesterase inhibition, acetylcholinesterase activity, and respiratory, eye, and central nervous system symptoms. Increased symptom prevalence was found at acetylcholinesterase activities generally considered to be non-adverse.

Acetylcholinesterase↗
PubMed2000

Longitudinal changes in bronchial responsiveness associated with swine confinement dust exposure.

STUDY OBJECTIVES: Acute exposure to the air in swine confinement units causes bronchial hyperresponsiveness and inflammation of the airways. This study was performed to assess the longitudinal development of bronchial responsiveness in pig farmers and to establish exposure-response relationships. METHODS: A cohort of 171 pig farmers was followed over a 3-year period. Bronchial responsiveness was assessed by a histamine provocation test. Long-term average exposure to inhalable dust and endotoxin was determined by personal monitoring in summer and winter, using data on farm characteristics and activities. Time-weighted average (TWA) personal exposure to ammonia was measured. Data on farm characteristics were gathered in the same period. RESULTS: Mean increase in responsiveness was 2.52 doubling concentrations of histamine for a 10% decrease in FEV(1) and 1.36 doubling concentrations for a 20% decrease in FEV(1). Long-term average exposure to dust was 2.63 mg/m(3) and to endotoxin was 105 ng/m(3). TWA exposure to ammonia was 1.60 mg/m(3). After adjusting for age and smoking behavior, long-term average exposure to inhalable dust was associated with increases in bronchial responsiveness expressed as steps for provocative concentration causing 10% fall in FEV(1). TWA exposure to ammonia, use of wood shavings as bedding, and automated dry feeding were associated with increases in responsiveness expressed as steps for provocative concentration causing a 20% fall in FEV(1). CONCLUSIONS: Exposure to dust and ammonia in pig farms contributes to chronic inflammation of the airways and should be reduced.

Adult↗
PubMed2000

Comparison of four methods to assess fungal alpha-amylase in flour dust.

The aim of the study was to compare four different immunological methods to analyse fungal alpha-amylase in flour dust samples. Three European research groups have independently developed four immuno assay based methods to measure alpha-amylase in air samples. Three of the methods use polyclonal antibodies and one method uses monoclonal antibodies. Eighty personal samples have been collected during two to three work-shifts in four bakeries. Sampling was performed with PAS-6 inhalable dust samplers and aliquots from each sample were analysed by the three laboratories. The agreement between the four methods was high compared with agreement between immunological methods to measure other allergens in the air, e.g. for rat allergens. For the three methods with polyclonal antibodies the mean differences for individual samples was less than a factor of two. The arithmetic means (AM) of the estimated alpha-amylase exposure were 12.5, 11.3, 8.6 and 25.9ng/m(3) for the respective methods with values ranging from below the detection limit to 192, 215, 207 and 615 ng/m(3). The AM for all samples analysed by the methods with polyclonal antibodies varied by about a factor of 1.5. About one-third of the values were below or at the detection limit for all methods. In a regression analysis the squared correlation coefficients (R(2)) between the methods varied between 0.91 and 0.95 for the log transformed values. For workplace monitoring, results from the methods using polyclonal antibodies will be relatively comparable. High levels of alpha-amylase might differ in absolute numbers with a factor of two or more between the different methods but will anyway be considered as high and should result in preventive actions. On the other hand, this study also shows that despite the relative agreement between methods, there is a clear need for standardization.

Air Pollutants, Occupational↗
PubMed1999

Exposure-response relationships for work-related sensitization in workers exposed to rat urinary allergens: results from a pooled study.

BACKGROUND: Recent studies in a few industries have shown that the likelihood of IgE-mediated sensitization increases with increasing exposure. The shape of the exposure-response relationships and modification by age, sex, and smoking habit has hardly been studied. OBJECTIVE: The purpose of this study was to determine exposure sensitization relationships for rat sensitization and to evaluate the influence of atopy, smoking habits, and sex. METHODS: Data from 3 cross-sectional studies in The Netherlands, the United Kingdom, and Sweden were used and involved 1062 animal laboratory workers. Selection criteria were harmonized, and this resulted in a study population of 650 animal laboratory workers (60.6% female) with less than 4 years of exposure. Air allergen levels were assessed previously and converted on the basis of an interlaboratory allergen analysis comparison. Available sera were analyzed for the presence of specific antibodies against common allergens (house dust mite, cat, dog, and grass and birch pollen) and work-related allergens (rat and mouse urinary proteins). Questionnaire items on work-related respiratory symptoms, hours worked with rats per week, job performed, smoking habits, and sex were used in this analysis RESULTS: The prevalence of work-related sensitization to rat urinary allergens (IgE >0.7 KU/L) was 9.7 % (n = 63). Thirty-six of the sensitized workers had work-related symptoms (asthma or rhinitis). Two hundred forty-eight workers (38.2%) were atopic (defined as specific IgE to 1 of the common allergens). The sensitization rate increased with increasing air allergen exposure. Atopic workers exposed to low levels of allergen had a more than 3-fold increased sensitization risk compared with nonexposed atopic workers. For atopic subjects, the risk increased little with increasing exposure, whereas for nonatopic subjects, a steadily increasing risk was observed. Smoking and sex did not modify the sensitization risk. CONCLUSION: Rat urinary allergen-sensitization risk increased with increasing exposure intensity. Workers who were atopic had a clearly elevated sensitization risk at low allergen exposure levels.

Allergens↗
PubMed1999

Comparison of methods to assess airborne rat and mouse allergen levels. I. Analysis of air samples.

Airborne laboratory-animal allergens can be measured by several methods, but little is known about the effects of important differences in methodology. Therefore, methods used in research projects in The Netherlands, the UK, and Sweden were compared. Seventy-four sets of three parallel inhalable dust samples were taken by a single operator in animal facilities in the three countries, and analyzed in parallel by the three institutes for rat and mouse urinary allergen. Rat-allergen levels measured by RAST inhibition (UK) were 3000 and 1700 times higher than levels measured by enzyme immunoassay (EIA)-sandwich methods with polyclonal rabbit (The Netherlands) or monoclonal mouse (Sweden) antibodies, while the difference between the two EIA-sandwich methods was much smaller: a factor of 2.2. For mouse allergen, an inhibition radioimmunoassay (RIA) with rabbit antimouse antibodies (UK) gave 4.6 and 5.9 times higher concentrations than sandwich EIAs with rabbit polyclonal antibodies (Sweden and The Netherlands), while the difference between the two sandwich EIAs was, on average, 1.6-fold. Thus, although levels of rat and mouse aeroallergens are significantly correlated, the assay type gives large differences in absolute concentrations, and interlaboratory technical differences affect even the same assay type. Conversion factors can aid comparison between studies, and, in the long term, assay standardization is desirable.

Air Pollutants↗