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

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

Increased incidence of respiratory symptoms among female woodworkers exposed to dry wood.

The aim of the present study was to investigate the occurrence of new respiratory symptoms in relation to wood dust exposure in a 6-yr follow-up study. A total of 1,377 woodworkers (1,137 males; 240 females) and 297 reference workers (137 males; 160 females) participated. Data on respiratory symptoms, employment and smoking habits were collected. Wood dust exposure was assessed from baseline dust measurements, and cumulative wood dust exposure was assessed by study-specific job exposure matrices and exposure time. The geometric mean (geometric sd) dust level decreased during the study period from 0.94 (2.1) to 0.60 (1.6) mg.m(-3). Adjusted analysis revealed positive associations for cumulative incidence proportion of chronic bronchitis and daily coughing for female woodworkers versus female reference workers. The cumulative incidence proportion of daily coughing and chronic bronchitis were found to be associated with baseline wood dust exposure in a dose-dependent manner. The odds ratio (95% confidence interval) for daily coughing (with reference to the lowest exposure quartile) was 1.6 (0.6-4.3), 3.2 (0.9-6.8) and 3.8 (1.5-9.7), respectively, in the second and third lowest and the highest quartile. The figures for chronic bronchitis were, accordingly, 2.3 (0.4-14.5), 3.0 (0.5-18.7) and 6.0 (1.2-28.8). In conclusion, female woodworkers in this low exposure cohort showed an increased incidence of coughing and bronchitis, whereas no relations to wood dust exposure were seen for male woodworkers.

Longitudinal lung function decline and wood dust exposure in the furniture industry.

The aim of the present study was to investigate the relationship between change in lung function and cumulative exposure to wood dust. In total, 1,112 woodworkers (927 males, 185 females) and 235 reference workers (104 males, 185 females) participated in a 6-yr longitudinal study. Forced expiratory volume in one second (FEV(1)), forced vital capacity (FVC), height and weight were measured, and questionnaire data on respiratory symptoms, wood dust exposure and smoking habits were collected. Cumulative inhalable wood dust exposure was assessed using a study-specific job exposure matrix and exposure time. The median (range) for cumulative wood dust exposure was 3.75 (0-7.55) mg x year x m(-3). A dose-response relationship between cumulative wood dust exposure and percent annual decrease in FEV(1) was suggested for female workers. This was confirmed in a linear regression model adjusted for confounders, including smoking, height and age. An additional difference of -14.50 mL x yr(-1) and -27.97 mL x yr(-1) was revealed for females exposed to 3.75-4.71 mg x yr x m(-3) or to >4.71 mg x yr x m(-3), respectively, compared with non-/low-exposed females. For females, a positive trend between wood dust exposure and the cumulative incidence proportion of FEV(1)/FVC <70% was suggested. In conclusion, in the present low-exposed cohort, female woodworkers had an accelerated decline in lung function, which may be clinically relevant.

Birth weight and gestational age among children of Danish pharmacy assistants.

STUDY OBJECTIVE: The aim was to investigate whether specific types of work or exposures among pharmacy assistants were correlated with changes in birth weight or gestational age. DESIGN: The study was a nationwide historical cohort with open entry of all female members of the union of pharmacy assistants during 1979 to 1984. PARTICIPANTS: The cohort comprised 4939 pharmacy assistants under 40 years of age. The questionnaire was answered by 93%. MEASUREMENTS AND MAIN RESULTS: Information on birth weight and gestational age was obtained by linkage to the national birth register. Exposure information on type of work and exposure to pharmaceutical and chemical products during pregnancy was self reported. Only small and non-significant differences in birth weight and gestational age were found between the compared groups. Mean birth weight was 50 g above the national mean and gestational age was longer (p less than 0.0005). CONCLUSIONS: Compared to the Danish population, children of pharmacy assistants are at low risk for experiencing low birth weight and preterm birth. Social status and less smoking during pregnancy among pharmacy assistants might explain the slightly greater mean birthweight and gestational age in this sector of the population.

Cross-shift changes in FEV1 in relation to wood dust exposure: the implications of different exposure assessment methods.

BACKGROUND: Exposure-response analyses in occupational studies rely on the ability to distinguish workers with regard to exposures of interest. AIMS: To evaluate different estimates of current average exposure in an exposure-response analysis on dust exposure and cross-shift decline in FEV1 among woodworkers. METHODS: Personal dust samples (n = 2181) as well as data on lung function parameters were available for 1560 woodworkers from 54 furniture industries. The exposure to wood dust for each worker was calculated in eight different ways using individual measurements, group based exposure estimates, a weighted estimate of individual and group based exposure estimates, and predicted values from mixed models. Exposure-response relations on cross-shift changes in FEV1 and exposure estimates were explored. RESULTS: A positive exposure-response relation between average dust exposure and cross-shift FEV1 was shown for non-smokers only and appeared to be most pronounced among pine workers. In general, the highest slope and standard error (SE) was revealed for grouping by a combination of task and factory size, the lowest slope and SE was revealed for estimates based on individual measurements, with the weighted estimate and the predicted values in between. Grouping by quintiles of average exposure for task and factory combinations revealed low slopes and high SE, despite a high contrast. CONCLUSION: For non-smokers, average dust exposure and cross-shift FEV1 were associated in an exposure dependent manner, especially among pine workers. This study confirms the consequences of using different exposure assessment strategies studying exposure-response relations. It is possible to optimise exposure assessment combining information from individual and group based exposure estimates, for instance by applying predicted values from mixed effects models.

Indices of asthma among atopic and non-atopic woodworkers.

AIMS: To investigate the relation between wood dust exposure and different indices of asthma among woodworkers and non-exposed subjects. METHODS: A total of 302 woodworkers and 71 non-exposed subjects answered a respiratory health questionnaire, underwent a non-specific bronchial provocation test using the Yan method, and received a skin prick test with 12 common inhalant allergens. Subgroups performed repeated peak flow monitoring and underwent a reversibility test. A total of 347 dust measurements among 234 woodworkers were performed with passive dust monitors. RESULTS: The overall geometric mean (geometric standard deviation) exposure to inhalable dust was 0.96 (2.02) mg/m3. There was a tendency to increased risk of asthma among atopic woodworkers compared to atopic non-exposed subjects, with ORs between 3.0 (0.8-11.9) (symptomatic BHR) and 1.3 (0.5-4.2) (work related symptoms). In woodworkers, asthma was associated with atopy, with ORs between 7.4 (2.8-19.7) (symptomatic BHR) and 4.2 (2.4-7.7) (asthma symptoms). Asthma was related to dust level, most pronounced for symptomatic BHR among atopics, with OR 22.9 (1.0-523.6) for the highest compared to the lowest dust level. For work related asthma symptoms the association with dust level was seen only for non-atopics. CONCLUSIONS: Wood dust exposure was associated with asthma, despite a low dust level compared to other studies. Atopy was an important effect modifier in the association between asthma and wood dust exposure.

Risk of spontaneous abortion among Danish pharmacy assistants.

A national study of the risk of medically verified spontaneous abortion was conducted among all pharmacy assistants in Denmark. The cohort was defined as 4939 female members of the Association of Danish Pharmacy Technicians between 1979 and 1984, all under the age of 40 years. Data on spontaneous and induced abortions, and births as well, were obtained from the national registers from the same time period. Data on work history and exposure to pharmaceuticals and chemicals were collected from self-administered postal questionnaires in April 1985 with a response rate of 93%. Studies of spontaneous abortion give rise to many methodological problems. In this study data were analyzed in a case-referent model using pharmacy assistants in administration and at the counter as the reference group. Generally, pharmacy assistants are at low risk with respect to spontaneous abortion. However, a few statistically significant results were found, but a decision on their importance must await further research.

Time to pregnancy among Danish pharmacy assistants.

Time to pregnancy was studied as a parameter of couple fertility in a national cohort of all female members (less than 40 years) of the union of pharmacy assistants from 1979 to 1984. A total of 4 924 women were included in the study. Information on time to pregnancy and exposure was obtained by postal questionnaires in April 1985 (response rate 92%). Prolonged time to pregnancy according to occupation in production or a dispensary or in product control, bottling, and packing is presented, unexposed pharmacy assistants being used as referents. It was possible to use time to pregnancy in an occupational setting as 95% of the women were able to state their time to pregnancy and as 90% of all pregnancies were planned. No association was found between type of work or pharmacy and time to pregnancy, but pharmacy assistants exposed to antibiotics had a slightly increased risk of prolonged time to pregnancy.

[Significance of occupational factors for women's fertility and menstrual cycles]. / Arbejdsmiljøfaktorers betydning for kvinders frugtbarhed og menstruationsforhold.

Reduced fertility is frequent, reflected by the fact that 15% of all couples desiring pregnancy try for more than one year without achieving it. Women at work are often exposed to chemical or physical agents, some of which are carcinogenic or teratogenic. Fertility seems to be affected by exposure to lead, mercury, solvents, textile dyes, noise and some pesticides. The purpose of this paper is to summarize the current knowledge of the relations between fertility, menstrual irregularity and occupational exposures. There are still some methodological problems to be solved in relation to fertility. Waiting time to pregnancy seems to be an appropriate measure of fertility. The full distribution of time to pregnancy over months or menstrual cycles should be used in the analysis.

[Asthma, bronchitis and chronic obstructive pulmonary disease in occupational exposure to wood]. / Asthma, bronkitis og kronisk obstruktiv lungesygdom ved erhvervsmaessig udsaettelse for traestøv.

Two million workers worldwide are regularly exposed to wood dust in the work place. In Denmark alone approximately 40,000 workers are employed in the furniture industry where they are exposed to wood dust on a daily basis. This article reviews epidemiological at studies concerning the relationship between wood dust and the development of asthma, chronic obstructive pulmonary disease (COPD) and bronchitis. Fourteen cross-sectional studies and one register-based cohort study form the basis of this review. The conclusion is that despite possible methodological problems there seems to be a relationship between occupational exposure to the types of wood dust used in Denmark and the development of these pulmonary diseases. The results would indicate that further studies are clearly needed in order to study the incidence of these diseases and the relation to the specific types and amount of wood dust.