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.

Organic dust-related respiratory and eye irritation in Norwegian farmers.

BACKGROUND: Information on exposure to organic dust and work-related symptoms in farmers is sparse. METHODS: An exposure study was nested in a survey of 8,482 farmers and spouses. Task-related respiratory and eye symptoms were recorded by questionnaire. Personal exposure to total dust, fungal spores, bacteria, endotoxins, and ammonia during 12 different tasks was measured in a random sample of 127 farms (288 measurements). RESULTS: The prevalence of work-related symptoms occurring "often" was 31% and "seldom" 35%. Specific tasks provoking symptoms were reported by 5-55% of the farmers. Task mean exposures ranged from 0.04 to 2 mg dust/m(3), 0.02 x 10(6) to 2 x 10(6) fungal spores/m(3), 0.2 x 10(6) to 48 x 10(6) bacteria/m(3), 0.5 x 10(3) to 28 x 10(3) endotoxin units/m(3), and 0 to 8 ppm ammonia. Task mean exposure levels were positively correlated with task-specific symptom prevalences for total dust, fungal spores, and endotoxins but not for bacteria and ammonia. CONCLUSION: Work-related symptoms are common in farmers and are associated with exposure to total dust, fungal spores, and endotoxins.

Serum eosinophil cationic protein in asthma of farmers.

OBJECTIVE: There is need for relevant markers of bronchial inflammation in epidemiologic studies of asthma. Serum eosinophil cationic protein (ECP) is a marker of eosinophil inflammation and asthma activity. We have studied serum ECP in atopic farmers with current asthma, in non-atopic asthmatics and in non-asthmatic, non-atopic controls. METHODS AND RESULTS: In a cross-sectional study of a representative sample of 8,482 farmers in Norway, asthma was recorded using a self-administered questionnaire; spirometry and serum sampling were performed on all of them. Atopy was screened with Phadiatop and RAST analyses to the mites Lepidoglyphus destructor and Tyrophagus putrescentiae in all asthma cases and controls. All the identified atopics had additional RAST analyses on a set of allergens. Serum ECP was tested in 60 persons with current asthma and atopy (mean 16.2, 95% CI 13.2-19.3), 127 non-atopic asthmatics (mean 9.1, 95% CI 8.0-10.2) and 39 non-atopic controls (mean 5.5, 95% CI 4.0 7.0). ECP levels in atopic asthmatics were associated with number of positive allergens and reduction of FEVI values. Moreover, the ECP levels were elevated with allergy to swine, cow, D. pteronyssinus, L. destructor, A. siro, T. putrescentiae, timothy grass and the cereal grains: wheat, oat, barley and rye. CONCLUSION: Serum ECP seems feasible as an indicator of inflammatory activity in epidemiological studies of current allergic asthma, and may help to indicate the importance of specific allergens. Although the ECP values were significantly more elevated in atopic than in non-atopic asthma, elevated serum ECP was not specific for atopic asthma.

Increased risk of obstructive pulmonary disease in tunnel workers.

BACKGROUND: Tunnel workers are exposed to gases and particles from blasting and diesel exhausts. The aim of this study was to assess the occurrence of respiratory symptoms and airflow limitation in tunnel workers and to relate these findings to years of exposure. METHODS: Two hundred and twelve tunnel workers and a reference group of 205 other heavy construction workers participated in a cross sectional investigation. Exposure measurements were carried out to demonstrate the difference in exposure between the two occupational groups. Spirometric tests and a questionnaire on respiratory symptoms and smoking habits were applied. Atopy was determined by a multiple radioallergosorbent test (RAST). Radiological signs of silicosis were evaluated. Respiratory symptoms and lung function were studied in relation to years of exposure and adjusted for smoking habits and atopy. RESULTS: Compared with the reference subjects the tunnel workers had a significant decrease in forced vital capacity (FVC) % predicted and forced expiratory volume in one second (FEV(1)) % predicted when related to years of exposure. Adjusted FEV(1) decreased by 17 ml for each year of tunnel work exposure compared with 0.5 ml in outdoor heavy construction workers. The tunnel workers also reported significantly higher occurrence of respiratory symptoms. The prevalence of chronic obstructive pulmonary disease (COPD) was 14% in the tunnel workers compared with 8% in the reference subjects. CONCLUSION: Exposure to dust and gases from diesel exhaust, blasting, drilling and rock transport in tunnel work enhances the risk for accelerated decline in FEV(1), respiratory symptoms, and COPD in tunnel workers compared with other heavy construction workers.

Asthma in tunnel workers exposed to synthetic resins.

OBJECTIVES: The prevalence of asthma among tunnel workers exposed to synthetic resins was studied by determining airway symptoms, methacholine responsiveness, and lung function. METHODS: Nineteen injection workers were compared with a group of 104 other tunnel workers with similar exposure, except for that to synthetic resins. A questionnaire on respiratory symptoms, smoking habits, use of respiratory protection, and work tasks was used. Lung function was studied using a bellows spirometer. Bronchial reactivity was tested with methacholine. Allergy screening with Phadiatop and radioallergosorbent tests for toluene-diisocyanate-HSA, diphenylmethane-4.4-diisocyanate-HSA, and formaldehyde-HSA (HSA = human serum albumin) were carried out. Methylene diphenyl diisocyanate (MDI) and MDI prepolymer exposure was estimated by filter sampling, and the filters were analyzed by high-performance liquid chromatography. The most common work situations were simulated for an estimation of exposure to isocyanates. RESULTS: The injection workers reported more respiratory symptoms than the reference group, and they had higher prevalences of bronchial hyperresponsiveness (37% versus 14%), asthma (26% versus 1%), and airflow limitation (37% versus 4%). Toluene-diisocyanate-HSA-specific immunoglobulin E antibodies were found in 2 of the 19 injection workers, but in none of the other tunnel workers. By simulation at a worksite, the average exposure to polymerized MDI was estimated to be 5.5-300 microg/m3 during injection work and 18-4300 microg/m3 during short-term exposure, the highest exposure occurring when cured polyurethane was ground. CONCLUSIONS: Exposure to partly decomposed MDI in tunnel work enhances the risk for respiratory symptoms, methacholine hyperresponsiveness, asthma, and airflow limitation.

Determinants of asthma in a farming population.

OBJECTIVES: This study examined the determinants of asthma in a population of farmers, including as a crude indicator of genetic predisposition "history of asthma in next-of-kin" (family history), and exposure factors such as animal production and smoking. METHODS: In a cross-sectional study of 8482 farmers or farmers' spouses in Norway a questionnaire with information on asthma among the subjects and their next-of-kin, production type and farming activities, exposures outside farming, and smoking was applied. Spirometry was performed. RESULTS: The lifetime prevalence of self-reported asthma in the population was 6.3%. Significant risk factors for current asthma were asthma among next-of-kin, asthma as child or adolescent, animal production, and age. In a comparison with subjects with no family history of asthma and no animal production the adjusted odds ratio for current asthma in never smokers was 1.9 [95% confidence interval (95% CI) 0.4-8.9] for subjects with family history only, 2.2 (95% CI 1.1-4.2) for subjects with animal production only, and 6.3 (95% CI 3.1-13.1) for subjects with both factors. A combination of animal production, smoking, and a positive family history gave an odds ratio of 8.1 (95% CI 4.0-16.2) for current asthma. CONCLUSIONS: The study can be interpreted as support for the hypothesis of an interaction between genetic factors and exposure factors in the causation of asthma. Since familial associations may be exposure-related, the necessity of considering indicators of both inheritance and exposure in epidemiologic studies of asthma is emphasized.

Chronic bronchitis in farmers.

OBJECTIVES: Chronic bronchitis was studied in relation to work time and years of exposure in farming, as well as to production type, dusty occupation outside farming, and the combination of work exposure and smoking, in a population of farmers. METHODS: In 1989 a representative cohort of 10,792 farmers and spouses was selected from a government register and invited to participate in a cross-sectional study in 1991. The total response rate was 80%. There were 33% part-time farmers, and among the men 32% of the full-time and 42% of the part-time farmers had worked in dusty occupations outside farming. Bronchitis symptoms were recorded on a self-administered questionnaire, spirometric data were obtained, and internal reference equations were calculated for forced expiratory volume in 1 s (FEV1.0). RESULTS: The exposure factors of importance for chronic bronchitis were full-time farming versus part-time farming, livestock production types (poultry, dairy, swine, horse and combinations), and occupational dust exposure outside agriculture. The combinations of the work exposure factors were significant and showed a 2- to 3-fold increase in risk for chronic bronchitis. Combinations with smoking showed up to a 6-fold increase in risk. Over the age of 50 years, chronic bronchitis was a risk factor for airway obstruction defined as the standardized residuals for FEV1.0 less than -2 for both nonsmokers (OR 2.8, 95% CI 1.1-6.8) and smokers (OR 8.5, 95% CI 5.1-14.3). CONCLUSIONS: Work exposure factors in farming and other dusty occupations enhance the risk for chronic bronchitis from 2- to 3-fold for farmers. In combination with smoking the risk increases to up to 6-fold.

Divers' pulmonary function after open-sea bounce dives to 10 and 50 meters.

We have studied pulmonary function before and 2 h after open sea dives to 10 and 50 m and 24 h after the dive to 10 m. Nine trainee divers participated in the dive to 10 m and 17 in the dive to 50 m. Mean time in water was 53 (32-62) min for the 10-m dive and 38 (26-76) min for the 50-m dive. Assessment of lung function included dynamic lung volumes and flows and transfer factor for carbon monoxide (TlCO). There were significant reductions (P < 0.05) in forced vital capacity of 5.8% (SD = 3.9) and 1.8% (SD = 2.8), in forced expired volume in 1 s of 6.6% (SD = 3.5) and 2.7% (SD = 2.4), in forced mid-expiratory flow rate of 10.3% (SD = 7.8) and 5.2% (SD = 6.5), and in TlCO of 11.3% (SD = 7.9) and 12.8% (SD = 5.9) 2 h after the 10- and 50-m dive, respectively. Our results indicate that factors related to submersion and increased breathing resistance contribute to changes in pulmonary function in the first hours after open-sea bounce dives.

[Principles for assessment and diagnosis of work-related pulmonary and pleural diseases]. / Prinsipper for utredning og diagnostikk ved yrkesrelaterte lunge- og pleurasykdommer.

Proposals for diagnostic methods and clinical evaluation of occupational lung and pleural diseases have been worked out by a Working Group appointed by the Norwegian Thoracic Society and the Norwegian Society of Occupational Medicine. The management of this group of diseases demands both an evaluation of occupational exposure and a specific pulmonary diagnosis. Recommendations were made especially for obstructive, interstitial, and malignant diseases.

[Expert statement and assessment of medical impairment in work-related pulmonary disease]. / Spesialisterklaeringen og fastsettelse av medisinsk invaliditet ved yrkesrelaterte lungesykdommer.

The Norwegian Societies of Thoracic Medicine and Occupational Medicine established a working group to standardise diagnostic procedures and evaluation of work-related respiratory disorders. In cases of suspected work-related diseases the physician may be asked by the National Insurance Administration or an insurance company to make a statement which will be one of the documents used to decide the patient's right to compensation benefit. We discuss the role of the physician as an independent expert. This is different from his role as clinician. The statement should include a balanced presentation of information from different sources, including health and occupational history, and the employer's information about the work environment (quantitative and qualitative exposure data). The statement must also include the results of a clinical examination and an assessment of functional status based on objective tests. The paper contains recommendations for evaluation of permanent impairment in light of the present Norwegian laws and regulations.

Exposure to bacterial aerosols and work-related symptoms in sewage workers.

Personal exposure to airborne bacteria and symptoms were studied in 24 sewage workers. An association between levels of total bacteria, rod-shaped bacteria, and symptoms, such as tiredness and headache, during and after work was found.

Folate and vitamin B12 (cobalamin) blood levels in elderly persons in geriatric homes.

Significantly lower mean plasma and whole blood folate levels were noted in elderly persons in geriatric homes as compared to mean values of a reference sample group. The vitamin B12 levels of the elderly persons did not differ significantly from the reference values. More elderly, however, had low B12 values when assayed with a specific binder than when assayed with a non-specific binder. This probably means that B12 analogues are more frequently present in elderly persons in geriatric homes than in subjects in the reference sample group. One half of the disabled elderly persons had low B12 and/or low folate levels as compared to only one fifth of the not disabled elderly persons. Hypersegmentation of neutrophils in peripheral blood was observed in elderly persons who had low levels of B12 as well as of both plasma and whole blood folate. Those with normal values of at least one of these variables did not have hypersegmentation more frequently than those with normal B12 and folate values, implying that isolated low values of either B12 or folate is not synonymous with functional deficiency.