Exposure to second-hand tobacco smoke and respiratory symptoms in non-smoking adults: cross-sectional data from the general population of Telemark, Norway.

BACKGROUND: In Norway, data on the association between second-hand tobacco smoke (SHS) exposure at home and respiratory symptoms in adults are limited. METHODS: We assessed the association between self-reported exposure to SHS and the prevalence of respiratory symptoms among never-smokers aged 16 to 50 years from the general population who were included in a cross-sectional population-based study in Telemark County, Norway. Logistic regression analysis was used to estimate the odds ratios of symptoms among 8850 never-smokers who provided an affirmative response to questions regarding SHS; 504 (5.7%) of these reported that they lived in a home with daily or occasional indoor smoking. RESULTS: Productive cough and nocturnal dyspnoea were statistically associated with daily SHS exposure (ORs 1.5 [95% CI 1.04-2.0] and 1.8 [1.2-2.7], respectively). In analyses stratified by gender, nocturnal dyspnoea was associated with SHS among women (OR 1.8 [1.1-3.1]), but not among men (OR 0.93 [0.49-1.8]). Symptoms were not associated with occasional SHS exposure in the entire group, but infrequent exposure among men only was associated with increased prevalence of chronic cough; (OR 1.6; [1.04-2.6]) and was negatively associated with wheeze; (OR 0.44 [0.21-0.92)]. CONCLUSIONS: Daily SHS exposure in private homes was associated with productive cough and nocturnal dyspnoea. Our results suggest that preventive measures may be needed to reduce the respiratory effects of SHS at home. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02073708 Registered February 27. 2014.

Association of respiratory symptoms and asthma with occupational exposures: findings from a population-based cross-sectional survey in Telemark, Norway.

OBJECTIVES: The aim of this study was to estimate the prevalence of respiratory symptoms and physician-diagnosed asthma and assess the impact of current occupational exposure. DESIGN: Cross-sectional analyses of the prevalence of self-reported respiratory health and association with current occupational exposure in a random sample of the general population in Telemark County, Norway. SETTINGS: In 2013, a self-administered questionnaire was mailed to a random sample of the general population, aged 16-50, in Telemark, Norway. The overall response rate was 33%, comprising 16 099 responders. OUTCOME MEASURES: The prevalence for respiratory symptoms and asthma, and OR of respiratory symptoms and asthma for occupational groups and exposures were calculated. Occupational exposures were assessed using self-reported exposure and an asthma-specific job-exposure matrix (JEM). RESULTS: The prevalence of physician-diagnosed asthma was 11.5%. For the occupational groups, the category with agriculture/fishery workers and craft/related trade workers was associated with wheezing and asthma attack in the past 12 months, showing OR 1.3 (1.1 to 1.6) and 1.9 (1.2 to 2.8), respectively. The group including technicians and associated professionals was also associated with wheezing OR 1.2 (1.0 to 1.3) and asthma attack OR 1.4 (1.1 to 1.9). The JEM data show that exposure to flour was associated with wheezing OR 3.2 (1.4 to 7.3) and woken with dyspnoea OR 3.5 (1.3 to 9.5), whereas exposures to diisocyanates, welding/soldering fumes and exposure to vehicle/motor exhaust were associated with dyspnoea OR 2.9 (1.5 to 5.7), 3.2 (1.6 to 6.4) and 1.4 (1.0 to 1.8), respectively. CONCLUSIONS: The observed prevalence of physician-diagnosed asthma was 11.5%. The 'manual' occupations were associated with respiratory symptoms. Occupational exposure to flour, diisocyanates, welding/soldering fumes and vehicle/motor exhaust was associated with respiratory symptoms in the past 12 months and use of asthma medication. However, prospective data are needed to confirm the observed associations.

Breath-taking jobs: a case-control study of respiratory work disability by occupation in Norway.

BACKGROUND: The current knowledge on respiratory work disability is based on studies that used crude categories of exposure. This may lead to a loss of power, and does not provide sufficient information to allow targeted workplace interventions and follow-up of patients with respiratory symptoms. OBJECTIVES: The aim of this study was to identify occupations and specific exposures associated with respiratory work disability. METHODS: In 2013, a self-administered questionnaire was mailed to a random sample of the general population, aged 16-50, in Telemark County, Norway. We defined respiratory work disability as a positive response to the survey question: 'Have you ever had to change or leave your job because it affected your breathing?' Occupational exposures were assessed using an asthma-specific job-exposure matrix, and comparison of risks was made for cases and a median of 50 controls per case. RESULTS: 247 workers had changed their work because of respiratory symptoms, accounting for 1.7% of the respondents ever employed. The 'breath-taking jobs' were cooks/chefs: adjusted OR 3.6 (95% CI 1.6 to 8.0); welders: 5.2 (2.0 to 14); gardeners: 4.5 (1.3 to 15); sheet metal workers: 5.4 (2.0 to 14); cleaners: 5.0 (2.2 to 11); hairdressers: 6.4 (2.5 to 17); and agricultural labourers: 7.4 (2.5 to 22). Job changes were also associated with a variety of occupational exposures, with some differences between men and women. CONCLUSIONS: Self-report and job-exposure matrix data showed similar findings. For the occupations and exposures associated with job change, preventive measures should be implemented.

Inflammation in induced sputum after aluminium oxide exposure: an experimental chamber study.

INTRODUCTION: Workers in aluminium production are exposed to a complex mixture of particles and gases potentially harmful to the airways, among them aluminium oxide (Al2O3). With the use of an exposure chamber, we aimed to examine the effects of short-term controlled exposure to Al2O3 on lung function and inflammatory markers in healthy volunteers. METHODS: 15 men (age 19-31) were exposed in random order to clean air or Al2O3 particles (3.8-4.0 mg/m(3)) for 2 h including 30 min exercise (stationary bike, 75 W). The permissible exposure level (PEL) for Al2O3 by Occupational Safety and Health Administration, USA, is 5 mg/m(3) time weighted average (TWA). Sham and particle exposures were separated by at least 2 weeks. Spirometry was carried out, and induced sputum and blood samples were collected 48 h before and 4 and 24 h after exposure. RESULTS: Levels of sputum neutrophils (mean (±SEM)) was increased 24 h post-Al2O3 vs pre-Al2O3 exposure (43% (4) vs 31% (4), p=0.01) and the protein level of interleukin (IL)-8 had a 4.8 (0.9)-fold change increase 24 h after exposure (p<0.01). Following Al2O3 exposure, gene signatures in sputum were significantly increased related to several pathways. CONCLUSIONS: The present study suggests that controlled exposure to Al2O3 particles at levels below PEL (TWA) induces airway inflammation in healthy humans marked by elevated neutrophils and elevated IL-8. In addition, increased expression of genes associated with several biological processes was observed in sputum. Interestingly, inhaled Al2O3-induced effects were localised to the airways and not systemic.

Increased bronchial density of CD25+Foxp3+ regulatory T cells in occupational asthma: relationship to current smoking.

To identify activated T cell subset in the asthmatic bronchia, we developed a triple-colour immunohistofluorescence labelling technique on cryo-section to discriminate activated CD4+CD25+ T cells, (effector T cells) from Foxp3+ regulatory T cells (Treg). Additional coexpression of activation and proliferation markers was also examined in situ. Bronchial biopsies were taken from 20 aluminium potroom workers (12 smokers) with asthma (>12% reversibility), 15 non-asthmatic potroom workers (7 smokers) and 10 non-smoking, non-exposed controls. Non-smoking asthmatics had significantly higher subepithelial density of both Tregs, effector T cells, activated (HLA-DR+) CD8+ and activated CD4+ T cells. Moreover, both Tregs, effector T cells and CD8+ T cells proliferated in the non-smoking asthmatics, only. Although smoking asthmatics had no asthma-associated increase in bronchial T cell, both had a significantly increase in effector T cell to Treg ratios. The significantly increased bronchial density of Tregs, effector T cells, proliferative T cells and activated CD8+ T cells in non-smoking asthmatics clearly showed that both the effector T cells and the inhibitory Treg system were activated in asthma.

Pulmonary function and blood gases after gastric bypass and lifestyle intervention: a comparative study.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Impaired lung function associated with obesity improves with weight loss. WHAT THIS STUDY ADDS: This is the first study to compare the effects of obesity surgery and intensive lifestyle intervention on pulmonary function and arterial blood gases. Arterial oxygenation and pulmonary function improved to a greater extent after gastric bypass than after lifestyle intervention. The superiority of surgical treatment might be mediated by greater weight loss after gastric bypass. Impaired lung function associated with obesity improves with weight loss. The effects of obesity surgery and intensive lifestyle intervention on pulmonary function and arterial blood gases have not previously been subjected to comparative examination. In this 1-year non-randomized controlled clinical trial (ClinicalTrials.gov identifier NCT00273104), 139 morbidly obese subjects (19-66 years, mean [standard deviation] body mass index [BMI] 45.1 kg m(-2) [5.6], 107 women) were treated with either Roux-en-Y gastric bypass surgery (n = 76) or intensive lifestyle intervention (n = 63). Mean weight reduction was 30 (8)% and 8 (9)%, respectively. Dynamic and static lung volumes, gas diffusing capacity and arterial blood gases were measured. Compared with lifestyle intervention, surgery resulted in a significantly greater increase in forced vital capacity (mean [95% confidence interval] between-group difference, 7 [4-10]%), forced expiratory volume in 1 s (7 [5-9]%), total lung capacity (5 [1-8]%), vital capacity (7 [4-9]%), functional residual capacity (18 [12-24]%), expiratory reserve volume (48 [30-66]%) and partial pressure of oxygen in arterial blood (0.5 [0.0-1.0] kPa). These associations either disappeared or diminished after adjusting for weight loss. Reduced central adiposity (waist circumference and waist-to-hip ratio) and systemic inflammation (C-reactive protein and adiponectin) had no effect on pulmonary function beyond the effect of reduced general adiposity (BMI). In morbidly obese subjects, gastric bypass surgery is more effective than lifestyle intervention at improving arterial oxygenation and pulmonary function. The effect might be mediated by greater weight loss after surgical treatment.

Exposure to thoracic dust, airway symptoms and lung function in cement production workers.

Cement dust exposure has previously been associated with airway symptoms and ventilatory impairment. The aim of the present study was to examine lung function and airway symptoms among employees in different jobs and at different levels of exposure to thoracic dust in the cement production industry. At the start of a 4-yr prospective cohort study in 2007, exposure to cement dust, symptoms and lung function were recorded cross-sectionally in 4,265 employees in 24 European cement plants. Bronchial exposure was assessed by 2,670 full-shift dust samples with cyclones collecting the thoracic aerosol fraction. A job exposure matrix was constructed by grouping dust concentrations according to job type and plant. Elevated odds ratios for symptoms and airflow limitation (range 1.2-2.6 in the highest quartile), but not for chronic bronchitis, were found in the higher quartiles of exposure compared with the lowest quartile. Forced expiratory volume in 1 s (FEV(1)) showed an exposure-response relationship with a 270-mL deficit of FEV(1) (95% CI 190-300 mL) in the highest compared with the lowest exposure level. The results support the hypothesis that exposure to dust in cement production may lead to respiratory symptoms and airway obstruction.

Occupational exposure to bacterial single cell protein induces inflammation in lung and blood.

Bacterial single cell protein (BSCP) is used as a protein enrichment in livestock and fish feed, and is extracted from dried bacterial mass. In the production of BSCP, workers are exposed to organic dust containing high levels of endotoxins that may induce acute airway inflammation. However, the long term effect on the airways of such exposure is not known, and we have examined inflammatory markers in induced sputum and blood among BSCP exposed workers. We included 21 non-smoking production workers (age 31-42 (range; mean 35)) without respiratory symptoms and 21 healthy non-exposed references (age 21-52 (range; mean 34)). Airborne endotoxin concentrations were measured, and induced sputum samples and blood samples were collected from the workers and non-exposed references. The airborne endotoxin concentration measured in inhaled air during the work shift was 430 EU/m(3) (50-2000) (median (range)). The percentage of neutrophils in induced sputum was 79% (66-93) (median (25th-75th percentiles)) and 31% (25-45) (p < 0.001) for operators and references, respectively. Protein analysis in induced sputum supernatant showed significantly elevated levels of interleukins IL-1beta and IL-12 (p < 0.05), while blood analysis showed significantly elevated levels of PDGF-BB (platelet-derived growth factor-BB) and RANTES (regulated upon activation normally T cell expressed and secreted) (p < 0.05). Workers exposed to BSCP had an airway inflammation characterized by a high level of neutrophils. However, only a few cytokines were elevated in lung and blood, which could imply low inflammatory activity suggestive of possible adaptation mechanisms due to daily exposure to BSCP, or that the inflammation reaction was a dose-related response occurring at higher levels.

Generation and homogeneity of aerosols in a human whole-body inhalation chamber.

INTRODUCTION: A 16 m(3) whole-body exposure chamber for human exposure to aerosols is described. Several modifications of the aerosol generation and distribution system were needed to ensure a stable aerosol concentration in the chamber, especially when a cyclone pre-classifier was used. RESULTS: After these modifications, stable aerosol concentrations of aluminium oxide with a volume median diameter of 5.7 microm, and approximately 3 microm when the cyclone was used, could be achieved after 1 h of aerosol generation. Aerosol concentrations of 1-8 mg m(-3) generated without the cyclone could be maintained for at least 2 h after the aerosol level had stabilized. The temporal variability [coefficient of variation (CV)] of the aerosol concentration was 4-6%, while concentrations <1 mg m(-3) showed greater relative variability. The spatial variability at 3.8 mg m(-3) without a volunteer in the chamber was 4.8%. With a volunteer in the chamber who performed 30 min of ergometric cycling during 2 h of aerosol exposure, the exposure estimated by personal sampling was 15-17% lower than monitored with an optical particle counter. The variability of personally measured exposure was higher than of stationary measurements showing CVs of 10-19%. CONCLUSIONS: These results show that controlled exposure of human volunteers to a range of concentrations can be achieved with good accuracy in this inhalation chamber. The results compare favourably with other chambers described in the literature. Personal sampling showed lower aerosol concentrations than estimated in an empty chamber and the variability was significantly higher than measured stationary.

Quantitative and qualitative assessment of exposure among employees in Norwegian smelters.

OBJECTIVES: To generate a job exposure matrix (JEM) for dust exposure in Norwegian smelters to be used in an epidemiologic study of respiratory diseases and to identify determinants of exposure. METHODS: The arithmetic mean and geometric mean (GM) of 2619 personal dust exposure measurements were applied in constructing the JEM, which was assigned to 2620 employees participating in a respiratory survey including yearly spirometry and a respiratory questionnaire. A qualitative exposure classification was constructed: (i) line operators were those employed full time in the production line, (ii) non-exposed employees were those who did not work in production and (iii) the remainder were classified as non-line operators. RESULTS: In the ferrosilicon alloy and silicon metal production group (FeSi/Si-metal), the median GM of dust exposure was 2.3 mg m(-3) (0.04-5.6) (10-90% percentiles) compared with 1.6 mg m(-3) (0.02-2.3) in the silicomanganese, ferromanganese and ferrochromium production group (SiMn/FeMn/FeCr). Multivariate analyses showed that dust exposure concentration levels decreased significantly with increasing age (FeSi/Si-metal), was significantly lower in females than in males and was significantly higher in current smokers than in never-smokers. Dust exposure concentration levels were also higher in employees reporting previous exposure to dust, fumes and gases than in employees without such previous exposure, though, significant only in the FeSi/Si-metal production group. CONCLUSION: The dust exposure levels of the employees were higher in the FeSi/Si-metal production group than in the SiMn/FeMn/FeCr production group. Age, gender, smoking status and previous exposure were significant determinants of dust exposure and should be evaluated in future analyses of the relationship between health outcomes and dust exposure in this industry.

Decreased lung function among employees at Norwegian smelters.

BACKGROUND: In the smelting industry airborne pollutants are emitted into the workplace atmosphere during the production process. Our aim in this study was to investigate the relationship between production and lung function among employees at Norwegian smelters. METHODS: Spirometry was performed on 3,924 employees, who also completed a standardized questionnaire. The employees were classified by job functions: (i) line operators were employed full-time on the production line, (ii) non-exposed employees did not work in production, and (iii) the remainder of the employees were classified as non-line operators. RESULTS: The mean age of the participants was 38.6 (range 20.0-55.0) years, 88.5% were males. The multivariate analyses showed that, compared to the forced expiratory volume in one second (FEV(1)) in non-exposed employees, the FEV(1) (95% confidence interval) was 87 (33-141) ml and 65 (12-118) ml lower in line and non-line operators, respectively. The prevalence of airflow limitation (FEV(1)/forced vital capacity (FVC) below the 5th percentile of the predicted value) was 4.7% in non-exposed employees, 7.5% in non-line operators and 8.3% in line operators. CONCLUSION: Compared with non-exposed employees, impairment of lung function among employees at Norwegian smelters was significantly related to the job categories of line operator and non-line operator.

Circulating lipopolysaccharides in the blood from "bioprotein" production workers.

BACKGROUND: Workers producing bacterial single-cell protein (BSCP), "bioprotein," are exposed to organic dust containing high levels of endoxins (lipopolysaccharides, LPS). Workers in this industry have complained of episodes of fever, fatigue, chest tightness, skin dryness and rubor. The aim of the present study was to quantify LPS and inflammatory mediators in plasma among the workers and non-exposed control subjects. METHODS: We included eight non-smoking production workers, aged 32-51 (median 38), and eight non-smoking, non-exposed controls, aged 30-51 (median 39). Airborne and plasma endotoxin concentrations were measured, as well as plasma hsCRP and different cytokines, chemokines and metalloproteinases. RESULTS: The workers who did not use personal respiratory protection were exposed to varying airborne levels of endotoxin, 430 (75-15 000) EU/m3 (median, range). The level of plasma LPS was significantly elevated (p = 0.01) among the workers compared to the non-exposed controls. The workers also had elevated levels of MCP-1 (p = 0.02), MIP-1alpha (p = 0.05) and MMP-3 (p = 0.04). IL-6 and hsCRP were also elevated among the exposed group, but not significantly (p = 0.10 and p = 0.07, respectively). CONCLUSIONS: In this study, we detected LPS in plasma of individuals exposed to high levels of LPS at their workplace. This finding is supported by elevated levels of several inflammatory cytokines among the workers, significantly exceeding that of the non-exposed control group. To the best of our knowledge, this is the first time that plasma LPS, together with increased inflammatory markers in plasma, has been detected in an occupational setting.

Production of silicon alloys is associated with respiratory symptoms among employees in Norwegian smelters.

OBJECTIVES: To develop a qualitative exposure classification of employees in Norwegian smelters and to investigate the relationship between respiratory symptoms and occupational exposure using this classification. METHODS: The 3,924 participants completed a standardised questionnaire including questions of respiratory symptoms, familial asthma, allergy, doctor-diagnosed asthma, smoking habits, previous exposure and occupation. The employees were classified according to their current job function: (1) line operators were employed full time on the production line, (2) non-exposed employees did not work in production, (3) the remaining employees were classified as non-line operators. The association between the prevalence of respiratory symptoms and job category was examined using multivariate logistic regression. RESULTS: The mean age of the participants was 38.6 years (standard deviation 9.2 years), 88.5% were males. The odds ratios (OR) (95% confidence intervals in parenthesis) for dyspnoea, cough and phlegm regarding previous exposure compared with no previous exposure were 1.4 (1.1-1.7), 1.4 (1.2-1.8) and 1.3 (1.0-1.7), respectively. The OR in line operators compared with non-exposed employees was 1.2 (0.9-1.7) for dyspnoea, 1.3 (1.0-1.8) for cough and 1.9 (1.4-2.7) for phlegm. The OR for respiratory symptoms was higher in relation to previous exposure than current job function except for phlegm. CONCLUSION: In Norwegian smelters respiratory symptoms appear to be positively related to both current job function and previous exposure. Previous exposure appears to be more important than current job function.

Genetic and environmental effects on exhaled nitric oxide and airway responsiveness in a population-based sample of twins.

Elevated levels of exhaled nitric oxide (eNO) and airway hyperresponsiveness are intermediate phenotypes of asthma. Using population-based data collected from a sample of twins, the present authors estimated the relative contribution of genes, family environment and nonshared environmental influences to variations in eNO and airway responsiveness (AR). In addition, the genetic and environmental sources of covariation between these two asthma-related phenotypes were investigated. The study population comprised a random sample of 377 adult twins identified through the Norwegian Twin Registry. The main outcome variables were eNO and AR to methacholine. Genetic effects accounted for 60% of the variation in eNO. Family environment accounted for 30% of the variation in AR, while nonshared environmental influences explained the remaining variation for both measures. For both eNO and AR, there were significant regression effects for atopy and smoking. The small, but significant association between eNO and AR was primarily explained by genetic factors. Sub-analyses restricted to atopic and nonsmoking twins strengthened the observation. In conclusion, variations in exhaled nitric oxide and airway responsiveness appear to be explained by different genetic and environmental variance structures. Variation in exhaled nitric oxide is explained by genetic and nonshared environmental effects, whereas an environmental model best explains the variation in airway responsiveness. Common genetic effects explain the small but significant association between exhaled nitric oxide and airway responsiveness.

Reduced bronchial CD4+ T-cell density in smokers with occupational asthma.

Cigarette smoking may alter bronchial inflammation in asthma. Multicolour immunohistofluorescent examination on bronchial cryosections was used to examine bronchial inflammatory cell infiltrate in patients with occupational asthma. Monoclonal antibodies to CD3, CD4, CD8, T-cell receptor-delta1, CD68 and human leukocyte antigen-DR were combined to identify T-cell subsets and macrophages in bronchial biopsies from 20 workers with occupational asthma (12 smokers and eight nonsmokers), 15 healthy workers (seven smokers and eight nonsmokers) and 10 nonsmoking, nonexposed controls. The increased subepithelial CD4+ T-cell density in nonsmoking asthmatics was not present in smoking asthmatics, who had the lowest CD4+ T-cell density of all groups. The decreased subepithelial CD4+ and CD8+ T-cell density correlated with a reduction in lung function, as measured by percentage predicted forced expiratory volume in one second, in smoking asthmatics only. Although smoking asthmatics had a significantly increased number of intraepithelial CD8+ T-cells and macrophages compared with nonsmoking asthmatics, the proportion of gammadelta-T-cells was significantly decreased in both asthmatic groups. Smoking asthmatics had a distinctly different distribution of T-cell subsets compared with nonsmoking asthmatics. The accumulation of subepithelial CD4+ T-cells, which was observed in nonsmoking asthmatics, appeared to be inhibited in smoking asthmatics, suggesting a smoking-induced bronchial immune modulation, at least in occupational asthma in the aluminium industry.

Inflammatory markers in bronchoalveolar lavage fluid from human volunteers 2 hours after hydrogen fluoride exposure.

Fluoride has been in focus as a possible causal agent for respiratory symptoms amongst aluminium potroom workers for several decades. Previously, using bronchoalveolar lavage (BAL), we demonstrated airway inflammation in healthy volunteers 24 hours after exposure to hydrogen fluoride (HF). The objective of the present study was to examine early lung responses to HF exposure. Bronchoscopy with BAL was performed 2 hours after the end of 1-hour exposure to HE Significant reductions in the total cell number and the number of neutrophils and lymphocytes were observed in bronchoalveolar portion (BAP), whereas there were no significant changes in the bronchial portion (BP). Significantly decreased concentrations of beta2-MG, IL-6 and total protein were found in both BAP and BP. Additionally, IL-8 was significantly reduced in BP, and ICAM-1 and albumin were present in lower concentrations in BAP. Lung function measurements were not affected by HF exposure. These reported effects are presumably transitory, as many were not present in the airways 24 hours after a similar HF exposure.

The effects of intervention with local electrostatic air cleaners on airborne dust and the health of office employees.

UNLABELLED: The aim of this intervention study was to identify any health improvements in the upper and lower airways of office workers after the installation of local electrostatic air cleaners. Eighty persons with airways symptoms were recruited and randomly assigned to an intervention or control group. Half of the air cleaners had a non-functioning electrostatic unit. Both participants and field researchers were blinded to the group status. Subjective symptoms were recorded using a questionnaire, and indexes calculated for general, irritation and skin symptoms. Objective respiratory health indicators were recorded, with acoustic rhinometry and peak expiratory flow (PEF) meters. In the intervention group there was a decrease in mean dust concentration from 65 to 35 microg/m(3), and a reduction from 57 to 47 microg/m(3) in the control group (P < 0.05 for difference in decline). The reduction was observed for all particles sizes. The irritation and general symptom indices decreased in both groups, but there was no improvement in the intervention group, compared with the control group. Median PEF increased 3 ml/s in the intervention group, and decreased 4 ml/s in the control group. The adjusted odds ratio for an increase above the 70th percentile was 5.7 (95% CI 1.0-32). PRACTICAL IMPLICATIONS: Electrostatic air cleaners can reduce the dust concentration effectively in the office environment. Small, medium and large sized particles can be reduced by approximately 50%, relatively most effectively for the respirable particles. However, the air cleaners tested in this study produced an annoying fan noise. Cleaning efficiency and noise data should be given consideration before installation. This experimental field study suggests that office workers with airways symptoms may benefit from installation of local electrostatic air cleaners.

Airway inflammation in aluminium potroom asthma.

AIMS: To examine whether asthma induced by exposure to aluminium potroom emissions (potroom asthma) is associated with inflammatory changes in the airways. METHODS: Bronchial biopsy specimens from 20 asthmatic workers (8 non-smokers and 12 smokers), 15 healthy workers (8 non-smokers and 7 smokers), and 10 non-exposed controls (all non-smokers) were analysed. Immunohistofluorescent staining was performed to identify mucosal total leucocytes (CD45+ leucocytes), neutrophils, and mast cells. RESULTS: Median RBM thickness was significantly increased in both asthmatic workers (8.2 microm) and healthy workers (7.4 microm) compared to non-exposed controls (6.7 microm). Non-smoking asthmatic workers had significantly increased median density of lamina propria CD45+ leucocytes (1519 cells/mm2 v 660 and 887 cells/mm2) and eosinophils (27 cells/mm2 v 10 and 3 cells/mm2) and significantly increased concentrations of exhaled NO (18.1 ppb v 6.5 and 5.1 ppb) compared to non-smoking healthy workers and non-exposed controls. Leucocyte counts and exhaled NO concentrations varied with smoking habits and fewer leucocytes were observed in asthmatic smokers than in non-smokers Asthmatic smokers had significantly increased numbers of eosinophils in lamina propria compared to non-exposed controls (10 v 3 cells/mm2). Both eosinophilic and non-eosinophilic phenotypes of asthma were recognised in the potroom workers and signs of airway inflammation were also observed in healthy workers. CONCLUSIONS: Airway inflammation is a central feature of potroom asthma and exposure to potroom emissions induces pathological alterations similar to those described in other types of asthma. Cigarette smoking seems to affect the underlying mechanisms involved in asthma, as the cellular composition of airway mucosa appears different in asthmatic smokers and non-smokers.

Lung function 5 yrs after allogeneic bone marrow transplantation conditioned with busulphan and cyclophosphamide.

Long-term data on lung function after bone marrow transplantation (BMT) are inconclusive. Previously, a persistent reduction in gas transfer 1 yr after allogeneic BMT with busulphan and cyclophosphamide conditioning was reported by the current authors. In the present study this reduction was examined to see if it was permanent, transient or progressive. Prospectively, 43 consecutive adult patients with malignant blood disorders undertook lung function measurements prior to BMT, at 3 month intervals during the 1st yr after BMT and finally after 5 yrs. Mean baseline lung function values were >90% predicted. Within the 1st yr after BMT a transient decline in lung volumes and a persistent reduction in gas transfer were observed. After 5 yrs, baseline values were restored for all variables, except in four patients who developed obliterative bronchiolitis. Acute leukaemia and smoking were independently associated with gas transfer reductions at baseline and during the 1st yr after BMT. Allogeneic bone marrow transplantation with busulphan and cyclophosphamide conditioning was associated with a reduction in gas transfer 1 yr after bone marrow transplantation but baseline values were usually restored after 5 yrs. Since recovery may be gradual and slow, an observation period >1 yr is required before drawing conclusions concerning the development of a permanent reduction in lung function after allogeneic bone marrow transplantation conditioned with busulphan and cyclophosphamide.

Respiratory symptoms and airflow limitation in asphalt workers.

BACKGROUND: Asphalt workers are exposed to bitumen fume and vapour, and to exhaust from engines and passing traffic. AIMS: To assess the occurrence of respiratory symptoms and signs of airflow limitations in a group of asphalt workers. METHODS: All 64 asphalt workers and a reference group of 195 outdoor construction workers from the same company participated in a cross-sectional study. Spirometric tests and a questionnaire on respiratory symptoms and smoking habits were administered. Respiratory symptoms and lung function were adjusted for age and smoking. RESULTS: The FEV1/FVC% ratio was significantly lower in the asphalt workers than in the referents. Symptoms of eye irritation, chest tightness, shortness of breath on exertion, chest wheezing, physician diagnosed asthma, and chronic obstructive pulmonary disease (COPD) were all significantly more prevalent among the asphalt workers. CONCLUSION: In asphalt workers there is an increased risk of respiratory symptoms, lung function decline, and COPD compared to other construction workers.