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Objectives: The risk of developing hand-arm vibration syndrome (HAVS) from occupational hand-arm vibration (HAV) exposure is traditionally determined by the onset of vascular symptoms (white fingers). However, changes in tactile sensibility at the fingertips is a clinical sign of HAVS which in most cases precedes vascular signs. We aimed to assess relationships between occupational HAV exposure and HAVS-related signs including vibration perception thresholds (VPT) and pegboard score on an individual level, using a longitudinal study design with follow-up tests., Methods: We followed-up 148 workers exposed to different HAV levels for 4 years, with health examinations including VPT tests and pegboard tests carried out at baseline, 2 years and 4 years. VPT testing included seven frequencies, from 8 to 500 Hz. Second and fifth finger on both hands were tested, thus a total of 28 tests on each subject. We investigated associations using linear mixed models and significance level at p≤0.05., Results: There was a significant exposure-response relationship on an individual level between HAV exposure from rock drills and VPT for 16 of 28 test frequencies. The highest rise (worsening) in VPT was found at the 500 Hz test frequency with 1.54 dB increased VPT per 10-fold increase in cumulative exposure. We found no deterioration in pegboard performance associated with HAV exposure among the participants., Conclusions: Risk predictions of HAVS may be based on exposure-response relationships between HAV exposure and VPT. The 500 Hz test frequency should be included in the VPT test protocols for early detection of signs related to reduced tactile sensibility., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Chronic obstructive pulmonary disease and silicosis are associated with exposure to crystalline silica. We determined the exposure to respirable crystalline silica and estimated exposure-response relationships between cumulative exposure and pulmonary function in outdoor rock drillers., Methods: 136 rock drillers and 48 referents were recruited from three heavy construction companies. 98 air samples were collected by personal sampling for determination of respirable particulate matter and crystalline silica. Information about individual job tasks, type of drilling equipment and years of exposure in different job categories was obtained by interview. Cumulative exposure to crystalline silica was calculated for all workers. Pulmonary function was assessed by spirometry. A subgroup of 39 subjects with high cumulative exposure to crystalline silica underwent high-resolution computed tomography (HRCT)., Results: Cumulative exposure (mean (min-max)) to crystalline silica was 0.69 mg٠years m -3 (0.01-5.89) in the exposed group. Mean time of exposure among rock drillers was 10.7 years (1-42). Compared with referents, the rock drillers had a lower forced expiratory volume in one second/forced vital capacity ratio (79.4 vs 81.4, p<0.05) and maximal mid-expiratory flow% (85.6 vs 93.9, p<0.05). Further, by stratifying the exposed workers into three equally large groups, a dose-response relationship was demonstrated in the highest exposed group, also in never smokers, at a mean cumulative exposure of 21.7 years at 0.08 mg٠m -3 /years. Silicosis was not detected in HRCT, but other patterns of fibrosis and emphysema were seen., Conclusions: Outdoor rock drillers exposed to crystalline silica had significantly lower pulmonary function than referents, and signs of airflow obstruction. Silicosis was not detected., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Testing of vibration perception threshold (VPT) at the fingertips as a quantitative measure of tactile sensitivity is a commonly used tool in diagnosing hand-arm vibration syndrome. There is limited research on dose-response relationships between hand-arm vibration (HAV) exposure and VPT on an individual level., Aims: Assess possible dose-response relationships on an individual level between HAV exposure and VPT at the fingertips., Methods: We assessed average daily vibration exposure (m/s 2 A8) and cumulative lifetime HAV exposure for 104 participants from different departments in a road maintenance company based on vibration measurements and questionnaires. VPT was measured based on the technical method described in ISO 13091-1:2005 using octave frequencies 8-500 Hz. We investigated associations using linear regression models with significance level p≤0.05., Results: The participants were either exposed to rock drills (n=33), impact wrenches (n=52) or none of these tools (n=19). Exposure to rock drills and impact wrenches was associated with elevated VPT for all seven test frequencies in the second and fifth fingers of both hands. A dose-response with the daily exposure measure m/s 2 (A8) was found based on 1.2 m/s 2 (A8) for impact wrenches, and 5.4 m/s 2 (A8) for rock drills. A stronger association was found with the cumulative exposure for rock drills compared with impact wrenches, and for the second finger compared with the fifth finger., Conclusions: HAV exposure was associated with elevated VPT, also at exposure levels below the common exposure action value of 2.5 m/s 2 (A8). Lowering the HAV exposure can contribute to prevent increasing VPTs in these workers., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: This study aimed to assess the biological impact of occupational exposure to diesel exhaust (DE) including DE particles (DEP) from heavy-duty diesel-powered equipment in Norwegian tunnel finishing workers (TFW)., Methods: TFW (n=69) and referents (n=69) were investigated for bulky DNA adducts (by 32 P-postlabelling) and expression of microRNAs (miRNAs) (by small RNA sequencing) in peripheral blood mononuclear cells (PBMC), as well as circulating free arachidonic acid (AA) and eicosanoid profiles in plasma (by liquid chromatography-tandem mass spectrometry)., Results: PBMC from TFW showed significantly higher levels of DNA adducts compared with referents. Levels of DNA adducts were also related to smoking habits. Seventeen miRNAs were significantly deregulated in TFW. Several of these miRNAs are related to carcinogenesis, apoptosis and antioxidant effects. Analysis of putative miRNA-gene targets revealed deregulation of pathways associated with cancer, alterations in lipid molecules, steroid biosynthesis and cell cycle. Plasma profiles showed higher levels of free AA and 15-hydroxyeicosatetraenoic acid, and lower levels of prostaglandin D 2 and 9-hydroxyoctadecadienoic acid in TFW compared with referents., Conclusion: Occupational exposure to DE/DEP is associated with biological alterations in TFW potentially affecting lung homoeostasis, carcinogenesis, inflammation status and the cardiovascular system. Of particular importance is the finding that tunnel finishing work is associated with an increased level of DNA adducts formation in PBMC., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Tunnel construction workers are exposed to particulate and gaseous air contaminants. Previous studies carried out in the 1990s showed that tunnel construction workers were at increased risk of both short-term and long-term lung function decline. Since then, efforts have been made to reduce exposure. The objective of the present study was to investigate if current exposure may still cause short-term lung function impairment., Methods: Tunnel workers work 12 days consecutively, and then they are off for 9 days. Ninety tunnel workers and 51 referents were examined with spirometry and questionnaires before their work period started and again 11 days later. Personal exposure to particles and α-quartz in the thoracic aerosol subfraction, elemental carbon and organic carbon, oil mist, nitrogen dioxide and ammonia was assessed on two consecutive days between the two health examinations., Results: The geometric means air concentrations for particulate matter in the thoracic mass aerosol subfraction, α-quartz, oil mist, organic carbon and elemental carbon for all workers were 561, 63, 210, 146 and 35 μg/m(3), respectively. After 11 days of work, the mean forced expiratory volume in 1 s (FEV1) in healthy participants had declined 73 mL (SD 173), p<0.001 in the tunnel workers, compared to 3 mL (SD 21), p=0.9 in the referents. Also, forced vital capacity (FVC) had declined significantly. Declines in FVC and FEV1 were significantly associated with exposure to organic carbon., Conclusions: In spite of reduced levels of exposure in modern tunnelling operations, a negative impact on lung function was still observed., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

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.

Aims: To study the relation between lung function decrease and cumulative exposure to dust and gases in tunnel construction workers., Methods: A total of 651 male construction workers (drill and blast workers, tunnel concrete workers, shotcreting operators, and tunnel boring machine workers) were followed up by spirometric measurements in 1989-2002 for an average of six years. Outdoor concrete workers, foremen, and engineers served as a low exposed referent population., Results: The between worker component of variability was considerably reduced within the job groups compared to the whole population, suggesting that the workers within job groups had similar exposure levels. The annual decrease in FEV1 in low-exposed non-smoking workers was 21 ml and 24 ml in low-exposed ever smokers. The annual decrease in FEV1 in tunnel construction workers was 20-31 ml higher than the low exposed workers depending on job group for both non-smokers and ever smokers. After adjustment for age and observation time, cumulative exposure to nitrogen dioxide showed the strongest association with a decrease in FEV1 in both non-smokers, and ever smokers., Conclusion: Cumulative exposure to nitrogen dioxide appeared to be a major risk factor for lung function decreases in these tunnel construction workers, although other agents may have contributed to the observed effect. Contact with blasting fumes should be avoided, diesel exhaust emissions should be reduced, and respiratory devices should be used to protect workers against dust and nitrogen dioxide exposure.

Objectives: To see if there is any change in blood concentrations of interleukin-6 (IL-6) and fibrinogen during a working shift in tunnel construction workers., Methods: 12 Tunnel construction workers were followed up during a 24 hours period after returning from a 9 day work free period. The first blood sample was taken on Monday afternoon before starting the shift. Another was taken around midnight after 8 hours of work, and another the next afternoon after about 12 hours of rest. Exposure to respirable dust was measured by personal samplers., Results: The exposure of the workers to respirable dust, in terms of an 8 hour time weighted average, varied between 0.3 and 1.9 mg/m(3). For IL-6, there was an increase in the median serum concentration from 1.14 ng/l before starting the shift to 4.86 ng/l after 8 hours of work (p=0.002). For fibrinogen, there was an increase in the median concentration from 3.40 g/l before entering the shift to 3.70 g/l 24 hours later (p=0.044). There was a positive correlation between values of IL-6 at the end of the working shift and the fibrinogen concentrations the next afternoon (Pearson's R=0.73, p=0.007). The observed increase in IL-6 was significant for both smokers and non-smokers., Conclusion: The study shows an increase in both IL-6 and fibrinogen concentrations during a working shift for both smoking and non-smoking tunnel construction workers.

Objectives: To examine whether underground construction workers exposed to tunnelling pollutants over a follow up period of 8 years have an increased risk of decline in lung function and respiratory symptoms compared with reference subjects working outside the tunnel atmosphere, and relate the findings to job groups and cumulative exposure to dust and gases., Methods: 96 Tunnel workers and a reference group of 249 other heavy construction workers were examined in 1991 and re-examined in 1999. Exposure measurements were carried out to estimate personal cumulative exposure to total dust, respirable dust, alpha-quartz, oil mist, and nitrogen dioxide. The subjects answered a questionnaire on respiratory symptoms and smoking habits, performed spirometry, and had chest radiographs taken. Radiological signs of silicosis were evaluated (International Labour Organisation (ILO) classification). Atopy was determined by a multiple radioallergosorbent test (RAST)., Results: The mean exposure to respirable dust and alpha-quartz in tunnel workers varied from 1.2-3.6 mg/m3 (respirable dust) and 0.019-0.044 mg/m3 (alpha-quartz) depending on job task performed. Decrease in forced expiratory volume in 1 second (FEV1) was associated with cumulative exposure to respirable dust (p<0.001) and alpha-quartz (p=0.02). The multiple regression model predicted that in a worker 40 years of age, the annual decrease in FEV1 would be 25 ml in a non-exposed non-smoker, 35 ml in a non-exposed smoker, and 50-63 ml in a non-smoking tunnel worker (depending on job). Compared with the reference group the odds ratio for the occurrence of new respiratory symptoms during the follow up period was increased in the tunnel workers and associated with cumulative exposure to respirable dust., Conclusions: Cumulative exposures to respirable dust and alpha-quartz are the most important risk factors for airflow limitation in underground heavy construction workers, and cumulative exposure to respirable dust is the most important risk factor for respiratory symptoms. The finding of accelerated decline in lung function in tunnel workers suggests that better control of exposures is needed.