Brage (Statens arbeidsmiljøinstitutt)
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Could work-related muscle activity explain sex differences in neck pain? A meta-analysis of a pooled dataset
Full text linkObjectives Sustained activity of the upper trapezius muscle during work has been linked to the development of neck pain. Women have higher occurrences of neck pain than men, even in the same occupations. This study aimed to investigate sex-specific associations between upper trapezius muscle activity time-related variables and neck pain using a meta-analysis of pooled data. Methods Seven Scandinavian research institutes provided surface electromyographic (EMG) data on the upper trapezius muscle activity during work and related questionnaire-based data on neck pain severity. EMG and questionnaire data were harmonized and pooled. Associations between upper trapezius muscle activity variables [median muscle activity, frequency of muscular rest periods, and periods with sustained muscle activity (SUMA)] and neck pain severity were investigated separately for women (N=293) and men (N=418) using linear regression analyses. Results In the cross-sectional analyses, women showed significant positive associations between the number of short SUMA periods and negative associations for long SUMA periods in regard to neck pain severity. In the longitudinal analyses, women showed no significant associations. In the cross-sectional analysis for men, one significant positive association was found between median upper trapezius muscle activity and neck pain severity. Conclusions Compared to men, neck pain severity among women appears to be more dependent on upper trapezius muscle activity patterns at work. Therefore, ergonomic and organizational recommendations for work should be sex-specific or adjusted for women to reduce their prevalence of neck pain. Further research is needed to elucidate the underlying mechanisms of these sex differences.publishedVersio
Application of X-ray diffraction with Rietveld refinement to quantify mineral composition including crystalline silica in respirable dust
Full text linkThis study aimed to test the use of Rietveld refinement on respirable aerosol samples to determine the phase of respirable crystalline silica (RCS) and other minerals. The results from the Rietveld refinement were compared to an external standard method and gravimetrical measurements. Laboratory samples consisting of α-quartz, feldspar, and calcite with variable proportions and total mass loadings were made and analyzed using the NIOSH 7500 Silica, Crystalline, by XRD (filter redeposition) method, followed by Rietveld refinement. Field samples of respirable dust, from construction sites working with concrete, brick, and other materials were included. To correct for amorphous content and unidentified phases, an internal standard was added to the field samples, which were treated like laboratory samples. Rietveld refinement was successfully used for quantification of RCS in laboratory and field samples. The method showed comparable results to the NIOSH 7500 method for quartz and remained linear for laboratory samples up to 20 mg. The lowest quantified amounts of quartz in the laboratory samples were 5 µg. The two methods yielded similar results for RCS in field samples with a total mass of up to 15 mg and a quartz content of 1.8 wt% to 11 wt%. A total sample mass of above 0.5 mg was required for optimal quantification of crystalline phases by Rietveld refinement. The method proved useful in determining RCS and other crystalline components in field samples and corrected for interferences even with a complex matrix and high mass loading.Application of X-ray diffraction with Rietveld refinement to quantify mineral composition including crystalline silica in respirable dustpublishedVersio
Benzene exposure and risk of colorectal cancer by anatomical subsite in the Norwegian offshore petroleum workers cohort
Full text linkObjective To investigate the association between low levels of benzene exposure (≤0.879 parts per million [ppm]-years) and risk of colorectal cancer (CRC) including its anatomical subsites. Methods Among 25,347 male workers in the Norwegian Offshore Petroleum Workers (NOPW) cohort with offshore work history (1965–1998), 455 CRC cases were diagnosed 1999–2021. We compared these with a subcohort (n = 2031) drawn from the full cohort. Work histories were linked to a previously developed industry-specific benzene job-exposure matrix (JEM). Cox regression for case-cohort analyses was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC, adjusted for age, body mass index, smoking, alcohol intake, red/processed meat intake, and physical activity. Results Risks of CRC increased with increasing benzene exposure. For all CRC, the HRs (95% CI) for the most exposed [quartile 4] vs. the unexposed were 1.32 (0.96 to 1.81, [0.177–0.879 ppm-years]; p-trend = 0.085) for cumulative, 1.52 (1.11 to 2.07, [17–34 years]; p-trend = 0.032) for duration, and 1.56 (1.15 to 2.12, [0.015–0.046 ppm]; p-trend = 0.005) for average intensity of benzene exposure. For right-sided colon cancer, the association was most evident for exposure duration (HR = 2.25 (1.33 to 3.80), quartile 4 [17–34 years] vs. unexposed; p-trend = 0.007). Sensitivity analyses showed consistent associations. Conclusion This study found positive exposure-response associations between low-level benzene exposure and CRC risk in offshore petroleum workers. These findings add to emerging evidence that benzene can be associated with solid tumours including lung and bladder, which potentially has important occupational and public health implications.Benzene exposure and risk of colorectal cancer by anatomical subsite in the Norwegian offshore petroleum workers cohortpublishedVersio
Alertness after night shifts among workers in the aluminium industry
Full text linkObjective This case-crossover study aimed to evaluate changes in alertness following night shifts among workers in the aluminium industry, and the potential impact of the number of consecutive night shifts and shift length. Methods We estimated alertness on 87 aluminium workers by a 3-minute version of the Psychomotor Vigilance Test (PVT) after both day- and night shifts. Linear mixed models were used for statistical analysis. Results The level of alertness was significantly lower after three and four consecutive night shifts, compared to after a day shift. No significant differences in alertness were observed between three and four consecutive night shifts, nor between periods of three consecutive 8 + 8 + 8-hour versus 8 + 12 + 12-hour night shifts. Conclusions Our findings indicate reduced alertness after three and four consecutive night shifts, compared to after day work. No significant dose-response effect was observed.Alertness after night shifts among workers in the aluminium industrypublishedVersio
Pulmonary hazards of nanoplastic particles: a study using polystyrene in in vitro models of the alveolar and bronchial epithelium
Full text linkBackground Nanoplastics (NPs) are released into the environment through the degradation of plastic objects, leading to human exposure. Due to their small size, concerns have been raised about the potential hazards to the respiratory tract, as ultrafine and nanoparticles are known to penetrate till the alveolar regions of the lungs, potentially impairing their functions. Thus, in the present study, we used model polystyrene nanoparticles doped with the f luorescent metal europium (PS-Eu) to enhance the understanding of NPs hazard and investigate adverse outcomes associated with exposure in human lungs using alveolar (A549) and bronchial (Calu-3) cell models grown in 2D and 3D submerged conditions or quasi air-liquid interface (ALI) conditions (3D). Results Briefly, after in-dept physicochemical characterization of the particles, we assessed their impact on ROS production, cell viability (AlamarBlue and lactate dehydrogenase assays) and barrier integrity (lucifer yellow assay and TEER measurement), finding no negative effects in either model. However, in alveolar cells, particles increased acidic organelle activity. Transmission electron microscopy and Raman microscopy showed, in both models, a dose- and cell-dependent particle uptake with PS-Eu accumulating in numerous and large endo-lysosomes, which, in transwells-grown A549 cells, often contained also lamellar bodies (LBs), organelles involved in surfactants storage and secretion. After extensively quantifying surfactant proteins (SP) in the pellet and supernatant fractions of treated A549 cells, we observed a significant reduction in several members of this family, including surfactant protein B, which is crucial for lamellar body formation and surface tension regulation in the lungs. In quasi-ALI Calu-3 cultures instead, PS-Eu significantly upregulated interleukin 6 (IL-6) and increased transforming growth factor beta β (TGF-β), zonula occludens 1 (ZO-1), and mucin (MUC) 5B mRNA expressions causing a moderate proinflammatory response. Conclusion Our results show that PS-Eu exposure does not induce acute cytotoxicity in these models, but affects cell-specific functions like surfactant, mucin, and cytokine production. This underscores the limitations of relying solely on standard cytotoxicity tests for particle hazard assessment and highlights the importance of investigatingPulmonary hazards of nanoplastic particles: a study using polystyrene in in vitro models of the alveolar and bronchial epitheliumpublishedVersio
Night shift work and indicators of cardiovascular risk. A systematic review and meta-analysis
Full text linkCardiovascular disease (CVD) is a leading cause of death worldwide, and shift workers have an increased risk of CVD. This comprehensive systematic review and meta-analysis aimed to assess the association between night shift work and cardiovascular risk indicators. A systematic literature search was performed according to the PRISMA 2020 guidelines using Medline, Embase, and Web of Science databases from inception through May 2024. Original manuscripts reporting relevant cardiovascular risk indicators and biomarkers in night shift workers were included. Risk of bias was assessed using the JBI's critical appraisal tools. When applicable, random-effect meta-analyses were performed. If suitable data were not available, a narrative synthesis was performed by combining p-values or vote-counting. Meta-regression analyses were performed to assess the contribution of sex, body mass index, and age as possible modifiers of effect. Evidence was weighed using an adapted GRADE. This study is registered in PROSPERO (CRD42022337285). Of the 8,387 studies identified, 81 were included in the synthesis, comprising 14 cohort and 67 cross-sectional studies. Moderate-confidence evidence was presented demonstrating increased inflammation, dyslipidaemia and impaired cardiac excitability among night shift workers. Dose-dependent effects were reported for these cardiovascular risk indicators, suggesting that the intensity and duration of night shift work contribute to risk of CVD. Furthermore, no association between night shift work and indicators of vascular dysfunction, deregulation of the autonomic nervous system, or altered homeostasis was observed. Considering this, regulatory and preventative initiatives are essential to reduce the cardiovascular risk among night shift workers.publishedVersio
Mapping and estimation of workers’ exposure to substances of very high concern (SVHC) in the Nordic countries
Full text linkThis project aimed to map the use of SVHC, listed in the REACH candidate list (CL), by professional workers, i.e., those using the substances/mixtures containing the substance in their professional undertaking and not in industrial installations. The primary objective was to provide new knowledge regarding the sectors of use and quantity of SVHCs among professional workers in the Nordic countries. Thereby, this project lays a foundation for further work on prevention of exposure of workers to SVHC, chemical risk assessment of these substances, and sector prioritisation for regulatory follow-up. It will also create a basis for informed measures on reduction of prevalence of occupational health challenges due to exposure to SVHC.publishedVersio
Migraine and insufficient sleep: The effect of sleep restriction on nociceptive evoked potentials in migraine
Full text linkBackground The association between insufficient sleep and migraine is largely unexplained. In this blinded cross-over study we investigate whether insufficient sleep disturbs processing of nociceptive signals more in individuals with migraine compared to those without migraine. Methods Evoked potentials to nociceptive laser stimuli and high density electrical dermal stimuli were recorded in migraine and control subjects after two nights of habitual sleep and after two nights of sleep restriction (4 h sleep/night). Researchers conducting the measurements and data processing were blinded to diagnosis and sleep condition. Both recordings were interictal in 21 migraine subjects. Amplitudes, amplitude habituation and latencies were compared to measurements in 31 controls. Results Electrically induced N2P2 amplitude showed more habituation after sleep restriction compared to habitual sleep in the migraine group (p < 0.025). The migraine group also had less N2P2 amplitude habituation after habitual sleep compared to the control group (p < 0.035). We found no effect of sleep restriction on N2P2 amplitude habituation to laser stimulation, and no effect of sleep restriction on N2P2 amplitudes. Conclusion Insufficient sleep may slightly increase cortical inhibitory responses in migraine. Our findings support that migraine is associated with a vulnerability for insufficient sleep between attacks.publishedVersio
Impact of cold exposure on shift working seafood handlers in Northern Norway: a comparative analysis across work shifts
Full text linkObjective This study aimed to investigate the impact of occupational thermal exposure on shift workers, specifically whether cold exposure elicits distinct physiological responses and thermoregulatory recovery across different tasks and shift types. Methods Observational study at two factories processing prawns in Northern Norway in which 32 shift-working seafood handlers with different task responsibilities were followed for a single shift (morning, evening, night). The participants answered questionnaires regarding thermal exposures at work and related symptoms; these were compared to answers from 12 administration workers. Personal thermal loggers measured the range of temperature exposures associated with four different seafood handler work tasks. Pre- and post-shift plasma levels of FGF21, GDF15 and cytokines were analysed using immunoassays. As a proxy for thermoregulatory response across different shift types, hand temperature was measured repeatedly before and after breaks using a thermal imaging camera. Results Most seafood handlers reported subjective impact from cold exposure. Cold working conditions of ≤ 10 ℃ were measured across all shifts and three different seafood handling tasks. The morning shift—seafood handlers displayed lower plasma FGF21 post-shift vs. pre-shift; the evening and night shifts showed no difference. GDF15 levels remained unchanged regardless of shift types but were positively correlated with age. Night shift was associated with increased plasma IL6 post-shift vs. pre-shift. Thermoregulatory responses showed a positive linear relationship with break duration but did not differ between shifts. Conclusions The findings suggest that exposure levels are closely linked to specific tasks and shifts, with thermoregulatory responses varying by task type and time of day.Impact of cold exposure on shift working seafood handlers in Northern Norway: a comparative analysis across work shiftspublishedVersio
Mapping dynamic working life patterns and the impact of occupational exposures. A scoping review
Full text linkBackground An ageing population and increasing life expectancy has intensified pressure to prolong working lives among high-income countries. Emerging research has sought to characterise dynamic working life patterns (how labour market participation changes over the working career), and how various factors, including occupational exposures, influence these patterns. This scoping review aims to systematically map the literature in this area and to identify future research needs. Methods A systematic search was carried out in PubMed, Embase, Web of Science and Scopus. Original studies were included if they included individuals from the general working-age population (defined as 18–70 years of age) or from patient-, sector-, industry-, or occupation-specific populations, and if they examined associations between at least one occupational exposure and a measure of dynamic working life patterns, grouped into either labour market participation trajectories or cumulative time spent in various labour market states. Studies were considered too heterogeneous to allow for quantitative synthesizing of results or calculation of an average measure of working life patterns across studies by exposure. Results The seventeen included original studies were heterogenous with regards to study populations, analysis methods, occupational exposures, and outcomes. Studies of biomechanical and psychosocial exposures were the most common, with indications that biomechanical factors are associated with reduced work participation. Conclusions Future studies would benefit from clearer definitions of occupational exposures and measures of dynamic working life patterns, a broader inclusion of occupational exposures, and measures of cumulative exposure.Mapping dynamic working life patterns and the impact of occupational exposures. A scoping reviewpublishedVersio