Objective: To perform a systematic review of randomized controlled trials (RCTs) on the efficacy of therapeutic exercises for workers suffering from rotator cuff (RC) tendinopathy. Methods: A literature search in four bibliographical databases (Pubmed, CINAHL, EMBASE, and PEDro) was conducted from inception up to February 2015. RCTs were included if participants were workers suffering from RC tendinopathy, the outcome measures included work-related outcomes, and at least one of the interventions under study included exercises. The methodological quality of the studies was evaluated with the Cochrane Risk of Bias Assessment tool. Results: The mean methodological score of the ten included studies was 54.4%±17.2%. Types of workers included were often not defined, and work-related outcome measures were heterogeneous and often not validated. Three RCTs of moderate methodological quality concluded that exercises were superior to a placebo or no intervention in terms of function and return-to-work outcomes. No significant difference was found between surgery and exercises based on the results of two studies of low to moderate methodological quality. One study of low methodological quality, comparing a workplace-based exercise program focusing on the participants' work demands to an exercise program delivered in a clinical setting, concluded that the work-based intervention was superior in terms of function and return-to-work outcomes. Conclusion: There is low to moderate-grade evidence that therapeutic exercises provided in a clinical setting are an effective modality to treat workers suffering from RC tendinopathy and to promote return-to-work. Further high quality studies comparing different rehabilitation programs including exercises in different settings with defined workers populations are needed to draw firm conclusions on the optimal program to treat workers.
Objective: Working conditions, such as walking and standing on hard surfaces, can increase the development of musculoskeletal complaints. At the interface between flooring and musculoskeletal system, safety shoes may play an important role in the well-being of employees. The aim of this study was to evaluate the effects of different safety shoes on gait and plantar pressure distributions on industrial flooring. Methods: Twenty automotive workers were individually fitted out with three different pairs of safety shoes ( "normal" shoes, cushioned shoes, and midfoot bearing shoes). They walked at a given speed of 1.5 m/s. The CUELA measuring system and shoe insoles were used for gait analysis and plantar pressure measurements, respectively. Statistical analysis was conducted by ANOVA analysis for repeated measures. Results: Walking with cushioned safety shoes or a midfoot bearing safety shoe led to a significant decrease of the average trunk inclination (p<0.005). Furthermore, the average hip flexion angle decreased for cushioned shoes as well as midfoot bearing shoes (p<0.002). The range of motion of the knee joint increased for cushioned shoes. As expected, plantar pressure distributions varied significantly between cushioned or midfoot bearing shoes and shoes without ergonomic components. Conclusion: The overall function of safety shoes is the avoidance of injury in case of an industrial accident, but in addition, safety shoes could be a long-term preventive instrument for maintaining health of the employees' musculoskeletal system, as they are able to affect gait parameters. Further research needs to focus on safety shoes in working situations.
Objective: The purpose of this study was to investigate the effects of Nickel (Ni) -smelting fumes on oncogenic proteins in vivo and in vitro. Methods: Ni fallout beside a Ni smelting furnace in a factory was sampled to study its toxic effect. The effects of Ni-smelting fumes on the regulation of PI3K and ERK signaling pathways and the important downstream hypoxia inducible factor, HIF-1α, were studied both in NIH/3T3 cells and in the lung tissue of rats. NIH/3T3 cell transformation induced by Ni-smelting fumes was also observed. Results: Ni-smelting fumes activated PI3K, p-AKT, p70S6K1, and ERK proteins and increased HIF-1α expression in a time- and dose-dependent manner. However, activation was suppressed when NIH/3T3 cells were pretreated with PI3K/AKT or ERK inhibitors. Ni-smelting fumes caused malignant transformation of NIH/3T3 cells. Conclusions: Ni-smelting fumes increased the expression of HIF-1α through the PI3K/ERK pathway in NIH/3T3 cells and induced malignant transformation in these cells indicating that Ni-smelting fumes may be a potential carcinogen in mammalian cells.
Objectives: This study investigated whether the association between perceived psychological contract breach (PCB) and employee mental health is moderated by the cognitive-motivational pattern of overcommitment (OC). Linking the psychological contract approach to the effort-reward imbalance model, this study examines PCB as an imbalance in employment relationships that acts as a psychosocial stressor in the work environment and is associated with stress reactions that in turn negatively affect mental health. Methods: The analyses were based on a sample of 3,667 employees who participated in a longitudinal linked employer-employee survey representative of large organizations (with at least 500 employees who are subject so social security contributions) in Germany. Fixed-effects regression models, including PCB and OC, were estimated for employee mental health, and interaction effects between PCB and OC were assessed. Results: The multivariate fixed-effects regression analyses showed a significant negative association between PCB and employee mental health. The results also confirmed that OC does indeed significantly increase the negative effect of PCB on mental health and that OC itself has a significant and negative effect on mental health. Conclusions: The results suggest that employees characterized by the cognitive-motivational pattern of OC are at an increased risk of developing poor mental health if they experience PCB compared with employees who are not overly committed to their work. The results of this study support the assumption that psychosocial work stressors play an important role in employee mental health.
Introduction: Hearing impairment remains the main occupational health problem in the manufacturing industry, and its contributing factors have not been well controlled. Methods: Unmatched case control and comparative studies were carried out among fertilizer factory workers in Sarawak with the aim of determining contributing factors for hearing impairment. Respondents consisted of 49 cases that were diagnosed from 2005 to 2008 with 98 controls from the same work places. Chi-square test and Mann-Whitney test were used in a univariate analysis to determine the association between hearing impairment and the contributing risks being studied. Results: The results of the univariate analysis showed that hearing impairment was significantly (p<0.05) associated with older age, lower education level, high smoking dose, high occupational daily noise dose, longer duration of service, infrequent used of hearing protection device (HPD), and low perception of sound on HPD usage. Multivariate logistic regression of hearing impairment after controlling for age found the following five variables: occupational daily noise dose ≥50% (OR 3.48, 95% CI 1.36-8.89), ≥15 years of services (OR 2.92, 95% CI 1.16-7.33), infrequent use of HPD (OR 2.79, 95% CI 1.15-6.77), low perception of sound on HPD (POR 2.77, 95% CI 1.09-6.97), and smoking more than 20 packs per year (OR 4.71, 95% CI 1.13-19.68). Discussion: In conclusion, high occupational noise exposure level, longer duration of service, low perception of sound on HPD, infrequent used of HPD, and smoking more than 20 packs per year were the contributing factors to hearing impairment, and appropriate intervention measures should be proposed and taken into considerations.
Objective: To compare the diagnostic accuracy of two vision screeners by a visual examination performed by an optometrist (gold standard) and to evaluate the concordance between both screeners and between each screener and the gold standard. Methods: This was a cross-sectional study that included computer workers who attended a routine yearly health examination. The study included administrative office workers (n=91) aged 50.2±7.9 years (mean±standard deviation), 69.2% of whom were women and 68.1% of whom used video display terminals (VDT) for >4 h/day. The routine visual examination included monocular and binocular distance visual acuity (VA), distance and near lateral phoria (LP), stereo acuity (SA), and color vision. Tests were repeated with Optec 6500 (by Stereo Optical) and Visiotest (by Essilor) screeners. Sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV), and false positive and negative rates were calculated. Kappa coefficient (κ) was used to measure the concordance of the screeners and the gold standard. Results: The sensitivity and specificity for monocular VA were over 80% for both vision screeners; PPV was below 25%. Sensitivity and specificity were lower for SA (55%-70%), PPV was 50%, and NPV was 75% for both screeners. For distance LP, sensitivity and PPV were <10% in both cases. The screeners differed in their values for near LP: Optec 6500 had higher sensitivity (43.5%), PPV (37.0%), and NPV (79.7%); whereas the Visiotest had higher specificity (83.8%). For color vision, Visiotest showed low sensitivity, low PPV, and high specificity. Visiotest obtained false positive rates that were lower or similar to Optec 6500, and both screeners obtained false negative rates below 50%. Both screeners showed poor concordance (κ<0.40). Conclusions: A high value for NPV would qualify both screeners as acceptable alternatives for visual health surveillance when used as a screening tool; patients with positive test results should be referred to a specialist.
Objectives: Ultraviolet radiation (UVR) emitted during arc welding frequently causes keratoconjunctivitis and erythema in the workplace. The degree of hazard from UVR exposure depends on the welding method and conditions. Therefore, it is important to identify the UVR levels present under various conditions. Methods: We experimentally evaluated the UVR levels emitted in gas metal arc welding (GMAW) of mild steel. We used both a pulsed welding current and a non-pulsed welding current. The shielding gases were 80% Ar + 20% CO2 and 100% CO2. The effective irradiance defined in the American Conference of Governmental Industrial Hygienists guidelines was used to quantify the UVR hazard. Results: The effective irradiance measured in this study was in the range of 0.51-12.9 mW/cm2 at a distance of 500 mm from the arc. The maximum allowable exposure times at these levels are only 0.23-5.9 s/day. Conclusions: The following conclusions were made regarding the degree of hazard from UVR exposure during the GMAW of mild steel: (1) It is more hazardous at higher welding currents than at lower welding currents. (2) At higher welding currents, it is more hazardous when 80% Ar + 20% CO2 is used as a shielding gas than when 100% CO2 is used. (3) It is more hazardous for pulsed welding currents than for non-pulsed welding currents. (4) It appears to be very hazardous when metal transfer is the spray type. This study demonstrates that unprotected exposure to UVR emitted by the GMAW of mild steel is quite hazardous.
Objectives: The present study aimed to examine the buffering effect of workplace social capital (WSC) on the association of job insecurity with psychological distress in Japanese employees. Methods: 2,971 employees from two factories of a manufacturing company in Japan completed a self-administered questionnaire including the scales on job insecurity, WSC, psychological distress, demographic and occupational characteristics, and quantitative workload. Using psychological distress (defined as a total score of the K6 scale ≥5) as a dependent variable, multiple logistic regression analyses were conducted. In a series of analyses, interaction term of job insecurity×WSC was included in the model. Results: After adjusting for demographic and occupational characteristics as well as for quantitative workload and interaction effect of quantitative workload×WSC, high job insecurity and low WSC were significantly associated with psychological distress. Furthermore, a significant interaction effect of job insecurity×WSC was observed. Specifically, the association of job insecurity with psychological distress was greater among those who perceived lower levels of WSC (prevalence odds ratio=3.79 [95% confidence interval=2.70-5.32] for high vs. low job insecurity subgroup) than among those who perceived higher levels of WSC (prevalence odds ratio=2.96 [95% confidence interval=2.19-4.01] for high vs. low job insecurity subgroup). These findings were replicated among permanent male employees in the gender-stratified analyses. Conclusions: The present study suggests that WSC has a buffering effect on the association of job insecurity with psychological distress at least among Japanese permanent male employees.
Objective: Hairdressers have an increased risk for airway symptoms especially when using hair-bleaching powder containing persulfate. To minimize exposure, dust-free bleaching powder (DFP) has been made available. We studied the effects of regular powder (RP) or DFP on the airway symptoms of hairdressers with hair-bleaching associated rhinitis. Methods: Twelve hairdressers each performed three hair-bleachings on a wig in an exposure chamber. Half of the subjects used RP and half used DFP. Exposure to persulfate and ammonia was measured. Before and after each bleaching, the participants stated their degree of airway symptoms on a visual analogue scale. Nasal lavage and blood were sampled before exposure, after the last bleaching, and in the morning after exposure to measure inflammatory markers. Results: Exposure to persulfate was higher when using RP compared to DFP, 22 (11-55) vs. 12 (8-13) μg/m3; median (min-max). Exposure to ammonia did not differ between the groups. Both groups reported an increase in asthma-like symptoms and this increase was significant. Neutrophils, lymphocytes, and monocytes increased after exposure in both groups; monocytes decreased the day after. In nasal lavage, IL-8 was increased the morning after for both types of powder, and the increase was significant in the total group. IL-6 increased immediately after exposure and the day after only in the group using RP. Conclusions: Although DFP powder emits lower levels of persulfate, effects are still elicited in symptomatic hairdressers.
Objectives: To report the occurrence of an advanced case of indium lung disease with severely progressive emphysema in an indium-exposed worker. Case report: A healthy 42-year-old male smoker was employed to primarily grind indium-tin oxide (ITO) target plates, exposing him to indium for 9 years (1998-2008). In 2004, an epidemiological study was conducted on indium-exposed workers at the factory in which he worked. The subject's serum indium concentration (In-S) was 99.7 μg/l, while his serum Krebs von den Lungen-6 level was 2,350 U/ml. Pulmonary function tests showed forced vital capacity (FVC) of 4.17 l (91.5% of the JRS predicted value), forced expiratory volume in 1 s (FEV1) of 3.19 l (80.8% of predicted), and an FEV1-to-FVC ratio of 76.5%. A high-resolution chest computed tomography (HRCT) scan showed mild interlobular septal thickening and mild emphysematous changes. In 2008, he was transferred from the ITO grinding workplace to an inspection work section, where indium concentrations in total dusts had a range of 0.001-0.002 mg/m3. In 2009, the subject's In-S had increased to 132.1 μg/l, and pulmonary function tests revealed obstructive changes. In addition, HRCT scan showed clear evidence of progressive lung destruction with accompanying severe centrilobular emphysema and interlobular septal thickening in both lung fields. The subject's condition gradually worsened, and in 2015, he was registered with the Japan Organ Transplant Network for lung transplantation (LTx). Conclusions: Heavy indium exposure is a risk factor for emphysema, which can lead to a severity level that requires LTx as the final therapeutic option.
Objectives: Occupational exposure to paraffin is an infrequent cause of lipoid pneumonia (LP) and related data are scare. We investigated the possible relationship between three rare cases of chronic LP and occupational exposure to paraffin aerosol in an iron foundry. Methods: The three cases of LP and their workplaces were investigated using data from field investigations, air monitoring, pulmonary radiological examinations, cell staining, and lung biopsies. Results: The patients had long-term occupational exposure to paraffin. X-ray diffraction testing revealed that the raw material from the workshop was paraffin crystal. The air concentrations of paraffin aerosol in workplaces were significantly higher than outdoor background levels. Small diffuse and miliary shadows with unclear edges were observed throughout the whole lungs via radiography. Computed tomography revealed diffuse punctate nodules and a high density of stripe-like shadows in both lungs (ground-glass opacity in a lower lobe, and a mass-like lesion and high translucent area near the bottom of the lung). Lipid-laden macrophages were found in the sputum and bronchial lavage. A broadened alveolar septum and local focal fibrosis were also discovered via lung biopsy. The inflammatory reaction in the lung tissues appeared to resolve over time. Conclusions: These three rare cases of chronic LP in workers during molding and repair processes were associated with occupational paraffin aerosol exposure. Therefore, primary prevention is essential for molding or repairing workers in the iron foundry, and a differential diagnosis of occupational chronic LP (vs. pneumoconiosis) should be considered when treating these workers.