Occupational Health and Industrial Hygiene Commons^™

Biomonitoring Of Exposure To Multiple Metal Components In Urine, Hair And Nails Of Apprentice Welders Performing Shielded Metal Arc Welding (Smaw), Jairo Buitrago-Cortes, Philippe Sarazin, Denis Dieme, Jonathan Côté, Capucine Ouellet, Naïma El Majidi, Michèle Bouchard

Études primaires

Welding fumes are associated with various diseases. Increased air levels of metals were reported during welding. However, few multielement biomonitoring studies were conducted to assess the actual dose of metal components absorbed in apprentice welders in a learning environment. This research aimed to establish the nature and level of exposure to welding fumes and their metallic components in apprentice welders performing ‘Shielded Metal Arc Welding’ (SMAW), based on multi-element and multi-matrix analyses. A total of 86 apprentice welders were recruited in three different schools in Montreal, Québec, Canada. Twenty-one elements were measured in urine, hair, fingernail, and toenail samples collected …

Passive Earplug Including Helmholtz Resonators Arranged In Series To Achieve Broadband Near Zero Occlusion Effect At Low Frequencies, Kevin Carillo, Franck Sgard, Olivier Dazel, Olivier Doutres

Études primaires

The use of passive earplugs is often associated with the occlusion effect: a phenomenon described as the increased auditory perception of one's own physiological noise at low frequencies. As a notable acoustic discomfort, the occlusion effect penalizes the use and the efficiency of earplugs. This phenomenon is objectively characterized by the increase in sound pressure level in the occluded ear canal compared to the open ear canal. Taking inspiration from acoustic metamaterials, a new design of a three-dimensional printed “meta-earplug,” made of four Helmholtz resonators arranged in series, is proposed for achieving near zero objective occlusion effect measured on artificial …

Experiences In The Return-To-Work Process Of Workers Having Suffered Occupational Injuries In Small And Medium Size Enterprises, Jessika Audet, Alexandra Lecours, Iuliana Nastasia

Études primaires

BACKGROUND:

Small and medium-sized enterprises (SMEs) represent 95 % of businesses and are economically essential. When occupational injuries occur, scientific literature suggests that the return-to-work (RTW) success rate is proportional to the size of enterprises and the way RTW is managed may put workers in SMEs at risk. As most studies on RTW organizational practices have been conducted with large enterprises, little is known about how RTW is managed in SMEs.

OBJECTIVE:

The aim of this study was to explore SME’s organizational practices in the RTW process of workers having suffered an occupational injury.

METHODS:

Semi-structured phone interviews were conducted …

Validation Of An Emg Submaximal Method To Calibrate A Novel Dynamic Emg-Driven Musculoskeletal Model Of The Trunk: Effects On Model Estimates, Amir H. Eskandari, Farshid Ghezelbash, Aboulfazl Shirazi-Adl, Denis Gagnon, Hakim Mecheri, Christian Larivière

Études primaires

Background

Multijoint EMG-assisted optimization models are reliable tools to predict muscle forces as they account for inter- and intra-individual variations in activation. However, the conventional method of normalizing EMG signals using maximum voluntary contractions (MVCs) is problematic and introduces major limitations. The sub-maximal voluntary contraction (SVC) approaches have been proposed as a remedy, but their performance against the MVC approach needs further validation particularly during dynamic tasks.

Methods

To compare model outcomes between MVC and SVC approaches, nineteen healthy subjects performed a dynamic lifting task with two loading conditions.

Results

Results demonstrated that these two approaches produced highly correlated results …

The Relationship Between Clinical Examination Measures And Ultrasound Measures Of Fascia Thickness Surrounding Trunk Muscles Or Lumbar Multifidus Fatty Infiltrations: An Exploratory Study, Christian Larivière, Richard Preuss, Dany H. Gagnon, Hakim Mecheri, Mark Driscoll, Sharon M. Henry

Études primaires

Patients with chronic low back pain (CLBP) exhibit remodelling of the lumbar soft tissues such as muscle fatty infiltrations (MFI) and fibrosis of the lumbar multifidus (LuM) muscles, thickness changes of the thoracolumbar fascia (TLF) and perimuscular connective tissues (PMCT) surrounding the abdominal lateral wall muscles. Rehabilitative ultrasound imaging (RUSI) parameters such as thickness and echogenicity are sensitive to this remodelling. This experimental laboratory study aimed to explore whether these RUSI parameters (LuM echogenicity and fascia thicknesses), hereafter called dependent variables (DV) were linked to independent variables (IV) such as (1) other RUSI parameters (trunk muscle thickness and activation) and …

Ultrahigh-Performance Liquid Chromatography–Tandem Mass Spectrometry Quantitation Of O-Cresol In Hydrolyzed Human Urine To Assess Toluene Exposure, Eric Langlois, Sébastien Gagné

Études primaires

Rationale

Toluene is a volatile organic compound used in domestic and industrial applications. The main routes of workplace exposure to toluene are inhalation and dermal contact. As toluene exposure can cause severe nervous system damage, its quantification is crucial to prevent occupational illness. Toluene is metabolized mainly as hippuric acid, S-benzylmercapturic acid and epoxides. These are rapidly converted to o-/p-cresol, which is then excreted in the urine as conjugated glucuronides and sulfates. o-Cresol and its conjugates can be chemically hydrolyzed to form free o-cresol, which can then serve as a urinary biomarker of toluene exposure. Current …

Prerequisite For Imputing Non-Detects Among Airborne Samples In Osha’S Imis Databank: Prediction Of Sample’S Volume, Igor Burstyn, Philippe Sarazin, George Luta, Melissa C. Friesen, Laurel Kincl, Jérôme Lavoué

Études primaires

Introduction: The US Integrated Management Information System (IMIS) contains workplace measurements collected by Occupational Safety and Health Administration (OSHA) inspectors. Its use for research is limited by the lack of record of a value for the limit of detection (LOD) associated with non-detected measurements, which should be used to set censoring point in statistical analysis. We aimed to remedy this by developing a predictive model of the volume of air sampled (V) for the non-detected results of airborne measurements, to then estimate the LOD using the instrument detection limit (IDL), as IDL/V.

Methods: We obtained the Chemical Exposure Health Data …

Filtration Performance, Fit Test And Side Effects Of Respiratory Personal Protective Equipment Following Decontamination: Observations For User Safety And Comfort, Nathalie Turgeon, Melissa Pagé, Justin Robillard, Véronique Goulet, Ali Bahloul, Clothilde Brochot, Mohamed Nejib Saidi, Nathan Dumont-Leblond, Caroline Duchaine

Études primaires

Objective

While facing personal protective equipment (PPE) shortages during the COVID-19 pandemic, several institutions looked to PPE decontamination and reuse options. This study documents the effect of two hydrogen peroxide treatments on filtration efficiency and fit tests as well as the side effects for volunteers after the decontamination of N95 filtering facepiece respirators (FFRs). We also propose an efficient and large-scale treatment protocol that allows for the traceability of this protective equipment in hospitals during PPE shortages.

Methods

The effects of low-temperature hydrogen peroxide sterilization and hydrogen peroxide vapor (HPV) on two FFR models (filtration, decontamination level, residual emanation) were …

Pressure Induced By Roll-Down Foam-Earplugs On Earcanal, Ahmed Dalaq, Luiz Melo, Franck Sgard, Olivier Doutres, Éric Wagnac

Études primaires

Physical discomfort of earplug is a common complaint, so much so it jeopardizes the health and safety of workers, resulting in frequent noncompliance to proper wearing of earplugs. A pressing need thus arises to understand the underlying mechanics for the interaction of earplugs with earcanal walls. An idealized cylindrical geometry of earcanal is first treated with computational and analytical modeling to predict the pressure induced by roll-down cylindrical PVC foam earplugs. In order to predict representative pressure values and distribution, we estimated the hyperelastic properties of foam-based earplugs and characterized their behavior using a stent testing machine (J-Crimp^TM machine) …

Analysis Of Vehicle Stability When Using Two-Post Above-Ground Automotive Lifts: Support Pad Slippage, Damien Burlet-Vienney, Bertrand Galy, Kariane Cusson Bertrand, Sylvie Beaugrand, Maud Gonella, Élise Ledoux

Études primaires

Vehicles falling off two-post above-ground (2PAG) lifts is a fairly frequent occurrence. As only limited knowledge is available about the determinants influencing the stability of lifting vehicles with a 2PAG lift, two experimental designs were carried out in order to have quantitative data. This paper addresses support pad slippage as a result of external forces being exerted on a vehicle. The experimental design is based on the consultation of the key players that identify the main issues related to the support pads. The controlled factors chosen in this experimental design were lift support pad type and position, smear on pads, …

Evaluating Stability Of Human Spine In Static Tasks: A Combined In Vivo-Computational Study, Farshid Ghezelbash, Ali Shahvarpour, Christian Larivière, Aboulfazl Shirazi-Adl

Études primaires

Various interpretations and parameters have been proposed to assess spinal stability such as antagonist muscle coactivity, trunk stiffness and spinal buckling load; however, the correlation between these parameters remains unknown. We evaluated spinal stability during different tasks while changing the external moment and load height and investigated likely relationships between different EMG- and model-based parameters (e.g., EMG coactivity ratio, trunk stiffness, force coactivity ratio) and stability margins. EMG and kinematics of 40 young healthy subjects were recorded during various quasi-static tasks. Muscle forces, trunk stiffness and stability margins were calculated by a nonlinear subject-specific EMG-assisted-optimization musculoskeletal model of the trunk. …

Knee Braces And Foot Orthoses Multimodal Treatment Of Medial Knee Osteoarthritis, Xavier Robert-Lachaine, Yoann Dessery, Étienne L. Belzile, Philippe Corbeil

Études primaires

Background

Knee braces and lateral wedge foot orthoses are two treatment options recommended for medial knee osteoarthritis, but the combination of both of them could further improve their effectiveness.

Research question

The aim was to evaluate whether the combination of lateral wedge foot orthoses with two types of knee brace enhances the biomechanical effects and pain relief during the stance phase of gait while maintaining comfort.

Methods

Ten patients with medial knee osteoarthritis were fitted with a standard valgus brace, an unloader brace with valgus and external rotation functions, and 7° lateral wedge foot orthoses. The pain relief, comfort, kinematics …

Risk-Targeted Behavioral Activation For The Management Of Work Disability Associated With Comorbid Pain And Depression: A Feasibility Study, Michael J.L. Sullivan, Timothy Wideman, Nathalie Gauthier, Pascal Thibault, Tamra Ellis, Heather Adams

Études primaires

Purpose

The purpose of the present study was to conduct a preliminary evaluation of the feasibility and impact of a risk-targeted behavioral activation intervention for work-disabled individuals with comorbid pain and depression.

Methods

The design of the study was a single-arm non-randomized trial. The sample consisted of 66 work-disabled individuals with comorbid pain and depression. The treatment program consisted of a 10-week standardized behavioral activation intervention supplemented by techniques to target two psychosocial risk factors for delayed recovery, namely, catastrophic thinking and perceptions of injustice. Measures of pain severity, depression, catastrophic thinking, perceived injustice, and self-reported disability were completed pre-, …

Occupational Exposure To Wood Dust And The Burden Of Nasopharynx And Sinonasal Cancer In Canada, Amirabbas Mofidi, Emile Tompa, Christina Kalcevich, Christopher Mcleod, Martin Lebeau, Chaojie Song, Joanne Kim, Paul A. Demers

Études primaires

Background: Millions of workers around the world are exposed to wood dust, as a by-product of woodworking. Nasopharynx cancers (NPCs) and sinonasal cancers (SNCs) are two cancers that can be caused by occupational exposure to wood dust, but there is little evidence regarding their burden in Canada. Objective: the aim of this study was to estimate the incidence and economic burden of newly diagnosed cases of NPC and SNC in 2011 in Canada, attributable to occupational exposures to wood dust. Methods: calculating the incidence of cancer attributable to occupational exposure involved three steps of defining relative risk, assessing the prevalence …

Microbial Contamination And Metabolite Exposure Assessment During Waste And Recyclable Material Collection, Fabiola Salambaga, Loïc Wingert, Isabelle Valois, Nancy Lacombe, François Gouin, Julien Trépanier, Maximilien Debia, Ewelina Soszczyńska, Magdalena Twarużek, Robert Kosicki, Marta Dias, Susana Viegas, Liliana Caetano, Carla Viegas, Geneviève Marchand

Études primaires

Waste workers are exposed to bioaerosols when handling, lifting and dumping garbage. Bioaerosol exposure has been linked to health problems such as asthma, airway irritant symptoms, infectious, gastrointestinal and skin diseases, and cancer. Our objective was to characterize the exposure of urban collectors and drivers to inhalable bioaerosols and to measured the cytotoxic effect of air samples in order to evaluate their health risk.

Personal and ambient air sampling were conducted during the summer of 2019. Workers from 12 waste trucks collecting recyclables, organic waste or compost were evaluated. Bacteria and fungi were cultured, molecular biology methods were used to …

Development Of A New Spe Uplc–Ms/Ms Method For Extraction And Quantitation Of Toluene Diamine On Gloves Following Toluene Diisocyanate Exposure, Asma Daoud, Pierre-Luc Cloutier, Sébastien Gagné, Livain Breau, Jacques Lesage

Études primaires

Rationale

Toluene diisocyanate (TDI) is a highly reactive isocyanate commonly used as a mixture of 2,4- and 2,6- isomers in the production of flexible foams. Exposure to TDI occurs primarily through vapour inhalation in workplaces where TDI is produced or used, but dermal exposure is also possible during some tasks. To ensure workplace safety, accurate monitoring of TDI and toluene diamine (TDA) levels is required. Methods of quantifying field effectiveness of gloves in preventing dermal exposure have not been established. Therefore, there is a need to develop a new practical method for assessing glove effectiveness for TDI/TDA.

Method

A new …

Endocrine Disruptors: Challenges And Future Directions In Epidemiologic Research, V. Ho, L. Pelland-St-Pierre, S. Gravel, M. F. Bouchard, M.-A. Verner, F. Labrèche

Études primaires

Public concern about the impact of endocrine disrupting chemicals (EDCs) on both humans and the environment is growing steadily. Epidemiologic research provides key information towards our understanding of the relationship between environmental exposures like EDCs and human health outcomes. Intended for researchers in disciplines complementary to epidemiology, this paper highlights the importance and challenges of epidemiologic research in order to present the key elements pertaining to the design and interpretation of an epidemiologic study on EDCs.

The conduct of observational studies on EDCs derives from a thoughtful research question, which will help determine the subsequent methodological choices surrounding the careful …

Morphologic Clustering Of Earcanals Using Deep Learning Algorithm To Design Artificial Ears Dedicated To Earplugs Attenuation Measurement, Bastien Poissenot-Arrigoni, Chun Hong Law, Djamal Berbiche, Franck Sgard, Olivier Doutres

Études primaires

Designing earplugs adapted for the widest number of earcanals requires acoustical test fixtures (ATFs) geometrically representative of the population. Most existing ATFs are equipped with unique sized straight cylindrical earcanals, considered representative of average human morphology, and are therefore unable to assess how earplugs can fit different earcanal morphologies. In this study, a methodology to cluster earcanals as a function of their morphologies with the objective of designing artificial ears dedicated to sound attenuation measurement is developed and applied to a sample of Canadian workers’ earcanals. The earcanal morphologic indicators that correlate with the attenuations of six models of commercial …

Risk-Based Inspection Applied To Two-Post Above-Ground Automotive Lifts, Damien Burlet-Vienney, François Gauthier, Bertrand Galy

Études primaires

The safe use of two-post above-ground automotive lifts (2PAG lifts) has received particular attention in the province of Québec (Canada) following the death of a young mechanic. The inspection and preventive maintenance of this equipment is a problem highlighted in accident investigation reports and by representatives of the sector. Therefore, the work presented in this article aimed at proposing a complete and detailed inspection grid for 2PAG lifts by establishing an exhaustive list of verification criteria, baseline states and the inspection frequency for each criterion according to their criticality. The grid was built from standards, existing grids, manufacturers’ manuals, interviews …

Stay At Work After A Period Of Disability Due To An Occupational Injury: A Complex Process Marked By Social Exchanges, Alexandra Lecours, Marie-José Durand, Marie-France Coutu, Charles Groleau, Roxanne Bédard-Mercier

Études primaires

Purpose Rooted in a social exchange lens, this study aimed to explore the interactions between the factors influencing stay at work after a period of disability due to an occupational injury. Methods Based on a descriptive interpretative research design, interviews with 15 participants (i.e., representatives of workers, workplaces, insurers, and the health care system) were conducted to gather their perspectives about stay at work. Qualitative data was analyzed through thematic analysis. Results Ten different factors interacting together and influencing stay at work were identified. These factors prevail either during stay at work or previously. They are either related to the …

Submaximal Electromyography-Driven Musculoskeletal Modeling Of The Human Trunk During Static Tasks: Equilibrium And Stability Analyses, Farshid Ghezelbash, Aboulfazl Shirazi-Adl, Denis Gagnon, Ali Shahvarpour, Navid Arjmand, Amir Hossein Eskandari, Christian Larivière

Études primaires

Conventional electromyography-driven (EMG) musculoskeletal models are calibrated during maximum voluntary contraction (MVC) tasks, but individuals with low back pain cannot perform unbiased MVCs. To address this issue, EMG-driven models can be calibrated in submaximal tasks. However, the effects of maximal (when data points include the maximum contraction) and submaximal calibration techniques on model outputs (e.g., muscle forces, spinal loads) remain yet unknown. We calibrated a subject-specific EMG-driven model, using maximal/submaximal isometric contractions, and simulated different independent tasks. Both approaches satisfactorily predicted external moments (Pearson’s correlation ∼ 0.75; relative error = 44%), and removing calibration tasks under axial torques markedly improved …

Occupational Exposure To Antineoplastic Drugs: What About Hospital Sanitation Personnel?, France Labrèche, Capucine Ouellet, Brigitte Roberge, Nicolas J Caron, Ahmed Yennek, Jean-François Bussières

Études primaires

Objective

Occupational exposure to antineoplastic drugs (ANPs) occurs mainly through dermal contact. Our study was set up to assess the potential exposure of hospital sanitation (HS) personnel, for whom almost no data are available, through contamination of surfaces they regularly touch.

Methods

In the oncology departments of two hospitals around Montreal, surface wipe samples of 120–2000 cm² were taken at 10 sites cleaned by the HS personnel and five other sites frequently touched by nursing and pharmacy personnel. A few hand wipe samples were collected to explore skin contamination. Wipes were analyzed by ultra-performance liquid chromatography tandem–mass spectrometry for …

Leakage Versus Material Filtration In Barrier Facemask Efficiency, Ali Bahloul, Clothilde Brochot, Barbara Layne

Études primaires

The World Health Association and many governmental agencies recommend the wearing of facemasks by the general public to prevent the spread of COVID-19. It is believed that masks can significantly protect others and may offer some protection to the wearer. Although there are standards for FFRs, surgical masks, and recently for barrier face coverings, they all indicate the level of protection for the wearer. However, testing facial masks not at the point of inhalation, but at the source, the exhale, offers a new perspective on how to impede particle emissions. In this paper, the experimental results show that, although the …

On The Removal Of The Open Earcanal High-Pass Filter Effect Due To Its Occlusion: A Bone-Conduction Occlusion Effect Theory, Kevin Carillo, Olivier Doutres, Franck Sgard

Études primaires

The occlusion effect is commonly experienced by in-ear device wearers as an increased loudness sensation of bone-conducted low frequency sounds. A widespread theory proposed by Tonndorf and based on a simplified electro-acoustic model describes the phenomenon as the removal of the open earcanal high-pass filter effect due to a perfect or partial occlusion. However, this filter has not been clearly defined and several ambiguities remain. Revisiting the model, a second order high-pass filter effect for the volume velocity transferred between the earcanal wall and the eardrum is highlighted. This filter remains for partial occlusion but vanishes for perfect occlusion. In …

Role And Responsibilities Of Supervisors In The Sustainable Return To Work Of Workers Following A Work-Related Musculoskeletal Disorder, Iuliana Nastasia, Marie-France Coutu, Romain Rives, Jessica Dubé, Sarah Gaspard, Audrey Quilicot

Études primaires

Purpose Supervisors play an important role during the return to work (RTW) of injured workers. Yet little research has been done on the actions associated with this role or the contexts in which they are taken. The purpose of this study was to develop courses of action to promote supervisors’ involvement in the process aimed at achieving sustainable RTW for workers following a work-related musculoskeletal disorder (MSD), and to verify their pertinence, feasibility, and applicability in practice. Methods A two-phase qualitative method was used. (1) Secondary content analysis of 46 interviews of 14 workers post-MSD and 32 other actors in …

Principle Of An Acoustical Method For Estimating The Centroid Position Of The Earcanal Wall Normal Velocity Induced By Bone-Conducted Stimulation: Numerical Evaluation, Kevin Carillo, Olivier Doutres, Franck Sgard

Études primaires

The occlusion effect is commonly experienced as the altered perception of one’s own physiological noise when the earcanal entrance is blocked. Objectively, this phenomenon corresponds to an acoustic pressure increase in the occluded earcanal. The occlusion effect originates from the earcanal wall normal vibration and depends on the spatial distribution of the latter. At low frequencies, this spatial distribution can be characterized by the position of its centroid along the earcanal middle axis. This paper describes the principle of an acoustical method for estimating this centroid position at low frequencies. The proposed method consists in measuring the eardrum acoustic pressure …

The Effect Of Extensible And Non-Extensible Lumbosacral Orthoses On Anticipatory Postural Adjustments In Participants With Low Back Pain And Healthy Controls, Christian Larivière, Richard Preuss

Études primaires

Background

Wearing a lumbosacral orthosis (LSO) is known to influence spine mechanics, but less is known about how LSOs affect motor control. Whether the use of a LSO can negatively affect motor control of the lumbar spine is still under debate.

Objective

The current study examined the immediate effects of two flexible LSOs (extensible and non-extensible) on the anticipatory postural adjustments that prepare the spine for a predictable perturbation.

Design

A comparative study using a repeated measures design in a laboratory setting.

Methods

Healthy controls (n = 20) and participants with low back pain (n = 40) performed a rapid …

Structural Remodeling Of The Lumbar Multifidus, Thoracolumbar Fascia And Lateral Abdominal Wall Perimuscular Connective Tissues: A Search For Its Potential Determinants, Christian Larivière, Sharon M. Henry, Richard Preuss

Études primaires

Recently remodeling of lumbar soft tissues has received increased research attention. However, the major determinants that influence remodeling need to be elucidated in order to understand the impact of different rehabilitation modalities on tissue remodeling. The main aim of this study was to explore the between-subject variance of different measures of lumbar soft tissues quantified with rehabilitative ultrasound imaging (RUSI). RUSI measures (n = 8) were collected from 30 subjects without and 34 patients with LBP: (1) lumbar multifidus (LM) echogenicity (fatty infiltration/fibrosis) at three vertebral levels (L3/L4, L4/L5 and L5/S1) (n = 3); (2) posterior layer thickness …

Structural Remodeling Of The Lumbar Multifidus, Thoracolumbar Fascia And Lateral Abdominal Wall Perimuscular Connective Tissues: Medium-Term Test-Retest Reliability Of Ultrasound Measures, Christian Larivière, Dany H. Gagnon, Richard Preuss

Études primaires

Abstract

Introduction

Growing interest is being paid to the lumbar multifidus (LM) intramuscular fatty infiltrations and fibrosis that are secondary to low back pain as well to the remodeling of perimuscular connective tissues (fasciae) such as the thoracolumbar fascia and fascia sheets separating the abdominalwall muscles. Magnetic resonanceimaging and computed tomography have traditionally been used but rehabilitative ultrasound imaging (RUSI) is much more affordable and practical, which can accelerate research and clinical applications on this topic. The aim of this study was to test the medium-term (8 weeks) test-retest reliability of the corresponding RUSI measures.

Methods

Thirty-four participants …

Combined Influence Of Transfer Distance, Pace, Handled Mass And Box Height On Spine Loading And Posture, Xavier Robert-Lachaine, Philippe Corbeil, Antoine Muller, Jasmin Vallée-Marcotte, Hakim Mecheri, Denys Denis, André Plamondon

Études primaires

Work-related low back disorders are commonly associated with handling tasks. The objective of this study was to determine the combined influence of distance, pace, handled mass and height, on back loading and posture during free box transfer. Kinematics and kinetics of 17 handlers were recorded during a box transfer task between two pallets. Four-way repeated measures ANOVA were conducted on four lift-deposit height conditions (from lift and deposit of 0.16 or 1.16 m), three distances between pallets (1.5, 1.0 and 0.5 m), two handled masses (10 and 20 kg) and two paces (free and faster). The interaction between distance and …