Availability, use, and impact of workplace mental health supports during the COVID-19 pandemic in a Canadian cohort of healthcare workers.

We investigated the availability and use of workplace mental health (MH) supports during the COVID-19 pandemic in a Canadian cohort of healthcare workers (HCW) and measured anxiety and depression by the Hospital Anxiety and Depression Scale (HADS) completed at four contacts 2020-2022. Reports were available for 4400 HCW working with patients. Half the HCWs had a clinically significant HADS score at one or more contacts Access to MH supports increased during the pandemic, with 94% reporting access to some workplace support by 2022: 47% had made use of at least one support. 25% of those with high HADS scores used no support. Older women and men with depressive conditions were less likely to report use. Reported use of an Employee Assistance Program was associated with a reduction in HADS scores in the following months.

Does recall bias explain the association of mood disorders with workplace harassment?

Purpose: To determine the contribution of recall bias to the observed excess in mental ill-health in those reporting harassment at work. Methods: A prospective cohort of 1885 workers in welding and electrical trades was contacted every six months for up to 5 years, asking whether they were currently anxious or depressed and whether this was made worse by work. Only at the end of the study did we ask about any workplace harassment they had experienced at work. We elicited sensitivity and specificity of self-reported bullying from published reliability studies and formulated priors that reflect the possibility of over-reporting of workplace harassment (exposure) by those whose anxiety or depression was reported to be made worse by work (cases). We applied the resulting misclassification models to probabilistic bias analysis (PBA) of relative risks. Results: We observe that PBA implies that it is unlikely that biased misclassification due to the study subjects' states of mind could have caused the entire observed association. Indeed, the results demonstrated that doubling of risk of anxiety or depression following workplace harassment is plausible, with the unadjusted relative risk attenuated with understated uncertainty. Conclusions: It seems unlikely that risk of anxiety or depression following workplace harassment can be explained by the form of recall bias that we proposed.

Work Characteristics, Workplace Support, and Mental Ill-Health in a Canadian Cohort of Healthcare Workers During the COVID-19 Pandemic.

OBJECTIVE: The aim of the study was to identify determinants of mental health in healthcare workers (HCW) during the COVID-19 pandemic. METHODS: A cohort of Canadian HCW completed four questionnaires giving details of work with patients, ratings of workplace supports, a mental health questionnaire, and substance use. Principal components were extracted from 23 rating scales. Risk factors were examined by Poisson regression. RESULTS: A total of 4854 (97.8%) of 4964 participants completed ratings and mental health questionnaires. Healthcare workers working with patients with COVID-19 had high anxiety and depression scores. One of three extracted components, 'poor support,' was related to work with infected patients and to anxiety, depression, and substance use. Availability of online support was associated with feelings of better support and less mental ill-health. CONCLUSIONS: Work with infected patients and perceived poor workplace support were related to anxiety and depression during the pandemic.

Reported harassment and mental ill-health in a Canadian prospective cohort of women and men in welding and electrical trades.

OBJECTIVES: Experience of psychosocial environments by workers entering trade apprenticeships may differ by gender. We aimed to document perceived harassment and to investigate whether this related to mental ill-health. METHODS: Cohorts of workers in welding and electrical trades were established, women recruited across Canada and men from Alberta. Participants were recontacted every 6 months for up to 3 years (men) or 5 years (women). At each contact, they were asked about symptoms of anxiety and depression made worse by work. After their last regular contact, participants received a "wrap-up" questionnaire that included questions on workplace harassment. In Alberta, respondents who consented were linked to the administrative health database that recorded diagnostic codes for each physician contact. RESULTS: One thousand eight hundred and eighty five workers were recruited, 1,001 in welding trades (447 women), and 884 in electrical trades (438 women). One thousand four hundred and nineteen (75.3%) completed a "wrap up" questionnaire, with 1,413 answering questions on harassment. Sixty percent of women and 32% of men reported that they had been harassed. Those who reported harassment had more frequently recorded episodes of anxiety and depression made worse by work in prospective data. In Alberta, 1,242 were successfully matched to administrative health records. Those who reported harassment were more likely to have a physician record of depression since starting their trade. CONCLUSIONS: Tradeswomen were much more likely than tradesmen to recall incidents of harassment. The results from record linkage, and from prospectively collected reports of anxiety and depression made worse by work, support a conclusion that harassment resulted in poorer mental health.

Determinants of SARS-CoV-2 IgG response and decay in Canadian healthcare workers: A prospective cohort study.

INTRODUCTION: Healthcare workers (HCWs) from an interprovincial Canadian cohort gave serial blood samples to identify factors associated with anti-receptor binding domain (anti-RBD) IgG response to the SARS-CoV-2 virus. METHODS: Members of the HCW cohort donated blood samples four months after their first SARS-CoV-2 immunization and again at 7, 10 and 13 months. Date and type of immunizations and dates of SARS-CoV-2 infection were collected at each of four contacts, together with information on immunologically-compromising conditions and current therapies. Blood samples were analyzed centrally for anti-RBD IgG and anti-nucleocapsid IgG (Abbott Architect, Abbott Diagnostics). Records of immunization and SARS-CoV-2 testing from public health agencies were used to assess the impact of reporting errors on estimates from the random-effects multivariable model fitted to the data. RESULTS: 2752 of 4567 vaccinated cohort participants agreed to donate at least one blood sample. Modelling of anti-RBD IgG titer from 8903 samples showed an increase in IgG with each vaccine dose and with first infection. A decrease in IgG titer was found with the number of months since vaccination or infection, with the sharpest decline after the third dose. An immunization regime that included mRNA1273 (Moderna) resulted in higher anti-RBD IgG. Participants reporting multiple sclerosis, rheumatoid arthritis or taking selective immunosuppressants, tumor necrosis factor inhibitors, calcineurin inhibitors and antineoplastic agents had lower anti-RBD IgG. Supplementary analyses showed higher anti-RBD IgG in those reporting side-effects of vaccination, no relation of anti-RBD IgG to obesity and lower titers in women immunized in early or mid-pregnancy. Sensitivity analysis results suggested no important bias in the self-report data. CONCLUSION: Creation of a prospective cohort was central to the credibility of results presented here. Serial serology assessments, with longitudinal analysis, provided effect estimates with enhanced accuracy and a clearer understanding of medical and other factors affecting response to vaccination.

Excess risk of COVID-19 infection and mental distress in healthcare workers during successive pandemic waves: Analysis of matched cohorts of healthcare workers and community referents in Alberta, Canada.

OBJECTIVES: To investigate changes in risk of infection and mental distress in healthcare workers (HCWs) relative to the community as the COVID-19 pandemic progressed. METHODS: HCWs in Alberta, Canada, recruited to an interprovincial cohort, were asked consent to link to Alberta's administrative health database (AHDB) and to information on COVID-19 immunization and polymerase chain reaction (PCR) testing. Those consenting were matched to records of up to five community referents (CRs). Physician diagnoses of COVID-19 were identified in the AHDB from the start of the pandemic to 31 March 2022. Physician consultations for mental health (MH) conditions (anxiety, stress/adjustment reaction, depressive) were identified from 1 April 2017 to 31 March 2022. Risks for HCW relative to CR were estimated by fitting wave-specific hazard ratios. RESULTS: Eighty percent (3050/3812) of HCWs consented to be linked to the AHDB; 97% (2959/3050) were matched to 14,546 CRs. HCWs were at greater risk of COVID-19 overall, with first infection defined from either PCR tests (OR=1.96, 95%CI 1.76-2.17) or physician records (OR=1.33, 95%CI 1.21-1.45). They were also at increased risk for each of the three MH diagnoses. In analyses adjusted for confounding, risk of COVID-19 infection was higher than for CRs early in the pandemic and during the fifth (Omicron) wave. The excess risk of stress/adjustment reactions (OR=1.52, 95%CI 1.35-1.71) and depressive conditions (OR=1.39, 95%CI 1.24-1.55) increased with successive waves during the epidemic, peaking in the fourth wave. CONCLUSION: HCWs were at increased risk of both COVID-19 and mental ill-health with the excess risk continuing late in the pandemic.

RéSUMé: OBJECTIFS: Étudier l'évolution du risque d'infection et de problèmes de santé mentale (PSM) chez les travailleurs de la santé (TdS), comparé à la population générale, au cours de la pandémie de COVID-19. MéTHODES: Certains TdS de l'Alberta (Canada) participant à une cohorte interprovinciale, ont consenti à ce que la base administrative de santé de l'Alberta (AHDB) nous transmette leurs données de vaccination contre la COVID-19 et de tests d'amplification des acides nucléiques (TAAN). Ceux ayant consenti ont été appariés à un maximum de cinq témoins de population générale. Les diagnostics médicaux (par médecins) de COVID-19 ont été identifiés dans l'AHDB du début de la pandémie jusqu'au 31 mars 2022. Les consultations médicales pour PSM (anxiété, stress/troubles de l'adaptation, dépression) ont été identifiées entre le 1er avril 2017 et le 31 mars 2022. Les rapports de cotes (RC) comparant les TdS aux témoins de la population générale ont été estimés pour chaque vague d'infection. RéSULTATS: Quatre-vingts pourcent (80 %; 3050/3812) des TdS ont donné leur consentement à ce que leurs données nous soient transmises par l'AHDB; 97 % d'entre eux (2959/3050) ont été appariés à 14 546 témoins. Dans l'ensemble, les TdS étaient plus à risque de COVID-19, avec une première infection identifiée soit par les TANN (RC=1,96, IC de 95% 1,76-2,17), soit via les dossiers médicaux (RC=1,33, IC de 95% 1,21-1,45). Ils étaient également plus à risque pour chacun des trois problèmes de SM. Le risque de COVID-19 ajustés pour les facteurs de confusion était plus élevé que chez les témoins au début de la pandémie et durant la cinquième vague (variant Omicron). Les excès de risque de stress/troubles de l'adaptation (RC=1,52, IC de 95% 1,35-1,71) et de dépression (RC=1,39, IC de 95% 1,24-1,55) ont augmenté au fil des vagues de l'épidémie, avec un pic à la quatrième vague. CONCLUSION: Les TdS étaient plus à risque d'infection de COVID-19 et de troubles de santé mentale avec cet excès de risque se prolongeant plus tard dans la pandémie.

Cohort profile: recruitment and retention in a prospective cohort of Canadian healthcare workers during the COVID-19 pandemic.

PURPOSE: Healthcare workers were recruited early in 2020 to chart effects on their health as the COVID-19 pandemic evolved. The aim was to identify modifiable workplace risk factors for infection and mental ill health. PARTICIPANTS: Participants were recruited from four Canadian provinces, physicians (medical doctors, MDs) in Alberta, British Columbia, Ontario and Quebec, registered nurses (RNs), licensed practical nurses (LPNs) and healthcare aides (HCAs) in Alberta and personal support workers (PSWs) in Ontario. Volunteers gave blood for serology testing before and after vaccination. Cases with COVID-19 were matched with up to four referents in a nested case-referent study. FINDINGS TO DATE: Overall, 4964/5130 (97%) of those recruited joined the longitudinal cohort: 1442 MDs, 3136 RNs, 71 LPNs, 235 PSWs, 80 HCAs. Overall, 3812 (77%) were from Alberta. Prepandemic risk factors for mental ill health and respiratory illness differed markedly by occupation. Participants completed questionnaires at recruitment, fall 2020, spring 2021, spring 2022. By 2022, 4837 remained in the cohort (127 had retired, moved away or died), for a response rate of 89% (4299/4837). 4567/4964 (92%) received at least one vaccine shot: 2752/4567 (60%) gave postvaccine blood samples. Ease of accessing blood collection sites was a strong determinant of participation. Among 533 cases and 1697 referents recruited to the nested case-referent study, risk of infection at work decreased with widespread vaccination. FUTURE PLANS: Serology results (concentration of IgG) together with demographic data will be entered into the publicly accessible database compiled by the Canadian Immunology Task Force. Linkage with provincial administrative health databases will permit case validation, investigation of longer-term sequelae of infection and comparison with community controls. Analysis of the existing dataset will concentrate on effects on IgG of medical condition, medications and stage of pregnancy, and the role of occupational exposures and supports on mental health during the pandemic.

Determinants of Sickness Absence Duration After Mild COVID-19 in a Prospective Cohort of Canadian Healthcare Workers.

OBJECTIVE: The aim of the study is to identify modifiable factors associated with sickness absence duration after a COVID-19 infection. METHODS: Participants in a prospective cohort of 4964 Canadian healthcare workers were asked how many working days they had missed after a positive COVID-19 test. Only completed episodes with absence ≤31 working day and no hospital admission were included. Cox regression estimated the contribution of administrative guidelines, vaccinations, work factors, personal characteristics, and symptom severity. RESULTS: A total of 1520 episodes of COVID-19 were reported by 1454 participants. Days off work reduced as the pandemic progressed and were fewer with increasing numbers of vaccines received. Time-off was longer with greater symptom severity and shorter where there was a provision for callback with clinical necessity. CONCLUSIONS: Vaccination, an important modifiable factor, related to shorter sickness absence. Provision to recall workers at time of clinical need reduced absence duration.

The evolution of workplace risk for Covid-19 in Canadian healthcare workers and its relation to vaccination: A nested case-referent study.

BACKGROUND: During the early months of the Covid-19 pandemic, studies demonstrated that healthcare workers (HCWs) were at increased risk of infection. Few modifiable risks were identified. It is largely unknown how these evolved over time. METHODS: A prospective case-referent study was established and nested within a cohort study of Canadian HCWs. Cases of Covid-19, confirmed by polymerase chain reaction, were matched with up to four referents on job, province, gender, and date of first vaccination. Cases and referents completed a questionnaire reporting exposures and experiences in the 21 days before case date. Participants were recruited from October 2020 to March 2022. Workplace factors were examined by mixed-effects logistic regression allowing for competing exposures. A sensitivity analysis was limited to those for whom family/community transmission seemed unlikely. RESULTS: 533 cases were matched with 1697 referents. Among unvaccinated HCWs, the risk of infection was increased if they worked hands-on with patients with Covid-19, on a ward designated for care of infected patients, or handled objects used by infected patients. Sensitivity analysis identified work in residential institutions and geriatric wards as high risk for unvaccinated HCWs. Later, with almost universal HCW vaccination, risk from working with infected patients was much reduced but cases were more likely than referents to report being unable to access an N95 mask or that decontaminated N95 masks were reused. CONCLUSIONS: These results suggest that, after a rocky start, the risks of Covid-19 infection from work in health care are now largely contained in Canada but with need for continued vigilance.

Exposures to Polycyclic Aromatic Hydrocarbons and Their Mitigation in Wildland Firefighters in Two Canadian Provinces.

OBJECTIVES: We aimed to characterize polycyclic aromatic hydrocarbons (PAHs) in the breathing zone and on the skin of wildland firefighters and to assess their contribution to urinary 1-hydroxypyrene (1-HP) over repeated firefighting rotations. We asked if improved skin hygiene or discretionary use of an N95 mask would reduce absorption. METHODS: In collaboration with wildfire services of two Canadian provinces, Alberta and British Columbia (BC), we recruited wildland firefighters from crews willing to be followed up over successive rotations and to be randomly assigned to normal practice, enhanced skin hygiene (ESH), or ESH plus discretionary use of an N95 mask. We collected spot urine samples at the beginning and end of up to four rotations/firefighter. On designated fire days, as close as possible to the end of rotation, we collected skin wipes from the hands, throat, and chest at the beginning and end of the fire day and, in BC, start of fire-day urine samples. Volunteers carried air monitoring pumps. Participants completed questionnaires at the beginning and end of rotations. Exposure since the start of the fire season was estimated from fire service records. Urinary 1-HP was analyzed by LC-MS-MS. Analysis of 21 PAHs on skin wipes and 27 PAHs from air sampling was done by GC-MS-MS. Statistical analysis used a linear mixed effects model. RESULTS: Firefighters in Alberta were recruited from five helitack crews and two unit crews, and in BC from two unit crews with 80 firefighters providing data overall. The fire season in BC was very active with five monitored fire days. In Alberta, with more crews, there were only seven fire days. Overall, log 1-HP/creatinine (ng/g) increased significantly from the start (N = 145) to end of rotation (N = 136). Only three PAHs (naphthalene, phenanthrene, and pyrene) were found on >20% of skin wipes. PAHs from 40 air monitoring pumps included 10 PAHs detected on cassette filters (particles) and 5 on sorbent tubes (vapor phase). A principal component extracted from air monitoring data represented respiratory exposure and total PAH from skin wipes summarized skin exposure. Both routes contributed to the end of rotation urinary 1-HP. The ESH intervention was not demonstrated to effect absorption. Allocation of an N95 mask was associated with lower 1-HP when modeling respiratory exposure (ß = -0.62, 95% CI -1.15 to -0.10: P = 0.021). End of rotation 1-HP was related to 1-HP at the start of the next rotation (ß = 0.25, 95% CI 0.12 to 0.39: P < 0.001). CONCLUSIONS: Exposures to PAHs during firefighting were significant, with samples exceeding the American Conference of Governmental Industrial Hygienists Biological Exposure Index for 1-HP suggesting a need for control of exposure. PAH exposure accumulated during the rotation and was not fully eliminated during the break between rotations. Both respiratory and skin exposures contributed to 1-HP. While improved skin hygiene may potentially reduce dermal absorption, that was not demonstrated here. In contrast, those allocated to discretionary use of an N95 mask had reduced 1-HP excretion. Wildland firefighters in North America do not use respiratory protection, but the results of this study support more effective interventions to reduce respiratory exposure.

Respiratory Tract and Eye Symptoms in Wildland Firefighters in Two Canadian Provinces: Impact of Discretionary Use of an N95 Mask during Successive Rotations.

We examined whether discretionary use of an N95 mask reduced symptom reporting in wildland firefighters. The study collected data from two Canadian provinces during the 2021 fire season, with each firefighter followed for up to 4 rotations. Participants completed questionnaires on symptoms at the start and end of each rotation, when they reported also on mask use (if any) and completed a task checklist. Eighty firefighters contributed data. Nineteen firefighters were successfully fit-tested for N95 masks to wear whenever they felt conditions justified. Start-of-rotation symptoms reflected total hours firefighting in 2021. Symptoms of eye, nose and throat irritation and cough were more bothersome at the end of rotation. Cough, throat and nose (but not eye) symptoms were reported as significantly less bothersome at the end of rotation by those allocated masks, having allowed for crew type and start-of-rotation symptoms. Among those allocated a mask, use was most frequent during initial attack and least during driving and patrol. Reasons for not wearing included high work difficulty and low comfort. It is concluded that symptoms in wildland firefighters increased with hours of exposure. While provision of an N95 mask reduced symptoms, work is needed to overcome barriers to respiratory protection.

Pregnancy Outcome in Women Exposed to Metal Fume in Welding: A Canadian Cohort Study.

OBJECTIVES: Welding is a physically demanding job that entails exposure to metal fume and particles. There is little information on the effect of welding exposures on the outcome of a pregnancy conceived during a period when a woman was employed as a welder. METHODS: Women welders recruited to the Workers Health in Apprenticeship Trades-Metal and Electrical (WHAT-ME) study were followed-up every 6 months for up to 5 years (January 2011-August 2018), and every pregnancy recorded. At the first 6-month follow-up, a detailed questionnaire was completed for the most recent day in welding, and this information was collected again at each follow-up and also from questionnaires completed during pregnancy. The date of conception was estimated for each pregnancy and the job at that date identified. Exposures to ergonomic factors, work schedule and perceptions of noise, heat and cold were extracted for the job at conception. Exposures to metals (aluminum, chromium, manganese, and nickel) and particles in welding fume were estimated from previously validated exposure algorithms reflecting the welding process, base metal and consumables of the job at the conception date. The effects of exposures were estimated in multilevel multivariable models allowing for confounding. RESULTS: There were 242 pregnancies conceived by a welder working in her trade, 87 were before the first follow-up, 3 were after first follow-up but detailed information was not collected, 22 of those potentially included in the assessment group were in-trade but not welding leaving 122 pregnancies in 90 welders for analysis. Of these 91 resulted in a live birth and 31 in a fetal loss (27 miscarriages and 4 stillbirths). Mean birth weight for live births was 3365 g and gestation 39.4 weeks. Final models showed that risk of fetal loss increased with manipulating heavy objects [odds ratio (OR) = 5.13, 95% confidence interval (CI) 2.04-12.92], whole-body vibration (OR = 5.86, 95% CI 1.81-18.92), a higher rating for noise exposure intensity (OR = 1.52, 95% CI 1.24-1.85), and decreased with use of local exhaust ventilation (OR = 0.20, 95% CI 0.03-1.18). Gestation decreased with perceived heat intensity (ß = -0.15, 95% CI -0.29 to -0.02) and number of previous pregnancies (ß = -0.35, 95% CI -0.65 to -0.05). Birth weight was lower in those reporting whole-body vibration (ß = -596 g, 95% CI -924 to -267) and increased with the welder's body mass index (ß = 36 g, 95% CI 12-61). Estimates of exposure to metals and particles were unrelated to gestation or birth weight. In a bivariate analysis, allowing for the same welder reporting >1 pregnancy, estimated airborne aluminum exposure (and to a lesser degree exposure to nickel and particles) was related to greater risk of fetal loss (OR = 1.52, 95% CI 1.04-2.24) but neither aluminum nor the other estimated elements of welding fume added to the final model. CONCLUSIONS: In this group of women actively engaged in welding during the time surrounding conception, the outcome of pregnancy was strongly related to work exposures, particularly vibration (reported in grinding tasks), manipulation of heavy objects, and perceived intensity of noise and heat. The study was unable to show an independent effect of exposure to metal fume constituents.

Urinary Metals as a Marker of Exposure in Men and Women in the Welding and Electrical Trades: A Canadian Cohort Study.

OBJECTIVES: Men and women working in the welding trades undergo the same apprenticeship training but it is unknown whether, once in the trade, their exposures differ. Comparison of urinary metal concentrations, having adjusted for estimated airborne exposure, may provide an answer. METHODS: Men and women were recruited to a cohort study of workers in the welding and electrical trades (the Workers Health in Apprenticeship Trades-Metal working and Electrical [WHAT-ME study]). They completed a recruitment questionnaire and further questionnaires every 6 months for up to 5 years. At each follow-up, they gave details on employment and, if welding, answered trade-specific questionnaires. Urine samples were collected by mail. Welding exposure matrices were developed to estimate metal exposures from welding process, base metal, and consumables. Urinary metal concentrations, determined by ICP-MS, were compared by trade (welding or electrical). Within welding, the relation of urinary concentrations to estimated airborne exposure was examined, with adjustment for potential confounders including sex, use of respiratory protective equipment (RPE), and time spent outdoors. Natural logarithms were taken of exposure estimates and urinary concentrations, to reduce skew. All regression analyses included creatinine concentration. RESULTS: Urinary metal concentrations were analysed for 12 metals in 794 samples. Antimony, arsenic, lead, and mercury had a high proportion of samples with no metal detected and were not considered further. The urinary concentrations of aluminum, cadmium, chromium, cobalt, copper, manganese, nickel, and zinc were compared for welders (434 samples) and electrical workers (360). After adjustment for potential confounders, welders had higher urinary concentrations for aluminum (ß = 0.13 95%CI 0.03-0.24) and chromium (ß = 0.66 95%CI 0.55-0.77). Of 434 welder urines, 334 could be matched securely to detailed information about the most recent day welding. For these, an estimate of airborne exposure was made for aluminum, chromium, manganese, and nickel. Male welders were estimated to have higher airborne exposure to chromium and nickel than women welders. No difference was seen in the estimated exposures for aluminum or manganese (or total dust). Regression analyses of the relation of urinary metals to estimated exposure showed a good concordance for aluminum (ß = 0.09 95%CI 0.04-0.15 (P < 0.001) and chromium (ß = 0.11 95%CI 0.05-0.17 P < 0.001). The concordance for manganese and nickel was positive, but much weaker. Urinary concentrations of aluminum and nickel were somewhat lower with increasing time wearing RPE and, for chromium and nickel, with time working outdoors. Having adjusted for estimated exposure, creatinine and other confounders, male welders had lower urine concentrations of aluminum (ß = -0.35 95%CI -0.51 to -0.19 P < 0.001) chromium (ß = -0.38 95%CI -0.57 to -0.19 P < 0.001) and manganese (ß = -0.36 95%CI -0.49 to -0.23 P < 0.001) than female welders. CONCLUSION: Welders had higher urinary concentrations of aluminum and chromium than electrical workers. Exposure estimates of aluminum and chromium for welders were a valid representation of the airborne exposures to these metals. Although male welders were estimated to have higher exposures of chrome and nickel than female welders, the higher urinary metal concentrations in women welders is of concern, particularly for women who may conceive while in the trade.

Ergonomic demands and fetal loss in women in welding and electrical trades: A Canadian cohort study.

OBJECTIVES: To determine the relationship between ergonomic demands of the job at conception and fetal loss (miscarriage or stillbirth). METHODS: Women with a welding or electrical trade apprenticeship were identified across Canada for the Women's Health in Apprenticeship Trades-Metal and Electrical study. They completed a reproductive and employment history at recruitment and every 6 months for up to 5 years to provide details on pregnancies and work demands. Job at conception was identified and fetal loss examined in relation to ergonomic exposures/demands, allowing for potential confounders. RESULTS: A total of 885 women were recruited; 447 in welding and 438 in electrical trades. Of these, 574 reported at least one pregnancy. Analysis of 756 pregnancies since the woman started in her trade suggested no increased risk of fetal loss in those choosing welding rather than electrical work. Among 506 pregnancies conceived during a period working in a trade, 148 (29.2%) ended in fetal loss: 31.2% (73/234) in welding, and 27.6% (75/272) in electrical work. Detailed exposure information was available for 59% (299/506) of these pregnancies. In welders, the risk of fetal loss was increased with whole-body vibration (prevalence ratio [PR] = 2.14; 95% confidence interval [CI] 1.39-3.31) and hand-arm vibration for > 1 hour/day (PR = 2.15; 95% CI 1.33-3.49). In electrical workers risk increased with more than 8 days working without a rest day (PR = 2.29; 95% CI 1.25-4.17). Local exhaust ventilation reduced risk in welders. CONCLUSIONS: There was no significant increase in fetal loss in welding trades compared to electrical work. Vibration, largely from grinding, and extended work rotations appear to be potentially modifiable factors of some importance.

The Health of Firefighters Deployed to the Fort McMurray Fire: Lessons Learnt.

Introduction: Firefighters were working in exceptionally difficult conditions during the Fort McMurray/Horse River fire in May 2016. Methods: From mid-May, we recruited firefighters from 13 fire services as they returned from the fire. In October 2016 we extended recruitment to all Alberta-based firefighters deployed to the fire. In December 2017-May 2018 we sent a first online follow-up: this concentrated on mental health supports. The second follow-up, in October 2018-January 2019, included screening scales for respiratory ill-health and PTSD. All three contacts included visual analogue scales for chest symptoms and the Hospital Anxiety and Depression Scale. We estimated exposure to PM2.5, and calculated an exposure mitigation index from reports of respiratory protective equipment (RPE). Results: We recruited 1,234 firefighters and examined the relation of respiratory symptoms to estimated particulate exposure. The relation was strong immediately post fire but weakened over time. We found less chest tightness and cough in those whose RPE in the first week mitigated exposure by at least 10%. We examined the relation between particulate exposure and mental ill-health from screening questionnaires and found those with high exposure (reflecting the ferocity of the fire) had poorer mental health scores. Firefighters reporting their "worst moment during the fire" was life threatening were more anxious at second follow-up. Overall both anxiety and depression scores increased at successive contacts, more so in those with mental ill-health recorded in physician billing records before the fire. Discussion: The results from this study overall suggest on-going fire-related health effects in a substantial minority of firefighters, similar to those reported in the longitudinal follow-up of firefighters after the collapse of the World Trade Centre. Self-reports of both respiratory symptoms and mental ill-health were strongly related, soon after the fire, to estimated particulate exposures. Anxiety increased over time since the fire in those who felt their life or safety had been threatened, underlining the need for ongoing support. Our conclusions about the benefits of rapid research relate particularly to the collection of biomarkers of exposure as quickly and widely as possible, and the establishment of a nominal list of participants before they are too widely dispersed.

Respiratory Outcomes of Firefighter Exposures in the Fort McMurray Fire: A Cohort Study From Alberta Canada.

OBJECTIVE: Determine effects on respiratory health of firefighters attending a catastrophic wildfire. METHODS: Within the Alberta Administrative Health Database, we identified five community-based controls for each firefighter in a cohort of 1234 deployed to the 2016 Fort McMurray fire. Spirometry records were identified and a stratified sample assessed clinically. We estimated PM2.5 particles exposure. RESULTS: Firefighters had an increased risk of asthma consultation post-fire (OR new onset asthma = 2.56; 95%CI 1.75 to 3.74). Spirometry showed decreased FEV1 and FVC with increasing exposure. In the clinical assessment, 20% had a positive MCT and 21% BWT. Those with ongoing fire-related symptoms had a higher concurrence of positive MCT and BWT (OR = 4.35; 95%CI 1.11 to 17.12). Lower diffusion capacity related to higher exposure. CONCLUSIONS: Massive exposures during a wildfire are associated with non-resolving airways damage.

The role of organizational supports in mitigating mental ill health in firefighters: A cohort study in Alberta, Canada.

INTRODUCTION: Little is known about the effectiveness of ongoing mental health support in reducing the mental health impacts of a traumatic deployment. METHODS: A cohort of firefighters was established among those deployed to a devastating wildfire in Alberta, Canada in May 2016. Firefighters completed three questionnaires: at recruitment giving details of exposures, a first follow-up reporting mental health supports before, during, and after the fire and a second follow-up, at least 30 months after the fire, with screening questionnaires for anxiety, depression, and posttraumatic stress disorder (PTSD). Fire chiefs were interviewed about mental health provisions. The impact of supports on mental ill health was estimated, adjusting for clustering within fire service and potential confounders. RESULTS: Of 1234 firefighters in the cohort, 840 completed the questionnaire on mental health supports. In total, 78 of 82 fire chiefs were interviewed. Analysis of the impact of supports on mental ill health included 745 firefighters from 67 fire services. Only 45.8% of reports of peer support were concordant between firefighters and fire chiefs. After adjusting for confounding, the odds ratios (OR) for peer support reported by both fire chief and firefighter were depressive disorder: OR = 0.22, 95% confidence interval (CI), 0.08-0.61; anxiety disorder: OR = 0.45, 95% CI, 0.24-0.82; PTSD: OR = 0.62, 95% CI, 0.37-1.02. Symptoms of anxiety and depression but not PTSD were reduced by resiliency training before the fire and by support offered within 48 h of return from deployment. CONCLUSION: The results suggest peer support in firefighters is protective but its availability is poorly recognized. PTSD was somewhat less responsive, perhaps reflecting the cumulative effects of previous exposures.

Are Inflammatory Markers an Indicator of Exposure or Effect in Firefighters Fighting a Devastating Wildfire? Follow-up of a Cohort in Alberta, Canada.

OBJECTIVES: The Fort McMurray fire in Alberta, Canada, devastated the townsite in May 2016. First responders were heavily exposed to smoke particles. Blood samples taken from firefighters in May and August/September 2016 were used to measure concentrations of inflammatory markers in plasma and the relation of these markers to exposures and respiratory ill-health. METHODS: Blood samples were drawn from firefighters from two fire services, who also completed questionnaires about tasks and exposures during their deployment to the fire and about respiratory symptoms. Plasma was analysed for 42 inflammatory markers in a multiplex assay. At Service A, samples were collected twice, within 19 days of the start of the fire (early sample) and again 14-18 weeks later (late sample). At Service B, only late samples were collected, at 16-20 weeks. Principal component (PC) scores were extracted from markers in plasma from the early and late samples and, at both time periods, the first two components retained. PC scores were examined against estimated cumulative exposures to PM2.5 particles, self-rated physical stressors during the fire, and time since the last deployment to an active fire. The relation of component scores and exposure estimates to respiratory health were examined, using self-ratings at the time of the blood draw, a validated respiratory screening questionnaire (the European Community Respiratory Health Survey [ECRHS]) some 30 months after the fire, and clinical assessments in 2019-2020. RESULTS: Repeat blood samples were available for 68 non-smoking first responders from Service A and late samples from 160 non-smokers from both services. In the 68 with two samples, marker concentrations decreased from early to late samples for all but 3 of the 42 markers, significantly so (P < 0.05) for 25. The first component extracted from the early samples (C1E) was unrelated to respiratory symptoms but the second (C2E) was weakly related to increased cough (P = 0.079) and breathlessness (P = 0.068) and a lower forced expiratory volume in one second/forced expiratory capacity (FEV1/FVC)(ß = -1.63, 95% CI -3.11 to -0.14) P = 0.032. The first PC at 14-20 weeks (C1L) was unrelated to exposure or respiratory health but the second PC (C2L) from these late samples, drawn from both fire services, related to cumulative PM2.5 exposure. In a multivariate model, clustered within fire service, cumulative exposure (ß = 0.19, 95% CI 0.09-0.30), dehydration (ß = 0.65, 95% CI 0.04-1.27) and time since last deployed to a fire (ß = -0.04, 95% CI -0.06 to -0.01) were all related to the C2L score. This score was also associated with respiratory symptoms of wheezing, chest tightness, and breathlessness at the time of the blood draw but not to symptoms at later follow-up. However, apart from the lower FEV1/FVC at 15-19 days, the marker scores did not add to regression models that also included estimated cumulative PM2.5 exposure. CONCLUSIONS: Concentrations of persisting inflammatory markers in the plasma of firefighters deployed to a devastating fire decreased with time and were related to estimates of exposure. Although not a powerful independent predictor of later respiratory ill-health, they may serve as an indicator of previous high exposure in the absence of contemporary exposure estimates.

Occupational Dermatitis in Welding: Does Nickel Exposure Account for Higher Rates in Women? Analysis of a Canadian Cohort.

OBJECTIVES: Women are reported to have higher rates of nickel sensitization than men, but there have been few studies of sex-related differences in dermatitis associated with occupational nickel exposure. This analysis examines dermatitis in a large cohort of women and men in welding and electrical occupations and considers how far differences in rates of dermatitis may be accounted for by nickel exposure. METHODS: Women and men were recruited to cohorts of workers who had entered welding and electrical apprenticeships (the WHAT-ME and WHAT-MEN studies). Participants completed questionnaires at baseline and every 6 months for up to 5 years. At each contact, cohort members were asked about current dermatitis and whether it was made worse by work. From the first follow-up after recruitment, those working in their trade completed detailed subroutines about tasks in their trade including, for welders, the process, base metal, and consumables. Exposures were considered by trade and, within welding, by stainless or high alloy steel (SOHAS) as the base metal. Urinary nickel concentration was also examined. Using only report of dermatitis that began after entry to the trade, new-onset dermatitis, all episodes of dermatitis, and dermatitis made worse by work were examined against exposure by multilevel, multivariable logistic regression, allowing for potential confounding. RESULTS: Among 1885 participants (welders; 447 women, 554 men: electrical trades; 438 women, 446 men), 200 reported dermatitis that started before they entered the trade, leaving 1685 for analysis. Women, but not men, who had entered the welding trades were more at risk of new onset [odds ratio (OR) = 1.54; 95% confidence interval (CI) 1.02-2.32] or dermatitis episodes (OR = 1.75; 95% CI 1.10-2.77) than those entering the electrical trades. Within welding, women were more at risk than men of new-onset dermatitis (OR = 1.85; 95% CI 1.15-2.96) and dermatitis episodes (2.14; 95% CI 1.24-3.68) but were not more likely to report these were made worse by work. Use of SOHAS as the base metal was associated with reports that dermatitis was made worse by work (3.54; 95% CI 1.04-12.03), but having adjusted for SOHAS use, women still remained at greater risk. A final analysis considered the effect on risk estimates of removing those welding SOHAS from the analysis. The risk for women of episodes of dermatitis was essentially unchanged, whether the comparison group was male welders or women in the electrical trades. CONCLUSIONS: Welding is associated with risk of dermatitis in women. Although welding of SOHAS was associated with dermatitis that was made worse by work, it does not importantly explain the higher female rates in welding and other causes must be examined to support preventive measures.

Prevalence of Mental Ill-Health in a Cohort of First Responders Attending the Fort McMurray Fire.

OBJECTIVES: The study was designed to estimate the prevalence of mental disorders in a cohort of firefighters who had been deployed to a devastating fire in Fort McMurray, Alberta, in 2016. METHODS: A cohort of firefighters was established and followed up by online questionnaires. The contact in October 2018 to March 2019 included the PCL-5 questionnaire screening for post-traumatic stress disorder (PTSD) and the Hospital Anxiety and Depression Scale (HADS) screening for anxiety and depression. A sample was selected comprising all scoring ≥31 on the PCL-5 or ≥12 on either scale of the HADS, 30% of those scoring 8 to 11 on the HADS, and 10% of those with lower scores on all scales. This sample was assessed through a structured clinical interview to categorize disorders as defined in Diagnostic and Statistical Manual for Mental Disorders, fifth edition (DSM-5). Interviews were carried out face-to-face or by telephone between August 2019 and February 2020. Diagnoses in the interview sample were reweighted to obtain prevalence estimates for the whole cohort. In an analysis of receiver operating characteristics (ROC), possible cut points for scores from each screening questionnaire were examined. RESULTS: In 2018 to 2019, 1,000 of the cohort of 1,234 firefighters completed the HADS and 998 completed the PCL-5. Of these, 282 were identified for structured clinical interviews for DSM-5 (SCID) assessment. Interviews were carried out with 192. Among those assessed, 40.6% met the criteria for PTSD, 30.7% for an anxiety disorder, and 28.5% for a depressive disorder. When reweighted to allow for sampling and losses to assessment, cohort prevalence estimates were as follows: PTSD 21.4% (15.7% to 29.1%), anxiety disorders 15.8% (11.0% to 22.5%), and depressive disorders 14.3% (9.9% to 20.8%). Lower prevalence estimates were obtained when using the cut point with least misclassification in the ROC analysis. CONCLUSION: Using the gold-standard SCID assessment, high rates of mental disorders were found in this cohort of firefighters who had experienced a devastating fire. Fewer cases would have been identified by screening questionnaire alone.