Indoor exposure to ultrafine particles related to domestic activities: A systematic review and meta-analysis

Ultrafine particles (< 100 nm) are of increasing concern because of their toxicological potential. Emission processes suggest their presence in all environments, including at home, where particularly at-risk populations may be exposed. However, knowledge of their impact on health is still limited, due to difficulties in properly assessing exposure in epidemiological studies. In this context, the objective of this study was to provide a complete summary of indoor exposure to ultrafine particles in highly industrialised countries by examining the domestic activities that influence such exposure. We conducted a systematic review, according to PRISMA guidelines using PubMed, Web of Science and Scopus up to and including 2021. We carried out a qualitative and quantitative analysis of the selected studies with a standardised template. Exposure circumstances, measurement methods, and results were analysed. Finally, a meta-analysis of the measured concentrations was performed to study exposure levels during domestic activities. The review included 69 studies resulting in the analysis of 346 exposure situations. Nine main groups of activities were identified: cooking, which was the most studied, smoking, the use of air-fresheners, cleaning, heating, personal care, printing, do-it-yourself activities, and others. Over 50 different processes were involved in these activities. Based on available particle number concentrations, the highest average of mean concentrations was associated with grilling (14,400 × 103 cm-3), and the lowest with wood stove (18 × 103 cm-3). The highest average of peak concentrations was that for the use of hair dryers (695 × 103 cm-3), and the lowest for the use of air cleaners (11 × 103 cm-3). A hierarchy of domestic activities and related processes leading to ultrafine particle exposure is provided, along with average exposure concentrations at home. However, more extensive measurement campaigns are needed under real-life conditions to improve assessments of indoor exposure to ultrafine particles.

Pleural Plaques and the Role of Exposure to Mineral Particles in the Asbestos Post-Exposure Survey

BACKGROUND

Previous studies have inconsistently reported associations between refractory ceramic fibers (RCFs) or mineral wool fibers (MWFs) and the presence of pleural plaques (PPs). All these studies were based on chest radiographs, known to be associated with a poor sensitivity for the diagnosis of PP.

RESEARCH QUESTION

Does the risk of PPs increase with cumulative exposure to RCFs, MWFs, and silica? If the risk does increase, do these dose-response relationships depend on the co-exposure to asbestos or, conversely, are the dose-response relationships for asbestos modified by co-exposure to RCFs, MWFs, and silica?

STUDY DESIGN AND METHODS

Volunteer workers were invited to participate in a CT scan screening program for asbestos-related diseases in France. Asbestos exposure was assessed by industrial hygienists, and exposure to RCFs, MWFs, and silica was determined by using job-exposure matrices. A cumulative exposure index (CEI) was then calculated for each subject and separately for each of the four mineral particle exposures. All available CT scans were submitted to randomized, double reading by a panel of radiologists.

RESULTS

In this cohort of 5,457 subjects, significant dose-response relationships were determined after adjustment for asbestos exposure between CEI to RCF or MWF and the risk of PPs (ORs of 1.29 [95% CI, 1.00-1.67] and 1.84 [95% CI, 1.49-2.27] for the highest CEI quartile, respectively). Significant interactions were found between asbestos on one hand and MWF or RCF on the other.

INTERPRETATION

This study suggests the existence of a significant association between exposure to RCFs and MWFs and the presence of PPs in a large population previously exposed to asbestos and screened by using CT scans.

Pleural plaques and risk of lung cancer in workers formerly occupationally exposed to asbestos: extension of follow-up

BACKGROUND

Occupational asbestos exposure is associated with pleural plaques (PP), a benign disease often seen as a marker of past exposure to asbestos and lung cancer. The association between these two diseases has not been formally proved, the aim of this study was to evaluate this association in the asbestos-related disease cohort (ARDCO) cohort.

METHODS

ARDCO is a French multicentric cohort including workers formerly occupationally exposed to asbestos from 2003 to 2005. CT scan was performed to diagnose PP with double reading and lung cancer (incidence and mortality) was followed through health insurance data and death certificates. Cox models were used to estimate the association between PP and lung cancer adjusting for occupational asbestos exposure (represented by cumulative exposure index, time since first exposure and time since last exposure) and smoking status.

RESULTS

A total of 176 cases (of 5050 subjects) and 88 deaths (of 4938 subjects) of lung cancer were recorded. Smoking status was identified as an effect modifier. Lung cancer incidence and mortality were significantly associated with PP only in non-smokers, respectively, HR=3.13 (95% CI 1.04 to 9.35) and HR=16.83 (95% CI 1.87 to 151.24) after adjustment for age, occupational asbestos exposure and smoking status.

CONCLUSIONS

ARDCO study was the first to study this association considering equal asbestos exposure, and more specifically, our study is the first to test smoking as an effect modifier, so comparison with scientific literature is difficult. Our results seem to consolidate the hypothesis that PP may be an independent risk factor for lung cancer but they must be interpreted with caution.

Head and neck cancer and asbestos exposure

OBJECTIVES

The aim of this study was to analyse, within a French cohort of workers previously occupationally exposed to asbestos, incidence and mortality from various sites of head and neck cancers (larynx excluded) and to examine the potential link of these cancers with pleural plaques.

METHODS

A 10-year follow-up study was conducted in the 13 481 male subjects included in the cohort between October 2003 and December 2005. Asbestos exposure was assessed by industrial hygienist analysis of a standardised questionnaire. The final cumulative exposure index (CEI; in equivalent fibres.years/mL) for each subject was calculated as the sum of each employment period's four-level CEI. The number of head and neck cancers recorded by the National Health Insurance fund was collected in order to conduct an incidence study. Complementary analysis was restricted to men who had performed at least one chest CT scan (N=4804). A mortality study was also conducted. We used a Cox model with age as the time axis variable adjusted for smoking, time since first exposure, CEI of exposure to asbestos and pleural plaques on CT scans.

RESULTS

We reported a significant dose-response relationship between CEI of exposure to asbestos and head and neck cancers after exclusion of laryngeal cancers, in the mortality study (HR 1.03, 95% CI (1.01 to 1.06) for an increase of 10 f.years/mL) and a close to significant dose-response relationship in the incidence study (HR 1.02, 95% CI (1.00 to 1.04) for an increase of 10 f.years/mL). No statistically significant association between pleural plaques and head and neck cancer incidence was observed.

CONCLUSIONS

This large-scale study suggests a relationship between asbestos exposure and head and neck cancers, after exclusion of laryngeal cancers, regardless of whether associated pleural plaques were present.

Overall and net survival of patients with sarcoma between 2005 and 2010: Results from the French Network of Cancer Registries (FRANCIM)

BACKGROUND

Sarcomas are rare, heterogeneous, ubiquitously localized malignancies with many histologic subtypes and genomic patterns. The survival of patients with sarcoma has rarely been described based on this heterogeneity; therefore, the authors' objective was to estimate survival outcomes in patients who had sarcomas using the 2020 version of the World Health Organization classification of soft tissue and bone tumors.

METHODS

Patients older than 15 years who had incident sarcoma diagnosed between 2005 and 2010 were extracted from 14 French population-based cancer registries covering 18% of the French metropolitan population. Vital status for each patient was actively followed up to June 30, 2013. Net survival (NS) was estimated using the unbiased Pohar-Perme method.

RESULTS

Overall, 4202 patients were included. NS declined with increasing age at diagnosis. According to topographic groups, large 5-year NS disparities were observed, ranging from 47% among women with gynecologic sarcomas to 89% among patients with skin sarcomas. Patients with soft tissue, bone, and gastrointestinal sarcomas had 5-year NS rates of 53%, 61%, and 70%, respectively. Similar heterogeneity was observed according to histologic subtypes, with 5-year NS ranging from 19% for patients with angiosarcomas to 96% for patients with dermatofibrosarcomas. Patients with sarcoma who displayed missense mutations had a better 5-year NS (74%); those with MDM2-amplified sarcomas had the worst NS (45%).

CONCLUSIONS

NS rates in patients with sarcoma are presented here for the first time based on the 2020 World Health Organization classification applied to population-based registry data. Large prognostic heterogeneity was observed based on age, topographic and histologic groups, and genomic alteration profiles, constituting a benchmark for future studies and clinical trials.

Deep Learning for the Automatic Quantification of Pleural Plaques in Asbestos-Exposed Subjects

Objective: This study aimed to develop and validate an automated artificial intelligence (AI)-driven quantification of pleural plaques in a population of retired workers previously occupationally exposed to asbestos. Methods: CT scans of former workers previously occupationally exposed to asbestos who participated in the multicenter APEXS (Asbestos PostExposure Survey) study were collected retrospectively between 2010 and 2017 during the second and the third rounds of the survey. A hundred and forty-one participants with pleural plaques identified by expert radiologists at the 2nd and the 3rd CT screenings were included. Maximum Intensity Projection (MIP) with 5 mm thickness was used to reduce the number of CT slices for manual delineation. A Deep Learning AI algorithm using 2D-convolutional neural networks was trained with 8280 images from 138 CT scans of 69 participants for the semantic labeling of Pleural Plaques (PP). In all, 2160 CT images from 36 CT scans of 18 participants were used for AI testing versus ground-truth labels (GT). The clinical validity of the method was evaluated longitudinally in 54 participants with pleural plaques. Results: The concordance correlation coefficient (CCC) between AI-driven and GT was almost perfect (>0.98) for the volume extent of both PP and calcified PP. The 2D pixel similarity overlap of AI versus GT was good (DICE = 0.63) for PP, whether they were calcified or not, and very good (DICE = 0.82) for calcified PP. A longitudinal comparison of the volumetric extent of PP showed a significant increase in PP volumes (p < 0.001) between the 2nd and the 3rd CT screenings with an average delay of 5 years. Conclusions: AI allows a fully automated volumetric quantification of pleural plaques showing volumetric progression of PP over a five-year period. The reproducible PP volume evaluation may enable further investigations for the comprehension of the unclear relationships between pleural plaques and both respiratory function and occurrence of thoracic malignancy.

Interstitial Lung Abnormalities Detected by CT in Asbestos-Exposed Subjects Are More Likely Associated to Age

Objective: the aim of this study was to evaluate the association between interstitial lung abnormalities, asbestos exposure and age in a population of retired workers previously occupationally exposed to asbestos. Methods: previously occupationally exposed former workers to asbestos eligible for a survey conducted between 2003 and 2005 in four regions of France, underwent chest CT examinations and pulmonary function testing. Industrial hygienists evaluated asbestos exposure and calculated for each subject a cumulative exposure index (CEI) to asbestos. Smoking status information was also collected in this second round of screening. Expert radiologists performed blinded independent double reading of chest CT-scans and classified interstitial lung abnormalities into: no abnormality, minor interstitial findings, interstitial findings inconsistent with UIP, possible or definite UIP. In addition, emphysema was assessed visually (none, minor: emphysema <25%, moderate: between 25 and 50% and severe: >50% of the lung). Logistic regression models adjusted for age and smoking were used to assess the relationship between interstitial lung abnormalities and occupational asbestos exposure. Results: the study population consisted of 2157 male subjects. Interstitial lung abnormalities were present in 365 (16.7%) and emphysema in 444 (20.4%). Significant positive association was found between definite or possible UIP pattern and age (OR adjusted =1.08 (95% CI: 1.02–1.13)). No association was found between interstitial abnormalities and CEI or the level of asbestos exposure. Conclusion: presence of interstitial abnormalities at HRCT was associated to aging but not to cumulative exposure index in this cohort of former workers previously occupationally exposed to asbestos.

Development of a Job-Exposure Matrix for Ultrafine Particle Exposure: The MatPUF JEM

OBJECTIVE

Ultrafine particles (UFPs) are generated from common work processes and have thus existed for a long time. Far more prevalent than engineered nanoparticles, they share common toxicological characteristics with them. However, there is no existing retrospective assessment tool specific to UFPs, for example, for epidemiological purposes. Thus, we aimed to develop a job-exposure matrix dedicated to UFPs.

METHOD

Fifty-seven work processes were identified as well as the chemical composition of UFPs emitted, following a literature review and the input of an expert panel. These work processes were associated with occupational codes as defined by the ISCO 1968 classification. The probability and frequency of UFP exposure were assessed for each combination of occupational code and process. Summarized probabilities and frequencies were then calculated for all ISCO occupational codes associated with several processes. Variations in exposure over time or across industrial sectors were accounted for in the assessment of each occupational code.

RESULTS

In the ISCO classification, 52.8% of the occupational codes (n = 835) assessed were associated with exposure to UFPs, consisting mainly of carbonaceous, metallic, and mineral families (39.5%, 22 and, 15.8%, respectively). Among them, 42.6% involved very probable exposure, and at a high frequency (regularly or continuously).

CONCLUSION

These results suggest that occupational exposure to UFPs may be extensive at the workplace and could concern a wide variety of workers. Pending the integration of a third parameter assessing the intensity of UFP exposure, the MatPUF JEM already constitutes a promising and easy-to-use tool to study the possible adverse health effects of UFPs at work. It may also guide prevention policies in the occupational environments concerned, including those involving engineered nanoparticles.

ERS/ESTS/EACTS/ESTRO guidelines for the management of malignant pleural mesothelioma

The European Respiratory Society (ERS)/European Society of Thoracic Surgeons (ESTS)/European Association for Cardio-Thoracic Surgery (EACTS)/European Society for Radiotherapy and Oncology (ESTRO) task force brought together experts to update previous 2009 ERS/ESTS guidelines on management of malignant pleural mesothelioma (MPM), a rare cancer with globally poor outcome, after a systematic review of the 2009-2018 literature. The evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluation approach. The evidence syntheses were discussed and recommendations formulated by this multidisciplinary group of experts. Diagnosis: pleural biopsies remain the gold standard to confirm the diagnosis, usually obtained by thoracoscopy but occasionally via image-guided percutaneous needle biopsy in cases of pleural symphysis or poor performance status. Pathology: standard staining procedures are insufficient in ∼10% of cases, justifying the use of specific markers, including BAP-1 and CDKN2A (p16) for the separation of atypical mesothelial proliferation from MPM. Staging: in the absence of a uniform, robust and validated staging system, we advise using the most recent 2016 8th TNM (tumour, node, metastasis) classification, with an algorithm for pretherapeutic assessment. Monitoring: patient's performance status, histological subtype and tumour volume are the main prognostic factors of clinical importance in routine MPM management. Other potential parameters should be recorded at baseline and reported in clinical trials. Treatment: (chemo)therapy has limited efficacy in MPM patients and only selected patients are candidates for radical surgery. New promising targeted therapies, immunotherapies and strategies have been reviewed. Because of limited data on the best combination treatment, we emphasize that patients who are considered candidates for a multimodal approach, including radical surgery, should be treated as part of clinical trials in MPM-dedicated centres.

Occupational exposure to unintentionally emitted nanoscale particles and risk of cancer: From lung to central nervous system - Results from three French case-control studies

OBJECTIVES

Nanoscale particles (1-100 nm) can be of natural origin, and either intentionally or unintentionally produced by human activities. Toxicological data have suggested a possible carcinogenic effect of such particles. The aim of this study was to estimate the association between occupational exposure to nanoscale particles and risk of lung cancer, pleural mesothelioma and brain tumors in adults.

METHODS

Three French population-based case-control studies were analyzed: 1) the ICARE study including 2029 lung cancer cases and 2591 controls; 2) the PNSM study including 371 pleural mesothelioma cases and 730 controls and 3) the CERENAT study including 257 brain tumor cases and 511 controls. Occupational exposure to unintentionally emitted nanoscale particles (UNPs) was retrospectively assessed by a job exposure matrix providing a probability and a frequency of exposure.

RESULTS

In adjusted analyses among men, significant associations between occupational exposure to UNPs and lung cancer (OR = 1.51; 95% CI: 1.22-1.86 and brain tumors (OR = 1.69; 95% CI: 1.17-2.44) were observed. No increased OR was observed for pleural mesothelioma (OR = 0.78; 95% CI: 0.46-1.33).

CONCLUSION

This is the first study showing positive associations between occupational exposure to UNPs and increased risk of lung cancer and brain tumors. These preliminary results should encourage further epidemiological research.

What does ergonomics have to do with nanotechnologies? A case study

Despite recent concerns for workers' health, exposure situations to nanoparticles can occur in numerous workplaces. Understanding how exposures occur considering human work in these transformations remains a crucial issue of nanotechnologies. The objective of this article is to understand exposure situations to nanoparticles, their determinants and the resources to act on them. This understanding was achieved by specific measurement of nanoparticles aerosols, combined with an analysis of work activity (actions performed and physical strain) in a rubber industry. The presentation of real time measurements, associated with the video of work situations, during confrontation interviews becomes a means of making exposing work activities visible, to analyze and transform them from the points of view formulated by the company's stakeholders. In this way, characterized "typical exposure situations" serve to trigger discussions and open up new spaces for debate highlighting how innovation affects work and gives rise to enhanced prevention projects.

ERS/ESTS/EACTS/ESTRO guidelines for the management of malignant pleural mesothelioma

The European Respiratory Society (ERS)/European Society of Thoracic Surgeons (ESTS)/European Association for Cardio-Thoracic Surgery (EACTS)/European Society for Radiotherapy and Oncology (ESTRO) task force brought together experts to update previous 2009 ERS/ESTS guidelines on management of malignant pleural mesothelioma (MPM), a rare cancer with globally poor outcome, after a systematic review of the 2009-2018 literature. The evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluation approach. The evidence syntheses were discussed and recommendations formulated by this multidisciplinary group of experts. Diagnosis: pleural biopsies remain the gold standard to confirm the diagnosis, usually obtained by thoracoscopy but occasionally via image-guided percutaneous needle biopsy in cases of pleural symphysis or poor performance status. Pathology: standard staining procedures are insufficient in ∼10% of cases, justifying the use of specific markers, including BAP-1 and CDKN2A (p16) for the separation of atypical mesothelial proliferation from MPM. Staging: in the absence of a uniform, robust and validated staging system, we advise using the most recent 2016 8th TNM (tumour, node, metastasis) classification, with an algorithm for pre-therapeutic assessment. Monitoring: patient's performance status, histological subtype and tumour volume are the main prognostic factors of clinical importance in routine MPM management. Other potential parameters should be recorded at baseline and reported in clinical trials. Treatment: (chemo)therapy has limited efficacy in MPM patients and only selected patients are candidates for radical surgery. New promising targeted therapies, immunotherapies and strategies have been reviewed. Because of limited data on the best combination treatment, we emphasise that patients who are considered candidates for a multimodal approach, including radical surgery, should be treated as part of clinical trials in MPM-dedicated centres.

Maternal occupational exposure to carbonaceous nanoscale particles and small for gestational age and the evolution of head circumference in the French Longitudinal Study of Children - Elfe study

OBJECTIVES

To investigate the association between exposure to unintentionally emitted carbonaceous nanoscale particles (NPs) and small for gestational age (SGA), as well as head circumference (HC) at birth and at two years of age.

METHODS

Mothers from the French Longitudinal Study of Children (Elfe cohort) who worked during pregnancy were selected for our study. Data collected at birth and during follow-up (up to two years) were used. The probability and frequency of maternal occupational exposure to unintentionally emitted carbonaceous NPs was estimated using a job exposure matrix (MatPUF). Multivariate logistic regression, linear regression, and mixed models were applied to estimate any associations. Analyses were carried out depending on whether mothers stopped working during the first, second, or third trimester of pregnancy.

RESULTS

Maternal occupational exposure to unintentionally emitted carbonaceous NPs was associated with SGA in the overall study population by multivariate analysis (ORa = 1.80, 95% CI: 1.29, 2.46), as well as in sub-groups of mothers who stopped working during the second (ORa = 1.84, 95% CI: 1.13, 3.02) or third (ORa = 1.80, 95% CI: 1.10, 2.95) trimesters. There were no significant associations with HC at birth or two years of age.

CONCLUSIONS

We found a significant association between occupational exposure to carbonaceous NPs and SGA, with the effect depending on the period of exposure during pregnancy. These results should encourage further studies concerning the adverse effects of exposure to carbonaceous NPs on the development of offspring.

Incidence and time trends of sarcoma (2000-2013): results from the French network of cancer registries (FRANCIM)

BACKGROUND

The exhaustive collection of new sarcoma cases and their second histologic review offer a unique opportunity to study their incidence and time trends in France according to the major subtypes.

METHODS

Data were collected from population-based cancer registries covering 22% of the French population. Crude and world age-standardized incidence rates (ASR) were estimated according to anatomic, histological and genetic groups, age and sex over the 2010-2013 period.

RESULTS

Time trends in incidence were calculated by the annual percent change over the 2000-2013 period. During the most recent period (2010-2013), 3942 patients with sarcoma were included. The ASR of soft-tissue and bone sarcomas, and gastro-intestinal stromal tumors (GIST) were 2.1, 1.0 and 0.6, respectively. For the four most frequent histological subtypes (unclassified, leiomyosarcoma, GIST and liposarcoma), the ASR ranged from 0.4 to 0.7. ASRs were 1.9 for complex genomic and 1.3 for recurrent translocation sarcomas. The time-trend analysis showed a significant increase of sarcoma incidence rate between 2000 and 2005, which stabilized thereafter. Incidence rates increased for four histological subtypes (GIST, chondrosarcoma, myxofibrosarcoma, solitary fibrous tumors) and decreased for three (leiomyosarcomas, Kaposi sarcoma and fibrosarcoma).

CONCLUSION

To our knowledge, this study is the first to investigate sarcoma incidence based on a systematic pathological review of these cancers and on the updated sarcoma classifications. Due to the paucity of literature on sarcomas, future studies using data from population-based cancer registries should consider a standardized inclusion criterion presented in our study to better describe and compare data between countries.

ETIOSARC study : environmental aetiology of sarcomas from a French prospective multicentric population-based case-control study-study protocol

INTRODUCTION

Sarcomas are rare tumours of connective tissue. The exact overall incidence of sarcomas is unknown due to diagnostic difficulties and the various histological subtypes (over 80 subtypes). However, the apparent increasing incidence of sarcomas suggests environmental causes such as pesticides. Except for some specific factors (ie, ionising radiation, vinyl chloride, dioxin and genetic predispositions) the scientific knowledge on the aetiology of sarcomas is sparse and inconsistent. France is a particularly appropriate country to set up a study investigating the causes of sarcoma occurrence due to the French organisation in treatment and care of sarcoma patients, which is highly structured and revolved around national expert networks. The main objective of the ETIOlogy of SARcomas (ETIOSARC) project is to study the role of lifestyle, environmental and occupational factors in the occurrence of sarcomas among adults from a multicentric population-based case-control study.

METHODS AND ANALYSIS

Cases will be all incident patients (older than 18 years) prospectively identified in 15 districts of France covered by a general population-based cancer registry and/or a reference centre in sarcoma's patient care over a 3-year period with an inclusion start date ranging from February 2019 to January 2020 and histologically confirmed by a second review of the diagnosis. Two controls will be individually matched by sex, age (5 years group) and districts of residence and randomly selected from electoral rolls. A standardised questionnaire will be administered by a trained interviewer in order to gather information about occupational and residential history, demographic and socioeconomic characteristics and lifestyle factors. At the end of the interview, a saliva sample will be systematically proposed. This study will permit to validate or identify already suspected risk factors for sarcomas such as phenoxyherbicides, chlorophenol and to generate new hypothesis to increase our understanding about the genetic and environmental contributions in the carcinogenicity process.

ETHICS AND DISSEMINATION

The present study is promoted by the French National Institute of Health and Medical Research (identification number C17-03). This study received National French Ethic committee (CPP Sud Méditerrannée I) approval (identification number 18-31) and French Data Protection Authority (CNIL) approval (identification number 918171). Results of this study will be published in international peer-reviewed journals. Technical appendix, statistical code and dataset will be available in the Dryad repository when collection data are completed.

TRIAL REGISTRATION NUMBER

NCT03670927.

LUCSO-1-French pilot study of LUng Cancer Screening with low-dose computed tomography in a smokers population exposed to Occupational lung carcinogens: study protocol

INTRODUCTION

Guidelines concerning the follow-up of subjects occupationally exposed to lung carcinogens, published in France in 2015, recommended the setting up of a trial of low-dose chest CT lung cancer screening in subjects at high risk of lung cancer.

OBJECTIVE

To evaluate the organisation of low-dose chest CT lung cancer screening in subjects occupationally exposed to lung carcinogens and at high risk of lung cancer.

METHODS AND ANALYSIS

This trial will be conducted in eight French departments by six specialised reference centres (SRCs) in occupational health. In view of the exploratory nature of this trial, it is proposed to test initially the feasibility and acceptability over the first 2 years in only two SRCs then in four other SRCs to evaluate the organisation. The target population is current or former smokers with more than 30 pack-years (who have quit smoking for less than 15 years), currently or previously exposed to International Agency for Research on Cancer group 1 lung carcinogens, and between the ages of 55 and 74 years. The trial will be conducted in the following steps: (1) identification of subjects by a screening invitation letter; (2) evaluation of occupational exposure to lung carcinogens; (3) evaluation of the lung cancer risk level and verification of eligibility; (4) screening procedure: annual chest CT scans performed by specialised centres and (5) follow-up of CT scan abnormalities.

ETHICS AND DISSEMINATION

This protocol study has been approved by the French Committee for the Protection of Persons. The results from this study will be submitted to peer-reviewed journals and reported at suitable national and international meetings.

TRIAL REGISTRATION NUMBER

NCT03562052; Pre-results.

Maternal occupational exposures to nanoscale particles and small for gestational age outcome in the French Longitudinal Study of Children

OBJECTIVES

To investigate the association between maternal occupational exposures to nanoscale particles (NPs) during pregnancy and small for gestational age (SGA).

METHODS

This study included 11,224 mothers and singleton birth pairs from the French Longitudinal Study of Children (ELFE cohort), which included infants born after 33 weeks of gestation or more in continental France in 2011. Mothers who did not work during pregnancy were excluded from the analyses. Maternal occupational exposures to NPs was estimated using a job-exposure matrix for the probability (>50%: occupationally exposed group, n = 569; 0%: occupationally non-exposed group, n = 9113; between these two thresholds: uncertain group, n = 1542) and frequency of exposure. Associations were estimated from multivariate logistic regression models for occupationally exposed vs occupationally unexposed groups in a first analysis, and with the frequency-weighted duration of work for the occupationally exposed group only in a second analysis.

RESULTS

Among working mothers, 5.1% were occupationally exposed to NPs. Maternal occupational exposures to NPs was associated with SGA (ORa = 1.63, 95% CI: 1.22, 2.18). The frequency-weighted duration of work for the occupationally exposed group (n = 569) was not associated with SGA (ORa = 1.02, 95% CI: 0.97, 1.08) in adjusted analyses.

CONCLUSIONS

These results, showing a significant association between occupational exposures to NPs and SGA, should encourage further studies to examine the adverse effect of NPs exposure on fetal development.

Agreement in Occupational Exposures Between Men and Women Using Retrospective Assessments by Expert Coders

Objectives

To estimate the level of agreement and identify notable differences in occupational exposures (agents) between men and women from retrospective assessments by expert coders.

Methods

Lifetime occupational histories of 1657 men and 2073 women from two case-control studies, were translated into exposure estimates to 243 agents, from data on 13882 jobs. Exposure estimates were summarized as proportions and frequency-weighted intensity of exposure for 59 occupational codes by sex. Agreement between metrics of exposure in men's and women's jobs was determined with intraclass correlation coefficients (ICC) and weighted Kappa coefficients, using as unit of analysis ('cell') a combination of occupational code and occupational agent. 'Notable' differences between men and women were identified for each cell, according to a Bayesian hierarchical model for both proportion and frequency-weighted intensity of exposure.

Results

For cells common to both men and women, the ICC for continuous probability of exposure was 0.84 (95% CI: 0.83-0.84) and 7.4% of cells showed notable differences with jobs held by men being more often exposed. A weighted kappa of 0.67 (95% CI: 0.61-0.73) was calculated for intensity of exposure, and an ICC of 0.67 (95% CI: 0.62-0.71) for frequency-weighted intensity of exposure, with a tendency of higher values of exposure metrics in jobs held by men.

Conclusions

Exposures were generally in agreement between men and women. Some notable differences were identified, most of them explained by differential sub-occupations or industries or dissimilar reported tasks within the studied occupations.

Development of and Selected Performance Characteristics of CANJEM, a General Population Job-Exposure Matrix Based on Past Expert Assessments of Exposure

Objectives

We developed a job-exposure matrix called CANJEM using data generated in population-based case-control studies of cancer. This article describes some of the decisions in developing CANJEM, and some of its performance characteristics.

Methods

CANJEM is built from exposure information from 31673 jobs held by study subjects included in our past case-control studies. For each job, experts had evaluated the intensity, frequency, and likelihood of exposure to a predefined list of agents based on jobs histories and descriptions of tasks and workplaces. The creation of CANJEM involved a host of decisions regarding the structure of CANJEM, and operational decisions regarding which parameters to present. The goal was to produce an instrument that would provide great flexibility to the user. In addition to describing these decisions, we conducted analyses to assess how well CANJEM covered the range of occupations found in Canada.

Results

Even at quite a high level of resolution of the occupation classifications and time periods, over 90% of the recent Canadian working population would be covered by CANJEM. Prevalence of exposure of specific agents in specific occupations ranges from 0% to nearly 100%, thereby providing the user with basic information to discriminate exposed from unexposed workers. Furthermore, among exposed workers there is information that can be used to discriminate those with high exposure from those with low exposure.

Conclusions

CANJEM provides good coverage of the Canadian working population and possibly that of several other countries. Available in several occupation classification systems and including 258 agents, CANJEM can be used to support exposure assessment efforts in epidemiology and prevention of occupational diseases.

Time-dependent effect of intensity of smoking and of occupational exposure to asbestos on the risk of lung cancer: results from the ICARE case-control study

OBJECTIVE

To estimate the impact of intensity of both smoking and occupational exposure to asbestos on the risk of lung cancer throughout the whole exposure history.

METHODS

Data on 2026 male cases and 2610 male controls came from the French ICARE (Investigation of occupational and environmental causes of respiratory cancers) population-based, case-control study. Lifetime smoking history and occupational history were collected from standardised questionnaires and face-to-face interviews. Occupational exposure to asbestos was assessed using a job exposure matrix. The effects of annual average daily intensity of smoking (reported average number of cigarettes smoked per day) and asbestos exposure (estimated average daily air concentration of asbestos fibres at work) were estimated using a flexible weighted cumulative index of exposure in logistic regression models.

RESULTS

Intensity of smoking in the 10 years preceding diagnosis had a much stronger association with the risk of lung cancer than more distant intensity. By contrast, intensity of asbestos exposure that occurred more than 40 years before diagnosis had a stronger association with the risk of lung cancer than more recent intensity, even if intensity in the 10 years preceding diagnosis also had a significant effect.

CONCLUSION

Our results illustrate the dynamic of the effect of intensity of both smoking and occupational exposure to asbestos on the risk of lung cancer. They confirm that the timing of exposure plays an important role, and suggest that standard analytical methods assuming equal weights of intensity over the whole exposure history may be questionable.

Maternal cumulative exposure to extremely low frequency electromagnetic fields and pregnancy outcomes in the Elfe cohort

OBJECTIVES

To study the relations between maternal cumulative exposure to extremely low frequency electromagnetic fields (ELF EMF) and the risk of moderate prematurity and small for gestational age within the Elfe cohort.

METHODS

The Elfe study included 18,329 infants born at 33weeks of gestation or more in France in 2011 and was designed to follow the children until 20years of age. Gestational age and anthropometric data at birth were collected in medical records and small for gestational age was defined according to a French customized growth standard. During interviews, mothers were asked to report their job status during pregnancy. If employed, their occupation was coded according to the International Standard Classification of Occupations 1988 and the date on which they stopped their work was recorded. Cumulative exposure to ELF EMF during pregnancy was assessed, for both mothers who worked and those who did not during pregnancy, using a recently-updated job-exposure matrix (JEM). Cumulative exposure was considered as a categorical variable (<17.5, 17.5-23.8, 23.8-36.2, 36.2-61.6 or ≥61.6μT-days), a binary variable (<44.1 and ≥44.1μT-days) and a continuous variable. Associations were analyzed by logistic regression, adjusting for the mother's lifestyle factors, sociodemographic characteristics and some mother's medical history during and before pregnancy. Analyses were restricted to single births and to complete values for the pregnancy outcomes (n=16,733).

RESULTS

Cumulative exposure was obtained for 96.0% of the mothers. Among them, 37.5% were classified in the 23.8-36.2μT-days category, but high exposures were rare: 1.3% in the ≥61.6μT-days category and 5.5% in the ≥44.1μT-days category. No significant association was observed between maternal cumulative exposure and moderate prematurity and small for gestational age in this exposure range.

CONCLUSION

This large population-based study does not suggest that maternal exposure to ELF EMF during pregnancy is highly associated with risks of moderate prematurity or small for gestational age.

Prevalence of occupational exposure to asbestos and crystalline silica according to phenotypes of lung cancer from the CaProMat study: A case-only study

BACKGROUND

The objective of the study was to compare the prevalence of occupational exposure to asbestos and crystalline silica according to histological types of lung cancer and age at diagnosis.

METHODS

CaProMat study is a pooled case-only study conducted between 1996 and 2011. The current study consisted of 6521 lung cancer cases. Occupational exposure to asbestos and crystalline silica was assessed by two Job-Exposure Matrices. A weighted prevalence of exposure was derived and compared according to histological types and age at diagnosis.

RESULTS

There was no difference of weighted prevalence of exposure to asbestos and crystalline silica according to histological types of lung cancer. There was a statistically significant difference of weighted prevalence of exposure to asbestos and crystalline silica according to age at diagnosis.

CONCLUSIONS

Due to the limited clinical importance of the difference, neither the histological type, nor the age at diagnosis can be used as an indicator for the occupational exposure to asbestos or crystalline silica.

Cancer of the esophagus and asbestos exposure

BACKGROUND

Our study aimed at analyzing incidence and mortality from esophageal cancer within a cohort of workers with previous occupational asbestos exposure (ARDCo Program).

METHODS

A 10-year follow-up study was conducted in the 14 515 male subjects included in this program between October 2003 and December 2005. Follow-up began when exposure stopped. Asbestos exposure was analyzed by industrial hygienists using data from a standardized questionnaire. The Cox model was used, with age as the time axis variable adjusted for smoking, time since first exposure (TSFE) and cumulative exposure index (CEI) of exposure to asbestos.

RESULTS

We reported a significant dose-response relationship between CEI of exposure to asbestos and esophageal cancer, in both incidence (hazard ratio [HR] 1.26, 95% confidence interval [CI] 1.00-1.58), and mortality (HR 1.40, [95%CI 1.12-1.75]).

CONCLUSIONS

This large-scale study suggests the existence of a relationship between asbestos exposure and cancer of the esophagus.

Occupational Asbestos Exposure and Incidence of Colon and Rectal Cancers in French Men: The Asbestos-Related Diseases Cohort (ARDCo-Nut)

BACKGROUND

The relationships between asbestos exposure and colorectal cancer remain controversial.

OBJECTIVES

We examined the association between asbestos exposure and colorectal cancer incidence.

METHODS

Volunteer retired workers previously exposed to asbestos were invited to participate in the French ARDCo screening program between 2003 and 2005. Additional data on risk factors for colorectal cancer were collected from the ARDCo-Nut subsample of 3,769 participants in 2011. Cases of colon and rectal cancer were ascertained each year through 2014 based on eligibility for free medical care following a cancer diagnosis. Survival regression based on the Cox model was used to estimate the relative risk of colon and rectal cancer separately, in relation to the time since first exposure (TSFE) and cumulative exposure index (CEI) to asbestos, and with adjustment for smoking in the overall cohort and for smoking, and certain risk factors for these cancers in the ARDCo-Nut subsample.

RESULTS

Mean follow-up was 10.2 years among 14,515 men, including 181 colon cancer and 62 rectal cancer cases (41 and 17, respectively, in the ARDCo-Nut subsample). In the overall cohort, after adjusting for smoking, colon cancer was significantly associated with cumulative exposure (HR = 1.14; 95% CI: 1.04, 1.26 for a 1-unit increase in ln-CEI) and ≥ 20-40 years since first exposure (HR = 4.67; 95% CI: 1.92, 11.46 vs. 0-20 years TSFE), and inversely associated with 60 years TSFE (HR = 0.26; 95% CI: 0.10, 0.70). Although rectal cancer was also associated with TSFE 20-40 years (HR = 4.57; 95% CI: 1.14, 18.27), it was not associated with ln-CEI, but these findings must be interpreted cautiously due to the small number of cases.

CONCLUSIONS

Our findings provide support for an association between occupational exposure to asbestos and colon cancer incidence in men. Citation: Paris C, Thaon I, Hérin F, Clin B, Lacourt A, Luc A, Coureau G, Brochard P, Chamming's S, Gislard A, Galan P, Hercberg S, Wild P, Pairon JC, Andujar P. 2017. Occupational asbestos exposure and incidence of colon and rectal cancers in French men: the Asbestos-Related Diseases Cohort (ARDCo-Nut). Environ Health Perspect 125:409-415; http://dx.doi.org/10.1289/EHP153.

Absence of multiplicative interactions between occupational lung carcinogens and tobacco smoking: a systematic review involving asbestos, crystalline silica and diesel engine exhaust emissions

BACKGROUND

Tobacco smoking is the main cause of lung cancer, but it is not the sole causal factor. Significant proportions of workers are smokers and exposed to occupational lung carcinogens. This study aims to systematically review the statistical interaction between occupational lung carcinogens and tobacco smoking, in particular asbestos, crystalline silica and diesel engine exhaust emissions.

METHODS

Articles were identified using Scopus, PubMed, and Web of Science, and were limited to those published in English or French, without limitation of time. The reference list of selected studies was reviewed to identify other relevant papers. One reviewer selected the articles based on the inclusion and exclusion criteria. Two reviewers checked the eligibility of articles to be included in the systematic review. Data were extracted by one reviewer and revised by two other reviewers. Cohorts and case-control studies were analyzed separately. The risk of bias was evaluated for each study based on the outcome. The results of the interaction between the tobacco smoking and each carcinogen was evaluated and reported separately.

RESULTS

Fifteen original studies were included for asbestos-smoking interaction, seven for silica-smoking interaction and two for diesel-smoking interaction. The results suggested the absence of multiplicative interaction between the three occupational lung carcinogens and smoking. There is no enough evidence from the literature to conclude for the additive interaction. We believe there is a limited risk of publication bias as several studies reporting negative results were published.

CONCLUSION

There are no multiplicative interactions between tobacco smoking and occupational lung carcinogens, in particular asbestos, crystalline silica and diesel engine exhaust emissions. Even though, specific programs should be developed and promoted to reduce concomitantly the exposure to occupational lung carcinogens and tobacco smoking.

Five years update on relationships between malignant pleural mesothelioma and exposure to asbestos and other elongated mineral particles

Despite the reduction of global asbestos consumption and production due to the ban or restriction of asbestos uses in more than 50 countries since the 1970s, malignant mesothelioma remains a disease of concern. Asbestos is still used, imported, and exported in several countries, and the number of mesothelioma deaths may be expected to increase in the next decades in these countries. Asbestos exposure is the main risk factor for malignant pleural mesothelioma, but other types of exposures are linked to the occurrence of this type of cancer. Although recent treatments improve the quality of life of patients with mesothelioma, malignant pleural mesothelioma remains an aggressive disease. Recent treatments have not resulted in appreciable improvement in survival, and thus development of more efficient therapies is urgently needed. The development of novel therapeutic strategies is dependent on our level of knowledge of the physiopathological and molecular changes that mesothelial cells acquired during the neoplastic process. During the past 5 years, new findings have been published on the etiology, epidemiology, molecular changes, and innovative treatments of malignant pleural mesothelioma. This review aims to update the findings of recent investigations on etiology, epidemiology, and molecular changes with a focus on (1) attributable risk of asbestos exposure in men and women and (2) coexposure to other minerals and other elongated mineral particles or high aspect ratio nanoparticles. Recent data obtained on genomic and gene alterations, pathways deregulations, and predisposing factors are summarized.

Lung cancer risk among workers in the construction industry: results from two case-control studies in Montreal

BACKGROUND

Given the large number of workers in the construction industry, it is important to derive accurate and valid estimates of cancer risk, and in particular lung cancer risk. In most previous studies, risks among construction workers were compared with general populations including blue and white collar workers. The main objectives of this study were to assess whether construction workers experience excess lung cancer risk, and whether exposure to selected construction industry exposures carries excess risks. We wished to address these objectives within the sub-population of blue collar workers.

METHODS

Two case-control studies were conducted in Montreal. Combined, they included 1593 lung cancer cases and 1427 controls, of whom 1304 cases and 1081 controls had been blue collar workers. Detailed lifetime job histories were obtained and translated by experts into histories of exposure to chemical agents. The two key analyses were to estimate odds ratio (OR) estimates of lung cancer risk: a) for all blue-collar construction workers compared with other blue-collar workers, and b) for construction workers exposed to each of 20 exposure agents found in the construction industry compared with construction workers unexposed to those agents. All analyses were conducted using unconditional logistic regression adjusted for socio-demographic factors and smoking history.

RESULTS

The OR for all construction workers combined was 1.11 (95 % CI: 0.90-1.38), based on 381 blue collar construction workers. Analyses of specific exposures were hampered by small numbers and imprecise estimates. While none of 20 occupational agents examined was significantly associated with lung cancer, the following agents manifested non-significantly elevated ORs: asbestos, silica, Portland cement, soil dust, calcium oxide and calcium sulfate.

CONCLUSIONS

Compared with other blue collar workers, there was only a slight increased risk of lung cancer for subjects who ever held an occupation in the construction industry. The analyses of agents within the construction industry produced imprecise estimates of risk, but nevertheless pointed to some plausible associations. Excess risks for asbestos and silica were in line with previous knowledge. The possible excess risks with the other inorganic dusts require further corroboration.

Perspectives in Biological Monitoring of Inhaled Nanosized Particles

Given the results of experimental studies, occupational or environmental exposures to manufactured nanoparticles or to unintentionally produced ultrafine particles may result in health effects or diseases in humans. In this review, we synthesize published data of experimental studies on the distribution of inhaled nanoparticles and the first case reports to discuss the potential usefulness of their biological monitoring for clinical purposes. Toxicokinetic studies suggest that nanoparticles may be absorbed predominantly by respiratory and oral routes with possible systemic translocation, leading to accumulation in the peripheral organs or excretion in feces or urine. Some methods used in these studies may be applied successfully in retrospective evaluation of exposure or in follow-up of occupational exposure in the workplace. Biological monitoring of nanoparticles should be based on imaging methods that are essential to confirm their presence and to characterize them in tissue associated with analytical quantitative methods. The first case reports reviewed emphasize the urgent need for the development of standardized procedures for the preparation and analysis of biological samples with a view to characterizing and quantifying nanoparticles.

Co-exposure to refractory ceramic fibres and asbestos and risk of pleural mesothelioma

The aim of this study was to investigate the hypothesis of an increased risk of pleural mesothelioma due to co-exposure to asbestos and refractory ceramic fibres (RCF) compared to asbestos exposure alone. Males were selected from a French case-control study conducted in 1987-1993 and from the French National Mesothelioma Surveillance Program in 1998-2006. Two population controls were frequency matched to each case by year of birth. Complete job histories were collected and occupational asbestos and RCF exposures were assessed using job exposure matrices. The dose-response relationships for asbestos exposure were estimated from an unconditional logistic regression model in subjects exposed to asbestos only (group 1) and subjects exposed to both asbestos and RCF (group 2). A total of 988 cases and 1125 controls ever-exposed to asbestos were included. A dose-response relationship was observed in both groups but it was stronger in group 2. In comparison with subjects exposed at the minimum value of the cumulative index of exposure, the odds ratio was 2.6 (95% CI 1.9-3.4) for subjects exposed to 75 fibres · mL(-1) · year(-1) in group 1 increasing to 12.4 (95% CI 4.6-33.7) in group 2. Our results suggest that the pleural carcinogenic effect of occupational asbestos exposure may be modified by additional exposure to RCF.

Occupational and non-occupational attributable risk of asbestos exposure for malignant pleural mesothelioma

OBJECTIVES

To estimate the proportion of pleural mesothelioma cases that can be attributed to asbestos exposure in France including non-occupational exposure.

METHODS

A population-based case-control study including 437 incident cases and 874 controls was conducted from 1998 to 2002. Occupational and non-occupational asbestos exposure was assessed retrospectively by two expert hygienists. ORs of pleural mesothelioma for asbestos-exposed subjects compared to non-exposed subjects, and population-attributable risk (ARp) of asbestos exposure were estimated using a conditional logistic regression.

RESULTS

A clear dose-response relationship was observed between occupational asbestos exposure and pleural mesothelioma (OR=4.0 (99% CI 1.9 to 8.3) for men exposed at less than 0.1 f/mL-year vs. 67.0 (99% CI 25.6 to 175.1) for men exposed at more than 10 f/mL-year). The occupational asbestos ARp was 83.1% (99% CI 74.5% to 91.7%) for men and 41.7% (99% CI 25.3% to 58.0%) for women. A higher risk of pleural mesothelioma was observed in subjects non-occupationally exposed to asbestos compared to those never exposed. The non-occupational asbestos ARp for these subjects was 20.0% (99% CI -33.5% to 73.5%) in men and 38.7% (99% CI 8.4% to 69.0%) in women. When considering all kinds of asbestos exposure, ARp was 87.3% (99% CI 78.9% to 95.7%) for men and 64.8% (99% CI 45.4% to 84.3%) for women.

CONCLUSIONS

Our study suggests that the overall ARp in women is largely driven by non-occupational asbestos exposure arguing for the strong impact of such exposure in pleural mesothelioma occurrence. Considering the difficulty in assessing domestic or environmental asbestos exposure, this could explain the observed difference in ARp between men and women.

Characterization of a French series of female cases of mesothelioma

BACKGROUND

More than 80% of mesothelioma cases in men are attributable to occupational asbestos exposure compared to only 40% in women. The objective of the study was to characterize a series of female pleural mesotheliomas according to known and suspected risk factors.

METHODS

From the exhaustive recording of 318 female mesothelioma cases in the French National Mesothelioma Surveillance Program between 1998 and 2009, multiple correspondence analysis and hybrid clustering were performed to characterize these cases according to expert assessed occupational and non-occupational exposure to asbestos and man-made vitreous fibers, X-ray exposure, and history of cancer and non-malignant respiratory diseases.

RESULTS

Four clusters were identified: (1) occupational exposure to asbestos and man-made vitreous fibers (7.9% of subjects); (2) radiation exposure during radiotherapy (12.9%); (3) increased asbestos exposure (19.8%); and (4) "non-exposure" characteristics (59.4%).

CONCLUSION

These results will allow hypotheses to be generated about associations between mesothelioma and non-occupational asbestos exposure, X-ray exposure and history of respiratory disease.

On the proportional hazards model for occupational and environmental case-control analyses

Background

Case-control studies are generally designed to investigate the effect of exposures on the risk of a disease. Detailed information on past exposures is collected at the time of study. However, only the cumulated value of the exposure at the index date is usually used in logistic regression. A weighted Cox (WC) model has been proposed to estimate the effects of time-dependent exposures. The weights depend on the age conditional probabilities to develop the disease in the source population. While the WC model provided more accurate estimates of the effect of time-dependent covariates than standard logistic regression, the robust sandwich variance estimates were lower than the empirical variance, resulting in a low coverage probability of confidence intervals. The objectives of the present study were to investigate through simulations a new variance estimator and to compare the estimates from the WC model and standard logistic regression for estimating the effects of correlated temporal aspects of exposure with detailed information on exposure history.

Method

We proposed a new variance estimator using a superpopulation approach, and compared its accuracy to the robust sandwich variance estimator. The full exposure histories of source populations were generated and case-control studies were simulated within each source population. Different models with selected time-dependent aspects of exposure such as intensity, duration, and time since cessation were considered. The performances of the WC model using the two variance estimators were compared to standard logistic regression. The results of the different models were finally compared for estimating the effects of correlated aspects of occupational exposure to asbestos on the risk of mesothelioma, using population-based case-control data.

Results

The superpopulation variance estimator provided better estimates than the robust sandwich variance estimator and the WC model provided accurate estimates of the effects of correlated aspects of temporal patterns of exposure.

Conclusion

The WC model with the superpopulation variance estimator provides an alternative analytical approach for estimating the effects of time-varying exposures with detailed history exposure information in case-control studies, especially if many subjects have time-varying exposure intensity over lifetime, and if only one control is available for each case.

Glycogen depletion patterns in myofibres of cattle during stress

The response of the three major types of fibre in beef M. longissimus dorsi during stress and recovery was examined with respect to cellular glycogen content. Two different forms of stress were induced in Friesian bulls, by mixing with strangers for a 5h period or by subcutaneous injections of adrenaline. Muscle biopsy samples were taken during stress and recovery for biochemical and histochemical analysis of glycogen content. Muscle glycogen concentration fell to 45% of the resting value during mixing stress and to 37% of the resting value after adrenaline treatment. Slow-twitch and fast-twitch fibre types responded differently to stress, and the differences were reversed in the two forms of stress studied. Mixing stress caused a greater loss of glycogen from the two fast fibre types than from the slow type while adrenaline caused a much greater loss of glycogen from the slow fibres than from the two fast fibre types. The results demonstrate that glycogen is selectively depleted in muscle fibres in response to stress and that the pattern of depletion is different in adrenaline versus mixing stress.