scholarly journals A Quantitative Retrospective Exposure Assessment for Former Chrysotile Asbestos Miners and Millers from Baie Verte, NL, Canada

2020 ◽  
Author(s):  
Tina Giles Murphy ◽  
Stephen Bornstein ◽  
John Oudyk ◽  
Paul A Demers
Keyword(s):  
Exposure Assessment ◽  
Asbestos Exposure ◽  
Epidemiologic Study ◽  
Geometric Standard Deviation ◽  
Chrysotile Asbestos ◽  
Adequate Quality ◽  
Compensation Claims ◽  
Job Title ◽  
Log Normal ◽  
Work Histories

Abstract Despite numerous studies of asbestos workers in the epidemiologic literature, there are very few cohort studies of chrysotile asbestos miners/millers that include high-quality retrospective exposure assessments. As part of the creation of the Baie Verte Miners’ Registry in 2008, a two-dimensional job exposure matrix (JEM) was developed for estimating asbestos exposures for former chrysotile asbestos miners/millers. Industrial hygiene data collected between 1963 and 1994 were analysed to assess validity for use in a retrospective exposure assessment and epidemiologic study. Registered former employees were divided into 52 exposure groups (EGs) based on job title and department and mean asbestos concentrations were calculated for each EG. The resulting exposure estimates were linked to individual registrants’ work histories allowing for the calculation of cumulative asbestos exposure for each registrant. The distribution of exposure for most EGs (82.6%) could be described as fitting a log-normal distribution, although variability within some EGs (55%) exceeded a geometric standard deviation (GSD) of 2.5. Overall, the data used to create EGs in the development of the JEM were deemed to be of adequate quality for estimating cumulative asbestos exposures for the former employees of the Baie Verte asbestos mine/mill. The variability between workers in the same job was often high and is an important factor to be considered when using estimates of cumulative asbestos exposure to adjudicate compensation claims. The exposures experienced in this cohort were comparable to those of other chrysotile asbestos miners/millers cohorts, specifically Italian and Québec cohorts.

Malignant Mesothelioma Among Employees of a Connecticut Factory That Manufactured Friction Materials Using Chrysotile Asbestos: An Update

2019 ◽  
Author(s):  
Murray M Finkelstein ◽  
Christopher Meisenkothen
Keyword(s):  
Health Effects ◽  
Malignant Mesothelioma ◽  
Fiber Type ◽  
Epidemiologic Study ◽  
Original Description ◽  
Risk Assessments ◽  
Asbestos Fiber ◽  
Chrysotile Asbestos ◽  
Friction Materials ◽  
Work Histories

Abstract There is an ongoing argument about the potency of chrysotile asbestos to cause malignant mesothelioma. Authors of chrysotile risk assessments have relied upon the results of an epidemiologic study, published in 1984, to state that there were no mesotheliomas found among workers at a Connecticut friction products plant. McDonald reported the first two cases in 1986. In 2010, we reported the work histories and pathologic reports of five individuals from the Connecticut plant who were diagnosed with mesothelioma. Despite this, a review of the health effects of chrysotile published in 2018 continued to state that there were no cases of mesothelioma from this plant. We report here two new cases that were diagnosed after the publication of our previous report, bringing the current total to nine cases. We also discuss the results of previously unpublished air sampling data from the plant. Chrysotile, mainly from Canada, was the only asbestos fiber type used until 1957 when some anthophyllite was added in making paper discs and bands. Beyond this original description of the anthophyllite usage from McDonald, there is a dearth of information about the amount of anthophyllite used in the plant, the frequency of its use, and the specific departments where it was used. For over 30 years in the published literature, this factory has alternatively been described as a ‘chrysotile’ or ‘predominantly chrysotile’ factory. While it is clear that some anthophyllite was used in the factory (in addition to 400 pounds of crocidolite in the laboratory), given the volume, frequency, and processes using chrysotile, it still seems satisfactory to describe this cohort as a predominantly, but not exclusively, chrysotile-exposed cohort.

Chrysotile asbestos exposure in the manufacturing of thermal insulating boards

2009 ◽  
Vol 167 (1-4) ◽  
pp. 559-564 ◽  
Author(s):  
L. J. Bhagia ◽  
J. B. Vyas ◽  
M. I. Shaikh ◽  
S. L. Dodia
Keyword(s):  
Asbestos Exposure ◽  
Chrysotile Asbestos ◽  
Thermal Insulating

scholarly journals O8A.4 Asbestos exposure and prostate cancer, really?

2019 ◽  
Vol 76 (Suppl 1) ◽  
pp. A71.1-A71
Author(s):  
Marie-Elise Parent ◽  
M Hugues Richard
Keyword(s):  
Prostate Cancer ◽  
Cancer Risk ◽  
Asbestos Exposure ◽  
Large Population ◽  
Prostate Cancer Risk ◽  
Cumulative Exposure ◽  
Population Exposure ◽  
Specific Information ◽  
Chrysotile Asbestos ◽  
Increased Risk

BackgroundGeneral population exposure to asbestos from residential insulation and from environmental sources during childhood have recently been associated with prostate cancer. While asbestos fibers can be found in the prostate of workplace-exposed men at autopsy, few occupational studies have reported on asbestos exposure and prostate cancer incidence. We examined the association between lifetime occupational exposure to chrysotile asbestos and prostate cancer risk in a large population-based case-control study.MethodsCases were 1933 men with histologically-confirmed incident prostate cancer, aged ≤75 years, diagnosed in 2005–2009 in Montreal. Concurrently, 1994 population controls from the same residential area and age distribution were randomly selected from electoral lists. In-person interviews elicited detailed socio-demographics, lifestyle and work histories. Industrial hygienists used job-specific information to provide semi-quantitative evaluations of intensity and frequency of exposure to 345 chemical agents, including asbestos, and a measure of confidence in the evaluation. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for prostate cancer risk associated with exposure to chrysotile asbestos.ResultsAfter restriction to probable and definite exposure, and application of a 5 year lag, 12.5% of cases and 11.8% of controls were ever exposed to asbestos (OR=1.1, 95% CI 0.9–1.3). For duration of exposure, there was no increase in risk of overall prostate cancer in the lower tertiles of exposure but risk was elevated in the upper tertile (OR=1.6, 95% CI 1.2–2.2). Similarly, for cumulative exposure, risk was elevated in the upper tertile only (OR=1.5, 95% CI 1.1–2.1). Analyses considering tumor grades also showed a higher risk in the upper tertile of cumulative exposure for non-aggressive (OR=1.5, 95% CI 1.1–2.2) and especially aggressive (OR=1.9, 95% CI 1.2–3.0) cancers.ConclusionOur findings are consistent with an increased risk of prostate cancer with prolonged and high cumulative exposure to chrysotile asbestos, and particularly for the aggressive form of the disease.

scholarly journals Characterizing Short-Term Jobs in a Population-Based Study

2019 ◽  
Vol 63 (6) ◽  
pp. 701-705 ◽  
Author(s):  
Marie-Élise Parent ◽  
Hugues Richard ◽  
Jean-François Sauvé
Keyword(s):  
Exposure Assessment ◽  
Population Based ◽  
Short Term ◽  
Population Based Study ◽  
Outdoor Work ◽  
Disease Aetiology ◽  
Lifetime Exposure ◽  
Poor Ventilation ◽  
Work Histories ◽  
Control Study

Abstract Background Work histories generally cover all jobs held for ≥1 year. However, it may be time and cost prohibitive to conduct a detailed exposure assessment for each such job. While disregarding short-term jobs can reduce the assessment burden, this can be problematic if those jobs contribute important exposure information towards understanding disease aetiology. Objective To characterize short-term jobs, defined as lasting more than 1 year, but less than 2 years, in a population-based study conducted in Montreal, Canada. Methods In 2005–2012, we collected work histories for some 4000 participants in a case-control study of prostate cancer. Overall, subjects had held 19 462 paid jobs lasting ≥1 year, including 3655 short-term jobs. Using information from interviews and from the Canadian Classification and Dictionary of Occupations, we characterized short-term jobs and compared them to jobs held ≥2 years. Results Short-term jobs represented <4% of subjects’ work years on average. Forty-five per cent of subjects had at least one short-term job; of these, 49% had one, 24% had two, and 27% had at least three. Half of all short-term jobs had been held before the age of 24. Short-term jobs entailed more often exposure to fumes, odours, dust, and/or poor ventilation than longer jobs (17 versus 13%), as well as outdoor work (10 versus 5%) and heavy physical activity (16 versus 12%). Conclusions Short-term jobs occurred often in early careers and more frequently entailed potentially hazardous exposures than longer-held jobs. However, as they represented a small proportion of work years, excluding them should have a marginal impact on lifetime exposure assessment.

Asbestos fiber identification in liver from cholangiocarcinoma patients living in an asbestos polluted area: a preliminary study

2019 ◽  
Vol 105 (5) ◽  
pp. 404-410 ◽  
Author(s):  
Federica Grosso ◽  
Alessandro Croce ◽  
Roberta Libener ◽  
Narciso Mariani ◽  
Massimo Pastormerlo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Asbestos Exposure ◽  
Optical Microscope ◽  
Variable Pressure ◽  
Chrysotile Asbestos ◽  
Neoplastic Tissue ◽  
Asbestos Fibers ◽  
Preliminary Study ◽  
Scanning Electron

Purpose: To assess whether asbestos fibers may be observed in liver tissue of patients with cholangiocarcinoma (CC) with environmental or working asbestos exposure. Methods: Detection of fibers was performed directly on histologic sections of liver from 7 patients with CC using optical microscope and variable pressure scanning electron microscopy equipped with energy-dispersive spectroscopy (VP-SEM/EDS). All patients were from Casale Monferrato, Italy, a highly asbestos-polluted town. Due to ethical constraints, observers were blinded to patients’ clinical features. Results: Fibers/bundles of fibers of chrysotile were detected in 5 out of 7 patients (71%). The boundary between healthy and neoplastic tissue or the fibrocollagen tissue produced by the neoplasia were identified as areas of fiber incorporation. Conclusions: This study is the first report about the detection of chrysotile asbestos fibers in the liver of patients with CC. Further studies on larger cohorts are needed to corroborate our preliminary findings.

Electricians’ chrysotile asbestos exposure from electrical products and risks of mesothelioma and lung cancer

2014 ◽  
Vol 68 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Julie E. Goodman ◽  
Michael K. Peterson ◽  
Lisa A. Bailey ◽  
Laura E. Kerper ◽  
David G. Dodge
Keyword(s):  
Lung Cancer ◽  
Asbestos Exposure ◽  
Chrysotile Asbestos

The effects of changing levels of arousal on the spontaneous activity of cortical neurones II. Relaxation and alarm

1976 ◽  
Vol 194 (1115) ◽  
pp. 239-251 ◽  
Keyword(s):  
Spontaneous Activity ◽  
Temporal Pattern ◽  
Discharge Rate ◽  
Geometric Standard Deviation ◽  
Sudden Increase ◽  
Lateral Cortex ◽  
Infrared Telescope ◽  
Modal Interval ◽  
Log Normal ◽  
Two Parameters

In a previous paper it has been shown that interval distributions derived from the activity of single cortical neurones can be described by log-normal curves. A cell’s temporal pattern of discharge can therefore be defined by the values of two parameters – a modal interval, and a geometric standard deviation (g. s. d.). It has also been shown that the values of both parameters change when an animal falls asleep. The modal interval becomes shorter, and the g. s. d. usually becomes larger. This paper deals with the effects of changes in arousal of animals which are awake; and, in particular, with the effects of the transition from relaxation to alarm. Single unit recordings have been made from neurones in the post-lateral and supra-sylvian gyri of unrestrained cats. In order to eliminate the direct effects of eye-movements, the experiments were carried out in complete darkness, and the animal was observed through an infrared telescope. Alarm was produced by the hiss of compressed air. An animal was said to be alarmed when he stood up abruptly and turned towards the source of the noise. Alarm produced a marked fall in the discharge frequency of those cells in post-lateral cortex which initially showed a low ( < 2 action potentials per second) rate of spontaneous activity. The discharge rate of the remaining neurones (whether in suprasylvian or post-lateral cortex) was unaffected by the sudden increase in arousal. But the temporal pattern of discharge of every cell was altered. The modal interval became longer when the animal was alarmed, and the g. s. d. usually became smaller. Such changes could have been predicted from a knowledge of the neural concomitants of the transition from sleep to wakefulness. These results suggest that the activity of all cortical neurones is affected by the level of arousal of the animal, and that this modulation takes the form of a continuum of possible modal intervals, and possible g.s.ds.

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