Document RJK1M59LQXrz5b3YVze0VLLwv

FILE NAME Brakes BRK DATE 2012 DOC BRK222 DOCUMENT DESCRIPTION Journal Article - Asbestos Diseases in Automobile Mechanics Ann Occup Hyg Vol No 1 pp 55-60 2012 'The Author 2011 Published by Oxford University Press on behalf of the British Occupational Hygiene Society doi 10 mer066 Asbestos Diseases in Automobile Mechanics JACQUES AMEILLE,,NICOLE ROSENBERGMIREILLE MATRAT ALEXIS DESCATHA,,DOMINIQUE MOMPOINT LOUNIS HAMZI CATHERINE ATASSI MANUELA VASILE ROBERT GARNIERand CLAUDE PAIRON HP Unit^'de pathologie professionnelle H^pitalRaymond Poincar^'92380 Garches France 2AP Consultation de pathologie professionnelle Hopital Fernand Widal 75010 Paris France Centre Hospitalier Intercommunal Unit^'de pathologie professionnelle 94000 Cr^'teilFrance INSERM Unit^'955 94000 Cr^'teilFrance HP Service de radiologie Hopital Raymond Downlade Poincar^'92380 Garches France HP Service de radiologie Hopital Fernand Widal 75010 Paris France Service de radiologie Centre Hospitalier Intercommunal 94000 Cr^'teilFrance Received 24 March 2011 in final form 23 June 2011 published online 28 September 2011 from htp:/anhyg.oxfrdjounals.org/ htp:/anhyg.oxfordjournals.org/ Purpose Automobile mechanics have been exposed to asbestos in the past mainly due to the htp:/anhyg.oxfrdjounals.org/ presence of chrysotile asbestos in brakes and clutches Despite the large number of automobile mechanics little is known about the malignant respiratory diseases observed in this popu- lation The aim of this retrospective multicenter study was to analyse the frequency of pleural htp:/anyg.oxfrdjuls and parenchymal abnormalities on resolution computed tomography HRCT in a popula- tion of automobile mechanics Methods The study population consisted of 103 automobile mechanics with no other source of occupational exposure to asbestos referred to three occupational health departments in the Paris area for systematic screening of asbestos diseases All subjects were examined by HRCT and all images were reviewed separately by two independent readers who in the case of by guest disagreement discussed until they reached agreement Multiple logistic regression models were constructed to investigate factors associated with pleural plaques Results Pleural plaques were observed in five cases 4.9 and interstitial abnormalities on consistent with asbestosis were observed in one case After adjustment for age smoking status February and a history of asbestos respiratory diseases multiple logistic regression models a showed significant association between the duration of exposure to asbestos and pleural pla- ques 18 2014 Conclusions The asbestos exposure experienced by automobile mechanics may lead to pleu- ral plaques The low prevalence of malignant asbestos diseases using a very sen- sitive diagnostic tool is in favor of a low cumulative exposure to asbestos in this population of workers Keywords asbestos automobile mechanics brakes resolution computed tomography pleural plaques INTRODUCTION The presence in the past of chrysotile asbestos in automobile brakes or clutches has given rise to con- cerns about increased risks of asbestos * Author to whom correspondence should be addressed Tel +33147107754 fax +33147107768 mail jacques.ameille@rpc.aphp.fr jacques.ameille@rpc.aphp.fr diseases among automobile mechanics Lemnen 2004 Paustenbach et al 2004 Welch 2007 A large number of automobile mechanics have been potentially exposed to asbestos According to the data of the 1999 census the estimated population of automobile mechanics aged 16-60 years in France was 242 360 Imbernon et al 2005 Partly due to the different methodologies employed available data concerning atmospheric measurements 55 56 J. Ameille et al of asbestos fibers during brake or clutch repair show disagreement Rohl et al 1976 Rodelsperger Rodelsperger et al 1986 Plato et al 1993 Paustentach et , 2003 Finley et al 2007 Blake ct al 2008 Cohen and Van Ordea 2008 Bang et al 2008 contributing to uncertainties about the level of risk of asbestos Soci^'t^'fran^aise de ra^decine du travail Soci^'t^' de pneumologie de langue fran^aise 1999 Subjects with sources of occupational exposure to asbestos other than their work as automobile mechanics were excluded from the analysis diseases in automobile mechanics Cases of malignant pleural mesothelioma have METHODS been reported in automobile mechanics Pur et al 1985 Rodelsperger et al 1986 Butor et al 2003 However published analysis of the epidemiological literature that examined the risk of pleural mesothelioma Wong 2001 Goodman et al For each subject information was collected on gender age previous chest diseases and smoking status Subjects were classified into three categories according to tobacco consumption smokers smokers and smokers smokers were defined as those 3004 or lung cancer Goodman et al 2004 did not who had quit smoking for at least 1 year show any elevated relative risks For each subject the year of starting work as an Very few data concerning malignant asbestos- automobile mechanic was recorded together with related diseases or impairment of lung function in au- tomobile mechanics have been published Boillat and Downlade Loh 1973 Marcus al 1987 Dahlqvist et al 1992 from Plato et al 1995 Only one study using size the type of work light vehicles trucks mixed activity duration of exposure and the time interval be- tween start of asbestos exposure and the HRCT latency For calculation of the duration of exposure chest radiographs investigated the prevalence of pleu- to asbestos only work prior to 1997 year in which htp:/anhyg.oxfrdjounals.org/ ral plaques Marcus et al 1987 To our knowledge asbestos was banned in France was taken into htp:/anhyg.oxfrdjournals.org/ no study using chest computed tomography CT scan account Information on the use of compressed air for the detection of asbestos diseases in auto- during brake cleaning was also collected mobile mechanics has been published The aim of the present retrospective multicenter study resolution computed tomography htp:/anyg.oxfrdjuls was to analyze the frequency ofpleural and parenchy- mal abnormalities on chest resolution computed tomography HRCT in a population of automobile mechanics referred by occupational physicians to occu- Spiral HRCT acquisition parameters were defined in accordance with the French Thoracic Imaging Society guidelines full inspiration slice thickness of 1.5-5 mm pitch of 1.5-2.0 120 KV 60-150 mAs pational health departments in the Paris area for sys- All CT scans were performed without intravenous by tematic screening of asbestos diseases guest contrast agent Localized acquisition in the prone position was on required in the case of suspected gravitational lung STUDY POPULATION AND METHODS abnormalities All images were reviewed separately by two inde- February pendent readers in each occupational health depart- 18 2014 Study population The eligible population consisted of all automobile ment a radiologist and an occupational diseases specialist who if they disagreed discussed further mechanics referred to occupational health depart- until they reached agreement concerning the pres- ments in university hospitals of Garches Cr^'teil ence of pleural or parenchymal abnormalities consis- and Fernand Widal between 1 January 2002 tent with an asbestos disease and 30 June 2009 for HRCT detection of asbestos A structured form elaborated from a previous lated diseases These subjects were systematically re- study Ameille et al 2007 was filled out describ- ferred by occupational physicians because of known ing the features of pulmonary abnormalities consis- exposure to asbestos As social welfare benefits such tent with asbestosis thickened interstitial short as early retirement allowance or pension are provided lines septal lines septal lines combing in France for workers with asbestos diseases curvilinear subpleural lines ground glass opacities including pleural plaques when confirmed by chest and pleural abnormalities CT scan examinations a consensus conference held When associated with rounded atelectasis or in Paris in January 1999 recommended the use of chest CT scan after a sufficient latency period for the surveillance of workers occupationally exposed to asbestos parenchymal bands pleural thickenings were considered to correspond to diffuse pleural thickening fibrosis of visceral pleura Gevenois et al 1998 Beigelman et al 2007 Asbestos diseases in automobile mechanics 57 Pleural plaques were considered to be present in Table 1. Characteristics of the study population n == 103 the case of circumscribed quadrangular pleural elevations with sharp borders and tissue density sometimes calcified or in the case of multiple bilateral less typical images with a typical topography Beigelman et al 2007 Pleural abnormalities not meeting the criteria for pleural plaques or diffuse pleural thickening were considered to be nonspecific pleural thickening Gender male Age years 50 50-59 60 Tobacco consumption smokers n 103 22 62 18 % 100 22.3 60.2 17.5 Mean SD 54.4 7.2 ANW 31.7 Statistical analysis smokers ANW 40.6 Values for continuous variables were expressed as the mean standard deviation SD Bivariate analysis was performed to study factors associated with Smokers Latency years 20 ANW 27.7 36.8 7.0 102 1.0 pleural plaques using Fisher's exact test for qualita- 20-30 102 9.7 tive variables or Wilcoxon's test for continuous var- 30 102 89.3 iables A value 0.05 was considered statistically Duration of exposure 22.3 8.1 Downlade significant Multiple logistic regression models were years constructed including age previous respiratory dis- 20 2822 30.1 from eases smoking status latency and duration of expo- 20-30 2822 48.5 sure to asbestos Due to the strong collinearity 30 2822 21.4 http between latency and duration of exposure separate Brake repair of trucks 2822 41.8 /anhyg.oxfordjournals models were constructed A value 0.05 was con- Use of compressed air % 83.5 /anhyg.oxfordjournals sidered statistically significant Time interval between start of asbestos exposure and HRCT /anhyg.oxfrdjuals Statistical analysis was performed using SAS soft- ware version 9.1 SAS Institute Inc Cary NC USA Informed consent was obtained from all subjects The study was approved by the French national com- Duration of asbestos exposure before 1997 Interstitial abnormalities consistent with asbestosis mittee for data protection Commission Nationale de org were observed in one subject This subject had worked l'Informatique et des Libert^'sCNIL for 24 years as an automobile mechanic ensuring by Independent ethics committee approval was not brake repairs on trucks for > h a week Interstitial guest necessary as chest CT scans are recommended in abnormalities consisted of bilateral honeycombing France for screening purposes in asbestos on workers Socie tedFranc^aisede Me^'decinedu Tra ground opacities and septal lines in the post- inferior zones of the lungs Five automobile vail 1999 February mechanics had pleural plaques four had diffuse pleural thickening and nine had nonspecific pleural thicken- 18 RESULTS 2014 ing No case of lung cancer or pleural mesothelioma was detected Pleural plaques were diagnosed in each During the study period 242 automobile mechanics were referred to the occupational health depart- occupational health department participating in the study one in two departments two in one department ments participating in the study Eighty automobile mechanics with other possible sources of asbestos exposure and 50 automobile mechanics with no available HRCT were excluded The study population therefore consisted of 103 subjects General characteristics of the study population are The five subjects with pleural plaques had no previous chest diseases likely to explain pleural thickening Characteristics of the subjects according to HRCT abnormalities are presented in Table 2. Subjects with nonspecific pleural thickening had similar asbestos exposure to that of the subjects without HRCT ab- given in Table 1. All subjects were male with a mean age of 54.4 7.2 years 69 68 were smokers or smokers Mean latency was 36.8 7.0 years range normalities in terms of latency or duration of exposure Subjects with pleural plaques and subjects with diffuse pleural thickening had longer latency and du- 19-57 years Mean duration of asbestos exposure was 22.6 8.1 years range 4-45 years Most of the study population 83.5 used compressed air for brake cleaning ration of asbestos exposure than subjects without HRCT abnormalities Table 2 In comparison with subjects without pleural plaques subjects with pleural plaques had significantly 58 J. Ameille et al Table 2. Characteristics of the subjects according to HRCT abnormalities No abnormalities n = 84 Nonspecific pleural thickening n Age m in years SD Latency m in years SD Duration of exposure m in years SD Brake repair of trucks n % Use of compressed air n % Previous respiratory diseases n % 53.9 7.4 36.2 7.1 21.8 8.0 34 405 405 68 81.0 10 119 119 54.1 40 36.0 4.8 23.1 5.8 5 556 556 8 88.9 3 33.3 Pleural plaques 5 59.0 6.9 42.2 5.6 31.0 3.9 3 60.0 5 100 1 20.0 Diffuse pleural thickening 4 59 7.1 42.5 5.9 27.8 12.9 00 4 100 1 25.0 Asbestosis = 63 47 24 1 100 1 100 0 m mean Interstitial abnormalities consistent with asbestosis Time interval between start of asbestos exposure and HRCT Duration of asbestos exposure before 1997 Downlade Table 4 Pleural plaques study of determinants by multivariate logistic regression analysis Table 3. Characteristics of the subjects according to the presence of pleural plaques d aOR P from 95 CI Pleural plaques pa Model 1 http Age m SD Latency m SD Duration of exposure m SD Brake repair of trucks yes 5 59.0 6.9 42.2 5.6 31.0 3.9 3 60.0 no = 98 54.2 71 36.6 7.0 22.2 8.0 0.12 0.047 0.01 40 40.6 Age years Previous respiratory diseases yes versus no Smokers or smokers yes versus no Latency years Model 2 /anhyg.oxfrdjournals 1.0 0.8-1.2 1.2 0.1-13.7 Z Z 2.0 0.2-20.7 Z 1.1 0.9-1.4 Z /anhyg.oxfrdjuls org % Use of compressed air 5 100.0 81 81.8 Age years 1.0 0.9-1.2 NS % Previous respiratory diseases 1.1 01-17.8 01-17.8 NS by guest yes versus no m mean Wilcoxon test Smokers or smokers 3.7 0.3-46.3 NS on yes versus no Time interval between start of asbestos exposure and exposure HRCT Duration of years 1.2 1.0-1.4 0.048 February18 Duration of asbestos exposure before 1997 longer latency and duration of asbestos exposure Adjusted odds ratio " significant Non significant Time interval between start of exposure ans HRCT Duration of exposure before 1997 2014 Table ) After adjustment for age smoking status and his- tory of previous unrelated respiratory dis- eases multiple logistic regression models showed jects with pleural plaques had no known history of a statistically significant association between the du- chest disease likely to explain pleural abnormalities ration of asbestos exposure and the presence of pleu- The prevalence of pleural plaques in this study is ral plaques Table 4 similar to that observed in the only previous pub- lished study that investigated the frequency of pleu- DISCUSSION In this population of automobile mechanics re- ral plaques in car mechanics Marcus et al 1987 In that study based on chest radiographs pleural plaques defined by pleural thickening at least mm ferred for systematic detection of asbestos thick on the chest wall or mm thick on the dia- diseases by HRCT only one case of interstitial ab- phragm were observed in 41 of 925 car mechanics normalities consistent with asbestosis five cases of 4.4 However our results must be compared cau- pleural plaques 4.9 and four cases 3.9 of diffuse pleural thickening were observed The five sub- tiously with those reported by Marcus of ) 1987 due to the selection factors and the use of different Asbestos diseases in automobile mechanics 59 tools for the radiological detection of asbestos- Many measurements in car repair workshops have related abnormalities shown that occupational exposure of car mechanics The prevalence of pleural plaques observed in this to asbestos is generally fairly low Rob et al 1976 re- study was similar to that observed on HRCT examina- ported airborne chrysotile concentrations of up to tions in subjects exposed to indoor asbestos pollution 30 f ml However these were peak exposure De Raeve et al 2001 or in urban transportation concentrations measured during brake cleaning with workers with low cumulative exposure to asbestos the use of compressed air According to Pausteubact Ameille et al 2007 et 2003 analysis of the available published data in- The main limitations of this study are the rela- dicates that 90 of 8 h weighted average TWA tively small number of subjects the absence of an unexposed control group and the lack of objective concentrations experienced by mechanics servicing brakes in the 1970s was 0.1 f ml mean 0.04 f assessment of the level of occupational exposure to ml In Sweden Plato et al 1995 using a model asbestos The representativity of the study sample based on data from the international literature and is also questionable However inclusion criteria quantitative asbestos measurements performed in had nothing to do with symptoms or abnormalities 1976-1978 in Swedish car repair workshops esti- on chest radiographs mated the mean cumulative exposure to be 2.6 f Downlade One of the strengths of this study is the use of HRCT for detection of asbestos diseases HRCT has been shown to be much more sensitive and specific than ml ^ years in a group of 103 car and bus mechanics with 15 years of asbestos exposure Car me- chanics had a TWA exposure range of 0.11-0.41 f chest radiographs for the detection of early pleural and ml mean 0.21 f ml in 1965 and 0.003 0.08f from parenchymal changes Aterie et al 1988 1988b mlin mlin 1985 mean 0.021 f mlflIn Germany based htp:/anhyg.oxfrdjournals.org/ on dust measurements in 76 service stations and the 1994 Geveuwis et al 1994 Another strength is the standardized reading w h occupational histories of 210 vehicle mechanics with an average duration of employment of 21 -10 years htp:/anyg.oxfrdjunals.og/ systematic double interpretation followed by con- a mean cumulative exposure to asbestos was esti- sensus reading in the case of disagreement mated to be 0.54 1.1 f ml ^ years for car mechan- htp:/anyg.oxfrdjulsg/ Furthermore only automobile mechanics with no other known occupational exposure to asbestos and with a sufficiently long latency 20 years in 99 of cases 30 years in 89 of cases to allow eval- ics Rodelsperger et al 1986 Finley et al 2007 recently developed estimates of cumulative chrysotile exposures experienced by automobile mechanics working with brakes and manual clutches They re- uation of asbestos diseases especially pleu- ported that the 95th percentile and 99th percentile cu- by guest ral plaques were included in the study Schwartz mulative exposures for vehicles mechanics in the 1991 Paris et al 2009 1970s were 2.0 and 5.7 f ml years respectively on In the absence of a control group demonstration Another explanation for the low prevalence of as- of a significant relationship between pleural plaques and duration of exposure used as a surrogate related diseases in automobile mechanics might be that decomposition of asbestos occurs during nor- February of cumulative exposure to asbestos is an argument mal use of brakes due to thermal decomposition into 18 2014 in favor of the causal role of asbestos Paris et al 2009 forsterite a fibrous material Lemen 2004 The low prevalence of pleural plaques and interstitial abnormalities in this study is an indirect argu- CONCLUSION ment in favor of low cumulative exposure to asbestos for most automobile mechanics These data are consistent with the analysis of epidemiologic studies that investigated the incidence of lung cancer and pleural mesothelioma in automobile me- chanics and failed to demonstrate increased meta- relative risks Wong 2001 Goodinan et al 2004 The asbestos exposure experienced by French car mechanics may lead to pleural plaques The low prevalence of malignant asbestos diseases despite the use of HRCT which is a very sensitive diagnostic tool is in favor of low cumulative exposure to asbestos in the study population Our data are also consistent with the results of a recently published population control study Rolland et al 2010 that reported a slight but not significant increased risk of pleural mesothelioma in male car mechanics odds ratio = 1.50 95 confidence interval 0.76-2.95 FUNDING The Caisse nationale d'assurance maladie des travailleurs salari^'sD^'partementdes risques professionnels Caisse r^'gionaled'assurance maladie d'Ile de France 60 J. 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