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FILE NAME Brakes BRK DATE 2004 DOC BRK143 DOCUMENT DESCRIPTION Letters to the Editor American Journal of Industrial Medicine RE Asbestos in Brakes Exposure and Risk of Disease AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 315-318 2004 Letter to the Editor RE Asbestos in Brakes Exposure and Risk of Disease To the Editor Dr. Teta has claimed that my review of the issues surrounding the ability of asbestos to cause disease in persons exposed to asbestos from brakes does not meet her standards of equivocal or evidence Dr. Teta's comments are related only to mesothelioma a sentinel disease for asbestos exposure Mullan and Murthy 1991 while my paper discusses all asbestos diseases Dr. Teta asks if consistency in epidemiological studies that suffer from imprecision justify a conclusion that the " evidence is equivocal As Ahlborm et al 1990 report It should however be of equal importance evaluate those studies which do not suggest any effects of a particular exposure on the risk of disease i.e. studies in which the effect measured is estimated to be near the null value In my paper I have evaluated such studies and have pointed out why we cannot rely solely on them for determination of cause and the reason why the epidemiology is equivocal evidence recognizes much more than just epidemiology as defined by the Agency for Toxic Substances and Disease Registries ATSDR in making causal associations I do point out the inherent limitations of human observational data and place it in context with the experi- mental data as well as the available exposure data As pointed out by Dr. Sven Hernberg Editor Emeritus of the Scandinavian Journal Work Environment and Health A truly negative study must ( be large ii be sensitive and iii have documented exposure data Hernberg 1981 One of the most widely acclaimed methodologies for determining cause and effect for general causation was proposed by Sir Austin Bradford Hill in 1965 Hill 1965 In using this methodology researchers are asked to evaluate Dr. Lemen is retired Assistant Surgeon General USPHS and retired Deputy Director and Acting Director NIOSH and has testified as a plaintiff's expert in brake exposure cases Correspondence to Richard A. Lemen 241 Rose Ridge Court Canton GA 30115 mail richard@richad@rlemn.rorg raiclhaerdm@eranle.meon.rorgg Accepted 26 May 2004 DOI ajim.20061 Published online in Wiley InterScience www.interscience.wiley.com nine areas of consideration strength of association temporality biologic gradient consistence specificity biologic plausibility coherence experimental evidence and analogy As Hill noted one of my nine view points can bring indisputable evidence for or against the cause and effect hypothesis and none can be required as a sine qua non Instead he emphasized that the responsibility for making causal judgments rested with a scientific evaluation of the totality of the data He further acknowledged that decisions on causation must be made in the absence of perfect data Dr. Teta has chosen to base her criticisms of my paper without a through review of other factors as suggested by Prof. Hill Let us look at these nine criteria individually in deter- mining whether the data are equivocal and whether the weight of the evidence is lacking in supporting the contention of no relationship with exposure to brakes containing asbestos and the probability of asbestos disease First strength of association is a reflection of the strength of effect in a given study The epidemiological studies conducted to date have suffered from a variety of impressions and confounders as I have pointed out and thus cannot be used by themselves to justify a effect conclusion Second temporality requires that the cause precede the effect In each of the studies referenced by myself and Dr. Teta this has been true Third biologic gradient is the existence of a dose- response relationship for the proposed effect combination Experimental studies and epidemiological studies of asbestos have demonstrated such a response relationship Specifically the studies of brake workers that have examined this issue have shown this response effect for example Iwatsubo et al 1998 clearly came to this conclusion Fourth consistency requires that a proposed effect be observed repeatedly under different circumstances While some of the epidemiology studies have been consistent in 1 evidence- evidence analysis involves the balanced review and integration of relevant exposure toxicologic epidemiologic medical and health outcome data to help determine whether exposures to contaminant levels under specific conditions might result in harmful effects ATSDR 2004 '2004 Wiley Inc. 316 Lemen their lack of significance they have also been consistent in their lack of strength to detect an effect either due to size confounders or lack of sufficient work histories Fifth specificity requires that each cause have a single effect This is rarely a useful criterion when dealing with environmental carcinogens because most of them cause more than one type of cancer Monson 1996 Such is the case with report excesses in lung cancer and bronchus ICD for all age groups except ages 20-29 above 1.0 in the Automobile Mechanics and Repair Workers category 472 They also report seven cases of mesothelioma of the pleura with six of them occurring in the age group that could potentially have the longest latency age group 70-79 PMR = 184 As indicated in the Technical Notes associated with the exposure to asbestos Sixth biologic plausibility seeks to determine if the theory of causation fits known mechanisms of injury causation While it is impossible to have a complete understanding of the mechanisms of cancer causation the Occupational Mortality Database of the Washington State Department of Health from which Petersen and Milham 1980 and Milham and Ossiander 2001 data come from PMRs are of greatest value in studies where mortality rates cannot be calculated due to a lack of information biologic facts known about the various asbestos fibers are clear that they cause both malignant and malignant diseases in experimental systems animals and humans on the population at risk particularly exposure history www3.doh.wa.gov/OCCMORT/HTML/OMtechnotes.htm 3/16/2004 Seventh coherence asks if the causal theory is not inconsistent with what is already known of the injury or If Dr. Teta is referring to not including these papers into my count of mesotheliomas then I thank her since the disease There is no biologic argument that explains why omitted articles add at least another 49 cases to the list of asbestos is incapable of causing asbestosis lung cancer or mesothelioma in one person while not in another Eighth experimental evidence can consist of laboratory mesotheliomas reported among persons potentially exposed to asbestos from brakes Olsen and Jensen 1987 Coggon et al 1995 Milham and Ossiander 2001 studies animal studies controlled clinical trials or observational pathology studies The data in my paper support such The Coggon et al 1995 paper relies only on the occupation as listed on the death certificate which can be evidence misleading since a thorough examination of the decedents Ninth analogy asks if epidemiological and other studies have established that an environmental exposure analogous entire work history and their potential for exposure through home related brake work must be considered Also it must be to the exposure being considered may cause diseases similar considered to those reported for the exposure being 2004 clearly supports this analogy Lemen Dr. Teta states that Two other negative control studies were not discussed both of which examined the risk of mesothelioma in vehicle mechanics excluding men who kept in mind that PMR analysis is not equivalent to establishing a relative risk RR or an odds ratio OR and that they only measure relative frequency of a particular cause among all causes of death in the data set analyzed Colton and Clapp 2000 While this study reports PMRS of 46 12 deaths from pleural cancer 88 3 deaths from also worked in occupations known to pose a mesothelioma peritoneal cancer and 80 2 deaths from asbestosis the risk due to asbestos exposure McDonald and McDonald authors have not given the deaths from all causes in this 1980 Agudo et al 2000 The McDonald and McDonald category of motor mechanics as they have for the other paper simply stated that There were small excesses of some groups they list in their job group table making interpretation occupations but none in the larger notably garage of their findings difficult Important findings of this study maintenance and transport work This paper does not which I did not include in my paper are the author's contribute to our knowledge of brake exposed workers since the paper gave no idea of whether exposures even existed to conclusion that when assuming a linear exposure that pleural mesothelioma may be underestimated brakes in the three categories mentioned such an assumption Olsen and Jensen 1987 report on 93,810 cancer cases is pure speculation without giving detailed exposure data by occupation in Denmark for the years 1970-1979 While Agudo et al 2000 is included in my paper and as the authors this study does not report specific cancers for brake repair suggest the mechanics motor vehicles category does have workers the data do support an excess of mesothelioma and risk of asbestos exposure however the numbers were quite lung cancer in occupations that may have included brake small three cases from which to draw causal relationships repair workers however there is no way to specifically and this reason I included them only in my list of total cases reported identify brake repair exposures For example out of a total of 426 cases of mesotheliomas the authors found that the SPIR When Dr. Teta uses PMR less than 1.0 is not clear for transport and communications to have 27 observed to what diseases or studies she is referring Take for example mesotheliomas when only 18.1 were expected Excesses a Petersen and Milham 1980 who report an increase for the automobile and repair category 472 for lung cancer a disease causally associated with asbestos exposure In a later analysis of the same data base Milham and Ossiander 2001 were also found when looking at subgroups of transport and storage Most of the subgroups experienced elevated risks of mesothelioma with 21 cases observed and 13.5 expected SPIR 155 95 CI 101-238 For the category of repair of Letter to the Editor 317 motor vehicles and motorcycles 34 lung cancers were observed but were not significant and no mesotheliomas were observed The question remains how many performed brake work versus how many did not Further analysis needs to be done to identify specific exposures to asbestos from brakes before this study can contribute to our knowledge concerning brake repair workers and potential diseases from asbestos While mesothelioma accounts for only 0.3 of the total cancers during this period in Denmark the authors say a substantial increase of mesothelioma in incidence has taken place since the inception of the Danish Cancer Registry in 1942. association exists between brake exposures from asbestos As stated by Phil Alderson Associate Director of the UK Cochrane Centre We need to create a culture that is comfortable with estimating and discussing uncertainty Alderson 2004 Therefore the conclusions of my paper can not be ignored by the serious researcher in determining the causal association between asbestos exposures to brake workers and disease Richard A. Lemen PhD MSPH REFERENCES Hodgson et al 1997 like the other surveillance data base studies is quite useful for evaluating overall general categories of cancer mortality trends but not specifically useful when looking at very specific occupational categories or where the risks may be small The authors report PMRs for 27 groups of males 16-74 and have a table of 25 job groups where the PMRs exceeded 100. Motor mechanics were not included in this list and puts them into the lower category The authors point out that the confidence interval for motor mechanics is wide It should be noted that Where risks are small P values may well mislead confidence intervals are likely to be wide indicating considerable uncertainty Altman and Bland 1995 The lack of detailed occupational histories again is a problem with this study Does this mean no risk Agudo A Gonz^lezCA Bleda MJ Ramirez J Hern^ndezS L^pezF. Calleja A Panad^sR Turuguet D Escolar A Baltr^nM Gonz^lez- Moya JE 2000. Occupation and risk of malignant pleural mesothelioma A control study in Spain Am J Ind Med 159 161859 168 Ahlborm A Axelson O Hansen ES Hogstedt C Jensen UJ Olsen J. 1990. Interpretation of negative studies in occupational epidemiol- ogy Scand J Work Environ Health 153 157 Alderson P. 2004. Absence of evidence is not evidence of absence We need to report uncertain results and do it clearly BMJ 476 477 Altman DG Bland JM 1995. Absence of evidence is not evidence of absence BMJ 485 ATSDR 2004. Chapter 8 Health effects evaluation Weight evidence analysis In Public health assessment guidance manual update Atlanta GA Agency for Toxic Substances and Disease Research United States Public Health Service Department of Health and Human Services Dr. Teta states that she and her colleagues obtained data Coggon D Inskip H Winter P Pannett B. 1995. Differences in occu- from the Spirtas et al 1985 study using the SEER database and after analysis found no associations with brake work pational mortality from pleural cancer peritoneal cancer and asbestosis Occup Environ Med 775 777 citing a paper in press by Hessel et al 2004 I would caution that without detailed occupational histories many specific Colton T Clapp RW 2000. Proportional Mortality Study In Benichou J Armitage P editors Encyclopedia of epidemiological methods Wiley reference series in biostatistics UK John Wiley & Sons Ltd. occupational exposures can be overlooked Take for example the analysis by Pinto et al 1995 where nine cases of mesothelioma diagnosed at their Institute which would have gone into the idiopathic category had not diligent interviews with the patients and their relatives by a trained medical doctor been conducted Does the Hessel et al 2004 Hernberg S. 1981. Negative results in cohort studies to recognize fallacies Scand J Work Environ Health Suppl 121-126 Hessel PA Teta MJ Goodman M. 2004. Mesothelioma among brake mechanics An expanded analysis ofa control study Risk Analysis in press Hill B. 1965. The Environment and disease Association or causation study meet such through an examination Without being able Proc R Soc Med 295 299 to examine a paper in press or Letter to MJ Teta from JT Hodgson JT Peto J Jones JR Matthews FE 1997. Mesothelioma Walker of NIOSH an answer to this question is impossible and leaves me unable to make further comment Walker mortality in Britain Patterns by birth cohort and occupation Ann Occup Hyg 129 133 2002 While I agree with Dr. Teta that epidemiological studies provide the best data for causation which she contends IPCS International Program on Chemical Safety 1998. Env Health Criteria 203 Chrysotile Asbestos XXX World Health Organization p 107 a have been done however it is not adequate to rely upon them when they suffer from inadequacies She points out Iwatsubo Y Pairon JC Boutin Orlowski E Galateau F mesothelioma response C Menard O Massin N Caillaud D Bignon J Brochard P. 1998. Pleural relation at low levels of asbestos e ... ignoring or misrepresenting the available evidence from epidemiological studies cannot be defended When one exposure in a French population control study Am J Epidemiol 133 142 looks at the true evidence as I have in my paper Lemen R. 2004. Asbestos in brakes Exposure and risk of disease Am J j the five million people whom Nicholson et al Ind Med 229 23E7rrata In the text on page 234 left column 1984 last paragraph the citation of Anderson et al 1973 should read estimated to have been vehicle mechanics in the US at some Henderson 2000 f time in their careers deserve no less than a through review f of the all the evidence before determining that no causal MAmceDroincaaldCaAnD cerMc1D6on5a0 ld-J1C6159860. Malignant mesothelioma in North 318 Lemen Milham S Ossiander E. 2001. Occupational mortality in Washington State 1950-1999 Epidemiology Office Washington State Department of Health Monson RR 1996. Occupation 18. In Cancer epidemiology and prevention 2nd edn Schottenfeld D Fraumeni JF Jr. editors New York & Oxford Oxford University Press pp 373-405 Mullan RJ Murthy LM 1991. Occupational sentinel health events An dated list for physician recognition and public health surveillance Am J Ind Med 775 799 Nicholson WJ Daum SM Lorimer WV Velez H Lilis R Selikoff IJ Miller A Anderson HA Fischbein SA Holstein EC Rom WN Rosenman K Todaro JD Cheng W Li V Tarr DT 1984. Investigation of health hazards in brake lining repair and maintenance workers occupationally exposed to asbestos National Institute for Occupational Safety and Health NIOSH prepared by Mt. Sinai School of Medicine CUNY New York August Olsen JH Jensen OM 1987. Occupation and risk of cancer in Denmark An analysis of 93,810 cancer cases 1970-1979 Scand J Work Environ Health Suppl 1 91 Petersen GR Milham S. 1980. Occupational mortality in the state of California 1959 196N1IOSH Research Report 33353 Pinto C Soffritti M Maltoni C. 1995. Ignored occupational risks of asbestos mesotheliomas Med Lav 484 489 Spirtas R Keehn R Wright W Stark A Beebe G Dickson E. 1985 Mesothelioma risk related to occupational or other asbestos exposure Preliminary results from a control study Am J Epidemiol 518 Walker JT 2002. Letter to MJ Teta from JT Walker regarding inquiry about PMRs for auto mechanics with attached data sheets Department of Health and Human Services DHHS Public Health Service National Institute for Occupational Safety and Health AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 312-314 2004 Letter to the Editor RE Asbestos in Brakes Exposure and Risk of Disease To the Editor In a recently published review article Dr. Lemen attempted to summarize the data on asbestos exposure from brake work and the risk of mesothelioma Lemen 2004 He concluded that the epidemiological evidence is equivocal My colleagues and I conducted a study in the early 1980s that Dr. Lemen cited as one of the studies that supported this opinion Teta et al 1983 We identified one case and five controls employed in the category automotive repair and related services 0.65 95 CI 0.08-5.53 Ours is one of a large number of epidemiological studies that have examined mesothelioma risk among vehicle mechanics or those involved in brake repair McDonald and McDonald 1980 Petersen and Milham 1980 Spirtas et al 1985 Olsen and Jensen 1987 Woitowitz and R^delsperger 1994 Coggon et al 1995 Hodgson et al 1997 Teschke et al 1997 Agudo et al 2000 Milham and Ossiander 2001 NIOSH 2002 While individual studies such as ours may be imprecise as a result of small numbers of individuals with a history of vehicle repair the best estimates of risk from the available analytical studies are consistently below the null value for this occupation This does not justify a conclusion that the evidence is equivocal We acknowledged in our study the fact that our work histories were based on city directories and death certificates Dr. Lemen We did discuss however that we may have missed occupationally exposed cases and controls and the issue of random misclassification Bias toward the null OR = 1.0 if it existed would imply an unlikely true OR of less than 0.65 that we reported for the auto repair category This is in contrast to categories with ORs greater than 1.0 such as plumbers and pipefitters in which the true OR may be greater than the 3.87 we reported if bias toward the null had been operating for this group It is reassuring that the large number of studies that came after our 1983 report were consistent with ours in reporting no increased risk for vehicle mechanics using an interview approach to ascertain work history So, Rather than relying on evidence evalua- tion of the epidemiological data Dr. Lemen emphasized recognized challenges in conducting occupational case- control studies such as small numbers of cases and incomplete work histories in selected individual studies As epidemiologists we recognize the inherent limitations of human observational data and therefore require , that conclusions be drawn from a body of evidence not from a single study Other relevant studies in addition to ours have been mischaracterized in Dr. Lemen's review He discussed the study by Woitowitz and R^delsperger 1994 that also showed no increased risk for motor vehicle mechanics and may not be complete but we went to great lengths to show comparability of completeness between cases and e He attributed to them the conclusion that if there controls We did not conclude that lack of detailed was a mesothelioma risk it could not be detected by information regarding the residual cases could obscure the true number of occupationally exposed cases as stated by their methodology e But what the authors really said was From these results there is no evidence that car mechanics are Dr. Teta has served as an expert witness in friction brake litigation Her employer Exponent Inc. receives funding for her work in this area from Ford General Motors and Daimler Chrysler Correspondence to M. Jane TetaExponent Health Group 420 Lexington Avenue Suite 408 New York NY 10172. mail Jteta@exponent.com Accepted 26 May 2004 DOI ajim.20060 Published online in Wiley InterScience www.interscience.wiley.com exposed to an increased risk of mesothelioma even if they do brake repairs but asbestos exposure in other employment is an important confounding factor so that if there is a mesothelioma risk for car mechanics but it were small it would not be detectable Woitowitz and R^delsperger 1994 This is a fair statement by the authors that their study alone could not rule out a small risk '2004 Wiley Inc. CO cre wh et disc in \ -- asb et a data wer Mil 199 NIC mes al mec asse expi wor 2 asbe iden fron Dr. 1 of th stud colle 198 both ing 1 in F no e brak due Letter to the Editor 313 oe Mee end ar nee eet en an ects Sad Another negative control study that took potential confounding exposures into account also reported no increased risk for vehicle mechanics and specifically those who were involved in brake installation and repair Teschke et al 1997 e The authors clearly stated One a priori risk occupation had a reduced risk estimate vehicle mechanics and as in the previous analysis brake installation and repair did not appear to be associated with mesothelioma e Dr. Lemen summarized this study with the statement The authors ... acknowledge their findings are based on small numbers of cases and any judgments about any causal associations would be speculative Teschke et al 1997 did make such a statement but in reference to some of their positive findings exposures are known to exist The presence of these cases is particularly relevant for those in common occupations Nicholson et al estimated that in 1984 there were five million people in the US who had been vehicle mechanics at some time in their careers Nicholson et al 1984 Whether case reports of mesothelioma in men who at some time worked as vehicle mechanics are indicative of an occupational risk related to this occupation is best determined from epidemiological studies that include comparison populations and ideally the ability to address confounding by other asbestos occupations These studies have been conducted and the results are not consistent with the implications of this review article Reliance on case reports of mesothelioma among men who worked at some time as a vehicle mechanic while ignoring or misrepresenting the available evidence from epidemiological studies cannot be defended The statement was not referring to occupations not associated with mesothelioma in their study e.g. vehicle mechanics M. Jane Teta DrPH MPH Exponent Health Group Two other negative control studies were not discussed both of which examined the risk of mesothelioma in vehicle mechanics excluding men who also worked in occupations known to pose a mesothelioma risk due to asbestos exposure McDonald and McDonald 1980 Agudo et al 2000 The numerous studies based on surveillance databases all of which reported PMR less than 1.0 were also not included in his review Petersen and Milham 1980 Olsen and Jensen 1987 Coggon et al 1995 Hodgson et al 1997 Milham and Ossiander 2001 420 Lexington Avenue Suite 408 New York New York 10172 REFERENCES Agudo A Gonz^lez CA Bleda MJ Ramirez J Hern^ndez S L^pezF Calleja A Panad^sR Turuguet D Escolar A Baltr^nM Gonz^lezJE 2000. Occupation and risk of malignant pleural mesothelioma A control study in Spain Am J Ind Med 159- 168 NIOSH 2002 Dr. Lemen placed greater weight on case reports of mesothelioma in vehicle mechanics including case counts Coggon D Inskip H Winter P Pannett B. 1995. Differences in occupational mortality from pleural cancer peritoneal cancer and asbestosis Occup Environ Med 775-777 at least 165 from negative control studies of vehicle mechanics and from friction products manufacturing and asserted that these cannot be due to chance or ambient air exposures He apparently dismissed 1 some cases who also worked in some classic asbestos occupations and 2 the known occurrence of cases with no documented asbestos exposure First in our 1983 investigation we identified an average of over three jobs for study subjects from city directories and death certificates Teta et al 1983 Dr. Lemen himself noted that an overwhelming majority of those who did brake repair work in the Spirtas et al 1985 study had also worked as insulators and shipbuilders My colleagues and I obtained the data from the Spirtas et al 1985 study and examined this issue looking at brake work both occupationally and occupationally while adjusting for other occupational exposures Hessel et al 2004 in press The results were negative overall and showed no evidence of increased risk with increasing duration of Hessel PA Teta MJ Goodman M. 2004. Mesothelioma among brake mechanics An expanded analysis of a control study Risk Analysis 547 552 Hodgson JT Peto J Jones JR Matthews FE 1997. Mesothelioma mortality in Britain Patterns by birth cohort and occupation Ann Occup Hyg 129-133 Lemen RA 2004. Asbestos in brakes Exposure and risk of disease Am J Ind Med 229 237 McDonald AD McDonald JC 1980. Malignant mesothelioma in North America Cancer 1650 1656 Milham S Ossiander E. 2001. Occupational mortality in Washington State 1950-1999 Epidemiology Office Washington State Department of Health Nicholson WJ Daum SM Lorimer WV Velez H Lilis R Selikoff IJ Miller A Anderson HA Fischbein SA Holstein EC Rom WN Rosenman K Todaro JD Cheng W Li V Tarr DT 1984. Investigation of health hazards in brake lining repair and maintenance workers occupationally exposed to asbestos National Institute for Occupational Safety and Health NIOSH prepared by Mt. Sinai School of Medicine CUNY New York August brake work Second idiopathic mesotheliomas and those due to occupational or unrecognized occupational NIOSH 2002. Letter to MJ Teta from JT Walker regarding inquiry about PMRS for auto mechanics with attached data sheets Department of 314 Teta Health and Human Services DHHS Public Health Service National Institute for Occupational Safety and Health Olsen JH Jensen OM 1987. Occupation and risk of cancer in Denmark An analysis of 93,810 cancer cases 1970-1979 Scand J Work Environ Health Suppl 1 91 Petersen GR Milham S. 1980. Occupational mortality in the state of California 1959-1961 National Institute for Occupational Safety and Health Research Report 33353 Spirtas R Keehn R Wright W Stark A Beebe G Dickson E. 1985 Mesothelioma risk related to occupational or other asbestos exposure Preliminary results from a control study Am J Epidemiol 518 Teschke K Morgan MS Checkoway H Franklin G Spinelli JJ van Belle G Weiss NS 1997. Mesothelioma surveillance to locate sources of exposure to asbestos Can J Public Health 88 163 168 Teta MJ Lewinshon HC Meigs JW Vidone RA Mowad LZ Flannery JT 1983. Mesothelioma in Connecticut 1957 197o7ccupational and geographic associations J Occup Med 749-756 Woitowitz HJ R^delsperger K. 1994. Mesothelioma among car mechanics Ann Occup Hyg 635 638 o i Ean I S t h 022 Ac w