Document MJDLjQ7z9m5wdo3oKe2RE97Bz

FILE NAME Brakes BRK DATE 2016 DOC BRK251 DOCUMENT DESCRIPTION Journal Editorial - When Are Risk Analyses on Job Titles Informative Ann Occup Hyg 2016 Vol 60 No. 8 913-915 mew047 EDITORIAL When Are Risk Analyses on Job Titles Informative In the January issue of the Annals of Occupational her letter to the editor the issue of interest is whether Hygiene we published a paper by Garabrant et al chrysotile asbestos exposure among mechanics causes 2016a Mesothelioma among Motor Vehicle mesothelioma Mechanics perform a variety of tasks Mechanics An updated review and analyses and not all mechanics will be involved in break repair The paper described an update from a 2004 metaanalyses performed largely by the same authors The Downlade updated analyses included 10 control stud- from ies 1 cohort study and 5 proportional mortality ratio The ones that do in turn may only do so for part of the time Using broad categories of job titles e.g. garage workers auto repair and related services and auto engineers are therefore likely poor proxies of chry- standardized mortality odds ratio OR studies The sotile asbestos exposure As such although the con- http // an hyg results of the analyses indicated that the sum- mary risk estimates were generally < and that no statistically significant increases in mesothelioma were clusion of the paper is correct in that no elevated risks are found among motor vehicle mechanics as a whole this cannot be equated to mean that there is no risk of observed The authors therefore concluded that this mesothelioma among mechanics that were involved in oxfrdjunals analysis of the epidemiologic studies provides break repair and that had potential chrysotile exposure evidence that motor vehicle mechanics including In their answer to the letter to the editor Garabrant et of workers who were engaged in brake repair are not at al 2016b indicated that the results may indicate that an increased risk of mesothelioma Garabrant et al motor vehicle mechanics and brake workers are per- by guest 2016a 2016a This conclusion is similar to the conclusion of the 2004 paper that concluded based on seven studies haps not at increased risk of mesothelioma as they may not have sufficient exposure to observe an increased on of which six studies were also included in the current risk Again this statement is correct at the title level October analyses that employment as a motor vehicle but may not hold for specific subgroups and indi- mechanic does not increase the risk of developing viduals that may have been higher exposed As such 3 2016 mesothelioma Goodman et al 2004 Although there were some methodological differences between the question can and perhaps should be raised in how far based analyses are informative and when the two analyses in how the quality of the stud- similar debate arose during the International Agency ies was scored the two ranking systems showed overall of Research of Cancer IARC on the evaluation of good correspondence and resulted in a similar clas- the carcinogenic risk among firefighters Firefighters sification in quality categories Analyses by quality of are exposed to numerous known carcinogens among the studies did not show an association between study which benzene diesel exhaust formaldehyde and quality and the log OR and of the 10 studies only 2 polycyclic aromatic hydrocarbons IARC 2010 studies had an OR > 1. All together the conclusion of However epidemiological studies based on having a the papers seemed therefore scientifically justified job as a firefighter have rendered heterogeneous results However there is a question in how one should with some indications of elevated risks of testicular and interpret this result As Teschke 2016 pointed out in prostate cancer and Hodgkin lymphoma Based 'The Author 2016 Published by Oxford University Press on behalf of the British Occupational Hygiene Society 913 914 When are risk analyses on job titles informative on the available epidemiological evidence the IARC of the asbestos fibers in this industry have to be exam- expert group concluded that there is limited evidence ined carefully and if identifiable as asbestos have to in humans for the carcinogenicity of occupational be assumed to carry cancer risk even in the absence of exposure as a firefighter Again the scientific evidence supports this statement but similar as to the case of epidemiologic evidence In the case of job titles with no known carcinogenic motor vehicle mechanics the epidemiological results exposures analyses on title levels may be informa- may well have been severely attenuated due to expo- tive and may provide clues to work circumstances and sure misclassification It could be argued that a job in exposures that are detrimental to health A good exam- which known carcinogenic agents are present should ple of such an analysis is rubber workers where there is by definition be defined as an exposure circumstance consistent epidemiological evidence of increased risks that entails carcinogenic risk An evaluation of disease of leukemia lymphoma and cancers of the urinary risk within such job titles is in essence not a hazard bladder also after the ban on napthylamine evaluation but an indirect quantitative risk assessment lung and stomach IARC 2012 In this case analy- question as it will depend on the level and prevalence ses on the title level resulted in the identification Downlade of exposure and the associated risk if a risk at the job- title level can be observed statistically So how should we view these analyses on job titles of increased cancer risks in the rubber manufacturing industry that in turn let to more detailed research on trying to identify the specific agents responsible for the with known carcinogenic exposures Clearly such observed risk Although this has not necessarily led to from analyses cannot be used to inform on the carcino- clearer picture on what is causing cancer in the rubber http genicity of known carcinogenic exposures In other industry it is an example of how analyses on job titles an hyg words we would not based on the absence of an asso- ciation between working as a motor vehicle mechanic can be used to generate new hypotheses Such hypoth- eses would then need to be followed up with more spe- and mesothelioma conclude that there is no associa- cific quantitative studies on potential harmful agents oxfrdjunals tion between chrysotile exposure and mesothelioma In a more sophisticated way one could combine As evidenced in a recent regression analyses on information on job title and quantitative exposure in oig chrysotile exposure and mesothelioma risk there is a a hierarchical regression model Corbin et al 2012 monotonic association between occupational chryso- Such an analysis would decrease the possibility that by tile exposure and mesothelioma risk with no evidence an occupation entailing exposure to known occupa- of a threshold van der Bij et al 2013 These analyses tional carcinogens is rejected while occupations not guest would suggest that motor vehicle mechanics who are entailing exposure to known occupational carcino- on October exposed to chrysotile would be at increased risk for mesothelioma Therefore analyses on job titles that gens would be highlighted Such job titles should be further investigated and are more likely to provide constitute known carcinogenic exposures are only information on the role of new or suspected occupa- 3 useful as to investigate the overall risk as to judge the tional carcinogens To date few studies have however 2016 likelihood and level of exposures within the broad implemented such hierarchical methods category However this is a rather insensitive tool So when are risk analyses on job titles informative as it depends strongly on the validity and power of Analyses on job titles can be informative in the situ- the epidemiological study Using industrial hygiene ation where job titles entail unknown carcinogens or observations and historical measurements may be a a mix of known and unknown carcinogens In these more direct and valid way to determine this The latter situations based analyses can provide infor- also applies to the argument made by Garabrant et al mation on the role of new or suspected occupational 2016b that the absence of an effect may be due to carcinogens However as exposures vary considerably the fact that besides low exposures and potency fib- within job titles depending on their job activities they ers are short in friction materials and that they maybe can at best be regarded as crude measures of exposure degraded by temperature and physical force into even shorter fibers and forsterite Again this may be true but hard to prove based on epidemiological studies by As such positive results may provide new information however null results cannot be used to exclude that there no effect of a known carcinogen within the absence of an effect Again here detailed studies that occupation When are risk analyses on job titles informative . 915 DECLARATION Garabrant DH Alexander DD Miller PE et al 2016b The author declares no conflict of interest relating to the material presented in this editorial Response to letter to the editor mesothelioma among motor vehicle mechanics an updated review and metaanalysis Ann Occup Hyg Roel Vermeulen Institute for Risk Assessment Sciences IRAS Utrecht University Yalelaan 2 3508 TD Utrecht The Netherlands Author to whom correspondence should be addressed Tel 31-30253-9494 mail Goodman M Teta MJ Hessel PA et al 2004 Mesothelioma and lung cancer among motor vehicle mechanics a metaanalysis Ann Occup Hyg 48 309-26 IARC 2010 Painting firefighting and shiftwork In Monographs on the evaluation of carcinogenic risks to humans IARC Monograph No. 98. Lyon France IARC Press r.c.h.vermeulen@uu.nl IARC 2012 Chemical agents and related occupations In Monographs on the evaluation of carcinogenic risks to humans REFERENCES IARC Monograph No. 100F Lyon France IARC Press Teschke K. 2016 Letter to the editor mesothelioma among Corbin M Richiardi I. R Vermeulen et al 2012 Hierarchical motor vehicle mechanics an updated review and meta- Downlade regression for multiple comparisons in a control study of occupational risks for lung cancer PLoS One 7 e38944 Garabrant DH Alexander DD Miller PE et al 2016a analysis Ann Occup Hyg van der Bij S Koffijberg H Lenters V et al 2013 Lung can- cer risk at low cumulative asbestos exposure regres- Mesothelioma among motor vehicle mechanics an updated htfp.r/aonmhyg review and analysis Ann Occup Hyg 60 8-26 sion of the exposure relationship Cancer Causes Control 24 1-12 htp./anhyg oxfrdjunals org by guest on October 3 2016