Mesothelioma in vehicle mechanics: is the risk different for Australians?
BACKGROUND
The question of whether vehicle mechanics have an increased risk of mesothelioma has important public health implications. Calculations of relative risk using case reports from the Australian Mesothelioma Registry (AMR) indicate increased risks; however, this contrasts with the results of 19 epidemiologic studies that have found no association.


OBJECTIVE
To evaluate potential explanations for the discrepancy of findings from epidemiologic studies and AMR reports.


METHODS
We evaluated three hypotheses as possible explanations for the inconsistency between the AMR-based calculations and the findings from published epidemiologic studies: (i) differences in exposure characteristics of Australian vehicle mechanics versus vehicle mechanics in North America and Europe, (ii) limitations of the AMR data and (iii) errors in the risk calculations based on AMR data. We reviewed available exposure information specific to Australian vehicle mechanics and AMR data, obtained from the Australian National Occupational Health and Safety Commission, for this evaluation.


RESULTS
We did not identify differences in workplace exposures, processes or fibre type among Australian vehicle mechanics compared to vehicle mechanics in other countries. Our analysis of primary AMR data identified several errors in exposure classification and in the assumptions used to calculate relative risk.


CONCLUSIONS
Discrepancies between epidemiologic studies and AMR-based calculations cannot be explained by differences in exposure. These discrepancies are most likely attributable to inadequate occupational information and classification in the AMR from 1986 forward and to erroneous assumptions used to derive relative risk estimates for mesothelioma among Australian vehicle mechanics.
Kelsh
Michael A
MA
Exponent, Inc., 149 Commonwealth Drive, Menlo Park, CA 94025, USA. mkelsh@exponent.com
Craven
Valerie A
VA
Teta
Mary Jane
MJ
Mowat
Fionna S
FS
Goodman
Michael
M
D000395:Air Pollutants, Occupational / Q000633:toxicity; D001194:Asbestos / Q000633:toxicity*; D001315:Australia / Q000453:epidemiology; D001336:Automobiles; D002273:Carcinogens / Q000633:toxicity*; D004812:Epidemiologic Methods; D005060:Europe / Q000453:epidemiology; D006801:Humans; D008297:Male; D008654:Mesothelioma / Q000453:epidemiology / Q000209:etiology*; D009784:Occupational Diseases / Q000453:epidemiology / Q000209:etiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D014481:United States / Q000453:epidemiology
D000395:Air Pollutants, Occupational; D002273:Carcinogens; D001194:Asbestos