OBJECTIVES: We describe the elaboration and sensitivity analyses of a quantitative job-exposure matrix (SYN-JEM) for respirable crystalline silica (RCS). The aim was to gain insight into the robustness of the SYN-JEM RCS estimates based on critical decisions taken in the elaboration process. METHODS: SYN-JEM for RCS exposure consists of three axes (job, region, and year) based on estimates derived from a previously developed statistical model. To elaborate SYN-JEM, several decisions were taken: i.e. the application of (i) a single time trend; (ii) region-specific adjustments in RCS exposure; and (iii) a prior job-specific exposure level (by the semi-quantitative DOM-JEM), with an override of 0 mg/m (3) for jobs a priori defined as non-exposed. Furthermore, we assumed that exposure levels reached a ceiling in 1960 and remained constant prior to this date. We applied SYN-JEM to the occupational histories of subjects from a large international pooled community-based case-control study. Cumulative exposure levels derived with SYN-JEM were compared with those from alternative models, described by Pearson correlation ( (Rp) ) and differences in unit of exposure (mg/m (3) -year). Alternative models concerned changes in application of job- and region-specific estimates and exposure ceiling, and omitting the a priori exposure ranking. RESULTS: Cumulative exposure levels for the study subjects ranged from 0.01 to 60 mg/m (3) -years, with a median of 1.76 mg/m (3) -years. Exposure levels derived from SYN-JEM and alternative models were overall highly correlated (R (p) > 0.90), although somewhat lower when omitting the region estimate ( (Rp) = 0.80) or not taking into account the assigned semi-quantitative exposure level (R (p) = 0.65). Modification of the time trend (i.e. exposure ceiling at 1950 or 1970, or assuming a decline before 1960) caused the largest changes in absolute exposure levels (26-33% difference), but without changing the relative ranking ( (Rp) = 0.99). CONCLUSIONS: Exposure estimates derived from SYN-JEM appeared to be plausible compared with (historical) levels described in the literature. Decisions taken in the development of SYN-JEM did not critically change the cumulative exposure levels. The influence of region-specific estimates needs to be explored in future risk analyses.
Auteur : Peters S, Kromhout H, Portengen L, Olsson A, Kendzia B, Vincent R, Savary B, Lavoue J, Cavallo D, Cattaneo A, Mirabelli D, Plato N, Fevotte J, Pesch B, Bruning T, Straif K, Vermeulen R
The Annals of occupational hygiene, 2013, vol. 57, n°. 1, p. 98-106