Job-exposure matrix (JEM) validity on crystalline silica among systemic sclerosis patients

Abstract

Background: Systemic sclerosis (SSc) is the connective tissue disease with the highest individual mortality. Crystalline silica is known to be an occupational risk factor for SSc. To assess past crystalline silica exposure, we aimed to study the validity of a job exposure matrix (JEM) to assess occupational exposure to crystalline silica compared to specific occupational interviews in two populations of SSc patients.

Aims: To demonstrate the reliability of JEM for the assessment of occupational exposure to hazards such as silica, in severe rare disorders like SSc.

Methods: Patients from two university hospital centres underwent standardized assessment of occupational silica exposure and collected job histories through face-to-face interviews. A JEM from the French program Matgéné was used to assess silica exposure and compared to the standardized interview results. Standard metrics were computed for evaluate the accuracy of JEM.

Results: 67 participants from Rennes, and 119 from Tours were included, with respectively 10.5% and 18.0% of patients with silica exposure based on the results of the interview. The JEM with 50% probability cut-off had a good performance when compared with the classic assessment method. A cumulative exposure index from JEM over 250 had an area under the curve between 0.76 and 0.79 and also a very high positive likelihood ratio (17.14 and 10.29).

Conclusions: Despite limitations inherent to JEMs and associated validation methods, the JEM used in this setting provided accurate results to assess occupational exposure to crystalline silica for clinical purposes such as in SSc patients, especially to detect positive cases.