45. Occupational exposure and granulomatosis with polyangiitis: new findings by using a job exposure matrix
Creators: name: Chiappe1, Solange Gonzalez
name: Mahr1, Alfred
name: Knight2, Ann
Publisher: name: Zenodo
Year: 2022
Subjects: Vasculitis
ANCA
Abstracts
Giant Cell Arthritis
MPA
GPA
EGPA
Takayasu
IgA vasculitis

description: <strong>Background:</strong> Study of the environmental risk factors of granulomatosis with polyangiitis (GPA) may be more informative by analysing occupational exposure rather than occupational categories. We investigated occupational exposure associated with GPA incidence among pre-selected Swedish workers. <strong>Methods: </strong>Data were retrieved from the Knight et al. report on occupational risk factors for Wegener’s granulomatosis, a case–control study. The authors selected 32 occupations involving contact with animals and various airway exposures and compared the occupations held before an index date among GPA cases and general-population controls. For our purpose, we converted the reported occupations according to the 1968 International Standard Classification of Occupations and estimated occupational substance exposure by using the online Canadian Job Exposure Matrix (JEM). Then, substances showing the same relative frequency between cases and controls in each physicochemical category were combined. Finally, the frequency of the constituted groups was compared between cases and controls by chi-square test. P&lt;0.05 was considered statistically significant. <strong>Results:</strong> The Knight et al. study identified 392 GPA cases and 3,612 controls holding at least 1 of the 32 studied occupations (odds ratio 1.1, 95% confidence interval 1.0 to 1.3). The JEM estimated that the 32 occupations were exposed to 136 substances distributed among 6 categories of dusts, liquids, gases and fumes. GPA cases were more frequently exposed to a combination of organic gases, liquids and vapours and a combination of organic dusts as compared with controls (31.7% vs 30.5%, p=0.002, and 5.0% vs. 4.6%, p=0.03). Conversely, controls were more frequently exposed to a combination of inorganic fumes, liquids and vapours and a combination of inorganic dusts than cases (5.3% vs. 4.9%, p=0.006, and 7.5% vs. 6.9%, p=0.003). Cases and controls did not differ in exposure to inorganic and organic mixtures or inorganic gases (8.6% vs 8.6%, p=0.99, and 8.4% vs 8.2%, p=0.34). The Table shows substance combinations. <strong>Conclusions:</strong> This large and comprehensive study suggests that GPA incidence could be associated with a combination of organic gases, liquids, vapours and dusts, which agrees with previously reported associations of the disease with farm, livestock or organic solvent exposures. Polycyclic aromatic hydrocarbons were highly represented in the organic group and deserve further investigation as a GPA risk factor. An inverse or no association between GPA incidence and the combined inorganic substances may be related to their attributed adjuvant role. Results are more specific in this supplementary analysis as compared with the original study. However, the population attributable fraction of suggested risk factors for the risk of GPA seems low. A dose–time response analysis may increase the effects of found associations. <strong>Disclosures:</strong> None