Occupational exposure to respirable crystalline silica and incident glomerulonephritis.

OBJECTIVES

Occupational exposure to respirable crystalline silica has been suggested by previous studies to increase the risk of kidney-related diseases. This study investigated the association between occupational exposure to crystalline silica and the risk of glomerulonephritis.

METHODS

Prospective cohort study with 2,955,863 Danish workers followed from 1994 to 2015. All cohort members were assigned an annual level of exposure to crystalline silica by linking a job exposure matrix with each individual's work history. We identified cases of glomerulonephritis by ICD-10 codes N00, N01, N02 and N05 in the Danish National Patient Registry. Exposure-response relations were examined for cumulative exposure to silica, highest attained exposure, and exposure duration using a discrete time hazard model. We adjusted for age, sex, calendar year, education and chronic infections and censored when diseases strongly associated with glomerulonephritis occurred.

RESULTS

We identified 3054 cases of glomerulonephritis. Analyses showed no increase in risk with increasing cumulative exposure with an incidence rate ratio (IRR) of 1.01 (95 % confidence interval (CI): 0.97-1.05) per 50 (μg/m3-years). The IRR in the highest exposure tertile compared to the non-exposed group was 1.12 (95 % CI: 0.93-1.35). Comparable results were found for highest attained exposure and exposure duration.

CONCLUSION

Our findings do not suggest a causal relation between occupational exposure to crystalline silica and glomerulonephritis. However, further research is needed to confirm these findings.