End-stage renal disease among silica-exposed gold miners. A new method for assessing incidence among epidemiologic cohorts
G. M. Calvert, K. Steenland and S. Palu
National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio 45226, USA. jac6@cdc.gov
OBJECTIVE: To examine the association between silica exposure and end-stage
renal disease (ESRD). DESIGN: Retrospective cohort study. PARTICIPANTS: A
cohort of 2412 white male gold miners was studied. Eligible gold miners
worked underground for at least 1 year between 1940 and 1965 in a South
Dakota gold mine and were alive on January 1,1977. Of primary interest was
exposure to silica. METHODS: The ESRD Program Management and Medical
Information System (PMMIS) was used to identify members of the gold mine
cohort who had treated ESRD and to create a US rate file for treated ESRD.
The ESRD incidence among the gold miners was compared with that in the US
population. RESULTS: Based on the 11 cohort members identified with treated
ESRD, the risk for ESRD in the cohort was elevated (standardized incidence
ratio [SIR], 1.37; 95% confidence interval [CI], 0.68-2.46). The risk was
greatest for nonsystemic ESRD (ESRD caused by glomerulonephritis or
interstitial nephritis) for which the SIR was 4.22 (95% CI, 1.54-9.19),
increasing to 7.70 (95% CI, 1.59-22.48) among workers with 10 or more years
of employment underground. CONCLUSIONS: To our knowledge this is the first
epidemiologic study to examine ESRD incidence in an occupational cohort.
This study provides evidence that silica exposure is associated with an
increased risk for ESRD, especially ESRD caused by glomerulonephritis. This
study also demonstrates the usefulness of the ESRD PMMIS to assess ESRD
risk among cohorts exposed to potential nephrotoxins.
