Cadmium and lung cancer mortality accounting for simultaneous arsenic exposure
- Robert M Park1,
- Leslie T Stayner1,2,
- Martin R Petersen3,
- Melissa Finley-Couch1,4,
- Richard Hornung5,
- Carol Rice6
- 1National Institute for Occupational Safety and Health, Education and Information Division, Cincinnati, Ohio, USA
- 2Department of Epidemiology, School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA
- 3National Institute for Occupational Safety and Health, Division of Surveillance, Hazard Evaluation and Field Studies, Cincinnati, Ohio, USA
- 4Patheon Pharmaceuticals, Inc., Reading, Ohio, USA
- 5Division of Emergency Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati OH, USA
- 6Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
- Correspondence to Robert M Park, National Institute for Occupational Safety and Health (NIOSH), Risk Evaluation Branch, 4676 Columbia Parkway, C-15, Cincinnati, OH 45226, USA;
Contributors The study was designed by LTS and RMP. Data preparation was contributed by MRP and MF-C. Exposure assessment was performed primarily by MF-C and CR. Data analysis was performed by RMP, MRP, LTS and RH. Manuscript preparation was by RMP. RMP and all authors contributed to review and editing of the manuscript.
- Accepted 11 November 2011
- Published Online First 22 January 2012
Objectives Prior investigations identified an association between airborne cadmium and lung cancer but questions remain regarding confounding by arsenic, a well-established lung carcinogen.
Methods A cadmium smelter population exhibiting excess lung cancer was re-analysed using a retrospective exposure assessment for arsenic (As), updated mortality (1940–2002), a revised cadmium (Cd) exposure matrix and improved work history information.
Results Cumulative exposure metrics for both cadmium and arsenic were strongly associated making estimation of their independent effects difficult. Standardised mortality ratios (SMRs) were modelled with Poisson regression with the contribution of arsenic to lung cancer risk constrained by exposure–response estimates previously reported. The results demonstrate (1) a statistically significant effect of Cd independent of As (SMR=3.2 for 10 mg-year/m3 Cd, p=0.012), (2) a substantial healthy worker effect for lung cancer (for unexposed workers, SMR=0.69) and (3) a large deficit in lung cancer mortality among Hispanic workers (SMR=0.27, p=0.009), known to have low lung cancer rates. A supralinear dose-rate effect was observed (contribution to risk with increasing exposure intensity has declining positive slope). Lung cancer mortality was somewhat better predicted using a cadmium burden metric with a half-life of about 20–25 years.
Conclusions These findings support an independent effect for cadmium in risk of lung cancer mortality. 1/1000 excess lifetime risk of lung cancer death is predicted from an airborne exposure of about 2.4 μg/m3 Cd.
- exposure modelling
- healthy worker effect
- Hispanic workers
- Poisson regression
- risk assessment
Disclaimer The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.