1. Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, Colorado, USA
2. Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA
3. Small Area Health Statistics Unit, Department of Epidemiology and Public Health, Imperial College London, London, United Kingdom