1. Department of Environmental and Occupational Health Sciences, and
2. Department of Medicine, University of Washington, Seattle, Washington, USA
3. Department of Mathematics & Statistics, Winona State University, Winona, Minnesota, USA
4. Department of Biostatistics, University of Washington, Seattle, Washington, USA
5. Chronic Disease Epidemiology Group, and
6. Genetics, Environment, & Respiratory Disease Group, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
7. Department of Civil Engineering, University of Minnesota, Minneapolis, Minnesota, USA
8. Department of Epidemiology, University of Washington, Seattle, Washington, USA