1. Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA
2. Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
3. Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA
4. Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA
5. Cardiovascular Epidemiology Research Unit, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA