1. Department of NutritionUniversity of North Carolina at Chapel HillChapel HillNorth Carolina27599–7400USA
2. Department of RadiologyUniversity HospitalBoston University School of MedicineBostonMassachusetts02118USA
3. Department of MedicineRenal DivisionBoston City HospitalBoston University School of MedicineBostonMassachusetts01003USA
4. Department of Medicine, Section of GastroenterologyUniversity HospitalBoston University School of MedicineBostonMassachusetts02118USA
5. Department of Food Science and NutritionUniversity of Massachusetts at AmherstAmherstMassachusetts01003USA
6. Department of Epidemiology and BiostatisticsBoston University School of Public HealthBostonMassachusetts02118USA