1 Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD.
2 Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.
3 Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD; Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD. Electronic address: kuni.matsushita@jhu.edu.