[1] NIDDKD, Div Digest Dis & Nutr, NIH, Bethesda, MD 20892 USA
[2] Univ Nebraska, Med Ctr, Omaha, NE USA
[3] Univ Pittsburgh, Grad Sch Publ Hlth, Pittsburgh, PA USA
[4] Mayo Clin & Mayo Fdn, Rochester, MN 55905 USA
[5] Univ Calif San Francisco, San Francisco, CA 94143 USA