[1] Tufts Univ, Dept Internal Med, St Elizabeth Med Ctr, Boston, MA 02111 USA
[2] Boston Univ, Sch Med, Sect Endocrinol Diabet & Nutr, Boston, MA 02118 USA
[3] Univ Calif Los Angeles, David Geffen Sch Med, Dept Med, Div Endocrinol, Los Angeles, CA 90095 USA