[1] CNR, Dept Internal Med, Mexico City, DF, Mexico
[2] CNR, Inst Clin Physiol, Metab Unit, Mexico City, DF, Mexico
[3] Amer British Cowdray Hosp, Ctr Estud Diabet, Mexico City, DF, Mexico
[4] Univ Texas, Hlth Sci Ctr, Dept Med, Div Clin Epidemiol, San Antonio, TX USA