[1] Inst Nacl Nutr Salvador Zubiran, Clin Epidemiol Unit, Mexico City 14000, DF, Mexico
[2] Inst Nacl Nutr Salvador Zubiran, Dept Internal Med, Mexico City 14000, DF, Mexico
[3] Inst Nacl Nutr Salvador Zubiran, Dept Immunol & Rheumatol, Mexico City 14000, DF, Mexico