[1] Univ Alabama, Dept Epidemiol & Int Hlth, Birmingham, AL 35294 USA
[2] Univ Alabama, Dept Epidemiol & Int Hlth, Birmingham, AL 35294 USA
[3] Univ Alabama, Dept Obstet & Gynecol, Birmingham, AL 35294 USA
[4] Univ Alabama, Dept Med, Birmingham, AL 35294 USA
[5] Chulalongkorn Univ, Dept Med, Bangkok, Thailand
[6] Thai Red Cross AIDS Res Ctr, Bangkok, Thailand