[1] BUSM, Med Sect, Boston, MA USA
[2] Boston Univ, Sch Med, Clin Epidemiol Res & Training Unit, Boston, MA 02118 USA
[3] UCSF, Epidemiol & Biostat, San Francisco, CA USA
[4] Univ Iowa, Iowa City, IA USA
[5] Univ Alabama Birmingham, Prevent Med, Birmingham, AL USA
[6] Boston Univ, Sch Med, Clin Epidemiol Res Unit, Boston, MA 02118 USA
[7] BUSM, Boston, MA USA
[8] BUSM, Clin Epidemiol, Boston, MA USA