[1] Univ Pittsburgh, Dept Epidemiol & Biostat, GSPH, Pittsburgh, PA 15261 USA
[2] Stanford Univ, Sch Med, Stanford, CA 94305 USA
[3] Brigham & Womens Hosp, Boston, MA 02115 USA
[4] Memphis VA Med Ctr, Memphis, TN USA
[5] Case Western Reserve Univ, Sch Med, Cleveland, OH USA
[6] Univ Florida, Coll Med, Jacksonville, FL USA
[7] Mayo Clin, Rochester, MN USA