[1] Boston Univ, Sch Med, Boston, MA 02118 USA
[2] Kaiser Permanente So Calif, Pasadena, CA 91101 USA
[3] VA Portland Hlth Care Syst, Portland, OR USA
[4] Oregon Hlth & Sci Univ, Portland, OR 97201 USA
[5] Edith Nourse Rogers Mem Vet Adm Hosp, 200 Springs Rd, Bedford, MA 01730 USA