[1] Calif Pacific Med Ctr, San Francisco, CA USA
[2] San Francisco Coordianting Ctr, San Francisco, CA USA
[3] Univ Calif San Francisco, Dept Med, San Francisco, CA USA
[4] Univ Calif San Diego, Dept Psychiat, San Diego, CA 92103 USA
[5] Vet Affairs San Diego Healthcare Syst, San Diego, CA USA
[6] Vet Affairs Med Ctr, Minneapolis, MN USA
[7] Univ Minnesota, Minneapolis, MN USA
[8] Univ Pittsburgh, Dept Epidemiol, Pittsburgh, PA 15261 USA
[9] Case Western Reserve Univ, Dept Epidemiol & Biostat, Cleveland, OH 44106 USA
[10] Univ Calif San Diego, Dept Family & Prevent Med, Div Epidemiol, San Diego, CA 92103 USA
[11] Vet Adm Palo Alto Healthcare Syst, Palo Alto, CA USA
[12] Stanford Univ, Palo Alto, CA 94304 USA