[1] Portland VA Med Ctr, Portland Ctr Study Chron Comorbid Phys & Mental D, Portland, OR 97207 USA
[2] Oregon Hlth & Sci Univ, Dept Psychiat, Portland, OR 97201 USA
[3] Oregon Hlth & Sci Univ, Dept Publ Hlth & Prevent Med, Portland, OR 97201 USA
[4] Oregon Hlth & Sci Univ, Ctr Res Occupat & Environm Toxicol, Portland, OR 97201 USA
[5] Minneapolis Vet Affairs Med Ctr, Ctr Chron Dis Outcomes Res, Minneapolis, MN USA
[6] Univ Minnesota, Dept Med, Minneapolis, MN 55455 USA