[1] Birmingham VA Med Ctr, Med Serv, 700 19th St S, Birmingham, AL 35233 USA
[2] Univ Alabama Birmingham, Sch Med, Dept Med, 510 20th St South, Birmingham, AL 35294 USA
[3] Univ Alabama Birmingham, Sch Publ Hlth, Div Epidemiol, 1720 Second Ave South, Birmingham, AL 35294 USA
[4] Univ Alabama Birmingham, Fac Off Tower 805B,510 20th St S, Birmingham, AL 35294 USA
[5] VA Pittsburgh Healthcare Syst, Pittsburgh, PA USA
[6] Phoenix VA Med Ctr, Phoenix, AZ USA
[7] Univ Ottawa, Sch Rehabil Sci, Fac Hlth Sci, Ottawa, ON, Canada
[8] Childrens Hosp, Eastern Ontario Res Inst, Ottawa, ON, Canada
[9] Univ Ottawa, Fac Med, Dept Pediat, Ottawa, ON, Canada
[10] Oregon Hlth & Sci Univ, VA Portland Hlth Care Syst, Portland, OR 97201 USA
[11] Oregon Hlth & Sci Univ, Dept Med, Portland, OR 97201 USA