[1] Univ Alabama Birmingham, Dept Epidemiol, Birmingham, AL 35294 USA
[2] Kaiser Permanente Southern Calif, Dept Res & Evaluat, Pasadena, CA 91188 USA
[3] Kaiser Permanente Colorado, Inst Hlth Res, Aurora, CO USA
[4] Colorado Sch Publ Hlth, Dept Epidemiol, Aurora, CO USA
[5] Colorado Permanente Med Grp, Chem Dependency Treatment Serv, Aurora, CO USA
[6] Bernard J Tyson Sch Med, Binswanger, Pasadena, CA USA
[7] Southern Calif Permanente Med Grp, Dept Clin Anal, Pasadena, CA USA
[8] Southern Calif Permanente Med Grp, Reg Reference Labs, Chino Hills, CA USA