[1] Univ Iowa, Roy J & Lucille A Carver Coll Med, Dept Pathol, Iowa City, IA 52242 USA
[2] Univ Iowa, Roy J & Lucille A Carver Coll Med, Dept Med, Iowa City, IA 52242 USA
[3] Univ Iowa, Roy J & Lucille A Carver Coll Med, Dept Epidemiol, Iowa City, IA 52242 USA
[4] Univ Iowa, Coll Publ Hlth, Iowa City, IA 52242 USA