[1] Johns Hopkins Med Inst, Dept Med, Baltimore, MD 21205 USA
[2] Johns Hopkins Med Inst, Dept Epidemiol, Baltimore, MD 21205 USA
[3] NCI, Lab Genome Divers, Frederick, MD 21701 USA
[4] NCI, Viral Epidemiol Branch, Div Canc Epidemiol & Genet, Rockville, MD USA
[5] Univ Alabama Birmingham, Dept Epidemiol, Birmingham, AL USA
[6] New York Presbyterian Hosp, Cornell Med Ctr, Dept Pediat, New York, NY USA