[1] Southern Illinois Univ, Dept Populat Sci & Policy, Sch Med, 201 E Madison St,POB 19664, Springfield, IL 62794 USA
[2] St Louis Univ, Sch Med, Dept Internal Med, St Louis, MO USA
[3] St Louis Univ, Canc Ctr, St Louis, MO 63103 USA
[4] St Louis Univ, Sch Med, Dept Otolaryngol Head & Neck Surg, St Louis, MO USA