[1] Augusta Univ, Dept Populat Hlth Sci, Div Epidemiol, Augusta, GA USA
[2] Augusta Univ, Med Coll Georgia, Inst Prevent & Publ Hlth, Augusta, GA USA
[3] Duke Univ, Dept Populat Hlth Sci, Sch Med, Durham, NC 27708 USA
[4] Univ Alabama Birmingham, Dept Epidemiol, Birmingham, AL USA