[1] Univ N Carolina, Gillings Sch Global Publ Hlth, Dept Epidemiol, Chapel Hill, NC USA
[2] Univ N Carolina, Injury Prevent Res Ctr, Chapel Hill, NC USA
[3] Univ N Carolina, Gillings Sch Global Publ Hlth, Dept Maternal & Child Hlth, Chapel Hill, NC USA
[4] Univ N Carolina, Sch Social Work, Chapel Hill, NC USA
[5] Univ N Carolina, Gillings Sch Global Publ Hlth, Dept Hlth Behav, Chapel Hill, NC USA
[6] Univ N Carolina, Gillings Sch Global Publ Hlth, Dept Nutr, Chapel Hill, NC USA
[7] Univ N Carolina, Ctr Hlth Promot & Dis Prevent, Chapel Hill, NC USA
[8] Univ N Carolina, Sch Med, Dept Social Med, Chapel Hill, NC USA
[9] 317 Rosenau Hall,CB 7440, Chapel Hill, NC 27599 USA