[1] Duke Univ, Dept Populat Hlth Sci, Sch Med, Durham, NC 27710 USA
[2] Duke Univ, Duke Margolis Ctr Hlth Policy, Durham, NC 27710 USA
[3] Duke Univ, Dept Obstet & Gynecol, Div Womens Community & Populat Hlth, Sch Med, Durham, NC USA
[4] Duke Univ, Marcus Ctr Cellular Cures, Med Ctr, Durham, NC USA
[5] Duke Univ, Dept Biostat & Bioinformat, Sch Med, Durham, NC USA
[6] Duke Univ, Clin Res Inst, Sch Med, Durham, NC 27710 USA