[1] Univ Massachusetts, Sch Publ Hlth & Hlth Sci, Amherst, MA 01003 USA
[2] Univ S Carolina, Dept Environm Hlth Sci, Columbia, SC 29208 USA
[3] Univ S Carolina, Dept Epidemiol & Biostat, Columbia, SC 29208 USA
[4] Med Univ S Carolina, Dept Biostat Bioinformat & Epidemiol, Charleston, SC 29401 USA
[5] Univ S Carolina, Dept Family & Prevent Med, Columbia, SC 29203 USA