[1] Harvard Univ, Sch Publ Hlth, Dept Soc Human Dev & Hlth, Boston, MA 02115 USA
[2] Dana Farber Canc Inst, Ctr Community Based Res, Boston, MA 02115 USA
[3] Northwestern Univ, Feiberg Sch Med, Dept Prevent Med, Chicago, IL 60611 USA
[4] Univ Massachusetts, Dept Publ Hlth Biostat & Epidemiol Concentrat, Amherst, MA 01003 USA