[1] Ohio State Univ, Div Epidemiol, Coll Publ Hlth, Columbus, OH 43210 USA
[2] Tufts Univ, Sch Med, Boston, MA 02111 USA
[3] Univ Massachusetts, Sch Med, EK Shriver Ctr, Waltham, MA USA
[4] Boston Univ, Coll Hlth & Rehabil Sci, Sargent Coll, Boston, MA 02215 USA