[1] Yale Univ, Sch Med, Dept Epidemiol & Publ Hlth, New Haven, CT 06520 USA
[2] Harvard Univ, Brigham & Womens Hosp, Sch Med, Div Aging, Boston, MA 02115 USA
[3] Vet Adm Boston Healthcare Syst, Massachusetts Vet Epidemiol Res & Informat Ctr, Boston, MA USA
[4] Yale Univ, Sch Med, Yale Child Hlth Res Ctr, Dept Pediat, New Haven, CT 06520 USA
[5] Yale Univ, Sch Med, Yale Child Hlth Res Ctr, Dept Genet, New Haven, CT 06520 USA
[6] Yale Univ, Sch Med, Yale Child Hlth Res Ctr, Dept Investigat Med, New Haven, CT 06520 USA
[7] Brock Univ, Dept Child & Youth Studies, St Catharines, ON L2S 3A1, Canada
[8] Brock Univ, Dept Psychol, St Catharines, ON L2S 3A1, Canada
[9] Univ Bristol, Sch Social & Community Med, Bristol, Avon, England