[1] Univ London Imperial Coll Sci Technol & Med, Sch Publ Hlth, Dept Epidemiol & Biostat, MRC HPA Ctr Environm & Hlth, London W2 1PG, England
[2] Harvard Univ, Sch Publ Hlth, Dept Epidemiol, Boston, MA 02115 USA
[3] Harvard Univ, Sch Publ Hlth, Dept Biostat, Boston, MA 02115 USA
[4] Harvard Univ, Sch Publ Hlth, Dept Global Hlth & Populat, Boston, MA 02115 USA
[5] Harvard Univ, Sch Publ Hlth, Dept Environm Hlth, Boston, MA 02115 USA
[6] Univ Calif Berkeley, Dept Stat, Berkeley, CA 94720 USA
[7] WHO, Dept Chron Dis & Hlth Promot, CH-1211 Geneva, Switzerland
[8] WHO, Dept Hlth Stat & Informat, CH-1211 Geneva, Switzerland
[9] Univ Washington, Inst Hlth Metr & Evaluat, Seattle, WA 98195 USA