[1] INSERM, Dept Epidemiol Demog & Social Sci, U822, F-94276 Le Kremlin Bicetre, France
[2] Univ Massachusetts, Sch Med, Worcester, MA USA
[3] Princeton Univ, Off Populat Res, Princeton, NJ 08544 USA
[4] Hull York Med Sch, Kingston Upon Hull, N Humberside, England
[5] Univ Paris Sud, Fac Med, F-94275 Le Kremlin Bicetre, France
[6] Natl Inst Demog Studies, INED, Paris, France