1. Center for Demography and Health of Aging, University of Wisconsin-Madison, Madison, WI 53706, USA
2. Instituto de Economía, Geografía y Demografía (IEGD), Consejo Superior de Investigaciones Científicas (CSIC) , Madrid, Madrid 28006 , Spain
3. Fielding School of Public Health and California Center for Population Research, UCLA, CA 90095, USA