H Litwin1, D J H Deeg2, H-W Wahl3. 1. Paul Baerwald School of Social Work & Social Welfare, Israel Gerontological Data Center, The Hebrew University in Jerusalem, Mount Scopus, 91905 Jerusalem, Israel. 2. Department of Epidemiology and Biostatistics/LASA, VU University Medical Centre, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands. 3. Department of Psychological Aging Research, Heidelberg University, Institute of Psychology, Bergheimer Strasse 20, 69115 Heidelberg, Germany.