1. Division of Social Science Program on Social Research and Public Policy, New York University - Abu Dhabi, P.O. Box 129188 Abu Dhabi, United Arab Emirates
2. Department of Population, Family and Reproductive Health, Bloomberg School of Public Health, Johns Hopkins University, 615 N. Wolfe Street, Baltimore, MD 21205, USA
3. Department of Sociology, The Ohio State University, Columbus, OH, USA
4. Bandim Health Project, Bissau, Guinea-Bissau
5. University of Southern Denmark, Odense, Denmark