[1] Univ Minnesota, Sch Publ Hlth, Div Epidemiol & Community Hlth, Minneapolis, MN 55454 USA
[2] Univ Calif San Francisco, San Francisco, CA 94143 USA
[3] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Int Hlth, Baltimore, MD USA
[4] United Nations Populat Fund, New York, NY USA
[5] Int Planned Parenthood Federat, London, England
[6] WHO, CH-1211 Geneva, Switzerland