Papua New Guinea Institute of Medical Research - Population Health and Demography Unit, Papua New Guinea Institute of Medical Research, Papua New Guinea Institute of Medical Research, Papua New Guinea Institute of Medical Research - Population Health and Demography Unit, Papua New Guinea Institute of Medical Research - Population Health and Demography Unit, Papua New Guinea Institute of Medical Research - Population Health and Demography Unit, University of Wollongong and Papua New Guinea Institute of Medical Research - Population Health and Demography Unit