1. Department of Community Health, Institute of Public Health, Kilimanjaro Christian Medical University College, Moshi, Tanzania
2. Department of Behavioral and Social Sciences, Institute of Public Health, Kilimanjaro Christian Medical University College (KCMUCo), Moshi, Tanzania
3. Department of Epidemiology and Biostatistics, Institute of Public Health, Kilimanjaro Christian Medical University College, Moshi, Tanzania
4. School of Mathematics, Statistics & Computer Science, University of KwaZulu Natal, Pietermaritzburg, South Africa