1. School of Graduate Studies University of Hargeisa , Pepsi Road, Ahmed Dhagah District, Hargeisa, Somaliland
2. Department of Community Medicine and Global Health, Institute of Health and Society, University of Oslo , Post Box 1130 Blindern, 0318 Oslo , Norway
3. Department of Community Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway , 9037, Tromsø , Norway
4. Department of Epidemiology, Faculty of Medicine, Prince of Songkla University , Hat Yai, Songkhla 90110 , Thailand