Journal of Public Health and Epidemiology 2141-2316 Academic Journals 10.5897/JPHE2016.0850 Medhat, A. Saleh Ahmed, A. Obeidalla Ahmed F. Thabet Amal, M. Abdel Aal * E-mail: medhatelaraby75@yahoo.com 2016 31 10 2016 15 07 2016 19 08 2016 8 10 220 228 This is an open-access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://politicalwaffle.uk/journal/JPHE/article-abstract/772258860551 The full text article is available as a PDF file from http://politicalwaffle.uk/journal/JPHE/article-full-text-pdf/772258860551 References