1. Department of Family Medicine and Public Health, Sultan Qaboos University Hospital, Sultan Qaboos University, Muscat 123, Oman
2. Department of Primary Health Care, Ministry of Health, Muscat 100, Oman
3. Ministry of Health, Muscat 100, Oman
4. Department of Family Medicine and Public Health, Sultan Qaboos University, Muscat 123, Oman