1. Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur 56000, Malaysia
2. Department of Primary Care Medicine, Faculty of Medicine, Universiti Teknologi MARA Sungai Buloh, Sungai Buloh 47000, Selangor, Malaysia
3. KPJ Tawakkal KL Hospital, Jalan Pahang Barat, Kuala Lumpur 53000, Malaysia
4. Department of Diagnostic & Allied Health Science, Faculty of Health and Life Sciences, Management & Science University, Shah Alam 40100, Selangor, Malaysia
5. Population Health Research Institute (PHRI), Hamilton Health Sciences and McMaster University, Hamilton, ON L8L 2X2, Canada