1. Center for Population Health, Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
2. Department of Rehabilitation Medicine, Faculty of Medicine Building, University of Malaya, 50603 Kuala Lumpur, Malaysia
3. SEACO/School of Medicine and Health Sciences, Monash University Malaysia, 146 Jalan Sia Her Yam, Segamat District, 85000 Jahor State, Malaysia