1. Center for Population Health, Department of Social and Preventive Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
2. Department of Social and Preventive Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
3. Department of Paediatrics, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
4. School of Health and Rehabilitation Sciences, Health Sciences University, Parkwood Campus, Bournemouth, UK