1. Department of Pediatrics, the Chinese University of Hong Kong, the Prince of Wales Hospital, Shatin, Hong Kong
2. Department of Medicine & Therapeutics, the Chinese University of Hong Kong, the Prince of Wales Hospital, Shatin, Hong Kong
3. Department of Physical Education, Hong Kong Baptist University, Kowloon, Hong Kong
4. Centre for Clinical Trials and Epidemiological Research, the Chinese University of Hong Kong, the Prince of Wales Hospita, Shatin, Hong Kong