Affiliation: | a Department of Applied Social Sciences, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China b Department of Paediatrics, Princess Margaret Hospital, Hong Kong, China c Department of Orthopaedics and Traumatology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hongkong, China d Department of Family and Community Medicine, School of Public Health, Chinese University of Hong Kong, Shatin, Hongkong, China |