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Volume 15 No. 10
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Accepted Papers

Scientific Investigations

Ten-Year Secular Trends in Sleep/Wake Patterns in Shanghai and Hong Kong School-Aged Children: A Tale of Two Cities

Guanghai Wang, PhD1,2,*; Jihui Zhang, MD, PhD3,*; Siu Ping Lam, MRCPsych, FHKAM (Psych)3; Shirley Xin Li, PhD, DClinPsy, RPSGT4,5; Yanrui Jiang, MD1,2; Wanqi Sun, PhD1,2,4,6; Ngan Yin Chan, MSc, Mphil3,4; Alice Pik Shan Kong, FRCP7; Yunting Zhang, MD1,2; Shenghui Li, MD8; Albert Martin Li, FHKCPaed, MD9; Fan Jiang, MD1,2; Xiaoming Shen, MD1,2; Yun Kwok Wing, FRCPsych3
1Department of Developmental and Behavioral Pediatrics, Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; 2MOE-Shanghai Key Laboratory of Children’s Environmental Health, Shanghai, China; 3Department of Psychiatry, Sleep Assessment Unit, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; 4Department of Psychology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; 5The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China; 6Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; 7Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; 8Shanghai Jiao Tong University School of Public Health, Shanghai, China; 9Department of Pediatrics, Faculty of Medicine, The Chinese University of Hong Kong, N.T., Hong Kong SAR, China; *Co-first author, contributed equally

Study Objectives:

To compare the secular trends of sleep/wake patterns in school-aged children in Hong Kong and Shanghai, two major metropolitan cities in China with two different policies that school start time was delayed in Shanghai, but advanced in Hong Kong in 10 years’ time.


Participants were from two waves of cross-sectional school-based surveys of children aged 6 to 11 years. In Shanghai, 4,339 and 13,795 children participated in the 2005 and 2014 surveys, respectively. In Hong Kong, 6,231 and 4,585 children participated in the 2003 and 2012 surveys, respectively. Parents reported their children’s bedtime and wakeup time, and thus sleep duration, short sleep (≤ 9 hours) and weekend oversleep (difference in sleep duration between weekday and weekend > 2 hours) were determined.


Hong Kong children had later bedtime and wakeup time and slept consistently less than their Shanghai counterparts at both survey time points. The shorter sleep duration was particularly marked during weekdays. Over the interval period, weekday sleep duration significantly decreased from 9.2 to 8.9 hours as wakeup time became earlier for Hong Kong children, but increased from 9.4 to 9.6 hours as wakeup time became later for children in Shanghai. Children from both cities slept longer on the weekends. Prevalence of weekend oversleep significantly increased in Hong Kong children, but no interval change was found in Shanghai children.


The findings indicate subcultural differences in sleep/wake patterns in Shanghai and Hong Kong school-aged children. In particular, sleep duration had increased for Shanghai children, but decreased for Hong Kong children over 10 years. The benefits and barriers of delaying school start time for optimizing sleep health in school-aged children should be further explored.


Wang G, Zhang J, Lam SP, Li SX, Jiang Y, Sun W, Chan NY, Kong APS, Zhang Y, Li S, Li AM, Jiang F, Shen X, Wing YK. Ten-year secular trends in sleep/wake patterns in Shanghai and Hong Kong school-aged children: a tale of two cities. J Clin Sleep Med. 2019;15(10):1495–1502.

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