Sleep and academic performance in Hong Kong adolescents.
BACKGROUND
Sleep problems may have different influences on students' academic performance. We investigated the prevalence of sleep patterns, naps, and sleep disorders, and their associations with academic performance in Hong Kong adolescents.


METHODS
In 2007-2008, 22,678 students aged 12-18 (41.6% boys) completed a questionnaire on sociodemographic characteristics, sleep patterns and problems, and lifestyle factors including exercise, smoking, alcohol drinking, and academic performance.


RESULTS
The prevalence of having >8 hours of sleep was higher on holiday nights (86.4%) than on school-day nights (27.4%). Sleeping after midnight was more common before holidays (49.3%) than before school days (19.9%). Symptoms of insomnia and obstructive sleep apnea (OSA) were reported by 21.5% and 34.4% of students. Having >2 hours of weekend sleep delay was associated with poor academic performance with an odds ratio (OR) (95% confidence interval) of 1.46 (1.29-1.65). However, having 1-2 hours and >2 hours of weekend wake-up delay were both associated with less likelihood of poor academic performance with ORs of 0.64 (0.56-0.73) and 0.69 (0.59-0.80). Other factors associated with poor academic performance included >2 hours of sleep debt, OR of 1.17 (1.03-1.33); having any insomnia symptoms in the past 30 days, OR of 1.27 (1.17-1.37); and having any OSA symptoms at least weekly, OR of 1.23 (1.14-1.32). Napping in the past 5 school days was only marginally associated with poor school performance with an OR of 1.08 (1.00-1.16).


CONCLUSIONS
Poorer academic performance was associated with sleep debt, and symptoms of insomnia and OSA. Sleep compensation but not naps may be a protective factor of poor academic performance.
Department of Community Medicine and School of Public Health, Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong. kkmak@graduate.hku.hk
Kwok-Kei
KK
Mak
So-Lun
SL
Lee
Sai-Yin
SY
Ho
Wing-Sze
WS
Lo
Tai-Hing
TH
Lam
D000293:Adolescent; D002648:Child; D016001:Confidence Intervals; D004522:Educational Status; D005260:Female; D006305:Health Status Indicators; D006723:Hong Kong; D006801:Humans; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D015995:Prevalence; D012572:School Health Services; D020181:Sleep Apnea, Obstructive / Q000473:pathology / Q000523:psychology*; D007319:Sleep Initiation and Maintenance Disorders / Q000473:pathology / Q000523:psychology*; D011795:Surveys and Questionnaires; D013647:Task Performance and Analysis