An epidemiologic study of sleep problems among adolescents in North Taiwan

To investigate the prevalence of sleep problems and their association with daytime sleepiness among Taiwanese adolescents by use of a validated questionnaire.

This is a cross-sectional, community based study with self-reported sleep questionnaires. Completed questionnaires from 1939 adolescent subjects from schools in Lin-Kou district (Taipei, Taiwan) (96.7% responded); 1906 valid questionnaires (62.3% girls) were analyzed. The randomly selected classes included elementary grade 6 (age range: 12-13 years), junior high school (age range: 14-16 years) and senior high school students (age range: 17-18 years).

The mean sleep duration on weekdays was 7.35±1.23 h and on weekends 9.38±1.62 h. Weeknight sleep decreased significantly with increasing school grade (6.87±1.14 h for high school seniors). There was a trend towards increased daytime sleepiness for students in higher school grade levels. Daytime sleepiness directly correlated with shorter total sleep time (TST) on weekdays, longer TST on weekends, snoring, insomnia and nightmares. Coffee intake, smoking, periodic leg movement/restless legs syndrome, body mass index (BMI), mouth breathing and breathing problems were indirect factors that induced daytime sleepiness. Pearson correlation showed no significant correlation between the TST during the weekday and BMI (-0.047, p=0.079) or body weight (BW) (-0.048, p=0.072). But it showed significant negative correlation (-0.103, p=0.0001) for increasing total sleep time on the weekend and decreasing BMI.

Daytime sleepiness correlated with the shorter TST on weekdays, longer TST on weekends, snoring, insomnia and nightmares. There is no significant correlation between the weekday TST and BMI or BW. Meals and food intake of children are still traditional and have not changed as much in Taiwan as in some other western countries, and compared to a similar survey performed 12 years ago in Taiwan among junior high school students, sleep duration was not significantly different but reduced due to school demands.