Relationships among Sleep Time, Physical Activity Time, Screen Time, and Nutrition Literacy of Adolescents: A Cross-Sectional Study in Chongqing, China.

Background: Unhealthy lifestyles among adolescents are reaching alarming levels and have become a major public health problem. This study aimed to assess the relationship between sleep time, physical activity (PA) time, screen time (ST), and nutritional literacy (NL). Methods: This cross-sectional online study involving adolescents aged 10-18 years was conducted in September 2020 in 239 schools in Chongqing, China. NL was measured using the "Nutrition Literacy Scale for middle school students in Chongqing (CM-NLS)". According to the recommended by the Chinese dietary guidelines (2022), we divided the sleep time of junior high school students into <9 h and ≥9 h, high school students into <8 h and ≥8 h, divided the workdays into weekend PA time < 1 h and ≥1 h, and divided the workdays into weekend ST < 2 h and ≥2 h. The multinomial logistic regression model was used to examine the association. Results: A total of 18,660 adolescents (50.2% males) were included. The proportion of participants that were junior high school students and attended boarding schools was 57.2% and 65.3%, respectively. Compared with senior high school students, junior high school students had a higher level of NL. Whether on workdays or weekends, participants with sleep time ≥ 8/9 h, PA time ≥ 1 h, and ST < 2 h per day had higher levels of NL. On weekdays, participants who met the sleep time ≥ 8 h/9 h (OR = 1.48, 95% CI: 1.36, 1.62) and PA time ≥ 1 h (OR = 1.69, 95% CI: 1.59, 1.81) had higher reporting of NL levels. Conclusions: Sleep time, PA time, and ST were positively correlated with NL among adolescents, especially junior high school students.