Associations of Caffeinated Beverage Consumption and Screen Time with Excessive Daytime Sleepiness in Korean High School Students

The present study investigated caffeinated beverage consumption and screen time in the association with excessive daytime sleepiness (EDS) and sleep duration. We conducted a cross-sectional study including 249 Korean male high school students. These participants responded to a questionnaire inquiring the information on lifestyle factors, consumption of caffeinated beverages, time spent for screen media, and sleep duration as well as to the Epworth Sleepiness Scale (ESS) questionnaire. EDS was defined as ESS scores of 9 or greater. Students with EDS consumed greater amount of chocolate/cocoa drinks and spent longer time for a TV and a mobile phone than those without EDS (p 8 hours) consumed greater amount of chocolate/cocoa drinks than others (p < 0.05). Screen time did not differ according to the categories of sleep duration. Although these findings do not support causal relationships, they suggest that screen time is associated with EDS, but not with sleep duration, and that consumption of certain types of caffeinated beverages is associated with EDS and sleep duration. Adolescents may need to reduce screen time and caffeine consumption to improve sleep quality and avoid daytime sleepiness.

Associations between dietary patterns and screen time among Korean adolescents

Data are limited on the association between dietary patterns and screen time among Korean adolescents. The present study identified dietary patterns of 691 adolescents, aged 13-18 years, who had participated in the Third Korean National Health and Nutrition Examination Survey (KNHANES III) and analyzed their associations with screen time. Screen time was defined as the time spent watching TV, using a computer, or playing video games was calculated as a sum of all these times. Dietary patterns and their factor scores were derived from a food frequency questionnaire using the factor analysis method. To analyze the association between dietary patterns and screen time, we conducted multiple linear regression analysis. We also performed multiple logistic regression analysis to estimate odds ratios (OR) of excessive screen time (2 hours or longer per day) and 95% confidence intervals (CI). We identified 2 dietary patterns labeled "the Korean healthy dietary pattern" and "the Western diet and fast foods pattern". The former included mixed grains, legumes, potatoes, red meat, eggs, fish, dairy products, fruits, vegetables, seaweeds, and mushrooms, whereas the latter included noodles, bread, red meat, poultry, fast foods, snack, and soft drinks. After controlling for potential confounding factors, factor scores for the Korean healthy dietary pattern were inversely associated (P-value for trend < 0.01) and those for the Western diet and fast foods pattern were positively associated with the screen time (P-value for trend < 0.01). Adolescents in the top tertile of the scores for the Korean healthy dietary pattern had a multivariable-adjusted OR [95% CI] of 0.44 (0.25-0.75) for excessive screen time compared with those in the lowest tertile. On the basis of these findings, adolescents who have excessive screen time may need to be encouraged to consume a more healthy diet.