The Relationship Between Caffeine, Sleep, and Behavior in Children

Abstract

Study objectives: To examine caffeine consumption from various dietary sources in a cohort of Australian children and the relationship between caffeine consumption, sleep, and daytime behavior.

Methods: Children aged 8 to 12 years and their parents/guardians completed a battery of questionnaires. Children completed a caffeine questionnaire while parents completed questionnaires regarding demographics, sleep, and behavior.

Results: The final sample consisted of 309 children (mean ± standard deviation [SD] age 10.6 ± 1.3 years, male = 48%) and corresponding parent reports. On average a mean ± SD 10.2 ± 17.4 mg/day of caffeine was consumed with a range of zero to 151 mg/day. Of the children who consumed caffeine (87% of the sample), the largest contributor was coffee and tea; making up 41% of total caffeine intake, and sodas (soft drinks) contributed to 40% of caffeine intake. Total caffeine consumption was significantly associated with sleep routine (r = 0.152); morning tiredness (r = 0.129); restless sleep (r = 0.113); and internalizing behavioral problems (r = 0.128). Using path analysis, caffeine consumption was positively associated with morning tiredness (β = 0.111, P = .050) which was positively associated with internalizing behaviors (β = 0.432, P < .001). The addition of sleep routine and restless sleep to the model led to a complete mediation of caffeine consumption on morning tiredness, as well as a partial mediation of the association between morning tiredness and internal behaviors.

Conclusions: In 8- to 12-year-olds the primary sources of caffeine are coffee/tea and sodas. Overall mean caffeine consumption is small by adult standards but has an effect on behavior and sleep in children. The effect on behavior is mediated by disrupted sleep, indicating that caffeine is a contributor to sleep problems and related behavior in children.

Keywords: behavior; caffeine; internalizing behaviors; morning tiredness; path analysis; restless sleep; school-aged children; sleep; sleep routine.

Figure 1. Description of recruitment strategies and participant flow from each source.

Figure 2. Initial model.

Direct pathway analysis with beta (β) values between the controlled variables (age and socioeconomic status) and between total caffeine consumption, morning tiredness, and internalizing behaviors. * = P < .05. ** = P < .01. *** = P < .001.

Figure 3. Final model.

Indirect pathway analysis with beta (β) values between the controlled variables (age and socioeconomic status) and between total caffeine consumption, sleep routine, restless sleep, morning tiredness and internalizing behaviors. A straight arrow represents a hypothesized effect. * = P < .05. ** = P < .01. *** = P < .001.