Social jet lag, chronotype and body mass index in 14–17-year-old adolescents

Abstract

The relationship between sleep duration and obesity in adolescents is inconclusive. This may stem from a more complex relationship between sleep and obesity than previously considered. Shifts towards evening preferences, later sleep-wake times, and irregular sleep-wake patterns are typical during adolescence but their relationship to body mass index has been relatively unexplored. This cross sectional study examined associations between sleep duration, midpoint of sleep, and social jetlag (estimated from seven days of continuous actigraphy monitoring) and morningness/eveningness with body mass indexes (BMI z scores) and waist to height ratios in 14 to 17 year old adolescents. Seventy participants were recruited from 9th and 10th grades at a public high school. Participant characteristics were as follows: 74% female, 75% post-pubertal, 36% Hispanic, 38% White, 22% Black, 4% Asian, and 64% free/reduced lunch participants with a mean age of 15.5 (SD, 0.7). Forty one percent of the participants were obese (BMI ≥ 95th percentile); 54% were abdominally obese (waist to height ratio ≥ 0.5). Multivariable general linear models were used to estimate the association between the independent variables (school night sleep duration, free night sleep duration, midpoint of sleep (corrected), social jetlag, and morningness/eveningness) and the dependent variables (BMI z scores and waist to height ratios). Social jetlag positively associated with BMI z scores (p < 0.01) and waist to height ratios (p = 0.01). Midpoint of sleep (corrected) positively associated with waist to height ratios (p = 0.01). After adjusting for social jetlag, school night sleep duration was not associated with waist to height ratios or BMI z scores. Morningness/eveningness did not moderate the association between sleep duration and BMI z scores. Findings from this study suggest that chronobiological approaches to preventing and treating obesity may be important for accelerating progress in reducing obesity rates in adolescents.

Chronotype and Social Jetlag - a (self-)critical review

“…There are several behavioral outcomes associated with SJL: less healthy dietary patterns [68], higher probability of being a smoker [3], worse academic performance in high school and university [30,69] and higher physical and verbal aggression in undergraduate students [70]. There is also a great amount of evidence for an association between SJL and risk for metabolic disorders and/or being obese [67,[71][72][73][74][75][76]. Depressive symptoms also seem to be associated with SJL [57,77,78], although such link has not been found with minor or sub-syndromal psychiatric symptoms [79,80], depressive symptoms in young students living in a rural area in Brazil [81] or in healthy controls vs. a clinical sample [82].…”

Potential circadian and circannual rhythm contributions to the obesity epidemic in elementary school age children

“…For example, shift work is associated with an increased risk for obesity, type 2 diabetes, metabolic syndrome, and cardiovascular disease in adults, especially long-term shift workers [37][38][39][40][41]. Social jet lag has also been associated with obesity in adults [42] as well as adolescents and children [42][43][44][45]. Night Eating Syndrome, an eating disorder that involves eating 25% or more of one's daily calories after the evening meal, was associated with increased risk of obesity and changes in the timing and amplitude of metabolic hormones such as glucose, insulin, ghrelin, and leptin in adults [14,46,47].…”

Sleep timing is associated with self-reported dietary patterns in 9- to 15-year-olds

“…Late bedtimes and/or a delayed sleep phase pattern in childhood and adolescence are associated with adiposity and weight status, even after controlling for sleep duration and a number of demographic and health factors. 15,26–28 Furthermore, youth self-reporting late sleep timing (bedtimes and wake times) are more likely to have higher BMI z scores and to consume more energy-dense, nutrient-poor food, whereas those reporting early sleep timing are more likely to eat more fruits and vegetables. 14 Later bedtimes and wake times in adolescence are also associated with the tendency to consume caffeinated drinks, eat more fast food and fewer dairy products, and show increased food preoccupation.…”