Table 2.

Longitudinal Studies of Sleep and Obesity

First Author	Sample	Study Design	Sleep Measures	Obesity Measures	Covariates	Results
El-Sheikh⁶³	273 children, mean age of 9.4 yrs at Time 1	longitudinal, Time 1: 2009/2010, Time 2: 2010/2011, Tim 3: 2011–2012	sleep-wake problems (School Sleep Habits Survey), actigraphy- assessed sleep duration	BMI	sex, ethnicity, puberty, income-to- need ratio, asthma, medication use	↑ sleep problems at Time 1 = ↑ BMI at Time 3 in girls. ↓ sleep duration at Time 1 = ↑ BMI at Time 3 in boys and girls, and ↑increase in BMI in girls.
Scharf⁶⁶	10,700 4–5 yr olds in Early Childhood Longitudinal Study-Birth Cohort (N=7000 at age 5)	longitudinal, measures assessed at ages 4 and 5	parent-reported weeknight sleep duration, based on bedtime and waketime	BMI z-score	sex, race/ethnicity, SES, TV viewing	↓ sleep duration at age 4 =↑ BMI increase by age 5. Later bedtime at age 4 = ↑ BMI increase by age 5.
Taveras⁶⁹	1046 children in Project Viva, 6 months old at baseline	longitudinal, yearly assessments from infancy until 7 years	sleep duration score, based on parent reports at each yearly assessment vs. published norms for sleep duration	BMI z-score, total fat mass index, trunk fat mass index, skinfold thickness, waist and hip circumference at age 7	age, gender, race/ethnicity, maternal age, maternal BMI, maternal education, maternal parity, household income, TV viewing time	lowest sleep duration group = ↑ BMI, total and trunk fat mass index, skinfold thickness, waist and hip circumference at age 7 vs. reference group sleep duration after age 2 = NS with BMI at age 7
Chang⁷³	6220 children in 5^th grade at baseline, in the Early Childhood Longitudinal Study- Kindergarten Cohort	longitudinal, children followed from 5th through 8^th grade	sleep duration derived from parent-reported bedtime and official school start time	3 BMI groups: healthy weight (<85th % for age, gender), overweight (≥ 85th% - <95th %) or obese (≥95^th %)	gender, age, parental health, child health, race/ethnicity, parent education, family structure, poverty level	“obese” in 5^th grade ↑ sleep duration predicted moving into “overweight” or “healthy” category by 8^th grade (vs. staying in obese category) “healthy weight” in 5^th grade ↑ sleep duration predicted moving into “overweight” or “obese” category by 8^th grade (vs. staying in healthy category)
Magee⁷⁵	1079 children 4–5 yrs at Wave 1 in the Longitudinal Study of Australian Children	longitudinal, 4 waves of data across 6 yrs	parent-reported diary duration for first 3 waves; self-reported duration at Wave 4	3 BMI groups based on weight at 4 waves: healthy weight (↓ IOTF overweight at all waves), early onset obesity (↑ IOTF at all waves), later onset obesity (↓ IOTF at first wave but ↑ at later waves)	mother and father BMI, mother education, child birth weight	healthy weight trajectory: mixed associations between sleep duration and change in BMI later onset obesity: longitudinal associations NS early onset obesity: ↓ sleep duration at age 6–7 =↑ BMI at age 8–9; ↓ sleep duration at age 8–9 predicted ↑ BMI at age 10–11
Mitchell⁶⁴	1390 adolescents in 9^th grade (Philadelphia suburban high school) at baseline	longitudinal, assessments every 6 months thru 12^th grade	self-reported sleep duration (weighted average for school and weekend night)	self-reported BMI	study wave, gender, race, self-reported physical activity, maternal education, screen time	↓ sleep duration = ↑ increases in BMI from age 14 to 18
Lytle⁷⁷	723 adolescents age 14.7 yrs at baseline	longitudinal, first cohort: baseline, 12 mos, 24 mos second cohort: baseline, 24 mos	self-reported sleep duration averaged across each assessment	BMI, % body fat measured by bioelectrical impedance	grade, race, parent education, school lunch, 24 hr energy intake, depression, pubertal status, physical activity, screen time/sedentary behavior	all longitudinal relationships NS in boys and girls
Araujo⁷⁰	1171 Portuguese adolescents, 13 yrs old at Time 1	longitudinal, 4-year follow-up	self-reported weeknight sleep duration	BMI z-score and body fat % measured by bioelectrical impedance	parental education, Mediterranean Diet Quality Index	boys: ↓ sleep duration at age 13 = ↑ BMI, ↑ body fat % at age 17. girls: ↑ sleep duration at age 13 = ↑ BMI change by age 17 All NS after adjusting for baseline adiposity
O’Dea⁶⁵	939 children in New South Wales, ages 7–12 at baseline	longitudinal, 4 annual assessments starting in 2007	self-reported weeknight sleep duration	BMI	gender, school SES (physical activity not related to BMI and therefore not included as covariate)	univariate analysis: upper tertile of sleep at year 1 = ↓ weight gain and ↓ increase in BMI between years 1 and 4 vs. lower tertile of sleep. multivariate analysis: consistently ↑ sleep = ↓ BMI
Storfer-Isser⁷¹	313 children ages 8–11 at baseline in the Cleveland Children’s Sleep and Health Study	longitudinal, 3 assessments approx 4 yrs apart	parent-reported sleep duration at Times 1 and 2; self-reported sleep duration at Time 3 (weighted mean for weekday/weekend)	BMI z-score	age, race, birth weight, SES	boys: ↓ sleep duration at age 8–11 predicted ↑ BMI at ages 12–15 and 16–19; NS after adjusting for baseline BMI. girls: all NS
Tatone- Takuda⁷²	>1000 Canadian children, approx 2.5 yrs at baseline	longitudinal, annual assessments across 4–5 yrs	parent-reported sleep duration, assessed annually, used to create 3 groups from 2.5 to 6 yrs: 1) short- persistent/increasing 2) 10-hr persistent, 3) 11-hr persistent	BMI at ages 6 and 7	child overweight or obese at 2.5 yrs, mother’s immigrant status, mother overweight or obese, household income, vegetable/fruit consumption	boys: ↑ sleep group, ↓ BMI at age 6 (shortest 2 groups had ↑ BMI than longest group) and at age 7 (shortest group had ↑ BMI than longest group) girls: sleep, BMI NS
Carter⁶²	244 children in New Zealand, age 3 at baseline	longitudinal, assessments every 6 mos from age 3 to age 7	actigraphy-assessed sleep duration	BMI z-score, various adiposity measures from bioelectrical impedence	age, sex, maternal education and income, maternal BMI, birth weight, smoking in pregnancy, ethnicity, behavioral variables assessed at ages 3–5 (diet, activity, TV)	↑ sleep duration at ages 3–5 = 1) ↓ BMI at age 7, 2) ↓ increase in BMI from age 3 to 7, and 3) ↓ risk of overweight at age 7. each hr of sleep = 61% reduction in risk of overweight or obese at age 7
Diethelm⁷⁴	481 German children in the DONALD study	longitudinal, multiple assessments in first 2 yrs after birth; annual assessments from ages 2–7	parent-reported sleep duration at age 1.5 and 2 yrs used to create 3 groups: consistently long, consistently short, inconsistent	BMI, fat mass index, fat free mass index from ages 2 to 7 yrs (mass indices based on skinfold thickness)	sex, birth year, birth weight, rapid weight gain	Inconsistent & consistently short sleepers at age 1.5–2 yrs = ↑ odds of excess body fat at age 7; consistently short sleepers showed progressively higher fat mass index levels until age 7 vs consistently long sleepers. BMI and fat free mass NS between sleep groups
Hiscock⁷⁶	3857 infants (3–18 months) and 3844 preschoolers (4.3– 5.6 yrs) at Wave 1 in the Longitudinal Study of Australian Children	longitudinal, Wave 1: 2004, Wave 2: 2006	parent-reported diary sleep duration	infants: weight-for-age, adjusted for birth length preschoolers: BMI z-score	sex, Wave 1 weight	NS; Sleep duration at Wave 1 did not predict BMI z-score at Wave 2 for either cohort
Seegers⁶⁷	1916 children in Quebec Longitudinal Study of Kindergarten Children, 10 yrs at baseline	longitudinal, annual assessments across 3 yrs	parent-reported weekday sleep duration, assessed annually, used to calculate 3 trajectories: 1) short sleepers, 2) 10.5 hr sleepers, 3) 11 hr sleepers	BMI, based on annual parent reports of height and weight, used to create 3 groups: 1) normal BMI 2) overweight 3) obese	sex, immigrant status, family income, birth weight, parent education, pubertal status (ages 11–13), television and physical activity (age 13)	short sleepers and 10-hr sleepers had ↑ risk of overweight and obese at age 13 versus 11 hr sleepers ↑ sleep duration at age 10 predicted ↓ BMI at age 13
Silva⁶⁸	304 children in the Tucson Children’s Assessment of Sleep Apnea study, 6–12 yrs at baseline	longitudinal, baseline and 5- year follow-up	PSG-assessed TST at baseline and follow- up, used to create 3 groups: 1) ≤ 7.5 hr/night 2) > 7.5 - < 9 hr/night 3) ≥ 9 hr/night daytime sleepiness	BMI z-score at baseline and follow-up	ethnicity, sleep disordered breathing at baseline and follow-up, age	≤ 7.5 hr/night vs. ≥ 9 hr/night at baseline = ↑ odds of obesity at 5-yr follow-up. ≤ 7.5 hr/night vs. ≥ 9 hr/night at baseline = ↑ increase in BMI over 5 yrs daytime sleepiness NS