Background
Methods
Protocol and registration
Eligibility criteria
Population
Intervention (exposure)
Comparison
Outcomes (health indicators)
Study designs
Information sources and search strategy
Study selection
Data extraction
Risk of bias and study quality assessment
Synthesis of results
Results
Description of studies
Data synthesis
Adiposity
No of studies | Design | Quality Assessment | No of participants | Absolute effect | Quality | ||||
---|---|---|---|---|---|---|---|---|---|
Risk of bias | Inconsistency | Indirectness | Imprecision | Other | |||||
Mean age ranged between 0 and 4.9 years. Data were collected cross-sectionally and up to 9.5 years of follow-up. Sleep duration was assessed by actigraphy or parent report. Adiposity was assessed objectively as body weight, body mass index (absolute, z-score or percentile), waist-for-length ratio, weight status (different definitions for underweight, normal weight, overweight, obese) or % body fat/fat mass/fat mass index (bioelectrical impedance, dual-energy X-ray absorptiometry, skinfolds). | |||||||||
13 | Longitudinal studya
| No serious risk of bias | No serious inconsistency | No serious indirectness | No serious imprecision | None | 31,482 | LOW | |
18 | Cross-sectional studyb
| No serious risk of bias | No serious inconsistency | No serious indirectness | No serious imprecision | None | 30,829 | LOW |
Emotional regulation
No of studies | Design | Quality Assessment | No of participants | Absolute effect | Quality | ||||
---|---|---|---|---|---|---|---|---|---|
Risk of bias | Inconsistency | Indirectness | Imprecision | Other | |||||
Mean age ranged between 1 month and 4.7 years. Intervention studies were between 1 day and 25 days (in-home protocol), and longitudinal studies were up to 6 years. Sleep duration was assessed by actigraphy, polysomnography or parent report. Emotional regulation was assessed through various instruments (e.g. video-recording, cortisol response, or questionnaires). | |||||||||
2 | Randomized triala
| No serious risk of bias | No serious inconsistency | No serious indirectness | No serious imprecision | None | 22 | Nap deprivation resulted in moderate-to-large effects on self-regulation strategies, with decreases in skepticism (d = 0.77; 7% change), negative self-appraisal (d = 0.92; 5% change) and increases in physical self-soothing (d = 0.68; 10% change), focus on the puzzle piece that would not fit (perseveration; d = 0.50; 9% change) and insistence on completing the unsolvable puzzle (d = 0.91; 10% change). After losing daytime sleep, toddlers were less able to engage effectively in a difficult task and reverted to less mature self-regulation strategies than when they were well rested [42]. When sleep restricted, children displayed less confusion in response to neutral pictures, more negativity to neutral and negative pictures, and less positivity to positive pictures. Sleep restriction also resulted in a 34% reduction in positive emotion responses (solvable puzzle), as well as a 31% increase in negative emotion responses and a 39% decrease in confused responses (unsolvable puzzle) [43]. | HIGH |
1 | Non-randomized trialb
| No serious risk of bias | No serious inconsistency | No serious indirectness | Serious imprecisionc
| None | 7 | The cortisol awakening response was robust after nighttime sleep, diminished after sleep restriction, and smaller but distinct after morning and afternoon (not evening) naps. Cortisol remained elevated 45 min after morning and afternoon naps [44]. | VERY LOW |
5 | Longitudinal studyd
| No serious risk of bias | No serious inconsistency | No serious indirectness | No serious imprecision | None | 46,959 | LOW | |
17 | Cross-sectional studye
| No serious risk of bias | Serious inconsistencyf
| No serious indirectness | No serious imprecision | None | 16,536 | VERY LOW |
Cognitive development
No of studies | Design | Quality Assessment | No of participants | Absolute effect | Quality | ||||
---|---|---|---|---|---|---|---|---|---|
Risk of bias | Inconsistency | Indirectness | Imprecision | Other | |||||
Mean age ranged between 6 months and 4.9 years. Data were collected cross-sectionally and up to 3 years of follow-up. Sleep duration was assessed by actigraphy or parent report. Cognition was measured by various instruments including memory tasks, imitation tasks, neuropsychological tests, interviews, scales of intelligence or questionnaires. | |||||||||
1 | Randomized triala
| No serious risk of bias | No serious inconsistency | No serious indirectness | No serious imprecision | None | 23 | The number of correct answers in an explicit recognition task was significantly higher in the nap (control) compared to the wake (sleep-restricted) condition, whereas implicit memory (priming task) did not differ between conditions [65]. | HIGH |
4 | Longitudinal studyb
| No serious risk of bias | No serious inconsistency | No serious indirectness | No serious imprecision | None | 438 | Children getting higher proportions of their sleep at night as infants (i.e. 1 year) were found to perform better on executive functions, but did not show better general cognition [66]. Higher proportions of total sleep occurring at night time, at both 12 and 18 months, were associated with better performance on executive tasks, especially those involving a strong impulse control component. However, the total sleep duration at 12 and 18 months was not associated with executive functioning at 18 and 26 months. Sleep duration at 12 months was not correlated with 18 month working memory (r = −0.11, p > 0.05), 26 month conflict executive functioning (r = −0.10, p > 0.05) or 26 month impulse control (r = −0.06, p > 0.05). Sleep duration at 18 months was not correlated with 18 month working memory (r = −0.16, p > 0.05), 26 month conflict executive functioning (r = 0.09, p > 0.05) or 26 month impulse control (r = −0.16, p > 0.05) [67]. The number of daytimenaps was positively associated with both predicted expressive (p = 0.062) and receptive vocabulary growth (p = 0.006), whereas the length of nighttime sleep was negatively associated with rate of predicted expressive vocabulary growth (p = 0.045) [68]. Children who had 8 h or more of sleep had significantly higher General Conceptual Ability (GCA) scores than those with 7 h or less of sleep by 35.53 points at age 3. Children with more than 10 h of sleep had higher GCA scores at age 3 compared to children with 8–9 h or less of sleep (233.91 vs. 203.92, respectively) [69]. | LOW |
11 | Cross-sectional studyc
| No serious risk of bias | No serious inconsistency | No serious indirectness | No serious imprecision | None | 10,838 | LOW |
Motor development
No of studies | Design | Quality Assessment | No of participants | Absolute effect | Quality | ||||
---|---|---|---|---|---|---|---|---|---|
Risk of bias | Inconsistency | Indirectness | Imprecision | Other | |||||
Mean age ranged between 7.4 months and 13 months. Data were collected cross-sectionally only. Sleep duration was assessed by actigraphy or parent report. Motor development was assessed using the Ages and Stages Questionnaire in both studies. | |||||||||
2 | Cross-sectional studya
| No serious risk of bias | No serious inconsistency | No serious indirectness | No serious imprecision | None | 1403 | LOW |
Growth
No of studies | Design | Quality Assessment | No of participants | Absolute effect | Quality | ||||
---|---|---|---|---|---|---|---|---|---|
Risk of bias | Inconsistency | Indirectness | Imprecision | Other | |||||
Mean age ranged between 4 months and 17 months. Data were collected cross-sectionally and up to 13 months. Sleep duration was assessed by actigraphy or parent report. Growth was assessed using the maximum stretch technique and using weight above the expected weight for length. | |||||||||
1 | Longitudinal studya
| Serious risk of biasb
| No serious inconsistency | No serious indirectness | No serious imprecision | None | 23 | Saltatory length growth was associated with increased total daily sleep hours (p < 0.001) and number of sleep bouts (p = 0.001). Subject-specific probabilities of a growth saltation associated with sleep included a mean odds ratio of 1.20 for each additional hour of sleep (n = 8, 95% CI 1.15–1.29) and 1.43 for each additional sleep bout (n = 12, 95% CI 1.21–2.03) [29]. | VERY LOW |
1 | Cross-sectional studyc
| No serious risk of bias | No serious inconsistency | No serious indirectness | Serious imprecisiond
| None | 139,305 | Using actigraphy, sleep duration was associated with weight-to-length ratio (r = −0.47, p < 0.01) in girls only. Using the questionnaire, night sleep duration was associated with weight-to-length ratio (r = −0.26, p < 0.05) and weight above the expected weight for length (r = −0.25, p < 0.05) in the total sample [77]. | VERY LOW |
Cardiometabolic health
Sedentary behaviour
No of studies | Design | Quality Assessment | No of participants | Absolute effect | Quality | ||||
---|---|---|---|---|---|---|---|---|---|
Risk of bias | Inconsistency | Indirectness | Imprecision | Other | |||||
Mean age ranged between 6 months and 4.5 years. Data were collected cross-sectionally and up to 4 years. Sleep duration was assessed by parent report. Sedentary behaviors (screen time) were assessed using time-use diaries or questionnaires. | |||||||||
1 | Longitudinal studya
| Serious risk of biasb
| No serious inconsistency | No serious indirectness | No serious imprecision | None | 2984 | Sleep duration at 4 years of age was inversely associated with television viewing (β = −0.07, p = 0.003) and computer use (β = −0.04, p = 0.001) at 6 years of age [22]. | VERY LOW |
4 | Cross-sectional studyc
| Serious risk of biasd
| No serious inconsistency | No serious indirectness | No serious imprecision | None | 42,751 | Short sleep duration was associated with time spent watching TV (OR: 1.65, 95% CI 1.23–2.21 per additional hour/24 h) in boys. In girls, the association was not significant (p = 0.75) [31]. Infants who were exposed to screen media in the evening at 12 months of age had a 28-min lower nighttime sleep duration on weekdays. Moreover, infants who were exposed to screen media in the evening at age 6 months and 12 months had shorter 12-month nighttime sleep duration compared with those who were not exposed to screen media after 7 pm at both ages [78]. Watching more than an hour of TV in the evening was associated with short sleep duration (OR = 1.89, 95% CI 1.26–2.84). However, the association was not significant with watching more than an hour of TV in the morning (OR = 1.13, 95% CI 0.80–1.58) [79]. Short sleep duration was associated with longer hours spent watching television (OR = 1.91, 95% CI 1.26–2.90 for ≥4 h/day) and playing computer games (OR = 1.62, 95% CI 1.18–2.23 for ≥2 h/day) compared to not watching/playing [80]. | VERY LOW |
Physical activity
No of studies | Design | Quality Assessment | No of participants | Absolute effect | Quality | ||||
---|---|---|---|---|---|---|---|---|---|
Risk of bias | Inconsistency | Indirectness | Imprecision | Other | |||||
Mean age ranged between 20 months and 4.5 years. Data were collected cross-sectionally and up to 4 years. Sleep duration was assessed by parent report. Physical activity was assessed using accelerometers, time-use diaries or questionnaires. | |||||||||
1 | Longitudinal studya
| Serious risk of biasb
| No serious inconsistency | No serious indirectness | No serious imprecision | None | 2984 | Sleep duration at 4 years of age was not associated with physical activity at 6 years of age (β = −0.02, 95% CI −0.09-0.03) [22]. | VERY LOW |
3 | Cross-sectional studyc
| No serious risk of bias | No serious inconsistency | No serious indirectness | No serious imprecision | None | 2272 | Longer nighttime sleep duration was associated with more physical activity (MVPA min/day: r = 0.19, p = 0.012; activity counts: r = 0.21, p = 0.006). In multivariable models, nighttime sleep duration was positively associated with physical activity (β = 0.332, p = 0.017) [30]. Sleep duration was not associated with physical activity in either boys (p = 0.89) or girls (p = 0.41) [31]. Total daily sleep duration was positively associated with physical activity in boys only (OR = 1.04, 95% CI 1.02–1.07) [81]. | LOW |
Quality of life/well-being
No of studies | Design | Quality Assessment | No of participants | Absolute effect | Quality | ||||
---|---|---|---|---|---|---|---|---|---|
Risk of bias | Inconsistency | Indirectness | Imprecision | Other | |||||
Children were 3 years of age and followed until first-year junior high school (approximately 13 years old). Data were collected longitudinally (approximately a 10-year follow-up period). Sleep duration was assessed by parent report. Quality of life was assessed using the Dartmouth Primary Care Cooperative Project (COOP) charts. | |||||||||
1 | Longitudinal studya
| Serious risk of biasb
| No serious inconsistency | No serious indirectness | No serious imprecision | None | 9674 | Short sleep duration at 3 years of age (< 10 h vs. > 11 h) was not associated with quality of life at age ~13 years (OR = 1.15, 95% CI 0.99–1.33, p = 0.06) [82]. | VERY LOW |
Risks/injuries
No of studies | Design | Quality Assessment | No of participants | Absolute effect | Quality | ||||
---|---|---|---|---|---|---|---|---|---|
Risk of bias | Inconsistency | Indirectness | Imprecision | Other | |||||
Mean age ranged between 18 months and 4.9 years. Data were collected cross-sectionally only. Sleep duration was assessed by parent report. Risks/injuries were assessed using medical record data, the Injury Behavior Checklist, interviews, or chart reviews of injuries. | |||||||||
3 | Cross-sectional studya
| No serious risk of bias | No serious inconsistency | No serious indirectness | No serious imprecision | None | 2382 | Children with shorter sleep duration sustained a higher number of medically attended injuries (b = 0.1759, p < 0.05) [83]. Usual sleep duration shorter than 8 h was associated with an increased risk of accidental falls (OR = 2.7, 95% CI 1.2–6.1) [84]. The Children’s Sleep Habits Questionnaire (CSHQ) sleep duration score did not significantly differ between the high injury and low injury groups (5.93 ± 1.03 vs. 6.36 ± 0.96, respectively, p = 0.09). Also, the CSHQ sleep duration score did not significantly differ between the high-injury-behavior and the low-injury-behavior groups (5.73 ± 2.10 vs. 4.32 ± 1.92, respectively, p not provided) after Bonferroni correction. The Pearson correlation coefficient between sleep duration and the total Injury Behavior Checklist score was r = 0.32, p = 0.005. To specifically examine the relationship between parent-reported sleep duration and injuries and injury behavior, they divided the group by median split for sleep duration (low sleep < 690 min, high sleep ≥690 min). There were no significant differences in the number of injuries in the past 2 years or in the Injury Behavior Checklist total score [85]. | LOW |
Summary of findings
Health Indicator | # of studies | Quality of Evidence | Summary of Findings |
---|---|---|---|
Critical | |||
Adiposity | 31 | Low |
N = 20 studies reported a significant association between shorter sleep duration and adiposity.
N = 9 studies reported null findings.
N = 2 studies reported a significant association between longer sleep duration and adiposity. |
Emotional Regulation | 25 | Very Low to High |
N = 13 studies reported a significant association between shorter sleep duration and poorer emotional regulation.
N = 10 studies reported null findings.
N = 2 studies reported a significant association between longer sleep duration and poorer emotional regulation. |
Cognitive Development | 16 | Low to High |
N = 6 studies reported a significant association between shorter sleep duration and poorer cognitive function.
N = 8 reported null findings.
N = 2 study reported a significant association between longer sleep duration and poorer cognitive function. |
Motor Development | 2 | Low |
N = 2 studies reported null findings. |
Growth | 2 | Very Low |
N = 2 studies reported better growth with longer sleep duration. |
Important | |||
Sedentary Behavior | 5 | Very Low |
N = 5 studies reported shorter sleep duration was associated with more screen time. |
Physical Activity | 4 | Low to Very Low |
N = 2 studies reported longer sleep duration was associated with more physical activity.
N = 2 studies reported null findings. |
Risks/Injuries | 3 | Low |
N = 2 studies reported a higher risk of injuries with shorter sleep duration.
N = 1 study reported null findings. |
Quality of Life/Well-Being | 1 | Very Low |
N = 1 study reported null findings. |
Cardio-Metabolic Health | 0 | N/A | N/A |