Sleep and Adiposity in Children From 2 to 6 Years of Age

Comparison of actigraphy-measured and parent-reported sleep in association with weight status among preschool children

This study compared weekday and weekend actigraphy-measured and parent-reported sleep in relation to weight status among preschool-aged children. Participants were 3-6 years old preschoolers from the cross-sectional DAGIS-study with sleep data for ≥2 weekday and ≥2 weekend nights. Parents-reported sleep onset and wake-up times were gathered alongside 24 h hip-worn actigraphy. An unsupervised Hidden-Markov Model algorithm provided actigraphy-measured night time sleep without the guidance of reported sleep times. Waist-to-height ratio and age-and-sex-specific body mass index characterised weight status. Comparison of methods were assessed with consistency in quintile divisions and Spearman correlations. Associations between sleep and weight status were assessed with adjusted regression models. Participants included 638 children (49% girls) with a mean ± SD age of 4.76 ± 0.89. On weekdays, 98%-99% of actigraphy-measured and parent-reported sleep estimates were classified in the same or adjacent quintile and were strongly correlated (rs  = 0.79-0.85, p < 0.001). On weekends, 84%-98% of actigraphy-measured and parent-reported sleep estimates were respectively classified and correlations were moderate to strong (rs  = 0.62-0.86, p < 0.001). Compared with actigraphy-measured sleep, parent-reported sleep had consistently earlier onset, later wake-up, and greater duration. Earlier actigraphy-measured weekday sleep onset and midpoint were associated with a higher body mass index (respective β-estimates: -0.63, p < 0.01 and -0.75, p < 0.01) and waist-to-height ratio (-0.004, p = 0.03 and -0.01, p = 0.02). Though the sleep estimation methods were consistent and correlated, actigraphy measures should be favoured as they are more objective and sensitive to identifying associations between sleep timing and weight status compared with parent reports.

Accelerometry-assessed sleep clusters and cardiometabolic risk factors in adolescents

OBJECTIVE

This study aimed to identify sleep clusters based on objective multidimensional sleep characteristics and test their associations with adolescent cardiometabolic health.

METHODS

The authors included 1090 participants aged 14.3 to 16.4 years (mean = 15.2 years) who wore 7-day accelerometers during the 15-year follow-up of the German Infant Study on the influence of Nutrition Intervention PLUS environmental and genetic influences on allergy development (GINIplus) and the Influence of Lifestyle factors on the development of the Immune System and Allergies in East and West Germany (LISA) birth cohorts. K-means cluster analysis was performed across 12 sleep characteristics reflecting sleep quantity, quality, schedule, variability, and regularity. Cardiometabolic risk factors included fat mass index (FMI), blood pressure, triglycerides, high-density lipoprotein cholesterol, high-sensitivity C-reactive protein, and insulin resistance (n = 505). Linear and logistic regression models were examined.

RESULTS

Five sleep clusters were identified: good sleep (n = 337); delayed sleep phase (n = 244); sleep irregularity and variability (n = 108); fragmented sleep (n = 313); and prolonged sleep latency (n = 88). The "prolonged sleep latency" cluster was associated with increased sex-scaled FMI (β = 0.39, 95% CI: 0.15-0.62) compared with the "good sleep" cluster. The "sleep irregularity and variability" cluster was associated with increased odds of high triglycerides only in male individuals (odds ratio: 9.50, 95% CI: 3.22-28.07), but this finding was not confirmed in linear models.

CONCLUSIONS

The prolonged sleep latency cluster was associated with higher FMI in adolescents, whereas the sleep irregularity and variability cluster was specifically linked to elevated triglycerides (≥1.7 mmol/L) in male individuals.

Obesogenic sleep patterns among Chinese preschool children: A latent profile and transition analysis of the association sleep patterns and obesity risk

OBJECTIVE

This paper utilized a person-centered approach to examine whether sleep patterns on school and free days are associated with obesity risk in preschool children aged 3-6 years.

METHODS

The cross-sectional analysis included 204 children from the Wuhan Healthy Start Project with valid sleep data in at least four consecutive days gathered via Actigraph GT3X+. Based on three domains of sleep duration, sleep onset, and sleep offset, we used latent profile analysis to identify distinct sleep patterns on school and free days separately. Additionally, we conducted latent transition analysis to explore the probabilities of sleep patterns transitions between school and free days. The multivariate logistic regression model investigated the associations of sleep patterns with overweight/obesity (OWO) (BMI ≥ age- and sex-specific 85th percentile) and abdominal obesity (AO) (WC ≥ age- and sex-specific 75th percentile).

RESULTS

Two sleep patterns were identified for school days: "EL-sc" (early-to-sleep/longer-duration) (n = 119; 58.3%) and "LS-sc" (late-to-sleep/shorter-duration) (n = 85; 41.7%). Similarly, "LES-fr" (late-to-sleep/early-to-wake/shorter-duration) (n = 118; 57.8%) and "ELL-fr" (early-to-sleep/late-to-wake/longer-duration) (n = 86; 42.2%) patterns were identified for free days. LTA categorized the participants into four distinct transition groups, i.e., "EL-sc→ELL-fr" (32.9%), "EL-sc→LES-fr" (24.0%), "LS-sc→LES-fr" (33.8%), and "LS-sc→ELL-fr" (9.3%). Compared with the "ELsc→ELL-fr", the "LS-sc→LES-fr" had a higher risk of OWO (AOR 4.76; 95% CI: 1.39-20.33) and AO (AOR, 2.78; 95% CI, 1.21-6.62), respectively. Neither "EL-sc→LES-fr" (AOR, 1.11; 95% CI, 0.14-6.67) nor "LS-sc→ELL-fr" (AOR, 0.74; 95% CI, 0.03-6.14) was significantly associated with OWO. Likewise, no significant association was observed for "EL-sc→LES-fr" (AOR, 0.96; 95% CI, 0.35-2.62) and "LS-sc→ELL-fr" (AOR, 0.56; 95% CI, 0.11-2.18) with AO.

CONCLUSIONS

"LS-sc→LES-fr" pattern is significantly associated with an increased risk of general and abdominal obesity, indicating its obesogenic nature. Furthermore, although not statistically associated with obesity outcomes, "LS-sc→ELL-fr" and "EL-sc→LES-fr" patterns exhibit a semi-obesogenic characteristic. In addition, we identified a concerning trend that preschool children are at risk of transitioning to and persisting in sleep patterns characterized by delayed and shorter sleep. These findings underscore the importance of implementing interventions and strategies to address sleep patterns as a crucial step to minimize the risk of obesity.

Secular trends of sleep-wake patterns in Hong Kong preschoolers

OBJECTIVE

To evaluate the secular trends of sleep-wake patterns of Hong Kong preschool children.

METHODS

Kindergartens from the four geographical regions of Hong Kong were randomly invited to take part in a sleep survey in 2012 and again in 2018. The parent-completed questionnaire provided information on socioeconomic status (SES), children's, and parental sleep-wake patterns. Secular trends and risk factors associated with short sleep duration in preschoolers were explored.

RESULTS

A sample of 5048 preschool children was included in the secular comparison, with 2306 and 2742 from the 2012 and 2018 surveys, respectively. A higher percentage of children in 2018 (41.1% vs 26.7%, p < 0.001) did not achieve the recommended sleep duration. During the survey years, sleep duration decreased by 13 ([95%CI: 18.5 to -8.1]) and 18 min ([95%CI: 23.6 to -12.2]) on weekdays and weekends, respectively. The overall trend of nap decrease was not significant. Sleep onset latency significantly increased on both weekdays (6 min [95%CI: 3.5 to 8.5]) and weekends (7 min [95%CI: 4.7 to 9.9]). Children's sleep duration was positively correlated with parental sleep duration with a correlation coefficient ranging from 0.16 to 0.27 (p < 0.001).

CONCLUSIONS

A significant proportion of Hong Kong preschool children did not achieve the recommended amount of sleep. A downward secular trend in sleep duration was observed during the survey period. Public health measures to improve sleep duration in preschool children should be a high priority.

Pediatric obesity-Long-term consequences and effect of weight loss

Childhood obesity is, according to the WHO, one of the most serious challenges of the 21st century. More than 100 million children have obesity today. Already during childhood, almost all organs are at risk of being affected by obesity. In this review, we present the current knowledge about diseases associated with childhood obesity and how they are affected by weight loss. One major causative factor is obesity-induced low-grade chronic inflammation, which can be observed already in preschool children. This inflammation-together with endocrine, paracrine, and metabolic effects of obesity-increases the long-term risk for several severe diseases. Type 2 diabetes is increasingly prevalent in adolescents and young adults who have had obesity during childhood. When it is diagnosed in young individuals, the morbidity and mortality rate is higher than when it occurs later in life, and more dangerous than type 1 diabetes. Childhood obesity also increases the risk for several autoimmune diseases such as multiple sclerosis, Crohn's disease, arthritis, and type 1 diabetes and it is well established that childhood obesity also increases the risk for cardiovascular disease. Consequently, childhood obesity increases the risk for premature mortality, and the mortality rate is three times higher already before 30 years of age compared with the normal population. The risks associated with childhood obesity are modified by weight loss. However, the risk reduction is affected by the age at which weight loss occurs. In general, early weight loss-that is, before puberty-is more beneficial, but there are marked disease-specific differences.

Effect of sleep disturbance on biomarkers related to the development of adverse health outcomes: A systematic review of the human literature

Literature suggests that unrestricted and undisturbed sleep is vital for basic human function and performance; however, it is unclear as to what amount of sleep disturbance leads to dysregulation in biomarkers, which may underscore the development of adverse health effects. This systematic review aims to identify the amount of sleep disturbance that contributes to biomarker changes as a potential precursor to the development of adverse health effects. English-language comparative studies available in PubMed, Cochrane Central, EMBASE, and CINAHL databases from 1 January 1980 to 31 July 2021 were searched. Where possible, random-effects meta-analyses were used to examine the effect of sleep disturbances on adverse health effects. The risk of bias of individual studies was assessed using the Cochrane Risk of Bias Tool and the Risk of Bias of Nonrandomised Studies - of Exposures instruments and the certainty of the body of evidence for each outcome was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. The search identified 92 primary studies reporting on blood pressure, hypertension, heart rate, cardiac arrhythmia, cardiac output, waist circumference, cortisol, adrenaline, noradrenaline, immune system markers, glucose, insulin, cholesterol, and triglyceride levels. Although some meta-analyses suggested there may be an association between sleep disturbances and certain outcomes, the certainty in the evidence was very low due to concerns with risk of bias, inconsistency across exposures, populations, and imprecision in the estimates of effects. Further research is needed to explore the point at which types, levels and duration of sleep disturbances may begin to increase the risk of developing adverse health outcomes to inform and tailor health interventions.

Short sleep duration at night in 2.5-year-old children is associated with childhood obesity at age 5.5 years: The Japanese children cohort study

BACKGROUND

Obesity in children contributes to higher risks of various chronic diseases in adulthood and the prevalence has increased worldwide including Japan.

OBJECTIVES

This study aims to examine the association between sleep duration at night in children aged 2.5 years and the subsequent risk of obesity at age 5.5 years.

METHODS

This study is embedded in the Longitudinal Survey on Babies Born in the 21st Century, which recruited families who had a child born in Japan in 2001. The multivariable logistic regression models were applied to calculate odds ratios (OR) and 95 % confidence intervals (CI) of childhood obesity at 5.5 years, defined as percentage of overweight (POW) ≥ 20 % and body mass index (BMI) ≥ 95th percentile of this study population according to sleep duration at night collected at 2.5 years child age.

RESULTS

Among 25,378 children, 2.6 % and 3.7 % were obese at age 5.5 years defined by POW and BMI respectively. Compared with night sleep duration > 11 h/d, shorter sleep durations in 2.5 years-old children were associated with higher risk of obesity at 5.5 years; the multivariable ORs (95 %CI) were 1.05 (0.81-1.35), 1.23 (0.93-1.62) and 1.54 (1.04-2.31) for sleep duration 10, 9 and ≤ 8 h/d, respectively; p-trend = 0.03. The observed association differed according to the children (child's sex, napping habits, and children frequently play at park), and family characteristics (mother's age at delivery and mother's level of education).

CONCLUSION

Short night sleep duration among girls aged 2.5 years was associated with risk of obesity at age 5.5 years, suggesting the importance of sufficient sleep duration at night for the prevention of obesity.

Associations Between Sleep and Metabolic Outcomes in Preadolescent Children

Context

Growing evidence suggests an important role for sleep for the metabolic health of children.

Objective

We aimed to determine how sleep is related to insulin sensitivity, insulin secretion, beta-cell function, and adiposity (BMI z-scores, body fat %, waist to height ratio) using objectively measured sleep and oral glucose tolerance test (OGTT)-derived measures.

Methods

Sixty-two children aged 7-11 years, born at Kaiser Permanente Southern California, wore wrist accelerometers for 7 days to objectively measure sleep, completed an OGTT, and had anthropometric measures (height [cm], weight [kg], waist [cm], body fat [%]) collected. Using linear regression, associations between Matsuda insulin sensitivity index (ISI), insulinogenic index (IGI), disposition index (DI), BMI z-score, waist to height ratio, and body fat % with sleep parameters [total sleep time (TST; min), sleep efficiency (SE; %), time in bed (TIB; min), wake after sleep onset (WASO; min), and sleep latency (SL; min)] were assessed. Body fat % was tested as a mediator of the relationship between TST and ISI.

Results

Longer TST was associated with better insulin sensitivity (P = 0.02), but not after adjusting for body fat %. Sleep parameters were not associated with IGI or DI. Longer TST was associated with lower % body fat (P = 0.01) and lower waist-to-height-ratios (P = 0.05). Body fat % explained 62% (P = 0.01) of the relationship between TST and ISI. Longer TIB was associated with lower adiposity measures (P < 0.05). There were no associations between SE, WASO, or SL and metabolic outcomes.

Conclusion

Objectively measured sleep duration was associated with lower adiposity, and the relationship between sleep duration and ISI appeared partly through adiposity levels in preadolescent children. Longer sleep duration may be important for metabolic health.

Childhood diabetes and sleep

Sleep modulates glucose metabolism, both in healthy states and in disease. Alterations in sleep duration (insufficient and excessive) and obstructive sleep apnea may have reciprocal ties with obesity, insulin resistance and Type 2 diabetes, as demonstrated by emerging evidence in children and adolescents. Type 1 diabetes is also associated with sleep disturbances due to the influence of wide glycemic fluctuations upon sleep architecture, the need to treat nocturnal hypoglycemia, and the need for glucose monitoring and insulin delivery technologies. In this article, we provide an extensive and critical review on published pediatric literature regarding these topics, reviewing both epidemiologic and qualitative data, and provide an overview of the pathophysiology linking sleep with disorders of glucose homeostasis.

Socioeconomic disadvantages and vulnerability to the pandemic among children and youth: A macro-level investigation of American counties

This study intends to reveal the underlying structural inequity in vulnerability to infection of the novel coronavirus disease pandemic among children and youth. Using multi-source data from New York Times novel coronavirus disease tracking project and County Health Rankings & Roadmap Program, this study shows that children and youth in socioeconomically disadvantaged status are faced with disproportionate risk of infection in this pandemic. On the county level, socioeconomic disadvantages (i.e., single parent family, low birthweight, severe housing problems) contribute to the confirmed cases and death cases of the novel coronavirus disease. Policymakers should pay more attention to this vulnerable group to implement more targeted and effective epidemic prevention and control.

Physical activity in early childhood: a five-year longitudinal analysis of patterns and correlates

Background

Knowledge on longitudinal patterns and related factors of young children’s physical activity (PA) is still scarce. Therefore, the aim of this study was to examine patterns and changes of accelerometer-measured PA over time in two to six-year-old children. Furthermore, the aim was to investigate if parental PA, socioeconomic status, sex, weight status, and motor skills are related to child PA over time, using prospective cohort data from a clustered randomized controlled trial.

Methods

One hundred and six children (52% girls) and their parents had PA measured yearly from age two to six with an Actigraph GT3X. The actigraph was worn on the non-dominant wrist for one week; anthropometric data and motor skills, as well as background information, was collected simultaneously. The outcome was counts per minute from the vector magnitude, and linear mixed-effect models were used to answer the research questions.

Results

Among the children, accelerometer-measured PA increased on average by 11% per year from two years of age (mean 3170 cpm (3007-3334 95% CI)) onwards to six years of age (mean 4369 cpm (4207-4533 95% CI)). From three years of age, children were more active on weekdays than on weekend days. The rate of difference varied across low, medium, and highly active children (based on tertiles). No significant differences in weekdays/weekend PA among the lowest active children was found. Despite this, they were still significantly less active on weekend days than the most active children. Maternal, but not paternal PA was found to be significantly positively related to child PA over time, with a medium to large effect size. But no significant relationships were found between child PA and sex, weight status, or socioeconomic status.

Conclusions

PA increased on average with 11% per year, similarly for boys and girls. From three years of age children were more active during weekdays than weekend days. These results indicate that child PA benefits from active stimulation by parents and care takers already from early ages. It is important to identify attributes of possible intervention designs for weekend days for families with young children as well as characterize the least active children.

Trial registration

Early STOPP was prospectively registered in the clinical trials registry: clinicaltrials.gov, ID NCT01198847

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-022-01289-x.

Associations of sleep with food cravings and loss-of-control eating in youth: An ecological momentary assessment study

BACKGROUND

Inconsistent sleep patterns may promote excess weight gain by increasing food cravings and loss-of-control (LOC)-eating; however, these relationships have not been elucidated in youth.

OBJECTIVE

We tested whether sleep duration and timing were associated with food cravings and LOC-eating.

METHOD

For 14 days, youths wore actigraphy monitors to assess sleep and reported severity of food cravings and LOC-eating using ecological momentary assessment. Generalized linear mixed models tested the associations between weekly and nightly shifts in facets of sleep (i.e., duration, onset, midpoint, and waketime) and next-day food cravings and LOC-eating. Models were re-run adjusting for relevant covariates (e.g., age, sex, adiposity).

RESULTS

Among 48 youths (12.88 ± 2.69 years, 68.8% female, 33.3% with overweight/obesity), neither weekly nor nightly facets of sleep were significantly associated with food cravings (ps = 0.08-0.93). Youths with shorter weekly sleep duration (est. ß = -0.31, p = 0.004), earlier weekly midpoints (est. ß = -0.47, p = 0.010) and later weekly waketimes (est. ß = 0.49, p = 0.010) reported greater LOC-eating severity; findings persisted in adjusted models.

CONCLUSIONS

In youth, weekly, but not nightly, shifts in multiple facets of sleep were associated with LOC-eating severity; associations were not significant for food cravings. Sleep should be assessed as a potentially modifiable target in paediatric LOC-eating and obesity prevention programs.

Sleep and physical activity patterns in adults and children with Bardet-Biedl syndrome

Background

Overweight and obesity are common features of the rare disease Bardet–Biedl syndrome (BBS). Sleep and physical activity are behaviors that might impact overweight and obesity and thus may play a key role in the health and well-being of people with BBS. Objectively-measured sleep and physical activity patterns in people with BBS are not well known. We evaluated objectively-measured sleep and physical activity patterns in the largest cohort to date of people with BBS.

Results

Short sleep duration, assessed using wrist-worn accelerometers, was common in both children and adults with BBS. Only 7 (10%) of adults and 6 (8%) of children met age-specific sleep duration recommendations. Most adults 64 (90%) achieved recommended sleep efficiency. The majority of children 26 (67%) age 6–12 years achieved recommended sleep efficiency, but among children age 13–18, only 18 (47%). In both adults and children, sleep duration was significantly negatively correlated with duration of prolonged sedentary time. In children age 6–12 sleep duration was also significantly related to total activity score, children with lower sleep duration had lower total activity scores.

Conclusions

Insufficient sleep duration is very common in people with BBS. Prolonged sedentary time and short sleep duration are both potentially important health-related behaviors to target for intervention in people with BBS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01911-4.

Sleep in the Hospitalized Child: A Contemporary Review

Acute illness and hospitalization introduce several risk factors for sleep disruption in children that can negatively affect recovery and healing and potentially compromise long-term cognition and executive function. The hospital setting is not optimized for pediatric sleep promotion, and many of the pharmacologic interventions intended to promote sleep in the hospital actually may have deleterious effects on sleep quality and quantity. To date, evidence to support pharmacologic sleep promotion in the pediatric inpatient setting is sparse. Therefore, nonpharmacologic interventions to optimize sleep-wake patterns are of highest yield in a vulnerable population of patients undergoing active neurocognitive development. In this review, we briefly examine what is known about healthy sleep in children and describe risk factors for sleep disturbances, available sleep measurement tools, and potential interventions for sleep promotion in the pediatric inpatient setting.

The association of actigraphic sleep measures and physical activity with excess weight and adiposity in kindergarteners

Insufficient sleep duration and physical activity (PA) are known risk factors for overweight and obesity in children; however, there are no studies on comprehensive associations of objectively-measured sleep parameters and PA with excess weight and excess adiposity in kindergarteners. Therefore, the aim of this study was to determine the associations between objectively measured sleep parameters and PA with excess weight and excess adiposity, defined as BMI ≥ 85th percentile and body fat percentage (BFP) ≥ 85th percentile, respectively. Sleep parameters and PA were measured in 676 subjects aged 5–6 years using accelerometers for 7 days, worn at the participant’s hip. Bioelectrical impedance analysis was used to estimate BFP. In the total sample, lower sleep duration, sleep efficiency, vigorous PA and the number of steps per day were associated with excess weight. However, excess adiposity was associated with lower sleep duration, total PA, vigorous PA, moderate-to-vigorous physical activity (MVPA) and the number of steps per day. Logistic regression by the stepwise progressive method showed that the strongest predictor of excess adiposity in boys and girls was vigorous PA, while the strongest predictor of excess weight in boys was sleep efficiency. A holistic approach to health targeting all of these factors synergistically is needed to optimize the effectiveness of obesity prevention and treatment interventions.

Sleep timing and sleep problems of preschoolers in Aotearoa/New Zealand: relationships with ethnicity and socioeconomic position

OBJECTIVES

To provide descriptive sleep data and explore sleep inequities, we investigated maternal reports of when and how well Māori (Indigenous) and non-Māori preschoolers sleep, and examined relationships between ethnicity (child and maternal), socioeconomic position (SEP) and sleep timing and problems of 3-4 year old children in Aotearoa/New Zealand (NZ).

METHODS

This study involved cross-sectional analysis of data from the Moe Kura: Mother and Child, Sleep and Wellbeing in Aotearoa/New Zealand longitudinal study. Log-binomial regression models were used to investigate associations between child and maternal demographic variables and preschooler bedtimes, social jetlag and maternally-reported sleep problems. Child models included child ethnicity, child gender, area- and individual-level deprivation. Maternal models included maternal ethnicity, maternal age, area- and individual-level deprivation.

RESULTS

340 Māori and 570 non-Māori preschoolers and their mothers participated. Māori preschoolers had later average bedtimes and wake times than non-Māori preschoolers. Ethnicity and area-level deprivation were independently associated with later bedtimes. Ethnicity was associated with social jetlag and sleep problems, independent of SEP. Individual-level deprivation was associated with problems falling asleep. Preschoolers of Māori mothers in least deprived areas were more likely to have problems falling asleep than preschoolers of non-Māori mothers in least deprived areas.

CONCLUSIONS

Research is needed to understand what sleep timing differences mean for preschoolers' wellbeing in NZ. Fundamental causes of social and economic disadvantage experienced by Indigenous children and mothers and by families who hold low SEP must be addressed, in order to eliminate sleep health inequities in early childhood.

Time for bed! Earlier sleep onset is associated with longer nighttime sleep duration during infancy

OBJECTIVE/BACKGROUND

Clinical recommendations include putting infants to bed using a consistent bedtime routine at an appropriate hour to promote longer nighttime sleep. Actigraphy was used in this exploratory study to examine how bedtime routines and nighttime sleep onset were associated with nighttime total sleep time (TST) and efficiency from 6 to 24 weeks of age.

PATIENTS/METHODS

Infants (n = 24) wore sleep actigraphs for three, one-week periods at 6, 15, and 24 weeks of age. Nighttime TST, sleep efficiency, sleep onset and offset were quantified. Mothers reported on infant bedtime routines using the Brief Infant Sleep Questionnaire at each age. Multilevel models examined between- and within-person associations.

RESULTS

As infants aged, sleep onset was earlier, and bedtime routines became shorter (p's < 0.05). Infants fell asleep between 7 and 8:00PM on 24% of the nights. Most mothers (70%) reported that they often fed infants to sleep for the night. For every 1 h earlier in infants' usual sleep onset, nighttime TST was 34.4 min longer that night (p < 0.01). Infants with earlier than usual sleep onset had slightly earlier sleep offset the next morning (8.4 min for every 1 h earlier in onset; p = 0.02). Between-person analyses showed similar patterns. Infants with a more consistent bedtime routine and who were not typically fed to sleep at bedtime had longer nighttime TST at 6 weeks, with a trend or no association at later ages.

CONCLUSION

Infants who fell asleep earlier also slept longer at night. Keeping infants up later in hopes of them sleeping in longer may be counterproductive.