Failure of an electric rocking device to improve neonatal sleep.

AIM: We wanted to investigate whether an electric rocking device (Swing2Sleep, Neumünster, Germany), sold with the claim to promote infant sleep, would increase total sleep time or reduce sleep latency once infants are put therein. METHODS: In a randomised crossover design, 20 infants (median gestational age at birth 31.7 weeks, range 25-39) were placed to sleep either first with the device rocking, then not rocking (or vice versa) for 5-7 h each. The device consisted of a hammock with three spiral springs that performed vertical swings at a rate of 100/min and an amplitude of 2.5 cm. RESULTS: There was no significant difference in %time spent asleep (83 (22-97) vs. 85% (49-96)), sleep latency (7.7 (2-45) vs. 12.3 (4-42) min), sleep fragmentation (1.3 (0.5-2.3) vs. 1.1 (0.2-5.5)) or efficiency (0.8 (0.2-1.0) vs. 0.9 (0.5-1.0)) between both conditions. CONCLUSION: At its recommended settings, the device did not achieve its intended effect in these infants.

A systematic review of progranulin concentrations in biofluids in over 7,000 people-assessing the pathogenicity of GRN mutations and other influencing factors.

BACKGROUND: Pathogenic heterozygous mutations in the progranulin gene (GRN) are a key cause of frontotemporal dementia (FTD), leading to significantly reduced biofluid concentrations of the progranulin protein (PGRN). This has led to a number of ongoing therapeutic trials aiming to treat this form of FTD by increasing PGRN levels in mutation carriers. However, we currently lack a complete understanding of factors that affect PGRN levels and potential variation in measurement methods. Here, we aimed to address this gap in knowledge by systematically reviewing published literature on biofluid PGRN concentrations. METHODS: Published data including biofluid PGRN concentration, age, sex, diagnosis and GRN mutation were collected for 7071 individuals from 75 publications. The majority of analyses (72%) had focused on plasma PGRN concentrations, with many of these (56%) measured with a single assay type (Adipogen) and so the influence of mutation type, age at onset, sex, and diagnosis were investigated in this subset of the data. RESULTS: We established a plasma PGRN concentration cut-off between pathogenic mutation carriers and non-carriers of 74.8 ng/mL using the Adipogen assay based on 3301 individuals, with a CSF concentration cut-off of 3.43 ng/mL. Plasma PGRN concentration varied by GRN mutation type as well as by clinical diagnosis in those without a GRN mutation. Plasma PGRN concentration was significantly higher in women than men in GRN mutation carriers (p = 0.007) with a trend in non-carriers (p = 0.062), and there was a significant but weak positive correlation with age in both GRN mutation carriers and non-carriers. No significant association was seen with weight or with TMEM106B rs1990622 genotype. However, higher plasma PGRN levels were seen in those with the GRN rs5848 CC genotype in both GRN mutation carriers and non-carriers. CONCLUSIONS: These results further support the usefulness of PGRN concentration for the identification of the large majority of pathogenic mutations in the GRN gene. Furthermore, these results highlight the importance of considering additional factors, such as mutation type, sex and age when interpreting PGRN concentrations. This will be particularly important as we enter the era of trials for progranulin-associated FTD.

Onsite versus home-office: differences in sleep patterns according to workplace.

Background and objective: This study aimed to evaluate the sleep patterns of students and employees working onsite versus those working from home during the COVID-19 pandemic using actigraphy. Methods: A total of 75 students/employees (onsite: N = 40, home-office: N = 35; age range: 19-56 years; 32% male; 42.7% students, 49.3% employees) were studied between December 2020 and January 2022 using actigraphy, a sleep diary, and an online questionnaire assessing sociodemographics and morningness-eveningness. Independent-sample t-tests, paired-sample tests, and a multivariate general linear model adjusting for age (fixed factors: sex and work environment) were applied. Results: Overall, onsite workers had significantly earlier rise times (7:05 [SD: 1:11] versus 7:44 [1:08] hours) and midpoints of sleep (2:57 [0:58] versus 3:33 [0:58] hours) on weekdays compared to home-office workers. Sleep efficiency, sleep duration, variability of sleep timing, and social jetlag did not differ between the groups. Discussion: Home-office workers showed a delay in sleep timing that did not affect any other sleep parameters such as sleep efficiency or nighttime sleep duration. The work environment had only marginal impact on sleep patterns and thus sleep health in this sample. Sleep timing variability did not differ between groups. Supplementary Information: The online version of this article (10.1007/s11818-023-00408-5) contains supplementary material 1 and 2, which is available to authorized users.

Prospective Evaluation of Children with Robin Sequence following Tübingen Palatal Plate Therapy.

BACKGROUND: To assess the long-term functional orthodontic outcome of the Tübingen palatal plate (TPP) in children with Robin sequence (RS) in comparison to age- and sex-matched healthy controls. METHODS: Between 09/2019 and 10/2020, we performed orthodontic assessments in 41 children at our Department of Orthodontics. Included were patients with RS (17 non-syndromic; four syndromic) and healthy controls (n = 22, average age in both groups 9.9 y). Facial analyses of 2D images, digital study casts and cephalometric measurements were made. RESULTS: The orthodontic examinations showed no statistically significant group differences regarding functional extraoral, intraoral and pharyngeal parameters, or in skeletal patterns. The relationship between the upper and lower incisors was significantly increased (overjet 4 (2-10) vs. 3 (0-9) mm; p = 0.01) with a significant deficit in the lower face proportions (Jaw Index 4.15 (1.9-9.6) vs. 2.98 (0-9); p = 0.02; Facial convexity angle 157 (149-173) vs. 159 (149-170); p = 0.01). CONCLUSION: Children with RS treated with the TPP showed normal long-term functional orthodontic outcomes, thanks to the functional adaption of the stomatognathic system. However, soft tissue growth did not completely match skeletal growth, resulting in a more convex facial profile.

Sleep and neurocognitive outcome in primary school children with Robin Sequence.

STUDY OBJECTIVES: To investigate neurocognitive and behavioral outcomes at primary school age in relation to obstructive sleep apnea (OSA) in children with Robin sequence (RS) treated with the Tuebingen palatal plate in infancy and to assess the impact of OSA in these patients. METHODS: Forty-two primary school-aged children (n = 21 with RS, n = 21 age- and sex-matched controls) underwent polysomnography, intelligence testing ("Wechsler Intelligence Scale for Children-Fifth Edition" [WISC-V]), and anthropometrics. Families completed a 7-day sleep diary and questionnaires on sleep and behavior (Children's Sleep Habits Questionnaire [CSHQ] and the Child Behavior Checklist [CBCL]). RESULTS: In children with RS (17 non-syndromic, four syndromic; median age 9.7 [8.5-10.8] years), the obstructive apnea-hypopnea index (OAHI) was significantly higher than in controls (1.3 [0.4-2.7]/h vs. 0.4 [0.1-0.6]/h). Two syndromic children with RS were already on nocturnal respiratory support for OSA prior to our study, and one non-syndromic child was diagnosed with severe OSA (OAHI 57/h) despite an unremarkable medical history and questionnaire. The overall intelligence quotient in children with RS was within the normal range and did not differ between children with RS and healthy peers (102 vs. 108, p = .05). However, children with RS had values in the at-risk clinical range for externalizing behavior. CONCLUSIONS: These children with RS showed an increased risk of OSA and behavioral problems, suggesting regular screening for OSA throughout childhood. Neurocognitive scores in children with RS were within the normal range after adequate treatment of OSA during infancy.

Interventions for Promoting Meconium Passage in Very Preterm Infants-A Survey of Current Practice at Tertiary Neonatal Centers in Germany.

Meconium passage is often delayed in preterm infants. Faster meconium passage appears to shorten the time to full enteral feeds, while severely delayed meconium passage may indicate meconium obstruction. Neonatologists often intervene to promote meconium passage, assuming that benefits outweigh potential risks such as necrotizing enterocolitis (NEC). We performed an anonymous online survey on different approaches to facilitate meconium passage among tertiary neonatal intensive care units (NICUs) in Germany between February 2022 and April 2022. We collected information on enteral nutrition, gastrointestinal complications, and interventions to promote meconium passage. We received 102 completed questionnaires (response rate 64.6%). All responders used interventions to promote meconium passage, including enemas (92.0%), orally applied contrast agents (61.8%), polyethylene glycol (PEG) (46.1%), acetylcysteine (19.6%), glycerin suppositories (11.0%), and maltodextrin (8.8%). There was substantial heterogeneity among NICUs regarding frequency, composition, and mode of administration. We found no differences in NEC incidence between users and nonusers of glycerin enemas, high or low osmolar contrast agents, or PEG. There is wide variability in interventions used to promote meconium passage in German NICUs, with little or no evidence for their efficacy and safety. Within this study design, we could not identify an increased risk of NEC with any intervention reported.

Should obstructive hypopneas be included when analyzing sleep studies in infants with Robin Sequence?

OBJECTIVE: We have used an obstructive apnea index of ≥3 as treatment indication for infants with Robin sequence (RS), while the obstructive apnea-hypopnea index (OAHI) and a threshold of ≥5 is often used internationally. We wanted to know whether these two result in similar indications, and what the interobserver variability is with either asessement. METHODS: Twenty lab-based overnight sleep recordings from infants with isolated RS (median age: 7 days, range 2-38) were scored based on the 2020 American Academy of Sleep Medicine guidelines, including or excluding obstructive hypopneas. RESULTS: Median obstructive apnea index (OAI) was 18 (interquartile range: 7.6-38) including only apneas, and 35 (18-54) if obstructive hypopneas were also considered as respiratory events (OAHI). Obstructive sleep apnea (OSA) severity was re-classified from moderate to severe for two infants when obstructive hypopneas were also considered, but this did not lead to a change in clinical treatment decisions for either infant. Median interobserver agreement was 0.86 (95% CI 0.70-0.94) for the OAI, and 0.60 (0.05-0.84) for the OAHI. CONCLUSION: Inclusion of obstructive hypopneas when assessing OSA severity in RS infants doubled the obstructive event rate, but impaired interobserver agreement and would not have changed clinical management.

Associations of sleep-related behaviors and the sleep environment at infant age one month with sleep patterns in infants five months later.

OBJECTIVE: To characterize family and environmental correlates of sleep patterns that may contribute to differences in infant sleep. METHODS: We studied 313 infants in the Rise & SHINE (Sleep Health in Infancy & Early Childhood study) cohort. Our main exposures were the parent-reported sleep environment, feeding method and sleep parenting strategies at infant age one month. The main outcomes were nighttime sleep duration, longest nighttime sleep and number of awakenings measured by actigraphy at age six months. We used multivariable linear regression models to examine associations, and secondarily also explored the role of sleep-related environmental exposures in mediating previously observed associations of racial/ethnicity and parental education with infant sleep characteristics. RESULTS: In adjusted models, a non-dark sleep environment (versus an always dark sleep location) and taking the baby to parent's bed when awake at night (versus no co-sleeping) were associated with 28 (95% CI, -45, -11) and 18 (95% CI, -33, -4) minutes less sleep at night, respectively. Bottle feeding at bedtime was associated with 62 (95% CI, 21, 103) minutes additional longest nighttime sleep period. Exploratory mediation analyses suggested a modest mediating role of a non-dark sleep environment on racial/ethnic and educational differences in sleep duration. CONCLUSIONS: Infant sleep duration was positively associated with a dark sleep environment and a focal feed at bedtime while taking the baby to the parent's bed was associated with reduced infant sleep. Modifying the sleep environment and practices may improve infant sleep and reduce sleep health disparities.

Validity of chronotype questionnaires in adolescents: Correlations with actigraphy.

There are only a few validated chronotype and morningness-eveningness questionnaires for adolescents. We evaluated three such questionnaires, namely Morningness-Eveningness Stability Scale improved; reduced Morningness-Eveningness Questionnaire for Children and Adolescents; and Composite Scale of Morningness in adolescents against actigraphy. Fifty-five healthy 13- to 16-year-old adolescents completed the Morningness-Eveningness Stability Scale improved, reduced Morningness-Eveningness Questionnaire for Children and Adolescents, Composite Scale of Morningness, and Pediatric Daytime Sleepiness Scale, and provided a 7-day actigraphy and sleep diary recording about their sleep-wake patterns. We examined the correlations between sleep-wake and activity parameters, and the questionnaires. The influence of age and sex on chronotype classification was studied using uni- and multivariate analyses. All three chronotype questionnaires showed good internal consistency and convergent validity. Spearman correlations reflected less daytime sleepiness, earlier sleep times, midpoints of sleep, and acrophase in morning-oriented participants. Evening-oriented participants had more sleepiness and later respective sleep-wake times. Chronotype classification differed significantly between questionnaires. The Composite Scale of Morningness classified more participants as morning types when compared with the reduced Morningness-Eveningness Questionnaire for Children and Adolescents (12 versus 7, respectively), and fewer adolescents as evening types (5 versus 9, respectively). Age and sex had no significant influence on questionnaire scores. The Morningness-Eveningness Stability Scale improved, reduced Morningness-Eveningness Questionnaire for Children and Adolescents, and Composite Scale of Morningness are valid instruments to determine circadian preference in adolescents; however, chronotype classification from the Composite Scale of Morningness and reduced Morningness-Eveningness Questionnaire for Children and Adolescents cannot be used interchangeably.

Contextual and Parenting Factors Contribute to Shorter Sleep Among Hispanic/Latinx Compared to Non-Hispanic White Infants.

BACKGROUND: Sleep is an important aspect of child development and health. Disparities in childhood sleep have been observed as early as infancy, but little is known about the factors contributing to them. PURPOSE: The objective of this study was to examine whether intrinsic, contextual, and parenting factors contribute to differences in sleep duration between Hispanic/Latinx and non-Hispanic white infants at 6 months of age. METHODS: We analyzed data of 119 Hispanic/Latinx and 146 non-Hispanic white infants in Rise & SHINE, a prospective birth cohort study of mother-infant dyads. Mothers reported their infant's sleep patterns using the Brief Infant Sleep Questionnaire at 6 months. Mothers also completed surveys measuring intrinsic (sex, gestational length, and birth weight), contextual (cultural, environmental, and familial), and parenting (behaviors and practices) factors. We used multivariable linear and logistic regression analyses to examine the contributing effects of these clusters of variables on the association between racial/ethnic background and infant sleep duration. RESULTS: Hispanic/Latinx infants slept 38 min less than white infants at 6 months (ß: -0.63 [95% confidence interval: -1.07, -0.19]) and were nearly three times more likely to not meet the minimum sleep recommendation. The differences persisted after adjustment for intrinsic factors but were attenuated after additional adjustment for contextual and parenting factors, especially having a foreign-born mother and later bedtime. CONCLUSIONS: The results of this study demonstrate that differences in sleep duration among Hispanic/Latinx infants compared to their white counterparts are present as early as 6 months of age and that context and parenting matter.

Emergence of racial/ethnic and socioeconomic differences in objectively measured sleep-wake patterns in early infancy: results of the Rise & SHINE study.

STUDY OBJECTIVES: To characterize objectively assessed sleep-wake patterns in infants at approximately 1 month and 6 months and examine the differences among infants with different racial/ethnic backgrounds and household socioeconomic status (SES). METHODS: Full-term healthy singletons wore an ankle-placed actigraph at approximately 1 month and 6 months and parents completed sleep diaries. Associations of racial/ethnic and socioeconomic indices with sleep outcomes were examined using multivariable analyses. Covariates included sex, birth weight for gestational age z-score, age at assessment, maternal education, household income, bed-sharing, and breastfeeding. RESULTS: The sample included 306 infants, of whom 51% were female, 42.5% non-Hispanic white, 32.7% Hispanic, 17.3% Asian, and 7.5% black. Between 1 month and 6 months, night sleep duration increased by 65.7 minutes (95% CI: 55.4, 76.0), night awakenings decreased by 2.2 episodes (2.0, 2.4), and daytime sleep duration decreased by 73.3 minutes (66.4, 80.2). Compared to change in night sleep duration over this development period for white infants (82.3 minutes [66.5, 98.0]), night sleep increased less for Hispanic (48.9 minutes [30.8, 66.9]) and black infants (31.6 minutes [-5.9, 69.1]). Night sleep duration also increased less for infants with lower maternal education and household income. Asian infants had more frequent night awakenings. Adjustment for maternal education and household income attenuated all observed day and night sleep duration differences other than in Asians, where persistently reduced nighttime sleep at 6 months was observed. CONCLUSIONS: Racial/ethnic differences in sleep emerge in early infancy. Night and 24-hour sleep durations increase less in Hispanic and black infants compared to white infants, with differences largely explained by SES.

Associations between parent-reported and objectively measured sleep duration and timing in infants at age 6 months.

STUDY OBJECTIVES: To compare the estimates of sleep duration and timing from survey, diary, and actigraphy in infants at age 6 months, overall and by select demographics and other factors. METHODS: In total, 314 infants participating in the Rise & SHINE (Sleep Health in Infancy & Early Childhood study) cohort in Boston, MA, USA, wore an actigraph on their left ankle for 7 days. Parents concurrently completed a sleep diary and the expanded version of the Brief Infant Sleep Questionnaire. Concordance between parent-reported and objective sleep estimates was assessed using Bland-Altman plots, Spearman's rank correlations, intraclass correlations, and linear regression models. RESULTS: Mean infant age was 6.4 (0.6 SD) months; 51% were female and 42% were Non-Hispanic white. Mean total sleep duration using actigraphy was 526 (67 SD) minutes per night, 143 (42 SD) minutes per day, and 460 (100 SD) minutes during the longest nighttime sleep period. Relative to actigraphy, parent-completed survey and diary overestimated total day (by 29 and 31 minutes, respectively) and night sleep duration (67 and 43 minutes, respectively) and underestimated the longest sleep (58 minutes), with the highest agreement for sleep onset and offset timing (differences < 30 minutes). There was a tendency toward greater bias among short- and long-sleeping infants. Self-reporting bias for diary-measured longest nighttime sleep and total night sleep duration was higher in infants of parents reporting a problem with their baby's night awakenings and in low-income families, respectively. CONCLUSIONS: Our findings underscore the need to be cautious when comparing findings across studies using different sleep assessment methods.

Association of sleep characteristics with adiposity markers in children.

Background Accumulating evidence suggests a relationship between sleep alterations and overweight/obesity in children. Our aim was to investigate the association of sleep measures other than obstructive sleep apnea or sleep duration with overweight/obesity and metabolic function in children. Methods We conducted a prospective cohort study in school- aged children (aged 5 to 8 years, prepubertal, and 12 to 15 years, pubertal) with overweight/obesity and normal-weight children. All children underwent a standardized in-laboratory polysomnography followed by a fasting blood assessment for glucose and metabolic testing. Subjective sleep measures were investigated by a 7-day sleep diary and questionnaire. We analyzed prepubertal and pubertal groups separately using logistic regression and partial correlation analyses. Results A total of 151 participants were analyzed. Overweight/obese children had significantly higher odds for arousal index (prepubertal children: 1.28, Confidence interval (CI): 1.06, 1.67; pubertal children: 1.65, CI: 1.19, 2.29) than normal-weight children, independent of age and gender. In prepubertal children, arousal-index was positively associated with C-peptide (r=0.30, p=0.01), whereas Minimum O2 saturation was negatively associated with triglycerides (r=-0.34, p=0.005), adjusting for age and sex. However, associations were attenuated by further adjustment for body mass index standard deviation scores (BMI-SDS). In pubertal children, higher level of apnea-hypopnea-index and pCO2 predicted increased lipoprotein (a) levels (r=0.35, p=0.03 and r=0.40, p=0.01, respectively), independent of age, sex, and BMI-SDS. A negative association was found between pCO2 and high-density lipoprotein (HDL)-cholesterol (r=-0.40, p=0.01). Conclusions Overall, we report that sleep quality as measured by arousal index may be compromised by overweight and obesity in children and warrants attention in future intervention programs.

Chronotype, Social Jet Lag, and Cardiometabolic Risk Factors in Early Adolescence.

IMPORTANCE: Inadequate sleep duration and quality increase the risk of obesity. Sleep timing, while less studied, is important in adolescents because increasing evening preferences (chronotypes), early school start times, and irregular sleep schedules may cause circadian misalignment. OBJECTIVE: To investigate associations of chronotype and social jet lag with adiposity and cardiometabolic risk in young adolescents. DESIGN, SETTING, AND PARTICIPANTS: Starting in 1999, Project Viva recruited pregnant women from eastern Massachusetts. Mother-child in-person visits occurred throughout childhood. From January 23, 2012, to October 16, 2016, 804 adolescents aged 12 to 17 years completed 5 days or more of wrist actigraphy, questionnaires, and anthropometric measurements. A cross-sectional analysis using these data was conducted from April 31, 2018, to May 1, 2019. EXPOSURES: Chronotype, measured via a continuous scale with higher scores indicating greater evening preferences, and social jet lag, measured as the continuous difference in actigraphy sleep midpoint in hours from midnight on weekends vs weekdays, with higher values representing more delayed sleep timing on weekends. MAIN OUTCOMES AND MEASURES: Adiposity, measured via anthropometry and dual-energy x-ray absorptiometry. For a subset of 479 adolescents with blood samples, cardiometabolic risk scores were computed as the mean of 5 sex- and cohort-specific z scores for waist circumference, systolic blood pressure, inversely scaled high-density lipoprotein cholesterol, and log-transformed triglycerides and homeostatic model of insulin resistance. RESULTS: Among the 804 adolescents in the study, 418 were girls and 386 were boys, with a mean (SD) age of 13.2 (0.9) years. In multivariable models adjusted for age, puberty, season, and sociodemographics, associations of chronotype and social jet lag with adiposity varied by sex. For girls, greater evening preference was associated with a 0.58-cm (95% CI, 0.12-1.03 cm; P = .04 for interaction) higher waist circumference and 0.16 kg/m2 (95% CI, 0.01-0.31 kg/m2; P = .03 for interaction) higher fat mass index as measured by dual-energy x-ray absorptiometry; each hour of social jet lag was associated with a 1.19-cm (95% CI, 0.04-2.35 cm; P = .21 for interaction) higher waist circumference and 0.45 kg/m2 (95% CI, 0.09-0.82 kg/m2; P = .01 for interaction) higher fat mass index as measured by dual-energy x-ray absorptiometry. Associations of social jet lag and evening chronotypes persisted for many measures of adiposity after adjustment for sleep duration and other lifestyle behaviors. By contrast, no associations were observed in boys. There were no associations with the cardiometabolic risk score for either sex, although statistical power was low for this outcome. CONCLUSIONS AND RELEVANCE: Evening chronotypes and social jet lag were associated with greater adiposity in adolescent girls but not adolescent boys. Interventions aimed at improving sleep schedules may be useful for obesity prevention, especially in girls.

Association of Daily Rest-Activity Patterns With Adiposity and Cardiometabolic Risk Measures in Teens.

PURPOSE: Emerging data indicate that the timing and rhythms of energetic behaviors may influence metabolism and obesity risk. Our aim was to derive diurnal rest-activity patterns from actigraphy in adolescents and analyze associations with adiposity measures and cardiometabolic risk factors. METHODS: Adolescents in the Project Viva cohort wore a wrist actigraph over 7 days. We derived markers of daily rest-activity patterns from actigraphy using nonparametric models, generating measurements of relative amplitude (RA). RA reflects the normalized difference in activity measured during the most active 10-hour period and the least active 5-hour period, averaged over multiple 24-hour periods. Using multivariable-adjusted linear regression models, we estimated associations of RA and its components with markers of adiposity (body mass index, waist circumference, skinfolds, dual-energy X-ray absorptiometry fat mass) and cardiometabolic health (cardiometabolic risk score, derived as the mean of five sex-specific internal z-scores for waist circumference, systolic blood pressure, high-density lipoprotein cholesterol scaled inversely, and log-transformed triglycerides and homeostatic model assessment of insulin resistance). RESULTS: A total of 778 adolescents provided at least 5 days of valid actigraphy data. The average age was 13.2 (±.9) years, 52% were female, and the average RA was .9 (±.1). A higher RA reflecting higher activity during wakefulness and lower activity during the night was associated with more favorable indices of adiposity (e.g., -.35 kg/m2 lower body mass index per each .04 units increment of RA; 95% confidence interval: -.60 to -.09). CONCLUSIONS: In this large sample of adolescents, a higher RA emerged as a novel biomarker, associated with more favorable cardiometabolic profiles.

Associations Between Timing of Meals, Physical Activity, Light Exposure, and Sleep With Body Mass Index in Free-Living Adults.

BACKGROUND: This study tested if the timing of meals, physical activity, light exposure, and sleep cluster within individuals and are associated with body mass index (BMI) in a sample of free-living adults (N = 125). METHODS: Data were collected between November 2015 and March 2016 at the University of California, San Diego, Children's Hospital of Philadelphia, and Washington University in St Louis. Height and weight were measured, and BMI (kg/m2) was calculated. Sleep timing was estimated using actigraphy, and timing of meals, physical activity, and light exposure were self-reported using a smartphone application. General linear models estimated the mean BMI across time categories of behaviors, adjusting for covariates. A latent class analysis was used to identify patterns of timing variables that clustered within individuals and test for associations between identified patterns and BMI. RESULTS: Later exposure to outdoor light was associated with a lower BMI (P trend < .01). The timing of other behaviors was not independently associated with BMI. The latent class analysis identified 2 distinct groups related to behavioral timing, reflecting an "early bird" and "night owl" phenotype. These phenotypes were not associated with BMI (P > .05). CONCLUSION: Timing of exposures to light, meals, sleep, and physical activity were not strongly associated with BMI in this sample.

"Let's talk about sleep": a qualitative examination of levers for promoting healthy sleep among sleep-deprived vulnerable adolescents.

OBJECTIVE: Deficient sleep is highly prevalent in disadvantaged adolescents and contributes to a range of adverse health and behavioral outcomes. We examined mediating mechanisms and strategies that adolescents adopt to improve sleep, and possible levers for promoting sleep in this population. METHODS: We conducted three focus groups (N = 27 total, age 14-18 years) in adolescents living in low- and middle-income racially/ethnically diverse neighborhoods of Boston, Massachusetts. Participants completed a survey on their sleep and health habits prior to the moderator-led discussions. Discussions were audio-recorded, transcribed, and thematically analyzed. RESULTS: The study population did not meet the minimum sleep recommendations, and we found a high prevalence of "social jet-lag." We also identified a disconnect between the acknowledgment of the importance of sleep and actual behavior, especially for electronic use. Phone use and screen time were the most commonly cited barriers to a good night's sleep, along with caffeine consumption, which was also high in this sample. There was also a general lack of awareness of sleep hygiene practices and recommendations. Participants reported regulating food intake and physical activity, using allopathic sleep aids, creating a comfortable sleeping environment, and a routine as some strategies to improve sleep. CONCLUSION: Results from this study suggest facilitating the linkage between participant-generated mediating factors and strategies for better-designed interventions. These include making the negative impact of sleep on health more explicit, improving youth awareness about sleep hygiene, targeting caffeine consumption and electronic use, and introducing sleep recommendations through appropriate and effective channels.