Physical activity and objectively assessed sleep in 6-month-old infants in Taiwan

Accelerometer Thresholds for Estimating Physical Activity Intensity Levels in Infants: A Preliminary Study

Lack of physical activity (PA) at a young age can result in health issues. Thus, monitoring PA is important. Wearable accelerometers are the preferred tool to monitor PA in children. Validated thresholds are used to classify activity intensity levels, e.g., sedentary, light, and moderate-to-vigorous, in ambulatory children. No previous work has developed accelerometer thresholds for infancy (pre-ambulatory children). Therefore, this work aims to develop accelerometer thresholds for PA intensity levels in pre-ambulatory infants. Infants (n = 10) were placed in a supine position and allowed free movement. Their movements were synchronously captured using video cameras and accelerometers worn on each ankle. The video data were labeled by activity intensity level (sedentary, light, and moderate-to-vigorous) in two-second epochs using observational rating (gold standard). Accelerometer thresholds were developed for acceleration and jerk using two optimization approaches. Four sets of thresholds were developed for dual (two ankles) and for single-worn (one ankle) accelerometers. Of these, for a typical use case, we recommend using acceleration-based thresholds of 1.00 m/s to distinguish sedentary and light activity and 2.60 m/s to distinguish light and moderate-to-vigorous activity. Acceleration and jerk are both suitable for measuring PA.

Sleep initiation patterns and sleep quality among toddlers in the southeast of China: initial study results

BACKGROUND

A large number of psychological consequences including sleep health emerged during the 2019 Coronavirus disease (COVID-19) pandemic. Sleep patterns in toddlers are vulnerable to negative environmental exposures, however, very few studies on this topic have been published so far.

OBJECTIVES

In this paper, we aimed to investigate the sleep patterns and associated factors in toddlers from China confined at home in the context of COVID-19 pandemic.

METHODS

From April to November 2021, a convenience sample of 493 parents of young children aged (12-35 months) were surveyed from Fuzhou, Sanming, Quanzhou, Nanping, and Longyan cities in the Fujian Province, China. A cross-sectional survey was conducted via Electronic questionnaires to collect parent and child social-demographic characteristics. The Brief Infant Sleep Questionnaire (BISQ) was used to collect data on sleep practices, sleep duration and patterns, as well as the number of nocturnal awaking .

RESULTS

The mean age of toddlers was 2.11 years old, and 52.54% (259/493) were males. Among the 493 toddlers' sleep patterns, 331(67.1%) initiated sleep accompanied by parents, 67(13.6%) slept independently, 59 (12.0%) were breast fed/bottle fed to initiate sleep, 27 (5.5%) were held and 9 (1.8%) rocked. The clear longitudinal association between the duration of night-time sleep, the frequency of nighttime awakenings, and various sleep patterns remains clear (p < 0.05). Multiple linear regression analysis indicated that sleep initiation with bottle-feeding/breast-feeding and rocked significantly increased the frequency of nighttime awakenings and reduced the duration of nighttime sleep (p < 0.05), as held was dramatically only for increasing the number of nighttime awakenings (p < 0.05). Multi-variate logistic regression analysis demonstrated that toddlers with severe sleep difficulties had a higher probability of being rocked to initiate sleep (p < 0.05). Conversely, young children with minor sleep problems were more apt to be in bed alone to initiate sleep (p < 0.05).

CONCLUSIONS

During the COVID-19 pandemic, most infants and toddlers initiated sleep accompanied by parents and tend to have electronic media exposure before bedtime. Increased waking at night may be associated with sleep initiation with breast-feeding/bottle-feeding. Therefore, pediatric practitioners in primary community hospitals should pay attention to the education and promotion of sleep hygiene and parenting knowledge of young children to avoid the formation of poor sleep hygiene habits.

Infant motor development predicts the dynamics of movement during sleep

The characteristics of infant sleep change over the first year. Generally, infants wake and move less at night as they grow older. However, acquisition of new motor skills leads to temporary increases in night waking and movement at night. Indeed, sleep-dependent movement at night is important for sensorimotor development. Nevertheless, little is known about how movement during sleep changes as infants accrue locomotor experience. The current study investigated whether infant sleep and movement during sleep were predicted by infants' walking experience. Seventy-eight infants wore an actigraph to measure physical activity during sleep. Parents reported when their infants first walked across a room >10 feet without stopping or falling. Infants in the midst of walking skill acquisition had worse sleep than an age-group estimate. Infants with more walk experience had more temporally sporadic movement during sleep and a steeper hourly increase in physical activity over the course of the night. Ongoing motor skill consolidation changes the characteristics of movement during sleep and may alter sleep state-dependent memory consolidation. We propose a model whereby changes in gross motor activity during night sleep reflect movement-dependent consolidation.

Behavioral, Environmental, and Demographic Factors Associated with Objectively Measured Physical Activity in Infants

Background: To describe objectively measured physical activity (PA) in infants, and to identify demographic, behavioral, and environmental factors associated with infants' PA. Methods: Participants were 6-7-month-old infants and their mothers (N = 143 dyads) from two Southeastern US counties. Infant measures included PA assessed by accelerometers at ankle and waist sites, motor developmental status (i.e., stationary and locomotion), and anthropometric characteristics (i.e., height and weight). Mothers provided information on home environment, child care settings, and family demographic factors. PA levels were compared across demographic subgroups. Correlation coefficients described associations between PA and continuous variables, including motor developmental status and anthropometric characteristics. Multiple linear regression analyses examined factors found to be independently associated with PA. Results: Infants' PA counts were greater at the ankle (77,700 counts/hr) vs. the waist site (32,500 counts/hr). In univariate analyses, a diverse set of environmental, behavioral, and infant-level demographic factors were found to be significantly associated with PA at the ankle site. Multivariate analyses indicated that more advanced motor development status (B = 666.3 ± 329.8, p < 0.05), attendance at home child care settings (B = -13,724.4 ± 5083.9, p < 0.05), greater exposure to tummy time (B = 213.5 ± 79.9, p < 0.05), and white racial/ethnic composition (B = -19,953.4 ± 5888.5, p < 0.01) were independently, associated with infants' PA. Conclusions: In 6-7-month-old infants, objectively measured PA was found to be associated with motor developmental status and physical and social environmental factors, including both demographic moderators and factors that are influenced by parents and caregivers. Longitudinal studies are needed to determine if these relationships persist or change as infants develop.

Relationships between screen viewing and sleep quality for infants and toddlers in China: A cross-sectional study

AIM

Currently young children have more opportunity to access all kinds of media, while their sleep duration has been steadily decreasing. However, little is known about the relationships between screen viewing and sleep quality, and the reasons of screen viewing for children under three years old in China. This study aimed to describe the relationships between screen viewing and sleep quality of infants and toddlers in mainland China.

METHODS

A cross-sectional study was conducted. Eight hundred twenty-seven children were recruited at a health care unit from a university affiliated hospital in China, and the questionnaires were completed by their parents. An extended Brief Infant Sleep Questionnaire and a Screen Viewing Questionnaire were used to collect information on children's sleep quality and screen viewing. Multivariate linear regression models were used to assess the relationships between screen viewing and sleep quality among infants and toddlers, adjusted for sociodemographic variables.

RESULTS

Of the 827 children, 26.9% of the infants and 61.4% of the toddlers did not comply with the World Health Organization (WHO) guideline on screen time. Even after adjusting for the sociodemographic covariates for both infants and toddlers, negative relationships between screen time and total sleep time (P < 0.001), and screen time and nighttime sleep (P < 0.001) existed. TV viewing time was negatively related to infants' total sleep time (β = -0.15, P < 0.001) and toddlers' nighttime sleep (β = -0.1, P < 0.05). Smartphone viewing time was negatively related to toddlers' total sleep time (β = -0.12, P < 0.05) and daytime sleep (β = -0.22, P < 0.05). Parents who offered screen media for children when they needed to do house chores were more likely to report that their children had less total sleep time (β = -0.1, P < 0.05) and shorter longest sleep episode (β = -0.1, P < 0.05).

CONCLUSION

The majority of toddlers did not meet the WHO guidelines on screen time in China. Screen time was negatively related to total sleep time and nighttime sleep among infants and toddlers. Practical strategies, such as education programs on children's screen viewing, more outdoor exercises and indoor parent-child activities, providing other educational materials instead of screening, early sleep, restricted use of TVs and smartphones, and screen co-viewing, are needed to improve young children's sleep quality and promote their development.

A Systematic Review of the Relationships Between Physical Activity and Sleep in Early Childhood

The aim of this systematic review was to examine the associations between physical activity and sleep in children aged less than 6 years. Articles were included if participants were primarily aged less than 6 years and study designs were observational or experimental. Study characteristics were extracted, and the Grading Recommendations Assessment, Development and Evaluation framework was used to assess study quality. Thirty-six studies (16 sleep, 16 physical activity, and three fitness outcomes) from 18 countries reported in 29 articles were included. The majority of sleep and physical activity outcome studies reported mixed effects with very low to low quality of evidence. Fitness outcome studies were limited, and therefore, evidence was insufficient. The high prevalence of mixed and null results could be related to study limitations. Importantly, this review points to the critical need for higher quality studies of sleep and physical activity in young children, which would support health recommendations and intervention strategies for healthier child development.

Nighttime sleep and physical activity in 6-7 month-old infants

This study examined associations between objectively-measured nighttime sleep duration and physical activity in a sample of 6-7 month-old infants (N=93). The study also investigated relationships between infant sleep and demographic and environmental characteristics. Cross-sectional relationships were assessed using linear regression analyses. Nighttime sleep duration was positively associated with physical activity levels. Nighttime sleep duration was greater when infants had a consistent bedtime, slept in a separate room, were male, and had mothers who reported having a college education or greater. These findings can inform the development of interventions that aim to improve infant sleep.

Measurement of screen time among young children aged 0-6 years: A systematic review

The impact of screen-based devices on children's health and development cannot be properly understood without valid and reliable tools that measure screen time within the evolving digital landscape. This review aimed to summarize characteristics of measurement tools used to assess screen time in young children; evaluate reporting of psychometric properties; and examine time trends related to measurement and reporting of screen time. A systematic review of articles published in English across three databases from January 2009 to April 2020 was undertaken using PROSPERO protocol (registration: CRD42019132599) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Included articles measured screen time as outcome, exposure, or confounder in children 0-6 years. The search identified 35,868 records, 1035 full-text articles were screened for eligibility, and 622 met inclusion criteria. Most measures (60%) consisted of one to three items and assessed duration of screen time on a usual day. Few measures assessed content (11%) or coviewing (7%). Only 40% of articles provided a citation for the measure, and only 69 (11%) reported psychometric properties-reliability n = 58, validity n = 19, reliability and validity n = 8. Between 2009 and 2019, the number of published articles increased from 28 to 71. From 2015, there was a notable increase in the proportion of articles published each year that assessed exposure to mobile devices in addition to television. The increasing number of published articles reflects increasing interest in screen time exposure among young children. Measures of screen time have generally evolved to reflect children's contemporary digital landscape; however, the psychometric properties of measurement tools are rarely reported. There is a need for improved measures and reporting to capture the complexity of children's screen time exposures.

Infant media use: A harm reduction approach

There are a myriad of potentially harmful developmental outcomes associated with infant digital media use. Studies revealing risk associated with early media use have informed the current American Academy of Pediatrics (AAP) recommendations that discourage most digital media use among children under 18 months of age. Recent research advances, however, suggest potential benefits of technology engagement in this age group. Additionally, surveys of parents reveal that most infants engage with digital media for at least 30 min a day, exceeding the AAP recommendations. In response to these discoveries and cultural trends, some scholars have made compelling cases to adapt the AAP guidelines for infants. A helpful model for developing infant digital media use guidelines for families may be the harm reduction approach. The intent of this review is to suggest adaptations to the AAP guidelines for infant media engagement using a harm reduction framework. This review describes the challenge of restrictive guidelines, briefly summarizes the harm reduction approach, provides a review of risks and benefits associated with infant media use in each developmental domain (physical, cognitive, and socioemotional), summarizes correlates of infant screen media use, and examines intervention strategies for reducing screen time. The paper concludes with examples of possible adaptations to current AAP infant media use recommendations using harm reduction and bioecological frameworks.

Studying caregiver-infant co-regulation in dynamic, diverse cultural contexts: A call to action

Caregivers and infants co-regulate their physiology, emotions, and behavior in a way that is dynamically responsive to each other and the contexts in which they live. This paper is an introduction and call to action for researchers interested in understanding how to study caregiver-infant interactions in the home and diverse cultural contexts, including marginalized communities. We argue that research will be more valid, culturally relevant, and tapped-in to the daily lives of caregivers and infants if there is partnership and collaboration with the caregivers in the design of the questions, data collection and analysis, and distribution of the findings. We recommend dynamically assessing emotions, behaviors, and physiology using repeated sampling methods including ecological momentary assessments (EMA), salivary bioscience, and actigraphy. We aim to extend current practices of studying caregiver-infant co-regulation by measuring fluctuations of daily life and considering sociocultural factors that shape naturalistic caregiver-infant interactions. Using methodological advancements and community-based participatory research approaches can enable developmental scientists to measure life as it is actually lived.

Actigraphy in sleep research with infants and young children: Current practices and future benefits of standardized reporting

Actigraphy is a cost-efficient method to estimate sleep-wake patterns over long periods in natural settings. However, the lack of methodological standards in actigraphy research complicates the generalization of outcomes. A rapidly growing methodological diversity is visible in the field, which increasingly necessitates the detailed reporting of methodology. We address this problem and evaluate the current state of the art and recent methodological developments in actigraphy reporting with a special focus on infants and young children. Through a systematic literature search on PubMed (keywords: sleep, actigraphy, child *, preschool, children, infant), we identified 126 recent articles (published since 2012), which were classified and evaluated for reporting of actigraphy. Results show that all studies report on the number of days/nights the actigraph was worn. Reporting was good with respect to device model, placement and sleep diary, whereas reporting was worse for epoch length, algorithm, artefact identification, data loss and definition of variables. In the studies with infants only (n = 58), the majority of articles (62.1%) reported a recording of actigraphy that was continuous across 24 hr. Of these, 23 articles (63.9%) analysed the continuous 24-hr data and merely a fifth used actigraphy to quantify daytime sleep. In comparison with an evaluation in 2012, we observed small improvements in reporting of actigraphy methodology. We propose stricter adherence to standards in reporting methodology in order to streamline actigraphy research with infants and young children, to improve comparability and to facilitate big data ventures in the sleep community.

Correlates of Sleep Duration in Early Childhood: A Systematic Review

OBJECTIVE

This systematic review aimed to summarize correlates of sleep duration in children under 5 years of age.

METHODS

Six electronic databases (PubMed, PsycINFO, MEDLINE, CINAHL, SPORTDiscus, and Scopus) were searched from inception to May 2019. Observational studies and intervention studies reporting cross-sectional results from baseline data were considered. Data were extracted using a predesigned form and potential correlates were categorized following a sociological framework.

RESULTS

One-hundred and sixteen studies, representing 329,166 children, met the inclusion criteria, with a high risk of bias in 62 included studies. A total of 83 correlates of sleep duration were identified. Among the associations studied four or more times, correlates of nap duration were child's age and nighttime sleep onset/bedtime; correlates of nighttime sleep duration were household income, parent marital status, parental adiposity level, nighttime sleep duration at younger age, nighttime sleep onset/bedtime, nighttime sleep wakeup time, and frequency of current bedtime routine; correlate of total sleep duration was screen time.

CONCLUSIONS

Young children from low-income households, single families, or having overweight parents may be at risk for short sleep duration. Promoting healthy sleep duration from an early age appears essential. Effective practices may include encouraging an earlier bedtime, limiting screen time, and establishing a regular bedtime routine. The absence of consistent evidence in the psychological, cognitive, and emotional domain as well as the physical environmental domain warrants further research.

Cross-Sectional Associations of 24-Hour Sedentary Time, Physical Activity, and Sleep Duration Compositions with Sleep Quality and Habits in Preschoolers

Although some studies indicate physical activity and sleep quality are positively associated in children, most reports examined physical activity independent of other 24-h behaviors and focused on older children. The aim of this cross-sectional study was to examine the predicted changes in sleep efficiency and habits when reallocating time between movement behaviors using compositional isotemporal substitution in preschool-aged children. Accelerometers were worn by 288 participants (51.6 ± 9.5 months) for up to 16 days. Sleep outcomes included sleep efficiency, nap frequency, sleep disturbances, and bedtime resistance. Compositional isotemporal substitution analyses demonstrated that the combined effect of 24-h movement behaviors was associated with sleep efficiency (p < 0.001) and nap frequency (p < 0.003). When sleep increased by 30 min at the expense of stationary time or light physical activity, estimates of sleep efficiency and bedtime resistance decreased while nap frequency increased. When stationary time increased by 30 min from moderate to vigorous physical activity, estimated sleep efficiency increased and sleep disturbances decreased. Although this study presents preliminary evidence that 24-h movement behavior compositions in early childhood are associated with sleep quality and nap frequency, estimated effects from theoretical time reallocations across sleep outcomes were mixed.

Infants' and toddlers' physical activity and sedentary time as measured by accelerometry: a systematic review and meta-analysis

BACKGROUND

Early experiences in physical activity (PA) are important to shape healthy movement behaviours long-term; as such, it is critical that PA is promoted from infancy, and that detrimental behaviours (e.g., prolonged sedentary time [ST]) are minimized. The purpose of this systematic review and meta-analysis was to examine infants' and toddlers' movement behaviours across daytime hours.

METHODS

Seven online databases were searched for terms related to infants (< 12 months), toddlers (12-35.9 months), PA, ST, and accelerometry. Two independent reviewers examined 4873 articles for peer-reviewed original research, published in English, that assessed infants' (counts/min) and/or toddlers' PA or ST (min/day) using accelerometry across daytime hours. Infants' mean PA level (counts/min) was averaged across studies, and ranges were produced. Estimates of toddlers' movement behaviours were aggregated meta-analytically to produce average daily rates, and accelerometer placement, cut-point validity, device type, and epoch length were tested as a moderating variables.

RESULTS

Twenty-four studies from 16 countries (published 2011-2019), representing 3699 participants, were included in the systematic review. Five studies reported on infants' PA, which ranged from 78.2 to 2580.5 cpm. Across 20 studies, toddlers' total PA, light PA, moderate-to vigorous-intensity PA, and ST ranged from 72.9 to 636.5, 48.5 to 582.4, 6.5 to 89.9, and 172.7 to 545.0 min/day, respectively. After taking into account accelerometer placement, cut-point validity, device type, and epoch length, we found that toddlers engaged in 246.19 min/day (SE = 28.50; 95% CI: 190.34, 302.04) of total PA, 194.10 min/day (SE = 28.76; 95% CI: 137.73, 250.47) of light PA, and 60.16 min/day (SE = 5.88; 95% CI: 48.64, 71.69) of moderate-to vigorous-intensity PA. Toddlers engaged in 337.04 min/day (SE = 32.67; 95% CI: 273.01, 401.07) of ST.

CONCLUSIONS

With limited studies conducted in infants (n = 5), PA estimates are inconclusive and largely heterogeneous. Overall, toddlers tend to exceed the total PA recommendation of 180 min/day; however, very little of this time is spent at higher movement intensities. Even with high PA rates, toddlers still engage in substantial ST. More consistent and valid measurement protocols are needed to improve comparability across studies.

Associations of screen time, sedentary time and physical activity with sleep in under 5s: A systematic review and meta-analysis

Sleep is crucial to children's health and development. Reduced physical activity and increased screen time adversely impact older children's sleep, but little is known about these associations in children under 5 y. This systematic review examined the association between screen time/movement behaviors (sedentary behavior, physical activity) and sleep outcomes in infants (0-1 y); toddlers (1-2 y); and preschoolers (3-4 y). Evidence was selected according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and synthesized using vote counting based on the direction of association. Quality assessment and a Grading of Recommendations, Assessment, Development and Evaluation was performed, stratified according to child age, exposure and outcome measure. Thirty-one papers were included. Results indicate that screen time is associated with poorer sleep outcomes in infants, toddlers and preschoolers. Meta-analysis confirmed these unfavorable associations in infants and toddlers but not preschoolers. For movement behaviors results were mixed, though physical activity and outdoor play in particular were favorably associated with most sleep outcomes in toddlers and preschoolers. Overall, quality of evidence was very low, with strongest evidence for daily/evening screen time use in toddlers and preschoolers. Although high-quality experimental evidence is required, our findings should prompt parents, clinicians and educators to encourage sleep-promoting behaviors (e.g., less evening screen time) in the under 5s.