Child Health CheckPoint Research Articles

Time use and dimensions of healthy sleep: A cross-sectional study of Australian children and adults

BackgroundSleep is increasingly recognized as a multidimensional construct that occurs within the 24-hour day. Despite advances in our understanding, studies continue to consider the relationship between sleep, sedentary time and physical activity separately, and not as part of the 24-hour day. AimsTo determine the association between the 24-hour activity composition and dimensions of healthy sleep. MethodsThis study examined data on 1168 children (mean age 12years; 49% female) and 1360 adults (mean age 44years; 87% female) collected as part of the Child Health CheckPoint study. Participants were asked to wear a GENEActiv monitor (Activinsights, Cambs, UK) on their nondominant wrist for eight consecutive days to measure 24-hour time-use. Compositional data analysis was used to examine the association between time use (actigraphy-derived sleep duration, sedentary time, light physical activity and moderate-vigorous physical activity) and dimensions of healthy sleep. Healthy sleep was conceptualized in terms of continuity/efficiency, timing, alertness/sleepiness, satisfaction/quality, and regularity. Time allocations were also examined. ResultsThe 24-hour activity composition was significantly associated with all objectively measured and self-report dimensions of healthy sleep in both children and adults. Allocating more time to sleep was associated with earlier sleep onsets, later sleep offsets, less efficient and more consistent sleep patterns for both children and adults. ConclusionThis study highlights the integral relationship between daily activities and dimensions of sleep. Considering sleep within the 24-hour day activity composition framework may help inform lifestyle decisions to improve sleep health.

The Association Between Socioeconomic Status and Use of Time in Australian Children and Adolescents

PurposeThere are well-known socioeconomic status (SES) gradients in children and adolescents' health which may be associated with time use. Our aim was to evaluate the association between Australian children's 24-hour time use and SES using four separate surveys from 2005 to 2021. MethodsTime use was assessed in 4526 8-19-year-olds from the 2005 Health of Young Victorians, 2007 National Children's Nutrition and Physical Activity, 2015 Child Health CheckPoint, and 2019-21 Life on Holidays study. Each survey used the same reliable, valid, 24-hour recall instrument. SES was quantified using tertiles of household income, education, and postcode-level measures. Compositional data analysis was used to compare 24-hour time use between SES categories, adjusting for age, sex, and puberty. ResultsTime-use compositions differed significantly by SES in each survey. Relative to the lowest SES, children from the highest SES accumulated on average 31 min/day more School-related time, 6 min/day more Passive Transport and 6 min/day more Self-care. Conversely, they accumulated 30 min/day less Screen Time (which included computer time), 11 min/day less sleep, and spent 7 min/day less in Domestic/Social activities. There were only small differences in Quiet Time and Physical Activity. DiscussionSES-related differences in time use were robust across ages 8-19, a 16-year timespan, diverse Australian geographical regions, and using different SES metrics. The exchange of about 30 min/day between School-related activities and Screen Time amounts to >180 hours extra exposure to School-related activities annually in the highest SES category relative to the lowest, equivalent to >6 weeks of school time per year.

Branched-chain amino acids and sleep: a population-derived study of Australian children aged 11-12 years and their parents.

Micronutrients, particularly amino acids, are thought to play an important role in sleep regulation and maintenance. While tryptophan is a known predictor of sleep, less is known about branched-chain amino acids (BCAAs), which compete with tryptophan for transport across the blood-brain barrier. The aim of this study was to determine the association between BCAAs and actigraphy-derived sleep duration, timing and efficiency, and self-reported trouble sleeping. This study examined data on children and adults collected as part of the Child Health CheckPoint study. Linear mixed models, adjusted for geographic clustering, were used to determine the association between BCAAs and sleep characteristics. Complete-case analysis was conducted for 741 children aged 11-12 years old (51% females) and 941parents (87% mothers). While BCAAs were significantly associated with children's sleep duration, timing and self-reported trouble sleeping, no associations were observed in adults, in fully adjusted models. In children, higher levels of BCAAs are associated with shorter sleep duration, delayed sleep timing, and more frequent reports of trouble sleeping.

Fat-Soluble Vitamers: Parent-Child Concordance and Population Epidemiology in the Longitudinal Study of Australian Children

Fat-soluble vitamers (FSV) are a class of diverse organic substances important in a wide range of biological processes, including immune function, vision, bone health, and coagulation. Profiling FSV in parents and children enables insights into gene-environment contributions to their circulating levels, but no studies have reported on the population epidemiology of FSV in these groups as of yet. In this study, we report distributions of FSV, their parent-child concordance and variation by key characteristics for 2490 children (aged 11-12 years) and adults (aged 28-71 years) in the Child Health CheckPoint of the Longitudinal Study of Australian Children. Ten A, D, E and K vitamers were quantified using a novel automated LC-MS/MS method. All three K vitamers (i.e., K1, MK-4, MK-7) and 1-α-25(OH)2D3 were below the instrument detection limit and were removed from the present analysis. We observed a strong vitamer-specific parent-child concordance for the six quantifiable A, D and E FSVs. FSV concentrations all varied by age, BMI, and sex. We provide the first cross-sectional population values for multiple FSV. Future studies could examine relative genetic vs. environmental determinants of FSV, how FSV values change longitudinally, and how they contribute to future health and disease.

Multidimensional Sleep and Cardiometabolic Risk Factors for Type 2 Diabetes: Examining Self-Report and Objective Dimensions of Sleep.

The purpose of the study was to determine the association between objective and self-report measures of sleep and cardiometabolic risk factors for type 2 diabetes. This study examines data on Australian adults, collected as part of the Child Health CheckPoint study. Sleep was examined in terms of actigraphy-derived sleep duration, timing, efficiency and variability; and self-report trouble sleeping. Cardiometabolic risk factors for type 2 diabetes were examined in terms of body mass index and biomarkers of inflammation and dyslipidemia. Generalized estimating equations, adjusted for geographic clustering, were used to determine the association between measures of sleep and cardiometabolic risk factors. Complete case analysis was conducted for 1017 parents (87% mothers). Both objective and self-report measures of sleep were significantly but weakly associated with cardiometabolic risk factors. Both objective and self-report measures of sleep are significantly associated with cardiometabolic risk factors for type 2 diabetes. Self-report troubled sleep is associated with poorer cardiometabolic health, independent of actigraphy-derived sleep parameters.

Your best day: An interactive app to translate how time reallocations within a 24-hour day are associated with health measures.

Reallocations of time between daily activities such as sleep, sedentary behavior and physical activity are differentially associated with markers of physical, mental and social health. An individual's most desirable allocation of time may differ depending on which outcomes they value most, with these outcomes potentially competing with each other for reallocations. We aimed to develop an interactive app that translates how self-selected time reallocations are associated with multiple health measures. We used data from the Australian Child Health CheckPoint study (n = 1685, 48% female, 11-12 y), with time spent in daily activities derived from a validated 24-h recall instrument, %body fat from bioelectric impedance, psychosocial health from the Pediatric Quality of Life Inventory and academic performance (writing) from national standardized tests. We created a user-interface to the compositional isotemporal substitution model with interactive sliders that can be manipulated to self-select time reallocations between activities. The time-use composition was significantly associated with body fat percentage (F = 2.66, P < .001), psychosocial health (F = 4.02, P < .001), and academic performance (F = 2.76, P < .001). Dragging the sliders on the app shows how self-selected time reallocations are associated with the health measures. For example, reallocating 60 minutes from screen time to physical activity was associated with -0.8 [95% CI -1.0 to -0.5] %body fat, +1.9 [1.4 to 2.5] psychosocial score and +4.5 [1.8 to 7.2] academic performance. Our app allows the health associations of time reallocations to be compared against each other. Interactive interfaces provide flexibility in selecting which time reallocations to investigate, and may transform how research findings are disseminated.

Perceived green space quality, child biomarkers and health-related outcomes: A longitudinal study

Accumulating exposure to quality green space over time is posited to influence child health, yet longitudinal studies are scarce. This study aimed to examine the associations between trajectories of perceived green space quality and child health-related outcomes. We used data from 1874 childrenin the B-cohort of the Longitudinal Study of Australian Children who participated in the Child Health Checkpoint module at 11–12 years. Data on caregiver perceived green space quality measured biennially was assessed using discrete trajectory mixture models to group children by contrasting distributions in green space quality over time. Examination of associations between trajectory groups of perceived green space quality and child biomarkers (i.e., albumin-to-creatinine ratio, total, cholesterol, total triglycerides, and glucose), physical health and behavioural assessments (i.e., anthropometric measurements, blood pressure, sedentary behaviour, physical activity, sleep, aerobic work capacity, and general wellbeing), and health care use were assessed using multilevel models, adjusted for sociodemographic variables. Four perceived green space quality trajectories were identified: “decreasing quality from high to moderate”; “increasing quality from low to high”; “consistently high quality”; “consistently low quality”. Compared with consistently low levels of quality green space, adjusted models indicated consistently high-quality green space was associated with lower total triglycerides (β −0.13; 95%CI -0.25, −0.01). Lower odds of hospital admission was observed among children who accumulated quality green space over time (OR 0.45; 95%CI 0.23, 0.87). These associations were observed in boys only in sex-stratified analyses. Moreover, boys accumulating quality green space through time tended to have lower diastolic blood pressure (β −2.76; 95%CI -5.17, −0.35) and girls who experienced loss in quality green space tended to have a higher percentage of body fat (β 2.81; 95%CI 0.43, 5.20). Accumulating quality green space over time is important for various aspects of child health, with contrasting benefits by sex.

Does inflammation mediate the association between obesity and hearing status in mid-childhood and mid-life?

Obesity is characterized by heightened inflammation, and both phenotypes are associated with hearing loss. We aimed to determine if inflammation mediates the associations between obesity and hearing ability in mid-childhood and mid-life. Participants: 1165 11- to 12-year-old children and 1316 parents in the population-based cross-sectional Child Health CheckPoint within the Longitudinal Study of Australian Children. Adiposity measures: Body mass index (BMI) classified as normal, overweight and obesity; waist-to-height ratio (WHtR) classified as <0.5 and ≥0.5; fat mass index. Inflammatory biomarkers: Serum glycoprotein A (GlycA); high-sensitivity C-reactive protein (hsCRP). Audiometry: Composite high Fletcher Index (mean threshold of 1, 2, 4 kHz) in the better ear. Causal mediation analysis decomposed a 'total effect' (obesity on hearing status) into 'indirect' effect via a mediator (eg GlycA, hsCRP) and 'direct' effect via other pathways, adjusting for age, sex and socioeconomic position. Compared to adults with BMI within the normal range, those with obesity had hearing thresholds 1.9 dB HL (95% CI 1.0-2.8) higher on the high Fletcher Index; 40% of the total effect was mediated via GlycA (indirect effect: 0.8 dB HL, 95% CI 0.1-1.4). Children with obesity had hearing thresholds 1.3 dB HL (95% CI 0.2-2.5) higher than those with normal BMI, of which 67% (indirect effect: 0.9 dB HL, 95% CI 0.4-1.4) was mediated via GlycA. Similar mediation effects were noted using other adiposity measures. Similar but less marked mediation effects were observed when hsCRP was used as the inflammatory biomarker (6-23% in adults and 23-33% in children). Inflammation may play an important mediating role in the modest hearing reductions associated with obesity, particularly in children. These findings offer insights into possible mechanisms and early prevention strategies for hearing loss.

Goldilocks Days: optimising children’s time use for health and well-being

BackgroundOne size rarely fits all in population health. Differing outcomes may compete for best allocations of time. Among children aged 11–12 years, we aimed to (1) describe optimal 24-hour time...

Oral health: Epidemiology and concordance in Australian children and parents.

Studying parent-child pair health provides the opportunity to identify risk factors and opportunities for oral health prevention and intervention focusing on the family context. The aim of this study was to describe the oral health of children aged 11-12years and their parents in a national sample of parent-child dyads in Australia. The Child Health CheckPoint is a study of 11 to 12-year-old children and one parent nested within the Longitudinal Study of Australian Children, a nationally representative cohort study. In 2015-16, the study collected two-dimensional photographic intra-oral images and was scored using visual assessments of the teeth, oral hygiene and malocclusion. Of the 1874 CheckPoint families, 1396 biological parent-child pairs had at least one oral health measure recorded. Over two-thirds of children had moderate to severe gingival inflammation (69.7%, 95%CI 64.7-74.9). Parents had a lower proportion of poor oral hygiene (2.1%, 95% CI 1.4-3.0) than children (13.0%, 95% CI 11.3-14.9). High concordance was seen in the Modified Gingival Index correlation coefficient 0.49 (95%CI 0.44-0.53). The high concordance in gingival health between child-parent pairs supports the familial and behavioural links established in previous studies. Children had poorer oral hygiene but fewer visible dental caries lesions than their parents. As dental caries is a chronic and cumulative disease, preventive interventions targeting children's oral hygiene are needed.

Diet quality trajectories and cardiovascular phenotypes/metabolic syndrome risk by 11-12 years.

To investigate associations between early-life diet trajectories and preclinical cardiovascular phenotypes and metabolic risk by age 12 years. Participants were 1861 children (51% male) from the Longitudinal Study of Australian Children. At five biennial waves from 2-3 to 10-11 years: Every 2 years from 2006 to 2014, diet quality scores were collected from brief 24-h parent/self-reported dietary recalls and then classified using group-based trajectory modeling as 'never healthy' (7%), 'becoming less healthy' (17%), 'moderately healthy' (21%), and 'always healthy' (56%). At 11-12 years: During children's physical health Child Health CheckPoint (2015-2016), we measured cardiovascular functional (resting heart rate, blood pressure, pulse wave velocity, carotid elasticity/distensibility) and structural (carotid intima-media thickness, retinal microvasculature) phenotypes, and metabolic risk score (composite of body mass index z-score, systolic blood pressure, high-density lipoproteins cholesterol, triglycerides, and glucose). Associations were estimated using linear regression models (n = 1100-1800) adjusted for age, sex, and socioeconomic position. Compared to 'always healthy', the 'never healthy' trajectory had higher resting heart rate (2.6 bpm, 95% CI 0.4, 4.7) and metabolic risk score (0.23, 95% CI 0.01, 0.45), and lower arterial elasticity (-0.3% per 10 mmHg, 95% CI -0.6, -0.1) and distensibility (-1.2%, 95% CI -1.9, -0.5) (all effect sizes 0.3-0.4). Heart rate, distensibility, and diastolic blood pressure were progressively poorer for less healthy diet trajectories (linear trends p ≤ 0.02). Effects for systolic blood pressure, pulse wave velocity, and structural phenotypes were less evident. Children following the least healthy diet trajectory had poorer functional cardiovascular phenotypes and metabolic syndrome risk, including higher resting heart rate, one of the strongest precursors of all-cause mortality. Structural phenotypes were not associated with diet trajectories, suggesting the window to prevent permanent changes remains open to at least late childhood.

Time Equivalency and Child Adiposity: The Biggest Bang for the Buck.

* Abbreviations: HRQoL — : health-related quality of life MVPA — : moderate-vigorous physical activity The public health, medical, and research community has increased focus on childhood obesity over the past few decades and for good reason. Obesity prevalence is at an all-time high,1 and rates of severe obesity continue to increase.2 Activity, both sedentary and physical, are key contributors to the development and treatment of obesity.3–5 Increasing physical activity while decreasing sedentary activity is an obvious goal in improving the weight and health of children. Unfortunately, the majority of children in the United States are not receiving the recommended amounts of physical activity and surpassing suggested limits on sedentary activity.6 Because there are finite hours in a day, increasing time spent on 1 activity will require doing less of another (ie, replacing one activity with another). In the case of activity, it is assumed that increased time spent engaged in physical activity is always beneficial, without the recognition that it may detract from other important life and health components (eg, sleep and school work). Exploring how individuals allocate their time may provide insight into how one can increase time spent in a beneficial behavior (eg, exercise), without stealing that time from an activity that is also beneficial (eg, sleep). In their study, Ng et al7 approached this topic through the lens of time and in relation … Address correspondence to Michelle I. Cardel, PhD, MS, RD, Department of Health Outcomes and Biomedical Informatics, College of Medicine, University of Florida, 2197 Mowry Rd, Gainesville, FL 32607. E-mail: mcardel{at}ufl.edu

Equivalence Curves for Healthy Lifestyle Choices.

Understanding equivalence of time-use trade-offs may inform tailored lifestyle choices. We explored which time reallocations were associated with equivalent changes in children's health outcomes. Participants were from the cross-sectional Child Health CheckPoint Study (N = 1179; 11-12 years; 50% boys) nested within the population-based Longitudinal Study of Australian Children. Outcomes were adiposity (bioelectrical impedance analysis, BMI and waist girth), self-reported health-related quality of life (HRQoL; Pediatric Quality of Life Inventory), and academic achievement (standardized national tests). Participants' 24-hour time use (sleep, sedentary behavior, light physical activity, and moderate-to-vigorous physical activity [MVPA]) from 8-day 24-hour accelerometry was regressed against outcomes by using compositional log-ratio linear regression models. Children with lower adiposity and higher HRQoL had more MVPA (both P ≤ .001) and sleep (P = .001; P < .02), and less sedentary time (both P < .001) and light physical activity (adiposity only; P = .03), each relative to remaining activities. Children with better academic achievement had less light physical activity, relative to remaining activities (P = .003). A 0.1 standardized decrease in adiposity was associated with either 52 minutes more sleep, 56 minutes less sedentary time, 65 minutes less light physical activity, or 17 minutes more MVPA. A 0.1 standardized increase in HRQoL was associated with either 68 minutes more sleep, 54 minutes less sedentary time, or 35 minutes more MVPA. Equivalent differences in outcomes were associated with several time reallocations. On a minute-for-minute basis, MVPA was 2 to 6 times as potent as sleep or sedentary time.

Insights into adolescent well-being from computerised analysis of written language.

To examine associations between patterns of language use and early adolescent well-being. Participants were 1763 Australian 11- to 12-year-olds in the Child Health CheckPoint. Six patterns of language use were identified from a writing activity using Linguistic Inquiry and Word Count and factor analysis: Acting in the present and future, Positive emotion, Gender and relationships, Self-aware, Inquisitive and time focused, and Confident. Well-being measures represented a spectrum from negatively to positively framed psychosocial health. Associations between language use and well-being were estimated using linear regression adjusted for age, sex and social disadvantage. Positive emotion (high emotional tone, positive emotion) was associated with better general well-being (standardised regression coefficient (SRC) 0.05; 95% confidence interval 0.00 to 0.11; p=0.04), life satisfaction (0.06; 0.01 to 0.11; p=0.03), psychosocial health (0.07; 0.02 to 0.12; p=0.01) and quality of life (QoL) (0.06; 0.01 to 0.11; p=0.02). Similarly, Self-aware (high first person singular pronouns, authentic, low clout) was associated with better general well-being, life satisfaction and psychosocial health (SRC 0.05, 0.09, 0.08), but Confident (high clout, first person plural pronouns, affiliation) was associated with worse life satisfaction, psychosocial health and QoL (SRC -0.06, -0.09, -0.06). If replicated in 'real-world' settings (e.g., social media), language patterns could provide naturalistic insights into early adolescents' well-being.

Plasma B Vitamers: Population Epidemiology and Parent-Child Concordance in Children and Adults.

Scope: B vitamers are co-enzymes involved in key physiological processes including energy production, one-carbon, and macronutrient metabolism. Studies profiling B vitamers simultaneously in parent–child dyads are scarce. Profiling B vitamers in parent–child dyads enables an insightful determination of gene–environment contributions to their circulating concentrations. We aimed to characterise: (a) parent–child dyad concordance, (b) generation (children versus adults), (c) age (within the adult subgroup (age range 28–71 years)) and (d) sex differences in plasma B vitamer concentrations in the CheckPoint study of Australian children. Methods and Results: 1166 children (11 ± 0.5 years, 51% female) and 1324 parents (44 ± 5.1 years, 87% female) took part in a biomedical assessment of a population-derived longitudinal cohort study: The Growing Up in Australia’s Child Health CheckPoint. B vitamer levels were quantified by UHPLC/MS-MS. B vitamer levels were weakly concordant between parent–child pairs (10–31% of variability explained). All B vitamer concentrations exhibited generation-specificity, except for flavin mononucleotide (FMN). The levels of thiamine, pantothenic acid, and 4-pyridoxic acid were higher in male children, and those of pantothenic acid were higher in male adults compared to their female counterparts. Conclusion: Family, age, and sex contribute to variations in the concentrations of plasma B vitamers in Australian children and adults.

Sleep and cardiometabolic risk: a cluster analysis of actigraphy-derived sleep profiles in adults and children.

Sleep plays an important role in cardiometabolic health. Although the importance of considering sleep as a multidimensional construct is widely appreciated, studies have largely focused on individual sleep characteristics. The association between actigraphy-derived sleep profiles and cardiometabolic health in healthy adults and children has not been examined. This study used actigraphy-measured sleep data collected between February 2015 and March 2016 in the Child Health CheckPoint study. Participants wore actigraphy monitors (GENEActiv Original, Cambs, UK) on their nondominant wrist for 7 days and sleep characteristics (period, efficiency, timing, and variability) were derived from raw actigraphy data. Actigraphy-derived sleep profiles of 1,043 Australian children aged 11-12 years and 1,337 adults were determined using K-means cluster analysis. The association between cluster membership and biomarkers of cardiometabolic health (blood pressure, body mass index, apolipoproteins, glycoprotein acetyls, composite metabolic syndrome severity score) were assessed using Generalized Estimating Equations, adjusting for geographic clustering, with sex, socioeconomic status, maturity stage (age for adults, pubertal status for children), and season of data collection as covariates. Four actigraphy-derived sleep profiles were identified in both children and adults: short sleepers, late to bed, long sleepers, and overall good sleepers. The overall good sleeper pattern (characterized by adequate sleep period time, high efficiency, early bedtime, and low day-to-day variability) was associated with better cardiometabolic health in the majority of comparisons (80%). Actigraphy-derived sleep profiles are associated with cardiometabolic health in adults and children. The overall good sleeper pattern is associated with more favorable cardiometabolic health.

Balancing time use for children's fitness and adiposity: Evidence to inform 24-hour guidelines for sleep, sedentary time and physical activity.

Daily time spent on one activity cannot change without compensatory changes in others, which themselves may impact on health outcomes. Optimal daily activity combinations may differ across outcomes. We estimated optimal daily activity durations for the highest fitness and lowest adiposity. Cross-sectional Child Health CheckPoint data (1182 11-12-year-olds; 51% boys) from the population-based Longitudinal Study of Australian Children were used. Daily activity composition (sleep, sedentary time, light physical activity [LPA], moderate-to-vigorous physical activity [MVPA]) was from 8-day, 24-hour accelerometry. We created composite outcomes for fitness (VO2max; standing long jump) and adiposity (waist-to-height ratio; body mass index; fat-to-fat-free log-ratio). Adjusted compositional models regressed activity log-ratios against each outcome. Best activity compositions (optimal time-use zones) were plotted in quaternary tetrahedrons; the overall optimal time-use composition was the center of the overlapping area. Time-use composition was associated with fitness and adiposity (all measures p<0.001). Optimal time use differed for fitness and adiposity. While both maximized MVPA and minimized sedentary time, optimal fitness days had higher LPA (3.4 h) and shorter sleep (8.25 h), but optimal adiposity days had lower LPA (1.0 h) and longer sleep (10.9 h). Balancing both outcomes, the overall optimal time-use composition was (mean [range]): 10.2 [9.5; 10.5] h sleep, 9.9 [8.8; 11.2] h sedentary time, 2.4 [1.8; 3.2] h LPA and 1.5 [1.5; 1.5] h MVPA. Optimal time use for children's fitness and adiposity involves trade-offs. To best balance both outcomes, estimated activity durations for sleep and LPA align with, but for MVPA exceed, 24-h guidelines.

Sleep and cardiometabolic health in children and adults: examining sleep as a component of the 24-h day

Study objectivesSleep, physical activity and sedentary time are all known to play a role in cardiometabolic health. Compositional data analysis (CoDA) enables us to examine associations between 24-h use of time and health outcomes. MethodsData were collected in the Child Health CheckPoint study, a one-off national population-cohort study conducted between February 2015 and March 2016. Wrist-worn actigraphy monitors (GENEActiv Original, Cambs, UK) were used to measure activity behaviours (sleep, physical activity and sedentary time) and sleep characteristics (sleep variability, midsleep, efficiency). CoDA was applied to determine the association between 24-h use of time and cardiometabolic risk markers (blood pressure; body mass index; apolipoprotein B/A1; glycoprotein acetyls; and composite metabolic syndrome score). Substitution modelling (one-for-remaining and one-for-one) examined the associations of reallocating sleep time with other activity behaviours. ResultsData were available for 1073 Australian children aged 11–12 years (50% male) and 1337 adults (13% male). Strong association was found between 24-h use of time and all cardiometabolic health outcomes. Longer sleep was associated with more favourable cardiovascular health. Sleep characteristics other than duration (efficiency, timing, variability) were weakly and inconsistently associated with outcomes. Reallocating time from sleep to moderate-vigorous physical activity (MVPA) had favourable associations with cardiometabolic health, but reallocating from sleep to sedentary time was associated with less favourable cardiometabolic health. ConclusionThe 24-h activity composition is strongly associated with cardiometabolic health in children and adults. Days with more sleep and MVPA are associated with improved cardiometabolic health.

No Obvious Impact of Caesarean Delivery on Childhood Allergic Outcomes: Findings From Australian Cohorts

Z Liao, KE Lamb, D Burgner. Arch Dis Child. 2020;105(7):664–670 To assess associations between cesarean delivery and the development of childhood asthma, eczema, and impaired lung function. The study included data from two contemporary population-based, longitudinal studies of allergic diseases in Australian children, HealthNuts ( n = 3135) and Longitudinal Study of Australian Children (LSAC, n = 3654), at age 6–7 years old and lung function data from LSAC’s Child Health CheckPoint ( n = 1502) at age 11–12 years old. Parent-reported data on delivery mode at baseline and child’s current asthma and eczema were extracted from HealthNuts and LSAC …

Takeaway food, sugar-sweetened beverages and preclinical cardiometabolic phenotypes in children and adults.

To investigate relationships between takeaway food and sugar-sweetened beverage (SSB) consumption with cardiometabolic phenotypes during childhood and mid-adulthood. Design: Cross-sectional Child Health CheckPoint within the national population-representative Longitudinal Study of Australian Children. Participants: 1838 children (mean age 11.5 years; 49.1% female) and 1846 adults (mean age 43.7 years; 87.6% female). Exposures: Self-reported takeaway food and SSB consumption ('frequent': ≥ weekly). Outcomes: Functional (pulse wave velocity (PWV), blood pressure (BP)) and structural (carotid intima-media thickness, retinal microvascular calibre) preclinical cardiovascular phenotypes; lipids (total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides). Analysis: Linear regression (exposure: takeaway or SSB consumption, individually or together) adjusted for age, sex and socio-economic position; and mediation analysis for body mass index (BMI). Associations were small among children (standardized mean difference (SMD) ≤0.15). In adults, associations were stronger with functional, but not structural, cardiovascular phenotypes and lipids, particularly for frequent takeaway food consumption (e.g. PWV (0.20 m/s; 95% confidence interval (CI) 0.03 to 0.37); systolic (3.3 mmHg; 95% CI 1.3 to 5.3) and diastolic BP (1.4 mmHg; 95% CI 0.2 to 2.6); LDL (0.10 mmol/L; 95% CI 0.02 to 0.18); HDL (-0.14 mmol/L; 95% CI -0.19 to -0.10) and triglycerides (0.30 mmol/L; 95% CI 0.12 to 0.48)]. BMI mediated associations between takeaway food consumption and PWV, BP, HDL and TG (proportion of mediation 34% to 75%), while mediation effects were smaller for SSB consumption. Frequent takeaway food consumption in adults was associated with adverse blood lipids and vascular function (mainly via BMI). Lack of strong associations in children highlights opportunities for prevention.