Less physical activity and more varied and disrupted sleep is associated with a less favorable metabolic profile in adolescents

The relationship between multiple sleep dimensions and obesity in adolescents: A systematic review

Sleep is an involuntary behaviour, biologically fundamental to survival and wellbeing. However, sleep is increasingly neglected, with significant health implications. Recent research has identified associations between sleep duration, quality, timing and risk of overweight/obesity in children and adults. The aim of this review was to systematically identify and examine research that investigates the relationships between multiple objective and subjective sleep outcomes and objective adiposity measures in adolescents. A systematic review of literature, published to December 2022, was conducted using ten bibliographic databases. Search terms included objective and subjective sleep/circadian rhythm outcomes, objective adiposity measurements, and adolescents aged 8-18 years. Eighty-nine studies were included in the final review. Sleep outcomes were synthesized into three sleep domains: pre-sleep, during sleep and post-sleep outcomes. In summary, pre-sleep outcomes (including poor sleep hygiene, later chronotype and increased variability and later sleep timings) and increased sleep disturbance are consistently significantly associated with increased obesity and adiposity in adolescents. The relationship between during-sleep outcomes (sleep quality and efficiency) with adiposity and obesity measures was mixed. These findings suggest that adapting an individual's schedule to best suit chronotype preference and improving sleep hygiene, including a consistent bedtime routine, could reduce adiposity and obesity in adolescents.

Sleep Variability, Eating Timing Variability, and Carotid Intima-Media Thickness in Early Adulthood

Background Day-to-day variability in sleep patterns and eating timing may disrupt circadian rhythms and has been linked with various adverse cardiometabolic outcomes. However, the extent to which variability in sleep patterns and eating timing relate to atherosclerotic development in subclinical stages remains unclear. Methods and Results Generally healthy adults (N=62, 29.3±7.3 years, 66% female) completed 14 days of sleep and dietary assessments via wrist accelerometry and photo-assisted diet records, respectively. Variability in sleep duration, sleep onset, eating onset (time of first caloric consumption), eating offset (time of last caloric consumption), and caloric midpoint (time at which 50% of total daily calories are consumed) were operationalized as the SD across 14 days for each variable. Separate regression models evaluated the cross-sectional associations between sleep and eating variability metrics with end-diastolic carotid intima-media thickness (CIMT) measured via ultrasonography. Models adjusted for age, sex, systolic blood pressure, sleep duration, and total energy intake. Each 60-minute increase in sleep duration SD and sleep onset SD were associated with a 0.049±0.016 mm (P=0.003) and 0.048±0.017 mm (P=0.007) greater CIMT, respectively. Variability in eating onset and offset were not associated with CIMT; however, each 60-minute increase in caloric midpoint SD was associated with a 0.033±0.015 mm greater CIMT (P=0.029). Exploratory post hoc analyses suggested that sleep duration SD and sleep onset SD were stronger correlates of CIMT than caloric midpoint SD. Conclusions Variability in sleep patterns and eating timing are positively associated with clinically relevant increases in CIMT, a biomarker of subclinical atherosclerosis, in early adulthood.

Sleep variability and regularity as contributors to obesity and cardiometabolic health in adolescence

OBJECTIVE

Adolescence is a developmental stage of critical changes in sleep and its circadian timing when the contribution of abnormal sleep variability (amount) and sleep regularity (timing) to obesity and its associated adverse cardiometabolic health outcomes appears to increase. The aim of this study was to summarize findings from studies conducted in adolescents examining both sleep variability and regularity in relation to obesity and cardiometabolic health. Gaps in research and potential causal pathways that future studies should examine are highlighted.

RESULTS

Nightly deviations in sleep duration and sleep midpoint appear to contribute to the development of obesity and associated adverse cardiometabolic outcomes in youth. Studies show that increased sleep variability and irregularity are associated with obesity, decreased physical activity, dysregulated eating and inadequate diet, metabolic dysfunction, impaired cardiac autonomic balance, and elevated blood pressure in adolescents.

CONCLUSIONS

A stable circadian timing of sleep is essential to the overall physical well-being of youth. Emerging evidence supports that sleep variability and circadian misalignment, including sleep irregularity, contribute to adverse obesity-related health outcomes early on in adolescence. Future studies should focus on the underlying behavioral and biological mechanisms in the causal pathway between day-to-day deviations in the amount and timing of sleep and obesity.

The relationship between anemia and obesity

INTRODUCTION

Obesity is linked to a variety of unfavourable outcomes, including anaemia, which is a serious global public health problem. The prevalence of obesity along with anaemia suggests a relationship between obesity and anaemia. Recent studies have demonstrated strong associations between anaemia and obesity, chronic diseases, ageing, hepato-renal impairment, chronic infection, autoimmune diseases, and widespread malignancy. Thus, the intersection point of obesity and anaemia is an important area of attention.

AREA COVERED

This paper reviews the pathophysiology of obesity and anaemia. Then, It deliberates the relationship between obesity and different types of anaemia and other clinical forms associated with anaemia.

EXPERT OPINION

Obesity, especially obesity-related to excessive visceral fat distribution, is accompanied by several disturbances at the endothelial, hormonal, and inflammatory levels. These disturbances induce activation of several mechanisms that contribute to the anaemic state. Over-weight patients with chronic anaemias are required to maintain the related vitamins and minerals at optimum levels and appropriate BMI. In addition, a regular clinical follow-up is essential to be scheduled to reduce the risk of complications associated with anaemia in obese patients.

Childhood obesity prevention: what can be achieved?

PURPOSE OF REVIEW

Childhood obesity is a pandemic generating an enormous individual and socioeconomic burden worldwide. This narrative review summarizes recent evidence on successful and recommended prevention strategies according to age groups and different levels of interventions.

RECENT FINDINGS

Effective prevention of childhood obesity is feasible and most successful early in life up to preschool age, and it should include a multicomponent approach, integrating individuals, family and society. Trials that improve nutrition and/or enhance physical activity are the cornerstones of childhood obesity prevention on an individual level. However, their efficacy is determined by the combination of interventions for the target age group. Further, improving family support and sleep, as well as reducing screen time, lead to favourable results. Many research gaps remain, including a lack of effective interventions for high-risk groups.

SUMMARY

As a multifactorial condition, childhood obesity requires a multicomponent approach. Interventions should be developmental stage-specific and adjusted to the setting. Current research gaps need to be targeted by future trials, with a special focus on the benefit of the most vulnerable groups. From a systems response perspective, a paradigm shift from interventions focusing on the individual to approaches that target society as a whole is warranted.

Sleep timing and health indicators in children and adolescents: a systematic review

INTRODUCTION

To continue to inform sleep health guidelines and the development of evidence-based healthy sleep interventions for children and adolescents, it is important to better understand the associations between sleep timing (bedtime, wake-up time, midpoint of sleep) and various health indicators. The objective of this systematic review was to examine the associations between sleep timing and 9 health indicators in apparently healthy children and adolescents 5 to 18 years old.

METHODS

Studies published in the 10 years preceding January 2021 were identified from searches in four electronic databases. This systematic review followed the guidelines prescribed in PRISMA 2020, the methodological quality and risk of bias were scored, and the summary of results used a best-evidence approach for accurate and reliable reporting.

RESULTS

Forty-six observational studies from 21 countries with 208 992 unique participants were included. Sleep timing was assessed objectively using actigraphy in 24 studies and subjectively in 22 studies. The lack of studies in some of the health outcomes and heterogeneity in others necessitated using a narrative synthesis rather than a metaanalysis. Findings suggest that later sleep timing is associated with poorer emotional regulation, lower cognitive function/academic achievement, shorter sleep duration/ poorer sleep quality, poorer eating behaviours, lower physical activity levels and more sedentary behaviours, but few studies demonstrated associations between sleep timing and adiposity, quality of life/well-being, accidents/injuries, and biomarkers of cardiometabolic risk. The quality of evidence was rated as "very low" across health outcomes using GRADE.

CONCLUSION

The available evidence, which relies on cross-sectional findings, suggests that earlier sleep timing is beneficial for the health of school-aged children and adolescents. Longitudinal studies and randomized controlled trials are needed to better advance this field of research. (PROSPERO registration no.: CRD42020173585).

Rest-activity circadian rhythm and impaired glucose tolerance in adults: an analysis of NHANES 2011-2014

INTRODUCTION

Circadian rhythm disturbance occurs in type 2 diabetes, yet it is unknown whether it also exists in the prediagnostic phase of the disease. Thus, we examined the association of rest-activity circadian rhythm with 2-hour glucose levels and the risk of impaired glucose tolerance (IGT) in a nationally representative sample of adults without diabetes using a cross-sectional design.

RESEARCH DESIGN AND METHODS

We analyzed data from 2760 adults without diabetes (age ≥20) with at least 4 days of validated accelerometer recordings and a valid oral glucose tolerance test from the National Health and Nutrition Examination Survey 2011-2014. Non-parametric rest-activity circadian rhythm parameters were derived from the accelerometer recordings.

RESULTS

In the models adjusting for multiple covariates, a one-quantile increase in relative amplitude (ie, increased circadian rhythmicity) was associated with 2.66 mg/dL decrease in 2-hour glucose level (95% CI -3.94 to -1.38, p<0.001) and a decreased odds of IGT (OR 0.75, 95% CI 0.63 to 0.89, p=0.002). A one-quantile increase in intradaily variability (ie, increased rhythm fragmentation) was associated with 3.01 mg/dL increase in 2-hour glucose level (95% CI 1.52 to 4.49, p=0.001) and an increased odds of IGT (OR 1.37, 95% CI 1.19 to 1.58, p<0.001).

CONCLUSIONS

Circadian disruption is significantly associated with impaired glucose homeostasis in a general population of adults without diabetes. The association of circadian rhythm abnormalities with indicators of the pre-diabetic state suggests that circadian dysfunction may contribute to early disease pathogenesis.

Fat-free/lean body mass in children with insulin resistance or metabolic syndrome: a systematic review and meta-analysis

BACKGROUND

Lean / Fat Free Body Mass (LBM) is metabolically involved in active processes such as resting energy expenditure, glucose uptake, and myokine secretion. Nonetheless, its association with insulin sensitivity / resistance / glucose tolerance and metabolic syndrome remains unclear in childhood.

METHODS

The current investigation aimed to examine the differences in fat-free mass /lean body mass according to the presence of insulin sensitivity/insulin resistance/glucose tolerance/metabolic syndrome in children. A systematic search was carried out in Medline/PubMed, Embase, Scopus, Web of Science, and SciELO, covering the period from each database's respective start to 21 June 2021. Two researchers evaluated 7111 studies according to the inclusion criteria: original human studies, written in English or Spanish, evaluating fat-free mass/lean body mass in children and adolescents including both with and without insulin sensitivity/insulin resistance /glucose tolerance and metabolic syndrome and reported the differences between them in terms of fat free mass/lean body mass. The results of the studies were combined with insulin sensitivity, insulin, resistance, glucose tolerance and metabolic syndrome. The standardized mean difference (SMD) in each study was calculated and combined using the random-effects model. Heterogeneity between studies was tested using the index of heterogeneity (I2), leave-one-out sensitivity analyses were performed, and publication bias was assessed using the Egger and Begg tests.

RESULTS

Finally, 15 studies which compared groups defined according to different glucose homeostasis criteria or metabolic syndrome out of 103 eligible studies were included in this systematic review and 12 studies in the meta-analysis. Meta-analysis showed lower fat-free mass/lean body mass percentage in participants with insulin resistance/glucose tolerance/metabolic syndrome (SMD -0.47; 95% CI, - 0.62 to - 0.32) while in mass units (kg), higher values were found in the same group (SMD, 1.01; 95% CI, 0.43 to 1.60).

CONCLUSIONS

Our results identified lower values of fat-free mass/lean body mass (%) in children and adolescents with insulin resistance/glucose tolerance/metabolic syndrome and higher values of fat-free mass/lean body mass when these are expressed in kg. The evidence of the impact of lean mass on children's glucose homeostasis or metabolic syndrome is limited, so future studies research should focus on explaining the effect of fat-free mass/lean body mass on different metabolic outcomes. Moreover, it may be interesting to evaluate the quality (muscle density) or functional (muscle strength) outcomes in addition to both absolute (kg) and relative (%) values in future studies. The systematic review was prospectively registered at PROSPERO (registration number CRD42019124734; available at: http://www.crd.york.ac.uk/prospero [accessed: 05 April 2019]).

Poor Sleep Quality Decreases Concurrent Training Benefits in Markers of Metabolic Syndrome and Quality of Life of Morbidly Obese Patients

Background: Sleep quality (SQ) plays a role in multiple activities of daily living, but little is known about its role in concurrent training [CT, high-intensity interval (HIIT) plus resistance training (RT)] adaptations for metabolic syndrome (MetS) and health-related quality of life (HRQoL) markers. The aim of the present study was to determine the effects of a 20-week CT programme on MetS and HRQoL markers according to the SQ of morbidly obese patients. Methods: Twenty-nine morbidly obese patients were allocated to one of two groups: good sleep quality (GSQ, n = 15, 38.07 ± 12.26 years) and poor sleep quality (PSQ, n = 14, 40.79 ± 11.62 years). HRQoL, body mass index, waist circumference (WC), systolic and diastolic blood pressure (SBP and DBP, respectively), and plasma outcomes were measured. Results: The GSQ group reported significant changes (pre- vs. post-intervention) in WC (114.0 ± 3.1 vs. 110.4 ± 3.4 cm, p = 0.012), SBP (137.0 ± 4.3 vs. 125.6 ± 1.8 mmHg, p = 0.006), and HRQoL general health (51.33 ± 21.08 vs. 64.33 ± 16.24, p = 0.020). By contrast, the PSQ group showed significant changes only in SQ (9.00 ± 2.42 vs. 5.36 ± 2.84, p = 0.004). Conclusions: Morbidly obese PSQ patients showed a lower response for improving MetS and HRQoL markers after a 20-week CT programme than GSQ peers. However, there was a greater effect size for decreasing WC and SBP in favour of the GSQ compared with the PSQ group, suggesting that there are limitations to CT benefits on these outcomes in the PSQ group. These results call for more complex future studies.