Physical activity is related to insulin sensitivity in children and adolescents, independent of adiposity: a review of the literature

Sleep duration and timing are prospectively linked with insulin resistance during late adolescence

OBJECTIVE

The aim of this study was to evaluate whether short sleep duration or later sleep timing is a risk factor for insulin resistance (IR) in late adolescence.

METHODS

Mexico City adolescents enrolled in a longitudinal birth cohort (ELEMENT) took part in two study visits during peri-puberty that occurred approximately 2 years apart. IR was assessed with serum glucose and insulin. Four groups were defined using puberty-specific cut points: no IR over the follow-up period, transition from normal to IR, transition from IR to normal, and IR at both time points. Baseline sleep assessments were measured with 7-day wrist actigraphy. Multinomial logistic regression models were used to evaluate associations between sleep duration and timing with homeostatic model assessment of insulin resistance categories, adjusting for age, sex, and baseline pubertal status.

RESULTS

Adolescents who were ≥ 1 hour below the sleep duration recommendations-for-age were 2.74 times more likely to develop IR (95% CI: 1.0-7.4). Similarly, adolescents who were in the latest category of sleep midpoint (>4:33 a.m.) were more likely than those with earliest midpoints (1 a.m.-3 a.m.) to develop IR (odds ratio = 2.63, 95% CI: 1.0-6.7). Changes in adiposity over follow-up did not mediate sleep and IR.

CONCLUSIONS

Insufficient sleep duration and late sleep timing were associated with development of IR over a 2-year period in late adolescence.

Exploring needs, barriers, and facilitators for promoting physical activity for children with intellectual developmental disorders: A qualitative focus group study

BACKGROUND

Many children with intellectual developmental disorders are insufficiently physically active and do not reach recommendations for physical activity. Pediatric healthcare providers play a key role in addressing these children's needs, including promoting interventions for physical activity.

AIM

To explore pediatric healthcare providers' perceived needs, barriers, and facilitators for promoting physical activity for children with intellectual developmental disorders.

METHODS

Semi-structured focus groups, analyzed using qualitative content analysis. Sixteen healthcare providers participated.

RESULTS

Main findings are the importance of parental support and engagement, need for structure, and stakeholder collaboration to bridge the gap between pediatric organizations and external stakeholders.

CONCLUSION

The study highlights the need for developing and implementing strategies to promote physical activity for children with intellectual developmental disorders in pediatric health care, and for producing guidelines regarding physical activity interventions for this vulnerable group.

Fat-free mass and maturity status are determinants of physical fitness performance in schoolchildren and adolescents

OBJECTIVES

The objective of the study was to verify whether (FFM), maturity status (MS) and chronological age (CA) are determinants of physical fitness performance, and to analyze FFM and physical performance aligned by CA and MS in children and adolescents.

METHODS

A descriptive correlational study was carried out in 863 schoolchildren. Weight, height, and waist circumference (WC) were evaluated. Body mass index (BMI), FFM, fat mass (FM), MS (Age at peak height velocity, APHV) were calculated. The physical tests of velocity 20 m, agility 5 m x 10rep, and horizontal jump (HJ) were evaluated.

RESULTS

The APHV was estimated in boys at 14.0 ± 0.36APHV and in girls at 11.96 ± 0.49APHV. The relationships between CA and APHV with FFM was r = 0.80 in boys and r = 0.44 to 0.45 in girls. The relationships between FFM and physical tests in boys were [HJ (r = 0.70), agility 5m x 10rep (r = -0.68), velocity (r = -0.61)] and in girls [HJ (r = 0.42), agility 5m x 10rep (r = -0.52), velocity (r = -0.20)]. The differences in FFM and physical fitness tests were more pronounced when aligned by APHV than by CA.

CONCLUSION

It was verified that both FFM, CA, and APHV are determinants of physical fitness performance. In addition, the APHV should be introduced in physical education as a means of ranking physical performance among schoolchildren.

Implementation of physical activity on prescription for children with obesity in paediatric health care (IMPA): protocol for a feasibility and evaluation study using quantitative and qualitative methods

BACKGROUND

Physical inactivity is a main cause of childhood obesity which tracks into adulthood obesity, making it important to address early in life. Physical activity on prescription (PAP) is an evidence-based intervention that has shown good effect on physical activity levels in adults, but has not been evaluated in children with obesity. This project aims to evaluate the prerequisites, determinants, and feasibility of implementing PAP adapted to children with obesity and to explore children's, parents', and healthcare providers' experiences of PAP.

METHODS

In the first phase of the project, healthcare providers and managers from 26 paediatric clinics in Region Västra Götaland, Sweden, will be invited to participate in a web-based survey and a subset of this sample for a focus group study. Findings from these two data collections will form the basis for adaptation of PAP to the target group and context. In a second phase, this adapted PAP intervention will be evaluated in a clinical study in a sample of approximately 60 children with obesity (ISO-BMI > 30) between 6 and 12 years of age and one of their parents/legal guardians. Implementation process and clinical outcomes will be assessed pre- and post-intervention and at 8 and 12 months' follow-up. Implementation outcomes are the four core constructs of the Normalization Process Theory; coherence, cognitive participation, collective action, and reflexive monitoring; and appropriateness, acceptability, and feasibility of the PAP intervention. Additional implementation process outcomes are recruitment and attrition rates, intervention fidelity, dose, and adherence. Clinical outcomes are physical activity pattern, BMI, metabolic risk factors, health-related quality of life, sleep, and self-efficacy and motivation for physical activity. Lastly, we will explore the perspectives of children and parents in semi-structured interviews. Design and analysis of the included studies are guided by the Normalization Process Theory.

DISCUSSION

This project will provide new knowledge regarding the feasibility of PAP for children with obesity and about whether and how an evidence-based intervention can be fitted and adapted to new contexts and populations. The results may inform a larger scale trial and future implementation and may enhance the role of PAP in the management of obesity in paediatric health care in Sweden.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04847271 , registered 14 April 2021.

Waist Circumference Is Not Associated with Impaired Fasting Blood Glucose in a Sample of Mexican Children and Teenagers: Results from a State Screening Program

A high waist circumference (WC) is used as a risk factor for impaired fasting blood glucose (IFG) in adults. This association is less studied in children and teenagers. The purpose of this study was to analyze the association between having a high WC and IFG by sex and age in a sample of Mexican children and teenagers. We analyzed the data of 12979 participants aged 5 to 17 years to calculate percentile references for uncorrected WC, corrected for height (WC/HT) and by height squared (WC/HT2) with quantile regression. A subsample of 2309 participants with fasting blood glucose samples (FBG), WC, WC/HT and WC/HT2 values was analyzed with logistic regression. A high WC, WC/HT, and WC/HT2 were considered at the sex- and age-specific 90th percentile from the subsample. The IFG was considered as FBG ≥100 mg/dL. Having a high WC, WC/HT, nor WC/HT2 was not significantly associated with IFG for either sex and age group (all p > 0.05). A high WC, either on its uncorrected or corrected for height values, was not an important assessment for predicting IFG in a sample of Mexican children and teenagers. This study provides percentile reference values specific for sex and age.

Physical activity impacts insulin sensitivity post metabolic bariatric surgery in adolescents with severe obesity

BACKGROUND/OBJECTIVES

We hypothesized that physical activity (PA) improves insulin sensitivity in adolescents with severe obesity beyond that attributable to metabolic bariatric surgery (MBS).

SUBJECTS/METHODS

StepWatch^TM monitors objectively measured PA in 88 participants in the Teen Longitudinal Assessment of Bariatric Surgery (Teen-LABS) study. Primary outcomes included absolute change in fasting insulin, HOMA-IR, and fasting glucose from pre-surgery (baseline) to 6, 12, 24, and 36 months post-MBS. SAS PROC TRAJ generated activity trajectories based on probability and individual participant step count trajectories. Linear regression models were used, adjusted for baseline value, visit, surgical procedure, sex, and percent change in BMI. Additional models adjusted for percent change in iliac waist circumference (IWC) or percent body fat (BF), measured by bio-impedance.

RESULTS

Two activity trajectories were identified: more active (MA, n = 13) and less active (LA, n = 75). MA baseline mean daily step count was >6000, increasing to >9000 at 2 years. LA mean daily step count remained at ~4000. Few participants recorded moderate step activity (cadence >80 steps/minute). Still, fasting insulin and HOMA-IR differed in association with activity trajectoy. MA was associated with a greater absolute decrease in fasting insulin (-7.8 μU/ml [95% CI: (-11.8, -3.7)], p ≤ 0.001) and a greater decrease in HOMA-IR (-1.9 [95% CI: (-3.0, -0.7)], p = 0.001), when adjusted for percent change in BMI. The significant independent effect of MA remained when adjusted for percent change in IWC or percent BF. Clinically, 100% of MA trajectory participants normalized fasting insulin, HOMA-IR, and fasting glucose by 6 months and normalization remained throughout the 36 months follow up. In contrast, 76.3 and 65.8% of LA trajectory participants normalized fasting insulin and HOMA-IR, respectively, by 12 months with 28.6% of both remaining normalized at 36 months.

CONCLUSIONS

PA is independently associated with improved insulin sensitivity beyond that attributable to MBS in adolescents with severe obesity.

Exercise and Insulin Resistance

In insulin resistance, alterations occur in the signalling pathways that modulate glucose uptake into cells, especially skeletal muscle cells, resulting in impaired glucose homeostasis. Glucose uptake into cells is controlled by a number of pathways, some of which are insulin-dependent. During exercise glucose uptake can occur independently of insulin regulation, and hence research into the effects of exercise on insulin resistance must be clearly defined to reflect whether glucose uptake has been enhanced as a result of the utilisation of these insulin-independent pathways, or whether exercise directly affects insulin resistance in cells. Research into the benefits of exercise for insulin resistance is also problematic in the need to clarify whether it is the exercise itself, or the visceral fat/weight loss that has resulted from the exercise, that has led to improved insulin sensitivity. The research presents a promising picture for the benefits of exercise in insulin resistance.

Insulin Sensitivity, Depression/Anxiety, and Physical Fitness in At-Risk Adolescents

Poor physical fitness contributes to the early progression of cardiometabolic disease, yet the physiological and psychological factors underpinning poor fitness in at-risk adolescents are not well understood. In this study, we sought to determine the relationship of physical fitness with two developmental phenomena of adolescence, insulin resistance and depression/anxiety symptoms among at-risk youth. We conducted secondary data analyses of 241 overweight or obese adolescents (12-17 years), drawn from two study cohorts. Insulin sensitivity index was derived from oral glucose tolerance tests. Adolescents self-reported depressive symptoms and anxiety symptoms on validated surveys. A walk/run test was administered to determine perceived exertion and physical fitness (distance traveled). Insulin sensitivity was positively associated with walk/run distance ( b =0.16, P< 0.01), even after accounting for all covariates. Anxiety symptoms were inversely related to perceived exertion ( b =-0.11, P< 0.05), adjusting for covariates. These findings suggest that insulin resistance and anxiety symptoms are associated with different dimensions of physical fitness in overweight or obese adolescents and could both potentially contribute to declining fitness and worsening metabolic outcomes in at-risk youth.

Design of a randomized controlled trial to decrease depression and improve insulin sensitivity in adolescents: Mood and INsulin sensitivity to prevent Diabetes (MIND)

BACKGROUND

Depressive symptoms often manifest in adolescence and predict worsening insulin sensitivity, a key precursor in the path to β-cell failure and type 2 diabetes (T2D).

OBJECTIVE

To assess the efficacy of a six-week cognitive-behavioral group versus six-week health education group for improving insulin sensitivity and preserving β-cell function in adolescent girls at-risk for T2D with depressive symptoms and evaluate mechanisms underlying the association between depression and insulin dynamics.

DESIGN

Randomized controlled trial of N = 150 12-17-year-old girls with overweight/obesity (body mass index [BMI; kg/m2] ≥85th percentile), elevated depressive symptoms (Center for Epidemiologic Studies-Depression Scale [CES-D] total score > 20), and diabetes family history.

METHODS

Girls at-risk for T2D with elevated depressive symptoms are recruited from the Denver-metropolitan area and randomized to participate in one of two six-week interventions. The cognitive-behavioral group is a depression prevention program involving psycho-education, restructuring negative thoughts, and behavioral activation. The health education group is a didactic control that provides knowledge about healthy living. Participants are assessed at baseline, immediate post-intervention, and one-year follow-up. Primary outcomes are insulin sensitivity and β-cell function from oral glucose tolerance tests. Secondary outcomes are disinhibited eating, physical activity, sleep, and cortisol.

SUMMARY

Results from this adequately powered randomized controlled trial will determine whether decreasing depressive symptoms with a behavioral health program preventatively alters insulin sensitivity and β-cell function trajectories in adolescents at-risk for T2D. Results from the MIND Project will add to knowledge of the contribution of depressive symptoms to T2D risk.

[Metabolic syndrome in children aged 6 to 12 years with obesity in public schools of seven municipalities in the State of Mexico]

OBJECTIVE

To estimate the prevalence of Metabolic Syndrome (MS), its components and its association with obesity and cardiovascular risk in school age children.

MATERIALS AND METHODS

A cross-sectional study of 1,017 children from 6 to 12 years of age. Anthropometric information, blood pressure, glucose, insulin, cholesterol, HDLc, LDLc and triglycerides were collected. The presence of MS and its components were determined by criteria of Cook et. al. (2003), modified for children and adolescents. In the analysis, the children were grouped by aged group of 6 to 9 and 10 to 12 years. The association between MS, obesity and cardiovascular risk was estimated using Student's t-test and Mann-Whitney U test, Chi-square test and logistic regression.

RESULTS

The MS was present with 54.6% in obese children. Obesity was the characteristic of greater association to suffer from MS with an OR=8.62 p<0.001.

CONCLUSIONS

MS is high among children with obesity, and is mostly associated with insulin resistance and atherogenic risk.

An MG53-IRS1-interaction disruptor ameliorates insulin resistance

Mitsugumin 53 (MG53) is an E3 ligase that induces insulin receptor substrate-1 (IRS-1) ubiquitination and degradation in skeletal muscle. We previously demonstrated that the pharmaceutical disruption of the MG53-IRS-1 interaction improves insulin sensitivity by abrogating IRS-1 ubiquitination and increasing IRS-1 levels in C2C12 myotubes. Here, we developed a novel MG53-IRS-1 interaction disruptor (MID-00935) that ameliorates insulin resistance in diet-induced obese (DIO) mice. MID-00935 disrupted the molecular interaction of MG53 and IRS-1, abrogated MG53-induced IRS-1 ubiquitination and degradation and improved insulin signaling in C2C12 myotubes. Oral administration of MID-00935 increased insulin-induced IRS-1, Akt, and Erk phosphorylation via increasing IRS-1 levels in the skeletal muscle of DIO mice. In DIO mice, MID-00935 treatment lowered fasting blood glucose levels and improved glucose disposal in glucose and insulin tolerance tests. These results suggest that MID-00935 may be a potential muscle-targeting drug candidate for treating insulin resistance.

Effect on the Metabolic Biomarkers in Schoolchildren After a Comprehensive Intervention Using Electronic Media and In-Person Sessions to Change Lifestyles: Community Trial

BACKGROUND

Obesity is a chronic low-intensity state of inflammation with metabolic alterations that, when acquired during childhood, lead to severe illness in adults. Encouraging healthy eating habits and physical activity is the basis for preventing and treating obesity and its complications.

OBJECTIVE

To evaluate how a comprehensive intervention promoting healthy eating habits and physical activities in schools affects children's metabolic biomarkers.

METHODS

Of four Mexico City primary schools in this study, two groups of children that were recruited at their schools were assigned to a 12-month intervention group (IG) and the other two were assigned to control groups (CGs). The intervention had two components: (1) parents/schoolchildren attended in-person educational sessions promoting healthy eating and physical activity habits, and were provided printed information; and (2) parents were able to seek information through a website, and also received brief weekly mobile phone text messages. Anthropometric measurements and fasting blood samples were taken from both groups of children at baseline and again after 12 months.

RESULTS

The study involved 187 children in the IG and 128 in the CG. Regardless of each child's nutritional status at the beginning of the study, the intervention improved metabolic parameters; the IG showed a negative effect on glucose concentrations (-1.83; CI 95% -3.06 to -0.60), low-density lipoprotein-cholesterol (-2.59; CI 95% -5.12 to -0.06), insulin (-0.84; CI 95% -1.31 to -0.37), and homeostasis model to assess the insulin resistance index (HOMA-IR; -0.21; CI 95% -0.32 to -0.09) in comparison to the CG. HOMA-IR improved in children who had higher than baseline body mass index z-scores.

CONCLUSIONS

Intervention through multiple components that promoted healthier eating and physical activity habits improved the metabolic parameters of the children in the study after one year, regardless of their nutritional status.

Prevention of insulin resistance in adolescents at risk for type 2 diabetes with depressive symptoms: 1-year follow-up of a randomized trial

BACKGROUND

Depression is associated with poor insulin sensitivity. We evaluated the long-term effects of a cognitive behavioral therapy (CBT) program for prevention of depression on insulin sensitivity in adolescents at risk for type 2 diabetes (T2D) with depressive symptoms.

METHODS

One-hundred nineteen adolescent females with overweight/obesity, T2D family history, and mild-to-moderate depressive symptoms were randomized to a 6-week CBT group (n = 61) or 6-week health education (HE) control group (n = 58). At baseline, posttreatment, and 1 year, depressive symptoms were assessed, and whole body insulin sensitivity (WBISI) was estimated from oral glucose tolerance tests. Dual energy X-ray absorptiometry assessed fat mass at baseline and 1 year. Primary outcomes were 1-year changes in depression and insulin sensitivity, adjusting for adiposity and other relevant covariates. Secondary outcomes were fasting and 2-hr insulin and glucose. We also evaluated the moderating effect of baseline depressive symptom severity.

RESULTS

Depressive symptoms decreased in both groups (P < .001). Insulin sensitivity was stable in CBT and HE (ΔWBISI: .1 vs. .3) and did not differ between groups (P = .63). However, among girls with greater (moderate) baseline depressive symptoms (N = 78), those in CBT developed lower 2-hr insulin than those in HE (Δ-16 vs. 16 μIU/mL, P < .05). Additional metabolic benefits of CBT were seen for this subgroup in post hoc analyses of posttreatment to 1-year change.

CONCLUSIONS

Adolescent females at risk for T2D decreased depressive symptoms and stabilized insulin sensitivity 1 year following brief CBT or HE. Further studies are required to determine if adolescents with moderate depression show metabolic benefits after CBT.

Update on the effects of physical activity on insulin sensitivity in humans

PURPOSE AND METHODS

This review presents established knowledge on the effects of physical activity (PA) on whole-body insulin sensitivity (SI) and summarises the findings of recent (2013-2016) studies.

DISCUSSION AND CONCLUSIONS

Recent studies provide further evidence to support the notion that regular PA reduces the risk of insulin resistance, metabolic syndrome and type 2 diabetes, and SI improves when individuals comply with exercise and/or PA guidelines. Many studies indicate a dose response, with higher energy expenditures and higher exercise intensities, including high intensity interval training (HIIT), producing greater benefits on whole-body SI, although these findings are not unanimous. Aerobic exercise interventions can improve SI without an associated increase in cardiorespiratory fitness as measured by maximal or peak oxygen consumption. Both aerobic and resistance exercise can induce improvements in glycaemic regulation, with some suggestions that exercise regimens including both may be more efficacious than either exercise mode alone. Some studies report exercise-induced benefits to SI that are independent of habitual diet and weight loss, while others indicate an association with fat reduction, hence the debate over the relative importance of PA and weight loss continues. During exercise, muscle contraction stimulated improvements in SI are associated with increases in AMPK activity, which deactivates TCB1D1, promoting GLUT4 translocation to the cell membrane and thereby increasing glucose uptake. Postexercise, increases in Akt deactivate TCB1D4 and thereby increase GLUT4 translocation to the cell membrane. The reduction in intramuscular saturated fatty acids and concomitant reductions in ceramides, but not diacylglycerols, provide a potential link between intramuscular lipid content and SI. Increased skeletal muscle capillarisation provides another independent adaptation through which SI is improved, as does enhanced β cell activity. Recent studies are combining exercise interventions with dietary and feeding manipulations to investigate the potential for augmenting the exercise-induced improvements in SI and glycaemic control.

Physical Activity Throughout Adolescence and Hba1c in Early Adulthood: Birth Cohort Study

BACKGROUND

Physical inactivity is responsible for 7% of diabetes deaths worldwide, but little is known whether low levels of physical activity (PA) during adolescence increase the risk of diabetes in early adulthood. We evaluated the cross-sectional and longitudinal associations between PA throughout adolescence and HbA1c concentration in early adulthood.

METHODS

HbA1c was measured by high performance liquid chromatography. PA was assessed by self-report at the ages of 11, 15, and 18 years and by accelerometry at the ages of 13 (subsample) and 18 years. The loss percentages of follow up were 12.5% at 11 years, 14.4% at 15 years, and 18.7% at 18 years.

RESULTS

At 18 years, boys showed higher HbA1c than girls. At age 18 years, accelerometrybased PA at 18 years was inversely related to HbA1c levels in boys. Self-reported leisure-time PA at ages 11, 15, and 18 were unrelated to HbA1c in both genders. PA at 13 years of age was unrelated to HbA1c among both genders. In trajectory analysis, PA and accelerometer PA trajectories were not associated with later HbA1c.

CONCLUSIONS

Objectively measured PA at 18 years was cross-sectionally inversely associated with HbA1c in boys only. No prospective associations were identified.

Physical activity attenuates the mid-adolescent peak in insulin resistance but by late adolescence the effect is lost: a longitudinal study with annual measures from 9-16 years (EarlyBird 66)

AIMS/HYPOTHESIS

The aim of this work was to test whether the mid-adolescent peak in insulin resistance (IR) and trends in other metabolic markers are influenced by long-term exposure to physical activity.

METHODS

Physical activity (7 day ActiGraph accelerometry), HOMA-IR and other metabolic markers (glucose, fasting insulin, HbA1c, lipids and BP) were measured annually from age 9 years to 16 years in 300 children (151 boys) from the EarlyBird study in Plymouth, UK. The activity level of each child was characterised, with 95% reliability, by averaging their eight annual physical activity measures. Age-related trends in IR and metabolic health were analysed by multi-level modelling, with physical activity as the exposure measure (categorical and continuous) and body fat percentage (assessed by dual-energy X-ray absorptiometry) and pubertal status (according to age at peak height velocity and Tanner stage) as covariates.

RESULTS

The peak in IR at age 12-13 years was 17% lower (p < 0.001) in the more active adolescents independently of body fat percentage and pubertal status. However, this difference diminished progressively over the next 3 years and had disappeared completely by the age of 16 years (e.g. difference was -14% at 14 years, -8% at 15 years and +1% at 16 years; 'physical activity × age(2), interaction, p < 0.01). Triacylglycerol levels in girls (-9.7%, p = 0.05) and diastolic blood pressure in boys (-1.20 mmHg, p = 0.03) tended to be lower throughout adolescence in the more active group.

CONCLUSIONS/INTERPRETATION

Our finding that physical activity attenuates IR during mid-adolescence may be clinically important. It remains to be established whether the temporary attenuation in IR during this period has implications for the development of diabetes in adolescence and for future metabolic health generally.

Exercise capacity and muscle strength and risk of vascular disease and arrhythmia in 1.1 million young Swedish men: cohort study

OBJECTIVE

To investigate the associations of exercise capacity and muscle strength in late adolescence with risk of vascular disease and arrhythmia.

DESIGN

Cohort study.

SETTING

General population in Sweden.

PARTICIPANTS

1.1 million men who participated in mandatory military conscription between 1 August 1972 and 31 December 1995, at a median age of 18.2 years. Participants were followed until 31 December 2010.

MAIN OUTCOMES

Associations between exercise capacity and muscle strength with risk of vascular disease and subgroups (ischaemic heart disease, heart failure, stroke, and cardiovascular death) and risk of arrhythmia and subgroups (atrial fibrillation or flutter, bradyarrhythmia, supraventricular tachycardia, and ventricular arrhythmia or sudden cardiac death). Maximum exercise capacity was estimated by the ergometer bicycle test, and muscle strength was measured as handgrip strength by a hand dynamometer. High exercise capacity or muscle strength was deemed as above the median level.

RESULTS

During a median follow-up of 26.3 years, 26 088 vascular disease events and 17 312 arrhythmia events were recorded. Exercise capacity was inversely associated with risk of vascular disease and its subgroups. Muscle strength was also inversely associated with vascular disease risk, driven by associations of higher muscle strength with lower risk of heart failure and cardiovascular death. Exercise capacity had a U shaped association with risk of arrhythmia, driven by a direct association with risk of atrial fibrillation and a U shaped association with bradyarrhythmia. Higher muscle strength was associated with lower risk of arrhythmia (specifically, lower risk of bradyarrhythmia and ventricular arrhythmia). The combination of high exercise capacity and high muscle strength was associated with a hazard ratio of 0.67 (95% confidence interval 0.65 to 0.70) for vascular events and 0.92 (0.88 to 0.97) for arrhythmia compared with the combination of low exercise capacity and low muscle strength.

CONCLUSIONS

Exercise capacity and muscle strength in late adolescence are independently and jointly associated with long term risk of vascular disease and arrhythmia. The health benefit of lower risk of vascular events with higher exercise capacity was not outweighed by higher risk of arrhythmia.

Paediatrics, insulin resistance and the kidney

Systemic insulin resistance is becoming more prevalent in the young due to modern lifestyles predisposing to the metabolic syndrome and obesity. There is also evidence that there are critical insulin-resistant phases for the developing child, including puberty, and that renal disease per se causes systemic insulin resistance. This review considers the factors that render children insulin resistant, as well as the accumulating evidence that the kidney is an insulin-responsive organ and could be affected by insulin resistance.

Physical activity and cardiovascular risk factors in childhood cancer survivors

BACKGROUND

Childhood cancer survivors (CCS) are at high risk of developing treatment-related late effects, including cardiovascular disease and diabetes. Late effects can be exacerbated by low physical activity (PA) levels. Relationships between PA and cardiovascular risk factors during childhood have not been well described in CCS.

PROCEDURE

PA and cardiovascular risk factors were measured cross-sectionally in 319 CCS and 208 sibling controls aged 9-18 years. Comparisons between CCS and controls and associations of outcomes with PA (dichotomized at 60 min/day or treated as continuous) were performed with linear regression.

RESULTS

Among CCS, the high PA group had lower percent fat mass (24.4% vs. 29.8%, P < 0.0001), abdominal subcutaneous fat (67.9 vs. 97.3 cm³ , P = 0.0004), and abdominal visceral fat (20.0 vs. 24.9 cm³ , P = 0.007) and greater lean body mass (41.3 vs. 39.5 kg, P = 0.009) than the low PA group. Comparing CCS to controls, differences in waist circumference (P_interaction  = 0.04), percent fat mass (P_interaction  = 0.04), and abdominal subcutaneous (P_interaction  = 0.02) and visceral (P_interaction  = 0.004) fat between low and high PA groups were greater in CCS than controls, possibly due to greater overall adiposity in CCS.

CONCLUSIONS

High PA in CCS resulted in an improved cardiovascular profile, consisting primarily of lower fat mass and greater lean mass, similar to that observed in controls. This suggests interventions directed to increase PA in CCS may reduce the risk of future cardiovascular disease. Pediatr Blood Cancer 2015;62:305-310. © 2014 Wiley Periodicals, Inc.

Lifestyle interventions to reduce diabetes and cardiovascular disease risk among children

Diseases once associated with older adulthood, type 2 diabetes and cardiovascular disease, are increasingly diagnosed in children and adolescents. Interventions designed to assist adults in modifying dietary and physical activity habits have been shown to help prevent the development of type 2 diabetes and cardiovascular disease in adults. Given the unfortunate rise in both of these diseases in pediatric populations, it is increasingly important to begin prevention efforts in childhood or prenatally. There is strong empirical support for utilizing lifestyle interventions to prevent these diseases in adults; it is not clear whether the same holds true for pediatric populations. The present review examines lifestyle management efforts to prevent type 2 diabetes and cardiovascular disease in children across socioecological levels. Recommendations are made for expanding the traditional focus of lifestyle interventions from dietary and physical activity behaviors to target additional risks for these diseases such as smoking and depression in youth.

Health behaviour in children and adolescents with type 1 diabetes compared to a representative reference population

Objective

We provide a population-based overview of health behaviours of children and adolescents with type 1 diabetes in comparison to the general population, and analyse their relevance for glycaemic control and self-rated health status.

Methods

Data from questionnaires of 11- to 17-year-old children and adolescents with diabetes (n = 629) were compared to a representative sample (n = 6,813).

Results

Children and adolescents with type 1 diabetes had a significantly increased odds of infrequent physical activity (adjusted OR 1.56), short overall duration of physical activity per week (OR 1.55, difference -1.3 hours/week), and high daily computer use (OR 2.51). They had a lower odds of active and passive smoking (OR 0.31 and OR 0.29), and high daily television time (OR 0.68). The odds of an at least good and excellent self-rated health status was increased with intense physical activity, and decreased with active smoking and prolonged daily use of computer and television. Active smoking and prolonged daily use of computer were associated with higher HbA1c.

Conclusions

Children and adolescents with type 1 diabetes showed a different profile of health behaviour. Their overall health may improve if their education stresses specifically frequent physical activity with longer overall duration and less frequent television or computer use.

Behavioral contributions to the pathogenesis of type 2 diabetes

Behavioral contributions to the pathogenesis of prediabetes and Type 2 diabetes (T2D) include lifestyle behaviors including dietary intake, exercise, sedentariness, sleep, and stress. The purpose of this paper is to review evidence for the metabolic pathways by which the behavior is linked to T2D. Evidence for interventions, which change each of the lifestyle behaviors, is discussed. The article will close with a brief discussion on how new technologies may provide opportunities to better understand relationships between moment-to-moment fluctuations in behaviors and diabetes pathogenesis, as well as provide opportunities to personalize and adapt interventions to achieve successful behavior change and maintenance of that change. Especially promising are new technologies, which assist in tracking lifestyle behaviors along with clinical and metabolic outcomes.

Vegetarian diet-induced increase in linoleic acid in serum phospholipids is associated with improved insulin sensitivity in subjects with type 2 diabetes

BACKGROUND AND AIMS:

Fatty acids are important cellular constituents that may affect many metabolic processes relevant for the development of diabetes and its complications. We showed previously that vegetarian diet leads to greater increase in metabolic clearance rate of glucose (MCR) than conventional hypocaloric diet. The aim of this secondary analysis was to explore the role of changes in fatty acid composition of serum phospholipids in diet- and exercise-induced changes in MCR in subjects with type 2 diabetes (T2D).

METHODS:

Subjects with T2D (n=74) were randomly assigned into a vegetarian group (VG, n=37) following vegetarian diet or a control group (CG, n=37) following a conventional diet. Both diets were calorie restricted (−500 kcal day^–1). Participants were examined at baseline, 12 weeks of diet intervention and 24 weeks (subsequent 12 weeks of diet were combined with aerobic exercise). The fatty acid composition of serum phospholipids was measured by gas liquid chromatography. MCR was measured by hyperinsulinemic isoglycemic clamp. Visceral fat (VF) was measured by magnetic resonance imaging.

RESULTS:

Linoleic acid (LA; 18:2n6) increased in VG (P=0.04), whereas it decreased in CG (P=0.04) in response to dietary interventions. It did not change significantly after the addition of exercise in either group (group × time P<0.001). In VG, changes in 18:2n6 correlated positively with changes in MCR (r=+0.22; P=0.04) and negatively with changes in VF (r=−0.43; P=0.01). After adjustment for changes in body mass index, the association between 18:2n6 and MCR was no longer significant. The addition of exercise resulted in greater changes of phospholipid fatty acids composition in VG than in CG.

CONCLUSION:

We demonstrated that the insulin-sensitizing effect of a vegetarian diet might be related to the increased proportion of LA in serum phospholipids.