Evidence of the influence of physical activity on the metabolic syndrome and/or on insulin resistance in pediatric populations: a systematic review

A scoping review of physical activity interventions in youth attending child and adolescent mental health services

BACKGROUND

There has been an international effort to improve physical health in general and in those with mental illness. Physical activity (PA) may be beneficial as an adjunctive treatment for mental health disorders and to improve physical well-being.

AIMS

The objective of this scoping review is to understand the extent and type of evidence in relation to PA interventions offered in child and adolescent mental health services (CAMHS). Eligibility was determined using the Population, Concept, Context framework. Studies were included if the participants were under 18 years old, attending CAMHS and where PA interventions were offered.

METHODS

PubMed, MEDLINE, Embase, Cochrane Library, CINAHL, PsycINFO and SportDiscus were searched without language or date restrictions. Titles and abstracts, followed by full texts, were screened by two independent reviewers. Two reviewers carried out data extraction, and discrepancies in any of these processes were resolved in consultation with a third reviewer.

RESULTS

After 2213 non-duplicate titles and abstracts were screened, 2090 were excluded and 123 full texts were screened. Seventeen studies met inclusion criteria. Included studies demonstrated PA interventions to be effective in reducing depressive symptoms and improving psychosocial functioning. While no study reported significant changes in anthropometric measurements, 2 studies demonstrated increased aerobic fitness.

CONCLUSION

Evidence that PA interventions are being offered in CAMHS worldwide is limited. Included studies demonstrate potential benefits in depressive symptoms, psychosocial functioning, self-esteem and aerobic fitness in youth attending CAMHS. Future research should identify effective ways to incorporate exercise interventions in CAMHS and evaluate long-term benefits.

Family structure and the association with physical activity-Findings from 40 countries participating in the Health Behaviour in School-aged Children (HBSC) study

BACKGROUND

The family has been acknowledged as central to developing physical activity (PA) beliefs and behaviours. However, increased diversity in family structures has developed over the last decades. This study examines the association between family structure and PA among adolescents and cross-national variations in the associations.

METHODS

The data are from the 2013/14 Health Behaviours in School-Aged Children study, involving nationally representative samples of 11-, 13- and 15-year-olds (n = 211,798) from 40 countries. Multilevel Poisson regression analysis was used to examine the associations between family structure and moderate to vigorous physical activity (MVPA) and vigorous physical activity (VPA) by age, gender, socioeconomic status (SES), and geographic region.

RESULTS

Living with one versus two parents was associated with a reduced likelihood of daily 60 min MVPA for boys (IRR = 0.96, 95% CI: 0.92, 0.99) and ≥ 4 times/week VPA (IRR 0.93, 95% CI: 0.91, 0.95). This impact on MVPA differed across individual-level SES (high SES; IRR = 0.92, (p <0.05), low SES; IRR = 1.04, (ns)), and was for VPA only significant for those with siblings (IRR = 0.93, 95% CI: 0.91, 0.96). Cross-country variations in the association between living with one versus two parents were observed, most pronounced for VPA. These differences varied by region, primarily explained by country-level SES differences between regions. The likelihood of daily 60 min MVPA also increased with siblings in the main house (IRR 1.11, 95% CI: 1.07, 1.14), and ≥ 4 times/week VPA decreased with grandparents in the main house (IRR 0.91, 95% CI: 0.89,0.94).

CONCLUSIONS

Family structure correlated with PA, but cross-country differences exist. The findings are relevant for the development of policies and programs to facilitate PA, especially in countries where living with one versus two parents was unfavourable. Additional country-specific research is needed to identify challenges for engaging in PA related to family structure.

Bioactive compounds in childhood obesity and associated metabolic complications: Current evidence, controversies and perspectives

Obesity represents the most frequent chronic disease among children worldwide, with a significant global burden on society. Metabolically unhealthy obesity (MUO) can affect children since their first years of life, and novel therapeutic strategies to tackle metabolic complications are under investigation. This review focuses on bioactive compounds and their possible beneficial effects on obesity, particularly omega-3, docosahexaenoic acid, vitamin D, biotics, polysaccharide macromolecules, polyphenols, inositols, alpha lipoic acid, and bromelaine. Our aim is to summarize current evidence about bioactive compounds in the treatment of obesity, highlighting recent findings on their use in children and adolescents. Most studied molecules are omega-3 and vitamin D, despite the heterogeneity between the studies. Moreover, given the emerging interest in the gut-brain axis in the link between metabolic health and microbiota, various studies on prebiotics, probiotics, synbiotics, postbiotics and polysaccharide macromolecules have been considered. Some preclinical studies seem to highlight a possible role of the polyphenols, even if their clinical evidence is still discussed. Lastly, we describe possible effects of inositols and alpha-lipoic acid. Despite some dietary supplements seem to be promising in overweight subjects, only in a few of them a dose/response efficacy has been found in the pediatric age. Innovative, well-designed and targeted clinical trials are then needed to prove the beneficial effects of these compounds that could support the standard behavioral therapy for obesity.

Physical activity to ameliorate the negative mental health effects of COVID-19-induced confinement

Mental health is strongly affected by physical (PA) and sedentary (SA) activity. In the current study, the relationships of PA and sedentary activity (SA) with mental status amid confinement caused by COVID-19 were examined. The study is self-reporting, survey-based, and cross-sectional in design. The study was conducted in Jordan and included 1744 participants (≥18 years old). The participants' mental status was obtained using the Depression-Anxiety-Stress Scale (DASS). The results showed involvement in both PA and SA during COVID-19-induced confinement. The involvement includes walking (77.2%), running (70.3%), cycling (84.9%), swimming (83.1%), sports (82.9%), weightlifting (86.4%), watching TV (79.4%), using electronics (86.3%), and logging to social media (85.1%). Lower DASS scores were associated (p < 0.05) with lower walking, running, and weightlifting but not (p > 0.05) with cycling and swimming PA. Additionally, DASS scores (p < 0.05) were associated with changes in television viewing but not (p > 0.05) with electronics and social media use during confinement. In conclusion, individuals who experienced higher levels of stress, anxiety, and depression were more likely to turn to more PA and less SA. These findings are important and suggest that individuals during confinement find PA a useful strategy to mitigate the negative mental effects of the pandemic.

Trimester two gestational exposure to bisphenol A and adherence to mediterranean diet are associated with adolescent offspring oxidative stress and metabolic syndrome risk in a sex-specific manner

Background

Exposure to prenatal bisphenol A (BPA) and Mediterranean Diet Score (MDS) has been linked to metabolic risk in child offspring. It remains unclear if independent and interactive effects persist in adolescence.

Methods

We examined prenatal BPA and MDS on adolescent offspring metabolic syndrome risk score (MRS) and 8-isoprostane (8-iso), a biomarker of oxidative stress. Data from maternal-adolescent dyads from a Mexico City cohort were utilized, including trimester-specific prenatal BPA from spot urine and MDS from food frequency questionnaires. Offspring socio-demographic data and biomarkers to estimate MRS and 8-iso were obtained during peri-adolescence.

Results

Adjusted linear regression models examined associations between trimester-specific BPA, MDS, and BPA^*MDS on outcomes. Sex-stratified analyses revealed a significant association between MDS with increased 8-iso (β = 0.064, p < 0.05), and a marginal association between trimester two BPA with increased 8-iso (β = 0.237), while MDS modified the marginal association between BPA and 8-iso in females (β = 0.046). A negative, marginal association was observed between trimester two BPA and MRS (β = - 0.728), while BPA ^* MDS was marginally, positively associated with MRS (β = 0.152) in males.

Conclusions

Study findings indicate that trimester two prenatal BPA and maternal adherence to a Mediterranean diet may have sexually dimorphic effects on adolescent offspring oxidative stress and metabolic syndrome risk.

Indicators to Assess Physical Health of Children and Adolescents in Activity Research-A Scoping Review

Sufficient physical activity can help promote and maintain health, while its lack can jeopardize it. Since health and physical activity lay their foundation for later life in childhood and adolescence, it is important to examine this relationship from the beginning. Therefore, this scoping review aims to provide an overview of physical health indicators in children and adolescents in research on the effects of physical activity and sedentary behavior. We identified the indicators used to quantify or assess physical health and summarized the methods used to measure these indicators. We systematically searched Scopus, Pubmed, and Web of Science databases for systematic reviews. The search yielded 4595 records from which 32 records were included in the review. The measurements for physical health reported in the reviews contained measures of body composition, cardiometabolic biomarkers, physical fitness, harm/injury, or bone health. Body composition was the most used indicator to assess and evaluate physical health in children, whereas information on harm and injury was barely available. In future research longitudinal studies are mandatory to focus on the prospective relationships between physical activity or sedentary behavior, and physical health.

Sedentary behavior moderates the relationship between physical activity and cardiometabolic risk in young Latino children

This study investigated the role of objectively measured moderate-vigorous physical activity (MVPA) and sedentary behavior on cardiometabolic risk factors of young Latino children. We hypothesized that MVPA would be associated with lower cardiometabolic risk when sedentary behavior is low. We studied 86 primarily low-income, Latino children using a cross-sectional study design. The study sample consisted of 51 girls and 35 boys, with mean age 5.6 (SD = .53) years. Physical activity was measured by accelerometry, anthropometric measures obtained, and fasting blood samples were used to measure cardiometabolic risk factors. Greater levels of sedentary behavior were associated with increased waist circumference (rs = .24, p < .05) and metabolic risks. MVPA, however, had significant beneficial associations with all cardiometabolic risk factors (rs-range = -.20 to -.45, p < .05) with the exception of plasma insulin. MVPA predicted latent variables representing anthropometric risk (β = -.57, p < .01), cardiac risk (β = -.74, p < .01), and metabolic risk (β = -.88, p < .01). Sedentary behavior significantly moderated the effect of MVPA on anthropometric (β-interaction = .49, p < .01), cardiac (β-interaction = .45, p < .01), and metabolic risk (β-interaction = .77, p < .01), such that more MVPA was associated with better health outcomes under conditions of lower sedentary behavior. The model explained 13%, 22%, and 45% variance in anthropometric, cardiac, and metabolic risk factors, respectively. Increased MVPA is associated with decreased cardiometabolic risk in young Latino children, particularly when sedentary behavior is low.

Prevalence of Metabolic Syndrome in Children and Adolescents with Type 1 Diabetes Mellitus and Possibilities of Prevention and Treatment: A Systematic Review

Overweight and obesity are an increasingly common problem, not only among the healthy population, but also in adolescents with type 1 diabetes (T1DM). Excess body weight is related to many cardiometabolic complications as well as a high risk of metabolic syndrome (MetS). The purpose of this systematic review is to provide a concise and critical overview of the prevalence of MetS in children and adolescents with T1DM and, ultimately, to discuss prevention and treatment options. The study was conducted in accordance with PRISMA guidelines. This review shows that, apart from the growing percentage of overweight and obese children and adolescents with T1DM (on average 20.1% and 9.5%, respectively), the problem of the increasing incidence of MetS (range from 3.2 to 29.9%, depending on the criteria used) is one of the most important phenomena of our time. One of the methods of prevention and treatment is a combined approach: changing eating habits and lifestyle, but there are also reports about the beneficial effects of the gut microflora.

Macronutrient intake and physical activity levels in individuals with and without metabolic syndrome: An observational study in an urban population

BACKGROUND

We aimed to compare dietary macronutrient intake and physical activity level (PAL) between community-based samples of Iranian adults with metabolic syndrome (MetS+) and without metabolic syndrome (MetS-).

METHODS

This cross-sectional study was conducted among 3800 men and women aged 35-65 years. The International Diabetes Federation (IDF) criteria were used to define MetS. A 24-hour recall was used to evaluate dietary intake. The James and Schofield human energy requirements equations were used to calculate PAL and questions were categorized into time spent on activities during work (including housework), during non-work time, and in bed.

RESULTS

The mean ± standard deviation (SD)age of the MetS+ and MetS- subjects was, respectively, 48.8 ± 7.8 years (521 men and 1178 women) and 47.6 ± 7.5 years (714 men and 1222 women) (P = 0.930). The mean energy intake was higher in the MetS+ men compared with MetS- men (1977.4 ± 26.6 vs. 1812.7 ± 21.7 Kcal; P < 0.001). Crude and energy-adjusted intake from total fat was lower in MetS+ women compared with MetS- women (both P < 0.010). PALs were lower in MetS+ compared with MetS- participants (P < 0.001). After adjusting for confounders, no significant association was observed between the intake of individual macronutrients and MetS. In contrast, PAL was inversely associated with the incidence of MetS [OR = 0.34 (95% CI: 0.17-0.57); P < 0.001].

CONCLUSION

In the current study, there was an inverse relationship between PAL and the risk of MetS, but no association between individual dietary macronutrients intake and the incidence of MetS.

Assessing and Managing the Metabolic Syndrome in Children and Adolescents

The metabolic syndrome (MetS) is a group of cardiovascular risk factors that are associated with insulin resistance and are driven by underlying factors, including visceral obesity, systemic inflammation, and cellular dysfunction. These risks increasingly begin in childhood and adolescence and are associated with a high likelihood of future chronic disease in adulthood. Efforts should be made at both recognition of this metabolic risk, screening for potential associated Type 2 diabetes, and targeting affected individuals for appropriate treatment with an emphasis on lifestyle modification. Effective interventions have been linked to reductions in MetS-and in adults, reductions in the severity of MetS have been linked to reduced diabetes and cardiovascular disease.

Which predictors differentiate between obese children and adolescents with cardiometabolic complications and those with metabolically healthy obesity?

BACKGROUND/AIMS

Childhood obesity and associated metabolic comorbidities is a major global health concern. Metabolically healthy obesity (MHO) may represent a subgroup of individuals in which excessive body fat accumulation does not lead to adverse metabolic effects. We aimed to determine the prevalence of MHO among obese Israeli children and adolescents and to find predictors for metabolically unhealthy obesity (MUO).

METHODS

In a retrospective study, demographic, anthropometric, lifestyle, and cardiometabolic data were retrieved from medical records of patients with a body mass index (BMI) >95th percentile aged 6 to 17.6 years, attending a tertiary pediatric obesity clinic between 2008 and 2015, with at least 1 year of follow-up. Participants were dichotomized as either MHO or MUO based on cardiometabolic risk factor clustering (blood pressure, serum lipids, and glucose). Multivariable logistic regression was used to determine predictors of MUO.

RESULTS

Of the 230 children (median age 9.9 years) fulfilling study criteria, 48 (20.9%) were classified as MHO. Occurrence of MUO was associated with male gender, Arabic ethnicity, higher BMI-SD score, higher tri-ponderal mass index (TMI), and higher insulin resistance (IR) (presence of acanthosis nigricans and a higher level of homeostasis model assessment-IR [HOMA-IR]). Male gender (odds ratio [OR] 2.27, P = .033), presence of acanthosis nigricans at baseline (OR 2.35, P = .035), and a greater increase in BMI-SDS during follow-up (OR 2.82, P = .05) were the best predictors of MUO.

CONCLUSIONS

The MHO phenotype was present in only 20.9% of obese Israeli children. MUO was significantly associated with male gender, with presence of acanthosis nigricans, and with a greater increase in BMI-SDS during follow-up.

Resistance Training Effects on Metabolic Function Among Youth: A Systematic Review

PURPOSE

This systematic review evaluates the relationship between resistance training and metabolic function in youth.

METHODS

PubMed, Embase, Cochrane Library, Web of Science, CINAHL, and ClinicalTrials. gov were searched for articles that (1): studied children (2); included resistance training (3); were randomized interventions; and (4) reported markers of metabolic function. The selected studies were analyzed using the Cochrane Risk-of-Bias Tool.

RESULTS

Thirteen articles met inclusion criteria. Mean age ranged from 12.2 to 16.9 years, but most were limited to high school (n = 11) and overweight/obese (n = 12). Sample sizes (n = 22-304), session duration (40-60min), and intervention length (8-52 wks) varied. Exercise frequency was typically 2-3 d/wk. Resistance training was metabolically beneficial compared with control or resistance plus aerobic training in 5 studies overall and 3 out of the 4 studies with the fewest threats to bias (p ≤ .05); each was accompanied by beneficial changes in body composition, but only one study adjusted for change in body composition.

CONCLUSIONS

Limited evidence suggests that resistance training may positively affect metabolic parameters in youth. Well-controlled resistance training interventions of varying doses are needed to definitively determine whether resistance training can mitigate metabolic dysfunction in youth and whether training benefits on metabolic parameters are independent of body composition changes.

Maternal gestational weight gain and objectively measured physical activity among offspring

Objective

Animal studies have suggested that maternal weight-related factors during pregnancy can program offspring physical activity in a sex-dependent manner. However, there is limited evidence in humans. The purpose of this study was to investigate the association between maternal gestational weight gain (GWG) and offspring total physical activity (TPA) level and to determine whether these associations are moderated by sex of offspring or maternal pre-pregnancy weight status.

Method

We studied 56 boys (mean age = 3.7 years, standard deviation (SD) 0.5) and 57 girls (mean age = 3.5±0.5 years) enrolled in licensed childcare centers. TPA was objectively measured using Actical^® accelerometers. Information on pre-pregnancy body mass index (BMI), GWG, and other maternal factors were collected with a maternal health questionnaire. Associations between GWG, as a continuous variable or categorically (inadequate, adequate, and excessive), and offspring TPA were analysed using linear mixed models to take into account the intraclass correlation between the clusters (childcare centers). Models were adjusted for gestational age, accelerometer weartime, socioeconomic status, and pre-pregnancy BMI status.

Results

We found a significant sex interaction (P-value = 0.009). In boys, greater GWG was associated with decreased offspring TPA (β = -3.2 counts⋅1000⁻¹/d, 95% confidence intervals (CI) = -6.4–0.02, P-value = 0.049). In girls born to mothers categorized as overweight or obese, the association between the GWG and TPA followed an inverted U-shape curve (β for GWG squared = -0.1 counts⋅1000⁻¹/d, 95% CI = (-0.2 –-0.04), P-value = 0.005). In contrast, a U-shaped curve was found in girls born to mothers classified as lean (pre-pregnancy BMI<25 kg/m²) (β for GWG squared = 0.7 counts⋅1000⁻¹/d, 95% CI = 0.2–1.2, P-value = 0.011). In boys, TPA in offspring was higher among women with inadequate GWG compared to adequate GWG (P-value = 0.0137), whereas no significant differences were found in girls (P-value = 0.107).

Conclusion

Maternal GWG can be an important biological marker of offspring TPA. These findings support the sex-dependent early developmental programming influence of GWG on TPA.

An update on the assessment and management of metabolic syndrome, a growing medical emergency in paediatric populations

In the last decades the increasing rate of obesity in children and adolescents worldwide has led to the onset in paediatric age of metabolic syndrome, a disease commonly associated to adulthood. Central obesity, dyslipidaemia, hyperglycaemia, and hypertension are typical features of metabolic syndrome that seem to hesitate often in type 2 diabetes, cardiovascular disease, non-alcoholic fatty liver disease, and many other clinical conditions. Thus preventing and curing metabolic syndrome in paediatric patients is becoming an urgent need for public health. While diagnostic criteria and therapy of metabolic syndrome in adults are very well defined, there is no consensus on the definition of metabolic syndrome in children and adolescents as well as on healing approaches. The aim of this review is to describe the recent advances on the pathogenesis and clinical outcomes of paediatric metabolic syndrome. We then detail the therapeutic strategies (i.e. dietary regimens, physical exercise, nutraceuticals, and medications) employed to manage the disease. Finally, we analyse the safety profile of the drugs used in children and adolescents by performing a retrospective review of paediatric adverse reactions reported in the FDA's Adverse Event Reporting System database.

Physical Activity, Sedentary Behavior, Cardiorespiratory Fitness and Metabolic Syndrome in Adolescents: Systematic Review and Meta-Analysis of Observational Evidence

Background

Metabolic syndrome (MetS) has been diagnosed in adolescents and among the associated factors are low levels of physical activity, sedentary behavior over long periods and low cardiorespiratory fitness. However, specifically in adolescents, studies present conflicting results. The aim of the present study was to conduct a systematic review and meta-analysis of observational studies, in order to map the association between physical activity, sedentary behavior, cardiorespiratory fitness and MetS in adolescents.

Methods

A search was performed in the databases PubMed, SPORTDiscus, LILACS and the Cochrane Library. For the meta-analysis, the odds ratio (OR) was calculated together with the respective confidence intervals (95% CI), in which the measures of effect were analyzed by dichotomous data (exposure variables) with MetS used as events.

Results

Eighteen studies were included in the meta-analysis. Primary analysis demonstrated that low levels of physical activity (OR = 1.35 [1.03 to 1.79]; p = 0.03) and low cardiorespiratory fitness (OR = 4.05 [2.09 to 7.87]; p < 0.01) were significantly associated with the development of MetS, while for sedentary behavior, represented by screen time > 2 hours/day, a significant association was not identified (OR = 1.20 [0.91 to 1.59]; p = 0.20). Subgroup analyses demonstrated that the association between low physical activity and MetS was dependent on the use of the accelerometry technique (OR = 2.93 [1.56 to 5.47]; p < 0.01). Screen time > 2 hours/day was significantly associated with MetS only on weekends (OR = 2.05 [1.13 to 3.73]; p = 0.02). With respect to cardiorespiratory fitness, a significant association with MetS was found independent of the maximal oxygen uptake (VO₂max) measurement method.

Conclusions

Low levels of physical activity, low indices of cardiorespiratory fitness and sedentary behavior, represented by screen time > 2 hours/day on weekends, were significantly associated with the development of MetS in adolescence.

Metabolic Syndrome in Children and Adolescents

BACKGROUND

Juvenile obesity is associated with multiple cardiometabolic comorbidities, which may culminate in the metabolic syndrome (MetS).

METHODS

Based on a narrative review, the current knowledge of prevalence and the underlying metabolic principles regarding juvenile obesity and MetS are summarized to compile up-to-date information. In addition, the role of lifestyle as well as positive and negative influencing factors are focused on.

RESULTS

The prevalence of MetS occurs between 1 and up to 23% in the total pediatric population and in up to 60% amongst the obese and overweight. It can be considered as the consequence of multiple processes in terms of lifestyle, perinatal programming, and (epi-)genetic pathways; however, the complex underlying mechanisms and their interplay are not completely understood.

CONCLUSION

Besides preventive approaches, the growing number of obese children and youth as well as its consequences call for effective and lasting therapeutic measures.

Active and strong: physical activity, muscular strength, and metabolic risk in children

OBJECTIVES

This study explored the associations among physical activity, muscular strength, and metabolic risk among children.

METHODS

The sample included 378 Portuguese children (213 girls; 9-11 years). Moderate-to-vigorous physical activity was assessed by accelerometry and children were classified as active (≥60 min/day) or insufficiently active (<60 min/day). Static strength was expressed as the ratio of handgrip strength/body weight and used to classify children as having high (≥P50) or low (<P50) muscular strength. Children were classified into four groups: active and high strength, active and low strength, insufficiently active and high strength, insufficiently active and low strength. A continuous metabolic risk score was computed from cardiometabolic risk factors.

RESULTS

In general, the insufficiently active and low strength group had the worst metabolic risk score, and the active and high strength group had the best. Significant differences were found within physical activity groups for metabolic risk: children classified as "active and high strength" and "insufficiently active and high strength" had better metabolic risk scores than "active and low strength" and "insufficiently active and low strength", respectively.

CONCLUSIONS

Muscular strength has a relevant role in attenuating the association between physical inactivity and metabolic risk in children; a further benefit was identified in children with high physical activity and high muscular strength.

Exploring the Adolescent Fall in Physical Activity: A 10-yr Cohort Study (EarlyBird 41)

INTRODUCTION

Contemporary adolescents are deemed inactive, especially girls, but whether for biological reasons associated with their maturation, changes in their behavior or because of environmental constraints, is uncertain. We examined the trends in physical activity (PA) in relation to both biological and environmental factors in an attempt to establish what drives activity patterns from childhood through adolescence.

METHODS

Physical activity (7-d Actigraph accelerometry) was measured annually from 5 to 15 yr in a single cohort of some 300 UK children. Total PA (TPA; in-school and out-of-school separately and combined as whole day) and intensity-specific PA (sedentary, light, and moderate-and-vigorous [MVPA]) were analyzed. Biological age (years before/after measured peak height velocity) and pubertal stage (self-reported pubic hair development-Tanner staging) were also measured as was socioeconomic status (postcode-derived index of multiple deprivation [IMD]).

RESULTS

Total PA was stable from 5 to 8 yr (trend P = 0.10) but fell progressively from 9 to 15 yr (by approximately 30% in girls and approximately 20% in boys, both P < 0.001; sex interaction, P < 0.01). Half of this fall was attributable to light intensity PA and only a quarter to MVPA. The decline in PA was related similarly to chronological and biological age, whereas pubertal stage explained the more rapid PA decline in girls (puberty-adjusted sex interaction, P = 0.51). Total PA fell to the same extent for in-school and out-of-school settings (both P < 0.001), and for lower and higher IMD areas (both P < 0.001). Total PA tracked moderately to strongly from childhood into adolescence (r = 0.58; P < 0.001).

CONCLUSIONS

The adolescent decline in PA is consistent across different environmental settings, attributable to falls in light-intensity/habitual activity and influenced by puberty, suggesting that the inactivity of adolescence may, in part, be under biological control.

Are physical activity, sedentary behaviors and sleep duration associated with body mass index-for-age and health-related quality of life among high school boys and girls?

BACKGROUND

Previous studies reported lower health-related quality of life (HRQOL) scores in overweight and obese adolescents compared to their normal weight counterparts; however, few studies investigated the association between obesity-related behaviors including physical activity and sedentary behaviors and HRQOL in adolescents. This study aimed at investigating the relationship between physical activity, sedentary behaviors, sleep duration and body mass index-for-age (BMI-for-age) and HRQOL among high school Tehranian students.

METHODS

A total of 465 high school students (48.8 % girls) were recruited from three different socio-economic zones in Tehran. The BMI-for-age was determined and physical activity and HRQOL were assessed using validated questionnaires including Quantification de l'Activite Physique en Altitude Chez les Enfants (QAPACE) and Pediatric Quality of Life Inventory (PedsQL) respectively.

RESULTS

Over one third of students (38.5 %) were either overweight or obese. The means of all self- and parent-reported HRQOL scores were significantly lower in girls, compared to boys, except for the parent-reported social functioning subscale. Mean hours of daily sleeping were significantly higher in girls, compared to boys (8.16 ± 1.27 vs. 7.73 ± 1.22 respectively; p < 0.05). Both girls and boys spent more time on sedentary activities than engaging in sport activities. During school and vacation periods, boys had significantly higher daily energy expenditure (DEE) compared to girls (p < 0.05). Only DEE during school period had a significant inverse correlation with BMI-for-age in boys but not girls (r = -0.14, p < 0.05). In addition, self-reported HRQOL scores were significantly associated with weekly hours adolescents spent on videogames/internet, listening to music and reading, watching TV, sports as well as DEE through sex-specific patterns. However according to parents' perspective only weekly hours spent on listening to music and readings and sport activities were significantly associated with their children HRQOL scores.

CONCLUSION

In summary, time spent on physical and sedentary activities were not associated with BMI-for-age, although both of these were associated with the HRQOL of high school students. The potential role of sedentary activities and physical activity should be considered in future interventions aimed at improving HRQOL in adolescents.

Upregulation of miR-497 induces hepatic insulin resistance in E3 rats with HFD-MetS by targeting insulin receptor

OBJECTIVE

The study aims to find regulatory microRNA(s) responsible for down-regulated insulin receptor (InsR) in the liver of HFD-MetS E3 rats with insulin resistance.

METHODS

Firstly, hepatic insulin resistance in HFD-MetS E3 rats was evaluated by RT-qPCR, western blotting, immunohistochemistry and PAS staining. Secondly, the candidate miRNAs targeting rat InsR were predicted through online softwares and detected in the liver of HFD-MetS E3 rats with insulin resistance. Then, the expression of InsR, phosphorylated IRS-1 (pIRS-1) at Tyr632, phosphorylated AKTs (pAKTs) at Ser473 and Thr308, phosphorylated GSK-3β (p GSK-3β) at Ser9, phosphorylated GS (pGS) at Ser641 and the glycogen content were detected in CBRH-7919 cells treated with 100 nM insulin for different time periods by western blotting or PAS staining respectively, after transient transfection with miR-497 mimics or inhibitors for 24 h. Lastly, the relation between miR-497 and InsR was further determined using dual luciferase reporter assay.

RESULTS

Elevated miR-497 was negatively related with down-regulated InsR in the liver of HFD-MetS E3 rats with insulin resistance. Comparing with the mNC group, glycogen content and the expression of InsR, pIRS-1 (Tyr632), pAKTs (Ser473 and Thr308) and pGSK-3β (Ser9) decreased significantly in CBRH-7919 cells, while pGS (Ser641) increased significantly, after transient transfection with miR-497 mimics for 24 h and treatment with 100 nM insulin for corresponding time periods, counter to those results in CBRH-7919 cells after similar procedures with miR-497 inhibitors and insulin. In addition, dual luciferase reporter assay further confirmed that miR-497 can bind to the 3'UTR of rat InsR.

CONCLUSION

Insulin receptor is the target gene of miR-497, and elevated miR-497 might induce hepatic insulin resistance in HFD-MetS E3 Rats through inhibiting the expression of insulin receptor and confining the activation of IRS-1/PI3K/Akt/GSK-3β/GS pathway to insulin.

Early detection of comorbidity in psoriasis: recommendations of the National Conference on Healthcare in Psoriasis

BACKGROUND

Psoriasis is associated with an increased rate of comorbidities, whose early detection has been adopted into the national healthcare goals. To date, agreed recommendations on early detection in the context of routine dermatological care are missing. The objective of this study was the interdisciplinary development of screening algorithms.

METHODS

The development of the consensus paper was based on a three-step process. First, the National Conference on Healthcare in Psoriasis, convening on behalf of the German Society of Dermatology (DDG) and the Professional Association of German Dermatologists (BVDD), developed a definition of the requirements, areas of application, conception, and methodology of a screening tool. Secondly, based on a literature search, individual working groups compiled evidence for the use of screening parameters. In a third step, an interdisciplinary working group adopted the algorithms in a Delphi consensus process.

RESULTS

The associated working groups evaluated more than 2,000 publications on 15 different comorbidities. A screening algorithm was agreed on for the following twelve indications: arterial hypertension, dyslipidemia, obesity, diabetes mellitus, metabolic syndrome, nonalcoholic steatohepatitis, depression, nicotine abuse, alcohol abuse, chronic inflammatory bowel disease, psoriasis arthritis, and malignant lymphoma. In this context, the requirements of everyday dermatological care were addressed in particular.

CONCLUSIONS

With respect to screening for comorbidities in psoriasis, standardized and consented algorithms are available, which - on national level - may be implemented as a screening tool within the framework of PsoNet - German Psoriasis Networks.

Leisure-time physical activity and cardiometabolic risk among children and adolescents

OBJECTIVE

To assess the effect of Leisure-time physical activity (LTPA) on cardiometabolic risk by nutritional status in Mexican children and adolescents.

METHODS

This was a cross-sectional study conducted with 1,309 participants aged between 5 and 17 years. Nutritional status was classified according to the BMI Z-score by age and gender. A previously validated questionnaire was used to evaluate LTPA; a cardiometabolic risk score was calculated. Multiple linear regression analysis was performed to assess the effect of LTPA on cardiometabolic risk.

RESULTS

After adjusting for risk factors, mild LTPA were positively associated with cardiometabolic risk score (βMildvsIntenseLTPA: 0.68; 95% CI: 0.18 to 1.18; pfortrend = 0.007). This association became stronger when estimated for overweight (β MildvsIntenseLTPA: 1.24; 95% CI: 0.24 to 2.24; pfortrend = 0.015) and obese participants (β MildvsIntenseLTPA: 1.02; 95% CI: 0.07 to 1.97; pfortrend= 0.045).

CONCLUSION

Mild LTPA was positively associated with cardiometabolic risk in overweight and obese children and adolescents. Given the emerging childhood obesity epidemic in Mexico, these results may be useful in the design of strategies and programs to increase physical activity levels in order to achieve better health.

Association between leisure time physical activity and metabolic syndrome: a meta-analysis of prospective cohort studies

A great number of prospective studies have investigated the relationship between leisure time physical activity (LTPA) and metabolic syndrome (MetS) risk. However, the results have been inconsistent. The aim of this study was to clarify the relationship between LTPA and MetS risk. Literature databases were searched including PubMed and Embase up to June 2013. A total of 17 studies, including 64,353 participants and 11,271 incident cases, were included in the meta-analysis. A high level of LTPA was statistically associated with decreased risk of MetS [high vs. low: relative risk (RR) = 0.80, 95 % confidence interval (CI) 0.75-0.85], whereas a moderate level of LTPA was weakly associated with decreased risk of MetS (moderate vs. low: RR = 0.95, 95 % CI 0.91-1.00). Subgroup analyses indicated that the association between a moderate level of LTPA and decreased risk of MetS was only significant in men (moderate vs. low: RR = 0.88, 95 % CI 0.81-0.97) and in studies with more than a 10-year follow-up period (moderate vs. low: RR = 0.90, 95 % CI 0.84-0.97). A high level of LTPA was statistically associated with decreased risk of MetS in each subgroup. A higher level of LTPA is associated with a lower risk of MetS. These findings could have public health implications with regard to prevention of MetS through lifestyle interventions.

Predictors of metabolically healthy obesity in children

OBJECTIVE

To determine the prevalence of metabolically healthy obesity (MHO) in children and examine the demographic, adiposity, and lifestyle predictors of MHO status.

RESEARCH DESIGN AND METHODS

This cross-sectional study included 8-17 year olds with a BMI ≥85th percentile who were enrolled in a multidisciplinary pediatric weight management clinic from 2005-2010. Demographic, anthropometric, lifestyle, and cardiometabolic data were retrieved by retrospective medical record review. Participants were dichotomized as either MHO or metabolically unhealthy obese (MUO) according to two separate classification systems based on: 1) insulin resistance (IR) and 2) cardiometabolic risk (CR) factors (blood pressure, serum lipids, and glucose). Multivariable logistic regression was used to determine predictors of MHO using odds ratios (ORs) with 95% CIs.

RESULTS

The prevalence of MHO-IR was 31.5% (n = 57 of 181) and MHO-CR was 21.5% (n = 39 of 181). Waist circumference (OR 0.33 [95% CI 0.18-0.59]; P = 0.0002) and dietary fat intake (OR 0.56 [95% CI 0.31-0.95]; P = 0.04) were independent predictors of MHO-IR; moderate-to-vigorous physical activity (OR 1.80 [95% CI 1.24-2.62]; P = 0.002) was the strongest independent predictor of MHO-CR.

CONCLUSIONS

Up to one in three children with obesity can be classified as MHO. Depending on the definition, adiposity and lifestyle behaviors both play important roles in predicting MHO status. These findings can inform for whom health services for managing pediatric obesity should be prioritized, especially in circumstances when boys and girls present with CR factors.

Levels and patterns of objectively-measured physical activity volume and intensity distribution in UK adolescents: the ROOTS study

BACKGROUND

Few studies have quantified levels of habitual physical activity across the entire intensity range. We aimed to describe variability in total and intensity-specific physical activity levels in UK adolescents across gender, socio-demographic, temporal and body composition strata.

METHODS

Physical activity energy expenditure and minutes per day (min/d) spent sedentary and in light, moderate, and vigorous intensity physical activity were assessed in 825 adolescents from the ROOTS study (43.5% boys; mean age 15.0 ± 0.30 years), by 4 days of individually calibrated combined heart rate and movement sensing. Measurement days were classified as weekday or weekend and according to the three school terms: summer (April-July), autumn (September-December), and spring (January-March). Gender and age were self-reported and area-level SES determined by postcode data. Body composition was measured by anthropometry and bio-electrical impedance. Variability in physical activity and sedentary time was analysed by linear multilevel modelling, and logistic multilevel regression was used to determine factors associated with physical inactivity (<60 min moderate-to-vigorous intensity physical activity/d).

RESULTS

During awake hours (15.8 ± 0.9 hrs/d), adolescents primarily engaged in light intensity physical activity (517 min/d) and sedentary time (364 min/d). Boys were consistently more physically active and less sedentary than girls, but gender differences were smaller at weekends, as activity levels in boys dropped more markedly when transitioning from weekday to weekend. Boys were more sedentary on both weekend days compared to during the week, whereas girls were more sedentary on Sunday but less sedentary on Saturday. In both genders light intensity physical activity was lower in spring, while moderate physical activity was lower in autumn and spring terms, compared to the summer term; sedentary time was also higher in spring than summer term. Adolescents with higher fatness engaged in less vigorous intensity physical activity. Factors associated with increased odds of physical inactivity were female gender, both weekend days in boys, and specifically Sunday in girls.

CONCLUSIONS

Physical activity components vary by gender, temporal factors and body composition in UK adolescents. The available data indicate that in adolescence, girls should be the primary targets of interventions designed to increase physical activity levels.

Exercise and insulin resistance in youth: a meta-analysis

BACKGROUND AND OBJECTIVES

The prevalence of obesity and diabetes is increasing among children, adolescents, and adults. Although estimates of the efficacy of exercise training on fasting insulin and insulin resistance have been provided, for adults similar estimates have not been provided for youth. This systematic review and meta-analysis provides a quantitative estimate of the effectiveness of exercise training on fasting insulin and insulin resistance in children and adolescents.

METHODS

Potential sources were limited to peer-reviewed articles published before June 25, 2013, and gathered from the PubMed, SPORTDiscus, Physical Education Index, and Web of Science online databases. Analysis was limited to randomized controlled trials by using combinations of the terms adolescent, child, pediatric, youth, exercise training, physical activity, diabetes, insulin, randomized trial, and randomized controlled trial. The authors assessed 546 sources, of which 4.4% (24 studies) were eligible for inclusion. Thirty-two effects were used to estimate the effect of exercise training on fasting insulin, with 15 effects measuring the effect on insulin resistance. Estimated effects were independently calculated by multiple authors, and conflicts were resolved before calculating the overall effect.

RESULTS

Based on the cumulative results from these studies, a small to moderate effect was found for exercise training on fasting insulin and improving insulin resistance in youth (Hedges' d effect size = 0.48 [95% confidence interval: 0.22-0.74], P < .001 and 0.31 [95% confidence interval: 0.06-0.56], P < .05, respectively).

CONCLUSIONS

These results support the use of exercise training in the prevention and treatment of type 2 diabetes.

Physical activity among Norwegian adolescents--a multilevel analysis of how place of residence is associated with health behaviour: the Young-HUNT study

Introduction

The purpose of this article is to investigate whether and to what degree participation in physical activity among adolescents is associated with area economic deprivation in the municipality where they live. In the study we took account of aggregated informal social capital at the municipality level and compositional effects due to spatial concentration of individual variables known to be associated with physical activity. These include informal social participation, participation in other cultural activities, and family affluence.

Methods

The study was based on a secondary analysis of data from the Norwegian HUNT study and municipality characteristics from the Norwegian Social Science Data Service ‘Commune Database’ from 2006. The sample consisted of 8114 adolescents whose ages ranged from 13 to 19. The explanatory power of the independent variables on the dependent variable was assessed using a multilevel analysis in which individuals comprised the first level and were nested within the municipality level.

Results

The average level of physical activity was not negatively associated with the level of area economic deprivation when we adjusted for informal social participation at the community level. Adjusting for area economic deprivation, we found that informal social participation at the community level was associated with a higher level of participation in physical activity at p< .01.

Conclusion

For adolescents in a given municipality, informal social participation is more strongly associated with a higher level of physical activity than the degree of area economic deprivation. This finding supports our social capital hypothesis, which states that the amount of social capital is strengthening the individual’s ability to take part in physical activity.

Longitudinal patterns of physical activity in children aged 8 to 12 years: the LOOK study

BACKGROUND

Data on longitudinal monitoring of daily physical activity (PA) patterns in youth over successive years is scarce but may provide valuable information for intervention strategies aiming to promote PA.

METHODS

Participants were 853 children (starting age ~8 years) recruited from 29 Australian elementary schools. Pedometers were worn for a 7-day period each year over 5 consecutive years to assess PA volume (steps per day) and accelerometers were worn concurrently in the final 2 years to assess PA volume (accelerometer counts (AC) per day), moderate and vigorous PA (MVPA), light PA (LPA) and sedentary time (SED). A general linear mixed model was used to examine daily and yearly patterns.

RESULTS

A consistent daily pattern of pedometer step counts, AC, MVPA and LPA emerged during each year, characterised by increases on school days from Monday to Friday followed by a decrease on the weekend. Friday was the most active and Sunday the least active day. The percentage of girls and boys meeting international recommendations of 11,000 and 13,000 steps/day respectively on a Monday, Friday and Sunday were 36%, 50%, 21% for boys and 35%, 45%, 18% for girls. The equivalent percentages meeting the recommended MVPA of >60 min/day on these days were 29%, 39%, 16% for boys and 15%, 21%, 10% for girls. Over the 5 years, boys were more active than girls (mean steps/day of 10,506 vs 8,750; p<0.001) and spent more time in MVPA (mean of 42.8 vs 31.1 min/day; p<0.001). Although there was little evidence of any upward or downward trend in steps/day from age 8 to 12 years, there was a trend toward lower MVPA, LPA and a corresponding increase in SED from age 11 to 12 years.

CONCLUSION

A weekly pattern of PA occurred in children as young as age 8 on a day by day basis; these patterns persisting through to age 12. In addition to supporting previous evidence of insufficient PA in children, our data, in identifying the level and incidence of insufficiency on each day of the week, may assist in the development of more specific strategies to increase PA in community based children.

The association of anthropometric indices in adolescence with the occurrence of the metabolic syndrome in early adulthood: Tehran Lipid and Glucose Study (TLGS)

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Little is known about the predictive ability of anthropometric indices in adolescence for prediction of early adulthood metabolic syndrome (MetS). There are controversies about the predictive power of body mass index (BMI) vs. waist circumference (WC) for prediction of MetS in late adolescence; some of the studies did not support the need to measure WC in mid-adolescence, in addition to BMI; on the other hand, some other studies proposed either similar predictability or superiority of WC to identify MetS in late adolescence.

WHAT THIS STUDY ADDS

This is the first study to evaluate the adolescent anthropometric indices in relation to early adulthood MetS incidence one decade later in the Middle East region. There is an important sex difference regarding the incidence of MetS in Tehranian adolescents. It is interesting to know that all anthropometric indices in the pubertal age group (11-14 years) had better predictive ability compared to late-pubertal (15-18 years) adolescents. In addition, adolescent abdominal obesity surrogates, including WC and waist-to-height ratio, predicted adulthood MetS better than BMI in boys. It seems that WC had an independent role beyond BMI in identification of adulthood MetS in Tehranian boys (11-18 years old).

BACKGROUND

Little is known about the predictive ability of anthropometric indices in adolescence for prediction of early adulthood metabolic syndrome (MetS).

OBJECTIVE

Our purpose was to explore incidence of MetS and the optimal anthropometric indicator to predict early adulthood MetS in Tehranian adolescents.

METHODS

Using data from the population-based, prospective, Tehran Lipid and Glucose Study, the utility of four anthropometric indices of adolescents in predicting early adulthood MetS (2009 Joint Scientific Statement definition) was examined among 1100 participants, aged 11-18 years, who were free of MetS at baseline, during a mean of 10.2 years of follow-up.

RESULTS

The cumulative incidence of MetS was 25.5% (95% confidence interval [CI]: 21.8-29.2%) for young men and 1.8% (95% CI: 0.6-3%) for young women. In boys, waist circumference (WC) had the highest odds ratio (OR) for the MetS risk, followed by waist-to-height ratio (WHtR). Adjusting body mass index (BMI) in addition to WC did not change the results in the 11-14-year age group (OR for WC: 2.28 [1.64-3.16] without BMI adjustment vs. 1.98 [1.05-3.73] with BMI adjustment), suggesting that WC may predict MetS risk beyond BMI. None of the anthropometric indices were found to have significant associations with subsequent MetS risk in girls.

CONCLUSIONS

Measures of abdominal obesity including WHtR and WC predicted early adulthood MetS better than BMI in Tehranian male adolescents (11-18 years old).

Dietary and lifestyle quality indices with/without physical activity and markers of insulin resistance in European adolescents: the HELENA study

Emerging data indicate that higher levels of insulin resistance (IR) are common among children and adolescents and are related to cardiometabolic risk; therefore, IR requires consideration early in life. In addition, there is a lack of conclusive evidence regarding the role of dietary nutrients on IR. The Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study (HELENA-CSS) was conducted in European adolescents aged 12·5–17·5 years. A total of 637 participants with valid homeostasis model assessment (HOMA) index data and who completed at least a 2 d 24 h dietary recall were included in the study (60% of the total HELENA-CSS sample). There were two dietary indices calculated, with the only difference between them being the inclusion or not of physical activity (PA). Markers of IR such as HOMA and the quantitative insulin sensitivity check index (QUICKI) were calculated. Pubertal status, BMI and cardiorespiratory fitness (CRF) were measured as potential confounders. The dietary index including PA was inversely associated with HOMA and directly with the QUICKI in females, but not in males, after adjusting for pubertal status, centre, BMI and CRF. In conclusion, the present study indicates that considering PA as part of the dietary index is of relevance as the resulted index is inversely related to IR independently of potential confounders including CRF. Overall, these findings suggest that intervention studies aimed at preventing IR in young people should focus on increasing the quality of the diet and also on including an optimal PA level in healthy adolescents.

The impact of ethnicity on objectively measured physical activity in children

Obesity and obesity-related diseases (cardiovascular disease/metabolic risk factors) are experienced differently in individuals from different ethnic backgrounds, which originate in childhood. Physical activity is a modifiable risk factor for obesity and related diseases. Both physical activity and metabolic risk factors track to adulthood, and thus understanding the physical activity patterns in children from different ethnic backgrounds is important. Given the limitations of self-report measures in children, this study provides a review of studies which have objectively measured physical activity patterns in children from different ethnic backgrounds. From a total of 16 studies, it can be concluded that physical activity does seem to vary amongst the ethnic groups especially South Asian and Black compared to White EU (European Union). The findings are less consistent for Hispanic/Mexican American children. However, there are several methodological limitations which need to be considered in future studies. Firstly, there is a need for consistency in the measurement of physical activity. Secondly, there are a range of complex factors such as socioeconomic status and body composition which affect both physical activity and ethnicity. Studies have failed to account for these differences limiting the ability to generalise that ethnicity is an independent risk factor for physical activity.

Epigenetic manifestation of metabolic syndrome and dietary management

SIGNIFICANCE

Metabolic syndrome constitutes a group of disorders such as insulin resistance, hypertension, and hypertriglyceridemia, predisposing an individual to risk factors such as cardiovascular disease, diabetes, obesity, and dyslipidemia. A majority of these diseases are influenced by the environmental factors, nutrient uptake, and genetic profile of an individual that together dysregulate gene function. These genetic and nongenetic factors are reported to introduce epigenetic cues that modulate the gene function which is inherited by the offspring.

RECENT ADVANCES

Considering the epigenetic modulation of the metabolic disorders, nutrigenomics has been distinctly categorized as a branch that deals with modulatory effect of nutrients on metabolic disorders and disease progression by supplementing the individuals with key nutrient-enriched diets which are derived from plant and animal sources.

CRITICAL ISSUES

Nutritional components of the diet regulate the metabolic health of an individual either by controlling the expression of some key genes related to metabolic pathways or by modulating the epigenetic events on such genes. The present article discusses various metabolic disorders in detail and the effect of nutrients on the specific genes causing those disorders. We also highlight the molecular mechanisms of some metabolic disorders through epigenetic modifications and possible therapeutic interventions.

FUTURE DIRECTIONS

With the advent of high-throughput technologies and epigenetic modulation of the metabolic disorders, an altered epigenetic code that is programmed due to improper nutrients can be reverted back by supplementing the diet with various plant-derived compounds. The implication of small molecular drugs is also of utmost significance for challenging the metabolic disorders.

Gender Differences Time Trends for Metabolic Syndrome and Its Components among Tehranian Children and Adolescents

Aims. To investigate the trend of metabolic syndrome and its components in Tehran children and adolescents during a median followup of 6.6 years. Methods. Data from 1999-2001 (phase I), 2002-2005 (phase II), and 2006-2008 (phase III) of the Tehran, Lipid and Glucose Study were analyzed (n = 5439; age 6-18 years) for the trend of metabolic syndrome (MetS) and its components. General estimation equation (GEE) models were used to analyze this correlated data. Results. The crude prevalence of MetS for boys at baseline was 13.2%, which increased to 16.4% in the third phase. In girls, the prevalence of Mets decreased from 11.8% at baseline to 6% during followup. The odd ratios (OR) of obesity over the whole study period were raised in both sexes. The OR of abdominal obesity increased significantly in boys, but no change was observed in girls. No significant OR was observed in boys, while OR for MetS was shown to have a decreasing trend in girls during the followup. In the three time points, the ORs of MetS decreased significantly in girls but no significant difference was observed in boys. Conclusion. Inspite of increasing trend for obesity in both sexes, the trend of MetS decreased in girls and was relatively stable in boys, in Tehranian children, and adolescents.

Physical activity promotion in the preschool years: a critical period to intervene

The primary aim of this paper is to provide a rationale for the necessity of intervening with a physical activity intervention in the preschool years and why the daycare environment is amenable to such intervention. We also review the prevalence of physical activity, sedentary behaviour and obesity in the preschool population and the impact that these lifestyle behaviours and conditions have on the health of preschool aged children, as secondary objectives. Moreover we discuss implications for intervention and research using a "lessons learned" model based on our research team's experience of conducting a randomized controlled trial aimed at increasing physical activity, reducing sedentary behaviour and improving motor skill development and body composition in preschoolers. Lastly, we make conclusions based on the literature and highlight issues and directions that need to be addressed in future research in order to maximize health promotion and chronic disease prevention in the pediatric population.

Do the interactions between glucocorticoids and sex hormones regulate the development of the metabolic syndrome?

The metabolic syndrome is basically a maturity-onset disease. Typically, its manifestations begin to flourish years after the initial dietary or environmental aggression began. Since most hormonal, metabolic, or defense responses are practically immediate, the procrastinated response do not seem justified. Only in childhood, the damages of the metabolic syndrome appear with minimal delay. Sex affects the incidence of the metabolic syndrome, but this is more an effect of timing than absolute gender differences, females holding better than males up to menopause, when the differences between sexes tend to disappear. The metabolic syndrome is related to an immune response, countered by a permanent increase in glucocorticoids, which keep the immune system at bay but also induce insulin resistance, alter the lipid metabolism, favor fat deposition, mobilize protein, and decrease androgen synthesis. Androgens limit the operation of glucocorticoids, which is also partly blocked by estrogens, since they decrease inflammation (which enhances glucocorticoid release). These facts suggest that the appearance of the metabolic syndrome symptoms depends on the strength (i.e., levels) of androgens and estrogens. The predominance of glucocorticoids and the full manifestation of the syndrome in men are favored by decreased androgen activity. Low androgens can be found in infancy, maturity, advanced age, or because of their inhibition by glucocorticoids (inflammation, stress, medical treatment). Estrogens decrease inflammation and reduce the glucocorticoid response. Low estrogen (infancy, menopause) again allow the predominance of glucocorticoids and the manifestation of the metabolic syndrome. It is postulated that the equilibrium between sex hormones and glucocorticoids may be a critical element in the timing of the manifestation of metabolic syndrome-related pathologies.

Maturity negates the gender-related difference in physical activity among youth. Is this equally justified whatever the accelerometer cut-off point used?

OBJECTIVES

To examine the consistency in findings about the influence of maturity on the gender-difference in moderate-to-vigorous physical activity (MVPA) of children using different cut-off points for MVPA.

DESIGN

Cross-sectional observation study.

METHODS

The sample involved 253 children (139 boys) of 9.9±0.9 years. Their physical activity was evaluated using an Actigraph accelerometer. The biological age of children was determined with their estimated age at the peak height velocity, and maturity categories were gender-specific defined.

RESULTS

Boys spent more time in MVPA than girls (P<0.0001), and no maturity-related differences were obtained on the whole sample. It was only among boys that differences were found between maturity groups with cut-off points of 3000 cpm (P=0.034), 3200 cpm (P=0.024), and 3600 cpm (P=0.011). At a given maturity level, boys spent significantly more time in MVPA than girls, except with the cut-off point of 1000 cpm (P=0.07). There were higher proportions of sufficiently active boys, but significances were reached only with cut-off points above 3000 cpm. There were no maturity-related differences in the proportion of sufficiently active children as MVPA was computed using cut-off points of 1000 cpm, 2000 cpm or 3000 cpm.

CONCLUSIONS

The role of maturity in the gender-difference in MVPA seems unclear as one another cut-off point is used among children. Even if a relatively greater consistency was found with the three cut-off points above 3000 cpm, data comparison may require a conversion system until a consensus is reached about the exact value to be used among children.