Associations of obesity phenotypes with weight change, cardiometabolic benefits, and type 2 diabetes incidence during a lifestyle intervention: results from the PREVIEW study.

BACKGROUND/OBJECTIVES: Some individuals with overweight/obesity may be relatively metabolically healthy (MHO) and have a lower risk of cardiovascular disease than those with metabolically unhealthy overweight/obesity (MUO). We aimed to compare changes in body weight and cardiometabolic risk factors and type 2 diabetes incidence during a lifestyle intervention between individuals with MHO vs MUO. METHODS: This post-hoc analysis included 1012 participants with MHO and 1153 participants with MUO at baseline in the randomized trial PREVIEW. Participants underwent an eight-week low-energy diet phase followed by a 148-week lifestyle-based weight-maintenance intervention. Adjusted linear mixed models and Cox proportional hazards regression models were used. RESULTS: There were no statistically significant differences in weight loss (%) between participants with MHO vs MUO over 156 weeks. At the end of the study, weight loss was 2.7% (95% CI, 1.7%-3.6%) in participants with MHO and 3.0% (2.1%-4.0%) in those with MUO. After the low-energy diet phase, participants with MHO had smaller decreases in triglyceride (mean difference between MHO vs MUO 0.08 mmol·L-1 [95% CI, 0.04-0.12]; P < 0.001) but similar reductions in fasting glucose and HOMA-IR than those with MUO. However, at the end of weight maintenance, those with MHO had greater reductions in triglyceride (mean difference -0.08 mmol·L-1 [-0.12--0.04]; P < 0.001), fasting glucose, 2-hour glucose (difference -0.28 mmol·L-1 [-0.41--0.16]; P < 0.001), and HOMA-IR than those with MUO. Participants with MHO had smaller decreases in diastolic blood pressure and HbA1c and greater decreases in HDL cholesterol after weight loss than those with MUO, whereas the statistically significant differences disappeared at the end of weight maintenance. Participants with MHO had lower 3-year type 2 diabetes incidence than those with MUO (adjusted hazard ratio 0.37 [0.20-0.66]; P < 0.001). CONCLUSIONS: Individuals with MUO had greater improvements in some cardiometabolic risk factors during the low-energy diet phase, but had smaller improvements during long-term lifestyle intervention than those with MHO.

Socio-economic factors, mood, primary care utilization, and quality of life as predictors of intervention cessation and chronic stress in a type 2 diabetes prevention intervention (PREVIEW Study).

BACKGROUND: Sedentary lifestyle and unhealthy diet combined with overweight are risk factors for type 2 diabetes (T2D). Lifestyle interventions with weight-loss are effective in T2D-prevention, but unsuccessful completion and chronic stress may hinder efficacy. Determinants of chronic stress and premature cessation at the start of the 3-year PREVIEW study were examined. METHODS: Baseline Quality of Life (QoL), social support, primary care utilization, and mood were examined as predictors of intervention cessation and chronic stress for participants aged 25 to 70 with prediabetes (n = 2,220). Moderating effects of sex and socio-economic status (SES) and independence of predictor variables of BMI were tested. RESULTS: Participants with children, women, and higher SES quitted intervention earlier than those without children, lower SES, and men. Lower QoL, lack of family support, and primary care utilization were associated with cessation. Lower QoL and higher mood disturbances were associated with chronic stress. Predictor variables were independent (p ≤ .001) from BMI, but moderated by sex and SES. CONCLUSIONS: Policy-based strategy in public health should consider how preventive interventions may better accommodate different individual states and life situations, which could influence intervention completion. Intervention designs should enable in-built flexibility in delivery enabling response to individual needs. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01777893.

Clusters of Activity-Related Social and Physical Home Environmental Factors and Their Association With Children's Home-Based Physical Activity and Sitting.

PURPOSE: Understanding which physical activity (PA) and sedentary behavior correlates cluster in children is important, particularly in the home, where children spend significant time. Therefore, this study aimed to assess clustering of physical and social activity-related factors at home, and whether these clusters are related to home-based sitting and PA in children. A secondary aim was to explore whether the clusters were associated with child, parent, and family characteristics. METHODS: Altogether, 235 children (55% girls, mean age = 10.2 [0.7] y) and their parents took part. Physical (eg, PA and electronic media equipment, house and garden size, layout) and social (eg, activity preferences, priorities, parental rules) home environmental factors were obtained via the HomeSPACE-II audit and self-report, respectively. Principal component analysis was used to identify clusters of physical and social environmental factors. Backward regression analysis and partial correlations were used to examine relationships between clusters, children's device-measured home-based activity behaviors, and background characteristics. RESULTS: The findings show that physical and social environment activity-related factors at home cluster. The clusters were associated with several background characteristics, with socioeconomic factors appearing to be particularly influential. The clusters were also associated with home-based activity behaviors in the hypothesized directions. CONCLUSION: Interventions which target clusters of social and physical factors at home, especially among low-socioeconomic status families, are warranted.

Age- and sex-specific effects of a long-term lifestyle intervention on body weight and cardiometabolic health markers in adults with prediabetes: results from the diabetes prevention study PREVIEW.

AIMS/HYPOTHESIS: Lifestyle interventions are the first-line treatment option for body weight and cardiometabolic health management. However, whether age groups or women and men respond differently to lifestyle interventions is under debate. We aimed to examine age- and sex-specific effects of a low-energy diet (LED) followed by a long-term lifestyle intervention on body weight, body composition and cardiometabolic health markers in adults with prediabetes (i.e. impaired fasting glucose and/or impaired glucose tolerance). METHODS: This observational study used longitudinal data from 2223 overweight participants with prediabetes in the multicentre diabetes prevention study PREVIEW. The participants underwent a LED-induced rapid weight loss (WL) period followed by a 3 year lifestyle-based weight maintenance (WM) intervention. Changes in outcomes of interest in prespecified age (younger: 25-45 years; middle-aged: 46-54 years; older: 55-70 years) or sex (women and men) groups were compared. RESULTS: In total, 783 younger, 319 middle-aged and 1121 older adults and 1503 women and 720 men were included in the analysis. In the available case and complete case analyses, multivariable-adjusted linear mixed models showed that younger and older adults had similar weight loss after the LED, whereas older adults had greater sustained weight loss after the WM intervention (adjusted difference for older vs younger adults -1.25% [95% CI -1.92, -0.58], p<0.001). After the WM intervention, older adults lost more fat-free mass and bone mass and had smaller improvements in 2 h plasma glucose (adjusted difference for older vs younger adults 0.65 mmol/l [95% CI 0.50, 0.80], p<0.001) and systolic blood pressure (adjusted difference for older vs younger adults 2.57 mmHg [95% CI 1.37, 3.77], p<0.001) than younger adults. Older adults had smaller decreases in fasting and 2 h glucose, HbA1c and systolic blood pressure after the WM intervention than middle-aged adults. In the complete case analysis, the above-mentioned differences between middle-aged and older adults disappeared, but the direction of the effect size did not change. After the WL period, compared with men, women had less weight loss (adjusted difference for women vs men 1.78% [95% CI 1.12, 2.43], p<0.001) with greater fat-free mass and bone mass loss and smaller improvements in HbA1c, LDL-cholesterol and diastolic blood pressure. After the WM intervention, women had greater fat-free mass and bone mass loss and smaller improvements in HbA1c and LDL-cholesterol, while they had greater improvements in fasting glucose, triacylglycerol (adjusted difference for women vs men -0.08 mmol/l [-0.11, -0.04], p<0.001) and HDL-cholesterol. CONCLUSIONS/INTERPRETATION: Older adults benefited less from a lifestyle intervention in relation to body composition and cardiometabolic health markers than younger adults, despite greater sustained weight loss. Women benefited less from a LED followed by a lifestyle intervention in relation to body weight and body composition than men. Future interventions targeting older adults or women should take prevention of fat-free mass and bone mass loss into consideration. CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NCT01777893.

Homes became the "everything space" during COVID-19: impact of changes to the home environment on children's physical activity and sitting.

BACKGROUND: During the 2020 UK COVID-19 lockdown restrictions, children spent almost all of their time at home, which had a significant influence on their physical activity (PA) and sedentary behaviour. This study aimed to: 1) determine changes to the social and physical environment at home and children's home-based sitting, PA, standing and sitting breaks as a result of the COVID-19 restrictions; and 2) examine associations between changes at home and children's movement behaviours. METHODS: One hundred and two children had their PA and sitting, standing and sitting breaks at home objectively measured pre-COVID-19 and during the first COVID-19 lockdown (June-July 2020). Children's parents (n = 101) completed an audit of their home physical environment and a survey on the home social environment at both time points. Changes in the home physical and social environment and behavioural outcomes were assessed using Wilcoxon signed ranked tests, paired t-tests, or chi-square. Repeated linear regression analyses examined associations between changes in homes and changes in the home-based behavioural outcomes. RESULTS: During COVID-19, households increased the amount of seated furniture and electronic media equipment at home. The number of books and PA equipment decreased and fewer parents enforced a screen-time rule. Children's preference for physical activities and socialising at home decreased. Time at home and sitting at home increased during COVID-19, whilst PA, standing and sitting breaks decreased. Both MVPA and TPA were positively associated with child preference for PA, and negatively associated with attending school. Sitting was negatively associated with child preference for PA and child preference for socialising at home. Media equipment was negatively associated with sitting breaks, whilst PA equipment was positively associated with standing. CONCLUSION: The COVID-19 restrictions forced children to spend almost all their time at home. Children's PA, standing, and sitting breaks at home declined during the restrictions, while sitting increased. Mostly negative changes occurred in homes, some of which impacted children's behaviours at home. To avoid the changes persisting post-lockdown, interventions are needed to reset and promote children's PA and discourage prolonged sitting time.

Foreign allometric exponents adequately normalize isokinetic knee extension strength to identify muscle weakness and mobility limitation in Portuguese older adults: a cross-sectional study.

BACKGROUND: Identifying muscle weakness is challenging, because the reduction of strength with aging does not depend only on sarcopenia, but also on sensorimotor deficits. Nevertheless, this identification is improved by adjusting muscle strength allometrically, by removing the influence of body size. However, the effectiveness of foreign models to normalize these (dys)functionalities is not yet tested. This study aimed to compare and apply foreign allometric exponents for normalizing isokinetic knee extension strength in Portuguese older adults to identify muscle weakness/mobility limitation. Additionally, to attest any populational difference, data of these people and Brazilian older adults were compared METHODS: This is a cross-sectional study encompassing 226 Portuguese (n = 132) and Brazilian (n = 94) older adults. Mobility limitation (six-minute walk test, at lowest quartile), lower limb strength (knee extension isokinetic strength at 60º/s), and body dimensions measures were taken. Foreign allometric exponents (b) were used to normalize Portuguese strength (strength/body-size variablesb). Non-normalized and normalized strength were compared (ROC) to generate the most accurate cut-point for identifying muscle weakness/mobility limitation. RESULTS: Older Portuguese men and women had better mobility than their Brazilian counterparts. Older Portuguese women had superior muscle strength to Brazilian women. Normalization from 11 foreign models removed the influence of body size on muscle strength, with a negligible correlation (r ≤ 0.30). In contrast to the non-normalized strength, the normalized strength cut-off points were sufficiently accurate (AUC ≥ 0.70) to avoid identifying false-negative cases of weakness/mobility limitation. CONCLUSIONS: Portuguese older women were stronger and had superior functional capacity compared to Brazilian ones. Normalized foreign models improved the accuracy in identifying muscle weakness/mobility limitation in Portuguese older adults. The isokinetic knee extension muscle strength normalized, even using foreign allometric exponents, should be better than no adjustment.

Associations between swimming & cycling abilities and fitness in 9-11 year old boys and girls.

The associations between swimming and cycling abilities and fitness levels in 9-11-year-old children were examined. A cross-sectional study involving 2258 children (50.7% boys; aged 10.52 ± 0.6 years) from 33 schools across Wales, participated in Swan/BridgeLinx health, fitness, and lifestyle programmes between 2013-2019. Health and fitness data were collected; namely body composition, cardiorespiratory fitness, muscular strength, flexibility, power, and speed using standardised measures. Children completed an online survey collecting data on swimming and cycling abilities and sports club attendance. Multivariate multilevel regressions were used to examine the associations between measures. The ability to swim and cycle was significantly (p < 0.05) associated with all components of fitness when accounting for age, body mass index (BMI), deprivation, gender, and sports club attendance. Boys outperformed girls with significant interactions between swimming, cycling and cardiorespiratory fitness for gender by swim (p = 0.001) and gender by cycle (p = 0.015). The gender by cycle interaction significantly predicted grip strength and power (p < 0.05). Swimming and cycling are important "milestones" in the journey of motor development and are associated with higher levels of fitness. These activities should be promoted to allow for an optimal development of motor skills, fitness, and health.

The PREVIEW intervention study: Results from a 3-year randomized 2 x 2 factorial multinational trial investigating the role of protein, glycaemic index and physical activity for prevention of type 2 diabetes.

AIM: To compare the impact of two long-term weight-maintenance diets, a high protein (HP) and low glycaemic index (GI) diet versus a moderate protein (MP) and moderate GI diet, combined with either high intensity (HI) or moderate intensity physical activity (PA), on the incidence of type 2 diabetes (T2D) after rapid weight loss. MATERIALS AND METHODS: A 3-year multicentre randomized trial in eight countries using a 2 x 2 diet-by-PA factorial design was conducted. Eight-week weight reduction was followed by a 3-year randomized weight-maintenance phase. In total, 2326 adults (age 25-70 years, body mass index ≥ 25 kg/m2 ) with prediabetes were enrolled. The primary endpoint was 3-year incidence of T2D analysed by diet treatment. Secondary outcomes included glucose, insulin, HbA1c and body weight. RESULTS: The total number of T2D cases was 62 and the cumulative incidence rate was 3.1%, with no significant differences between the two diets, PA or their combination. T2D incidence was similar across intervention centres, irrespective of attrition. Significantly fewer participants achieved normoglycaemia in the HP compared with the MP group (P < .0001). At 3 years, normoglycaemia was lowest in HP-HI (11.9%) compared with the other three groups (20.0%-21.0%, P < .05). There were no group differences in body weight change (-11% after 8-week weight reduction; -5% after 3-year weight maintenance) or in other secondary outcomes. CONCLUSIONS: Three-year incidence of T2D was much lower than predicted and did not differ between diets, PA or their combination. Maintaining the target intakes of protein and GI over 3 years was difficult, but the overall protocol combining weight loss, healthy eating and PA was successful in markedly reducing the risk of T2D. This is an important clinically relevant outcome.

The AHK-Wales Report Card 2018: Policy Measures - is it possible to 'score' qualitative data?

Comprehensive and meaningful policy analysis in the field of physical activity is difficult, not least because of the variable influence of other policy domains. However, in 2011 a Policy Assessment Tool (PAT) was developed by members of the WHO European Network for the Promotion of Health-Enhancing Physical Activity (HEPA Europe) and tested in several different countries. In 2014, Wales joined a global initiative, active healthy kids (AHK) Global Alliance, that supported the development of country level 'Report Cards' scoring a range of indicators that influence physical activity amongst children and young people, one of which was labelled 'Government Strategies and Investments'. For the first two Report Cards this indicator and its associated 'score' was informed subjectively by expert consensus. In 2018, it was decided to utilize the Policy Audit Tool Version 2 (PAT v2) developed by HEPA Europe to aid analysis and to develop and test a scoring rubric aligned to the tool. The subsequent process indicated that the tool could be applied and translated into a 'grade' that could be used in conjunction with the other indicators of the AHK Report Card to generate overall Report Card grades. The use of both the HEPA PAT v2 and the scoring rubric offers an opportunity to provide greater consistency and potential for developing both comparative and trend data when assessing policy impact on physical activity in children and young people. These tools should be utilized by the AHK Global Alliance in future Report Cards.

Lifestyle Behaviors Associated With Body Fat Percent in 9- to 11-Year-Old Children.

PURPOSE: To examine (1) associations between body fat percent (BF) and lifestyle behaviors in children aged 9-11 years and (2) the consistency of these associations over a 10-year period. METHODS: In this repeat, cross-sectional study, 15,977 children aged 9-11 years completed an anthropometric assessment and the SportsLinx Lifestyle survey between 2004 and 2013. Body fat was estimated according to the sum of the triceps and subscapular skinfold measurements. Multilevel models were utilized to examine associations between BF and responses to the lifestyle survey while controlling for known covariates. RESULTS: Lifestyle behaviors explained 8.6% of the total variance in body fat. Specifically, negative associations were found between BF and active transport to school ( ß = -0.99 [0.19], P < .001), full-fat milk (-0.07 [0.15], P < .001), and sweetened beverage consumption (-0.40 [0.15], P = .007). Relative to the reference group of ≤8:00 PM, later bedtime was positively associated with BF: 8:00 to 8:59 PM ( ß = 1.60 [0.26], P < .001); 9:00 to 10:00 PM ( ß = 1.04 [0.24], P < .001); ≥10:00 PM ( ß = 1.18 [0.30], P < .001). Two-way interactions revealed opposing associations between BF and the consumption of low-calorie beverages for boys ( ß = 0.95 [0.25], P < .001) and girls ( ß = -0.85 [0.37], P = .021). There was no significant change in these associations over a 10-year period. CONCLUSIONS: In this population-level study covering a decade of data collection, lifestyle behaviors were associated with BF. Policies and interventions targeting population-level behavior change, such as active transport to school, sleep time, and consumption of full-fat milk, may offer an opportunity for improvements in BF.

Are individual and social factors specific to the home associated with children's behaviour and physical environment at home.

This study used linear regression analyses to investigate the influence of parent-reported home-specific social and individual factors on: (i) 235 children's home-based objectively measured overall sitting time, breaks in sitting, and PA, and; (ii) the home physical environment via an audit. Parental importance assigned to active play for children was positively associated with PA equipment (accessibility and availability), as well as light physical activity (LPA) and sitting breaks on both weekdays and weekend days. Parental preference for being active at home and limits on screen-time were associated with less household media equipment and portable media equipment, respectively. Greater parental importance placed on playing electronic games/using computers for fun was associated with less LPA and more sitting on weekdays. Further, children who preferred being sedentary sat more and engaged in less moderate-vigorous physical activity (MVPA) on weekdays. Parental and child preferences and priorities, as well as parental rules for activity at home, were associated with children's home-based sitting and PA, especially on weekdays. Such factors were also associated with the physical environment in the expected directions. The findings suggest interventions need to target social and individual factors, alongside adapting the physical environment to create homes more promotive of physical activity.

Compositional analysis of the associations between 24-h movement behaviours and cardio-metabolic risk factors in overweight and obese adults with pre-diabetes from the PREVIEW study: cross-sectional baseline analysis.

BACKGROUND: Physical activity, sedentary time and sleep have been shown to be associated with cardio-metabolic health. However, these associations are typically studied in isolation or without accounting for the effect of all movement behaviours and the constrained nature of data that comprise a finite whole such as a 24 h day. The aim of this study was to examine the associations between the composition of daily movement behaviours (including sleep, sedentary time (ST), light intensity physical activity (LIPA) and moderate-to-vigorous activity (MVPA)) and cardio-metabolic health, in a cross-sectional analysis of adults with pre-diabetes. Further, we quantified the predicted differences following reallocation of time between behaviours. METHODS: Accelerometers were used to quantify daily movement behaviours in 1462 adults from eight countries with a body mass index (BMI) ≥25 kg·m- 2, impaired fasting glucose (IFG; 5.6-6.9 mmol·l- 1) and/or impaired glucose tolerance (IGT; 7.8-11.0 mmol•l- 1 2 h following oral glucose tolerance test, OGTT). Compositional isotemporal substitution was used to estimate the association of reallocating time between behaviours. RESULTS: Replacing MVPA with any other behaviour around the mean composition was associated with a poorer cardio-metabolic risk profile. Conversely, when MVPA was increased, the relationships with cardiometabolic risk markers was favourable but with smaller predicted changes than when MVPA was replaced. Further, substituting ST with LIPA predicted improvements in cardio-metabolic risk markers, most notably insulin and HOMA-IR. CONCLUSIONS: This is the first study to use compositional analysis of the 24 h movement composition in adults with overweight/obesity and pre-diabetes. These findings build on previous literature that suggest replacing ST with LIPA may produce metabolic benefits that contribute to the prevention and management of type 2 diabetes. Furthermore, the asymmetry in the predicted change in risk markers following the reallocation of time to/from MVPA highlights the importance of maintaining existing levels of MVPA. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01777893).

A cross-sectional study on the deprivation and sex differences in health-related fitness measures in school children.

This study aimed to investigate deprivation and sex differences in selected health-relatedfitness measures in 9-12-year-old children. Data were captured on 3,407 children (49.3% boys; aged 10.5 ± 0.6 years). Cardiorespiratory fitness(20 m multistage shuttle run test; 20 m MSRT), muscular strength (handgrip strength) and body mass index (BMI) were measured. Welsh Index of Multiple Deprivation (WIMD) scores were used to make quintile groups. A two-way Analysis of Variance examined differences in BMI z-score by sex and WIMD quintiles. Two-wayAnalysis of Covariances investigated the effect of sex and WIMD quintiles on grip strength and shuttles achieved in 20 m MSRT, adjusting for BMI z-score and maturation, repectively. Independent of sex, children in the middle quintile had a significantly higher mean BMI z-score (p = 0.029) than their least deprived counterparts. There was a significant increase in grip strength (p = 0.005) and20 m MSRT (boys p < 0.001; girls p = 0.028) between most and least deprived quintiles. Significant differences in 20 m MSRT score were more apparent with decreases in deprivation in boys.Overall, inequalities exist in health-related fitness by sex and deprivation. These results can be used to inform focused services to improve current and future health.

Profiling movement behaviours in pre-school children: A self-organised map approach.

Application of machine learning techniques has the potential to yield unseen insights into movement and permits visualisation of complex behaviours and tangible profiles. The aim of this study was to identify profiles of relative motor competence (MC) and movement behaviours in pre-school children using novel analytics. One-hundred and twenty-five children (4.3 ± 0.5y, 1.04 ± 0.05 m, 17.8 ± 3.2 kg, BMI: 16.2 ± 1.9 kg.m2) took part in this study. Measures included accelerometer-derived 24-h activity, MC (Movement Assessment Battery for Children second edition), height, weight and waist circumference, from which zBMI were derived. Self-Organised Map (SOM) analysis was used to classify participants' profiles and a k-means cluster analysis was used to classify the neurons into larger groups according to the input variables. These clusters were used to describe the individuals' characteristics according to their MC and PA compositions. The SOM analysis indicated five profiles according to MC and PA. One cluster was identified as having both the lowest MC and MVPA (profile 2), whilst profiles 4 and 5 show moderate-high values of PA and MC. We present a novel pathway to profiling complex tenets of human movement and behaviour, which has never previously been implemented in pre-school children, highlighting that the focus should change from obesity monitoring, to "moving well".Abbreviations: MC: Motor competence; PA: Physical activity; MVPA: Moderate-to-vigorous physical activity; SOM: Self-organized map; BMI: Body mass index; MABC2: Movement assessment battery for children 2nd edition; MANOVA: Multiple analysis of variance.

Asthma, body mass and aerobic fitness, the relationship in adolescents: The exercise for asthma with commando Joe's® (X4ACJ) trial.

Although an association has been suggested between asthma, obesity, fitness and physical activity, the relationship between these parameters remains to be elucidated in adolescents. Six-hundred and sixteen adolescents were recruited (334 boys; 13.0 ± 1.1years; 1.57 ± 0.10m; 52.6 ± 12.9kg), of which 155 suffered from mild-to-moderate asthma (78 boys). Participants completed a 20-metre shuttle run test, lung function and 7-day objective physical activity measurements and completed asthma control and quality of life questionnaires. Furthermore, 69 adolescents (36 asthma; 21 boys) completed an incremental ramp cycle ergometer test. Although participants with asthma completed significantly fewer shuttle runs than their peers, peak V̇O2 did not differ between the groups. However, adolescents with asthma engaged in less physical activity (53.9 ± 23.5 vs 60.5 ± 23.6minutes) and had higher BMI (22.2 ± 4.8 vs 20.4 ± 3.7kg·m-2), than their peers. Whilst a significant relationship was found between quality of life and cardiorespiratory fitness according to peak V̇O2, only BMI was revealed as a significant predictor of asthma status. The current findings highlight the need to use accurate measures of cardiorespiratory fitness rather than indirect estimates to assess the influence of asthma during adolescence. Furthermore, the present study suggests that BMI and fitness may be key targets for future interventions seeking to improve asthma quality of life.

PREVIEW (Prevention of Diabetes Through Lifestyle Intervention and Population Studies in Europe and Around the World) study in children aged 10 to 17 years: Design, methods and baseline results.

Insulin resistance (IR) in adolescence is associated with type 2 diabetes mellitus [T2DM]. The PREVIEW (Prevention of Diabetes Through Lifestyle Intervention and Population Studies in Europe and Around the World) study assessed the effectiveness of a high-protein, low-glycaemic-index diet and a moderate-protein, moderate-glycaemic-index diet to decrease IR in insulin-resistant children who were overweight or obese. Inclusion criteria were age 10 to 17 years, homeostatic model assessment of IR (HOMA-IR) ≥2.0 and overweight/obesity. In 126 children (mean ± SD age 13.6 ± 2.2 years, body mass index [BMI] z-score 3.04 ± 0.66, HOMA-IR 3.48 ± 2.28) anthropometrics, fat mass percentage (FM%), metabolic characteristics, physical activity, food intake and sleep were measured. Baseline characteristics did not differ between the groups. IR was higher in pubertal children with morbid obesity than in prepubertal children with morbid obesity (5.41 ± 1.86 vs 3.23 ± 1.86; P = .007) and prepubertal and pubertal children with overweight/obesity (vs 3.61 ± 1.60, P = .004, and vs 3.40 ± 1.50, P < .001, respectively). IR was associated with sex, Tanner stage, BMI z-score and FM%. Fasting glucose concentrations were negatively associated with Baecke sport score (r = -0.223, P = .025) and positively with daytime sleepiness (r = 0.280, P = .016) independent of sex, Tanner stage, BMI z-score and FM%. In conclusion, IR was most severe in pubertal children with morbid obesity. The associations between fasting glucose concentration and Baecke sport score and sleepiness suggest these might be possible targets for diabetes prevention.

The association between physical activity, fitness and body mass index on mental well-being and quality of life in adolescents.

PURPOSE: The purpose of the current study was to investigate the mediatory role between vigorous physical activity, body mass index (BMI), and cardiorespiratory fitness on symptoms of depression and their subsequent direct and indirect effects on quality of life (QoL). METHODS: Five hundred and seventy-six adolescents' (314 boys, 12.5 ± 1.1 years) physical activity levels, cardiorespiratory fitness, BMI, levels of depressive symptoms, and QoL were measured. Structural equation modelling was used to evaluate the difference in linear structural associations between variables. RESULTS: The model suggested that cardiorespiratory fitness (ß = 0.16, p < 0.001) and symptoms of depression (ß = - 0.52, p < 0.001) were both directly associated with physical QoL, with depressive symptoms also directly influencing psychological QoL (ß = - 0.79, p < 0.01). Body mass index was indirectly associated with physical QoL, mediated by both symptoms of depression (ß = - 0.06, p < 0.001) and cardiorespiratory fitness (ß = 0.05, p < 0.001) and psychological QoL mediated by symptoms of depression (ß = - 0.09, p < 0.001). Vigorous physical activity was indirectly associated with QoL, mediated by cardiorespiratory fitness (ß = - 0.04, p < 0.001). CONCLUSIONS: Models suggested that vigorous physical activity, cardiorespiratory fitness and BMI were associated, both directly and indirectly, with mental well-being and QoL. It could, therefore, be postulated that enhancing cardiorespiratory fitness and BMI through increasing vigorous physical activity may be beneficial to both mental well-being and QoL in adolescents.

Teenage recommendations to improve physical activity for their age group: a qualitative study.

BACKGROUND: It is recommended that young people should engage in 60 min of moderate-to-vigorous activity (MVPA) a day for health benefits, but few teenagers actually meet this recommendation. Policy-makers play a vital role in designing physical activity initiatives, but they generally do this with little or no input from the intervention recipients. This study explores the recommendations made by teenagers to improve activity provision, uptake and sustainability of physical activity engagement for both themselves and their peers. METHODS: Thirteen focus groups were carried out in seven secondary schools in South Wales, United Kingdom. Participants (n = 78) were recruited from a larger mixed-method randomised control trial, which involved the implementation of a voucher scheme to promote physical activity in teenagers (aged 13-14). Thematic analysis was undertaken to identify key issues from the perspective of the teenage participants. RESULTS: Six key recommendations were identified following analysis of the focus groups: i) Lower/remove the cost of activities without sacrificing the quality, ii) Make physical activity opportunities more locally accessible, iii) Improve the standards of existing facilities, iv) Make activities more specific to teenagers v) Give teenagers a choice of activities/increase variety of activity and vi) Provide activities that teenage girls enjoy (e.g., fun, sociable and not competitive sport). Throughout the focus groups, the increased opportunity to participate in unstructured activity was a key recommendation echoed by both boys and girls in all themes. CONCLUSION: There is a disconnect between what is available and what teenagers want to do. Policy-makers and those involved in physical activity delivery (e.g., schools, local council and local activity providers) should include young people in designing interventions and facilities to ensure they are meeting the needs of this age group and providing the right opportunities for teenagers to be active. That is unstructured, local, low cost, fun, sociable opportunities and the right facilities to be active.

Individual calibration of accelerometers in children and their health-related implications.

This study compared children's physical activity (PA) levels, the prevalence of children meeting current guidelines of ≥60 minutes of daily moderate to vigorous PA (MVPA), and PA-health associations using individually calibrated (IC) and empirical accelerometer cutpoints. Data from 75 (n = 32 boys) 10-12 year old children were included in this study. Clustered cardiometabolic (CM) risk, directly measured cardiorespiratory fitness (CRF), anthropometric and 7 day accelerometer data were included within analysis. PA data were classified using Froude anchored IC, Evenson et al. (Evenson, K. R., Catellier, D. J., Gill, K., Ondrak, K. S., & McMurray, R. G. (2008). Calibration of two objective measures of physical activity for children. Journal of Sports Sciences, 26(14), 1557-1565. doi:10.1080/02640410802334196) (Ev) and Mackintosh et al. (Mackintosh, K. A., Fairclough, S. J., Stratton, G., & Ridgers, N. D. (2012). A calibration protocol for population-specific accelerometer cutpoints in children. PLoS One, 7(5), e36919. doi:10.1371/journal.pone.0036919) (Mack) cutpoints. The proportion of the cohort meeting ≥60mins MVPA/day ranged from 37%-56% depending on the cutpoints used. Reported PA differed significantly across the cutpoint sets. IC LPA and MPA were predictors of CRF (LPA: standardised ß = 0.32, p = 0.002, MPA: standardised ß = 0.27 p = 0.013). IC MPA also predicted BMI Z-score (standardised ß = -0.35, p = 0.004). Ev VPA was a predictor of BMI Z-score (standardised ß = -0.33, p = 0.012). Cutpoint choice has a substantial impact on reported PA levels though no significant associations with CM risk were observed. Froude IC cutpoints represent a promising approach towards classifying children's PA data.