Objectively measured sedentary behaviour and health and development in children and adolescents: systematic review and meta-analysis.

Sedentary behaviour has emerged as a unique determinant of health in adults. Studies in children and adolescents have been less consistent. We reviewed the evidence to determine if the total volume and patterns (i.e. breaks and bouts) of objectively measured sedentary behaviour were associated with adverse health outcomes in young people, independent of moderate-intensity to vigorous-intensity physical activity. Four electronic databases (EMBASE MEDLINE, Ovid EMBASE, PubMed and Scopus) were searched (up to 12 November 2015) to retrieve studies among 2- to 18-year-olds, which used cross-sectional, longitudinal or experimental designs, and examined associations with health outcomes (adiposity, cardio-metabolic, fitness, respiratory, bone/musculoskeletal, psychosocial, cognition/academic achievement, gross motor development and other outcomes). Based on 88 eligible observational studies, level of evidence grading and quantitative meta-analyses indicated that there is limited available evidence that the total volume or patterns of sedentary behaviour are associated with health in children and adolescents when accounting for moderate-intensity to vigorous-intensity physical activity or focusing on studies with low risk of bias. Quality evidence from studies with robust designs and methods, objective measures of sitting, examining associations for various health outcomes, is needed to better understand if the overall volume or patterns of sedentary behaviour are independent determinants of health in children and adolescents.

Adiposity is related to decrements in cardiorespiratory fitness in obese and normal-weight children.

BACKGROUND: Obese children are typically less physically active than their normal-weight peers and are often assumed to be 'unfit'. OBJECTIVE: Investigate the relationships between adiposity, physical activity levels and cardiorespiratory fitness (CRF) in obese and normal-weight children. A secondary aim was to examine obese/normal-weight differences in CRF. METHODS: Obese (N = 107) and normal-weight (N = 132) 10-13-year-olds participated. Fat-free mass (FFM), percent fat, physical activity and peak oxygen uptake (VO2peak ) were assessed. Analyses were adjusted for socioeconomic status (SES). RESULTS: Higher percent fat was inversely associated with VO2peak normalized for mass (r = -0.780, P < 0.001) even after controlling for physical activity (r = -0.673, P < 0.001). While higher percent fat was also inversely associated with VO2peak normalized for FFM, this was only significant in males (r = -0.247, P = 0.004) and did not persist after controlling for physical activity (r = -0.059 P = 0.526). Compared with normal-weight children, obese children had higher absolute VO2peak , lower VO2peak corrected for mass (P ≤ 0.009) and lower VO2peak corrected for FFM (P = 0.041) that did not persist after controlling for SES (P = 0.086). CONCLUSION: Obesity-related inefficiencies in CRF were evident. Higher adiposity was associated with poorer CRF relative to mass, irrespective of physical activity levels. However, low physical activity levels may be responsible for associations between adiposity and CRF relative to FFM seen in boys, indicating the importance of encouraging physical activity.

Day-to-day physical functioning and disability in obese 10- to 13-year-olds.

UNLABELLED: What is already known about this subject? Compared with their healthy-weight peers, children with obesity have; impaired physical health-related quality of life reduced physical activity levels reduced capacity to perform certain weight-bearing tasks in field-based fitness tests What this study adds? First investigation of obesity-related disability in children using the International Classification for Functioning, Disability and Health framework for Children and Youth. Obesity in children appears to be associated with disability impacting basic locomotor skills and physical health-related quality of life. Children's participation in key life areas related to physical functioning appears to be minimally impacted by obesity. OBJECTIVE: The aim of this study was to investigate whether obesity is related to impaired day-to-day physical functioning and disability in children. METHODS: An observational case-control study was conducted in three Australian states. Obese (n = 107) and healthy-weight (n = 132) 10- to 13-year-olds (132 male, 107 female) were recruited via media advertisements. Assessment of body composition (dual energy X-ray absorptiometry), locomotor capacity (six-minute walk test [6MWT], timed up and down stairs test [TUDS] and timed up and go [TUG]) and child-reported physical health-related quality of life (HRQoL) were undertaken. Participants wore an accelerometer for 8 days and completed two use-of-time telephone interviews to assess participation in key life areas. RESULTS: Compared with their healthy-weight counterparts, obese children had lower physical HRQoL scores (P < 0.01) and reduced locomotor capacity (TUDS z-score, TUG and 6MWT; P < 0.01). Higher percent body fat was significantly related to lower physical HRQoL scores (r = -0.48, P < 0.01), slower performance times for the TUDS and TUG (r = 0.59 and 0.26 respectively, P < 0.01), shorter 6MWT distances (r = -0.51, P < 0.01) and reduced time spent in community participation activities (r = -0.23, P < 0.01). CONCLUSIONS: As anticipated, obesity appears to undermine physical functioning in children, including the capacity to perform basic locomotor skills yet, unexpectedly, participation in key life areas related to physical functioning appeared largely unaffected.

Obesity: the new childhood disability?

This review addresses the impact of obesity on paediatric physical functioning utilizing the World Health Organization International Classification of Functioning, Disability and Health Framework (ICF). The ICF encompasses functioning (as it relates to all body functions and structures), activities (undertaking a particular task) and participation (in a life situation) with disability referring to impairments in body functions/structures, activity restrictions or participation limitations. Electronic databases were searched for peer-reviewed studies published in English prior to May 2009 that examined aspects of physical functioning in children (≤18 years). Eligible studies (N = 104) were ranked by design and synthesized descriptively. Childhood obesity was found to be associated with deficits in function, including impaired cardiorespiratory fitness and performance of motor tasks; and there was some limited evidence of increased musculoskeletal pain and decrements in muscle strength, gait and balance. Health-related quality of life and the subset of physical functioning was inversely related to weight status. However, studies investigating impacts of obesity on wider activity and participation were lacking. Further research utilizing the ICF is required to identify and better characterize the effects of paediatric obesity on physical function, activity and participation, thereby improving targets for intervention to reduce disability in this population.

Health-related quality of life in obese children and adolescents.

OBJECTIVE: This review addresses the effect of overweight and obese weight status on pediatric health-related quality of life (HRQOL). METHOD: Web of Science, Medline, CINAHL, Cochrane Library, EMBASE, AMED and PubMed were searched for peer-reviewed studies in English reporting HRQOL and weight status in youth (<21 years), published before March 2008. RESULTS: Twenty-eight articles were identified. Regression of HRQOL against body mass index (BMI) using pooled data from 13 studies utilizing the Pediatric Quality of Life Inventory identified an inverse relationship between BMI and pediatric HRQOL (r=-0.7, P=0.008), with impairments in physical and social functioning consistently reported. HRQOL seemed to improve with weight loss, but randomized controlled trials were few and lacked long-term follow-up. CONCLUSIONS: Little is known about the factors associated with reduced HRQOL among overweight or obese youth, although gender, age and obesity-related co-morbidities may play a role. Few studies have examined the differences in HRQOL between community and treatment-seeking samples. Pooled regressions suggest pediatric self-reported HRQOL can be predicted from parent proxy reports, although parents of obese youths tend to perceive worse HRQOL than children do about themselves. Thus, future research should include both pediatric and parent proxy perspectives.