Sedentary behaviors and adiposity in young people: causality and conceptual model

Research on sedentary behavior and adiposity in youth dates back to the 1980s. Sedentary behaviors, usually screen time, can be associated with adiposity. Although the association usually is small but significant, the field is complex, and results are dependent on what sedentary behaviors are assessed and may be mediated and moderated by other behaviors

Interventions designed to reduce sedentary behaviours in young people: A review of reviews

Background: Leisure time is increasingly spent in sedentary pursuits such as screen-viewing (eg, television/DVD viewing and computer use), motorised travel, school/work and sitting-based socialising (eg, social media and chatting). Sedentary screen time, particularly TV, appears to play an important role in the aetiology of obesity due to its co-occurrence with other unhealthy behaviours such as snacking on energy-dense foods, low levels of physical activity and inadequate sleep. More information is needed on how to reduce sedentary behaviours. Most interventions have focused on young people and a number of systematic reviews exist on this topic. Objective: To synthesise systematic reviews and metaanalyses of interventions aimed at decreasing sedentary behaviours among children and adolescents. Methods: Papers were located from computerised and manual searches. Included articles were English language systematic reviews or meta-analyses of interventions aiming at reducing sedentary behaviour in children (<11 years) and adolescents (12-18 years). Results: Ten papers met the inclusion criteria and were analysed. All reviews concluded some level of effectiveness in reducing time spent in sedentary behaviour. When an effect size was reported, there was a small but significant reduction in sedentary time (highest effect size=-0.29; CI -0.35 to -0.22). Moderator analyses showed a trend favouring interventions with children younger than 6 years. Effective strategies include the involvement of family, behavioural interventions and electronic TV monitoring devices. Conclusions: Results from systematic reviews and meta-analyses show that interventions to reduce children's sedentary behaviour have a small but significant effect. Future research should expand these findings examining interventions targeting different types of sedentary behaviours and the effectiveness of specific behaviour change techniques across different contexts and settings

The effectiveness of interventions to increase physical activity among young girls: a meta-analysis

Context: Pre-adolescent girls are an important target population for physical activity behaviour change as it may enhance tracking into the crucial period of adolescence. The quantification of intervention effectiveness for this age group of girls has not been previously reported. Evidence acquisition: Studies published in English up to and including August 2013 were located from computerised (MedLine, PsychInfo, Science Direct, Web of Science, EPPI centre databases, and Cochrane Library database) and manual searches. Intervention studies aimed at promoting physical activity, which included pre-adolescent girls aged 5-11. years, and a non-physical activity control/comparison group were included. Evidence synthesis: A random effects meta-analysis was conducted. The average treatment effect for pre-adolescent girls involved in physical activity interventions was significant but small (g = 0.314, p < .001). Moderator analyses showed larger effects for interventions that catered for girls only and used educational and multicomponent strategies. Conclusions: Interventions to increase physical activity in pre-adolescent girls show small but significant effects, suggesting that behaviour change may be challenging, but results suggest some strategies that could be successful. © 2014 Elsevier Inc

Glyphosate in waters and soils from genetically modified canola cultivation in Parkes, NSW, Australia

Investigations were conducted of farmland from the Parkes region of New South Wales, Australia, cultivated with genetically modified canola, involving the determination of glyphosate (N-(phosphonomethyl)glycine) concentrations in water and soils, and its sorption. The soils are classified as loam under the USDA system (clay 13.8-15.8%, silt 39-43%, sand 41.2-47.2%). Firstly, a low-cost fluorometric method was developed for the analysis of glyphosate in waters and soils, calibrated against analytical standards and spectrophotometric and enzyme-linked immunosorbent assay (ELISA) methods. Soil and water samples were then collected using the NEPM sampling protocol into glass containers, chilled and analysed within two weeks. The samples were collected in multiple episodes, taking account of glyphosate and pesticide crop applications. The soil and water physical and chemical properties were characterised, and glyphosate levels were determined. Field concentrations of glyphosate ranged between 0.01 - 0.067 mg/L in water and 0.10 - 0.575 mg/kg in soil. The aqueous levels lie below Australian and international drinking water guidelines, but reach a Canadian freshwater guideline. Glyphosate levels varied with time of application and rainfall events. Glyphosate sorption isotherms were also constructed by batch tests on several soils, and were fitted with Freundlich and Langmuir isotherms. Desorption tests indicated 25% to 58% of soil glyphosate is extractable by 0.1M KH2PO4

The effectiveness of interventions to increase physical activity among adolescent girls: A meta-analysis

Background Research has shown that a clear decline in physical activity among girls starting in early adolescence. Therefore, adolescent girls have been identified as a key target population for physical activity behavior change. The quantification of intervention effectiveness for this group has not been previously reported in a meta-analysis, and this therefore was the objective of the current meta-analysis. Study Selection Included were interventions in which the main component, or 1 of the components, was aimed at promoting physical activity through behavior change in any setting. Interventions had to include a non–physical activity control group or comparison group, and include a quantitative outcome assessment of physical activity behavior in girls aged 12 to 18 years. Data Sources Science Direct, PubMed, PsychINFO, Web of Science, Cochrane Libraries, and EPPI Centre databases were searched up to and including May 2013. Data Extraction and Synthesis Forty-five studies (k = 34 independent samples) were eligible from an initial 13,747 references. A random-effects meta-analysis was conducted. Results The average treatment effect for adolescent girls involved in physical activity interventions was significant but small (g = 0.350, 95% confidence interval 0.12, 0.58, P < .001). Moderator analyses showed larger effects for interventions that were theory based, performed in schools, were girls only, with younger girls, used multicomponent strategies, and involved targeting both physical activity and sedentary behavior. Conclusions Interventions to increase physical activity in adolescent girls show small but significant effects, suggesting that behavior change may be challenging. Results suggest some approaches that appear to be successful

An assessment of self-reported physical activity instruments in young people for population surveillance: Project ALPHA

<p>Abstract</p> <p>Background</p> <p>The assessment of physical activity is an essential part of understanding patterns and influences of behaviour, designing interventions, and undertaking population surveillance and monitoring, but it is particularly problematic when using self-report instruments with young people. This study reviewed available self-report physical activity instruments developed for use with children and adolescents to assess their suitability and feasibility for use in population surveillance systems, particularly in Europe.</p> <p>Methods</p> <p>Systematic searches and review, supplemented by expert panel assessment.</p> <p>Results</p> <p>Papers (n = 437) were assessed as potentially relevant; 89 physical activity measures were identified with 20 activity-based measures receiving detailed assessment. Three received support from the majority of the expert group: Physical Activity Questionnaire for Children/Adolescents (PAQ-C/PAQ-A), Youth Risk Behaviour Surveillance Survey (YRBS), and the Teen Health Survey.</p> <p>Conclusions</p> <p>Population surveillance of youth physical activity is strongly recommended and those involved in developing and undertaking this task should consider the three identified shortlisted instruments and evaluate their appropriateness for application within their national context. Further development and testing of measures suitable for population surveillance with young people is required.</p

Family influences on children's physical activity and fruit and vegetable consumption

Background : There is evidence of a clustering of healthy dietary patterns and physical activity among young people and also of unhealthy behaviours. The identification of influences on children\u27s health behaviors, particularly clustered health behaviors, at the time at which they develop is imperative for the design of interventions. This study examines associations between parental modelling and support and children\u27s physical activity (PA) and consumption of fruit and vegetables (FV), and combinations of these behaviours.Methods : In 2002/3 parents of 775 Australian children aged 10&ndash;12 years reported how frequently their child ate a variety of fruits and vegetables in the last week. Children wore accelerometers for eight days during waking hours. Parental modelling and parental support (financial and transport) were self-reported. Binary logistic and multinomial logistic regression analyses examined the likelihood of achieving &ge; 2 hours of PA per day (high PA) and of consuming &ge; 5 portions of FV per day (high FV) and combinations of these behaviors (e.g. high PA/low FV), according to parental modelling and support.Results : Items of parental modelling and support were differentially associated with child behaviours. For example, girls whose parents reported high PA modelling had higher odds of consuming &ge; 5 portions of FV/day (OR = 1.95, 95% CI = 1.32&ndash;2.87, p &lt; 0.001). Boys whose parents reported high financial support for snacks/fast foods had higher odds of having \u27high PA/low FV\u27 (OR = 2.0, 95% CI = 1.1&ndash;3.7).Conclusion : Parental modelling of and support for physical activity and fruit and vegetable consumption were differentially associated with these behaviours in children across behavioural domains and with combinations of these behaviours. Promoting parents\u27 own healthy eating and physical activity behaviours as well encouraging parental modelling and support of these behaviours in their children may be important strategies to test in future research.<br /

Adolescent television viewing and unhealthy snack food consumption: the mediating role of home availability of unhealthy snack foods

Objective To examine whether home availability of energy-dense snack foods mediates the association between television (TV) viewing and energy-dense snack consumption among adolescents.Design Cross-sectional.Setting Secondary schools in Victoria, Australia.Subjects Adolescents (n 2984) from Years 7 and 9 of secondary school completed a web-based survey, between September 2004 and July 2005, assessing their energy-dense snack food consumption, school-day and weekend-day TV viewing and home availability of energy-dense snack foods.Results School-day and weekend-day TV viewing were positively associated with energy-dense snack consumption among adolescent boys (&beta; = 0&middot;003, P &lt; 0&middot;001) and girls (&beta; = 0&middot;03, P &lt; 0&middot;001). Furthermore, TV viewing (school day and weekend day) were positively associated with home availability of energy-dense snack foods among adolescent boys and girls and home availability of energy-dense snack foods was positively associated with energy-dense snack food consumption among boys (&beta; = 0&middot;26, P &lt; 0&middot;001) and girls (&beta; = 0&middot;28, P &lt; 0&middot;001). Home availability partly mediated the association between TV viewing and energy-dense snack consumption.Conclusions The results of the present study suggest that TV viewing has a significant role to play in adolescent unhealthy eating behaviours. Future research should assess the efficacy of methods to reduce adolescent energy-dense snack food consumption by targeting parents to reduce home availability of energy-dense foods and by reducing TV viewing behaviours of adolescents

Patterns of adolescent physical activity and dietary behaviours

<p>Abstract</p> <p>Background</p> <p>The potential synergistic effects of multiple dietary and physical activity behaviours on the risk of chronic conditions and health outcomes is a key issue for public health. This study examined the prevalence and clustering patterns of multiple health behaviours among a sample of adolescents in the UK.</p> <p>Methods</p> <p>Cross-sectional survey of 176 adolescents aged 12–16 years (49% boys). Adolescents wore accelerometers for seven days and completed a questionnaire assessing fruit, vegetable, and breakfast consumption. The prevalence of adolescents meeting the physical activity (≥ 60 minutes moderate-to-vigorous physical activity/day), fruit and vegetable (≥ 5 portions of FV per day) and breakfast recommendations (eating breakfast on ≥ 5 days per week), and clustering patterns of these health behaviours are described.</p> <p>Results</p> <p>Boys were more active than girls (p < 0.001) and younger adolescents were more active than older adolescents (p < 0.01). Boys ate breakfast on more days per week than girls (p < 0.01) and older adolescents ate more fruit and vegetables than younger adolescents (p < 0.01). Almost 54% of adolescents had multiple risk behaviours and only 6% achieved all three of the recommendations. Girls had significantly more risk factors than boys (p < 0.01). For adolescents with two risk behaviours, the most prevalent cluster was formed by not meeting the physical activity and fruit and vegetable recommendations.</p> <p>Conclusion</p> <p>Many adolescents fail to meet multiple diet and physical activity recommendations, highlighting that physical activity and dietary behaviours do not occur in isolation. Future research should investigate how best to achieve multiple health behaviour change in adolescent boys and girls.</p