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Evidence-based obesity prevention in children
Invited Speakers resistance and vascular changes. Epigenetic mechanisms underpin much of this biology and these pathways coexist within populations in transition. A considerable portion of childhood adiposity can be explained by epigenetic variation at birth. Suggesting the importance of the prenatal environment to later obesogenic sensitivity. The mechanisms underpinning the effects of maternal obesity, on offspring obesity may also involve epigenetic processes. The rise in gestational diabetes is a further pathway of growing importance particularly in Asia. doi:10.1016/j.orcp.2010.09.169 Evidence-based obesity prevention in children John J. Reilly Royal Hospital for Sick Children and University of Glasgow, Scotland Prevention of childhood obesity has proved much more challenging than might have been expected, and the aetiology of childhood obesity is more complex than it might seem. In addition, in the UK there has been a marked gulf between the research evidence on aetiology and prevention and the policy action on prevention. The presentation will start by considering the knowledge of UK policymakers on targets for childhood obesity prevention, and the tendency of UK policy to be generally unresponsive to research evidence, yet sometimes overly sensitive to findings of individual studies. It will consider — briefly-the most well established behavioural targets for obesity prevention interventions, recent systematic reviews, and the most promising school and community based interventions aimed at childhood obesity prevention. Finally, the presentation will consider some emerging evidence, and the challenges this evidence might present for childhood obesity prevention in future: the size of the energy imbalance experienced by contemporary children and adolescents and the consequences this has for the magnitude of lifestyle changes required to prevent obesity; heterogeneity in the aetiology of obesity; heterogeneity in the prevention of obesity (such as differences between groups defined by age, socio-economic status, initial weight status, or ethnicity); the ‘natural history’ of excess weight gain as well as obesity in contemporary children and adolescents, using an example from the ALSPAC cohort study in England; the importance of evidence on incidence and persistence of obesity, in addition to the more commonly studied prevalence, using an example from the ALSPAC cohort. doi:10.1016/j.orcp.2010.09.170
S87 How do we measure sedentary behaviours in young people? John J. Reilly Royal Hospital for Sick Children and University of Glasgow, Scotland Sedentary behaviour is now well established as being important to current and future health of children and adolescents, particularly in the aetiology, prevention, and treatment of child and adolescent obesity. Sedentary behaviour can no longer be seen as simply a lack of physical activity. One major challenge in measurement is the emerging complexity of the construct, and it is unlikely that any single measurement method will capture all the aspects of sedentary behaviour which are likely to be of interest. Sedentary behaviours may be defined as lack of trunk movement, or as activities with low energy expenditure, and measured using ‘traditional’ accelerometry calibrated against direct observation and/or energy expenditure. Alternatively, accelerometers with inclinometers might provide more accurate measurement of sedentary behaviour, and can provide information on posture (e.g. sitting vs. standing time) and posture transitions (e.g. bouts of sitting time, breaks in sitting) which may also be valuable. Other aspects of sedentary behaviour may be important, such as fidgeting, and these may be measured adequately using existing technology. Screen time is arguably the most important dimension of sedentary behaviour for child health and development, but quantitative measurement is challenging. Further research will be required in order to identify the most important aspects of sedentary behaviour to measure, and the choice of which aspect to measure should depend on the particular application. Quantitative measurement of sedentary behaviour requires objective measurement, but some aspects of sedentary behaviour are more amenable to objective measurement than others. At the very least, researchers should be clear about which aspects of sedentary behaviour they are measuring and why, should describe the measurement methods used clearly, should use methods validated and calibrated in the paediatric age range, and should use unambiguous terminology to describe the constructs they measure. doi:10.1016/j.orcp.2010.09.171
S87 How do we measure sedentary behaviours in young people? John J. Reilly Royal Hospital for Sick Children and University of Glasgow, Scotland Sedentary behaviour is now well established as being important to current and future health of children and adolescents, particularly in the aetiology, prevention, and treatment of child and adolescent obesity. Sedentary behaviour can no longer be seen as simply a lack of physical activity. One major challenge in measurement is the emerging complexity of the construct, and it is unlikely that any single measurement method will capture all the aspects of sedentary behaviour which are likely to be of interest. Sedentary behaviours may be defined as lack of trunk movement, or as activities with low energy expenditure, and measured using ‘traditional’ accelerometry calibrated against direct observation and/or energy expenditure. Alternatively, accelerometers with inclinometers might provide more accurate measurement of sedentary behaviour, and can provide information on posture (e.g. sitting vs. standing time) and posture transitions (e.g. bouts of sitting time, breaks in sitting) which may also be valuable. Other aspects of sedentary behaviour may be important, such as fidgeting, and these may be measured adequately using existing technology. Screen time is arguably the most important dimension of sedentary behaviour for child health and development, but quantitative measurement is challenging. Further research will be required in order to identify the most important aspects of sedentary behaviour to measure, and the choice of which aspect to measure should depend on the particular application. Quantitative measurement of sedentary behaviour requires objective measurement, but some aspects of sedentary behaviour are more amenable to objective measurement than others. At the very least, researchers should be clear about which aspects of sedentary behaviour they are measuring and why, should describe the measurement methods used clearly, should use methods validated and calibrated in the paediatric age range, and should use unambiguous terminology to describe the constructs they measure. doi:10.1016/j.orcp.2010.09.171