School gate to dinner plate : sedentary and physically active behaviours in adolescents after school

Against a backdrop of rising overweight and obesity, there is a need to further our understanding of physical activity and sedentary behaviour patterns in young people to aid the development of behaviour change strategies that may bring about an increase in energy expenditure. Sedentary and active behaviours exhibit temporal patterning, thus it may be beneficial to examine behaviour and associations between behaviours during specific periods of the day This thesis presents five studies that examine sedentary and physically active behaviours in adolescents during the three hours immediately after school. Chapter 2, using data from a large study of adolescents in the UK, describes physical activity and sedentary behaviour patterns between 15.30h - 18.30h, and examines the contribution of this period relative to broader leisure-time behaviour patterns. In chapter 3.1, the' associations between a broad range of sedentary behaviours and objectively assessed physical activity are examined during the after school hours, providing unique insight into the interactions between behaviours at this time. Chapter 3.2 explores the social and environmental context of selected sedentary and active behaviours after school, enabling a more complete understanding of where and with whom young people spend their time during these hours. Chapter 4 is a systematic literature review of interventions to increase physical activity in young people conducted in the hours immediately after school. Together, the four studies described above established a rationale and informed the content of a pilot family-based intervention to reduce screen-time and increase physical activity after school, presented in Chapter 5. Approximately 40% of adolescents' leisure-time physical activity occurs in the three hours immediately after school, suggesting that this is a critical period in which young people obtain a significant proportion of their daily leisure-time activity. However, sedentary behaviours, particularly screen-based media, account for the majority of time-use during these hours, and may displace participation in physical activity. The development of time-targeted intervention strategies, with a focus upon the after school period, holds considerable promise for the promotion of physical activity in young people

Effects of human recombinant growth hormone on exercise capacity, cardiac structure, and cardiac function in patients with adult-onset growth hormone deficiency

Objective Epidemiological studies suggest that adult-onset growth hormone deficiency (AGHD) might increase the risk of death from cardiovascular causes. Methods This was a 6-month double-blind, placebo-controlled, randomised, cross-over trial followed by a 6-month open-label phase. Seventeen patients with AGHD received either recombinant human growth hormone (rGH) (0.4 mg injection daily) or placebo for 12 weeks, underwent washout for 2 weeks, and were then crossed over to the alternative treatment for a further 12 weeks. Cardiac magnetic resonance imaging, echocardiography, and cardiopulmonary exercise testing were performed at baseline, 12 weeks, 26 weeks, and the end of the open phase (12 months). The results were compared with those of 16 age- and sex-matched control subjects. Results At baseline, patients with AGHD had a significantly higher systolic blood pressure, ejection fraction, and left ventricular mass than the control group, even when corrected for body surface area. Treatment with rGH normalised the insulin-like growth factor 1 concentration without an effect on exercise capacity, cardiac structure, or cardiac function. Conclusion Administration of rGH therapy for 6 to 9 months failed to normalise the functional and structural cardiac differences observed in patients with AGHD when compared with a control group

The Quest for the Magnetic Pole: navigation and research into polar terrestrial magnetism

At the conclusion of Scott’s Discovery expedition, Albert Armitage wrote the following: The observations for variation have proved very good, and the results of these alone are sufficient reward for all the monotonous labour connected with the magnetic observations, if, as I believe they will do, they enable those who go down to the sea in ships to navigate with a greater measure of confidence and safety those waters that wash the shores of our southern possessions and South America. (Armitage 1905) Armitage was one of many navigators, scientists and expeditioners to investigate the nature of terrestrial magnetism up to the famous sledge journey by Mawson, McKay and David to the vicinity of the south magnetic pole in January 1909. I believe that geomagnetic research flourished between 1830 and the Heroic era of Antarctic exploration. Although much research had been undertaken during that period, and many questions answered, Louis Bauer (Director of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington) indicated there were still gaps in fundamental knowledge when he wrote in 1914: The accumulation of data must at present be the chief aim of the student of the earth’s magnetism.(Bauer 1914) This review will briefly describe some aspects of development of the science of geomagnetic research, especially during the Victorian era. It will also discuss its place in the art of traditional navigation and the linkage to selected high latitude expeditions

Sporopollenin, the least known yet toughest natural biopolymer

© 2015 Mackenzie, Boa, Diego-Taboada, Atkin and Sathyapalan. Sporopollenin is highly cross-linked polymer composed of carbon, hydrogen, and oxygen that is extraordinarily stable and has been found chemically intact in sedimentary rocks some 500 million years old. It makes up the outer shell (exine) of plant spores and pollen and when extracted it is in the form of an empty exine or microcapsule. The exines resemble the spores and pollen from which they are extracted, in size and morphology. Also, from any one plant such characteristics are incredible uniform. The exines can be used as microcapsules or simply as micron-sized particles due to the variety of functional groups on their surfaces. The loading of a material into the chamber of the exine microcapsule is via multi-directional nano-diameter sized channels. The exines can be filled with a variety of polar and non-polar materials. Enzymes can be encapsulated within the shells and still remain active. In vivo studies in humans have shown that an encapsulated active substance can have a substantially increased bioavailability than if it is taken alone. The sporopollenin exine surface possesses phenolic, alkane, alkene, ketone, lactone, and carboxylic acid groups. Therefore, it can be derivatized in a number of ways, which has given rise to applications in areas, such as solid supported for peptide synthesis, catalysis, and ion-exchange chromatography. Also, the presence of the phenolic groups on sporopollenin endows it with antioxidant activity

Socioeconomic and ethnic differences in children's vigorous intensity physical activity: a cross-sectional analysis of the UK Millennium Cohort Study.

OBJECTIVE: To investigate if daily vigorous physical activity (VPA), adjusted for minutes of moderate physical activity (MPA) performed, differs by socioeconomic position or ethnicity in a large sample of UK children with objectively measured physical activity. DESIGN: Nationally representative prospective cohort study. SETTING: UK children born between 2000 and 2002. PARTICIPANTS: 5172 children aged 7-8 with valid accelerometer data for ≥10 hour on ≥3 days, including 1 weekend day. MAIN OUTCOME MEASURES: Time spent in VPA (>3841 counts per min). EXPLANATORY MEASURES: Maternal education, annual household Organisation for Economic Co-Operation and Development equivalised income, ethnicity. RESULTS: Multivariable linear regression models fitted to explore differences in average daily minutes of VPA (adjusted for MPA, mean accelerometer wear time, season of measurement, age and sex), revealed significantly higher amounts of VPA accumulated as a child's socioeconomic position increased (highest vs lowest level of maternal education: β: 2.96, p: 0.00; annual household equivalised income: β: 0.58, p: 0.00, per £10 000 annual increase). Additionally, children from certain minority ethnicities (Bangladeshi and Pakistani: β: -3.34, p: 0.00; other ethnic groups: β:-2.27, p: 0.02) accrued less daily VPA compared with their white British counterparts. CONCLUSIONS: The socioeconomic and ethnic patterning of vigorous activity observed in this study mirrors parallel inequalities in rates of childhood obesity. Given the stronger association of VPA with adiposity than of MPA, intensity specific differences may be contributing to widening inequalities in obesity. Accordingly, these findings suggest that the current global focus on overall moderate-to-vigorous intensity activity may mask important behavioural inequalities.Funding for this study and the work of all authors was supported, wholly or in part, by the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research Centre of Excellence (087636/Z/08/Z; ES/G007462/1; MR/K023187/1). Funding from the British Heart Foundation, Department of Health, Economic and Social Research Council, Medical Research Council, and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged. Rebecca Love is funded by a Gates Cambridge Scholarship. The work of Esther M F van Sluijs was supported by the Medical Research Council (MC_UU_12015/7). No funders were involved in the production of this manuscript

Bedroom media, sedentary time and screen-time in children:A longitudinal analysis

Background: Having electronic media in the bedroom is cross-sectionally associated with greater screen-time in children, but few longitudinal studies exist. The aim of this study was to describe longitudinal patterns of ownership and examine cross-sectional and longitudinal associations of bedroom media with children's sedentary behaviour. Methods: Data are from the Sport, Physical activity and Eating behaviour: Environmental Determinants in Young people (SPEEDY) study, collected at 3 time-points: baseline (2007, T0; age 10.3 ± 0.3 years), 1-year (T1y) and 4-year (T4y) follow-up. For each assessment, 1512 (44.9% male), 715 (41.0% male), and 319 (48.3% male) participants provided valid accelerometer data. Outcome variables were accelerometer-assessed sedentary time and self-reported screen-time. The presence of a television or computer in the bedroom was self-reported by participants and a combined bedroom media score calculated as the sum of such items. Cross-sectional and longitudinal associations between bedroom media and each outcome were examined using multi-level linear regression. Results: Bedroom TV ownership fell from 70.9% at T0 to 42.5% at T4y. Having a TV in the bedroom (beta; 95% CI*100, T0: -1.17; -1.88, -0.46. T1y: -1.68; -2.67, -0.70) and combined bedroom media (T0: -0.76; -1.26, -0.27. T1y: -0.79; -1.51, -0.07) were negatively associated with objectively measured weekly sedentary time at T0 and T1y. Having a computer in the bedroom (beta; 95% CI, T0: 0.15; 0.02, 0.29. T4y: 0.35; 0.10, 0.60) and combined bedroom media (T0: 0.09: 0.01, 0.18. T4y: 0.20; 0.05, 0.34) were positively associated with screen-time at T0 and T4y. Relative to participants without a computer throughout the study, children that had a computer in their bedroom at T0 but not at T4y (beta; 95% CI for change in screen-time: -8.02; -12.75, -3.29) reported smaller increases in screen-time. Conclusions: The bedroom media environment changes with age and exhibits a complex relationship with children's sedentary behaviour. Modifying children's bedroom media environment may impact upon screen-time but appears unlikely to influence overall sedentary time

Family circumstance, sedentary behaviour and physical activity in adolescents living in England: Project STIL

<p>Abstract</p> <p>Background</p> <p>Identification of non-modifiable correlates of physical activity and sedentary behaviour in youth contributes to the development of effective targeted intervention strategies. The purpose of this research was to examine the relationships between family circumstances (e.g. socio-economic status, single vs. dual parent household, presence/absence of siblings) and leisure-time physical activity and sedentary behaviours in adolescents.</p> <p>Methods</p> <p>A total of 1171 adolescents (40% male; mean age 14.8 years) completed ecological momentary assessment diaries every 15 minutes for 3 weekdays outside of school hours and 1 weekend day. Analysed behaviours were sports/exercise, active travel, TV viewing, computer use, sedentary socialising (hanging-out, using the telephone, sitting and talking) and total sedentary behaviour. Linear regression was employed to estimate levels of association between individual family circumstance variables and each behaviour.</p> <p>Results</p> <p>Compared to girls from higher socioeconomic status (SES) groups, girls from low SES groups reported higher weekend TV viewing and higher weekday total sedentary behaviour. For boys, single parent status was associated with greater total sedentary behaviour compared to those from dual parent households. Boys and girls from low socio-economic neighbourhoods reported lower participation in sports/exercise compared to those living in higher socio-economic neighbourhoods.</p> <p>Conclusion</p> <p>Associations were not consistent across behaviours or between genders. Overall, findings indicate that boys from single parent households and girls from low socio-economic families may be at increased risk of high sedentary behaviour. Those living in low socioeconomic neighbourhoods may be at increased risk of reduced participation in sports and exercise.</p

Clustering and correlates of multiple health behaviours in 9-10 year old children.

BACKGROUND: Sleep, physical activity, screen time and dietary behaviours influence health during childhood, but few studies have looked at all of these behaviours simultaneously and previous research has relied predominantly on self- or proxy-reports of physical activity and food frequency questionnaires for the assessment of diet. PURPOSE: To assess the prevalence and clustering of health behaviours and examine the socio-demographic characteristics of children that fail to meet multiple health behaviour guidelines. METHODS: Data are from the Sport, Physical activity and Eating behaviour: Environmental Determinants in Young people (SPEEDY) study. Participants (n = 1472, 42.9% male) were dichotomized based on whether or not they met public health guidelines for accelerometer-assessed physical activity, diet-diary assessed fruit/vegetable intake and fat/non-milk extrinsic sugar (NMES) intake, and self-reported screen time and sleep duration. Behavioural clustering was assessed using an observed over expected ratio (O/E). Socio-demographic characteristics of participants that failed to meet multiple health behaviour guidelines were examined using ordinal logistic regression. Data were analysed in 2013. RESULTS: 83.3% of children failed to meet guidelines for two or more health behaviours. The O/E ratio for two behavioural combinations significantly exceeded 1, both of which featured high screen time, insufficient fruit/vegetable consumption and excessive fat/NMES intake. Children who were older (Proportional odds ratio (95% confidence interval): 1.69 (1.21,2.37)) and those that attended a school with a physical activity or diet-related policy (1.28 (1.01,1.62)) were more likely to have a poor health behaviour profile. Girls (0.80 (0.64,0.99)), participants with siblings (0.76 (0.61,0.94)) and those with more highly educated parents (0.73 (0.56,0.94)) were less likely to have a poor health behaviour profile. CONCLUSIONS: A substantial proportion of children failed to meet guidelines for multiple health behaviours and there was evidence of clustering of screen viewing and unhealthy dietary behaviours. Sub-groups at greatest risk may be targeted for intervention.This is the final published version, which can also be found online at: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0099498#ac

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