Daniel Aggio

Temporal relationships between screen-time and physical activity with cardiorespiratory fitness in English schoolchildren: a 2-year longitudinal study.

OBJECTIVE To determine the temporal relationships screen-time and physical activity have with cardiorespiratory fitness. METHOD Measures were made over two years (2008-2010) in 1500 participants aged 11.5 (SD 0.5) years at baseline. RESULTS Tracking coefficients were low-to-moderate for all measures. At follow-up, 25% of participants moved from having low (<2h) to high (≥ 2 h) daily screen-time and 6% became unfit according to FITNESSGRAM standards. Baseline screen-time was the strongest univariate predictor of becoming unfit. Multivariate analysis controlling for decimal age, BMI and deprivation confirmed baseline screen-time as the strongest independent predictor of becoming unfit over the 2-year study period (OR 2.4; 95%CI:1.4-4.0). Current (OR 2.3; 95%CI:1.3-4.0) and previous (OR 1.7; 95%CI:1.0-2.9) physical activity levels also independently predicted becoming unfit. CONCLUSION There is currently no guidance for limiting screen-time in UK children. These longitudinal data add to the cross-sectional evidence of lower physical activity and fitness in children reporting ≥ 2 h daily screen-time. More importantly, these data demonstrate that high screen-time during childhood is an independent predictor of lower cardiorespiratory fitness in adolescence.

Association between participation in outdoor play and sport at 10 years old with physical activity in adulthood.

OBJECTIVE This study aimed to investigate whether active outdoor play and/or sports at age 10 is associated with sport/physical activity at 32 year follow-up using a birth cohort study. METHODS Data were from the 1970 British Cohort Study, a longitudinal observational study. The present paper included data from the age 10 years and age 42 years surveys. At age 10 the participants mother provided information regarding how often their child played sports, and played outside on streets, parks or playgrounds. At age 42 participants reported frequency of participation in physical activities and sports. Associations between participation in sport/active outdoor play at age 10 years and adult sport/physical activity were investigated using adjusted (gender, fathers socio-occupational class, childs BMI, fathers BMI, self-rated health at age 42, assessment of own weight at age 42, participants education) Cox regression. RESULTS Final adjusted Cox regression models showed that participants (n=6458) who often participated in sports at age 10 were significantly more likely to participate in sport/physical activity at age 42 (RR 1.10; 95% CI 1.01 to 1.19). Active outdoor play at age 10 was not associated with participation in sport/physical activity at age 42 (RR 0.99; 95% CI 0.91 to 1.07). CONCLUSION Childhood activity interventions might best achieve lasting change by promoting engagement in sport rather than active outdoor play.

Context-Specific Associations of Physical Activity and Sedentary Behavior With Cognition in Children

In the present study, we investigated how overall and specific domains of physical activity and sedentary behavior at the age of 7 years were associated with cognition at the age of 11 years in 8,462 children from the Millennium Cohort Study. Data were collected from 2001 to 2013. Participation in domains of physical activity and sedentary behavior at 7 years of age were reported. Activity levels were also measured objectively. Cognition was assessed using the British Ability Scales. General linear models were used to assess longitudinal associations of physical activity and sedentary behavior, measured both objectively and via self-report, with cognition. Analyses were adjusted for prespecified covariates. Sports/physical activity club attendance (B = 0.6, 95% confidence interval (CI): 0.2, 1.1), doing homework (B = 0.5, 95% CI: 0.0, 0.9), and objectively measured sedentary time (B = 0.8, 95% CI: 0.1, 1.4) at age 7 years were positively associated with cognition at age 11 years in final the models. Television viewing was negatively associated with cognition (B = −1.7, 95% CI: −2.4, −1.0), although the association was attenuated to the null after adjustments for baseline cognition. Objectively measured light physical activity was inversely associated with cognition (B = −0.7, 95% CI: −1.3, −0.1). Moderate-to-vigorous physical activity was also inversely associated with cognition in girls only (B = −1.1, 95% CI: −2.0, −0.3). Associations of physical activity and sedentary behavior with cognition appear to be context-specific in young people.

Cross-sectional associations of objectively measured physical activity and sedentary time with sarcopenia and sarcopenic obesity in older men

This study investigated associations between objectively measured physical activity (PA) with sarcopenia and sarcopenic obesity in older British men. Participants were men aged 70–92 years (n = 1286) recruited from UK Primary Care Centres. Outcomes included (i) sarcopenia, defined as low muscle mass (lowest two fifths of the mid-upper arm muscle circumference distribution) accompanied by low muscular strength (hand grip strength < 30 kg) or low physical performance (gait speed ≤ 0.8 m/s); (ii) severe sarcopenia, required all three conditions; (iii) sarcopenic obesity defined as sarcopenia or severe sarcopenia and a waist circumference of > 102 cm. Independent variables included time spent in PA intensities measured by GT3x accelerometers, worn during one week in 2010–12. Multinomial regression models were used for cross-sectional analyses relating PA and sarcopenia. In total, 14.2% (n = 183) of men had sarcopenia and a further 5.4% (n = 70) had severe sarcopenia. 25.3% of sarcopenic or severely sarcopenic men were obese. Each extra 30 min per day of moderate-to-vigorous PA (MVPA) was associated with a reduced risk of severe sarcopenia (relative risk [RR] 0.53, 95% confidence interval [CI] 0.30, 0.93) and sarcopenic obesity (RR 0.47 [95% CI 0.27, 0.84]). Light PA (LPA) and sedentary breaks were marginally associated with a reduced risk of sarcopenic obesity. Sedentary time was marginally associated with an increased risk of sarcopenic obesity independent of MVPA (RR 1.18 [95% CI 0.99, 1.40]). MVPA may reduce the risk of severe sarcopenia and sarcopenic obesity among older men. Reducing sedentary time and increasing LPA and sedentary breaks may also protect against sarcopenic obesity.

Camden active spaces: Does the construction of active school playgrounds influence children's physical activity levels? A longitudinal quasi-experiment protocol

Introduction Physical activity is essential for every facet of childrens health. However, physical activity levels in British children are low. The school environment is a promising setting to increase childrens physical activity but limited empirical evidence exists on how a change in the outdoor physical school environment influences physical activity behaviour. The London Borough of Camden is redesigning seven existing school playgrounds to engage children to become more physically active. The primary aim of this project is to evaluate the impact of the redesigned playgrounds on childrens physical activity, well-being and physical function/fitness. Method and analysis This project will use a longitudinal quasi-experimental design. Seven experimental schools and one control school will take part. One baseline data collection session and two follow-ups will be carried out. Between baseline and follow-up, the experimental school playgrounds will be redesigned. At baseline, a series of fitness tests, anthropometric and questionnaire measurements, and 7-day objective physical activity monitoring (Actigraph accelerometer) will be carried out on children (aged 5–16 years). This will be repeated at follow-up. Changes in overall physical activity levels and levels during different times of the day (eg, school breaks) will be examined. Multilevel regression modelling will be used to analyse the data. Ethics and dissemination The results of this study will be disseminated through peer-review publications and scientific presentations. Ethical approval was obtained through the University College London Research Ethics Committee (Reference number: 4400/002).

Sedentary behaviour among elite professional footballers: health and performance implications

Background Elite athletes should have little concern about meeting recommended guidelines on physical activity. However, sedentary behaviour is considered a health risk independent of physical activity, and is recognised in public health guidelines advising against prolonged sedentary time. There has been very little research on athletes’ physical activity behaviour outside elite sport. Methods Given health and performance links, we investigated in-season post-training activity levels in 28 elite professional footballers during the English Premiership season. Players volunteered to wear a triaxial wrist accelerometer for 1 week, removing it only for training and matches. In total, 25 players met the inclusion criteria for analysis. Players recorded on average 632.6 min wear time p/day during the post-training period (SD±52.9) for a mean of 3.8 days (SD±1.5). Results On average, players recorded 76.2 min p/day (SD±28.8) of moderate or vigorous activity post-training. The majority (79%) of post-training time was spent in sedentary activities (500.6 min per day±59.0). Conclusions Professional footballers are alarmingly sedentary in their leisure time, and comparatively more so than non-athletic groups of a similar age and older. This raises questions over optimum recovery and performance, as well as long-term health and cardiovascular risk. Worryingly, retirement from elite sport is likely to further imbalance activity and sedentary behaviour. Promoting regular periodic light to moderate leisure time activity could be beneficial. Further research and provision of education and support for players is required in this area.

Aggio et al. Respond to “Lessons for Research on Cognitive Aging”

We thank Dr. Belsky (1) for his interest in our study (2), in which we investigated associations between physical activity and cognitive function in young people. He raises several important issues on the role of physical activity as a public health strategy in the prevention of cognitive decline. The issue of “neuroselection,” wherein individuals with better cognitive function are more likely to engage in healthy behaviors such as physical activity and refrain from unhealthy ones such as smoking, is a potential source of bias in observational studies. The alternative hypothesis is that of “neuroprotection,” in which engagement in healthy behaviors is likely to lead to enhanced cognitive development. We agree that confounding by pre-existing characteristics is a general problem in any epidemiologic work. Indeed, the children in our accelerometry sample typically came from wealthier families and had parents with higher levels of education than did those excluded from the analysis. Neuroselection may also explain the associations observed between physical activity and cognitive function. Longitudinal studies provide an opportunity to investigate whether cognitive function at baseline is associated with positive health behaviors in later life. For example, children with better cognitive function demonstrate higher fitness levels in adulthood (3). One potential mechanism may be that individuals with superior cognitive function are better able to interpret and respond to health advice than are individuals with lower cognitive function (4). The basis of the neuroselection hypothesis is that individuals with higher cognitive function elect to live healthier lives. However, in our study (2), physical activity was measured at age 7 years, meaning that if the neuroselection argument were true, children with higher cognitive function would already be selecting to be active at this early age. Childrens knowledge of healthy behaviors is limited in this age group (5), which suggests that young children may not be able to correctly identify healthy behaviors regardless of cognitive ability. Moreover, during early childhood, self-selection of healthy behaviors may be restricted because of the low levels of autonomy due to school policy and parental restrictions. Physical activity at this age is predominantly influenced by parents and the school environment (6, 7). Therefore, participation in healthy behaviors among young children is largely determined by their parents’ and teachers’ decisions rather than their own. Adolescents and young adults have high levels of independence and therefore the ability to respond to new information independently. Together, these points suggest that the process of neuroselection is more likely to occur from adolescence onwards than in childhood. Further longitudinal studies with multiple repeated measures of health behaviors and cognitive function throughout childhood and adolescence are needed to address this hypothesis. Dr. Belsky raises an important point relating to the inconsistent effects of exercise on cognitive function that have been observed in recent randomized trials. This suggests that successful interventions may need to utilize physical activity in ways that also engage the brain. Indeed, this also emphasizes the main finding from our study, which was the importance of the context of physical activity and sedentary behavior in their associations with cognitive function. There is also research demonstrating the importance of context on other health outcomes. Notably, in a recent prospective study, childhood membership in a club was associated with a lower risk of mortality in adulthood that was independent of physical activity levels (8). In summary, physical activity is a potential public health strategy for the prevention of neurodegenerative diseases, and early life may represent a crucial period for intervention. Further investigation on effects of specific types and domains of activity is warranted.

‘On Your Feet to Earn Your Seat’: update to randomised controlled trial protocol

BackgroundThis update describes changes to procedures for our randomised controlled trial of ‘On Your Feet to Earn Your Seat’, a habit-based intervention to reduce sedentary behaviour in older adults. Some of the amendments have arisen from the addition of new sites, each offering different possibilities and constraints for study procedures. Others have been made in response to problems encountered in administering intended recruitment procedures at the London sites described in our original protocol. All changes have received ethics and governance clearance, and were made before or during data collection and prior to analyses.Methods/designFive non-London UK NHS-based sites (three general practices, one hospital, one NHS Foundation Trust) have been added to the study, each employing locally-tailored variations of recruitment and data collection procedures followed at the London sites. In contrast to the London sites, accelerometry data are not being collected nor are shopping vouchers being given to participants at the new sites. Data collection was delayed at the London sites because of technical difficulties in contacting participants. Subsequently, a below-target sample size was achieved at the London sites (n = 23), and recruitment rates cannot be estimated. Additionally, the physical inactivity inclusion criterion (i.e., <30 consecutive minutes of leisure time activity) has been removed from all sites, because we found that participants at the London sites meeting this criterion at consent subsequently reported activity above this threshold at the baseline assessment.ConclusionThis is primarily a feasibility trial. The addition of new sites, each employing different study procedures, offers the opportunity to assess the feasibility of alternative recruitment and data collection methods, so enriching the informational value of our analyses of primary outcomes. Recruitment has finished, and the coincidence of a small sample at the London sites with addition of new sites has ensured a final sample size similar to our original target.Trial registrationCurrent Controlled Trials ISRCTN47901994 (registration date: 16th January 2014)

Longitudinal patterns in objective physical activity and sedentary time in a multi‐ethnic sample of children from the UK

Children of South Asian decent born in the UK display lower levels of physical activity than British Caucasians although no longitudinal data are available.

Objectively measured daily physical activity and postural changes as related to positive and negative affect using ambulatory monitoring assessments

Objective The aim of the study was to determine whether objectively measured daily physical activity and posture of sitting, standing, and sit-to-stand transitions are associated with daily assessments of affect. Methods Participants (N = 51, 49% female) wore ActivPal accelerometers for 24 h/d for seven consecutive days. Time spent sitting, standing, and being physically active and sit-to-stand transitions were derived for each day. Participants also completed a mood inventory each evening. Multilevel models examined within- and between-person associations of daily physical activity with positive and negative affect, adjusting for age, sex, body mass index, education, and sleep duration. Results Within-person associations showed that a 1-hour increase in daily physical activity was associated with a decrease in negative affect over the same day (B = −0.11, 95% confidence interval [CI], −0.21 to −0.01). Between-person associations indicated a borderline significant association between higher average daily physical activity levels and higher positive affect (B = 1.85, 95% CI = −0.25 to 3.94). There were no between- or within-person associations between sitting, standing, and sit-to-stand transitions with affect. Conclusions Promoting physical activity may be a potential intervention strategy to acutely suppress negative affective states.