A cluster randomised controlled trial to investigate the effectiveness and cost effectiveness of the 'Girls Active' intervention: a study protocol.

BACKGROUND: Despite the health benefits of physical activity, data from the UK suggest that a large proportion of adolescents do not meet the recommended levels of moderate-to-vigorous physical activity (MVPA). This is particularly evident in girls, who are less active than boys across all ages and may display a faster rate of decline in physical activity throughout adolescence. The 'Girls Active' intervention has been designed by the Youth Sport Trust to target the lower participation rates observed in adolescent girls. 'Girls Active' uses peer leadership and marketing to empower girls to influence decision making in their school, develop as role models and promote physical activity to other girls. Schools are provided with training and resources to review their physical activity, sport and PE provision, culture and practices to ensure they are relevant and attractive to adolescent girls. METHODS/DESIGN: This study is a two-arm cluster randomised controlled trial (RCT) aiming to recruit 20 secondary schools. Clusters will be randomised at the school level (stratified by school size and proportion of Black and Minority Ethnic (BME) pupils) to receive either the 'Girls Active' intervention or carry on with usual practice (1:1). The 20 secondary schools will be recruited from state secondary schools within the Midlands area. We aim to recruit 80 girls aged 11-14 years in each school. Data will be collected at three time points; baseline and seven and 14 months after baseline. Our primary aim is to investigate whether 'Girls Active' leads to higher objectively measured (GENEActiv) moderate-to-vigorous physical activity in adolescent girls at 14 months after baseline assessment compared to the control group. Secondary outcomes include other objectively measured physical activity variables, adiposity, physical activity-related psychological factors and the cost-effectiveness of the 'Girls Active' intervention. A thorough process evaluation will be conducted during the course of the intervention delivery. DISCUSSION: The findings of this study will provide valuable information on whether this type of school-based approach to increasing physical activity in adolescent girls is both effective and cost-effective in the UK. TRIAL REGISTRATION: ISRCTN10688342. Registered 12 January 2015.

Type 2 diabetes mellitus and obesity in young adults: the extreme phenotype with early cardiovascular dysfunction.

AIM: A pilot study to phenotype young adults (< 40 years) with Type 2 diabetes mellitus. METHODS: Twenty people with Type 2 diabetes (aged 18-40 years), 10 lean and 10 obese control subjects underwent detailed assessment, including tagged cardiac magnetic resonance imaging, inflammatory proteins, lipids, vitamin D and maximal oxygen uptake. Outcomes were compared between the group with Type 2 diabetes and the control group. RESULTS: Mean (standard deviation) age, Type 2 diabetes duration and BMI in the group with Type 2 diabetes were 31.8 (6.6) years, 4.7 (4.0) years and 33.9 (5.8) kg/m(2) respectively. Compared with lean control subjects, those with Type 2 diabetes had more deleterious profiles of hyperlipidaemia, vitamin D deficiency, inflammation and maximal oxygen uptake relative to body mass. However, there was no difference between the group with Type 2 diabetes and the obese control group. The group with Type 2 diabetes had a higher left ventricular mass and a trend towards concentric remodelling compared with the lean control group (P = 0.002, P = 0.052) but not the obese control group (P > 0.05). Peak early diastolic strain rate was reduced in the group with Type 2 diabetes [1.51 (0.24)/s] compared with the lean control [1.97 (0.34)/s, P = 0.001] and obese control [1.78 (0.39)/s, P = 0.042] group. CONCLUSIONS: Young adults with Type 2 diabetes and those with obesity have similar adverse cardiovascular risk profiles, higher left ventricular mass and a trend towards left ventricular concentric remodelling. In addition, those with Type 2 diabetes demonstrate diastolic dysfunction, a known risk marker for future heart failure and mortality.

Associations of objectively measured sedentary behaviour and physical activity with markers of cardiometabolic health.

AIMS/HYPOTHESIS: The study aimed to examine the associations between objectively measured sedentary time, breaks in sedentary time, moderate-to-vigorous physical activity (MVPA) and total physical activity with markers of cardiometabolic health in a population with known risk factors for type 2 diabetes mellitus. METHODS: This study reports data from two ongoing diabetes prevention programmes. Participants with known risk factors were recruited from primary care practices located within the East Midlands, UK, over the period 2010-2011. ActiGraph GT3X accelerometers (15 s epochs) were used to assess sedentary time (<25 counts per 15 s), MVPA (≥ 488 counts per 15 s) and total physical activity (total counts). A break was considered as any interruption in sedentary time (≥ 25 counts per 15 s). Linear regression examined the independent association of sedentary time, breaks in sedentary time, MVPA and total physical activity with markers of cardiometabolic health. RESULTS: The sample comprised 878 participants; 153 from Project STAND (Sedentary Time And Diabetes) (age 32.9 ± 5.6 years, 28.8% male) and 725 from Walking Away from Diabetes (age 63.7 ± 7.8 years, 64.8% male). Following adjustment for various covariates, including MVPA and BMI, there were detrimental linear associations of sedentary time with 2 h plasma glucose (standardised beta coefficient) (ß = 0.220, p < 0.001), triacylglycerol (ß = 0.206, p = 0.001) and HDL-cholesterol (ß = -0.123, p = 0.029). Breaks in sedentary time, total physical activity and MVPA were significantly inversely associated with measures of adiposity, but not with any other cardiometabolic variables after adjustment for sedentary time and BMI. CONCLUSIONS/INTERPRETATION: In adults at high risk of type 2 diabetes mellitus, time spent sedentary is strongly and adversely associated with cardiometabolic health and may be a more important indicator of poor health than MVPA.

Prevalence of diabetes and impaired glucose metabolism in younger 'at risk' UK adults: insights from the STAND programme of research.

AIMS: Rising rates of obesity have led to an increasing prevalence of Type 2 diabetes mellitus in young people. Uncertainty exists over the utility of screening younger adults for Type 2 diabetes, as existing data sets have focused on mature (> 40 years) cohorts. The aim of this study was to determine the prevalence of impaired glucose metabolism in higher risk younger adults. METHODS: Overweight (with an additional risk factor) or obese adults (18-40 years) were recruited for the Sedentary Time And Diabetes (STAND) randomized controlled trial. Measures included an oral glucose tolerance test, HbA1c , biochemical and anthropometric data. RESULTS: One hundred and ninety-three individuals (68% female; median age 33.8 years; median BMI 33.9 kg/m²) were recruited. Forty-three per cent had a first-degree family history of Type 2 diabetes. Previously undiagnosed Type 2 diabetes was present in 4.7% (n = 9). Of participants, 18.1% (n = 35) had impaired glucose metabolism: 4.7% (n = 9) HbA1c ≥ 48 mmol/mol (6.5%); 9.3% (n = 18) HbA1c 42-46 mmol/mol (6.0-6.4%); 3.1% (n = 6) Type 2 diabetes on oral glucose tolerance test; 6.2% (n = 12) isolated impaired glucose tolerance; 2.1% (n = 4) isolated impaired fasting glucose; 1% (n = 2) both impaired fasting glucose and impaired glucose tolerance. Of participants, 58.5% (n = 113) had dyslipidaemia, 28.0% (n = 54) had hypertension, 31.1% (n = 60) were vitamin D deficient and 7.3% (n = 14) had abnormal liver function. CONCLUSIONS: This study identified a high prevalence of Type 2 diabetes and impaired glucose regulation in overweight and obese younger adults. These findings require confirmation in a larger, representative, population.

Sedentary time in adults and the association with diabetes, cardiovascular disease and death: systematic review and meta-analysis.

AIMS/HYPOTHESIS: Sedentary (sitting) behaviours are ubiquitous in modern society. We conducted a systematic review and meta-analysis to examine the association of sedentary time with diabetes, cardiovascular disease and cardiovascular and all-cause mortality. METHODS: Medline, Embase and the Cochrane Library databases were searched for terms related to sedentary time and health outcomes. Cross-sectional and prospective studies were included. RR/HR and 95% CIs were extracted by two independent reviewers. Data were adjusted for baseline event rate and pooled using a random-effects model. Bayesian predictive effects and intervals were calculated to indicate the variance in outcomes that would be expected if new studies were conducted in the future. RESULTS: Eighteen studies (16 prospective, two cross-sectional) were included, with 794,577 participants. Fifteen of these studies were moderate to high quality. The greatest sedentary time compared with the lowest was associated with a 112% increase in the RR of diabetes (RR 2.12; 95% credible interval [CrI] 1.61, 2.78), a 147% increase in the RR of cardiovascular events (RR 2.47; 95% CI 1.44, 4.24), a 90% increase in the risk of cardiovascular mortality (HR 1.90; 95% CrI 1.36, 2.66) and a 49% increase in the risk of all-cause mortality (HR 1.49; 95% CrI 1.14, 2.03). The predictive effects and intervals were only significant for diabetes. CONCLUSIONS/INTERPRETATION: Sedentary time is associated with an increased risk of diabetes, cardiovascular disease and cardiovascular and all-cause mortality; the strength of the association is most consistent for diabetes.

The Pre-diabetes Risk Education and Physical Activity Recommendation and Encouragement (PREPARE) programme study: are improvements in glucose regulation sustained at 2 years?

OBJECTIVE: To determine whether improvements in glucose regulation following the PREPARE structured education programme were sustained at 24 months. PATIENTS AND METHODS: Ninety-eight overweight or obese individuals with impaired glucose tolerance were randomized to receive: (1) advice leaflet, (2) 3-h structured education programme aimed at promoting physical activity, (iii) 3-h structured education with personalized pedometer use. The primary outcome was change in 2-h post-challenge plasma glucose. RESULTS: Seventy-three (74%) individuals were included for analysis at 24 months; age 65 ± 8 years, BMI 29.3 ± 4.8 kg/m(2), South Asian ethnicity 21%. A statistically significant reduction in 2-h glucose of -1.6 mmol/l (-0.4 to -2.7) was seen in the education-with-pedometer group compared with the control group. There is no significant difference in the education-only group. CONCLUSION: Improvements in glucose regulation following a pragmatic group-based structured education with pedometer use were sustained at 24 months.

The effect of increased ambulatory activity on markers of chronic low-grade inflammation: evidence from the PREPARE programme randomized controlled trial.

AIMS: To investigate whether an exercise intervention programme, with or without pedometer use, is effective at reducing chronic low-grade inflammation in those with impaired glucose tolerance. METHODS: Using baseline and 12-month data from the Pre-diabetes Risk Education and Physical Activity Recommendation and Encouragement (PREPARE) programme randomized controlled trial, we investigated whether the pedometer or the standard version of the PREPARE programme is associated with reduced chronic low-grade inflammation. Outcomes included interleukin-6, C-reactive protein, fasting and 2 h post-challenge glucose values and objectively measured ambulatory activity. RESULTS: Seventy-four participants (31% female; mean age, 65 years; body mass index, 29.3 ± 4.8 kg/m(2) ) were included, of which 26 were in the control group and 24 were in each intervention group. At 12 months there was an increase in ambulatory activity of 1351 and 1849 steps/day in the standard and pedometer group, respectively, compared with control conditions; however, there was no significant change in markers of chronic low-grade inflammation. Across the pooled study sample, change in ambulatory activity was significantly correlated with change in interleukin-6 (r = -0.32, P = 0.01) after adjustment for group, age, sex, ethnicity, aspirin and statin medication, baseline body mass index and change in body mass index. Change in interleukin-6 was also significantly correlated with change in 2 h glucose after adjustment for the same variables (r = 0.26, P = 0.03). CONCLUSIONS: This study failed to show reductions in markers of chronic low-grade inflammation following an intervention that promoted modest increases in ambulatory activity; however, across the study sample, increased ambulatory activity was associated with reduced interleukin-6, independent of obesity.

The role of physical activity in the management of impaired glucose tolerance: a systematic review.

Although physical activity is widely reported to reduce the risk of type 2 diabetes in individuals with prediabetes, few studies have examined this issue independently of other lifestyle modifications. The aim of this review is to conduct a systematic review of controlled trials to determine the independent effect of exercise on glucose levels and risk of type 2 diabetes in people with prediabetes (IGT and/or IFG). A detailed search of MEDLINE (1966-2006) and EMBASE (1980-2006) found 279 potentially relevant studies, eight of which met the inclusion criteria for this review. All eight studies were controlled trials in individuals with impaired glucose tolerance. Seven studies used a multi-component lifestyle intervention that included exercise, diet and weight loss goals and one used a structured exercise training intervention. Four studies used the incidence of diabetes over the course of the study as an outcome variable and four relied on 2-h plasma glucose as an outcome measure. In the four studies that measured the incidence of diabetes as an outcome, the risk of diabetes was reduced by approximately 50% (range 42-63%); as these studies reported only small changes in physical activity levels, the reduced risk of diabetes is likely to be attributable to factors other than physical activity. In the remaining four studies, only one reported significant improvements in 2-h plasma glucose even though all but one reported small to moderate increases in maximal oxygen uptake. These results indicate that the contribution of physical activity independent of dietary or weight loss changes to the prevention of type 2 diabetes in people with prediabetes is equivocal.

Relationships between media use, body fatness and physical activity in children and youth: a meta-analysis.

OBJECTIVE: To review the empirical evidence of associations between television (TV) viewing, video/computer game use and (a) body fatness, and (b) physical activity. DESIGN: Meta-analysis. METHOD: Published English-language studies were located from computerized literature searches, bibliographies of primary studies and narrative reviews, and manual searches of personal archives. Included studies presented at least one empirical association between TV viewing, video/computer game use and body fatness or physical activity among samples of children and youth aged 3-18 y. MAIN OUTCOME MEASURE: The mean sample-weighted corrected effect size (Pearson r). RESULTS: Based on data from 52 independent samples, the mean sample-weighted effect size between TV viewing and body fatness was 0.066 (95% CI=0.056-0.078; total N=44,707). The sample-weighted fully corrected effect size was 0.084. Based on data from six independent samples, the mean sample-weighted effect size between video/computer game use and body fatness was 0.070 (95% CI=-0.048 to 0.188; total N=1,722). The sample-weighted fully corrected effect size was 0.128. Based on data from 39 independent samples, the mean sample-weighted effect size between TV viewing and physical activity was -0.096 (95% CI=-0.080 to -0.112; total N=141,505). The sample-weighted fully corrected effect size was -0.129. Based on data from 10 independent samples, the mean sample-weighted effect size between video/computer game use and physical activity was -0.104 (95% CI=-0.080 to -0.128; total N=119,942). The sample-weighted fully corrected effect size was -0.141. CONCLUSION: A statistically significant relationship exists between TV viewing and body fatness among children and youth although it is likely to be too small to be of substantial clinical relevance. The relationship between TV viewing and physical activity is small but negative. The strength of these relationships remains virtually unchanged even after correcting for common sources of bias known to impact study outcomes. While the total amount of time per day engaged in sedentary behavior is inevitably prohibitive of physical activity, media-based inactivity may be unfairly implicated in recent epidemiologic trends of overweight and obesity among children and youth. Relationships between sedentary behavior and health are unlikely to be explained using single markers of inactivity, such as TV viewing or video/computer game use.

Pubertal development and sedentary behaviour during adolescence.

BACKGROUND: Assessing time spent in sedentary behaviours in relation to pubertal status, anthropometric differences, and body image will improve insight into the prevalence and determinants of such behaviours during adolescence. AIM: The study aimed to investigate the effects of age, puberty, gender, body composition, and sleep on sedentary behaviour. PARTICIPANTS AND METHODS: Participants were 64 boys and 55 girls in Year 6 (10.0-10.9 years of age), Year 8 (12.0-12.9 years) and Year 10 (14.0-14.9 years). Body mass index and percentage body fat were calculated from anthropometric measures. Sedentary behaviour and sleep time were computed using momentary-time sampling. Body image was measured using the Children's Physical Self-Perception Profile. Pubertal status was assessed from self-report of secondary sexual characteristics. RESULTS: After controlling for sleep time, no differences in sedentary time were seen for puberty onset or increased pubertal development. Correlations between pubertal status, body composition, and body image were stronger in girls than in boys. Correlations between body image and sedentary behaviour were not strong enough to infer behavioural choice differences. CONCLUSIONS: Reduced sleep time rather than changing body image and body composition during adolescence is associated with greater sedentary behaviour.

Exercise behaviour change in 40 to 65-year-old women: The SWEAT Study (Sedentary Women Exercise Adherence Trial).

OBJECTIVE: The purpose of this study was to examine the relation between self-reported psychological processes and changes in exercise behaviour in an 18-month longitudinal stage-based intervention trial in 115 initially sedentary women aged 40-65 years. DESIGN: A two-way factorial design was used. METHODS: Participants were assigned randomly to either moderate or vigorous and either home or centre-based exercise. After six months, all participants exercised at home. Participants completed questionnaires at baseline, six, 12 and 18 months which assessed stage of exercise behaviour, self-efficacy, decisional balance and processes of change. RESULTS: 28 patterns of stage change were identified across the 18 months with 6.1% remaining sedentary and 45% demonstrating linear movement from contemplation to action to maintenance to continued maintenance. Two interpretable clusters were identified within both the contemplation (at baseline) and action (at six months) stages. Cluster membership, however, did not influence behaviour change. For participants demonstrating a linear pattern of change, self-efficacy for overcoming barriers and behavioural processes increased from contemplation to action. Self-efficacy for exercise competence increased from contemplation to action but was more pronounced for the vigorous exercise groups. Decisional balance showed a three-way interaction and there was no change for experimental processes. There was no change in any variable from action to maintenance. CONCLUSIONS: The intervention was seen to be effective regardless of location or intensity of exercise. The relevance of substages is questionable in stage-based interventions as women with a profile suggesting less readiness to change or sustain change were just as likely to adopt or maintain exercise.

Controlled comparison of retention and adherence in home- vs center-initiated exercise interventions in women ages 40-65 years: The S.W.E.A.T. Study (Sedentary Women Exercise Adherence Trial).

BACKGROUND: In an 18-month exercise intervention in previously sedentary older women (40-65 years), we examined whether an initial 6 months of supervised exercise leads to greater long-term retention and adherence to regular physical activity than an unsupervised home-based program and whether these outcomes are influenced by the exercise intensity. METHODS: Women (N = 126) were recruited from the community and randomly assigned to either center-based or home-based exercise three times/week. The center-based group attended supervised sessions for 6 months, while after 10 initial sessions the home-based group exercised at home. After 6 months both groups were home-based for a further 12 months. Within each arm, subjects were further randomized to exercise at either moderate or vigorous intensity. RESULTS: The center-based group had higher retention than the home-based (97, 94, 81 versus 87, 76, and 61%) at 6, 12, and 18 months, respectively (P < 0.05). At 6 months, adherence was higher in the center-based group (84 versus 63%, P < 0.001) and energy expenditure was higher at 6 (P < 0.05) and 12 (P < 0.01) months. At 18 months, retention was higher with moderate exercise (P < 0.05), while adherence was similar with both intensities. CONCLUSION: An initial 6 months of center-based exercise enhanced retention in both the short and the long term and promoted short-term adherence and energy expenditure. Long-term, moderate exercise retained more subjects, but had little influence on adherence.