Rehabilitation Support via Postcard (RSVP): A Randomised Controlled Trial of a Postcard to Promote Uptake of Cardiac Rehabilitation.

PURPOSE: The aim was to increase cardiac rehabilitation (CR) uptake using a novel intervention, Rehabilitation Support Via Postcard (RSVP), among patients with acute myocardial infarction discharged from two major hospitals in Hunter New England Local Health District (HNELHD), New South Wales, Australia. METHODS: The RSVP trial was evaluated using a two-armed randomised controlled trial design. Participants (N=430) were recruited from the two main hospitals in HNELHD, and enrolled and randomised to either the intervention (n=216) or control (n=214) group over a six-month period. All participants received usual care; however, the intervention group received postcards promoting CR attendance between January and July 2020. The postcard was ostensibly written as an invitation from the patient's admitting medical officer to promote timely and early uptake of CR. The primary outcome was CR attendance at outpatient HNELHD CR services in the 30-days post-discharge. RESULTS: Fifty-four percent (54%) of participants who received RSVP attended CR, compared to 46% in the control group; however this difference was not statistically significant (odds ratio [OR]=1.4, 95% confidence interval [CI]=0.9-2.0, p=0.11). Exploratory post-hoc analysis among four sub-groups (i.e., Indigeneity, gender, age and rurality), found that the intervention significantly increased attendance in males (OR=1.6, 95%CI=1.0-2.6, p=0.03) but had no significant impact on attendance for other sub-groups. CONCLUSIONS: While not statistically significant, postcards increased overall CR attendance by 8%. This strategy may be useful to increase attendance, particularly in men. Alternative strategies are necessary to increase CR uptake among women, Indigenous people, older people and people from regional and remote locations.

The effects of the eCoFit RCT on depression and anxiety symptoms among adults with or at risk of Type 2 Diabetes.

Participation in regular physical activity has significant physical, psychological, and social benefits, including the prevention and treatment of Type 2 Diabetes (T2D). The primary aim of this paper was to evaluate the impact of theeCoFit physical activity intervention on depression and anxiety symptoms among adults at risk of, or diagnosed with, T2D. The primary outcomes were assessed using Patient Health Questionnaire-9, and Generalised Anxiety Disorder-7. The secondary aim was to test for the potential mediators for the intervention effect on mental health. The 20-week intervention was evaluated using a two-arm randomised controlled trial with await list control group. The intervention included two phases: Phase 1 integrated group face-to-face sessions and the use of the eCoFit smartphone application (app); and Phase 2 that included the use of the app only. Participants (n = 84) were assessed at baseline and 10- and 20-weeks post-baseline. Social support, self-efficacy, nature-relatedness, and perceived sleep quality were examined as potential mechanisms for the intervention effects on mental health. A significant interaction for depression severity was observed at 20-weeks (-1.76, CI -3.48, -05, p= .044, d= -0.35). There were no significant intervention effects for anxiety or any of the potential mechanisms.

Effect of a physical activity and sleep m-health intervention on a composite activity-sleep behaviour score and mental health: a mediation analysis of two randomised controlled trials.

BACKGROUND: To examine if a composite activity-sleep behaviour index (ASI) mediates the effects of a combined physical activity and sleep intervention on symptoms of depression, anxiety, or stress, quality of life (QOL), energy and fatigue in adults. METHODS: This analysis used data pooled from two studies: Synergy and Refresh. Synergy: Physically inactive adults (18-65 years) who reported poor sleep quality were recruited for a two-arm Randomised Controlled Trial (RCT) (Physical Activity and Sleep Health (PAS; n = 80), or Wait-list Control (CON; n = 80) groups). Refresh: Physically inactive adults (40-65 years) who reported poor sleep quality were recruited for a three-arm RCT (PAS (n = 110), Sleep Health-Only (SO; n = 110) or CON (n = 55) groups). The SO group was omitted from this study. The PAS groups received a pedometer, and accessed a smartphone/tablet "app" using behaviour change strategies (e.g., self-monitoring, goal setting, action planning), with additional email/SMS support. The ASI score comprised self-reported moderate-to-vigorous-intensity physical activity, resistance training, sitting time, sleep duration, efficiency, quality and timing. Outcomes were assessed using DASS-21 (depression, anxiety, stress), SF-12 (QOL-physical, QOL-mental) and SF-36 (Energy & Fatigue). Assessments were conducted at baseline, 3 months (primary time-point), and 6 months. Mediation effects were examined using Structural Equation Modelling and the product of coefficients approach (AB), with significance set at 0.05. RESULTS: At 3 months there were no direct intervention effects on mental health, QOL or energy and fatigue (all p > 0.05), and the intervention significantly improved the ASI (all p < 0.05). A more favourable ASI score was associated with improved symptoms of depression, anxiety, stress, QOL-mental and of energy and fatigue (all p < 0.05). The intervention effects on symptoms of depression ([AB; 95%CI] -0.31; - 0.60,-0.11), anxiety (- 0.11; - 0.27,-0.01), stress (- 0.37; - 0.65,-0.174), QOL-mental (0.53; 0.22, 1.01) and ratings of energy and fatigue (0.85; 0.33, 1.63) were mediated by ASI. At 6 months the magnitude of association was larger although the overall pattern of results remained similar. CONCLUSIONS: Improvements in the overall physical activity and sleep behaviours of adults partially mediated the intervention effects on mental health and quality of life outcomes. This highlights the potential benefit of improving the overall pattern of physical activity and sleep on these outcomes. TRIAL REGISTRATION: Australian New Zealand Clinical Trial Registry: ACTRN12617000680369 ; ACTRN12617000376347 . Universal Trial number: U1111-1194-2680; U1111-1186-6588. Human Research Ethics Committee Approval: H-2016-0267; H-2016-0181.

Examining social-cognitive theory constructs as mediators of behaviour change in the active team smartphone physical activity program: a mediation analysis.

BACKGROUND: Regular engagement in physical activity has well-established physical and psychological health benefits. Despite this, over a quarter of the global adult population is insufficiently physically active. Physical activity interventions grounded in behaviour change theory, such as the social-cognitive theory, are widely considered to be more effective than non-theoretical approaches. Such interventions set out to intervene on the ultimate outcome (physical activity), but also influence intermediate factors (social-cognitive theory constructs) which in turn, are believed to influence physical activity behaviour. The primary aim of the study was to use mediation analysis to examine whether changes in the social-cognitive theory and related constructs, in particular self-efficacy, outcome expectations, intentions, barriers and goal setting, mediated the effects of a smartphone-based social networking physical activity intervention. METHODS: Mediation analyses were conducted using the PROCESS Macro in SPSS to (i) calculate the regression coefficients for the effect of the independent variable (group allocation) on the hypothesised mediators (social-cognitive theory constructs), (ii) calculate the regression coefficient for the effect of the hypothesised mediators (social-cognitive theory constructs) on the dependent variable (objectively measured physical activity or self-report physical activity), independent of group assignment and (iii) determine the total, direct and indirect intervention effects. RESULTS: Data from 243 participants were included in the mediation analysis. There was no evidence of mediation for change in objectively measured MVPA or self-reported MVPA. CONCLUSIONS: There was no conclusive evidence that any of the social-cognitive theory constructs mediated the relationship between an app-based intervention and change in physical activity. Ongoing efforts to develop and understand components that make physical activity app-based interventions effective are recommended. TRIAL REGISTRATION: This trial was registered with the Australian and New Zealand Clinical Trial Registry ( ACTRN12617000113358 , date of registration 23 January, 2017).

Are web-based personally tailored physical activity videos more effective than personally tailored text-based interventions? Results from the three-arm randomised controlled TaylorActive trial.

OBJECTIVES: Some online, personally tailored, text-based physical activity interventions have proven effective. However, people tend to 'skim' and 'scan' web-based text rather than thoroughly read their contents. In contrast, online videos are more engaging and popular. We examined whether web-based personally tailored physical activity videos were more effective in promoting physical activity than personally tailored text and generic information. METHODS: 501 adults were randomised into a video-tailored intervention, text-tailored intervention or control. Over a 3-month period, intervention groups received access to eight sessions of web-based personally tailored physical activity advice. Only the delivery method differed between intervention groups: tailored video versus tailored text. The primary outcome was 7-day ActiGraph-GT3X+ measured moderate-to-vigorous physical activity (MVPA) assessed at 0, 3 and 9 months. Secondary outcomes included self-reported MVPA and website engagement. Differences were examined using generalised linear mixed models with intention-to-treat and multiple imputation. RESULTS: Accelerometer-assessed MVPA increased 23% in the control (1.23 (1.06, 1.43)), 12% in the text-tailored (1.12 (0.95, 1.32)) and 28% in the video-tailored (1.28 (1.06, 1.53)) groups at the 3-month follow-up only, though there were no significant between-group differences. Both text-tailored (1.77 (1.37, 2.28]) and video-tailored (1.37 (1.04, 1.79)) groups significantly increased self-reported MVPA more than the control group at 3 months only, but there were no differences between video-tailored and text-tailored groups. The video-tailored group spent significantly more time on the website compared with text-tailored participants (90 vs 77 min, p=0.02). CONCLUSIONS: The personally tailored videos were not more effective than personally tailored text in increasing MVPA. The findings from this study conflict with pilot study outcomes and previous literature. Process evaluation and mediation analyses will provide further insights. TRIAL REGISTRATION NUMBER: ACTRN12615000057583.

Efficacy of an m-Health Physical Activity and Sleep Intervention to Improve Sleep Quality in Middle-Aged Adults: The Refresh Study Randomized Controlled Trial.

BACKGROUND: Poor sleep health is highly prevalent. Physical activity is known to improve sleep quality but not specifically targeted in sleep interventions. PURPOSE: To compare the efficacy of a combined physical activity and sleep intervention with a sleep-only intervention and a wait-list control, for improving sleep quality in middle-aged adults without a diagnosed sleep disorder. METHODS: Three-arm randomized controlled trial (Physical Activity and Sleep Health (PAS), Sleep Health Only (SO), Wait-list Control (CON) groups; 3-month primary time-point, 6-month follow-up) of 275 (PAS = 110, SO = 110, CON = 55) inactive adults (40-65 years) reporting poor sleep quality. The main intervention component was a smartphone/tablet "app" to aid goal setting and self-monitoring physical activity and/or sleep hygiene behaviors (including stress management), and a pedometer for PAS group. Primary outcome was Pittsburgh Sleep Quality Index (PSQI) global score. Secondary outcomes included several self-reported physical activity measures and PSQI subcomponents. Group differences were examined stepwise, first between pooled intervention (PI = PAS + SO) and CON groups, then between PAS and SO groups. RESULTS: Compared with CON, PI groups significantly improved PSQI global and subcomponents scores at 3 and 6 months. There were no differences in sleep quality between PAS and SO groups. The PAS group reported significantly less daily sitting time at 3 months and was significantly more likely to report ≥2 days/week resistance training and meeting physical activity guidelines at 6 months than the SO group. CONCLUSIONS: PIs had statistically significantly improved sleep quality among middle-aged adults with poor sleep quality without a diagnosed sleep disorder. The adjunctive physical activity intervention did not additionally improve sleep quality. CLINICAL TRIAL INFORMATION: Australian New Zealand Clinical Trial Registry: ACTRN12617000680369; Universal Trial number: U1111-1194-2680; Human Research Ethics Committee, Blinded by request of journal: H-2016-0267.

Momentary mood predicts upcoming real-life sedentary behavior.

Humans in the industrialized world spend a large amount of daily time in sedentary behavior. Since sedentariness negatively impacts a variety of psychophysiological outcomes, the identification of antecedents that lead to sedentary behavior is an important public health issue. In this context, mood, a central indicator for both psychological well-being and mental health, is severely understudied. To investigate whether mood dimensions influence subsequent sedentary behavior, we assessed both constructs at baseline via questionnaires and via ambulatory assessment (AA) over 5 days in 92 university employees. We continuously measured sedentary behavior using accelerometers and assessed mood repeatedly 10 times each day on smartphone diaries. We employed multiple regression analyses to analyze between-subject effects and multilevel modeling to analyze within-subject effects. Higher momentary ratings of valence (P < .05) and energetic arousal (P < .01) predicted lower amounts of subsequent sedentary behavior, whereas higher ratings of calmness (P < .01) predicted higher amounts of subsequent sedentary behavior. The context moderated the effect of energetic arousal and calmness on sedentary behavior with increased effects in the home compared to the work context. Mood significantly predicted sedentary behavior on a within-subject level but not on a between-subject level. Preliminary evidence suggests that mood regulates sedentary behavior in everyday life. Time-sensitive analyses, such as from moment to moment revealed an association between mood and sedentary behavior (within-subject), whereas analyses between different individuals revealed no associations (between-subject). These preliminary findings may inform multicomponent intervention strategies that target mood, to reduce sedentary behavior in daily life.

Time-efficient intervention to improve older adolescents' cardiorespiratory fitness: findings from the 'Burn 2 Learn' cluster randomised controlled trial.

BACKGROUND: Cardiorespiratory fitness (CRF) is an important marker of current and future health status. The primary aim of our study was to evaluate the impact of a time-efficient school-based intervention on older adolescents' CRF. METHODS: Two-arm cluster randomised controlled trial conducted in two cohorts (February 2018 to February 2019 and February 2019 to February 2020) in New South Wales, Australia. Participants (N=670, 44.6% women, 16.0±0.43 years) from 20 secondary schools: 10 schools (337 participants) were randomised to the Burn 2 Learn (B2L) intervention and 10 schools (333 participants) to the control. Teachers in schools allocated to the B2L intervention were provided with training, resources, and support to facilitate the delivery of high-intensity interval training (HIIT) activity breaks during curriculum time. Teachers and students in the control group continued their usual practice. The primary outcome was CRF (20 m multi-stage fitness test). Secondary outcomes were muscular fitness, physical activity, hair cortisol concentrations, mental health and cognitive function. Outcomes were assessed at baseline, 6 months (primary end-point) and 12 months. Effects were estimated using mixed models accounting for clustering. RESULTS: We observed a group-by-time effect for CRF (difference=4.1 laps, 95% CI 1.8 to 6.4) at the primary end-point (6 months), but not at 12 months. At 6 months, group-by-time effects were found for muscular fitness, steps during school hours and cortisol. CONCLUSIONS: Implementing HIIT during curricular time improved adolescents' CRF and several secondary outcomes. Our findings suggest B2L is unlikely to be an effective approach unless teachers embed sessions within the school day. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry (ACTRN12618000293268).

Development and Evaluation of the High-Intensity Interval Training Self-Efficacy Questionnaire.

This study involved the design and evaluation of the High-Intensity Interval Training Self-Efficacy Questionnaire (HIIT-SQ). Phase 1: Questionnaire items were developed. Phase 2: Australian adolescents (N = 389, 16.0 ± 0.4 years, 41.10% female) completed the HIIT-SQ, and factorial validity of the measurement model was explored. Phase 3: Adolescents (N = 100, age 12-14 years, 44% female) completed the HIIT-SQ twice (1 week apart) to evaluate test-retest reliability. Confirmatory factor analysis of the final six items (mean = 3.43-6.73, SD = 0.99-25.30) revealed adequate fit, χ2(21) = 21, p = .01, comparative fit index = .99, Tucker-Lewis index = .99, root mean square of approximation = .07, 90% confidence interval [.04, .11]. Factor loading estimates showed that all items were highly related to the factor (estimates range: 0.81-0.90). Intraclass coefficients and typical error values were .99 (95% confidence interval [.99, 1.00]) and .22, respectively. This study provides preliminary evidence for the validity and reliability of scores derived from the HIIT-SQ in adolescents.

Sedentary behavior in everyday life relates negatively to mood: An ambulatory assessment study.

Empirical evidence shows that physical behavior positively impacts human health. Recently, researchers have started to differentiate between physical activity and sedentary behavior showing independent effects on somatic health. However, whether this differentiation is also relevant for mood dimensions is largely unknown. For investigating the dynamic relationships between sedentary behavior and mood dimensions in daily life, ambulatory assessment (AA) has become the state-of-the-art methodology. To investigate whether sedentary behaviors influence mood dimensions, we conducted an AA study in the everyday life of 92 university employees over 5 days. We continuously measured sedentary behavior via accelerometers and assessed mood repeatedly 10 times each day on smartphone diaries. To optimize our sampling strategy, we used a sophisticated sedentary-triggered algorithm. We employed multilevel modeling to analyze the within-subject effects of sedentary behavior on mood. Sedentary time (15-minute intervals prior to each e-diary assessment) and sedentary bouts (30-minute intervals of uninterrupted sedentary behavior) negatively influenced valence and energetic arousal (all Ps < 0.015). In particular, the more participants were sedentary in their everyday life, the less they felt well and energized. Exploratory analyses of the temporal course of these effects supported our findings. Sedentary behavior can be seen as a general risk factor because it impacts both somatic and mental health. Most importantly, physical activity and sedentary behavior showed independent effects on mood dimensions. Accordingly, future studies should consider the two sides of the physical behavior coin: How should physical activity be promoted? and How can sedentary behavior be reduced?

Mediating Effects of the 'eCoFit' Physical Activity Intervention for Adults at Risk of, or Diagnosed with, Type 2 Diabetes.

BACKGROUND: The study aim was to examine the mechanisms of physical activity behaviour change in the multi-component eCoFit randomised controlled trial (RCT) among adults diagnosed with, or at risk of, T2D. METHOD: The RCT included two phases: phase 1 (weeks 1-10) integrated group sessions (outdoor physical activity and cognitive mentoring) and the use of the eCoFit smartphone application (app), and phase 2 (weeks 11-20), which included the use of the eCoFit smartphone application only. Participants (n = 84) were assessed at baseline and 10 and 20 weeks from baseline. Physical activity was assessed using pedometers, and the following mediators were tested: action self-efficacy, barrier self-efficacy, recovery self-efficacy, implementation intentions, intention to have regular physical activity, outcome expectations, risk perception and implicit associations related to physical activity. The PROCESS INDIRECT Macro was used to perform mediation analyses. RESULTS: Significant mediation pathways were found for implementation intention measured at 10 weeks, AB (95% CI = 486.04 [128.19, 1073.42]). No significant pathways were found for the other social-cognitive and implicit attitudinal mediators. CONCLUSION: Increased daily steps among the intervention participants were explained by increased implementation intentions. The eCoFit study successfully operationalised implementation intentions in the smartphone app designed to promote outdoor physical activity. TRIAL REGISTRATION: The trial was approved by a University Human Research Committee and is registered with the Australian New Zealand Clinical Trial Registry (ACTRN12615000990527).

Feasibility and Preliminary Efficacy of a Teacher-Facilitated High-Intensity Interval Training Intervention for Older Adolescents.

PURPOSE: This study was designed to assess the feasibility and preliminary efficacy of a teacher-facilitated high-intensity interval training intervention for older adolescents (ie, 16-18 y). METHODS: Two secondary schools from New South Wales, Australia were recruited, and participants (ie, grade 11 students; 16.2 [0.4] y) were randomized at the school level to the Burn 2 Learn intervention (n = 38), or a wait-list control group (n = 30). Teachers were trained to facilitate the delivery of the novel high-intensity interval training program, which involved 3 sessions per week (∼12-20 min) for 14 weeks. A range of process measures were used to assess intervention feasibility (ie, recruitment, retention, attendance, and program satisfaction). Primary (cardiorespiratory fitness, determined using the progressive aerobic cardiovascular endurance run shuttle run test) and secondary outcomes were assessed at baseline and posttest (14-wk). RESULTS: Sixty-eight grade 11 students were recruited at baseline (85% of target sample), 61 participants completed posttest assessments (90% retention) and on average, participants performed 1.9 sessions per week. Overall, teachers (4.0/5) and students (4.0/5) were satisfied with the Burn 2 Learn program. Group by time effects were observed for cardiorespiratory fitness (8.9 laps; 95% confidence intervals, 1.7-16.2) and a selection of secondary outcomes. CONCLUSION: This study provides evidence for the feasibility and preliminary efficacy of a teacher-facilitated high-intensity interval training intervention for older adolescents.

Effectiveness of mother and daughter interventions targeting physical activity, fitness, nutrition and adiposity: A systematic review.

BACKGROUND: Physical inactivity and poor dietary habits in women pose a clear public health burden. Mothers are generally the main female role model for daughters, therefore, targeting intergenerational females simultaneously may be a novel approach. However, the effectiveness of this approach to improve physical activity, fitness, nutrition and adiposity has not been systematically examined. OBJECTIVES: To assess the effectiveness of physical activity, fitness and nutrition interventions targeting mothers and their daughters. DATA SOURCES: PubMed, Psychinfo, EMBASE, Ovid Medline, SCOPUS, CINAHL, Sportdiscus and Informit were searched for English language studies (1980-2015). STUDY SELECTION: Randomized controlled trials (RCTS), non-randomized experimental trials and pre-post studies of physical activity, fitness, nutrition and adiposity interventions targeting mothers and daughters were eligible if they reported changes in physical activity, fitness, dietary intake or adiposity. DATA EXTRACTION: Data were extracted using a standardized template and checked by a second author. DATA SYNTHESIS: 3577 articles were screened and 14 unique studies (7 RCTs, 1 pseudo-randomized, 1 non-randomized, 5 pre-post) met the inclusion criteria. The majority of studies were conducted in the US (n=11) and most were limited by methodological concerns. Of the RCTs that targeted each outcome exclusively, ≤20%, ≤20% ≤21% and 0% were successful for improving physical activity, fitness, nutrition and adiposity respectively. CONCLUSIONS: Overall, evidence for the effectiveness of mother-daughter interventions to improve physical activity, fitness, nutrition and adiposity is inconclusive. The diversity of study designs, exposures and outcomes used, along with methodological weaknesses means that well-designed and reported RCTs are warranted.

Exploring the impact of high intensity interval training on adolescents' objectively measured physical activity: Findings from a randomized controlled trial.

High Intensity Interval Training (HIIT) may be effective for accumulating VPA. However, the contribution of HIIT to overall physical activity is unknown. Our primary aim was to explore the impact of school-based HIIT on physical activity. The secondary aim was to explore within-individual changes in physical activity after participating in HIIT. Participants [n = 65; 15.8(0.6)years] were randomized to a HIIT or control group. Intervention groups participated in three HIIT sessions/week. GENEActiv accelerometers assessed objective physical activity at baseline and week-one, to detect changes in MPA and VPA. Intervention effects were examined using linear mixed models and evidence of a change in physical activity (i.e., compensation) were examined using multilevel linear regression models. The group-by-time interaction effects for MPA and VPA were small and moderate, respectively. Adjusted difference between groups for VPA was 1.70 min/day, 95%CI -1.96 to 5.36; p = 0.354; d = 0.55). Embedding HIIT within the school-day had a moderate effect on VPA compared to controls. Compensation analyses (i.e., individual level) suggested that adolescents were more active on days when they participated in HIIT. Further studies are needed to test the effects of HIIT on adolescents' physical activity over extended time periods.

Integrating smartphone technology, social support and the outdoor physical environment to improve fitness among adults at risk of, or diagnosed with, Type 2 Diabetes: Findings from the 'eCoFit' randomized controlled trial.

The risk and prevalence of Type 2 Diabetes (T2D) has dramatically increased over the past decade. The aim of this study was to develop, implement and evaluate a physical activity intervention to improve aerobic and muscular fitness among adults at risk of, or diagnosed with T2D. A 20-week, assessor blinded, parallel-group randomized controlled trial (RCT) was conducted at the University of Newcastle (June-December 2015). Adults were randomized to the intervention (n=42) or wait-list control group (n=42). The theory-based intervention included: Phase 1 (weeks 1-10) integrated group sessions (outdoor physical activity and cognitive mentoring), and the eCoFit smartphone application (app). Phase 2 (weeks 11-20) only included the eCoFit app. Participants were assessed at baseline, 10weeks and 20weeks. Linear mixed models (intention-to-treat) were used to determine group-by-time interactions at 10weeks (primary time-point) and 20weeks for the primary outcomes. Several secondary outcomes were also assessed. After 10weeks, significant group-by-time effects were observed for aerobic fitness (4.5mL/kg/min; 95% CI [1.3, 7.7], d=0.68) and muscular fitness (lower body) (3.4 reps, 95% CI [2.7, 4.2], d=1.45). Intervention effects for secondary outcomes included significant increased physical activity (1330steps/week), improved upper body muscular fitness (5 reps; arm-curl test), improved functionality (-1.8s; timed-up and go test) reduced waist circumference (2.8cm) and systolic blood pressure (-10.4mmHg). After 20weeks, significant effects were observed for lower body muscular fitness and health outcomes. eCoFit is an innovative lifestyle intervention which integrates smartphone technology, social support, and the outdoor environment to improve aerobic and muscular fitness.

Mediators of change in screen-time in a school-based intervention for adolescent boys: findings from the ATLAS cluster randomized controlled trial.

The mechanisms of behavior change in youth screen-time interventions are poorly understood. Participants were 361 adolescent boys (12-14 years) participating in the ATLAS obesity prevention trial, evaluated in 14 schools in low-income areas of New South Wales, Australia. Recreational screen-time was assessed at baseline, 8- and 18-months, whereas potential mediators (i.e., motivation to limit screen-time and parental rules) were assessed at baseline, 4- and 18-months. Multi-level mediation analyses followed the intention-to-treat principle and were conducted using a product-of-coefficients test. The intervention had a significant impact on screen-time at both time-points, and on autonomous motivation at 18-months. Changes in autonomous motivation partially mediated the effect on screen-time at 18-months in single and multi-mediator models [AB (95% CI) = -5.49 (-12.13, -.70)]. Enhancing autonomous motivation may be effective for limiting screen-time among adolescent males. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry No: ACTRN12612000978864.

Assessing the sustained impact of a school-based obesity prevention program for adolescent boys: the ATLAS cluster randomized controlled trial.

BACKGROUND: Obesity prevention interventions targeting 'at-risk' adolescents are urgently needed. The aim of this study is to evaluate the sustained impact of the 'Active Teen Leaders Avoiding Screen-time' (ATLAS) obesity prevention program. METHODS: Cluster RCT in 14 secondary schools in low-income communities of New South Wales, Australia. Participants were 361 adolescent boys (aged 12-14 years) 'at risk' of obesity. The intervention was based on Self-Determination Theory and Social Cognitive Theory and involved: professional development, fitness equipment for schools, teacher-delivered physical activity sessions, lunch-time activity sessions, researcher-led seminars, a smartphone application, and parental strategies. Assessments for the primary (body mass index [BMI], waist circumference) and secondary outcomes were conducted at baseline, 8- (post-intervention) and 18-months (follow-up). Analyses followed the intention-to-treat principle using linear mixed models. RESULTS: After 18-months, there were no intervention effects for BMI or waist circumference. Sustained effects were found for screen-time, resistance training skill competency, and motivational regulations for school sport. CONCLUSIONS: There were no clinically meaningful intervention effects for the adiposity outcomes. However, the intervention resulted in sustained effects for secondary outcomes. Interventions that more intensively target the home environment, as well as other socio-ecological determinants of obesity may be needed to prevent unhealthy weight gain in adolescents from low-income communities. TRIAL REGISTRATION: Australian Clinical Trial Registry ACTRN12612000978864.

Intervention to reduce recreational screen-time in adolescents: Outcomes and mediators from the 'Switch-Off 4 Healthy Minds' (S4HM) cluster randomized controlled trial.

INTRODUCTION: The primary objective was to evaluate the impact of the 'Switch-off 4 Healthy Minds' (S4HM) intervention on recreational screen-time in adolescents. METHODS: Cluster randomized controlled trial with study measures at baseline and 6-months (post-intervention). Eligible participants reported exceeding recreational screen-time recommendations (i.e., >2h/day). In total, 322 adolescents (mean age=14.4±0.6years) from eight secondary schools in New South Wales, Australia were recruited. The S4HM intervention was guided by Self-Determination Theory and included: an interactive seminar, eHealth messaging, a behavioral contract and parental newsletters. The primary outcome was recreational screen-time. Secondary outcomes included mental health (i.e., well-being, psychological distress, self-perceptions), objectively measured physical activity, and body mass index (BMI). Outcome analyses were conducted using linear mixed models and mediation was examined using a product-of-coefficients test. RESULTS: At post-intervention, significant reductions in screen-time were observed in both groups, with a greater reduction observed in the intervention group (-50min/day versus -29min, p<0.05 for both). However, the adjusted difference in change between groups was not statistically significant (mean=-21.3min/day, p=0.255). There were no significant intervention effects for mental health outcomes, physical activity or BMI. Significant mediation effects for autonomous motivation were found. CONCLUSIONS: Participants in both the S4HM intervention and control groups significantly reduced their screen-time, with no group-by-time effects. Enhancing autonomous motivation might be a useful intervention target for trials aimed at reducing adolescents' recreational screen-time. TRIAL REGISTRATION: ACTRN12614000163606.

Impact of a 3-year multi-centre community-based intervention on risk factors for chronic disease and obesity among free-living adults: the Healthy Alberta Communities study.

BACKGROUND: Healthy Alberta Communities (HAC) was a 3-year community-based intervention to reduce lifestyle-related risk factors for chronic disease and obesity at a population-level. The current paper examines changes in blood pressure (BP) and anthropometric indicators within HAC communities compared to secular trends. METHODS: Between 2006 and 2009, this community-academic partnership sought to create environments supportive of healthier dietary and physical activity behaviours within four diverse communities in Alberta, Canada. Height, weight, waist and hip circumference and BP were measured among 1554 and 1808 community residents at baseline (2006) and follow-up (2009), respectively. A comparison sample was drawn from a representative national survey. Samples were stratified by age and change between pre- and post-intervention was assessed using t-tests. Changes in parameters over time between groups were compared using meta-analysis. The net difference in change in outcomes (change in intervention communities minus change in comparison group) represented the effect of the intervention. RESULTS: Adjusted systolic (SBP) and diastolic (DBP) BP declined within most age groups in HAC communities from pre- to post-intervention. The net decline in SBP was 1 mmHg in 20-39 year olds (p = 0.006) and 2 mmHg in 40-59 year olds (p = 0.001), while the net decline in DBP was 3 mmHg in 20-39 year olds (p < 0.001), 2 mmHg in 40-59 year olds (p < 0.001) and 3 mmHg in 60-79 year olds (p < 0.001). The net increase in the proportion of individuals with normal BP was 5.9 % (p < 0.001), while the net decline in the proportion of individuals with stage 1 hypertension was 4.5 % (p < 0.001). BMI and body weight were unchanged. There was a significant net increase in waist and hip circumference among 20-39 year olds within intervention communities. CONCLUSIONS: Findings suggest HAC succeeded in shifting the population distribution of BP in a leftward direction. By contrast, anthropometric parameters remained unchanged or worsened within intervention communities. Therefore, while improvements in some clinical risk factors can be achieved through relatively diffuse and shorter-term community-level environmental changes, improvements in others may require interventions of greater intensity and duration. Evaluating the success of community-based interventions based on their efficacy in changing individual-level clinical indicators may, however, underestimate their potential.