Correlates of Physical Activity in 0- to 5-year-olds: A Systematic Umbrella Review and Consultation of International Researchers.

BACKGROUND: Many children aged 0-5 years do not meet the WHO physical activity guidelines. To develop effective, evidence-based interventions, it is necessary to understand which factors are associated with physical activity in early childhood. OBJECTIVE: To summarize the current evidence on correlates of physical activity in 0- to 5-year-old children. METHODS: First, a systematic umbrella review was conducted following PRISMA guidelines. PubMed, Embase, PsycINFO, and SPORTDiscus were searched up to May 2020 for systematic reviews examining the association between potential correlates and quantitatively measured physical activity in children aged 0-5.9 years. Included reviews were assessed on methodological quality, and results were categorized according to the socio-ecological model. Second, 31 international researchers of physical activity in young children participated in an expert panel to reflect on the outcomes of the umbrella review and propose directions for future research. RESULTS: Twenty-one reviews were included that examined a total of 98 potential correlates. When synthesizing all reviews, 23 correlates were found with consistent evidence for an association with a physical activity outcome. For most other potential correlates there was inconsistent evidence across reviews for associations with physical activity in young children. Although there was little overlap between the correlates identified in the umbrella review and determinants suggested by the expert panel, both confirmed the importance of socio-cultural, policy, and physical environmental factors in general. CONCLUSION: Multiple correlates of young children's physical activity were identified. However, various methodological challenges (e.g., measurement instruments) and the large heterogeneity (e.g., study samples, correlates, and outcome measures) hindered formulating definitive conclusions. Moreover, none of the reviews reported on the interrelatedness between correlates, which would align with more holistic understandings of behavior. Our findings indicate the urgent need for establishing a common ground in definitions, assessment methods, and analytical methods to further the field of physical activity research in this tremendously important age group. PROSPERO REGISTRATION NUMBER: CRD42020184159.

The Acute Effects of Standing on Executive Functioning in Vocational Education and Training Students: The Phit2Learn Study.

Research suggests that sedentary behavior (SB) is negatively associated with cognitive outcomes. Interrupting prolonged sitting has been shown to improve cognitive functions, including executive functioning (EF), which is important for academic performance. No research has been conducted on the effect of standing on EF in VET students, who make up a large proportion of the adolescent population and who are known to sit more than other students of this age. In this study, we investigated the acute effects of reducing SB by short time standing on EF in vocational education and training (VET) students. In a randomized crossover study, 165 VET students were first taught for 15 min in seated position. After this, they performed while seated the Letter Memory Test for updating, and the Color Shape Test for shifting and inhibition. Students were randomly assigned to a sitting or standing condition. All students were taught again for 15 min and then took the same tests in the condition they were allocated to, respectively, standing or seated. After 1 week, the test procedure was repeated, in which students switched conditions. Mixed model analyses showed no significant effect of sitting or standing on updating, shifting, or inhibition. Also, no significant differences were found for the order of condition on updating, shifting, or inhibition. Our results suggest that 40 min of standing does not significantly influence EF among VET students.

Differences in Habitual Physical Activity Behavior between Students from Different Vocational Education Tracks and the Association with Cognitive Performance.

Vocational education and training (VET) educates students for a broad range of occupations, which may be associated with differences in habitual physical activity behavior (PAB). Research suggests that physical activity (PA) is positively and sedentary behavior (SB) is negatively associated with cognitive performance. Therefore, we aimed to compare habitual PAB in VET students from different educational tracks and investigate its association with cognitive performance in a cross-sectional study. Students wore an ActivPAL accelerometer continuously for seven days to measure PAB. Cognitive performance was assessed with objective tests for inhibition, shifting, and updating. Hairdresser and Sports students sat significantly less than Administrative and Nursing students. Hairdresser students stood significantly more than other tracks. Admin students stood significantly less than Sports/Nursing students. Sports students moved significantly more than Hairdresser and Nursing students. Time in bed was significantly lowest in Nursing students. No significant associations between any PAB and cognitive performance were found. In general, Admin students showed the unhealthiest habitual PAB. Higher PA or lower SB neither improve nor decrease cognitive performance. Thus, future health interventions focusing on exchanging SB for PA at schools can facilitate a healthier lifestyle of VET students, especially in Admin students, without interfering with cognitive performance.

A Qualitative Study of the Feasibility and Acceptability of Implementing 'Sit-To-Stand' Desks in Vocational Education and Training.

While it has been shown that interrupting a person's sedentary behaviour has the potential to improve cognitive, physical and mental health, a large part of time that students spend in school is sedentary. As research has shown that approximately 80% of vocational education and training (VET) students have an unhealthy sedentary lifestyle, implementing "sit-to-stand" (StS) desks could interrupt sedentary behaviour and promote healthier behaviour. Therefore, the acceptability and feasibility of using such desks in the VET setting should be investigated. Using semi-structured focus group interviews analysed via deductive content analysis, the opinions of 33 students for the following topics were assessed: (1) usage of the standing option of the desks (2) reasons for standing in class (3) experienced effect of standing behind the desk, and (4) fostering future StS desks usage. Although VET students are aware of the potential benefits of using StS desks, they need to be actively stimulated and motivated by teachers to use them. In addition, time is needed to get into the habit of standing. Thus, for successful implementation of StS desks in the VET setting, all stakeholders (i.e., students, teachers, schoolboards) should be actively involved in stimulating the healthy behaviour of VET students.

Sleep characteristics across the lifespan in 1.1 million people from the Netherlands, United Kingdom and United States: a systematic review and meta-analysis.

We aimed to obtain reliable reference charts for sleep duration, estimate the prevalence of sleep complaints across the lifespan and identify risk indicators of poor sleep. Studies were identified through systematic literature search in Embase, Medline and Web of Science (9 August 2019) and through personal contacts. Eligible studies had to be published between 2000 and 2017 with data on sleep assessed with questionnaires including ≥100 participants from the general population. We assembled individual participant data from 200,358 people (aged 1-100 years, 55% female) from 36 studies from the Netherlands, 471,759 people (40-69 years, 55.5% female) from the United Kingdom and 409,617 people (≥18 years, 55.8% female) from the United States. One in four people slept less than age-specific recommendations, but only 5.8% slept outside of the 'acceptable' sleep duration. Among teenagers, 51.5% reported total sleep times (TST) of less than the recommended 8-10 h and 18% report daytime sleepiness. In adults (≥18 years), poor sleep quality (13.3%) and insomnia symptoms (9.6-19.4%) were more prevalent than short sleep duration (6.5% with TST < 6 h). Insomnia symptoms were most frequent in people spending ≥9 h in bed, whereas poor sleep quality was more frequent in those spending <6 h in bed. TST was similar across countries, but insomnia symptoms were 1.5-2.9 times higher in the United States. Women (≥41 years) reported sleeping shorter times or slightly less efficiently than men, whereas with actigraphy they were estimated to sleep longer and more efficiently than man. This study provides age- and sex-specific population reference charts for sleep duration and efficiency which can help guide personalized advice on sleep length and preventive practices.

The Effect of The Daily Mile on Primary School Children's Aerobic Fitness Levels After 12 Weeks: A Controlled Trial.

The Daily Mile (TDM) is a school-based physical activity intervention encompassing a 15-minute run at least three times per week. This study aimed to determine (1) the effects of performing TDM for 12 weeks on Dutch primary school children's aerobic fitness levels and (2) if additional personal support for teachers impacted the effectiveness of TDM. Nine Dutch primary schools (n = 659 children, grades 5-8) were allocated to a control (no TDM), intervention (12 weeks TDM) or intervention-plus (12 weeks TDM, additional personal support) group. The Shuttle Run Test (SRT) was used to assess aerobic fitness at baseline and follow-up. Data were analyzed using a multiple-imputed dataset and multilevel linear regression models to account for the clustering of students within classes and classes within schools. The regression analyses were adjusted for sex and age. Compared with the control group, significant intervention effects of TDM on SRT score were observed for the intervention group (ß = 1.1; 95% CI: 0.8; 1.5) and the intervention-plus group (ß = 0.6; 95% CI 0.3; 0.9). Additional personal support had no impact on the effectiveness of TDM. These results suggest that performing TDM at least three times per week for approximately 12 weeks increases primary school children's aerobic fitness. Additional personal support did not improve the effectiveness of TDM on aerobic fitness within this period. These results contribute to the body of evidence surrounding TDM, but further research is needed regarding long-term implementation of TDM.

Integrating Juggling with Math Lessons: A Randomized Controlled Trial Assessing Effects of Physically Active Learning on Maths Performance and Enjoyment in Primary School Children.

There are tentative indications that physical activity (PA) during school time can be beneficial for children's academic performance. So far, most studies have focused on the effects of moderate-to-vigorous PA, for example, in the form of energizers or extra physical education lessons. Little is known about the effects of physically active learning, in which PA is integrated with the academic content of the lessons, especially in preadolescent children. Moreover, there is a lack of knowledge regarding the enjoyment of physically active learning in this age group. Therefore, the aim of the current study was to assess the effects of integrating juggling with math practice in primary school children, on (1) multiplication memorization performance and (2) enjoyment during the math lessons. We conducted a cluster randomized controlled trial, in which 312 children (mean age 10.4 years) from nine Dutch primary schools participated. Fourteen classes were randomly assigned to either a group that learned juggling whilst practicing multiplication tables (intervention group), or to a group that practiced the same multiplication tables while sedentary (control group). Both interventions had a duration of 5 weeks and consisted of 20 short lessons (4 lessons per week, 5 to 8 min). We used mixed-model analyses to examine the effect of the intervention on multiplication memorization performance. Group (control or intervention) was used as the fixed factor, and class and school as random intercepts. Analyses were adjusted for pretest multiplication performance, age, gender, general motor skill level, physical activity behavior (PAQ-C), and academic math performance. No significant intervention effect on multiplication performance were observed. However, the math-juggling program significantly increased enjoyment of children during the math lessons. We can conclude that the intervention did not improve, but neither deteriorated children's math performance. The increased enjoyment in the math-juggling group can serve as an important starting point for structurally incorporating physical activities in the classroom setting.

Improving Cognitive Performance of 9-12 Years Old Children: Just Dance? A Randomized Controlled Trial.

Exercise is assumed to have positive effects on children's cognitive performance. However, given the inconclusive evidence for the long-term effects of exercise, it is difficult to advice schools on what specific exercise programs can improve children's cognitive performance. In particular, little is known about the effects of small exercise programs that may be feasible in daily school practice. Therefore, we assessed the effects of a 9-weeks program consisting of daily exercise breaks on children's cognitive performance, aerobic fitness and physical activity levels. We conducted a cluster-randomized controlled trial in 21 classes of eight Dutch primary schools. A total of 512 children aged 9-12 years participated. The exercise intervention had a duration of 9 weeks and consisted of a daily 10-min classroom-based exercise break of moderate to vigorous intensity. Before and after the intervention, we used four cognitive tasks (i.e., the Attention Network Test, Stroop test, d2 test of attention and Fluency task) to measure children's cognitive performance in domains of selective attention, inhibition and memory retrieval. In addition, we measured aerobic fitness with a Shuttle Run test and physical activity during school hours by accelerometers. We analyzed data using mixed models, adjusting for baseline scores, class and school. After 9 weeks, there were no intervention effects on children's cognitive performance or aerobic fitness. Children in the intervention group spent 2.9 min more of their school hours in moderate to vigorous physical activity as compared to the children in the control group. In conclusion, daily 10-min exercise breaks in the classroom did not improve, nor deteriorate cognitive performance in children. The exercise breaks had no effect on children's fitness, and resulted in 2.9 min more time spent in moderate to vigorous physical activity during school hours. Daily exercise breaks can be implemented in the classroom to promote children's physical activity during school time, without adverse effect on their cognitive performance.

Effects of physical activity interventions on cognitive and academic performance in children and adolescents: a novel combination of a systematic review and recommendations from an expert panel.

OBJECTIVE: To summarise the current evidence on the effects of physical activity (PA) interventions on cognitive and academic performance in children, and formulate research priorities and recommendations. DESIGN: Systematic review (following PRISMA guidelines) with a methodological quality assessment and an international expert panel. We based the evaluation of the consistency of the scientific evidence on the findings reported in studies rated as of high methodological quality. DATA SOURCES: PubMed, PsycINFO, Cochrane Central, Web of Science, ERIC, and SPORTDiscus. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: PA-intervention studies in children with at least one cognitive or academic performance assessment. RESULTS: Eleven (19%) of 58 included intervention studies received a high-quality rating for methodological quality: four assessed effects of PA interventions on cognitive performance, six assessed effects on academic performance, and one on both. All high-quality studies contrasted the effects of additional/adapted PA activities with regular curriculum activities. For cognitive performance 10 of 21 (48%) constructs analysed showed statistically significant beneficial intervention effects of PA, while for academic performance, 15 of 25 (60%) analyses found a significant beneficial effect of PA. Across all five studies assessing PA effects on mathematics, beneficial effects were reported in six out of seven (86%) outcomes. Experts put forward 46 research questions. The most pressing research priority cluster concerned the causality of the relationship between PA and cognitive/academic performance. The remaining clusters pertained to PA characteristics, moderators and mechanisms governing the 'PA-performance' relationship and miscellaneous topics. CONCLUSION: There is currently inconclusive evidence for the beneficial effects of PA interventions on cognitive and overall academic performance in children. We conclude that there is strong evidence for beneficial effects of PA on maths performance.The expert panel confirmed that more 'high-quality' research is warranted. By prioritising the most important research questions and formulating recommendations we aim to guide researchers in generating high-quality evidence. Our recommendations focus on adequate control groups and sample size, the use of valid and reliable measurement instruments for physical activity and cognitive performance, measurement of compliance and data analysis. PROSPERO REGISTRATION NUMBER: CRD42017082505.

Untapped Resources: 10- to 13-Year-Old Primary Schoolchildren's Views on Additional Physical Activity in the School Setting: A Focus Group Study.

Schools are considered ideal venues to promote physical activity (PA) in children. However, a knowledge gap exists on how to adequately integrate PA into the school day and in particular, on the preferences of children regarding additional PA in school. Therefore, the aim of our qualitative study was to gain comprehensive insight into 10⁻13-year-old primary schoolchildren's perspectives on how to increase PA in the school setting. We conducted nine focus groups (32 girls and 20 boys) with children attending the final two grades of primary school in the Netherlands. We used inductive thematic analysis to analyze the data. The results showed that children were enthusiastic about additional PA in school. Children suggested various ways to increase PA, including more time for PA in the existing curriculum, e.g., physical education (PE), recess, and occasional activities, such as field trips or sports days; school playground adaptation; improving the content of PE; and implementing short PA breaks and physically active academic lessons. Children emphasized variation and being given a voice in their PA participation as a prerequisite to keep PA enjoyable and interesting in the long term. Finally, children mentioned the role of the teacher and making efforts to accommodate all children and their different preferences as important. Children have concrete ideas, acknowledging the challenges that accompany integrating additional PA in school. We therefore recommend actively involving children in efforts to increase school-based PA and to make "additional PA in school" a shared project of teachers and students.

Exercise of Varying Durations: No Acute Effects on Cognitive Performance in Adolescents.

Participation in structured physical activity is assumed to have a positive effect on cognitive and academic performance. A single bout of moderate to vigorous exercise has been found to have a small acute positive effect on the cognitive performance of children and adolescents. However, the dose-response effects of exercise duration are largely unknown. Therefore, the current study examined the acute effects of moderate-to-vigorous exercise with a duration of either 10, 20, or 30 min on selective attention and working memory performance of young adolescents. One hundred and nineteen adolescents (11-14 years old) participated in a randomized, controlled crossover study. Adolescents were assigned to one of the three exercise durations, each paired with a sedentary control session of the same duration. Cognitive performance was measured before and immediately after the exercise and control condition. The Attention Network Test and n-back task were used to measure selective attention and working memory, respectively. There were no significant exercise effects on selective attention (i.e., alerting, orienting, or executive control) or working memory performance measured immediately after the exercise bouts. Furthermore, there were no differential effects of exercise duration. In sum, acute exercise bouts with a duration of 10, 20, or 30 min did not improve, but neither deteriorate cognitive performance of young adolescents compared to a sedentary control condition.

"It's a Battle You Want to Do It, but How Will You Get It Done?": Teachers' and Principals' Perceptions of Implementing Additional Physical activity in School for Academic Performance.

School is an ideal setting to promote and increase physical activity (PA) in children. However, implementation of school-based PA programmes seems difficult, in particular due to schools' focus on academic performance and a lack of involvement of school staff in program development. The potential cognitive and academic benefits of PA might increase chances of successful implementation. Therefore, the aim of this qualitative study was: (1) to explore the perceptions of teachers and principals with regard to implementation of additional PA aimed at improving cognitive and academic performance, and (2) to identify characteristics of PA programmes that according to them are feasible in daily school practice. Twenty-six face-to-face semi-structured interviews were conducted with primary school teachers (grades 5 and 6) and principals in The Netherlands, and analysed using inductive content analysis. Teachers and principals expressed their willingness to implement additional PA if it benefits learning. Time constraints appeared to be a major barrier, and strongly influenced participants' perceptions of feasible PA programmes. Teachers and principals emphasised that additional PA needs to be short, executed in the classroom, and provided in "ready-to-use" materials, i.e., that require no or little preparation time (e.g., a movie clip). Future research is needed to strengthen the evidence on the effects of PA for academic purposes, and should examine the forms of PA that are both effective as well as feasible in the school setting.

Physical Activity in the School Setting: Cognitive Performance Is Not Affected by Three Different Types of Acute Exercise.

Recent studies indicate that a single bout of physical exercise can have immediate positive effects on cognitive performance of children and adolescents. However, the type of exercise that affects cognitive performance the most in young adolescents is not fully understood. Therefore, this controlled study examined the acute effects of three types of 12-min classroom-based exercise sessions on information processing speed and selective attention. The three conditions consisted of aerobic, coordination, and strength exercises, respectively. In particular, this study focused on the feasibility and efficiency of introducing short bouts of exercise in the classroom. One hundred and ninety five students (5th and 6th grade; 10-13 years old) participated in a double baseline within-subjects design, with students acting as their own control. Exercise type was randomly assigned to each class and acted as between-subject factor. Before and immediately after both the control and the exercise session, students performed two cognitive tests that measured information processing speed (Letter Digit Substitution Test) and selective attention (d2 Test of Attention). The results revealed that exercising at low to moderate intensity does not have an effect on the cognitive parameters tested in young adolescents. Furthermore, there were no differential effects of exercise type. The results of this study are discussed in terms of the caution which should be taken when conducting exercise sessions in a classroom setting aimed at improving cognitive performance.

Implemented or not implemented? Process evaluation of the school-based obesity prevention program DOiT and associations with program effectiveness.

This study investigates if and to what extent the Dutch Obesity Intervention in Teenagers (DOiT) program was implemented as intended and how this affected program effectiveness. We collected data at 20 prevocational education schools in the Netherlands. We assessed seven process indicators: recruitment, reach, dosage, fidelity, satisfaction, effectiveness and continuation. Data collection involved teacher questionnaires (n= 110), adolescent questionnaires and adiposity measures (n= 938). Using multi-level confirmatory factor analyses, we applied an innovative method to obtain explorative implementation index scores. The percentage of accomplished activities ranged from 9% (for 'closure meeting') up to 93% (for 'obtaining support within the school for adoption'). The percentage of lessons delivered decreased from 74 to 18% towards the end of the program. Fidelity to the teacher manual ranged from 85 to 26%. In general, teachers were satisfied with the DOiT lessons and teaching materials. Despite teachers' satisfaction with the DOiT lessons and teaching materials, degree of program implementation was lower than expected, especially towards the end of the program. Further, some evidence was found for an association between a higher implementation index score and program effectiveness, but more research is needed to test the validity of the implementation index.

Barriers and facilitators to the nationwide dissemination of the Dutch school-based obesity prevention programme DOiT.

BACKGROUND: This article describes the barriers and facilitating factors to the adoption, implementation and continuation of the Dutch Obesity Intervention in Teenagers (DOiT) programme in the Netherlands. METHODS: We evaluated the adoption, implementation and continuation of the programme at 20 voluntary prevocational schools, which adopted the programme. Interviews were conducted with DOiT coordinators and/or teachers (n = 44) at the end of the first and second school year of the 2-year implementation period. Interviews were recorded and transcribed verbatim. Data were coded by two researchers independently. Identified barriers and facilitating factors were categorized into four groups: (i) organizational factors, (ii) individual factors, (iii) characteristics of the programme and (iv) characteristics of the implementation strategy. RESULTS: Teachers and DOiT coordinators identified various implementation barriers (e.g. lack of planning, other urgent unforeseen priorities, no plan to cope with teacher turnover and high teacher workload) as well as facilitating factors (e.g. involvement of DOiT coordinator and support from the DOiT office, sufficient communication and collaboration between teachers, strong teacher motivation and flexibility of the programme). CONCLUSION: Overall, DOiT implementers were satisfied with the compatibility, layout, content and potential for tailoring the programme. Barriers for successful implementation were mainly at the school and teacher level. Findings of this study can be used for further improvement of the DOiT programme and for the development and improvement of other health promotion programmes in the school setting.

Effects of one versus two bouts of moderate intensity physical activity on selective attention during a school morning in Dutch primary schoolchildren: A randomized controlled trial.

OBJECTIVES: Evidence suggests that physical activity is positively related to several aspects of cognitive functioning in children, among which is selective attention. To date, no information is available on the optimal frequency of physical activity on cognitive functioning in children. The current study examined the acute effects of one and two bouts of moderate-intensity physical activity on children's selective attention. DESIGN: Randomized controlled trial (ISRCTN97975679). METHODS: Thirty boys and twenty-six girls, aged 10-13 years, were randomly assigned to three conditions: (A) sitting all morning working on simulated school tasks; (B) one 20-min physical activity bout after 90min; and (C) two 20-min physical activity bouts, i.e. at the start and after 90min. Selective attention was assessed at five time points during the morning (i.e. at baseline and after 20, 110, 130 and 220min), using the 'Sky Search' subtest of the 'Test of Selective Attention in Children'. We used GEE analysis to examine differences in Sky Search scores between the three experimental conditions, adjusting for school, baseline scores, self-reported screen time and time spent in sports. RESULTS: Children who performed two 20-min bouts of moderate-intensity physical activity had significantly better Sky Search scores compared to children who performed one physical activity bout or remained seated the whole morning (B=-0.26; 95% CI=[-0.52; -0.00]). CONCLUSIONS: Our findings support the importance of repeated physical activity during the school day for beneficial effects on selective attention in children.

A process evaluation of implementing a vocational enablement protocol for employees with hearing difficulties in clinical practice.

OBJECTIVE: A multidisciplinary vocational rehabilitation programme, the Vocational Enablement Protocol (VEP) was developed to address the specific needs of employees with hearing difficulties. In the current study we evaluated the process of implementing the VEP in audiologic care among employees with hearing impairment. DESIGN: In conjunction with a randomized controlled trial, we collected and analysed data on seven process parameters: recruitment, reach, fidelity, dose delivered, dose received and implemented, satisfaction, and perceived benefit. STUDY SAMPLE: Sixty-six employees with hearing impairment participated in the VEP. The multidisciplinary team providing the VEP comprised six professionals. RESULTS: The professionals performed the VEP according to the protocol. Of the recommendations delivered by the professionals, 31% were perceived as implemented by the employees. Compliance rate was highest for hearing-aid uptake (51%). Both employees and professionals were highly satisfied with the VEP. Participants rated good perceived benefit from it. CONCLUSIONS: Our results indicate that the VEP could be a useful treatment for employees with hearing difficulties from a process evaluation perspective. Implementation research in the audiological setting should be encouraged in order to further provide insight into parameters facilitating or hindering successful implementation of an intervention and to improve its quality and efficacy.

Determinants of physical activity in a cohort of young adult women. Who is at risk of inactive behaviour?

OBJECTIVES: To identify the biological, socio-demographic, work-related and lifestyle determinants of physical activity in young adult women. DESIGN: Prospective cohort study. METHODS: Self-reported data from 11,695 participants (aged 22-27 years in 2000) in the Australian Longitudinal Study on Women's Health were collected over 9 years in 2000, 2003, 2006 and 2009. Generalised Estimating Equations were used to examine univariable and multivariable associations of body mass index, country of birth, area of residence, education, marital status, number of children, occupational status, working hours, smoking, alcohol intake, and stress with physical activity status (active, ≥600 MET·min/week; or inactive, <600 MET·min/week, consistent with public health guidelines). RESULTS: All variables were significantly associated with physical activity in univariable models. In the multivariable model, the lowest odds of being active (compared with the relevant reference categories) were for women who: were born in Asia (OR=0.53), had less than 12 years of education (OR=0.79), were married (OR=0.66) or in a de facto relationship (OR=0.79), had at least one child (OR ranging from 0.67 to 0.69), and were classified as non (OR=0.66) or rare drinkers (OR=0.79). CONCLUSIONS: These results are among the first to confirm the biological, socio-demographic, work-related and lifestyle determinants of physical activity in women in their twenties and early thirties. These findings may be used to inform and improve the development of strategies, and to identify target groups most in need of intervention effort.

The Dutch Obesity Intervention in Teenagers (DOiT) cluster controlled implementation trial: intervention effects and mediators and moderators of adiposity and energy balance-related behaviours.

BACKGROUND: The Dutch Obesity Intervention in Teenagers (DOiT) programme is an evidence-based obesity prevention programme tailored to adolescents attending the first two years of prevocational education in the Netherlands. The initial programme showed promising results during an effectiveness trial. The programme was adapted and prepared for nationwide dissemination. To gain more insight into the process of translating evidence-based approaches into 'real world' (i.e., 'natural') conditions, our research aims were to evaluate the impact of the DOiT-implementation programme on adolescents' adiposity and energy balance-related behaviours during natural dissemination and to explore the mediating and moderating factors underlying the DOiT intervention effects. METHODS: We conducted a cluster-controlled implementation trial with 20 voluntary intervention schools (n=1002 adolescents) and 9 comparable control schools (n = 484 adolescents). We measured adolescents' body height and weight, skinfold thicknesses, and waist circumference. We assessed adolescents' dietary and physical activity behaviours by means of self-report. Data were collected at baseline and at 20-months follow-up. We used multivariable multilevel linear or logistic regression analyses to evaluate the intervention effects and to test the hypothesised behavioural mediating factors. We checked for potential effect modification by gender, ethnicity and education level. RESULTS: We found no significant intervention effects on any of the adiposity measures or behavioural outcomes. Furthermore, we found no mediating effects by any of the hypothesised behavioural mediators. Stratified analyses for gender showed that the intervention was effective in reducing sugar-containing beverage consumption in girls (B = -188.2 ml/day; 95% CI = -344.0; -32.3). In boys, we found a significant positive intervention effect on breakfast frequency (B = 0.29 days/week; 95% CI = 0.01; 0.58). Stratified analyses for education level showed an adverse intervention effect (B = 0.09; 95% CI = 0.02; 0.16) on BMI z-scores for adolescents attending the vocational education track. CONCLUSIONS: Although not successful in changing adolescents' adiposity, the DOiT-implementation programme had some beneficial effects on specific obesity-related behaviours in subgroups. This study underlines the difficulty of translating intervention effectiveness in controlled settings to real world contexts. Adaptations to the implementation strategy are needed in order to promote implementation as intended by the teachers. TRIAL REGISTRATION: Current Controlled Trials ISRCTN92755979.