A system dynamics approach to understand Dutch adolescents' sleep health using a causal loop diagram.

BACKGROUND: Healthy sleep is crucial for the physical and mental wellbeing of adolescents. However, many adolescents suffer from poor sleep health. Little is known about how to effectively improve adolescent sleep health as it is shaped by a complex adaptive system of many interacting factors. This study aims to provide insights into the system dynamics underlying adolescent sleep health and to identify impactful leverage points for sleep health promotion interventions. METHODS: Three rounds of single-actor workshops, applying Group Model Building techniques, were held with adolescents (n = 23, 12-15 years), parents (n = 14) and relevant professionals (n = 26). The workshops resulted in a multi-actor Causal Loop Diagram (CLD) visualizing the system dynamics underlying adolescent sleep health. This CLD was supplemented with evidence from the literature. Subsystems, feedback loops and underlying causal mechanisms were identified to understand overarching system dynamics. Potential leverage points for action were identified applying the Action Scales Model (ASM). RESULTS: The resulting CLD comprised six subsystems around the following themes: (1) School environment; (2) Mental wellbeing; (3) Digital environment; (4) Family & Home environment; (5) Health behaviors & Leisure activities; (6) Personal system. Within and between these subsystems, 16 reinforcing and 7 balancing feedback loops were identified. Approximately 60 potential leverage points on different levels of the system were identified as well. CONCLUSIONS: The multi-actor CLD and identified system dynamics illustrate the complexity of adolescent sleep health and supports the need for developing a coherent package of activities targeting different leverage points at all system levels to induce system change.

Do financial constraint and perceived stress modify the effects of food tax schemes on food purchases: moderation analyses in a virtual supermarket experiment.

OBJECTIVE: To investigate whether financial constraint and perceived stress modify the effects of food-related taxes on the healthiness of food purchases. DESIGN: Moderation analyses were conducted with data from a trial where participants were randomly exposed to: a control condition with regular food prices, an sugar-sweetened beverage (SSB) tax condition with a two-tiered levy on the sugar content in SSB (5-8 g/100 ml: €0·21 per l and ≥8 g/100 ml: €0·28 per l) or a nutrient profiling tax condition where products with Nutri-Score D or E were taxed at a 20 percent level. Outcome measures were overall healthiness of food purchases (%), energy content (kcal) and SSB purchases (litres). Effect modification was analysed by adding interaction terms between conditions and self-reported financial constraint or perceived stress in regression models. Outcomes for each combination of condition and level of effect modifier were visualised. SETTING: Virtual supermarket. PARTICIPANTS: Dutch adults (n 386). RESULTS: Financial constraint or perceived stress did not significantly modify the effects of food-related taxes on the outcomes. Descriptive analyses suggest that in the control condition, the overall healthiness of food purchases was lowest, and SSB purchases were highest among those with moderate/high levels of financial constraint. Compared with the control condition, in a nutrient profiling tax condition, the overall healthiness of food purchases was higher and SSB purchases were lower, especially among those with moderate/high levels of financial constraint. Such patterns were not observed for perceived stress. CONCLUSION: Further studies with larger samples are recommended to assess whether food-related taxes differentially affect food purchases of subgroups.

Adolescent sleep duration: associations with social-cognitive determinants and the mediating role of sleep hygiene practices.

Insufficient sleep duration among adolescents is a widespread public health problem. Gaining better insight into social-cognitive determinants associated with adolescent sleep duration is necessary for developing effective preventive interventions to support healthy sleep. This study aimed to explore whether social-cognitive determinants regarding sufficient sleep duration were associated with sleep duration, and if these associations were mediated by collective sleep hygiene practices. Furthermore, we examined these associations for social-cognitive determinants related to not using media before bedtime and doing relaxing activities and considered whether these associations were mediated by specific sleep hygiene practices. Data were collected amongst second- and third-grade adolescents from 10 Dutch high schools. A total of 878 adolescents (mean [SD] age 13.3 [0.71] years) completed data on sleep duration, social-cognitive determinants of the Theory of Planned Behaviour (i.e., attitude, subjective norms from parents, subjective norms from peers, perceived behavioural control, intention), and sleep hygiene practices. Single- and multivariable path models were constructed and mediation by sleep hygiene practices was analysed by Monte Carlo simulation. All social-cognitive determinants except for subjective norms from peers were associated with longer sleep duration (p < 0.01). Sleep hygiene practices mediated all associations between social-cognitive determinants and sleep duration (mediation ranging from 16% to 72%). Although some of the significant associations and mediation disappeared in the multivariable model, behavioural arousal was the strongest mediator, but collective sleep hygiene practices and cognitive/emotional arousal also explained parts of the associations. The findings indicate that social-cognitive factors should not be overlooked when targeting adolescent sleep duration.

Social Environmental Predictors of Lapse in Dietary Behavior: An Ecological Momentary Assessment Study Amongst Dutch Adults Trying to Lose Weight.

BACKGROUND: When losing weight, most individuals find it difficult to maintain a healthy diet. Social environmental conditions are of pivotal importance in determining dietary behavior. To prevent individuals from lapsing, insight in social environmental predictors of lapse in dietary behavior is needed. PURPOSE: Identify social environmental predictors of lapse in dietary behavior, using ecological momentary assessment (EMA) amongst Dutch adults trying to lose weight. METHODS: Adults (N = 81) participated in two 7-day EMA weeks. Six times a day semi-random prompts were sent. At each prompt, participants indicated whether a lapse had occurred and responded to questions assessing social support, descriptive norm, injunctive norm, social pressure, presence of others, and current location. Generalized estimating equations were used to examine associations with lapse. RESULTS: Injunctive norm (OR = 1.07, 95% CI = 1.03-1.11), descriptive norm (OR = 1.04, 95% CI = 1.02-1.07), and social pressure (OR = 1.09, 95% CI = 1.05-1.14), all toward diverting from diet plans, predicted lapses. Social support toward sticking to diet plans and presence of others did not predict lapses. When controlling for a prior lapse, all other associations became nonsignificant. Lapses occurred most often at home and gradually occurred more often during the day. CONCLUSIONS: Traditional public health perspectives have mainly focused on individual choice and responsibility for overweight related unhealthy lifestyles. This study shows that there may be opportunities to enhance intervention programs by also focusing on social norms and social pressure. The involvement of partners or housemates may create more awareness of the impact of (unintentional) social pressure on risk of lapsing, and reduce the level of exerted social pressure.

When losing weight, most individuals find it difficult to maintain a healthy diet. As social environmental conditions are of pivotal importance in determining dietary behavior, insight in social environmental predictors of lapse in dietary behavior is needed to prevent individuals from lapsing. Therefore, this study identified social environmental predictors of lapse in dietary behavior, using ecological momentary assessment (EMA) amongst Dutch adults trying to lose weight. A total of 81 participants took part in two 7-day EMA weeks, in which six times a day semi-random prompts were sent. At each prompt, participants indicated whether a lapse had occurred and responded to questions assessing social support, descriptive norm, injunctive norm, social pressure, presence of others, and current location. The results show that injunctive norm, descriptive norm, and social pressure, all toward diverting from diet plans, predicted dietary lapses. Social support toward sticking to diet plans and presence of others did not predict dietary lapses. Additionally, lapses occurred most often at home and gradually occurred more often during the day. This study shows that there may be opportunities to enhance intervention programs by also focusing on social norms and social pressure.

Correlates of inadequate sleep health among primary school children.

The aim of the present study was to explore potential factors of inadequate sleep health (i.e. sleep duration, quality, and timing) of school-aged children. Data were collected among 382 primary school children (aged 4-13 years) and their parents. Personal characteristics (i.e. age, sex), individual lifestyle behaviours (i.e. screen use, sleep hygiene behaviour), social and community factors (i.e. parental sleep-related practices, parental barriers, perceived ethnicity), and living conditions (i.e. parental educational level, sleep environment) were assessed with a parental questionnaire. Sleep duration, quality, and timing were assessed with a sleep diary. Associations were analysed using linear mixed models and logistic regression analyses. In total, 332 children, with a mean (range) age of 7.5 (4-13) years, were included in the analyses. The mean sleep duration was 632 min/night, the mean sleep quality score was 40, on a scale from 10 to 50, and 25% had a bedtime that varied >40 min between weekdays. Factors negatively associated with children's sleep health included older age, perceived non-Dutch cultural background, lower parental pre-sleep emotional support, the parental barrier to get their child to bed on time when siblings have a later bedtime, high parental educational level, sleeping in a darkened bedroom, and being brought to bed after falling asleep. On average, children in the present study had adequate sleep health. The factors found to be associated with children's sleep health are useful for future healthy sleep research and intervention development.

The effects of a sugar-sweetened beverage tax and a nutrient profiling tax based on Nutri-Score on consumer food purchases in a virtual supermarket: a randomised controlled trial.

OBJECTIVE: To investigate the effects of a sugar-sweetened beverage (SSB) tax and a nutrient profiling tax on consumer food purchases in a virtual supermarket. DESIGN: A randomised controlled trial was conducted with a control condition with regular food prices (n 152), an SSB tax condition (n 130) and a nutrient profiling tax condition based on Nutri-Score (n 112). Participants completed a weekly grocery shop for their household. Primary outcome measures were SSB purchases (ordinal variable) and the overall healthiness of the total shopping basket (proportion of total unit food items classified as healthy). The secondary outcome measure was the energy (kcal) content of the total shopping basket. Data were analysed using regression analyses. SETTING: Three-dimensional virtual supermarket. PARTICIPANTS: Dutch adults aged ≥18 years are being responsible for grocery shopping in their household (n 394). RESULTS: The SSB tax (OR = 1·62, (95 % CI 1·03, 2·54)) and the nutrient profiling tax (OR = 1·88, (95 %CI 1·17, 3·02)) increased the likelihood of being in a lower-level category of SSB purchases. The overall healthiness of the total shopping basket was higher (+2·7 percent point, (95 % CI 0·1, 5·3)), and the energy content was lower (-3301 kcal, (95 % CI -6425, -177)) for participants in the nutrient profiling tax condition than for those in the control condition. The SSB tax did not affect the overall healthiness and energy content of the total shopping basket (P > 0·05). CONCLUSIONS: A nutrient profiling tax targeting a wide range of foods and beverages with a low nutritional quality seems to have larger beneficial effects on consumer food purchases than taxation of SSB alone.

Stakeholder views on taxation of sugar-sweetened beverages and its adoption in the Netherlands.

An increasing number of governments worldwide have introduced a tax on sugar-sweetened beverages (SSB) for public health. However, the adoption of such a policy is still debated in many other countries, such as in the Netherlands. We investigated Dutch stakeholder views on taxation of SSB and perceived barriers and facilitators to its adoption in the Netherlands. Semi-structured interviews were conducted in 2019 with 27 stakeholders from health and consumer organizations, health professional associations, trade associations, academia, advisory bodies, ministries and parliamentary parties. Data were analysed using a thematic content approach. The findings reveal that, between and within sectors, stakeholders expressed contradictory views on the effectiveness, appropriateness and (socio)economic effects of an SSB tax. Perceived barriers to the adoption of an SSB tax in the Netherlands included an unfavourable political context, limited advocacy for an SSB tax, a strong lobby against an SSB tax, perceived public opposition, administrative load and difficulties in defining SSB. Perceived facilitators to its adoption included an increasing prevalence of overweight, disappointing results from voluntary industry actions, a change of government, state budget deficits, a shift in public opinion, international recommendations and a solid legal basis. In conclusion, this study shows that several challenges remain to be overcome for the adoption of an SSB tax in the Netherlands. Similar research on stakeholder views in other countries may further inform SSB tax policy processes.

Public acceptability of a sugar-sweetened beverage tax and its associated factors in the Netherlands.

OBJECTIVE: To investigate the level of public acceptability of a sugar-sweetened beverage (SSB) tax and its associated factors. DESIGN: Participants completed an online self-administered questionnaire. Acceptability of an SSB tax was measured on a seven-point Likert scale (strongly disagree to strongly agree). Associations between acceptability and sociodemographic factors, weight status, SSB consumption and beliefs about effectiveness (e.g., 'An SSB tax would reduce people's SSB consumption'), appropriateness, socioeconomic and economic benefit, implementation and trust were assessed using multivariable linear regression analyses. SETTING: The Netherlands. PARTICIPANTS: Dutch adults aged ≥18 years representative of the Dutch population for age, sex, education level and location (n 500). RESULTS: Of the participants, 40 % supported and 43 % opposed an SSB tax in general. Moreover, 42 % supported (43 % opposed) an SSB tax as a strategy to reduce overweight, and 55 % supported (32 % opposed) an SSB tax if revenue is used for health initiatives. Participants with a low education level (B = -0·82, 95 % CI -1·31, -0·32), overweight (B = -0·49, 95 % CI -0·89, -0·09), moderate or high SSB consumption (B = -0·86, 95 % CI -1·30, -0·43 and B = -1·01, 95 % CI -1·47, -0·56, respectively) and households with adolescents (B = -0·57, 95 % CI -1·09, -0·05) reported a lower acceptability of an SSB tax than their counterparts. Beliefs about effectiveness, appropriateness, socioeconomic and economic benefit, implementation and trust were associated with acceptability (P < 0·001). CONCLUSIONS: Public acceptability of an SSB tax tends to be higher if revenue is used for health initiatives. The factors associated with acceptability should be taken into consideration.

Predictors of Changes in Sleep Duration in Dutch Primary Schoolchildren: the ChecKid Study.

BACKGROUND: Healthy sleep duration is essential to health and well-being in childhood and later life. Unfortunately, recent evidence shows a decline in sleep duration among children. Although effective interventions promoting healthy sleep duration require insight into its predictors, data on these factors are scarce. This study therefore investigated (i) which individual (lifestyle), social and cultural factors, and living conditions and (ii) which changes in these factors might be associated with the changes in sleep duration of Dutch primary schoolchildren observed over time. METHOD: Data from the ChecKid study was used, a dynamic cohort study among 4-13-year-old children living in the city of Zwolle, the Netherlands. Associations between changes in sleep duration and individual (lifestyle) factors (i.e., age, sex, physical activity behavior, sugar-sweetened beverage consumption, screen behavior), social and cultural factors (i.e., parental rules, ethnicity), and living conditions (i.e., parental education, presence of screens in the bedroom, household size) were analyzed using multivariable linear regression. RESULTS: A total of 1180 children participated, aged 6.6 ± 1.4 years in 2009. Mean sleep duration decreased from 11.4 ± 0.5 h/night in 2009 to 11.0 ± 0.5 h/night in 2012. Older children, boys, children who used screens after dinner, children with greater computer/game console use, and children whose parents had low levels of education had a greater decrease in sleep duration. CONCLUSIONS: This article reports on one of the first large, longitudinal cohort studies on predictors of child sleep duration. The results of the study can inform future interventions aimed at promoting healthy sleep in primary schoolchildren.

The Effect of Postural Pelvic Dynamics on the Three-dimensional Orientation of the Acetabular Cup in THA Is Patient Specific.

BACKGROUND: Sagittal pelvic dynamics mainly consist of the pelvis rotating anteriorly or posteriorly while the hips flexes, and this affects the femoroacetabular or THA configuration. Thus far, it is unknown how the acetabular cup of the THA in the individual patient reorients with changing sagittal pelvic dynamics. QUESTIONS/PURPOSES: The aim of this study was to validate a method that establishes the three-dimensional (3-D) acetabular cup orientation with changing sagittal pelvic dynamics and describe these changes during functional pelvic dynamics. METHODS: A novel trigonometric mathematical model, which was incorporated into an easy-to-use tool, was tested. The model connected sagittal tilt, transverse version, and coronal inclination of the acetabular cup during sagittal pelvic tilt. Furthermore, the effect of sagittal pelvic tilt on the 3-D reorientation of acetabular cups was simulated for cups with different initial positions. Twelve pelvic CT images of patients who underwent THA were taken and rotated around the hip axis to different degrees of anterior and posterior sagittal pelvic tilt (± 30°) to simulate functional pelvic tilt in various body positions. For each simulated pelvic tilt, the transverse version and coronal inclination of the cup were manually measured and compared with those measured in a mathematical model in which the 3-D cup positions were calculated. Next, this model was applied to different acetabular cup positions to simulate the effect of sagittal pelvic dynamics on the 3-D orientation of the acetabular cup in the coronal and transverse plane. After pelvic tilt was applied, the intraclass correlation coefficients of 108 measured and calculated coronal and transverse cup orientation angles were 0.963 and 0.990, respectively, validating the clinical use of the mathematical model. RESULTS: The changes in 3-D acetabular cup orientation by functional pelvic tilt differed substantially between cups with different initial positions; the change in transverse version was much more pronounced in cups with low coronal inclination (from 50° to -29°) during functional pelvic tilt than in cups with a normal coronal inclination (from 39° to -11°) or high coronal inclination (from 31° to 2°). However, changes in coronal inclination were more pronounced in acetabular cups with high transverse version. CONCLUSION: Using a simple algorithm to determine the dynamic 3-D reorientation of the acetabular cup during functional sagittal pelvic tilt, we demonstrated that the 3-D effect of functional pelvic tilt is specific to the initial acetabular cup orientation and thus per THA patient. CLINICAL RELEVANCE: Future studies concerning THA (in)stability should not only include the initial acetabular cup orientation, but also they need to incorporate the effect of sagittal pelvic dynamics on the individual 3-D acetabular cup orientation. Clinicians can also use the developed tool, www.3d-hip.com, to calculate the acetabular cup's orientation in other instances, such as for patients with spinopelvic imbalance.

Health-related quality of life after sleeve gastrectomy equal to Roux-en-Y gastric bypass patients?

PURPOSE: Sleeve gastrectomy (SG) is the most popular type of bariatric surgery. It has often been compared to Roux-en-Y gastric bypass (RYGB) in terms of clinical outcomes. However, health-related quality of life (HRQoL) has been sparsely studied after SG. The goal was to study HRQoL after SG using a generic (RAND-36) and an obesity-specific (impact of weight on quality of life-lite, IWQOL-lite) questionnaire and to compare the results with RYGB. METHODS: HRQoL and weight were measured before and 9, 15, and 24 months after surgery. RAND-36 physical health summary (PHS) and mental health summary (MHS), and IWQOL-lite total score were calculated. A mixed model analysis was conducted to study the change in HRQoL and compare SG with RYGB. RESULTS: A total of 219 patients (8.7%) underwent a SG and 2309 patients (91.3%) a RYGB. PHS, MHS, and IWQOL-lite significantly improved after SG when comparing baseline to all follow-up moments (p < 0.001 in all). There were no significant differences when comparing SG with RYGB: change in PHS (ß - 0.10, 95% CI - 1.24 to 1.04, p = 0.861), MHS (ß - 0.51, 95% CI - 1.56 to 0.52, p = 0.330), and IWQOL-lite (ß 0.310, 95% CI - 0.85 to 1.47, p = 0.601). CONCLUSION: HRQoL significantly improved after SG. In the included populations, weight loss was comparable and the extent to which HRQoL improved did not differ between SG and RYGB, when measured with the RAND-36 or IWQOL-lite. This might be partly caused by the fact that these questionnaires do not assess specific bariatric HRQoL and/or complaints.

Political and public acceptability of a sugar-sweetened beverages tax: a mixed-method systematic review and meta-analysis.

BACKGROUND: Taxation of sugar-sweetened beverages (SSBs), as a component of a comprehensive strategy, has emerged as an apparent effective intervention to counteract the rising prevalence of overweight and obesity. Insight into the political and public acceptability may help adoption and implementation in countries with governments that are considering an SSBs tax. Hence, we aimed to conduct a systematic review and meta-analysis to synthesize the existing qualitative and quantitative literature on political and public acceptability of an SSBs tax. METHODS: Four electronic databases (PubMed, Embase, Scopus, Web of Science) were searched until November 2018. The methodological quality of the included studies was assessed using the Mixed Methods Appraisal Tool. Qualitative studies were analyzed using a thematic synthesis. Quantitative studies were analyzed using a random-effects meta-analysis for the pooling of proportions. RESULTS: Thirty-seven articles reporting on forty studies were eligible for inclusion. Five themes derived from the thematic synthesis: (i) beliefs about effectiveness and cost-effectiveness, (ii) appropriateness, (iii) economic and socioeconomic benefit, (iv) policy adoption and implementation, and (v) public mistrust of the industry, government and public health experts. Results of the meta-analysis indicated that of the public 42% (95% CI = 0.38-0.47) supports an SSBs tax, 39% (0.29-0.50) supports an SSBs tax as a strategy to reduce obesity, and 66% (0.60-0.72) supports an SSBs tax if revenue is used for health initiatives. CONCLUSIONS: Beliefs about effectiveness and cost-effectiveness, appropriateness, economic and socioeconomic benefit, policy adoption and implementation, and public mistrust of the industry, government and public health experts have important implications for the political and public acceptability of an SSBs tax. We provide recommendations to increase acceptability and enhance successful adoption and implementation of an SSBs tax: (i) address inconsistencies between identified beliefs and scientific literature, (ii) use raised revenue for health initiatives, (iii) communicate transparently about the true purpose of the tax, and (iv) generate political priority for solutions to the challenges to implementation.

Mediators of the effectiveness of a kindergarten-based, family-involved intervention on pre-schoolers' snacking behaviour: the ToyBox-study.

OBJECTIVE: The present study aimed to explore the mediating role of family-related determinants on the effects of the ToyBox-intervention on pre-school children's consumption of healthy and unhealthy snacks. DESIGN: The ToyBox-intervention was a kindergarten-based, family-involved intervention with a cluster-randomized design, aiming to promote healthy lifestyle behaviours to prevent obesity at pre-school age. SETTING: Kindergartens (n 309) in six European countries. SUBJECTS: A total of 6290 pre-schoolers and their families participated in the ToyBox-intervention in 2012-2013 and data from 5212 pre-schoolers/families were included in the current analyses. RESULTS: Even though the total effect of the ToyBox-intervention on healthy and unhealthy snacking was not significant, the ToyBox-intervention significantly improved parental rule setting on children's unhealthy snack consumption (i.e. restriction of snacking while watching television and permission only at certain occasions) and parental consumption of unhealthy snacks, while it increased parental knowledge on snacking recommendations. Regarding healthy snacking, the ToyBox-intervention improved children's attitude towards fruit and vegetables (F&V). All previously mentioned family-related determinants mediated the intervention effects on pre-schoolers' consumption of healthy and unhealthy snacks. Almost all family-related determinants examined in the study were independently associated with pre-schoolers' consumption of healthy and unhealthy snacks. CONCLUSIONS: The intervention was effective in improving relevant family-related determinants. Interventions aiming to promote F&V consumption and limit the consumption of unhealthy snacks in pre-schoolers should target on these mediators, but also identify new family-, school- or peer-related determinants, to enhance their effectiveness.

Modeling Longitudinal Relationships Between Habit and Physical Activity: Two Cross-Lagged Panel Design Studies in Older Adults.

These longitudinal studies in older adults targeted mediated relationships between habit and physical activity (PA). In The Netherlands two independent studies were conducted among 1976 (Study 1: Mage = 63.63, SD = 8.66, 30% functional limitations) and 2140 (Study 2: Mage = 62.75, SD = 8.57, 45% functional limitations) adults aged 50 years or older. Cross-lagged panel designs were applied to examine whether habit mediates the relationship between prior and later PA and whether PA simultaneously mediates the relationship between prior and later habit. Data on habit and PA were collected by means of questionnaires at baseline (t0) and at 6 (t1) and 12 (t2) months after baseline measurement. Results of structural equation modeling analyses were not unambiguous. Indications for the existence of both hypothesized mediation effects were found, but no clear, unequivocal pattern appeared. Somewhat more support was found for the PA-habit-PA path than for the habit-PA-habit path. More research is needed to draw more definitive conclusions.

What features do Dutch university students prefer in a smartphone application for promotion of physical activity? A qualitative approach.

BACKGROUND: The transition from adolescence to early adulthood is a critical period in which there is a decline in physical activity (PA). College and university students make up a large segment of this age group. Smartphones may be used to promote and support PA. The purpose of this qualitative study was to explore Dutch students' preferences regarding a PA application (PA app) for smartphones. METHODS: Thirty Dutch students (aged 18-25 years) used a PA app for three weeks and subsequently attended a focus group discussion (k = 5). To streamline the discussion, a discussion guide was developed covering seven main topics, including general app usage, usage and appreciation of the PA app, appreciation of and preferences for its features and the sharing of PA accomplishments through social media. The discussions were audio and video recorded, transcribed and analysed according to conventional content analysis. RESULTS: The participants, aged 21 ± 2 years, were primarily female (67%). Several themes emerged: app usage, technical aspects, PA assessment, coaching aspects and sharing through social media. Participants most often used social networking apps (e.g., Facebook or Twitter), communication apps (e.g., WhatsApp) and content apps (e.g., news reports or weather forecasts). They preferred a simple and structured layout without unnecessary features. Ideally, the PA app should enable users to tailor it to their personal preferences by including the ability to hide features. Participants preferred a companion website for detailed information about their accomplishments and progress, and they liked tracking their workout using GPS. They preferred PA apps that coached and motivated them and provided tailored feedback toward personally set goals. They appreciated PA apps that enabled competition with friends by ranking or earning rewards, but only if the reward system was transparent. They were not willing to share their regular PA accomplishments through social media unless they were exceptionally positive. CONCLUSIONS: Participants prefer PA apps that coach and motivate them, that provide tailored feedback toward personally set goals and that allow competition with friends.

The role of perceived barriers in explaining socio-economic status differences in adherence to the fruit, vegetable and fish guidelines in older adults: a mediation study.

OBJECTIVE: We aimed to identify barriers for meeting the fruit, vegetable and fish guidelines in older Dutch adults and to investigate socio-economic status (SES) differences in these barriers. Furthermore, we examined the mediating role of these barriers in the association between SES and adherence to these guidelines. DESIGN: Cross-sectional. SETTING: Longitudinal Aging Study Amsterdam (LASA), the Netherlands. SUBJECTS: We used data from 1057 community-dwelling adults, aged 55-85 years. SES was measured by level of education and household income. An FFQ was used to assess dietary intake and barriers were measured with a self-reported lifestyle questionnaire. RESULTS: Overall, 48.9 % of the respondents perceived a barrier to adhere to the fruit guideline, 40.0 % for the vegetable and 51.1 % for the fish guideline. The most frequently perceived barriers to meet the guidelines were the high price of fruit and fish and a poor appetite for vegetables. Lower-SES groups met the guidelines less often and perceived more barriers. The association between income and adherence to the fruit guideline was mediated by 'perceiving any barrier to meet the fruit guideline' and the barrier 'dislike fruit'. The association between income and adherence to the fish guideline was mediated by 'perceiving any barrier to meet the fish guideline' and the barrier 'fish is expensive'. CONCLUSIONS: Perceived barriers for meeting the dietary guidelines are common in older adults, especially in lower-SES groups. These barriers and in particular disliking and cost concerns explained the lower adherence to the guidelines for fruit and fish in lower-income groups in older adults.

The association between daily steps and health, and the mediating role of body composition: a pedometer-based, cross-sectional study in an employed South African population.

BACKGROUND: Walking is recognized as an easily accessible mode of physical activity and is therefore supported as a strategy to promote health and well-being. To complement walking, pedometers have been identified as a useful tool for monitoring ambulatory physical activity, typically measuring total steps/day. There is, however, little information concerning dose-response for health outcomes in relation to intensity or duration of sustained steps. We aimed to examine this relationship, along with factors that mediate it, among employed adults. METHODS: A convenience sample, recruited from work-site health risk screening (N = 312, 37 ± 9 yrs), wore a pedometer for at least three consecutive days. Steps were classified as "aerobic" (≥100 steps/minute and ≥10 consecutive minutes) or "non-aerobic" (<100 steps/minute and/or <10 consecutive minutes). The data were sub-grouped according to intensity-based categories i.e. "no aerobic activity", "low aerobic activity" (1-20 minutes/day of aerobic activity) and "high aerobic activity" (≥21 minutes/day of aerobic activity), with the latter used as a proxy for current PA guidelines (150-minutes of moderate-intensity PA per week). Health outcomes included blood pressure, body mass index, percentage body fat, waist circumference, blood cholesterol and blood glucose. Analysis of covariance, adjusting for age, gender and total steps/day were used to compare groups according to volume and intensity-based steps categories. A further analysis compared the mediation effect of body fat estimates (percentage body fat, body mass index and waist circumference) on the association between steps and health outcomes, independently. RESULTS: Average steps/day were 6,574 ± 3,541; total steps/day were inversely associated with most health outcomes in the expected direction (p < 0.05). The "no aerobic activity" group was significantly different from the "low aerobic activity" and "high aerobic activity" in percentage body fat and diastolic blood pressure only (P < 0.05). Percentage body fat emerged as the strongest mediator of the relationship between steps and outcomes, while body mass index showed the least mediation effect. CONCLUSION: The study provides a presentation of cross-sectional pedometer data that relate to a combination of intensity and volume-based steps/day and its relationship to current guidelines. The integration of volume, intensity and duration of ambulatory physical activity in pedometer-based messages is of emerging relevance.

Comparison of energy balance-related behaviours and measures of body composition between Turkish adolescents in Turkey and Turkish immigrant adolescents in the Netherlands.

OBJECTIVE: To explore the influences of migration to a Western country on obesity and related risk factors by comparing measures of body composition and energy balance-related behaviours between Turkish adolescents in Turkey (TR-TR) and adolescents from Turkish immigrant ethnicity in the Netherlands (TR-NL). DESIGN: Cross-sectional survey or baseline intervention data from six Dutch school-based studies and one Turkish study. SETTING: Primary and secondary schools. SUBJECTS: A total of 915 (49 % girls; mean age 13·1 (sd 0·8) years) TR-TR adolescents and 433 (51 % girls; mean age 11·7 (sd 1·3) years) TR-NL adolescents were included. Outcome measures were self-reported sugar-containing beverage consumption, fruit and vegetable intake, screen time, physical activity, measured body height and weight, BMI, waist and hip circumferences, and skinfold thicknesses. RESULTS: Our data showed that more TR-NL adolescents were overweight (31 % v. 26 %) and obese (9 % v. 6 %) and had significantly higher mean BMI (21·1 v. 20·0 kg/m2), waist circumference (72·2 v. 71·3 cm) and suprailiac skinfold thickness (19·8 v. 13·1 mm) than TR-TR adolescents. TR-NL adolescents reported significantly higher sugar-containing beverage consumption (1173 v. 115 ml/d), less fruit and vegetable intake (295 v. 647 g/d), less screen time (253 v. 467 min/d) and higher physical activity levels (61 v. 27 min/d) than TR-TR adolescents. CONCLUSIONS: Immigrant adolescents in the Netherlands were more often overweight and had a less favourable dietary pattern than their peers in Turkey, while their physical activity and screen time patterns were more favourable. These results suggest that adolescents from Turkish immigrant ethnicity in the Netherlands have adopted lifestyles towards the host culture.

Predicting fruit consumption: the role of habits, previous behavior and mediation effects.

BACKGROUND: This study assessed the role of habits and previous behavior in predicting fruit consumption as well as their additional predictive contribution besides socio-demographic and motivational factors. In the literature, habits are proposed as a stable construct that needs to be controlled for in longitudinal analyses that predict behavior. The aim of this study is to provide empirical evidence for the inclusion of either previous behavior or habits. METHODS: A random sample of 806 Dutch adults (>18 years) was invited by an online survey panel of a private research company to participate in an online study on fruit consumption. A longitudinal design (N = 574) was used with assessments at baseline and after one (T2) and two months (T3). Multivariate linear regression analysis was used to assess the differential value of habit and previous behavior in the prediction of fruit consumption. RESULTS: Eighty percent of habit strength could be explained by habit strength one month earlier, and 64% of fruit consumption could be explained by fruit consumption one month earlier. Regression analyses revealed that the model with motivational constructs explained 41% of the behavioral variance at T2 and 38% at T3. The addition of previous behavior and habit increased the explained variance up to 66% at T2 and to 59% at T3. Inclusion of these factors resulted in non-significant contributions of the motivational constructs. Furthermore, our findings showed that the effect of habit strength on future behavior was to a large extent mediated by previous behavior. CONCLUSIONS: Both habit and previous behavior are important as predictors of future behavior, and as educational objectives for behavior change programs. Our results revealed less stability for the constructs over time than expected. Habit strength was to a large extent mediated by previous behavior and our results do not strongly suggest a need for the inclusion of both constructs. Future research needs to assess the conditions that determine direct influences of both previous behavior and habit, since these influences may differ per type of health behavior, per context stability in which the behavior is performed, and per time frame used for predicting future behavior.

Post-intervention effects on screen behaviours and mediating effect of parental regulation: the HEalth In Adolescents study--a multi-component school-based randomized controlled trial.

BACKGROUND: To improve effectiveness of future screen behaviour interventions, one needs to know whether an intervention works via the proposed mediating mechanisms and whether the intervention is equally effective among subgroups. Parental regulation is identified as a consistent correlate of screen behaviours, but prospective evidence as well as the mediation role of parental regulation is largely lacking. This study investigated post-intervention main effects on screen behaviours in the HEIA-intervention--a Norwegian school-based multiple-behaviour study, as well as mediation effects of parental regulation by adolescents' and parents' report. In addition, moderating effects of gender and weight status on the intervention and mediating effects were explored. METHODS: Participating schools were randomized to control (n=25) or intervention (n=12) condition. Adolescents (n=908 Control; 510 Intervention) self-reported their weekday and weekend TV-viewing and computer/game-use. Change in adolescents' behaviours was targeted through school and parents. Adolescents, mothers (n=591 Control; 244 Interventions) and fathers (n=469 Control; 199 Intervention) reported parental regulation of the screen behaviours post-intervention (at 20 month). The product-of-coefficient test using linear regression analysis was conducted to examine main and mediating effects. RESULTS: There was no intervention effect on the screen behaviours in the total sample. Gender moderated effect on weekend computer/game-use, while weight status moderated the effect on weekday TV-viewing and computer/game-use. Stratified analyses showed a small favourable intervention effect on weekday TV-viewing among the normal weight. Parental regulation did not mediate change in the screen behaviours. However, stronger parental regulation was associated with less TV-viewing and computer/game-use with effects being conditional on adolescents' versus parental reports. Parental regulation of the screen behaviours, primarily by the parental report, was associated with change in the respective behaviours. CONCLUSION: Multiple behaviour intervention may not affect all equally well, and the effect may differ by weight status and gender. In future interventions parents should be encouraged to regulate their adolescents' TV-viewing and computer/game-use on both weekdays and weekends as parental regulation was identified as a determinant of these screen behaviours. However, future intervention studies may need to search for more effective intervention strategies targeting parental regulation. TRIAL REGISTRATION: Current Controlled Trials ISRCTN98552879.