Barriers to and facilitators of a just-in-time adaptive intervention for respiratory illness in cerebral palsy: a qualitative study.

OBJECTIVE: To understand caregiver, healthcare professional and national expert perspectives on implementation of a just-in-time adaptive intervention, RE-PACT (Respiratory Exacerbation-Plans for Action and Care Transitions) to prevent respiratory crises in severe cerebral palsy. DESIGN: Qualitative research study. SETTING: Paediatric complex care programmes at two academic medical institutions. PARTICIPANTS: A total of n=4 focus groups were conducted with caregivers of children with severe cerebral palsy and chronic respiratory illness, n=4 with healthcare professionals, and n=1 with national experts. METHODS: Participants viewed a video summarising RE-PACT, which includes action planning, mobile health surveillance of parent confidence to avoid hospitalisation and rapid clinical response at times of low confidence. Moderated discussion elicited challenges and benefits of RE-PACT's design, and inductive thematic analysis elicited implementation barriers and facilitators. RESULTS: Of the 19 caregivers recruited, nearly half reported at least one hospitalisation for their child in the prior year. Healthcare professionals and national experts (n=26) included physicians, nurses, respiratory therapists, social workers and researchers. Four overarching themes and their barriers/facilitators emphasised the importance of design and interpersonal relationships balanced against health system infrastructure constraints. Intervention usefulness in crisis scenarios relies on designing action plans for intuitiveness and accuracy, and mobile health surveillance tools for integration into daily life. Trust, knowledge, empathy and adequate clinician capacity are essential components of clinical responder-caregiver relationships. CONCLUSIONS: RE-PACT's identified barriers are addressable. Just-in-time adaptive interventions for cerebral palsy appear well-suited to address families' need to tailor intervention content to levels of experience, preference and competing demands.

Prospectively predicting naturalistic exposure to fitspiration and thinspiration in young women with disordered eating by leveraging an ecological momentary assessment design.

OBJECTIVE: Although a growing body of research has examined the impacts of ED-salient content, such as fitspiration and thinspiration, on eating disorder (ED) symptoms, there is less known about the characteristics of who may be at risk for accessing this content on Instagram. Current research is limited by cross-sectional and retrospective designs. This prospective study used ecological momentary assessment (EMA) to predict naturalistic exposure to ED-salient content on Instagram. METHODS: Female university students with disordered eating (N = 171, Mage = 20.23, SD = 1.71, range = 18-25) completed a baseline session, followed by a seven-day EMA protocol, in which they reported on Instagram use and exposure to fitspiration and thinspiration. Mixed-effects logistical regressions were used to predict exposure to ED-salient content on Instagram from four principal components (e.g., behavioral ED symptoms and trait social comparison) controlling for duration of Instagram use (i.e., dose) and day of study. RESULTS: Duration of use was positively associated with all types of exposure. Purging/cognitive restraint and excessive exercise/muscle building prospectively predicted access to any ED-salient content and fitspiration only. Restricting positively predicted thinspiration only access. Purging/cognitive restraint positively predicted accessing fitspiration and thinspiration (dual exposure). Day of study was negatively associated with any exposure, fitspiration only, and dual exposure. CONCLUSIONS: Baseline ED behaviors were differentially associated with exposure to ED-salient Instagram content; however, duration of use was also a significant predictor. Limiting use of Instagram may be important for young women with disordered eating to reduce probability of encountering ED-salient content.

The Development and Initial Validation of Items to Assess Parent Fear of Nighttime Hypoglycemia.

OBJECTIVE: Parents of youth with type 1 diabetes (T1D) are fearful their children will experience nighttime hypoglycemia. Currently, the Hypoglycemia Fear Survey for Parents (HFS-P) lacks items that specifically assess parents' nighttime fear. This study aimed to fill this gap by rigorously identifying new items to specifically assess parent fear of nighttime hypoglycemia and then examine the psychometric properties of the revised Hypoglycemia Fear Survey for Parents including Nighttime Fear (HFS-P-NF). METHODS: For Phase 1, we recruited 10 pediatric diabetes providers and 15 parents/caregivers of youth with T1D to generate items related to fear of nighttime hypoglycemia. For Phase 2, we recruited an additional 20 parents/caregivers to pilot-test the newly generated items. For Phase 3, we recruited another 165 parents/caregivers to evaluate structural validity via confirmatory factor analyses, reliability, and content validity of the revised HFS-P-NF. RESULTS: In Phase 1, we generated 54 items. In Phase 2, we removed 34 items due to violations of distributional normality and nonsignificant correlations. In Phase 3, a four-factor model reflecting behaviors maintaining high glucose, helplessness, negative social consequences, and nighttime worries was the best fitting model for the HFS-P-NF. The new items demonstrated strong internal consistency (α = 0.96) and strong to moderate relationships with criterion and content validity measures. CONCLUSION: The current study provides initial evidence of validity and reliability for new items on the HFS-P-NF that broadened the conceptualization of parent fear of nighttime hypoglycemia. These findings are important to clinicians who may consider screening for parent fear of nighttime hypoglycemia more comprehensively.

Hedonic Appetite, Affect, and Loss of Control Eating: Macrotemporal and Microtemporal Associations in Adolescents.

OBJECTIVE: Loss of control eating (LOC) is a dysregulated eating behavior relevant to eating disorders and weight-related health concerns. Hedonic appetite and affect (positive/negative) are dynamic microtemporal processes that influence LOC, but they have been studied predominantly in a static, macrotemporal manner. The present study examined associations of hedonic appetite and positive/negative affect, on macrotemporal and microtemporal levels, with LOC in adolescents. METHODS: Adolescent participants 13-18 years old (n = 43; Mage = 15.1, SD = 1.6; 69.8% female) completed smartphone surveys for 6 evenings, assessing LOC, hedonic appetite, and positive/negative affect. Scores on items were calculated to create microtemporal and macrotemporal assessments of these constructs. Multilevel models were run to examine associations between hedonic appetite and positive/negative affect with LOC. RESULTS: Both macrotemporal and microtemporal hedonic appetite were significantly positively related to LOC (ß = .73, p < .001; ß = .47, p < .001, respectively). Macrotemporal positive affect was significantly negatively associated with LOC (ß = -.09, p < .001). Macrotemporal negative affect was significantly positively associated with LOC (ß = .13, p < .001). No significant relationships emerged between microtemporal positive/negative affect and LOC. CONCLUSIONS: Hedonic appetite appears to be associated with LOC on both microtemporal and macrotemporal levels, suggesting that both momentary fluctuations and having higher hedonic appetite than others can be risk factors for LOC. However, affect appears to be associated with LOC only at the macrotemporal level. Findings may inform theoretical work and clinical and research assessment strategies.

Temporal discounting modifies the effect of microtemporal hedonic hunger on food consumption: An ecological momentary assessment study.

INTRODUCTION: Steeper delay discounting, or preference for small rewards sooner versus larger rewards later, has been linked to disinhibited eating and obesity. The overconsumption of food may also be motivated by hedonic hunger, or the drive to consume foods for pleasure rather than energy need. The present study hypothesized that hedonic hunger would modify the relation between temporal discounting and palatable food consumption. METHODS: Seventeen adolescents between the ages of 13-18 (M = 15.12,SD = 1.80) completed a temporal discounting measure at baseline followed by daily ecological momentary assessments of food intake (e.g., self-reported servings of sweet, starchy, fatty, fast foods) and hedonic hunger for 20 days on a mobile phone. Multilevel models examined between-person (BP) and within-person (WP) hedonic hunger, monetary temporal discounting, and their interactions, on food consumption. RESULTS: The models for sweet, starchy, and fast food consumption had significant interactions between WP hedonic hunger and temporal discounting. For each of these interactions, those with average-or-lower temporal discounting rates were at less risk of consuming sweet, starchy, and fast foods when hedonic hunger was higher than typical while those with high rates of discounting were at higher risk of consuming these types of foods when hedonic hunger was elevated. CONCLUSION: Increases in daily hedonic hunger may confer risk for sweet, starchy, and fast food consumption. However, preference for larger rewards later may serve as a protective factor against consumption of these palatable foods. Future studies should further investigate this and other reward-driven processes that may influence food consumption.

Cash-Only INcentives to promote insulin DOSE engagement: A protocol paper for the pilot randomized controlled trial of COIN2DOSE.

BACKGROUND: Most adolescents with type 1 diabetes (T1D) do not achieve a glycated hemoglobin (HbA1c) <7.0%, which is the current clinical target. mHealth can offer a scalable and age-appropriate delivery method for behavioral interventions to lower adolescents' HbA1c levels, while applying established behavior change and behavioral economics theories can enhance scientific rigor. METHODS: We aim to conduct a pilot randomized clinical trial of a novel mHealth intervention called Coin2Dose (Cash-Only INcentives To promote insulin DOSE engagement), in a sample of youth with T1D: 1) to obtain measures of feasibility and acceptability and 2) to examine preliminary efficacy versus a standard care control group based on differences in youth's daily BOLUS scores, HbA1c levels, and Time in Range (TIR) at post-intervention and 3-month post-intervention follow-up. This pilot RCT is already registered in http://ClinicalTrials.gov (NCT#05280184). RESULTS: Our pilot will recruit youth with T1D 11-17 years-old who use an insulin pump or Bluetooth connected insulin pen and have an average daily BOLUS score ≤2.5. Youth randomized to Coin2Dose will receive the intervention for 12 weeks followed by a 12-week maintenance period. The pilot is scheduled to start July 2022 and to conclude in 2025. DISCUSSION: At the conclusion of the pilot, we will have information about the feasibility and acceptability of two different behavioral economic incentive structures for improving BOLUS scores. The work is anticipated to progress to final efficacy trial. We will disseminate study results through presentations at local, national, and international conferences and through peer-reviewed diabetes and psychology journals.

Location-specific psychosocial and environmental correlates of physical activity and sedentary time in young adolescents: preliminary evidence for location-specific approaches from a cross-sectional observational study.

BACKGROUND: A better understanding of the extent to which psychosocial and environmental correlates of physical activity are specific to locations would inform intervention optimization. PURPOSE: To investigate cross-sectional associations of location-general and location-specific variables with physical activity and sedentary time in three common locations adolescents spend time. METHODS: Adolescents (N = 472,Mage = 14.1,SD = 1.5) wore an accelerometer and global positioning systems (GPS) tracker and self-reported on psychosocial (e.g., self-efficacy) and environmental (e.g., equipment) factors relevant to physical activity and sedentary time. We categorized each survey item based on whether it was specific to a location to generate psychosocial and environmental indices that were location-general or specific to either school, non-school, or home location. Physical activity (MVPA) and sedentary time were based on time/location match to home, school, or all "other" locations. Mixed-effects models investigated the relation of each index with location-specific activity. RESULTS: The location-general and non-school physical activity psychosocial indices were related to greater MVPA at school and "other" locations. The school physical activity environment index was related to greater MVPA and less sedentary time at school. The home activity environment index was related to greater MVPA at home. The non-school sedentary psychosocial index was related to less sedentary time at home. Interactions among indices revealed adolescents with low support on one index benefited (i.e., exhibited more optimal behavior) from high support on another index (e.g., higher scores on the location-general PA psychosocial index moderated lower scores on the home PA environment index). Concurrent high support on two indices did not provide additional benefit. CONCLUSIONS: No psychosocial or environment indices, including location-general indices, were related to activity in all locations. Most of the location-specific indices were associated with activity in the matching location(s). These findings provide preliminary evidence that psychosocial and environmental correlates of activity are location specific. Future studies should further develop location-specific measures and evaluate these constructs and whether interventions may be optimized by targeting location-specific psychosocial and environmental variables across multiple locations.

Microtemporal Relationships in the Fear Avoidance Model: An Ecological Momentary Assessment Study.

OBJECTIVES: Current literature in pediatric pain evaluates the Fear Avoidance model (FAM) pathways at the trait (or macrotemporal) level, but it is unknown if these pathways also occur at the state (or microtemporal) level. Identifying microtemporal processes can improve our understanding of how the relationships within the Fear Avoidance constructs vary when specific Fear Avoidance variables wax and wane. We hypothesized that changes in FAM constructs would be associated with changes in the next variable in the sequence on a microtemporal level, including: (1) higher pain when there is more pain-related fear, (2) higher pain-related fear when there is more avoidance, and (3) higher avoidance when there is more reported disability. METHODS: 71 pediatric patients with chronic abdominal pain ( M =13.34 y, SD=2.67 y) reported pain severity, pain-related fear, and avoidance via ecological momentary assessments over 14 days. RESULTS: Our results indicated significant microtemporal relationships between Fear Avoidance constructs for pain predicting pain-related fear, pain-related fear predicting avoidance, and avoidance predicting disability. DISCUSSION: The current study suggests that the ways in which the FAM is related to various aspects of pain functioning differs on a state-level, which adds new clinical and research opportunities.

Caregiving and Confidence to Avoid Hospitalization for Children with Medical Complexity.

OBJECTIVE: To test associations between parent-reported confidence to avoid hospitalization and caregiving strain, activation, and health-related quality of life (HRQOL). STUDY DESIGN: In this prospective cohort study, enrolled parents of children with medical complexity (n = 75) from 3 complex care programs received text messages (at random times every 2 weeks for 3 months) asking them to rate their confidence to avoid hospitalization in the next month. Low confidence, as measured on a 10-point Likert scale (1 = not confident; 10 = fully confident), was defined as a mean rating <5. Caregiving measures included the Caregiver Strain Questionnaire, Family Caregiver Activation in Transition (FCAT), and caregiver HRQOL (Medical Outcomes Study Short Form 12 [SF12]). Relationships between caregiving and confidence were assessed with a hierarchical logistic regression and classification and regression trees (CART) model. RESULTS: The parents were mostly mothers (77%) and were linguistically diverse (20% spoke Spanish as their primary language), and 18% had low confidence on average. Demographic and clinical variables had weaker associations with confidence. In regression models, low confidence was associated with higher caregiver strain (aOR, 3.52; 95% CI, 1.45-8.54). Better mental HRQOL was associated with lower likelihood of low confidence (aOR, 0.89; 95% CI, 0.80-0.97). In the CART model, higher strain similarly identified parents with lower confidence. In all models, low confidence was not associated with caregiver activation (FCAT) or physical HRQOL (SF12) scores. CONCLUSIONS: Parents of children with medical complexity with high strain and low mental HRQOL had low confidence in the range in which intervention to avoid hospitalization would be warranted. Future work could determine how adaptive interventions to improve confidence and prevent hospitalizations should account for strain and low mental HRQOL.

Applying Behavioral Economics Theories to Interventions for Persons with Diabetes.

PURPOSE OF REVIEW: To introduce behavioral economics (BE), provide a description of how recent prevention and treatment interventions in persons with diabetes have incorporated BE in their intervention strategies, and discuss how BE could be used to inform new treatments for the clinical setting or research. RECENT FINDINGS: In most of the trials described, researchers incorporated BE into their design in the form of incentives, which can align with present bias, optimism bias, and loss aversion. With only two exceptions, these trials reported preliminary support for using incentives to promote lifestyle modifications and diabetes-related tasks. Additionally, two trials reported promising results for behavior change strategies informed by default bias, while three trials reported promising results for behavior change strategies informed by social norms. Recent trials incorporating BE in prevention and treatment interventions for persons with diabetes generally report promising results, though gaps exist for research and clinical deployment.

Parent-Child Conflict Moderates the Relationship Between Executive Functioning and Child Disruptive Behaviors in Youth with T1D.

Executive function (EF) skills, parent-child conflict, and high blood glucose (BG) may impact child externalizing behaviors. We examined these child and parent factors in families of 5-9 year olds with recent-onset type 1 diabetes (T1D). Parents (N = 125) reported child EF, child externalizing behaviors, and conflict regarding T1D-specific tasks. We used self-monitoring BG uploads to calculate the percentage of time children had high BG (> 180 mg/dl). We entered data into a moderated path analysis using MPlus8. The path analysis revealed a positive direct effect for parent-reported child EF and child externalizing behavior (p < .01). Further, T1D-specific conflict moderated the positive association between parent-reported child EF and child externalizing behaviors (p < .05). Early screening of child EF, externalizing behavior, and family conflict may be particularly important in the recent-onset period of T1D. The introduction of T1D-related conflict after diagnosis may impact child externalizing behavior and limited child EF skills that pre-date diagnosis.

Daily adherence variability and psychosocial differences in adolescents with asthma: a pilot study.

Adolescents with asthma endorse psychosocial difficulties as barriers to inhaled corticosteroid adherence. This study examined patterns of variability in adherence and within-person associations of psychosocial variables with adherence across days. Participants included twenty-five adolescents (Mage = 14.7, SD = 1.68; 48% male) with persistent asthma. We measured adherence via electronic monitoring. Adolescents completed daily surveys measuring asthma symptoms, stress, mood, and affect. We examined within-person differences in the effect of symptoms and psychosocial variables on adherence. Adherence decreased over time. The addition of a random slope improved model fit (- 2ΔLL(1) = 9.36, p < .01). Greater asthma symptoms were significantly associated with higher adherence at the within-person level and with lower adherence between persons. We observed evidence of individual differences in the associations of stress and affect with adherence. Within-person, day-level fluctuations in adherence occur. Symptoms and psychosocial variables may influence adherence. Individually tailored interventions may effectively address nonadherence.

Meta-Analysis of Adherence Promotion Interventions in Pediatric Asthma.

BACKGROUND: Youth with asthma commonly have suboptimal adherence to inhaled corticosteroids (ICS). It is critical to systematically evaluate the effectiveness of ICS adherence promotion interventions and discern which techniques are most effective. OBJECTIVE: This study aims to (1) quantify the extent to which interventions improve ICS adherence in pediatric asthma, (2) explore differences in effect size estimates based on intervention and study characteristics, and (3) characterize the risk of bias across interventions. METHODS: We conducted literature searches across five databases. Included studies quantitatively measured ICS adherence as an intervention outcome among youth (<18 years old) diagnosed with asthma and were published after 1997. We analyzed aggregate effect sizes and moderator variables using random-effects models and characterized risk of bias using the Cochrane Collaboration tool. RESULTS: Thirty-three unique studies met inclusion criteria. At post-intervention, the aggregate effect size for pediatric ICS adherence promotion interventions was small but significant (n = 33, g = 0.39, 95% confidence interval [CI] = 0.24-0.54); however, the aggregate effect size at follow-up was not statistically significant (n = 6, g = 0.38, 95% CI = -0.08 to 0.83). Method of adherence measurement and intervention format were significant moderators. Most interventions had a high risk of performance bias and an unclear risk of bias in one or more domains. CONCLUSIONS: ICS adherence promotion interventions are effective among youth with asthma. Additional longitudinal research is needed to quantify a more precise measure of intervention effectiveness over time, and moderators of intervention effectiveness should be reassessed as the literature base expands.

Prospective quality of life outcomes in pediatric fecal incontinence following bowel management.

BACKGROUND: Severe fecal incontinence (FI) is common in patients both with and without anorectal malformations. Whether a formal bowel management program (BMP) has significant effects on FI, psychosocial development of the child, and caregiver stress is poorly understood. We hypothesize that BMP participation results in long-term clinical and quality of life (QOL) improvements for patients and caregivers. METHODS: Using a prospective cohort study over three years, 342 children (age 3-12 years) and caregivers were followed for one year after attending a week-long BMP, during which a regimen was tailored to promote daily stool evacuation.FI QOL was measured with the validated Cincinnati Fecal Incontinence Scale (CINCY-FIS), evaluating multiple subscales, including parental stress. Scores were obtained at multiple timepoints following BMP (baseline, 2 weeks, 3 months, 1 year). RESULTS: Within 2 weeks, BMP participation significantly improved FI with increased frequency of daily daytime voluntary bowel movements (20%-70%, p < 0.001) and decreased daily daytime and nighttimeinvoluntary bowel movements (60%-20%, p < 0.001; 30%-10%, p < 0.05). Marked improvements in CINCY-FIS were observed across multiple QOL subscales, with the greatest in parental stress, and sustained through one year. CONCLUSIONS: BMP results in significant and sustained improvement in FI and QOL for patients and caregivers.

Evaluating associations between fitspiration and thinspiration content on Instagram and disordered-eating behaviors using ecological momentary assessment: A registered report.

INTRODUCTION: Greater use of appearance-focused social media, such as Instagram, is associated with increased body dissatisfaction and eating disorder (ED) symptoms; however, questions remain about the mechanism connecting social media use to disordered-eating behaviors (DEBs). The proposed study evaluates how and for whom exposure to fitspiration or thinspiration on Instagram is associated with DEBs. METHODS: We will evaluate a hypothesized pathway from Instagram use to disordered-eating mediated by negative affect. We will test how individual differences in internalized weight stigma, trait self-esteem, and trait self-comparison moderate the pathway from social media use to negative affect. We will recruit 175 undergraduate women who report engaging in DEBs on average at least once per week over the past 3 months. Participants will complete a 7-day ecological momentary assessment protocol, during which they will report their Instagram use, affect, and engagement in DEBs. RESULTS: Multi-level modeling will be used to assess moderated mediation. Results from this study will provide increased specificity about how Instagram usage is linked to eating pathology and who may be most vulnerable to experiencing distress. DISCUSSION: Information about negative affect from Instagram and engagement in DEBs could contribute to the development of Just-In-Time Interventions for problematic social media use.

Adaptive mHealth Intervention for Adolescent Physical Activity Promotion.

OBJECTIVE: The present nonrandomized controlled trial aimed to evaluate feasibility, acceptability, and preliminary efficacy of a tailored text message intervention for increasing adolescent physical activity, as compared with passive monitoring. METHODS: Forty adolescents (13-18 years old) received either a tailored text messaging intervention (Network Underwritten Dynamic Goals Engine [NUDGE]; N = 20), or participated in an attention-control condition (N = 20), for 20 days. Physical activity was measured for all participants via continuous accelerometry. Frequency analyses were conducted on program usage and satisfaction ratings to evaluate feasibility and acceptability, and multilevel models were used to evaluate the efficacy hypotheses. RESULTS: The vast majority of participants (90%) reported being very or mostly satisfied with the NUDGE program and rated their enjoyment as above average. The intervention group was estimated to spend an average of 20.84 more minutes per day in moderate-to-vigorous physical activity relative to the attention-control group (ß = 20.84, SE = 8.19). Exploratory analyses revealed that the intervention group also engaged in 82 fewer minutes of sedentary time per day on average, although this effect was not significant due to the large variability in sedentary time (ß = -81.98, SE = 46.86). CONCLUSIONS: The NUDGE tailored text messaging intervention was feasible, acceptable, and efficacious in increasing physical activity in this sample. Findings warrant additional evaluation of NUDGE as both a standalone physical activity intervention or as part of a multicomponent package.

Individual Differences in the Relationship Between Pain Fear, Avoidance, and Pain Severity in a Chronic Abdominal Pain Sample and the Moderating Effect of Child Age.

BACKGROUND/PURPOSE: Most studies examining the components of the fear-avoidance model have examined processes at the group level. The current study used ecological momentary assessments to: (a) investigate the group and intraindividual relationships between pain fear, avoidance, and pain severity, (b) identify any heterogeneity between these relationships, and (c) explore the role of moderators to explain such heterogeneity. METHODS: Seventy-one pediatric patients with chronic abdominal pain (M = 13.34 years, standard deviation = 2.67 years) reported pain fear, avoidance, and pain severity four times per day over 14 days. RESULTS: Results indicated significant individual differences in the relationship between pain fear and pain avoidance predicting pain severity. Child age helped explain the heterogeneity in the relationships between pain avoidance and pain severity such that older children had a stronger and more positive relationship between these variables. The random effect between pain fear and pain severity also indicated a moderator trend of child age such that older children were likely to have a stronger and more positive relationship. CONCLUSIONS: The present study extends the fear-avoidance model by highlighting the importance of identifying potential individual differences when examining pain fear, avoidance, and pain severity. Furthermore, the current study suggests that child development should be considered in the model. However, future randomized control designs are necessary to explore the causal relationships between pain fear and avoidance on pain severity and potential developmental differences.

Differences in adolescent activity and dietary behaviors across home, school, and other locations warrant location-specific intervention approaches.

BACKGROUND: Investigation of physical activity and dietary behaviors across locations can inform "setting-specific" health behavior interventions and improve understanding of contextual vulnerabilities to poor health. This study examined how physical activity, sedentary time, and dietary behaviors differed across home, school, and other locations in young adolescents. METHODS: Participants were adolescents aged 12-16 years from the Baltimore-Washington, DC and the Seattle areas from a larger cross-sectional study. Participants (n = 472) wore an accelerometer and Global Positioning Systems (GPS) tracker (Mean days = 5.12, SD = 1.62) to collect location-based physical activity and sedentary data. Participants (n = 789) completed 24-h dietary recalls to assess dietary behaviors and eating locations. Spatial analyses were performed to classify daily physical activity, sedentary time patterns, and dietary behaviors by location, categorized as home, school, and "other" locations. RESULTS: Adolescents were least physically active at home (2.5 min/hour of wear time) and school (2.9 min/hour of wear time) compared to "other" locations (5.9 min/hour of wear time). Participants spent a slightly greater proportion of wear time in sedentary time when at school (41 min/hour of wear time) than at home (39 min/hour of wear time), and time in bouts lasting ≥30 min (10 min/hour of wear time) and mean sedentary bout duration (5 min) were highest at school. About 61% of daily energy intake occurred at home, 25% at school, and 14% at "other" locations. Proportionately to energy intake, daily added sugar intake (5 g/100 kcal), fruits and vegetables (0.16 servings/100 kcal), high calorie beverages (0.09 beverages/100 kcal), whole grains (0.04 servings/100 kcal), grams of fiber (0.65 g/100 kcal), and calories of fat (33 kcal/100 kcal) and saturated fat (12 kcal/100 kcal) consumed were nutritionally least favorable at "other" locations. Daily sweet and savory snacks consumed was highest at school (0.14 snacks/100 kcal). CONCLUSIONS: Adolescents' health behaviors differed based on the location/environment they were in. Although dietary behaviors were generally more favorable in the home and school locations, physical activity was generally low and sedentary time was higher in these locations. Health behavior interventions that address the multiple locations in which adolescents spend time and use location-specific behavior change strategies should be explored to optimize health behaviors in each location.

Developing Empirical Decision Points to Improve the Timing of Adaptive Digital Health Physical Activity Interventions in Youth: Survival Analysis.

BACKGROUND: Current digital health interventions primarily use interventionist-defined rules to guide the timing of intervention delivery. As new temporally dense data sets become available, it is possible to make decisions about the intervention timing empirically. OBJECTIVE: This study aimed to explore the timing of physical activity among youth to inform decision points (eg, timing of support) for future digital physical activity interventions. METHODS: This study comprised 113 adolescents aged between 13 and 18 years (mean age 14.64, SD 1.48 years) who wore an accelerometer for 20 days. Multilevel survival analyses were used to estimate the most likely time of day (via odds ratios and hazard probabilities) when adolescents accumulated their average physical activity. The interacting effects of physical activity timing and moderating variables were calculated by entering predictors, such as gender, sports participation, and school day, into the model as main effects and tested for interactions with the time of day to determine conditional main effects of these predictors. RESULTS: On average, the likelihood that a participant would accumulate a typical amount of moderate-to-vigorous physical activity increased and peaked between 6 PM and 8 PM before decreasing sharply after 9 PM. Hazard and survival probabilities suggest that optimal decision points for digital physical activity programs could occur between 5 PM and 8 PM. CONCLUSIONS: Overall, the findings of this study support the idea that the timing of physical activity can be empirically identified and that these markers may be useful as intervention triggers.