Passive sensing of smartphone use, physical activity and sedentary behavior among adolescents and young adults during the COVID-19 pandemic.

The research that links excessive screen time to adverse health outcomes is based on self-reported screen use. Few studies have documented how passively-sensed smartphone and app use relate to health behaviors like activity and sitting. Furthermore, they have not considered that daily fluctuations in smartphone/app use may have different relationships to these behaviors than a person's usual smartphone/app use. This study evaluated whether physical activity or sedentary (sitting) behavior are associated with either smartphone screen time or specific smartphone app use by adolescents and young adults during the COVID-19 pandemic. Adolescents and young adults aged 13-29 years wore activPAL4 micro activity monitors while their smartphones logged daily screen time and app use durations for nine days. Data were collected in 2020-2021 and analyzed in 2022-2023. Participants (N = 125) had a mean (SD) age of 19.7 (4.3) years. Participants' usual smartphone screen time was negatively associated with daily step counts. Daily deviations in smartphone screen time were negatively associated with daily step counts and moderate-vigorous physical activity durations. Time spent on Instagram, YouTube and, to a lesser extent, TikTok were linked with reduced activity levels. Daily sedentary behavior was not associated with usual or daily screen time. Interventions to promote physical activity during the transition into adulthood may benefit from limiting excessive smartphone screen time. Specific intervention targets could include limiting use of apps with infinite scrolling feeds algorithmically tuned to maintain user engagement, such as Instagram, YouTube and TikTok.

Behavioral, psychological, and environmental predictors of weight regain in a group of successful weight losers in a widely available weight-management program.

OBJECTIVE: The aim of this study was to identify predictors of weight regain and continued weight maintenance among individuals already successful at long-term weight loss in a widely available weight-management program. METHODS: Participants were 2843 weight-loss maintainers in WeightWatchers who had maintained weight loss ≥9.1 kg for ≥1 year (average 25.5 kg for 3.5 years; BMI = 26.7 kg/m2 ). Validated behavioral, psychosocial, and home environmental questionnaires were administered at study entry and 1 year later. Discriminant analysis identified variables that discriminated gainers (≥2.3-kg gain) from maintainers (±2.3-kg change). RESULTS: Over the 1 year of follow-up, 43% were gainers (mean [SD], 7.2 [5.4] kg), and 57% were maintainers (0.4 [1.2] kg). Compared with maintainers, gainers were younger and had higher initial weight, more recent weight losses, and larger initial weight losses. Standardized canonical coefficients indicated that the 1-year changes that most discriminated gainers from maintainers were greater decreases in the ability to accept uncomfortable food cravings, urges, and desires to overeat (0.232); self-monitoring (0.166); body image (0.363); and body satisfaction (0.194) and greater increases in disinhibition (0.309) and bodily pain (0.147). The canonical correlation was 0.505 (p < 0.001). CONCLUSIONS: Future interventions to prevent regain should consider targeting overeating in response to internal and external food cues and declines in self-monitoring and body image.

Motivational Message Framing Effects on Physical Activity Dynamics in a Digital Messaging Intervention: Secondary Analysis.

BACKGROUND: Digital smartphone messaging can be used to promote physical activity to large populations with limited cost. It is not clear which psychological constructs should be targeted by digital messages to promote physical activity. This gap presents a challenge for developing optimal content for digital messaging interventions. OBJECTIVE: The aim of this study is to compare affectively framed and social cognitively framed messages on subsequent changes in physical activity using dynamical modeling techniques. METHODS: We conducted a secondary analysis of data collected from a digital messaging intervention in insufficiently active young adults (18-29 years) recruited between April 2019 and July 2020 who wore a Fitbit smartwatch for 6 months. Participants received 0 to 6 messages at random per day across the intervention period. Messages were drawn from 3 content libraries: affectively framed, social cognitively framed, or inspirational quotes. Person-specific dynamical models were identified, and model features of impulse response and cumulative step response were extracted for comparison. Two-way repeated-measures ANOVAs evaluated the main effects and interaction of message type and day type on model features. This early-phase work with novel dynamic features may have been underpowered to detect differences between message types so results were interpreted descriptively. RESULTS: Messages (n=20,689) were paired with valid physical activity monitoring data from 45 participants for analysis. Received messages were distributed as 40% affective (8299/20,689 messages), 39% social-cognitive (8187/20,689 messages), and 20% inspirational quotes (4219/20,689 messages). There were no statistically significant main effects for message type when evaluating the steady state of step responses. Participants demonstrated heterogeneity in intervention response: some had their strongest responses to affectively framed messages, some had their strongest responses to social cognitively framed messages, and some had their strongest responses to the inspirational quote messages. CONCLUSIONS: No single type of digital message content universally promotes physical activity. Future work should evaluate the effects of multiple message types so that content can be continuously tuned based on person-specific responses to each message type.

Dose-response relations between the frequency of two types of momentary feedback prompts and daily physical activity.

OBJECTIVE: Self-monitoring and behavioral feedback are widely used to help people monitor progress toward daily physical activity goals. Little information exists about the optimal dosing parameters for these techniques or if they are interchangeable in digital physical activity interventions. This study used a within-person experimental design to evaluate associations between the frequency of two different prompt types (one for each technique) and daily physical activity. METHOD: Insufficiently active young adults were assigned monthly physical activity goals and wore smartwatches with activity trackers for 3 months. They received zero to six randomly selected and timed watch-based prompts each day, with individual prompts either providing behavioral feedback or prompting the participant to self-monitor. RESULTS: Physical activity increased significantly over the 3-month period (step counts d = 1.03; moderate-to-vigorous physical activity duration d = 0.99). Mixed linear models revealed that daily step counts were positively associated with the frequency of daily self-monitoring prompts up to approximately three prompts/day (d = 0.22) after which additional prompts provided minimal or reduced benefit. Daily step counts were not associated with the frequency of behavioral feedback prompts. Daily moderate-to-vigorous physical activity was not associated with the frequency of either prompt. CONCLUSIONS: Self-monitoring and behavioral feedback are not interchangeable behavior change techniques in digital physical activity interventions, and only self-monitoring prompts show signs of a dose-response association with physical activity volume. Activity trackers, such as smartwatches and mobile apps, should provide an option to replace behavioral feedback prompts with self-monitoring prompts to promote physical activity among insufficiently active young adults. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Wellness Achieved Through Changing Habits: A Randomized Controlled Trial of an Acceptance-Based Intervention for Adolescent Girls With Overweight or Obesity.

Background: Obesity prevalence among adolescent girls continues to rise. Acceptance-based therapy (ABT) is effective for weight loss in adults and feasible and acceptable for weight loss among adolescents. This pilot randomized controlled trial (RCT) assessed effectiveness of an adolescent-tailored ABT intervention on decreasing weight-related outcomes and improving psychological outcomes compared with enhanced care. Methods: In this 6-month, two-arm pilot RCT, participants were randomized to the ABT intervention or to enhanced care. The ABT intervention condition attended 15 virtual, 90-minute group sessions. The enhanced care comparison received 15 healthy lifestyle handouts and virtually met twice with a registered dietitian. The primary outcome assessed was change in BMI expressed as a percentage of the 95th percentile (%BMIp95). Results: Participants included 40 girls (ages 14-19) assigned to ABT (n = 20) or enhanced care (n = 20). A decrease in %BMIp95 was observed within the ABT intervention [d = -0.19, 95% confidence interval, CI: (-0.36 to -0.02)], however, not within the enhanced care comparison [d = -0.01, 95% CI: (-0.09 to 0.07)]. The ABT group showed slight changes in psychological flexibility [d = -0.34, 95% CI: (-0.62 to -0.06)] over enhanced care [d = -0.11, 95% CI: (-0.58 to 0.37)]. There was no significant intervention effect noted between groups. Conclusion: In this pilot RCT, the ABT intervention was as effective as enhanced care for weight loss. However, previous ABT studies occurred in person, and this study was conducted virtually due to COVID-19. Thus, future research investigating the potential effectiveness of ABT in-person among adolescents and optimization of virtual interventions is needed.

Physical Activity Dynamics During a Digital Messaging Intervention Changed After the Pandemic Declaration.

BACKGROUND: The COVID-19 pandemic adversely impacted physical activity, but little is known about how contextual changes following the pandemic declaration impacted either the dynamics of people's physical activity or their responses to micro-interventions for promoting physical activity. PURPOSE: This paper explored the effect of the COVID-19 pandemic on the dynamics of physical activity responses to digital message interventions. METHODS: Insufficiently-active young adults (18-29 years; N = 22) were recruited from November 2019 to January 2020 and wore a Fitbit smartwatch for 6 months. They received 0-6 messages/day via smartphone app notifications, timed and selected at random from three content libraries (Move More, Sit Less, and Inspirational Quotes). System identification techniques from control systems engineering were used to identify person-specific dynamical models of physical activity in response to messages before and after the pandemic declaration on March 13, 2020. RESULTS: Daily step counts decreased significantly following the pandemic declaration on weekdays (Cohen's d = -1.40) but not on weekends (d = -0.26). The mean overall speed of the response describing physical activity (dominant pole magnitude) did not change significantly on either weekdays (d = -0.18) or weekends (d = -0.21). In contrast, there was limited rank-order consistency in specific features of intervention responses from before to after the pandemic declaration. CONCLUSIONS: Generalizing models of behavioral dynamics across dramatically different environmental contexts (and participants) may lead to flawed decision rules for just-in-time physical activity interventions. Periodic model-based adaptations to person-specific decision rules (i.e., continuous tuning interventions) for digital messages are recommended when contexts change.

Physical inactivity is recognized as one of the major risk factors for cardiovascular disease, diabetes, and many cancers. Most American adults fail to achieve recommended levels of physical activity. Interventions to promote physical activity in young adults are needed to reduce long-term chronic disease risk. The COVID-19 pandemic declaration abruptly changed many individuals' environments and lifestyles. These contextual changes adversely impacted physical activity levels but little is known about how these changes specifically impacted the dynamics of people's physical activity or responses to micro-interventions for promoting physical activity. Using data collected from Fitbit smartwatches before and after the pandemic declaration, we applied tools from control systems engineering to develop person-specific dynamic models of physical activity responses to messaging interventions, and investigated how physical activity dynamics changed from before to after the pandemic declaration. Step counts decreased significantly on weekdays. The average speed of participants' responses to intervention messages did not change significantly, but intervention response dynamics had limited consistency from before to after the pandemic declaration. In short, participants changed how they responded to interventions after the pandemic declaration but the magnitude and patterns of change varied across participants. Person-specific, adaptive interventions can be useful for promoting physical activity when behavioral systems are stimulated to reorganize by external factors.

Assessment of Physical Activity and Healthy Eating Behaviors Among US Adults Receiving Bariatric Surgery.

Importance: Bariatric surgery effectively treats severe obesity and metabolic diseases. However, individual outcomes vary depending on sustainable lifestyle change. Little is known about lifestyle patterns after bariatric surgery among the US population. Objective: To compare the level of physical activity and eating behavior among postbariatric surgery patients, individuals eligible for surgery, and those with normal weight. Design, Setting, and Participants: A cross-sectional study using nationally representative survey data from National Health and Nutrition Examination Survey 2015-2018. Respondents included for analysis were age 18 years or older, and categorized by individuals with normal weight, individuals who received bariatric surgery, and individuals clinically eligible for bariatric surgery. Analyses were performed from February to October 2021. Main Outcomes and Measures: Self-reported measures were used to assess physical activity (moderate-to-vigorous physical activity [MVPA], sedentary activity, and whether PA guidelines were met) and eating behaviors (total energy intake and Healthy Eating Index [HEI]-2015 diet quality scores). Results: Of 4659 study participants (mean [SD] age, 46.1 [18.6] years; 2638 [weighted percentage, 58.8%] women; 1114 [weighted percentage, 12.7%] Black, 1570 [weighted percentage, 68.6%] White), 132 (3.7%) reported that they had undergone any bariatric surgery. Median (IQR) time since surgery was 7 (3-10) years. After propensity-score weighting, individuals who underwent bariatric surgery reported more time spent in MVPA than those eligible for surgery (147.9 min/wk vs 97.4 min/wk). Among respondents with normal weight, 45.6% (95% CI, 40.8% to 52.4%) reported meeting PA guidelines, almost 2 times higher than those in the bariatric surgery (23.1%; 95% CI, 13.8% to 32.4%) or in the surgery-eligible group (20.3%; 95% CI, 15.6% to 25.1%). Propensity-score weighted overall HEI was higher for individuals with normal weight (54.4; 95% CI, 53.0 to 55.9) than those who underwent bariatric surgery (50.0; 95% CI, 47.2 to 52.9) or were eligible for the surgery (48.0; 95% CI, 46.0 to 50.0). Across all HEI components, mean scores were similar between the bariatric surgery and surgery-eligible groups. Total energy intake was the lowest among those who underwent bariatric surgery (1746 kcal/d; 95% CI, 1554 to 1937 kcal/d), followed by those with normal weight (1943 kcal/d; 95% CI, 1873 to 2013 kcal/d) and those eligible for bariatric surgery (2040 kcal/d; 1953 to 2128 kcal/d). Conclusions and Relevance: In this cross-sectional study, individuals who underwent bariatric surgery had beneficial lifestyle patterns compared with those eligible for surgery; however, these improvements seemed suboptimal based on the current guidelines. Efforts are needed to incorporate benefits of physical activity and a healthy, balanced diet in postbariatric care.

The effects of experimentally manipulated social status and subjective social status on physical activity among Hispanic adolescents: An RCT.

BACKGROUND: Low objective socioeconomic status (SES) and subjective social status (SSS), one's perceived social rank, are associated with obesity. This association may be due, in part, to social status-related differences in energy expenditure. Experimental studies are needed to assess the extent to which SES and SSS relate to energy expenditure. OBJECTIVE: Assess the effects of experimentally manipulated social status and SSS on moderate-to-vigorous physical activity (MVPA) and sedentary behaviour. METHODS: One hundred thirty-three Hispanic adolescents aged 15-21 were randomized to a high or low social status position, facilitated through a rigged game of Monopoly™. SSS was assessed with MacArthur Scales. Post-manipulation 24-h MVPA and sedentary behaviour were assessed via accelerometry. Analyses were conducted with general linear regression models. RESULTS: Experimentally manipulated social status did not significantly affect the total time spent in MVPA or sedentary behaviour; however, identifying as low SSS was significantly associated with less MVPA (p = 0.0060; 18.76 min less). CONCLUSIONS: Tewnty-four-hour MVPA and sedentary behaviour are not affected by an acute experimental manipulation of social status. However, low SSS, independent of SES, was associated with clinically significant differences in MVPA. SSS may be a better predictor of MVPA than SES among Hispanic adolescents, potentially influencing obesity, and other health-related outcomes.

Adverse Childhood Experiences Are Associated with Cardiometabolic Risk among Hispanic American Adolescents.

OBJECTIVE: To assess the relationship between adverse childhood experiences (ACEs) and cardiometabolic risk among Hispanic adolescents. STUDY DESIGN: This cross-sectional study was conducted at an academic research center in Gainesville, Florida. Participants were locally recruited, and data were collected from June 2016 to July 2018. Participants (n = 133, 60.2% female) were healthy adolescents aged 15-21 years who self-identified as Hispanic, were born in the US, and had a body mass index (BMI) between ≥18.5 and ≤40 kg/m2. Primary outcomes were BMI, body fat percentage, waist circumference, and resting blood pressure. Associations between ACEs and cardiometabolic measures were assessed by multivariable logistic regression models, which controlled for sex, age, parental education, and food insecurity. Results were sex-stratified to assess potential variations. RESULTS: Reporting ≥4 ACEs (28.6%) was significantly associated with a greater BMI (P = .004), body fat percentage (P = .02), and diastolic blood pressure (P = .05) compared with reporting <4 ACEs. Female participants reporting ≥4 ACEs were significantly more likely to have a greater BMI (P = .04) and body fat percentage (P = .03) whereas male participants reporting ≥4 ACEs were significantly more likely to have a greater BMI (P = .04), systolic blood pressure (P = .03), and diastolic blood pressure (P = .03). CONCLUSIONS: Hispanic adolescent participants who experienced ≥4 ACEs were more likely to have elevated risk markers of obesity and cardiometabolic disease. Further research is needed to elucidate the physiological mechanisms driving these relationships.

Feasibility/acceptability of an acceptance-based therapy intervention for diverse adolescent girls with overweight/obesity.

BACKGROUND: Behavioral obesity interventions using an acceptance-based therapy (ABT) approach have demonstrated efficacy for adults, yet feasibility and acceptability of tailoring an ABT intervention for adolescents remains unknown. OBJECTIVE: This study assessed the feasibility and acceptability of an ABT healthy lifestyle intervention among diverse adolescent cisgender girls with overweight/obesity (OW/OB). METHODS: Adolescent cisgender girls aged 14-19 with a BMI of ≥85th percentile-for-sex-and-age were recruited for participation in a single-arm feasibility study. The primary outcomes were recruitment and retention while the secondary outcome was change in BMI Z-score over the 6-month intervention. Exploratory outcomes included obesity-related factors, health-related behaviors, and psychological factors. RESULTS: Recruitment goals were achieved; 13 adolescents (>60% racial/ethnic minorities) participated in the intervention, and 11 completed the intervention (85% retention). In completers (n = 11), a mean decrease in BMI Z-score of -0.15 (SD = 0.34, Cohen's d = -0.44) was observed. Improvements were also noted for change in percentage of 95th percentile (d = -0.35), percent body fat (d = -0.35), quality of life (d = 0.71), psychological flexibility (d = -0.86), and depression (d = -0.86). CONCLUSIONS: These preliminary findings suggest an ABT healthy lifestyle intervention tailored for adolescent cisgender girls with OW/OB may be an acceptable treatment that could lead to improvements in BMI Z-score, obesity-related measures, and psychological outcomes.

Psychological Resilience, Experimentally Manipulated Social Status, and Dietary Intake among Adolescents.

Relative to other racial/ethnic groups in the United States, Hispanic American (HA) youth have higher rates of overweight and obesity. Previous work suggests that low perceived social status (SS) promotes excess caloric intake and, thereby, development of obesity. Psychological resilience may play a role in reducing adverse eating behaviors and risk for obesity. The objective of this study was to investigate whether resilience (as measured by the Connor Davidson Resilience Scale) interacts with experimentally manipulated SS to affect dietary intake among HA adolescents (n = 132). Using a rigged game of Monopoly (Hasbro, Inc.), participants were randomized to a high or low SS condition. Following the Monopoly game, participants consumed an ad libitum lunch and their dietary intake was assessed. There was a significant interaction between resilience and experimentally manipulated SS for total energy intake (p = 0.006), percent energy needs consumed (p = 0.005), and sugar intake (p = 0.004). For the high SS condition, for each increase in resilience score, total energy intake decreased by 7.165 ± 2.866 kcal (p = 0.014) and percent energy needs consumed decreased by 0.394 ± 0.153 (p = 0.011). In the low SS condition, sugar intake increased by 0.621 ± 0.240 g for each increase in resilience score (p = 0.011). After correction for multiple comparisons, the aforementioned interactions, but not simple slopes, were statistically significant.

Behavioral Weight Loss Intervention Preferences of Adolescents with Overweight/Obesity.

Background: Behavioral lifestyle interventions are the foundation of adolescent obesity treatment. Tailoring an intervention using adolescent stakeholder engagement during the development process could improve intervention effectiveness. Methods: Adolescents with overweight/obesity ages 14-19 (n = 41) participated in 11 sex-specific focus groups (girls = 6, boys = 5) and were asked their preferences regarding who should lead the intervention and be involved, what the messaging of the program should be, how to make the program engaging and maintain participation, and how to best measure nutrition intake and activity. Transcripts were coded and analyzed for emergent themes. Results: Mean age was 16.0 ± 1.8 years and participants were racially/ethnically diverse. Adolescents preferred interventions that avoid a focus on "weight loss," and instead emphasize "healthy lifestyle," which represents a more comprehensive goal of targeting physical and mental well-being. Most participants indicated preferences for a relatable instructor with prior weight loss experience. Both sexes preferred optional parental involvement, as some parents were described as helpful, while others were perceived as a hindrance to success. Boys and girls identified incentives, engaging activities, and electronic communication as core components for engagement and retention, with girls emphasizing socialization and building relationships. Sex differences in preferences were observed. Girls had more concerns about intervention participation and preferred interventions to be sex stratified. Conclusions: Behavioral interventions to treat adolescent obesity should focus messaging/content on healthy lifestyles, rather than weight loss, and be sex stratified. Development and implementation of future behavioral interventions for adolescent obesity should consider tailoring to adolescent preferences when possible to improve feasibility, acceptability, and effectiveness.

Experimentally Manipulated Low Social Status and Food Insecurity Alter Eating Behavior Among Adolescents: A Randomized Controlled Trial.

OBJECTIVE: This randomized trial experimentally manipulated social status to assess effects on acute eating behavior and 24-hour energy balance. METHODS: Participants (n = 133 Hispanics; age 15-21 years; 60.2% females) were randomized to low social status ("LOW") or high social status ("HIGH") conditions in a rigged game of Monopoly (Hasbro, Inc.). Acute energy intake in a lunchtime meal was measured by food scales. Twenty-four-hour energy balance was assessed via summation of resting metabolic rate (metabolic cart), physical activity energy expenditure (accelerometer), thermic effect of food, and subtraction of twenty-four-hour energy intake (food diary). RESULTS: In the total sample, no significant differences were observed by study condition at lunchtime. LOW females consumed a greater percent of lunchtime daily energy needs (37.5%) relative to HIGH females (34.3%); however, this difference was not statistically significant (P = 0.291). In males, however, LOW consumed significantly less (36.5%) of their daily energy needs relative to HIGH males (45.8%; P = 0.001). For 24-hour energy balance, sex differences were nearly significant (P = 0.057; LOW females: surplus +200 kcal; HIGH males: surplus +445 kcal). Food-insecure individuals consumed a nearly significant greater lunchtime percent daily energy than those with food security (40.7% vs. 36.3%; P = 0.0797). CONCLUSIONS: The data demonstrate differential acute and 24-hour eating behavior responses between Hispanic male and female adolescents in experimentally manipulated conditions of low social status.

The Influence of Socioeconomic Status on Snacking and Weight among Adolescents: A Scoping Review.

Eating behaviors, including unhealthy snacking or excessive snacking leading to excess calorie consumption, may contribute to obesity among adolescents. Socioeconomic status (SES) also significantly influences eating behaviors, and low SES is associated with increased risk for obesity. However, little is known regarding the relationship between snacking behavior and SES among adolescents and how this may contribute to obesity-related outcomes. The primary objective of this scoping review was to review the literature to assess and characterize the relationship between SES and snacking in adolescents. The secondary objective was to assess weight-related outcomes and their relation to snacking habits. Included articles were published between January 2000 and May 2019; written in English, Portuguese, or Spanish; and focused on adolescents (13-17 years). In total, 14 bibliographic databases were searched, and seven studies met the inclusion criteria. Preliminary evidence from the seven included studies suggests a weak but potential link between SES and snacking. Additionally, these dietary patterns seemed to differ by sex and income type of country. Finally, only three of the included studies addressed weight-related outcomes, but the overall available evidence suggests that snacking does not significantly affect weight-related outcomes. Due to the small number of included studies, results should be interpreted with caution.

Teaching Type 1 Diabetes: Creating Stakeholder Engagement in Biomedical Careers Through Undergraduate Research Curriculum.

Undergraduate students living with chronic diseases attending universities where major biomedical research takes place are critical stakeholders in these programs, yet they often remain sequestered from them. A directed research curriculum about Type 1 Diabetes (T1D) was developed to better engage undergraduate students with personal connections to the disease in a large medical university setting world renowned for its research in this area. The course had the following student learning outcomes: (1) gain knowledge of major T1D research programs; (2) exposure to careers in T1D research and clinical care; and (3) recognize bioethical issues in T1D research.

Social Status and Adolescent Physical Activity: Expanding the Insurance Hypothesis to Incorporate Energy Expenditure.

Low social status (SS) is a determinant of poor health status and is associated with increased disease burden. Obesity affects 20.6% of American adolescents, most of whom are from low-SS families. Contributors to the development of obesity among adolescents include sedentary behavior and low levels of physical activity. Environmental determinants-infrastructure, policy, and social relationships-influence engagement in physical activity and are affected by SS. Significant declines in physical activity have been documented during adolescence, and adolescents of low SS engage in significantly less physical activity per week than those with high SS. This article briefly reviews the literature on the relationship between SS and physical activity in adolescents and introduces a proposed biological mechanism that may explain that relationship. Characterizing the effects that SS can have on physical activity may help tailor clinical interventions and public health campaigns seeking to improve adolescent physical activity and weight management, thus increasing their effectiveness. This may be particularly beneficial for underserved populations.

Efficacy and Effectiveness of Mobile Health Technologies for Facilitating Physical Activity in Adolescents: Scoping Review.

BACKGROUND: Increasing physical activity (PA) levels in adolescents aged 12 to 18 years is associated with prevention of unhealthy weight gain and improvement in cardiovascular fitness. The widespread availability of mobile health (mHealth) and wearable devices offers self-monitoring and motivational features for increasing PA levels and improving adherence to exercise programs. OBJECTIVE: The aim of this scoping review was to identify the efficacy or effectiveness of mHealth intervention strategies for facilitating PA among adolescents aged 12 to 18 years. METHODS: We conducted a systematic search for peer-reviewed studies published between 2008 and 2018 in the following electronic databases: PubMed, Google Scholar, PsychINFO, or SportDiscus. The search terms used included mHealth or "mobile health" or apps, "physical activity" or exercise, children or adolescents or teens or "young adults" or kids, and efficacy or effectiveness. Articles published outside of the date range (July 2008 to October 2018) and non-English articles were removed before abstract review. Three reviewers assessed all abstracts against the inclusion and exclusion criteria. Any uncertainties or differences in opinion were discussed as a group. The inclusion criteria were that the studies should (1) have an mHealth component, (2) target participants aged between 12 and 18 years, (3) have results on efficacy or effectiveness, and (4) assess PA-related outcomes. Reviews, abstracts only, protocols without results, and short message service text messaging-only interventions were excluded. We also extracted potentially relevant papers from reviews. At least 2 reviewers examined all full articles for fit with the criteria and extracted data for analysis. Data extracted from selected studies included study population, study type, components of PA intervention, and PA outcome results. RESULTS: Overall, 126 articles were initially identified. Reviewers pulled 18 additional articles from excluded review papers. Only 18 articles were passed onto full review, and 16 were kept for analysis. The included studies differed in the sizes of the study populations (11-607 participants), locations of the study sites (7 countries), study setting, and study design. Overall, 5 mHealth intervention categories were identified: website, website+wearable, app, wearable+app, and website+wearable+app. The most common measures reported were subjective weekly PA (4/13) and objective daily moderate-to-vigorous PA (5/13) of the 19 different PA outcomes assessed. Furthermore, 5 of 13 studies with a control or comparison group showed a significant improvement in PA outcomes between the intervention group and the control or comparison group. Of those 5 studies, 3 permitted isolation of mHealth intervention components in the analysis. CONCLUSIONS: PA outcomes for adolescents improved over time through mHealth intervention use; however, the lack of consistency in chosen PA outcome measures, paucity of significant outcomes via between-group analyses, and the various study designs that prevent separating the effects of intervention components calls into question their true effect.

Mobile Device Accuracy for Step Counting Across Age Groups.

BACKGROUND: Only one in five American meets the physical activity recommendations of the Department of Health and Human Services. The proliferation of wearable devices and smartphones for physical activity tracking has led to an increasing number of interventions designed to facilitate regular physical activity, in particular to address the obesity epidemic, but also for cardiovascular disease patients, cancer survivors, and older adults. However, the inconsistent findings pertaining to the accuracy of wearable devices for step counting needs to be addressed, as well as factors known to affect gait (and thus potentially impact accuracy) such as age, body mass index (BMI), or leading arm. OBJECTIVE: We aim to assess the accuracy of recent mobile devices for counting steps, across three different age groups. METHODS: We recruited 60 participants in three age groups: 18-39 years, 40-64 years, and 65-84 years, who completed two separate 1000 step walks on a treadmill at a self-selected speed between 2 and 3 miles per hour. We tested two smartphones attached on each side of the waist, and five wrist-based devices worn on both wrists (2 devices on one wrist and 3 devices on the other), as well as the Actigraph wGT3X-BT, and swapped sides between each walk. All devices were swapped dominant-to-nondominant side and vice-versa between the two 1000 step walks. The number of steps was recorded with a tally counter. Age, sex, height, weight, and dominant hand were self-reported by each participant. RESULTS: Among the 60 participants, 36 were female (60%) and 54 were right-handed (90%). Median age was 53 years (min=19, max=83), median BMI was 24.1 (min=18.4, max=39.6). There was no significant difference in left- and right-hand step counts by device. Our analyses show that the Fitbit Surge significantly undercounted steps across all age groups. Samsung Gear S2 significantly undercounted steps only for participants among the 40-64 year age group. Finally, the Nexus 6P significantly undercounted steps for the group ranging from 65-84 years. CONCLUSIONS: Our analysis shows that apart from the Fitbit Surge, most of the recent mobile devices we tested do not overcount or undercount steps in the 18-39-year-old age group, however some devices undercount steps in older age groups. This finding suggests that accuracy in step counting may be an issue with some popular wearable devices, and that age may be a factor in undercounting. These results are particularly important for clinical interventions using such devices and other activity trackers, in particular to balance energy requirements with energy expenditure in the context of a weight loss intervention program.