Background: Although mobile health (mHealth) interventions have demonstrated effectiveness in modifying 1 or2 health-risk behaviors at a time, there is a knowledge gap regarding the effects of stand-alone mHealth interventions on multiple health risk behaviors. Objective: This study aimed to estimate the 2-and 4-month effectiveness of an mHealth intervention (LIFE4YOUth) targeting alcohol consumption, diet, physical activity, and smoking among Swedish high school students, compared with a waiting-list control condition. Methods: A 2-arm parallel group, single-blind randomized controlled trial (1:1) was conducted from September 2020 to June 2023. Eligibility criteria included nonadherenceto guidelines related to the primary outcomes, such as weekly alcohol consumption (standard drinks), monthly frequency of heavy episodic drinking (ie, >= 4 standard drinks), daily intake of fruit and vegetables (100-g portions), weekly consumption of sugary drinks (33-cL servings), weekly duration of moderateto vigorous physical activity (minutes), and 4-week point prevalence of smoking abstinence. The intervention group had 16 weeks of access to LIFE4YOUth, a fully automated intervention including recurring screening, text message services, and a web-based dashboard. Intention-to-treat analysis was conducted on available and imputed 2-and 4-month self-reported data from participants at risk for each outcome respectively, at baseline. Effects were estimated using multilevel models with adaptive intercepts (per individual) and time by group interactions, adjusted for baseline age, sex, household economy, and self-perceived importance, confidence, and know-how to change behaviors. Bayesian inference with standard (half-)normal priors and null-hypothesis testing was used to estimate the parameters of statistical models. Results: In total, 756 students (aged 15-20, mean 17.1, SD 1.2 years; 69%, 520/756 females; 31%, 236/756 males) from high schools across Sweden participated in the trial. Follow-up surveys were completed by 71% (539/756) of participants at 2 months and 57% (431/756) of participants at 4 months. Most participants in the intervention group (219/377, 58%) engaged with the intervention at least once. At 2 months, results indicated positive effects in the intervention group, with complete case data indicating median between-group differences in fruit and vegetable consumption (0.32 portions per day, 95% CI 0.13-0.52), physical activity (50 minutes per week, 95% CI-0.2 to 99.7), and incidence rate ratio for heavy episodic drinking (0.77, 95% CI 0.55-1.07). The odds ratio for smoking abstinence (1.09, 95% CI 0.34-3.64), incidence rate ratio for weekly alcohol consumption (0.69, 95% CI 0.27-1.83), and the number of sugary drinks consumed weekly (0.89, 95% CI 0.73-1.1) indicated inconclusive evidence for effects due to uncertainty in the estimates. At 4 months, a remaining effect was observed on physical activity only. Conclusions:Although underpowered, our findings suggest modest short-term effects of the LIFE4YOUth intervention, primarily on physical activity and fruit and vegetable consumption. Our results provide inconclusive evidence regarding weekly alcohol consumption and smoking abstinence.

Precision nutrition is a vibrant and rapidly evolving field of scientific research and innovation with the potential to deliver health, societal and economic benefits by improving healthcare delivery and policies. Advances in deep phenotyping technologies, digital tools and artificial intelligence have made possible early proof-of-concept research that expands the understanding of within- and between-person variability in responses to diet. These studies illustrate the promise of precision nutrition to complement the traditional 'one size fits all' dietary guidelines, which, while considering broad life-stage and disease-specific nutritional requirements, often lack the granularity to account fully for individual variations in nutritional needs and dietary responses. Despite these developments, however, considerable challenges remain before precision nutrition can be implemented on a broader scale. This Review examines the current state of precision nutrition research, with a focus on its application to reducing the incidence and burden of cardiometabolic diseases. We critically examine the evidence base, explore the potential benefits and discuss the challenges and opportunities ahead.

Background: Digital interventions are effective in promoting healthy behaviors and are recognized as one of many strategies for achieving healthier populations. These interventions often include goal-setting, but the practical application and fidelity of goal setting, especially when targeting multiple health behaviors, remain underexplored. In a factorial randomized trial, we included goal-setting as one of six behavior change components in the digital intervention "Buddy," targeting university and college students' alcohol, diet, physical activity, and smoking behaviors. However, we found no strong and consistent evidence of an effect of goal-setting alone on any of the outcomes, highlighting the need to investigate how participants used this component.

Objective: This case study of Buddy aimed to gain insight into participants' interactions with the goal-setting component. Specific objectives were to identify the characteristics of participants who used this component and to analyze participants' self-authored content.

Methods: This study combined fidelity and effectiveness findings and involved 1704 participants from 18 universities and colleges in Sweden. Self-authored goals and challenges were analyzed using summative content analysis. Logistic and negative binomial regression analyses were conducted to estimate the odds of setting a goal, selecting or self-authoring a challenge, to estimate the odds of setting a goal with respect to a specific behavior, and to estimate the frequency of selecting or self-authoring different behavioral challenges.

Results: Of the 850 participants given access to the goal setting and challenges component, 427 (50%) set at least one goal and 403 (47%) selected or self-authored at least one challenge. A total of 607 goals were set, with most participants setting one goal (336/427, 79%). Goals primarily targeted physical activity (n=302), dietary behavior (n=140), and multiple health behaviors (n=53), typically combining physical activity with diet, alcohol, smoking, or sleep. Other goals included study performance, mental health, sleep, and mobile phone use (n=73). Fewer goals concerned alcohol (n=19) or tobacco (n=17). Participants selected 1506 challenges from 41 premade challenges, with dietary behavior challenges being most popular (667/1506, 44%). An additional 170 challenges were self-authored. Participants’ baseline characteristics were associated with the odds of setting goals targeting specific behaviors and the frequency of selecting or self-authoring challenges targeting specific behaviors.

Conclusions: Our analyses suggest that, while goal-setting is theoretically grounded, and participants used Buddy in ways that suited their personal needs, this did not translate to measurable behavior change in the study population. The self-authored content showed how participants used the component and provided insights into how they articulate behavior change in terms of personal goals, challenges, strategies for action, motivation plans, and rewards. Future research should explore the conditions under which goal-setting may be more or less effective, to better understand its nuances and potential benefits.

Trial Registration: The UK's Clinical Study Registry ISRCTN23310640; https://www.isrctn.com/ISRCTN23310640

Background Little is known about the relationship of physical activity (PA) and fitness with cardiometabolic risk among rural adolescents in low- and middle-income countries. Thus, we examined the associations of PA and fitness with selected cardiometabolic indicators along with potential gender-based differences in a birth cohort of rural adolescents from southeast Bangladesh.Methods We utilized data from the 15-year follow-up of Maternal and Infant Nutrition Interventions in Matlab (MINIMat) cohort (n = 2253). Wrist-worn ActiGraph wGT3x-BT accelerometers were used to estimate sedentary time (ST) and PA. Fitness was assessed using: handgrip strength, standing long jump, and Chester Step Test. Anthropometric parameters, systolic blood pressure (SBP), and fasting lipid, insulin and glucose levels were measured. We calculated insulin resistance using the Homeostasis Model Assessment equation (HOMA-IR). Linear regression and isotemporal substitution models were fitted.Results The adolescents spent 64 min/day (inter-quartile range: 50-81) in moderate-to-vigorous physical activity (MVPA). A 10-minute-per-day higher vigorous PA (VPA) was associated with: 4.9% (95% confidence interval (CI): 2.9-6.8%) lower waist circumference (WC), 3.2 mmHg (95% CI: 1.5-4.8) lower SBP, 10.4% (95% CI: 2.9-17.3%) lower TG, and 24.4% (95% CI: 11.3-34.9%) lower HOMA-IR. MVPA showed similar associations of notably smaller magnitude. Except for WC, the associations were more pronounced among the boys. Substituting ST with VPA of equal duration was associated with lower WC, SBP, triglyceride and HOMA-IR. Grip strength was favorably associated with all indicators, displaying considerably large effect sizes.Conclusion Our findings indicated beneficial roles of PA- particularly VPA- and muscular fitness in shaping cardiometabolic profile in mid-adolescence. VPA and grip strength may represent potential targets for preventive strategies tailored to adolescents in resource-limited settings.

ObjectiveThe objective of this study was to examine the chronic effects of a 20-week exercise training program on device-assessed sleep and sleep-disordered breathing; and to determine whether participating in a session of the exercise program had effects on device-assessed sleep the subsequent night in children with overweight/obesity.MethodsA randomized clinical trial was conducted from November 2014 to June 2016. A total of 109 children (age 8-11 years) with overweight/obesity were randomized into an exercise training or control group. The exercise program included aerobic and resistance training 3 to 5 days/week. The control group participants continued their usual lifestyle. Device-assessed sleep outcomes were measured using wrist-worn actigraphy at baseline, in the middle of the exercise program (10th week), and at postintervention for seven consecutive days (24 h/day), and sleep-disordered breathing was measured via the Pediatric Sleep Questionnaire.ResultsThe exercise training program had a statistically significant effect on wake after sleep onset time (-10.8 min/day, -0.5 SDs, p = 0.040). No other chronic or acute effects (i.e., the subsequent night of attending a session of the exercise training program) were observed on the remaining sleep outcomes.ConclusionsA 20-week exercise training program reduced wake after sleep onset time in children with overweight/obesity. Future randomized trials that include a sample of children with poor sleep health at baseline are needed to better appreciate the role of exercise in sleep health.

BackgroundThere is evidence for a link between hyperactivity and obesity, especially among older children. Both conditions seem to be multifactorial in origin and hypotheses of common underlying issues, such as emotional dysregulation, have been suggested. However, studies of the co-occurrence of the two conditions in younger age groups have been inconclusive.ObjectivesWe aimed to study the longitudinal associations of psychological strengths and difficulties at 4 years of age with health behaviours, body composition, physical fitness, and cardiovascular disease (CVD) risk factors 5 years later.MethodsParents of 226 4-year-old children filled out the Strengths and Difficulties Questionnaire (SDQ). At 9 years of age, we assessed health behaviours, physical fitness, body composition, and CVD risk factors. Associations were examined with linear regression models that were adjusted for sex, age of the child at 9, and maternal education.ResultsIn the adjusted models, hyperactivity at 4 was associated with higher fat-free mass (beta = 0.18, p = 0.007) and lower levels of sedentary behaviour (beta -0.14, p = 0.043) at 9 years. Furthermore, greater emotional problems at 4 were associated with lower intake of fruit and vegetables (beta -0.14, p = 0.038) at 9 years. However, there were no statistically significant associations between psychological difficulties and fat-mass index.ConclusionsOur novel data provide no evidence of an association between hyperactivity in preschool age and obesity or obesity-related behaviours in school age. Future studies examining how psychological factors relate to obesity development should consider a developmental perspective.

Introduction Unhealthy lifestyle behaviors such as unhealthy diets, low physical activity levels, smoking, and harmful alcohol consumption are common in student populations, which constitute a large group of young adults. As unhealthy lifestyle behaviors are associated with future disease and premature mortality, most commonly from cardiovascular disease and cancers, it is from a public health perspective important to understand such behaviors in young adult populations. The objective of this study was to investigate university students experiences of health, health-related behaviors, and the barriers and facilitators for behavior change in terms of health promotion in everyday life. Materials and methods This qualitative study was conducted at a middle-sized university in Sweden. Students represented different faculties and were recruited via non-probability convenience sampling using means such as the snowball technique and social media. The 21 interviews with 24 students, individually or in groups, were transcribed verbatim prior to a qualitative analysis inspired by phenomenological hermeneutics. Results Our interviews showed that university student life is associated with new health-related challenges, for example study-related stress and procrastination implies a lack of energy to engage in healthy routines such as physical activity, and a limited budget affects food choices. While adapting to a new context, students explore personal strategies such as taking on changes in manageable steps, seeking social support, and avoiding disturbances to maintaining health and quality of life. Conclusions Experiences of health while becoming and being a university student can be described as a transition-a balancing act of walking a slack line-during which students seek to manage a healthy balance. In the past, interventions have to some extent been designed to address university students behaviors; however, our study aids an understanding of their needs. Future interventions should highlight the transitions they are experiencing and the challenges of student life.

Purpose The relation between diet and maternal mental health during pregnancy might be relevant to prevent adverse materno-foetal outcomes. This study examined the association of Mediterranean diet (MD) adherence and MD components with mental health during pregnancy. Methods This secondary analysis of the GESTAFIT trial included longitudinal data from 152 pregnant women. Dietary habits were assessed with a food frequency questionnaire, and MD adherence was derived from it using the Mediterranean Food pattern. Psychological ill-being (i.e., negative affect, anxiety, and depression) and well-being (i.e., emotional intelligence, resilience, positive affect) were assessed with the Spanish version of well-established self-reported questionnaires. Cross-sectional (16th gestational week [g.w.]) and longitudinal associations (34th g.w.) between MD and mental health were studied using linear regression models. Results A greater MD adherence was inversely associated with negative affect and anxiety; and positively associated with emotional regulation, resilience and positive affect at the 16th and 34th g.w. (|beta| ranging from 0.179 to 0.325, all p < 0.05). Additionally, a higher intake of whole grain cereals, fruits, vegetables, fish, olive oil and nuts, and a lower intake of red meat and subproducts and sweets were associated with lower negative affect, anxiety, depression and higher emotional regulation, resilience and positive affect throughout gestation (|beta| ranging from 0.168 to 0.415, all p < 0.05). Conclusion A higher intake of whole grain cereals, fruits, vegetables, fish, olive oil and nuts, together with a lower intake of red meat and sweets, resulted in a higher MD adherence, which was associated with a better mental health during pregnancy.

BACKGROUND: Obesity in childhood is a public health concern worldwide and mobile phone-based interventions (mHealth) has shown to facilitate obesity prevention. However, more research is needed on the implementation of digital tools in routine primary care. This study explored behavior change determinants for implementing a health promotion mHealth intervention (MINISTOP 2.0 app) targeting parents of 4-year-olds.

METHODS: Secondary data from telephone interviews (n = 15) with child health care nurses working within primary child healthcare in Sweden was analyzed using directed content analysis and the COM-B model.

RESULTS: Barriers for implementation included: limited knowledge about using technology and reservations about how and to what extent parents would use mHealth. Potential facilitators included nurses' openness to learn and try new tools, confidence in their role and engagement in reaching parents as well as beliefs that the app could improve practice by prompting dialogue and being a shared platform. Nurses expressed a strong professional identity and shared understanding of their practice, mechanisms that could potentially inhibit or facilitate implementation.

CONCLUSIONS: Findings suggest cautious optimism regarding implementing mobile phone-based tools in child primary healthcare in terms of capability, opportunity and motivation among stakeholders. Implementation strategies such as educational outreach visits and making the intervention testable among stakeholders could further facilitate implementation in this clinical context. However, more research is needed on behavior change determinants in different stages of real-world implementation.