Objective: Both adolescents with obesity and those with type 1 diabetes (T1D) exhibit alterations in lipid profiles, but direct comparisons are limited. Comparing lipidomic profiles between obese individuals and those with T1D is crucial for identifying specific metabolic markers, informing tailored interventions, and advancing precision medicine strategies for these distinct populations. The aim of the study was to compare lipidomic profiles between adolescents with obesity and those with T1D, and to analyze associations between metabolites and clinical parameters.
Methods: We included 156 adolescents aged 11–18 years (59.6% girls) from the HEPAFIT (n=114, obesity) and Diactive-1 Cohort (n=42, T1D) studies. Clinical measures included anthropometrics, body composition, lipids, liver enzymes, glucose, and HbA1c. Lipidomic analysis of 277 serum/ plasma metabolites used UHPLC-MS.
Results: Distinct lipid profiles were seen, with higher diglycerides, triglycerides, and certain phosphatidylinositols in the obesity group, while phosphatidylcholines, phosphatidylethanolamines, cholesterol esters, sphingomyelins, and ceramides were elevated in T1D. Triglycerides acyl chain lengths and saturation levels also varied. Multivariate analysis identified seven metabolites –PC(O-18:1/18:1), PC(O-18:1/22:4), PE(O-16:0/18:1), PE(18:2e/22:6), PC(40:1), PC(O22:1/20:4), and PE(P-18:0/18:1)– significantly associated with clinical parameters.
Conclusions: Distinct lipid profiles were observed among adolescents with obesity and T1D in the study, emphasizing the importance of understanding specific metabolite associations with clinical parameters for more precise health management., The HEPAFIT Study was carried out with the financial support of Universidad del Rosario. The content of this paper reflects the author's views alone, and the Colombian Community or the Universidad del Rosario is not liable for any use that may be made of the information contained herein. The Diactive-1 study was funded by grant PI21/01238 from the Instituto de Salud Carlos III (Spain).

Datos de investigación alojados en: https://doi.org/10.2337/figshare.29599814, Objetive: to evaluate the effects of resistance training supported by the mobile health application Diactive-1 on the daily insulin dose and glycemic parameters in children and adolescents with type 1 diabetes.
Rerearch design and methods: in this 24-week randomized clinical trial, Diactive-1 generated progressive overload resistance training sessions tailored to real-time glycemia and provided educational support. Insulin and glycemic parameters were collected from LibreView or CareLink, whereas glycosylated hemoglobin (HbA1c) was extracted from medical records. Muscular strength was assessed using a handgrip dynamometer and e-GYM machines, targeting pushing, pulling, and lower-limb movements. The effect was analyzed using linear mixed models.
Results: sixty-two participants (age: 8–18 years, girls: 48%) with type 1 diabetes (HbA1c: 7.6% [60.4 mmol/mol]) were allocated to the usual care (n = 32) or the Diactive-1 group (n = 30). Daily insulin dose reductions were observed within the Diactive-1 group (mean difference [MD] −0.10 units/kg, 95% CI −0.18 to −0.01) and when compared with usual care (MD −0.17 units/kg, 95% CI −0.26 to −0.07). No adverse effects were observed on the glycemic risk index or the incidence of hypoglycemic events. Finally, handgrip strength (MD 2.90 kg, 95% CI 1.57–4.22), one-repetition maximum strength (MD 1.34, 95% CI 0.21–2.46), and muscular power (MD 0.97, 95% CI 0.01–1.93) increased. Four participants (6.5%) withdrew from the study.
Conclusions: Diactive-1 appears to be a safe and feasible adjunct to standard care in children and adolescents with type 1 diabetes. Its resistance training component effectively reduced insulin requirements and improved muscular strength, without increasing the risk of adverse glycemic events., The study received financial support from Instituto de Salud Carlos III (Spain), funded by the European Union under grant number PI21/01238 and PI24/00829. In addition, Instituto de Salud Carlos III supported J.M.-P. with a competitive contract (FI22/00329).

The aim of the study is to evaluate whether exercise interventions are associated with improved
glycaemic control in children and adolescents with type 1 diabetes mellitus (T1DM), and to
examine its relationship with the characteristics of the intervention (i.e. type, intensity, length,
and duration of the sessions). Eligible criteria were randomised controlled trials of youth aged 6–
18 years with T1DM, participating in an exercise-based intervention where glycaemic control is
measured (i.e. glycated haemoglobin [HbA1c]). Pooled effect sizes (Hedges’g) were calculated
using random-effects inverse-variance analyses. Fourteen studies enrolling 509 patients were
analysed. Effect size was expressed as Hedges’ g to correct for possible small sample bias. Overall,
HbA1c levels in the exercise group (g = –0.38 95% confidence interval [CI], –0.66 to –0.11; mean
difference [MD] = –0.62%) were reduced compared with the control group. Concurrent training (g
= –0.63 95%CI, –1.05 to –0.21), high-intensity exercise (g = –0.43 95%CI, –0.83 to –0.03),
interventions ≥24 weeks (g = –0.92 95%CI, –1.44 to –0.40), and sessions ≥60 minutes (g = –0.71
95%CI, –1.05 to –0.08) showed larger changes (MD = –0.66% to 1.30%). In conclusion, our study
suggests that programmes longer than 24 weeks with at least 60 min/session of high-intensity
concurrent exercise may serve as a supportive therapy to metabolic control in youth with T1DM., This study was funded by grant PI21/01238 from the Instituto de Salud Carlos III (Spain). Dr. García-Hermoso is a Miguel Servet Fellow (Instituto de Salud Carlos III - CP18/0150). The project that gave rise to these results received the support of
a fellowship from la Caixa Foundation granted to Nidia Huerta Uribe (ID 11780038).

Aims: To conduct a meta-analysis of differences in physical activity, sedentary behaviour, and physical fitness
between children and adolescents with type 1 diabetes and their healthy peers.
Methods: The databases EMBASE, PubMed and SportsDiscus were searched for studies. Pooled effects were
calculated using random effects inverse-variance models with the Hartung–Knapp–Sidik–Jonkman adjustment.
Results: Thirty-five studies were included, comprising a total of 4,751 youths (53% girls, 2,452 with type 1
diabetes). Youth with type 1 diabetes were less physically active (Cohen’s d = − 0.23, 95%CI − 0.42 to − 0.04),
more sedentary (Cohen’s d = 0.33, 95%CI 0.06 to 0.61), and had lower cardiorespiratory fitness (Cohen’s d =
− 0.52, 95%CI − 0.73 to − 0.31) than their healthy peers. This corresponds to –12.72 min/day of moderate-tovigorous physical activity, 63.3 min/day of sedentary time (accelerometry) and –4.07 ml/kg/min of
maximum/peak oxygen consumption. In addition, young people with type 1 diabetes were less likely to meet the
international physical activity recommendations than their healthy peers (odds ratio = 0.44, 95%CI 0.31 to
0.62).
Conclusions: Keeping in mind the heterogeneity between studies in the design, population and assessment, our
findings show that children and adolescents with type 1 diabetes seem to be less active, more sedentary, and have
lower cardiorespiratory fitness levels than their healthy peers.

Subjective well-being (SWB), including cognitive and affective components, may be influenced by the management of type 1diabetes mellitus (T1DM). Physical fitness and adherence to physical activity (PA) are associated with better glycaemic stabilityand diabetes management. However, the relationship with SWB is not yet understood. The aim of the study was to determinethe relationship between physical fitness, PA, and SWB over two years in youths with T1DM. This longitudinal study involved83 participants (aged 6–18 years; 44.6% girls) from the Diactive-1 Cohort. Physical fitness was assessed by spirometry (peak ox-ygen consumption) and dynamometry (handgrip strength). PA domains were measured using triaxial accelerometers, whereasthe number of days participating in muscle-strengthening activities was assessed using a question. The Cuestionario Único deBienestar Escolar was used to determine SWB. Glycaemic stability was determined when glycosylated hemoglobin < 7%, coef-ficient of variability ≤ 36%, and time-in-range target > 70% were met. The linear mixed models used considered three assess-ments and subject variability, showing significant associations between overall physical fitness (unstandardized beta coefficient[B] = 1.778, 95% confidence interval [CI] 0.413–3.158; p = 0.012) and total PA (B = 0.034, 95% CI 0.005–0.063; p = 0.020) withSWB. Although time did not moderate the association with physical fitness (p = 0.116), this was true for PA only in the secondyear (p = 0.020). In contrast, glycaemic stability did not moderate the associations (p > 0.05). In conclusion, physical fitness andPA are associated with greater SWB in young people with T1DM, which may play a role in the psychological aspects of diseasemanagement., This study was supported by a grant PI21/01238 and PI24/00829 from the Instituto de Salud Carlos III-ERDF (Spain). The project that gave riseto these results received the support of a fellowship form 'Instituto de Salud Carlos III' granted to Jacinto Muñoz-Pardeza (FI22/00329).

Aims: To develop and validate the psychometric properties, reliability, and criterion validity of the Physical Activity Barriers Scale for pediatric type 1 diabetes (PABS-1) in Spanish-speaking children and adolescents with type 1 diabetes.
Method: A cross-sectional study was conducted with a sample of 93 Spanish-speaking children and adolescents with type 1 diabetes. The PABS-1 questionnaire was developed by experts and refined with patient feedback. Its validity was assessed by comparing results with accelerometer data, linking scores to objective physical activity measures.
Results: The PABS-1 showed good internal consistency, with a Cronbach’s alpha (α) coefficient of 0.89, indicating strong reliability. Confirmatory factor analysis supported a four-factor structure, with physical, diabetes-related, psychological, and environmental barriers showing good fit indices (comparative fit index [CFA] = 0.94, root mean square error of [RMSEA] = 0.06, standardized root mean square residual [SRMR] = 0.05). Although the associations were small, the total PABS-1 score was significantly negatively correlated with cardiorespiratory fitness (Spearman’s rho [ρ]= -0.15, p = 0.035) and moderate-to-vigorous physical activity (ρ = − 0.12, p = 0.039). Among the four factors, motivational barriers exhibited the strongest associations with physical activity and fitness, showing significant negative correlations.
Conclusions: The PABS-1 is a valid and reliable tool for assessing perceived barriers to physical activity in Spanish-speaking children and adolescents with type 1 diabetes., This study was funded by grant PI21/01238 from the Instituto de Salud Carlos III - ERD (Spain). The project that gave rise to these results received the support of a fellowship from Instituto de Salud Carlos III granted to Jacinto Muñoz-Pardeza (FI22/00329). Open access funding provided by Universidad Pública de Navarra.

Background: in type 1 diabetes, telomere length (TL) may predict complications and could be influenced by glycaemic control and physical activity, but its relationship with physical fitness in youths remains unexplored. The aim of the study was to assess the association between physical fitness and TL in youth with type 1 diabetes, both at baseline and one year later.
Methods: eighty-three children and adolescents (aged 6-18 years; 44.6% girls) with type 1 diabetes from the Diactive-1 Cohort Study were involved in this study. Physical fitness was assessed using spirometry on a cycloergometer (i.e., peak oxygen consumption), dynamometry, and maximal isometric strength (one-repetition maximum [1RM]), and muscle power. Leucocyte TL was assessed using multiplex monochrome real-time quantitative polymerase chain reaction.
Results: positive cross-sectional associations were identified between 1RM (unstandardized beta coefficient [B] = 0.042, 95% bias corrected and accelerated [BCa] confidence interval [CI] 0.012-0.069), muscle power (B = 0.056, 95% BCa CI 0.02-0.250), and overall physical fitness (B = 0.043, 95% BCa CI 0.015¿0.071) with TL independent of maturation, glycated haemoglobin, and diabetes duration. However, no associations were observed one year later.
Conclusion: higher levels of fitness, particularly muscle strength, may play a role in telomere dynamics in youth with type 1 diabetes, suggesting that strength training exercise could be beneficial.
Impact: this is the first study to examine cross-sectional and longitudinal perspectives on the correlation among muscle strength, peak oxygen consumption [VO2peak] and telomere length in youths with type 1 diabetes.
Higher physical fitness levels, as assessed by measures such as one-repetition maximum, muscle power, and overall physical fitness, are positively associated with telomere length in youths with type 1 diabetes.
Understanding this link could improve management strategies, prioritizing muscle strength training for better long-term health in type 1 diabetes., This study was funded by grant PI21/01238 from the Instituto de Salud Carlos III (Spain) and by CIBER of Obesity Physiology and Nutrition (CB12/03/30002). The project that gave rise to these results received the support of a fellowship form 'Instituto de Salud Carlos III' granted to Jacinto Muñoz-Pardeza (FI22/00329). Dr. Ana Ojeda-Rodriguez is the recipient of a Sara Borrell grant (CD21/00099) from the Instituto de Salud Carlos III. The origin of obtaining results was supported by a scholarship from the 'la Caixa' Foundation awarded to Nidia Huerta Uribe (DNI 11780038).

Studies on fear of hypoglycemia as a barrier to physical activity among youth
with type 1 diabetes (T1D) have been limited and controversial, most of which
used self-reported assessment. The aim of the study was to evaluate the relationship between fear of hypoglycemia and physical activity and glycemic metrics
in children and adolescents with T1D. Seventy-four participants (6–18 years
of age; 44.6% females) with T1D were included in the study. Physical activity
was assessed through accelerometry on nine consecutive days, and blood glucose metrics were simultaneously tracked using continuous glucose monitoring
(time-in-range and hypoglycemic events). A closed question was used to evaluate the avoidance of physical activity due to fear of hypoglycemia. Fifteen participants (20%) reported avoiding physical activity due to fear of hypoglycemia.
The group reporting no fear of hypoglycemia showed lower total physical activity
(−35.33min/day, 95% confidence interval [CI] (−77.57 to −1.47)) and light physical activity (−29.81min/day, 95% CI −64.01 to −2.75) and higher sedentary time
(77.95min/day, 95% CI 26.46–136.87) per day compared with those with fear of
hypoglycemia. No difference was found between those patients with fear of hypoglycemia in terms of meeting the recommendations of glycated hemoglobin,
glucose coefficient of variation, and time-in-range when compared to those with
no fear of hypoglycemia. In conclusion, children and adolescents with fear of
hypoglycemia were more active, less sedentary, and had similar glycemic metrics
to those without fear. Our results therefore suggest that fear of hypoglycemia may
be less of a barrier to an active lifestyle than previously believed., This study was funded by grant PI21/01238 from the Instituto de Salud Carlos III (Spain). Dr. García-Hermoso is a Miguel Servet Fellow (Instituto de Salud Carlos III – CP18/0150). The project that gave rise to these results received the support of a fellowship from “la Caixa” Foundation granted to Nidia Huerta Uribe (ID 11780038). Open access funding provided by Universidad Pública de Navarra.

The available evidence on the impact of specific non-pharmacological interventions on glycaemic control is currently limited. Consequently, there is a need to determine which interventions could provide the most significant benefits for the metabolic health of young individuals with type 1 diabetes mellitus. The aim of this study was to identify optimal nonpharmacological interventions on glycaemic control, measured by glycated haemoglobin (HbA1c), in children and adolescents with type 1 diabetes. Systematic searches were conducted in PubMed, Web of Science, Scopus, and SPORTDiscus from inception to July 1, 2023. Randomised clinical trials (RCT) investigating nonpharmacological interventions (e.g., physical activity, nutrition, and behavioural therapies) were included. Primary outcome was change in HbA1c levels. Secondary outcome was change in daily insulin dose requirement. Seventy-four RCT with 6,815 participants (49.43% girls) involving 20 interventions were analysed using a network meta-analysis. Most interventions showed greater efficacy than standard care. However, multicomponent exercise, which includes aerobic and strength training (n = 214, standardised mean difference [SMD] =– 0.63, 95% credible interval [95% CrI] – 1.09 to – 0.16) and nutritional supplements (n = 146, SMD =– 0.49, – 0 .92 to – 0.07) demonstrated the greatest HbA1c reductions. These interventions also led to the larger decreases in daily insulin needs (n = 119, SMD =– 0.79, 95% CrI – 1.19 to – 0.34) and (n = 57, SMD =– 0.62, 95% CrI – 1.18 to – 0.12, respectively). The current study underscores non-pharmacological options such as multicomponent exercise and nutritional supplements, showcasing their potential to significantly improve HbA1c in youth with type 1 diabetes. Although additional research to confirm their efficacy is required, these approaches could be considered as potential adjuvant therapeutic options in the management of type 1 diabetes among children and adolescents., This study was funded by grant PI21/01238 from the Instituto de Salud Carlos III (Spain). The project that gave rise to these results received the support of a fellowship form “Instituto de Salud Carlos III” granted to Jacinto Muñoz-Pardeza (FI22/00329). The project that gave rise to these results received the support of a fellowship from “la Caixa” Foundation granted to Nidia Huerta Uribe (ID 11780038).

Aims: To establish sex-specific peak oxygen consumption (VO2peak) thresholds that accurately discriminate cardiometabolic risk (CMR) in children and adolescents with type 1 diabetes and to validate these cut-off points using an independent cohort.
Methods: This longitudinal study included 83 participants (aged 8–18 years) with type 1 diabetes from the Diactive-1 cohort. VO2peak was assessed via maximal exercise testing with direct gas analysis, and CMR was calculated using a composite z-score of waist circumference, lipid profile, HbA1c, and blood pressure. VO2peak thresholds for CMR were identified by sex using logistic regression and receiver operating characteristic analysis, and externally validated in a Brazilian cohort (n = 36). A total of 62 individuals completed the 2-year follow-up assessment.
Results: Optimal VO2peak thresholds were 40.8 ml/kg/min for boys and 33.7 ml/kg/min for girls, with areas under the curve of 0.71 and 0.78, respectively. Participants below these thresholds had significantly higher lipids and overall CMR. These associations persisted at the two-year follow-up and were confirmed in the Brazilian cohort, which also showed elevated HbA1c among high-risk individuals.
Conclusions: Our study supports the clinical utility of these thresholds as a non-invasive marker of metabolic health and reinforce the importance of cardiorespiratory fitness promotion in this population., This study was funded by grant PI21/01238 from the Instituto de Salud Carlos III (Spain) and co-funded by de European Union. The project that gave rise to these results received the support of a fellowship form Instituto de Salud Carlos III granted to Jacinto Muñoz-Pardeza (FI22/00329). Open Access funding provided by Universidad Pública de Navarra.

Introduction: The use of new technologies presents an opportunity to promote physical activity, especially among young people with type 1 diabetes (T1DM), who tend to be less active compared to their healthy counterparts. The aim of this study is to investigate the impact of a personalized resistance exercise program, facilitated by the Diactive-1 App, on insulin requirements among children and adolescents diagnosed with T1DM.
Methods and analysis: A minimum of 52 children and adolescents aged 8-18 years, who were diagnosed with T1DM at least 6 months ago, will be randomly assigned to either a group engaging in an individualized resistance exercise program at least 3 times per week over a 24-week period or a waiting-list control group. The primary outcome will be the daily insulin dose requirement. The secondary outcomes will include glycemic control, cardiometabolic profile, body composition, vascular function, physical fitness, 24-hour movement behaviors, diet, and psychological parameters. The usability of the app will also be assessed.
Ethics and dissemination: Ethical approval to conduct this study has been granted by the University Hospital of Navarra Research Board (PI_2020/140). Parents or legal guardians of minors participating in the study will provide written consent, while children and adolescents will sign an assent form to indicate their voluntary agreement. The trial's main findings will be shared through conference presentations, peer-reviewed publications, and communication directly with participating families. This study aims to offer valuable insights into the holistic management of children and adolescents with T1DM by utilizing personalized exercise interventions through an mHealth system., This study was funded by grant PI21/01238 from the Instituto de Salud Carlos III - ERDF (Spain).

Background: Managing physical activity alongside glucose levels is challenging for children and adolescents with type 1 diabetes mellitus (T1DM). This study aimed to evaluate the usability of the Diactive-1 app, which was designed to support muscle-strengthening training in children and adolescents with T1DM in accordance with guidelines from the International Society for Pediatric and Adolescent Diabetes (ISPAD) and the American Diabetes Association (ADA).
Methods: Twenty-seven patients aged 8–18 years with T1DM were randomly selected. Recruitment was conducted through the Pediatric Endocrinology Unit of the University Hospital of Navarra (Spain). All participants were enrolled in a randomized controlled trial and used the Diactive-1 app during the intervention. The study lasted 24 weeks, during which the app provided personalized muscle-strengthening exercise sessions, glucose monitoring, and motivational features such as gamification. Usability of the app was assessed using the User Version of the Mobile Application Rating Scale (uMARS).
Results: The Diactive-1 app demonstrated high usability, with an overall quality mean score of 4.33 [standard deviation (SD) =0.36] out of 5.00. uMARS objective domains ratings were: functionality [4.52 (SD =0.40)], aesthetics [4.43 (SD =0.45)], engagement [4.07 (SD =0.51)], information quality [4.29 (SD =0.75)], and subjective quality score was 3.94 (SD =0.61). Usability scores showed no meaningful variation across patient demographics, including sex, age, glycated hemoglobin, engagement in muscle-strengthening activities, and fear of hypoglycemia, suggesting consistent app performance among different user groups.
Conclusions: The Diactive-1 app is a promising tool for integrating muscle-strengthening training and educating patients about safe physical exercise into the management of T1DM in children and adolescents. Its high usability and positive user feedback underscore its potential as an effective supportive strategy for managing the disease in this population. Further refinement of personalization features may enhance its effectiveness., This study was funded by a grant PI21/01238 from the Instituto de Salud Carlos III - ERDF (Spain). The project that gave rise to these results received the support of a fellowship form 'Instituto de Salud Carlos III' granted to Jacinto Muñoz-Pardeza (No. FI22/00329).

Objective: this study aimed to explore the association between handgrip strength, cardiometabolic risk (CMR) and body composition in youth with type 1 diabetes.
Methods: for this prospective cohort study, muscular fitness was assessed via handgrip test and relativised by weight, and body composition, evaluated through dual-energy X-ray absorptiometry in type 1 diabetes patients aged 6-18 years. CMR score included z-scores for total body fat, blood pressure, glycated haemoglobin (HbA1c), low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglyceride-glucose index.
Results: eighty-three patients were analysed at baseline and 1-year follow-up (44.6% females, mean age 12.77 years). Individuals with high handgrip strength tended to have lower CMR and body fat compared with those with low handgrip strength. Over a year, individuals with high handgrip strength showed reduced HbA1c, CMR and subcutaneous fat. Consistently meeting high handgrip strength criteria resulted in reductions in HbA1c levels, CMR score and subcutaneous adipose tissue compared with those who never complied or lost compliance during follow-up. Additionally, subjects classified with high handgrip strength both at baseline and follow-up had a lower likelihood of being classified with high CMR (OR=0.241, 95% CI 0.121 to 0.947, p=0.044).
Conclusions: high handgrip strength was associated with significant cardiometabolic and body composition benefits in youth with type 1 diabetes. This tool could be considered of potential clinical value for incorporating assessments like handgrip tests to monitor and address cardiometabolic health., This study was funded by grant PI21/01238 from the Instituto de Salud Carlos III-ERFD (Spain). The project that gave rise to these results received the support of a fellowship from 'Instituto de Salud Carlos III' granted to JM-P (FI22/00329). The project that gave rise to these results received the support of a fellowship from 'la Caixa' Foundation granted to Nidia Huerta Uribe (ID 11780038).

Aims/hypothesis. The aim of this study was to examine the association of physical activity, sedentarism and sleep with HbA1c and interstitial glucose in children and adolescents with type 1 diabetes through a 24 h compositional analysis.
Methods. The study involved 83 young people diagnosed with type 1 diabetes (aged 6–18 years; 45% girls, mean HbA1c 57.54 ± 9.22 mmol/mol (7.4 ± 0.8%); median interstitial glucose 9.37 mmol/l [IQR 8.68–10.31]) from the Diactive-1 cohort study, followed up for 2 years. A triaxial accelerometer was used to objectively measure 24 h movement behaviours for 9 days. HbA1c levels were obtained from medical records, and interstitial glucose data were collected through continuous glucose monitoring. Linear mixed models were used to quantify associations between movement behaviours, interstitial glucose and HbA1c, maintaining the relative nature of the data based on the 24 h day.
Results. A higher daily amount of sedentary behaviour, at the expense of sleep time, light or moderate-to-vigorous physical activity, was positively associated with HbA1c (unstandardised beta coefficient [B]=14.077 [95% CI 4.244, 23.956]; standardised beta coefficient [β]=0.368) and interstitial glucose (B=1.988; 95% CI 0.153, 3.880; β=0.261), while more sleep time, at the expense of sedentary behaviour, light or moderate-to-vigorous physical activity, was associated with a significant reduction in HbA1c (B=−12.712; 95% CI −25.204, −0.520; β=−0.197). Furthermore, reductions in both interstitial glucose (B=−1.580; 95% CI −2.800, −0.388; β=−0.283) and HbA1c (B=−9.361; 95% CI −15.856, −2.881; β=−0.330) were observed with increased daily time spent in moderate-to-vigorous physical activity at the expense of sedentary behaviour. Overall, the standardised beta coefficients indicated small to moderate effect sizes.
Conclusions/interpretation. Our findings indicate that lower sedentary behaviour and more optimal sleep and physical activity patterns are associated with greater metabolic stability in children and adolescents with type 1 diabetes. These findings support the need for further research on balancing these behaviours for better diabetes management, and encourage adoption of a 24 h movement approach in clinical care., This study was funded by grant PI21/01238 and PI24/00829 from the Instituto de Salud Carlos III, and co-funded by the European Union. The project that gave rise to these results received the support of a fellowship from 'Instituto de Salud Carlos III' granted to JM-P (FI22/00329). Open access funding is provided by Universidad Pública de Navarra.

Aims This study sought to elucidate the interactions among physical activity (PA) patterns, mean glucose concentrations, and the incidence of nocturnal hypoglycemia events in children and adolescents with type 1 diabetes, examining the moderating influence of daily dosage on these associations.Methods Eighty-two participants aged 6 to 18 years (43.9% girls) from the Diactive-1 Cohort Study, diagnosed with type 1 diabetes, were included. Data collection involved continuous glucose monitoring, accelerometry to assess real-world PA, as well as documentation of daily insulin doses and carbohydrate counting over the same 7 days.Results A total of 19 participants experienced at least 1 nocturnal hypoglycemia event over a span of 574 measurement days (106 days with and 451 days without nocturnal hypoglycemia). Higher levels of vigorous PA (VPA) were associated with lower same-day mean glucose levels (P = .014). Additionally, higher levels of moderate PA (P = .023), VPA (P = .011), and moderate-to-vigorous PA (P = .010) were associated with a greater number of nocturnal hypoglycemia events. Specifically, a significant association was identified between VPA and nocturnal hypoglycemia events when the daily insulin dose was at or above 1.04 units per kilogram of body weight per day (P = .016).Conclusion Daily VPA is associated with glucose reductions, potentially leading to more hypoglycemic episodes, particularly when there is an excess of daily insulin. This highlights the need for careful insulin management in children and adolescents with type 1 diabetes engaging in VPA., This study was funded by grant PI21/01238 from the Instituto de Salud Carlos III-ERDF (Spain). The project that gave rise to these results received the support of a fellowship form Instituto de Salud Carlos III granted to J.M.P. (FI22/00329).

El tutor de la tesis es Mikel Izquierdo Redín, El objetivo principal de esta tesis doctoral fue determinar si la actividad física, la conducta sedentaria y la condición física están asociados con el control glucémico y los factores de riesgo cardiovascular en niños y adolescentes con diabetes mellitus tipo 1, así como determinar si estos parámetros difieren de aquellos en jóvenes aparentemente sanos. Para cumplir este objetivo y dar respuesta a las diversas preguntas que surgieron durante la ejecución del proyecto, se plantearon una serie de revisiones de la literatura existente y diversos análisis de los datos recogidos de la cohorte Diactive-1. Así pues, el Estudio de Cohorte Diactive-1 dio lugar a 4 artículos científicos:
Primer estudio: Los jóvenes con diabetes mellitus tipo 1 son más inactivos y sedentarios que sus pares sanos. Objetivo: llevar a cabo un meta-análisis de las diferencias en actividad física, conducta sedentaria y capacidad cardiorrespiratoria entre niños y adolescentes con diabetes mellitus tipo 1 y jóvenes sanos. Conclusiones: teniendo en cuenta la heterogeneidad entre los estudios en cuanto al diseño, la población y la evaluación, nuestros hallazgos indican que los niños y adolescentes con diabetes tipo 1 parecen ser menos activos, más sedentarios y tener niveles más bajos de condición cardiorrespiratoria en comparación con sus pares saludables.
Segundo estudio: ¿Es el miedo a la hipoglucemia una barrera importante para un estilo de vida activo en niños y adolescentes con diabetes tipo 1? Estudio Diactive-1. Objetivo: evaluar la relación entre el miedo a la hipoglucemia y la actividad física, así como las métricas glucémicas, en niños y adolescentes con diabetes tipo 1. Conclusiones: los niños y adolescentes con miedo a la hipoglucemia fueron más activos, menos sedentarios y presentaron métricas glucémicas similares a los que no tenían miedo. Por lo tanto, nuestros resultados sugieren que el miedo a la hipoglucemia puede ser una barrera para un estilo de vida activo menos relevante de lo que se creía anteriormente.
Tercer estudio: Asociación entre actividad física, conducta sedentaria y condición física y la hemoglobina glucosilada en jóvenes con diabetes tipo 1: Una revisión sistemática con meta-análisis. Objetivo: realizar un meta-análisis de la asociación entre la hemoglobina glucosilada y la actividad física, el comportamiento sedentario y la condición física en niños y adolescentes con diabetes tipo 1. Conclusiones: niveles bajos de actividad física y capacidad cardiorrespiratoria, junto con un comportamiento sedentario, parecen explicar parte de la variabilidad en la hemoglobina glucosilada y del riesgo de un control glucémico no óptimo en jóvenes con diabetes tipo 1.

Cuarto estudio: Fuerza de prensión manual, riesgo cardiometabólico y composición corporal en jóvenes con diabetes tipo 1. Objetivo: explorar la asociación entre la fuerza de prensión manual, el riesgo cardiometabólico y la composición corporal en jóvenes con diabetes tipo 1. Conclusiones: una fuerza de prensión manual saludable brinda beneficios significativos para la salud cardiometabólica y la composición corporal en jóvenes con diabetes tipo 1. Este estudio destaca el valor clínico potencial de esta herramienta para incorporar evaluaciones como la prueba de prensión manual para monitorizar e intervenir en la salud cardiometabólica., The main purpose of this doctoral thesis was to determine whether the physical activity (PA), sedentary behavior and physical fitness were associated with the glycemic control and cardiovascular risk factors in children and adolescents with T1D, and if these parameters differed from those in apparently healthy peers. In order to fulfill this objective and answer a variety of questions that arose during the execution of the project, a series of reviews of existing data and analyses of our own data were carried out and reported. Thus, the Diactive-1 Cohort Study gave rise to four studies:

First study: Youth with type 1 diabetes mellitus are more inactive and sedentary than apparently healthy peers: A systematic review and meta-analysis. Aim: To conduct a meta-analysis of differences in PA, sedentary behavior, and physical fitness between children and adolescents with T1D and their healthy peers. Conclusions: Keeping in mind the heterogeneity between studies in the design, population and assessment, our findings show that children and adolescents with T1D seem to be less active, more sedentary, and have lower CRF levels than their healthy peers.

Second study: Is fear of hypoglycemia a major barrier to an active lifestyle in children and adolescents with type 1 diabetes? The Diactive-1 Study. Aim: To evaluate the relationship between fear of hypoglycemia (FoH) and PA and glycemic metrics in children and adolescents with T1D. Conclusions: Children and adolescents with FoH were more active, less sedentary, and had similar glycemic metrics to those without fear. Our results therefore suggest that FoH may be less of a barrier to an active lifestyle than previously believed.

Third study: Association Between Physical Activity, Sedentary Behavior and Physical Fitness and Glycated Hemoglobin in Youth with Type 1 Diabetes: A Systematic Review and Meta-analysis. Aim: To meta-analyze the association between A1c and PA, sedentary behavior, and physical fitness in children and adolescents with T1D. Conclusions: Low levels of PA and CRF and extensive sedentary behavior may explain part of the variance in A1c and part of the risk for poor glycemic control in youth with T1D.

Fourth study: Handgrip strength, cardiometabolic risk, and body composition in youth with type 1 diabetes. Aim: To explore the association between handgrip strength, cardiometabolic risk, and body composition in youth with T1D. Conclusions: Healthy handgrip strength provides significant cardiometabolic and body composition benefits for youth with T1D. This tool could be considered of potential clinical value in incorporating assessments like handgrip tests to monitor and intervene regarding cardiometabolic health., Financiado por el Instituto de Salud Carlos III (PI21/01238) y beca de la Fundación La Caixa (ID 11780038), Programa de Doctorado en Ciencias de la Salud (RD 99/2011), Osasun Zientzietako Doktoretza Programa (ED 99/2011)

Context Type 1 diabetes in youth increases the risk of compromised bone health due to glycemic dysregulation. Muscular fitness may play a role in improving bone health during growth. Objective This study aimed to investigate the association between muscular fitness and bone health in youth with type 1 diabetes. Methods A total of 83 young individuals with type 1 diabetes (aged 6-18 years; 44.6% girls) from the Diactive-1 cohort study were followed for 2 years. Dual-energy x-ray absorptiometry whole-body scans were used to assess bone mineral content (BMC) and areal bone mineral density (aBMD) of the total body less head (TBLH), arms, legs, pelvis, and spine. Muscular fitness (handgrip strength, 1 repetition maximum, and muscle power) was assessed with a dynamometer and eGYM devices. Handgrip strength and TBLH bone parameters were age- and sex-standardized using the FitBack Project and BMD Childhood Study, respectively. Results Linear mixed models showed longitudinal associations of handgrip strength with TBLH-BMC (unstandardized beta coefficient [B] = 17.18, 95% confidence interval [CI] 12.47-21.90) and TBLH-aBMD (B = 0.004, 95% CI 0.002-0.006); RM with TBLH-BMC (B = 20.09, 95% CI 10.88-29.31) and TBLH-aBMD (B = 0.007, 95% CI 0.004-0.011); and power with TBLH-BMC (B = 26.80, 95% CI: 17.31-36.28) and TBLH-aBMD (B = 0.009, 95% CI 0.005-0.012). Comparable results were observed across the other regions (P < .05). Additionally, analyses with standardized data confirmed the relationships of handgrip z-scores with TBLH-BMC z-scores (B = 0.19, 95% CI 0.08-0.30) and TBLH-aBMD z-scores (B = 0.350, 95% CI: 0.210-0.490). Conclusion In pediatric patients with type 1 diabetes, higher muscular fitness could serve as a complementary therapeutic strategy to preserve or enhance bone health., This study was funded by grant PI21/01238 and PI24/00829 from the Instituto de Salud Carlos III-ERDF (Spain). The project that gave rise to these results received the support of a fellowship form Instituto de Salud Carlos III granted to Jacinto Munoz-Pardeza (FI22/00329).