Muscular fitness mediates the association between 25-hydroxyvitamin D and areal bone mineral density in children with overweight/obesity

The association between vitamin D [25(OH)D] and bone health has been widely studied in children. Given that 25(OH)D and bone health are associated with muscular fitness, this could be the cornerstone to understand this relationship. Hence, the purpose of this work was to examine if the relation between 25(OH)D and areal bone mineral density (aBMD) was mediated by muscular fitness in children with overweight/obesity. Eighty-one children (8-11 years, 53 boys) with overweight/obesity were included. Body composition was measured with dual energy X-ray Absorptiometry (DXA), 25(OH)D was measured in plasma samples and muscular fitness was assessed by handgrip and standing long jump tests (averaged z-scores were used to represent overall muscular fitness). Simple mediation analyses controlling for sex, years from peak height velocity, lean mass and season were carried out. Our results showed that muscular fitness z-score, handgrip strength and standing long jump acted as mediators in the relationship between 25(OH)D and aBMD outcomes (percentages of mediation ranged from 49.6% to 68.3%). In conclusion, muscular fitness mediates the association of 25(OH)D with aBMD in children with overweight/obesity. Therefore, 25(OH)D benefits to bone health could be dependent on muscular fitness in young ages

Effects of an exercise program on cardiometabolic and mental health in children with overweight or obesity: a secondary analysis of a randomized clinical trial

Importance: Childhood obesity is a risk factor associated with type 2 diabetes, cardiovascular disease, and mental disorders later in life. Investigation of the parallel effects of a defined exercise program on cardiometabolic and mental health in children with overweight or obesity may provide new insights on the potential benefits of exercise on overall health. Objective: To investigate the effects of a 20-week exercise program on cardiometabolic and mental health in children with overweight or obesity. Design, Setting, and Participants: This secondary analysis of a parallel-group randomized clinical trial was conducted in Granada, Spain, from November 1, 2014, to June 30, 2016. Data analyses were performed between February 1, 2020, and July 14, 2022. Children with overweight or obesity aged 8 to 11 years were eligible, and the study was performed in an out-of-school context. Intervention: The exercise program included 3 to 5 sessions/wk (90 min/session) of aerobic plus resistance training for 20 weeks. The wait-list control group continued with their usual routines. Main Outcomes and Measures: Cardiometabolic outcomes as specified in the trial protocol included body composition (fat mass, fat-free mass, and visceral adipose tissue), physical fitness (cardiorespiratory, speed-agility, and muscular), and traditional risk factors (waist circumference, blood lipid levels, glucose levels, insulin levels, and blood pressure). Cardiometabolic risk score (z score) was calculated based on age and sex reference values for levels of triglycerides, inverted high-density lipoprotein cholesterol, and glucose, the mean of systolic and diastolic blood pressure, and waist circumference. An additional cardiometabolic risk score also included cardiorespiratory fitness. Mental health outcomes included an array of psychological well-being and ill-being indicators. Results: The 92 participants included in the per-protocol analyses (36 girls [39%] and 56 boys [61%]) had a mean (SD) age of 10.0 (1.1) years. The exercise program reduced the cardiometabolic risk score by approximately 0.38 (95% CI, -0.74 to -0.02) SDs; decreased low-density lipoprotein cholesterol level by -7.00 (95% CI, -14.27 to 0.37) mg/dL (to convert to mmol/L, multiply by 0.0259), body mass index (calculated as weight in kilograms divided by height in meters squared) by -0.59 (95% CI, -1.06 to -0.12), fat mass index by -0.67 (95% CI, -1.01 to -0.33), and visceral adipose tissue by -31.44 (95% CI, -58.99 to -3.90) g; and improved cardiorespiratory fitness by 2.75 (95% CI, 0.22-5.28) laps in the exercise group compared with the control group. No effects were observed on mental health outcomes. Conclusions and Relevance: In this secondary analysis of a randomized clinical trial, an aerobic plus resistance exercise program improved cardiometabolic health in children with overweight or obesity but had no effect on mental health. Trial Registration: ClinicalTrials.gov Identifier: NCT02295072.This project was supported with grants DEP2013-47540, DEP2016-79512-R, DEP2017-91544-EXP, and RYC-2011-09011 from the Spanish Ministry of Economy and Competitiveness and the Fondo Europeo de Desarrollo Regional (FEDER) and by grant PID2020-120249RB-I00 from the MCIN/AEI /10.13039/501100011033. Additional funding was obtained from the Andalusian Operational Programme supported with grant B-CTS-355-UGR18 from the European Regional Development Fund (FEDER in Spanish). Dr Cardenas-Sanchez is supported by grant FJC2018-037925-I from the Spanish Ministry of Science and Innovation and by a grant from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska Curie grant agreement No 101028929. Dr Migueles is supported by grant FPU15/02645 from the Spanish Ministry of Education, Culture and Sport, and grant 2012–00036 from the Swedish Research Council for Health, Working Life and Welfare. Dr Torres-Lopez is supported by grant FPU17/04802 from the Spanish Ministry of Science, Innovation and Universities. Dr Rodriquez-Ayllon was funded by grant DEP2017-91544-EXP from the Ramón Areces Foundation. Additional support was obtained from grant ALICIAK-2018 from the Alicia Koplowitz Foundation, University of Granada, Plan Propio de Investigación 2016, Excellence actions: Units of Excellence, Unit of Excellence on Exercise, Nutrition and Health, the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades; and grant DEP2005-00046/ACTI from the EXERNET Research Network on Exercise and Health in Special Populations. This research was supported by grant CB22/03/00058 from the Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación and Unión Europea–European Regional Development Fund