{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,14]],"date-time":"2026-08-14T04:31:00Z","timestamp":1786681860997,"version":"build-2736575974"},"reference-count":32,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,14]],"date-time":"2026-08-14T00:00:00Z","timestamp":1786665600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Endocrinol."],"abstract":"<jats:p>This study identified longitudinal trajectories of lean mass development from childhood to young adulthood and examined their associations with bone and muscle outcomes in early adulthood. Data were obtained from 323 participants (8\u201323 years) in the Iowa Bone Development Study, assessed at 7 time points. Lean mass trajectories were defined using DXA-derived Z-scores for the appendicular lean mass index (aLBMI) and the appendicular lean mass to trunk fat mass ratio (aLBM\/TrFM), categorized as low, average, or high. Only participants with consistent trajectories were included (n=116 for aLBMI; n=67 for aLBM\/TrFM). At 23 years, bone material (DXA aBMD and pQCT vBMD), bone structure (pQCT geometry and strength), and muscle composition (pQCT muscle area and density) were assessed. Linear regression used the average trajectory as a reference and was adjusted for sex and height. A low aLBMI trajectory was associated with lower aBMD at the whole body less head (WBLH), femoral neck, and trochanter (\u22128% to \u221211%) and reduced tibial structural strength (\u221223% to \u221234%), with no differences at the radius. Higher aLBMI trajectories were associated with higher aBMD (up to +17%), greater bone strength in the tibia and radius (+22 to 45%), and larger muscle area (+32%). For aLBM\/TrFM, only WBLH aBMD differed, with the high group showing ~5% higher values, along with lower BMI and higher muscle density. These findings suggest that consistent longitudinal patterns of lean mass development are associated with bone and muscle outcomes in early adulthood, with aLBMI more closely related to bone structure and muscle area, while a favorable muscle-to-fat ratio may reflect better muscle quality and whole-body bone status.<\/jats:p>","DOI":"10.3389\/fendo.2026.1898386","type":"journal-article","created":{"date-parts":[[2026,8,14]],"date-time":"2026-08-14T04:23:22Z","timestamp":1786681402000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Lean mass development trajectories in children and adolescents and their associations with musculoskeletal health in emerging adulthood"],"prefix":"10.3389","volume":"17","author":[{"given":"M.","family":"Marques","sequence":"first","affiliation":[{"name":"CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa","place":["Lisbon, Portugal"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"F.","family":"Baptista","sequence":"additional","affiliation":[{"name":"CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa","place":["Lisbon, Portugal"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"O.","family":"Rysavy","sequence":"additional","affiliation":[{"name":"Division of Biostatistics and Computational Biology, University of Iowa","place":["Iowa City, IA, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C.","family":"Pendleton","sequence":"additional","affiliation":[{"name":"Division of Biostatistics and Computational Biology, University of Iowa","place":["Iowa City, IA, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S. M.","family":"Levy","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, University of Iowa","place":["Iowa City, IA, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K. F.","family":"Janz","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, University of Iowa","place":["Iowa City, IA, United States"]},{"name":"Department of Health and Human Physiology, University of Iowa","place":["Iowa City, IA, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,14]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1046\/j.1467-789x.2001.00031.x","article-title":"Beyond body mass index","volume":"2","author":"Prentice","year":"2001","journal-title":"Obes Rev"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1467-789X.2011.00952.x","article-title":"Waist-to-height ratio is a better screening tool than waist circumference and BMI for adult cardiometabolic risk factors: Systematic review and meta-analysis","volume":"13","author":"Ashwell","year":"2012","journal-title":"Obes Reviews: Off J Int Assoc For Study Obes"},{"key":"B3","doi-asserted-by":"publisher","first-page":"5","DOI":"10.1016\/j.clnu.2019.04.012","article-title":"Low muscle mass and strength in pediatrics patients: Why should we care","volume":"38","author":"Orsso","year":"2019","journal-title":"Clin Nutr"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1016\/j.clnu.2011.12.011","article-title":"Body composition: Why, when and for who","volume":"31","author":"Thibault","year":"2012","journal-title":"Clin Nutr (Edinburgh Scotland)"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1016\/j.cger.2011.03.007","article-title":"Sarcopenia and obesity","volume":"27","author":"Waters","year":"2011","journal-title":"Clinics Geriatric Med"},{"key":"B6","doi-asserted-by":"publisher","first-page":"5","DOI":"10.1007\/s00223-001-0048-8","article-title":"The \u00abmuscle-bone unit\u00bb in children and adolescents","volume":"70","author":"Schoenau","year":"2002","journal-title":"Calcif Tissue Int"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.1007\/s00223-014-9915-y","article-title":"Skeletal muscle: A brief review of structure and function","volume":"96","author":"Frontera","year":"2015","journal-title":"Calcif Tissue Int"},{"key":"B8","doi-asserted-by":"publisher","DOI":"10.1002\/jbmr.323","article-title":"Effects of repetitive loading on the growth-induced changes in bone mass and cortical bone geometry: A 12-month study in pre\/peri- and postmenarcheal tennis players","volume":"26","author":"Ducher","year":"2011","journal-title":"J Bone Miner Res"},{"key":"B9","article-title":"Mechanical basis of bone strength: Influence of bone material, bone structure and muscle action","volume":"17","author":"Hart","year":"2017","journal-title":"J Musculoskeletal Neuronal Interact"},{"key":"B10","doi-asserted-by":"publisher","DOI":"10.1007\/s11999-010-1702-0","article-title":"Methods for assessing bone quality: A review","volume":"469","author":"Donnelly","year":"2011","journal-title":"Clin Orthopaedics Related Res"},{"key":"B11","doi-asserted-by":"publisher","first-page":"13","DOI":"10.1159\/000103002","article-title":"The biomechanical basis of bone strength development during growth","volume":"51","author":"Kontulainen","year":"2007","journal-title":"Med Sport Sci"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.2217\/ijr.09.30","article-title":"The link between physical activity and bone strength across the lifespan","volume":"4","author":"Macdonald","year":"2009","journal-title":"Int J Clin Rheumatol"},{"key":"B13","doi-asserted-by":"publisher","DOI":"10.3389\/fendo.2021.704647","article-title":"The impact of diet and physical activity on bone health in children and adolescents","volume":"12","author":"Proia","year":"2021","journal-title":"Front Endocrinol"},{"key":"B14","doi-asserted-by":"publisher","DOI":"10.4103\/2230-8210.104040","article-title":"Assessing bone health in children and adolescents","volume":"16","author":"Levine","year":"2012","journal-title":"Indian J Endocrinol Metab"},{"key":"B15","doi-asserted-by":"publisher","DOI":"10.1542\/peds.2014-2173","article-title":"Optimizing bone health in children and adolescents","volume":"134","author":"Golden","year":"2014","journal-title":"Pediatrics"},{"key":"B16","doi-asserted-by":"publisher","DOI":"10.1016\/S1470-2045(08)70153-0","article-title":"Prevalence and clinical implications of sarcopenic obesity in patients with solid tumours of the respiratory and gastrointestinal tracts: A population-based study","volume":"9","author":"Prado","year":"2008","journal-title":"Lancet Oncol"},{"key":"B17","doi-asserted-by":"publisher","DOI":"10.1542\/peds.107.6.1387","article-title":"Physical activity and bone measures in young children: The Iowa bone development study","volume":"107","author":"Janz","year":"2001","journal-title":"Pediatrics"},{"key":"B18","doi-asserted-by":"publisher","DOI":"10.1016\/j.bone.2007.05.001","article-title":"Physical Activity and Femoral Neck Bone Strength during Childhood: The Iowa Bone Development Study","volume":"41","author":"Janz","year":"2007","journal-title":"Bone"},{"key":"B19","doi-asserted-by":"publisher","DOI":"10.1136\/bjsports-2014-093574","article-title":"Objectively measured physical activity trajectories predict adolescent bone strength: Iowa Bone Development Study","volume":"48","author":"Janz","year":"2014","journal-title":"Br. J Sports Med"},{"key":"B20","doi-asserted-by":"publisher","DOI":"10.1111\/j.1752-7325.2001.tb03369.x","article-title":"Patterns of fluoride intake from birth to 36 months","volume":"61","author":"Levy","year":"2001","journal-title":"J Public Health Dent"},{"key":"B21","doi-asserted-by":"publisher","first-page":"4","DOI":"10.1016\/j.ajcnut.2023.08.006","article-title":"Reference ranges for body composition indices by dual energy X-ray absorptiometry from the bone mineral density in childhood study cohort","volume":"118","author":"Zemel","year":"2023","journal-title":"Am J Clin Nutr"},{"key":"B22","doi-asserted-by":"publisher","DOI":"10.1016\/j.bone.2021.115882","article-title":"Effects of fluoride intake on cortical and trabecular bone microstructure at early adulthood using multi-row detector computed tomography (MDCT)","volume":"146","author":"Saha","year":"2021","journal-title":"Bone"},{"key":"B23","doi-asserted-by":"publisher","first-page":"9","DOI":"10.7150\/ijms.72233","article-title":"Association between the appendicular lean mass index or handgrip strength and bone mineral density in patients undergoing peritoneal dialysis","volume":"19","author":"Kang","year":"2022","journal-title":"Int J Med Sci"},{"key":"B24","doi-asserted-by":"publisher","DOI":"10.1002\/jbmr.4239","article-title":"Predictive value of DXA appendicular lean mass for incident fractures, falls, and mortality, independent of prior falls, FRAX, and BMD: Findings from the Women\u2019s Health Initiative (WHI)","volume":"36","author":"Harvey","year":"2021","journal-title":"J Bone Miner Res"},{"key":"B25","doi-asserted-by":"publisher","DOI":"10.1007\/s00198-015-3041-1","article-title":"A longitudinal study of bone area, content, density, and strength development at the radius and tibia in children 4-12 years of age exposed to recreational gymnastics","volume":"26","author":"Jackowski","year":"2015","journal-title":"Osteoporosis International: A J Established as Result Cooperation between Eur Foundation For Osteoporosis Natl Osteoporosis Foundation USA"},{"key":"B26","first-page":"3","article-title":"From mechanostat theory to development of the \u00abfunctional muscle-bone-unit\u00bb","volume":"5","author":"Schoenau","year":"2005","journal-title":"J Musculoskeletal Neuronal Interact"},{"key":"B27","doi-asserted-by":"publisher","DOI":"10.1016\/j.bone.2018.05.023","article-title":"Relative contributions of lean and fat mass to bone strength in young Hispanic and non-Hispanic girls","volume":"113","author":"Hetherington-Rauth","year":"2018","journal-title":"Bone"},{"key":"B28","doi-asserted-by":"publisher","DOI":"10.3389\/fped.2023.1226524","article-title":"Musculoskeletal health in children and adolescents","volume":"11","author":"Faienza","year":"2023","journal-title":"Front Pediatr"},{"key":"B29","doi-asserted-by":"publisher","DOI":"10.1002\/jbmr.3730","article-title":"Mechanical competence and bone quality develop during skeletal growth","volume":"34","author":"Zimmermann","year":"2019","journal-title":"J Bone Mineral Research: Off J Am Soc For Bone Mineral Res"},{"key":"B30","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2013.00371","article-title":"The effects of obesity on skeletal muscle regeneration","volume":"4","author":"Akhmedov","year":"2013","journal-title":"Front Physiol"},{"key":"B31","doi-asserted-by":"publisher","first-page":"67","DOI":"10.1007\/s12603-012-0004-5","article-title":"How to assess functional status: A new muscle quality index","volume":"16","author":"Barbat-Artigas","year":"2012","journal-title":"J Nutrition Health Aging"},{"key":"B32","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2021.643894","article-title":"Enhanced identification of novel potential variants for appendicular lean mass by leveraging pleiotropy with bone mineral density","volume":"12","author":"Peng","year":"2021","journal-title":"Front Immunol"}],"container-title":["Frontiers in Endocrinology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fendo.2026.1898386\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,14]],"date-time":"2026-08-14T04:23:23Z","timestamp":1786681403000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fendo.2026.1898386\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,14]]},"references-count":32,"alternative-id":["10.3389\/fendo.2026.1898386"],"URL":"https:\/\/doi.org\/10.3389\/fendo.2026.1898386","relation":{},"ISSN":["1664-2392"],"issn-type":[{"value":"1664-2392","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,14]]},"article-number":"1898386"}}