Vitamin D as an Endocrine Regulator of Bone and Muscle Health

Vitamin D is a central regulator of calcium–phosphate homeostasis and skeletal health, with additional roles in muscle biology and function. Through its hormonally active form, vitamin D regulates gene expression, interacts with parathyroid hormone and other endocrine pathways, and influences cellular processes involved in musculoskeletal development, maintenance, repair, and aging. Low vitamin D status is common worldwide and is associated with bone loss, fractures, muscle weakness, and sarcopenia, particularly among older adults and individuals with chronic or metabolic diseases. However, responses to supplementation vary according to baseline vitamin D status, calcium intake, population characteristics, underlying conditions, and dosing strategy.This Research Topic highlights advances in understanding vitamin D as an endocrine regulator of bone and muscle health. We welcome basic, translational, and clinical studies examining vitamin D biology, metabolism, deficiency, and responsiveness, alongside evidence-based approaches to assessment, supplementation, and treatment. The collection will also address ongoing questions surrounding optimal 25-hydroxyvitamin D [25(OH)D] thresholds, target concentrations, testing, and dosing across different populations. Particular emphasis will be placed on interactions between vitamin D and calcium–phosphate–PTH homeostasis, as well as altered vitamin D metabolism or resistance that may contribute to variation in musculoskeletal outcomes.We welcome contributions addressing, but not limited to, the following themes:• Associations between vitamin D status and bone density, remodeling, fracture risk, muscle health, and musculoskeletal aging • Effects of vitamin D supplementation according to baseline status, population characteristics, and clinical context • Endocrine, molecular, and cellular mechanisms linking vitamin D to bone and muscle function • Interactions between vitamin D and calcium–phosphate–PTH homeostasis • Vitamin D management in osteoporosis, sarcopenia, and metabolic bone disorders • Controversies surrounding 25(OH)D thresholds, target concentrations, testing, and dosing strategies • Altered vitamin D metabolism, vitamin D resistance, and variability in treatment response • Biomarkers and personalised approaches to improving clinical and musculoskeletal outcomes • Interactions between vitamin D, calcium intake, exercise, nutrition, and other musculoskeletal therapies Topic editors: Zhongjian Xie, Feng Xu Source: https://www.frontiersin.org/research-topics/84748/vitamin-d-as-an-endocrine-regulator-of-bone-and-muscle-health