Bone is a metabolically active tissue undergoing continuous remodeling through the coordinated actions of osteoclasts (resorption), osteoblasts (formation), and osteocytes (regulation). Under physiological conditions, bone formation and resorption are balanced and regulated by systemic hormones (PTH, vitamin D, estrogens) and local mediators. However, aging, metabolic disorders, physical inactivity, or pharmacological treatments may disrupt this equilibrium, leading to the predominance of one process over the other. Circulating biochemical markers of bone turnover-classified into formation markers (P1NP, osteocalcin, bone alkaline phosphatase) and resorption markers (CTx-I, NTx-I, DPD)-provide a means to monitor these dynamics. Beyond its mechanical role, bone also functions as an endocrine organ: osteocalcin, secreted by osteoblasts, modulates insulin secretion and sensitivity, linking bone to muscle and adipose tissue in the regulation of energy metabolism. Adipokines such as leptin and adiponectin further contribute to this complex crosstalk. Bone biomarkers are therefore essential for evaluating skeletal metabolism and identifying conditions such as osteoporosis, though the strict classification into formation versus resorption markers is limited, as some (e.g., osteocalcin) reflect both processes. This study aims to analyze IRCCS San Raffaele database records of urinary and serum biomarkers related to bone, muscle, and energy metabolism, to assess their trends and associations according to age and sex, and to develop statistical models capable of explaining their interrelationships.
Study Type
OBSERVATIONAL
Enrollment
1,000
IRCCS San Raffaele Hospital
Milan, Italy, Italy
RECRUITINGEvaluate circulating levels of osteocalcin, the main non-collagenous protein bound to hydroxyapatite (HAP) and synthesized by osteoblasts-thus considered a biomarker of bone formation-in relation to circulating vitamin D, an endocrine factor involved
Osteocalcin data will be acquired, retrospectively, through the San Raffaele Hospital database from January 1st, 2016 to November 30th, 2023
Time frame: As a retrospective study, data were obtained from the San Raffaele Hospital database for the period January 1, 2016, to November 30, 2023, regardless of patients' therapeutic paths.
As a secondary outcomes biomarkers of bone formation and reabsorption as well as biomarkers of skeletal muscle and energy metabolism will be evaluated in order to gain insights on how different tissues can influence each other.
The circulating levels of the following analytes will be analyzed to identify statistically significant associations between different biomarkers. Such associations may provide insights into how various tissues influence each other in relation to bone metabolism. Due to character limits in this form, a more detailed description cannot be provided. * Cross Linked C-telopeptide of Type I Collagen (CTx-I) * Alkaline phosphatase protein (ALP) * Urinary and serum creatinine * Urinary Pyridinoline * Calcium * Ionized calcium * Estrogen * Creatin kinase (CK) * Lactate dehydrogenase (LDH) * Potassium * Glucose * Glucagon * Insulin * Triglycerides * Total cholesterol * Parathormone * Thyrotropin * Thyroglobulin * Cortisol The International Standard Unit of measurment (SI units) will be adopted fot the above analytes. Data will be acquired, retrospectively, through the San Raffaele Hospital database from January 1st, 2016 to November 30th, 2023
Time frame: As a retrospective study, data were obtained from the San Raffaele Hospital database for the period January 1, 2016, to November 30, 2023, regardless of patients' therapeutic paths.
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