Development and Internal Validation of a Clinical Risk Score for Hypovitaminosis D in Italian Adults Aged ≥50 Years Attending Osteoporosis and Metabolic Bone Disease Centers.

Authors

Ranuccio Nuti, Luigi Gennari, Bruno Frediani, Stefano Gonnelli, Daniela Merlotti, Carla Caffarelli, Giovanni Minisola, Antonino Catalano, Nazzarena Malavolta, Monica Pinto, Giulia Letizia Mauro, Vito Mascolo, Cristiano Maria Francucci, Vincenzo Vinicola, Anna Capozzi, Maria Punzo, Orazio Falla, Luca Dalle Carbonare, Serena Guiducci, Rosario Coltraro, Agostino Gaudio, Domenico Maria Carlucci, Alessandra Randazzo, Eleonora Mastria, Colin Gerard Egan, Mariangela Morelli, Giovanni Tripepi

Published in

Nutrients. Volume 18. Issue 17. Aug 27, 2026. Epub Aug 27, 2026.

Abstract

Background/Objectives: Hypovitaminosis-D is a highly prevalent condition worldwide, associated with adverse skeletal and extra-skeletal outcomes. Increasing demand for serum 25-hydroxyvitamin D (25(OH)D) testing points toward the need for simple tools to identify individuals at risk and optimize laboratory use. We aimed to develop and validate a clinical risk score for predicting hypovitaminosis-D based on easily assessable risk factors. Methods: This cross-sectional study included 1408 adults aged ≥50 years (1286 women and 122 men) attending centers across Italy dedicated to osteoporosis and metabolic bone diseases. Demographic, clinical, lifestyle, and dietary data were collected through a standardized questionnaire. Overall, 1147 subjects (81.5%) were receiving cholecalciferol supplementation. Univariable and multivariable logistic regression analyses identified predictors of 25(OH)D < 20 ng/mL (primary outcome) and <30 ng/mL. Risk scores were derived from models and internally validated. Discriminative ability was assessed using ROC curves, and calibration was conducted by comparing predicted and observed probabilities. Results: The median age was 67 years, and 91.3% were female. Median 25(OH)D was 33.2 ng/mL; 9.8% had levels < 20 ng/mL. Independent predictors of hypovitaminosis-D (25(OH)D < 20 ng/mL) included higher body mass index, residence in Northern Italy, reduced summer sun exposure, sunscreen use, cardiovascular disease, glucocorticoid use, absence of cholecalciferol supplementation, and no prior vitamin D use. The score (range 9-18) showed good discrimination (Area under the curve; AUC: 79.1%, 95% CI: 75.3-82.9) and calibration (r = 0.98, p < 0.001). A screening cut-off (10.3-10.7) ensured high sensitivity (87.0-92.7%), while 11.9-12.0 balanced sensitivity (~62%) and specificity (~80%). A second score for 25(OH)D < 30 ng/mL showed moderate discrimination (AUC: 69.6%). Performance remained stable across seasons and in untreated subjects (AUC: 72.7%). Female predominance, widespread vitamin D use, and the absence of external validation or impact analyses limit generalizability. Conclusions: The proposed data-driven clinical risk score may help identify individuals at risk of vitamin D deficiency and support targeted screening strategies, potentially reducing unnecessary testing in routine clinical practice.

PMID:
42738977
Bibliographic data and abstract were imported from PubMed on 15 Sep 2026.

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