{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T02:35:09Z","timestamp":1772764509677,"version":"3.50.1"},"reference-count":46,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,11,14]],"date-time":"2025-11-14T00:00:00Z","timestamp":1763078400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biomolecules"],"abstract":"<jats:p>(1) Background: this study aimed to determine whether a serum parathyroid hormone (PTH) threshold of 40 pg\/mL represents a clinically relevant risk factor for vitamin D (VitD) deficiency and reduced bone mineral density (BMD). It also investigated potential genetic interactions influencing PTH regulation and skeletal health in patients with periodontitis. (2) Methods: a cross-sectional analysis was conducted on 1038 periodontitis patients (35\u201375 years). Serum PTH, VitD, calcium (Ca), phosphate (P), and urinary parameters were assessed. Dual-energy X-ray absorptiometry (DXA) was used to evaluate BMD in 261 subjects. Vitamin D Receptor (VDR) and estrogen receptor alpha (ER\u03b1) polymorphisms were genotyped, and composite genetic risk scores were calculated. Statistical analyses included correlation tests, subgroup comparisons, and regression models. (3) Results: sixty-two percent of individuals had PTH &gt; 40 pg\/mL, which was associated with significantly lower 25(OH)D and Ca levels and reduced T-scores (p &lt; 0.05). PTH levels negatively correlated with BMD (Pearson\u2019s r = \u20130.159, p = 0.0105). Patients with higher ER\u03b1 polymorphism scores showed increased PTH values (p &lt; 0.05), while VDR variants demonstrated a positive but no significant trend. (4) Conclusions: a PTH threshold of 40 pg\/mL identifies individuals at higher risk of VitD deficiency and skeletal fragility, even without overt hypercalcemia. Genetic factors, particularly ER\u03b1 variants, may contribute to elevated PTH levels, suggesting value in integrating biochemical, densitometric, and genetic screening for early bone health risk stratification.<\/jats:p>","DOI":"10.3390\/biom15111600","type":"journal-article","created":{"date-parts":[[2025,11,14]],"date-time":"2025-11-14T16:46:22Z","timestamp":1763138782000},"page":"1600","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Serum PTH \u2265 40 pg\/mL as a Marker of Bone Fragility and Vitamin D Deficiency in Periodontitis Patients: Biochemical, Densitometric and Genetic Evidence"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6611-8103","authenticated-orcid":false,"given":"Giada","family":"Marroncini","sequence":"first","affiliation":[{"name":"Biomolecular Diagnostic Laboratories, Via N. Porpora, 50144 Florence, Italy"},{"name":"Department of Clinical and Experimental Medicine, University of Florence, 50139 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4992-2252","authenticated-orcid":false,"given":"Serena","family":"Martinelli","sequence":"additional","affiliation":[{"name":"Department of Clinical and Experimental Medicine, University of Florence, 50139 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Francesco","family":"Petrelli","sequence":"additional","affiliation":[{"name":"Department of Biology, School of Pharmacy, University of Rome \u201cTor Vergata\u201d, 00133 Rome, Italy"},{"name":"Department of Biomedical Sciences, University of Lausanne, 1005 Lausanne, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Francesco","family":"Bombardiere","sequence":"additional","affiliation":[{"name":"Biomolecular Diagnostic Laboratories, Via N. Porpora, 50144 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Antonio","family":"Sarnataro","sequence":"additional","affiliation":[{"name":"Biomolecular Diagnostic Laboratories, Via N. Porpora, 50144 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Francesco Saverio","family":"Martelli","sequence":"additional","affiliation":[{"name":"Biomolecular Diagnostic Laboratories, Via N. Porpora, 50144 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,11,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1056\/NEJM199507273330407","article-title":"Calcium-ion-sensing cell-surface receptors","volume":"333","author":"Brown","year":"1995","journal-title":"N. Engl. J. 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