{
  "abstract": "Obesity is commonly accompanied by low circulating 25-hydroxyvitamin D [25(OH)D], potentially because of volumetric dilution, adipose distribution, and obesity-related changes in 25(OH)D metabolism. Parathyroid hormone (PTH) and 25(OH)D are linked through calcium–phosphate homeostasis and renal conversion of 25(OH)D to calcitriol, but whether 25(OH)D statistically accounts for the association between PTH and adiposity remains uncertain. The data derived from the baseline visit of 4822 participants Tehran Obesity Treatment Study was used to examine the relationship between PTH and 25(OH)D with obesity using regression models. Furthermore, a mediation analysis using potential-outcomes framework was carried out using the aforementioned factors to obtain direct effect of PTH and mediated effect of 25(OH)D on body mass index (BMI) and waist circumference (WC). Higher PTH and lower 25(OH)D were associated with greater adiposity. Compared with the lowest PTH category, PTH > 72.8 pg/mL was associated with 1.89 kg/m2 higher BMI, higher odds of morbid obesity (odds ratio: 1.66, 95% confidence interval: 1.33–2.09), and 1.67 cm greater WC. Compared with 25(OH)D < 12 ng/mL, concentrations > 35 ng/mL were associated with 1.81 kg/m2 lower BMI, lower odds of morbid obesity (odds ratio: 0.60, 95% confidence interval: 0.48–0.75), and 3.30 cm lower WC. For a PTH increase from 10 to 65 pg/mL, 25(OH)D mediated 7% of the total association with BMI and 9% with WC. Higher PTH and lower 25(OH)D were associated with BMI and WC. Exploratory decomposition suggested that circulating 25(OH)D accounted for only a small portion of the PTH–adiposity association. These findings support careful preoperative mineral-metabolism phenotyping and evaluation of abnormal PTH, but do not establish direction or causality within this framework.",
  "abstract_shown": true,
  "affiliations": [
    "Student Research Committee, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran",
    "Neuroscience Research Center, Iran University of Medical Sciences, Tehran, Iran",
    "Obesity Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran",
    "Tehran Obesity Treatment Center, Department of Surgery, Faculty of Medicine, Shahed University, Tehran, Iran",
    "Clinical Research and Development Center, Department of Nephrology, Shahid Modarres Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran",
    "Department of Community Medicine, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran",
    "Non-communicable Diseases Research Center, Alborz University of Medical Sciences, Karaj, Iran."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Sepehr Aghajanian",
      "orcid": "0000-0002-2149-632X"
    },
    {
      "affs": [
        2
      ],
      "name": "Maryam Barzin"
    },
    {
      "affs": [
        0
      ],
      "name": "Safa Saleh Nia"
    },
    {
      "affs": [
        0
      ],
      "name": "Fateme Mohammadifard",
      "orcid": "0009-0006-1419-1823"
    },
    {
      "affs": [
        2
      ],
      "name": "Majid Valizadeh"
    },
    {
      "affs": [
        3
      ],
      "name": "Alireza Khalaj"
    },
    {
      "affs": [
        4
      ],
      "name": "Amirhesam Alirezaei",
      "orcid": "0000-0001-9720-6723"
    },
    {
      "affs": [
        5,
        6
      ],
      "name": "Mahmood Bakhtiyari"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/eh1ypn583n59k.bib",
  "cited_by": 0,
  "doi": "10.1097/md.0000000000051362",
  "fulltext_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13727271/?tool=EBI",
  "id": "eh1ypn583n59k",
  "issns": [
    "0304-5412",
    "1536-5964",
    "0025-7974"
  ],
  "landing_url": "https://europepmc.org/article/PMC/PMC13727271",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "4300"
    ],
    [
      "heading",
      "Observational Study"
    ],
    [
      "heading",
      "Research Article"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13727271/pdf/?tool=EBI",
  "pmcid": "PMC13727271",
  "pmid": null,
  "published": "2026-10-30",
  "publisher": "Wolters Kluwer Health",
  "ris": "https://research.draconitic.com/paper/eh1ypn583n59k.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T15:20:51Z",
      "native_id": "PMC:PMC13727271",
      "source": "europepmc",
      "url": "https://europepmc.org/article/PMC/PMC13727271"
    },
    {
      "first_seen": "2026-11-05T12:23:23Z",
      "native_id": "PMC13727271",
      "source": "pmc",
      "url": "https://doi.org/10.1097/md.0000000000051362"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "journal-openalex:F27",
      "subfield": "general"
    }
  ],
  "title": "Parathyroid hormone, vitamin D, and general and abdominal adiposity in bariatric surgery candidates : A cross-sectional analysis of the Tehran Obesity Treatment Study",
  "title_text": "Parathyroid hormone, vitamin D, and general and abdominal adiposity in bariatric surgery candidates : A cross-sectional analysis of the Tehran Obesity Treatment Study",
  "type": "peer-reviewed",
  "updated_at": "2026-11-06T12:22:59Z",
  "url": "https://research.draconitic.com/paper/eh1ypn583n59k",
  "venue": "Medicine",
  "versions": []
}