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NCT Number: NCT07788391

Vitamin D Status in Obstructive Sleep Apnea With and Without Comorbidities

This retrospective observational study evaluates the relationship between vitamin D status and obstructive sleep apnea (OSA) in adults. The study includes 269 participants divided into four groups: healthy controls, participants with simple snoring without OSA, patients with OSA without comorbidities, and patients with OSA with comorbidities.

The main objective is to compare serum 25-hydroxyvitamin D [25(OH)D] levels among these groups and to examine whether vitamin D status is associated with the presence and severity of OSA. Demographic characteristics, body mass index, laboratory measurements, and available overnight polysomnography findings are evaluated using existing medical records. The study also examines the distribution of vitamin D deficiency across the study groups and the relationship between vitamin D categories and OSA severity.

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Key information

Conditions

Vitamin D Deficiency Apnea Avitaminosis Deficiency Diseases Dyssomnias Malnutrition Nervous System Diseases Nutrition Disorders Nutritional and Metabolic Diseases Obstructive Sleep Apnea Respiration Disorders Respiratory Tract Diseases Sleep Apnea Syndromes Sleep Apnea, Obstructive Sleep Disorders, Intrinsic Sleep Wake Disorders

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Hisar Intercontinental Hospital

Istanbul, 34768, Turkey (Türkiye)

About this study

This retrospective comparative study evaluates serum 25-hydroxyvitamin D [25(OH)D] status across clinically distinct obstructive sleep apnea (OSA) phenotypes. Participants were classified into four groups: healthy controls, symptomatic participants with simple snoring/non-OSA (apnea-hypopnea index [AHI] <5 events/hour), patients with OSA without comorbidities, and patients with OSA with comorbidities. OSA was defined as AHI ≥5 events/hour and categorized as mild, moderate, or severe according to conventional AHI thresholds.

Among patients with OSA, comorbid OSA was defined by the presence of at least one documented chronic condition, including hypertension, diabetes mellitus, cardiovascular disease, dyslipidemia, or hypothyroidism. Demographic and anthropometric characteristics, serum 25(OH)D concentrations, available routine laboratory measurements, and polysomnographic parameters were retrospectively obtained from existing medical records and hospital databases.

The study compares vitamin D status across the four groups and evaluates whether serum 25(OH)D concentrations and vitamin D categories are associated with OSA severity. The study also explores whether differences in vitamin D status across OSA phenotypes persist after accounting for age, sex, and body mass index.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Adults aged 18 years or older. Participants with available serum 25-hydroxyvitamin D [25(OH)D] measurements. For PSG-evaluated groups, availability of overnight polysomnography data allowing classification according to the apnea-hypopnea index (AHI).

Participants meeting the predefined criteria for one of the study groups: healthy control, simple snoring/non-OSA, OSA without comorbidities, or OSA with comorbidities.

Exclusion criteria

Missing or insufficient data required for study-group classification. Missing serum 25(OH)D measurements. Incomplete polysomnographic data preventing determination of OSA status or severity in PSG-evaluated participants.

Treatment and study plan

Primary outcomes

  1. Serum 25-Hydroxyvitamin D Levels Across Study Groups

    Time frame: During the retrospective study period (2024-2026)

    Serum 25-hydroxyvitamin D [25(OH)D] concentrations were compared among healthy controls, simple snoring/non-OSA participants, patients with OSA without comorbidities, and patients with OSA with comorbidities.

Secondary outcomes

  1. Distribution of Vitamin D Status Across Study Groups

    Time frame: During the retrospective study period (2024-2026)

    Participants were categorized according to serum 25-hydroxyvitamin D [25(OH)D] concentrations as <20 ng/mL, 20-30 ng/mL, or >30 ng/mL. The distribution of these vitamin D categories was compared among healthy controls, simple snoring/non-OSA participants, patients with OSA without comorbidities, and patients with OSA with comorbidities.

Other outcomes

  1. Association of Vitamin D Status With Polysomnographic Severity of OSA

    Time frame: During the retrospective study period (2024-2026)

    The association of serum 25-hydroxyvitamin D [25(OH)D] status with polysomnographic severity of obstructive sleep apnea was evaluated using AHI and OSA severity categories (mild, moderate, and severe). Available polysomnographic parameters, including oxygen desaturation index (ODI) and minimum oxygen saturation (SpO₂), were also evaluated.

Sponsors and collaborators

Lead sponsor

Hisar Intercontinental Hospital

Other

Registry information

Official study title

Serum 25-Hydroxyvitamin D Across Obstructive Sleep Apnea Phenotypes With and Without Comorbidities: A Retrospective Comparative Study

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
Aug 26, 2026
Registry last updated
Aug 26, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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