Vitamin D DeficiencyNCT07788391
Vitamin D Status in Obstructive Sleep Apnea With and Without Comorbidities
An observational study of Vitamin D Deficiency and Obstructive Sleep Apnea, run by Hisar Intercontinental Hospital at 1 site in Turkey (Türkiye).
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Vitamin D Deficiency, Obstructive Sleep Apnea
- How many people
- 269 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Jan 2024to 20 Apr 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: The study population consisted of adults evaluated at Hisar Intercontinental Hospital between 2024 and 2026. Participants included a healthy control group and adults who underwent overnight polysomnography because of symptoms suggestive of sleep-disordered breathing. PSG-evaluated participants were classified as simple snoring/non-OSA (AHI <5 events/hour), OSA without comorbidities, or OSA with comorbidities. The final study population included 269 participants: 81 healthy controls, 49 non-OSA participants, 50 patients with non-comorbid OSA, and 89 patients with comorbid OSA.
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Hisar Intercontinental Hospital
Istanbul, Istanbul, 34768
About this study
Official title: Serum 25-Hydroxyvitamin D Across Obstructive Sleep Apnea Phenotypes With and Without Comorbidities: A Retrospective Comparative Study
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.
Read the detailed description
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.
- Conditions
- Vitamin D Deficiency, Obstructive Sleep Apnea
- Keywords
- Obstructive Sleep Apnea, 25-Hydroxyvitamin D, Polysomnography, Apnea-Hypopnea Index, Vitamin D Deficiency
- Medical subject headings
- Vitamin D Deficiency, Sleep Apnea, Obstructive
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Healthy Controls | Individuals without documented obstructive sleep apnea or the predefined comorbid conditions, included as the healthy reference group. No study-specific intervention was assigned. | |
| Simple Snoring / Non-OSA | Symptomatic participants who underwent polysomnography and had an apnea-hypopnea index (AHI) <5 events/h. No study-specific intervention was assigned. | |
| OSA Without Comorbidities | Participants with OSA (AHI ≥5 events/h) without documented hypertension, diabetes mellitus, cardiovascular disease, dyslipidemia, or hypothyroidism. No study-specific intervention was assigned. | |
| OSA With Comorbidities | Participants with OSA (AHI ≥5 events/h) and at least one documented comorbid condition, including hypertension, diabetes mellitus, cardiovascular disease, dyslipidemia, or hypothyroidism. No study-specific intervention was assigned. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Serum 25-Hydroxyvitamin D Levels Across Study Groups
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.
Measured: During the retrospective study period (2024-2026)
Secondary outcomes (1)
Distribution of Vitamin D Status Across Study Groups
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.
Measured: During the retrospective study period (2024-2026)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Aug 2026
- Study start1 Jan 2024
- Primary completion20 Apr 2026
- Study completion20 Apr 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Vitamin D DeficiencyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 269 participants (actual)
Sponsor and investigators
- Lead sponsor
- Hisar Intercontinental Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Bekir Sami Uyanık, Hisar Intercontinental Hospital
- Investigators
- Bekir Sami Uyanık, MD, Prof. Dr., Principal investigator, Hisar Intercontinental HospitalOrhan Dalkılıç, MD, Assistant Professor, Principal investigator, Hisar Intercontinental Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07788391
- Sponsor's protocol ID
- 26-78
- Status last verified
- Aug 2026
- First submitted
- 23 Aug 2026
- Last updated
- 26 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be publicly shared because the study is based on retrospective clinical and laboratory records containing potentially sensitive patient information. De-identified data may be made available from the corresponding author upon reasonable request and subject to institutional and ethical approval.
Study at a glance
From the registry record, last updated by the sponsor on 26 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Serum 25-Hydroxyvitamin D Across Obstructive Sleep Apnea Phenotypes With and Without Comorbidities: A Retrospective Comparative Study
- ClinicalTrials.gov ID
- NCT07788391
- Acronym / sponsor ID
- 26-78
- Conditions
- Vitamin D Deficiency, Obstructive Sleep Apnea
- Keywords
- Obstructive Sleep Apnea, 25-Hydroxyvitamin D, Polysomnography, Apnea-Hypopnea Index, Vitamin D Deficiency
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 269 participants (actual)
- Lead sponsor
- Hisar Intercontinental HospitalUniversity, hospital or other
- Study start
- 1 Jan 2024 (actual)
- Primary completion
- 20 Apr 2026 (actual)
- Study completion
- 20 Apr 2026 (actual)
- First posted
- 26 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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.
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Healthy Controls | – | –Individuals without documented obstructive sleep apnea or the predefined comorbid conditions, included as the healthy reference group. No study-specific intervention was assigned. |
| Simple Snoring / Non-OSA | – | –Symptomatic participants who underwent polysomnography and had an apnea-hypopnea index (AHI) <5 events/h. No study-specific intervention was assigned. |
| OSA Without Comorbidities | – | –Participants with OSA (AHI ≥5 events/h) without documented hypertension, diabetes mellitus, cardiovascular disease, dyslipidemia, or hypothyroidism. No study-specific intervention was assigned. |
| OSA With Comorbidities | – | –Participants with OSA (AHI ≥5 events/h) and at least one documented comorbid condition, including hypertension, diabetes mellitus, cardiovascular disease, dyslipidemia, or hypothyroidism. No study-specific intervention was assigned. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- The study population consisted of adults evaluated at Hisar Intercontinental Hospital between 2024 and 2026. Participants included a healthy control group and adults who underwent overnight polysomnography because of symptoms suggestive of sleep-disordered breathing. PSG-evaluated participants were classified as simple snoring/non-OSA (AHI <5 events/hour), OSA without comorbidities, or OSA with comorbidities. The final study population included 269 participants: 81 healthy controls, 49 non-OSA participants, 50 patients with non-comorbid OSA, and 89 patients with comorbid OSA.
Key inclusion criteria (2 listed)
- 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.
Key exclusion criteria (1 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
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.
1 secondary outcome
Distribution of Vitamin D Status Across Study Groups
Time frame: During the retrospective study period (2024-2026)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Aug 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be publicly shared because the study is based on retrospective clinical and laboratory records containing potentially sensitive patient information. De-identified data may be made available from the corresponding author upon reasonable request and subject to institutional and ethical approval.
Related trials for Vitamin D Deficiency
Not yet recruitingPhase 2
REducing Systemic Inflammation With LOw-dose Colchicine to ImproVE Cardiovascular Calcification in Chronic Kidney Disease: A Pilot Randomized Open-Label Trial
Chronic Kidney Disease Mineral and Bone Disorder, Cognitive Function
Recruiting
Role of Vitamin D Supplementation in Children With Irritable Bowel Syndrome
Irritable Bowel Syndrome (IBS), Vitamin D Deficiency
RecruitingObservational study
Post Marketing Surveillance Study to Observe Safety and Effectiveness of CRYSVITA® in S. Korean Patients
FGF23-related Hypophosphataemic Rickets and Osteomalacia
Not yet recruiting
Effect of Vitamin D Supplementation Added to Iron Therapy in Children With Iron Deficiency Anemia
Iron Deficiency Anemia
RecruitingObservational study
A Natural History Study of Bone and Mineral Disorders
Tumor Induced Osteomalcia, Osteomalacia
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Bekir Sami Uyanık, MD, Prof. Dr. principal investigator
Hisar Intercontinental Hospital
Orhan Dalkılıç, MD, Assistant Professor principal investigator
Hisar Intercontinental Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Vitamin D Deficiency and Obstructive Sleep Apnea, run by Hisar Intercontinental Hospital at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 26 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Serum 25-Hydroxyvitamin D Levels Across Study Groups (time frame: During the retrospective study period (2024-2026)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Aug 2026.