Polymorphisms in the Vitamin D System and Health
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Purpose
Polymorphisms in the vitamin D system appear to affect the serum 25(OH)D levels. If so one would expect these polymorphisms to be associated with vitamin D related conditions and diseases, which will be tested in the present study including DNA analyses in 9700 subjects
| Condition |
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Infarction Stroke Diabetes Fracture Aortic Stenosis Cancer Death |
| Study Type: | Observational |
| Study Design: | Time Perspective: Retrospective |
| Official Title: | Polymorphisms in the Vitamin D System and Health |
DNA from blood clots
| Estimated Enrollment: | 9700 |
| Study Start Date: | April 2011 |
| Estimated Study Completion Date: | July 2014 |
| Estimated Primary Completion Date: | October 2013 (Final data collection date for primary outcome measure) |
| Groups/Cohorts |
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myocardial infarction
subjects with myocardial infarction in the Tromsø study end point registry
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type 2 diabetes
subjects with type 2 diabetes in the Tromsø study end point registry
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stroke
subjects with stroke in the Tromsø study end point registry
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fracture
subjects with fracture in the Tromsø study end point registry
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cancer
subjects with cancer in the Tromsø study end point registry
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death
subjects registered as dead in the Tromsø study end point registry
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aortic stenosis
subjects with aortic stenosis in the Tromsø study end point registry
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control group
randomly selected controls from the Tromsø study
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Detailed Description:
Vitamin D, which is essential in calcium metabolism, is produced in the skin after sun exposure or obtained from food, mainly fatty fish or vitamin D supplements. For activation vitamin D must be hydroxylated in the liver to 25(OH)D and thereafter in the kidney to 1,25(OH)2D. In the circulation 25(OH)D and 1,25(OH)2D are bound to a carrier protein (DBP), and for 1,25(OH)2D to exert its effect it has to bind to the vitamin D receptor (VDR).
The serum level of 25(OH)D, which is the metabolite used to evaluate a person's vitamin D status, is in part genetically determined and several polymorphisms with effects on serum 25(OH)D have been identified. These polymorphisms, where the minor allele frequencies vary between 16 and 40 %, appear as important for the serum 25(OH)D level as the effect of season, physical activity or vitamin D supplementation.
Vitamin D is not only vital for the skeleton, but appears to be related to a number of health outcomes, including mortality as previously demonstrated in the Tromsø study. However, as the serum level of 25(OH)D is strongly influenced by life-style factors that are also related to health outcomes, it is difficult to decide whether the relation between vitamin D and health is causal or not.
On the other hand, the polymorphisms are not influenced by life-style, and the effect of the polymorphisms will be life-long. Accordingly, they may be a better marker of vitamin D status than a single serum 25(OH)D measurement. Furthermore, there are a number of polymorphisms regarding the vitamin D receptor (VDR) that may be associated with health.
In the present study we will therefore relate the polymorphisms affecting the serum 25(OH)D level and the function of the VDR, with anthropometric and biochemical measures, mortality, diseases and risk factors for disease. DNA will be obtained from the 4th Tromsø study.
If we find the expected associations between the polymorphisms and diseases, this will further strengthen the role of vitamin D in human health, and may be important for recommendations regarding vitamin D supplementation. Considering the high prevalence of vitamin D deficiency world wide, this may potentially have huge consequences for public health.
The main purpose of the present study is the vitamin D system, but in the Tromsø study we have previously also found a number of associations between thyroid and androgen function and health. Obtaining DNA for analysis will be the major cost in the project, whereas analyses of individual polymorphisms are relatively cheap. We will therefore also include polymorphisms regarding thyroid and androgen function.
Eligibility| Ages Eligible for Study: | 30 Years to 90 Years |
| Genders Eligible for Study: | Both |
| Accepts Healthy Volunteers: | Yes |
| Sampling Method: | Probability Sample |
Subjects from the fourth Tromsø study performed in 1994-1995 who had blood samples taken for later DNA analyses
Inclusion Criteria:
- participated in the fourth Tromsø study, later registered in our end point registry or selected as a control subject
Exclusion Criteria:
- lacking DNA sample
Contacts and Locations More Information
No publications provided by University of Tromso
Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
| Responsible Party: | Rolf Jorde, Professor, University of Tromso |
| ClinicalTrials.gov Identifier: | NCT01395303 History of Changes |
| Other Study ID Numbers: | UIT-ENDO-2011-2 |
| Study First Received: | July 14, 2011 |
| Last Updated: | October 29, 2012 |
| Health Authority: | Norway:National Committee for Medical and Health Research Ethics |
Keywords provided by University of Tromso:
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infarction stroke diabetes fracture aortic stenosis |
cancer death vitamin D androgens thyroid hormones |
Additional relevant MeSH terms:
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Aortic Valve Stenosis Constriction, Pathologic Death Diabetes Mellitus Fractures, Bone Infarction Stroke Heart Valve Diseases Heart Diseases Cardiovascular Diseases Ventricular Outflow Obstruction Pathological Conditions, Anatomical Pathologic Processes Glucose Metabolism Disorders Metabolic Diseases |
Endocrine System Diseases Wounds and Injuries Ischemia Necrosis Cerebrovascular Disorders Brain Diseases Central Nervous System Diseases Nervous System Diseases Vascular Diseases Vitamin D Ergocalciferols Vitamins Bone Density Conservation Agents Physiological Effects of Drugs Pharmacologic Actions |
ClinicalTrials.gov processed this record on May 23, 2013