The Genetic Effects on Vitamin D Supplementation

Study Overview
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Brief Summary
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Vitamin D is essential for skeletal growth and bone health, deficiency causes rickets and osteomalacia. In the UK 29% of adults have vitamin D deficiency. It is recommended all adults take 10µg vitamin D supplement daily. Genetic variations could alter vitamin D status by affecting vitamin D metabolism. Systematic reviews found variations in VDR, GC and CYP2R1 genes are associated with vitamin D deficiency. This study aims to assess the effects between vitamin D supplementation and variations in VDR, GC and CYP2R1 genes on vitamin D status.

Detailed Description
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The study design is a quantitative, randomised control trial measuring vitamin D concentrations in blood serum. All participants will be given the recommended 10µg daily dose of vitamin D supplementation. Participants will be grouped based on their genotype for each gene, as either low, medium or high-risk genotypes. The low-risk group will act as a control and the medium and high-risk groups will act as the intervention groups. Participants will attend St Mary's University's applied science laboratory twice. During their first visit participants will provide a 2ml capillary blood sample. Blood samples are collected using lancets to prick participants' ear lobes. The serum is extracted from the blood samples, serum is stored at -80c until analysis. Participants will be given 90 10µg vitamin D supplements and instructed to take one per day for 90 days. Participants will also be instructed to not make any major changes to their habitual diet. During the second visit participants will provide 1 ml of saliva sample into the Collection Pot and a second 2ml sample of blood. Serum samples will be analysed for vitamin D concentrations using 25(OH) Vitamin D ELISA kit. DNA will be extracted from the saliva samples using PSP SalivaGene DNA Kit following the manufacturer's protocol. DNA will be genotyped for variations in the VDR, GC and CYP2R1 genes. Data will be assessed to determine if variations in these genes influenced the effectiveness of vitamin D supplementation.

Official Title
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Effects of VDR rs7311856, GC rs2282679 and CYP2R1 rs2060793 Variants on Vitamin D Status: A Randomised Control Trial

Conditions
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Vitamin D Deficiency

Intervention / Treatment
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* Dietary Supplement: Vitamin D3 supplement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy adults female and male 18-65 years completion of physical activity readiness questionnaire (PAR-Q). Exclusion Criteria: Below 18 years above 65 years individuals taking medications that could interact with vitamin D status Individuals regularly taking daily Vitamin D supplementation during the 3 months before the intervention start date major dietary changes in vitamin D intake during the intervention period

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participants are grouped based on their genetic risk of vitamin D deficiency, all participants are given 10µg vitamin D supplements for 90 days
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Control (Low risk genotype)<br>Participants with no genetic variation in their VDR, GC and CYP2R1 genes that would increase their risk of vitamin D deficiency. Participants will be given 10µg vitamin D supplements for 90 days. This group is a control against the medium and high-risk intervention groups. | Dietary Supplement: Vitamin D3 supplement<br>* 10µg vitamin D3 supplement per day for 90 days<br>|
| Experimental: Intervention (Medium risk genotype)<br>Participants with genetic variation in their VDR, GC and CYP2R1 genes that moderately increase their risk of vitamin D deficiency. Participants will be given 10µg vitamin D supplements for 90 days. This group will be compared against the low-risk control group to determine the effect of genetic variations on vitamin D status. | Dietary Supplement: Vitamin D3 supplement<br>* 10µg vitamin D3 supplement per day for 90 days<br>|
| Experimental: Intervention (High risk genotype)<br>Participants with genetic variation in their VDR, GC and CYP2R1 genes that increase their risk of vitamin D deficiency. Participants will be given 10µg vitamin D supplements for 90 days. This group will be compared against the low-risk control group to determine the effect of genetic variations on vitamin D status. | Dietary Supplement: Vitamin D3 supplement<br>* 10µg vitamin D3 supplement per day for 90 days<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| vitamin D concentration | Effect between genetic variations and vitamin D concentration | 90 days |