Correction of Selenium Deficiency Has Effect on Thyroid Function

Study Overview
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Brief Summary
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Previous literature has found potential association between selenium deficiency and inactivated glutathione peroxidase and deiodinase, which may contribute to subsequent elevation of T4 and ratio of T4/T3. Conduction of a case-control study (ID: Liuyanping3) has been applied on Clinicaltrials.gov to further elucidate effect of selenium deficiency on thyroid function. Based on its data, the investigators will perform a randomized, placebo-controlled,single-blinded crossover study on 20 participants with selenium deficiency to verify health consequence of selenium.

Official Title
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Correction of Selenium Deficiency Has Effect on Thyroid Function

Conditions
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Selenium Deficiency

Intervention / Treatment
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* Dietary Supplement: selenium supplementation
* Dietary Supplement: ordinary corn powder


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinical diagnosis of selenium deficiency through serum selenium test in previous phase (ID: Liuyanping3) of the study Should have stable body weight in the latest 3 months; Should be not prescribed with thyroid hormone replacement therapy Should be without medical history of thyroid surgery or iodine radiotherapy Should have normal FT3, FT4 and TSH. Exclusion Criteria: Clinical diagnosis of acute critical illness in the latest 1 year Have had weight fluctuation by more than 5% Eating disorders Neuropsychological disorders Allergy to corn or yeast

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: 20 participants with selenium deficiency (confirmed in previous phase (ID: Liuyanping3)) will be recruited to receive selenium-rich corn powder (20g/d, offering selenium 100μg/d) and ordinary corn powder (20g/d, offering selenium < 0.5μg/d ) in two different sequences (10 subjects each) with a four-week washout period.Plasma samples were obtained at different time points before and after administration of the selenium-rich corn powder and ordinary corn powder.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: A<br>Participants will be administered firstly selenium-rich corn powder 20g/d for 1 month and ordinary corn powder 20g/d for another month subsequently with a month washout period. | Dietary Supplement: selenium supplementation<br>* administration of selenium-rich corn powder 20g/d offering selenium 100μg/d<br>Dietary Supplement: ordinary corn powder<br>* ordinary corn powder,20g/d(selenium contain <0.5ug/20g).<br>* Other names: low selenium;|
| Placebo Comparator: B<br>Participants will be administered firstly ordinary corn powder 20g/d for 1 month and selenium-rich corn powder 20g/d for another month subsequently with a month washout period. | Dietary Supplement: selenium supplementation<br>* administration of selenium-rich corn powder 20g/d offering selenium 100μg/d<br>Dietary Supplement: ordinary corn powder<br>* ordinary corn powder,20g/d(selenium contain <0.5ug/20g).<br>* Other names: low selenium;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| comparison of thyroid function | comparison of thyroid function between administration of selenium supplementation and placebo | plasma sample will be collected at -1w/4w/8w/12w | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| comparison of serum selenium | comparison of serum selenium between administration of selenium supplementation and placebo | plasma sample will be collected at -1w/4w/8w/12w | 
| comparison of erythrocyte glutathione peroxidase activity | comparison of erythrocyte glutathione peroxidase activity between administration of selenium supplementation and placebo | plasma sample will be collected at -1w/4w/8w/12w | 
| comparison of serum deiodinase activity | comparison of serum deiodinase activity between administration of selenium supplementation and placebo | plasma sample will be collected at -1w/4w/8w/12w |