Potential Preventive Effect of Selenium on Iodine-induced Thyroid Autoimmunity During Pregnancy

Summary

In 1994, the WHO and UNICEF Joint Committee on Health Policy recommended Universal Salt Iodization as a safe, cost-effective and sustainable strategy to ensure sufficient intake of iodine by all individuals. However, it is still absent in Latvia.

A recent countrywide study in 2013 shows iodine deficiency among pregnant women in Latvia: 81 % of pregnant women had UIC levels below the WHO recommended range of 150-250 mcg/g Cr.

Because mild to moderate iodine deficiency during pregnancy can adversely affect fetal brain development, WHO-UNICEF and ICCIDD advise an increase in the recommended daily dosage of iodine to 250 mcg/day for pregnant women and breastfeeding women and 150 mcg/day for women in the preconception period.

Data from a survey of the Latvian population indicate that approximately 100 mcg of iodine per day is consumed through foods and iodized salt. To meet the increased iodine requirement in pregnancy, pregnant women should take a supplement containing 150 mcg of iodine daily from the earliest time possible.

A sudden increase in iodine intake in an iodine-deficient population may increase thyroid autoimmunity. It is evident that thyroid disease has multiple adverse effects during pregnancy and in the developing fetus especially in women with elevated serum anti-thyroid antibody titers.

Studies have considered supplementing with selenium to reduce the risk of auto-immune thyroiditis/post-partum autoimmune thyroid disease. Of the 11 trials of selenium supplementation in patients with autoimmune thyroiditis, 7 have shown benefit with treatment for 6 months or longer.

Aim of study is to approve that 150 mcg of iodine daily improves iodine status in pregnant women and iodine 150 mcg in combination with selenium 100 mcg daily reduce risk of thyroid autoimmunity.

Hypothesis of study is that 150 mcg iodine daily during pregnancy improves iodine status. Iodine in combination with selenium is less associated with thyroid autoimmunity.

Study design: Pregnant women are randomized for either 150 mcg iodine intake daily or 150 mcg iodine combined with 100 mcg selenium daily. Interventional group is compared with controls without particular iodine supplementation.

Participants are asked to complete a questionnaire on dietary habits concerning iodine. Thyroid function (thyroid-stimulating hormone, free thyroxine) and thyroperoxidase antibodies (TPO-Ab) and urinary iodine are measured during first, second and third trimester of pregnancy and week 8 after delivery in both, intervention and control group.

Conditions

• Pregnancy
• Thyroid Autoimmune Disease
• Iodine Deficiency
• Selenium Deficiency

Interventions

DIETARY_SUPPLEMENT

Iodine

Receiving 150 μg iodine (as potassium iodide) daily

DIETARY_SUPPLEMENT

Iodine + Selenium

Receiving a combination of 150 μg iodine (as potassium iodide) and 100 μg selenium daily

Sponsors & Collaborators

• Latvian Biomedical Research and Study Centre

  collaborator OTHER_GOV

• Riga Maternity hospital

  collaborator UNKNOWN

• Latvian Institute of Organic Synthesis

  collaborator OTHER

• Riga Stradins University

  lead OTHER

Principal Investigators

• Ilze Konrade, professor · Riga Stradins University

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

QUADRUPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2018-01-05

Primary Completion

2018-12-31

Completion

2019-01-31

Countries

• Latvia

Study Locations