Swedish Iodine in Pregnancy and Development in Children (SWIDDICH) Study

NCT02378246 | Active Not Recruiting

• 1 other identifier: 13031305
• Study Type: interventional
• Target: 1,337
• Locations: 1 country
• Sites: 4

Brief Summary

THE ULTIMATE GOAL of this project is to answer the question "In MILD IODINE DEFICIENCY (ID), should a tablet with vitamins and minerals, including 150 μg iodine/day be administered to pregnant women with a normal diet, to attain a normal cognitive development of the fetus or is there no cognitive deficit from mild ID and no extra iodine is needed?". To answer this question, the investigators planned a randomized, placebo-controlled trial of micronutrient supplementation during pregnancy in Sweden (SWIDDICH) with the follow-up of childrens' COGNITIVE DEVELOPMENT at 18 months, 3.5, 7 and 14 years. Iodine deficiency (ID) is associated with thyroid morbidity and, especially in children, with impaired cognitive development. Sweden introduced iodine fortification of table salt 1936 and mental retardation due to severe ID is eradicated. Is mild ID during pregnancy also eradicated? If not, is this of importance? A national study performed by the investigators in 2007 showed iodine sufficiency in general population, but there are no pregnancy data. Local studies have raised concerns for mild ID during pregnancy in Sweden and a trans-sectional national study is currently ongoing. The burning question for Sweden and the whole world is: is mild ID during pregnancy of importance for the developing brain of the fetus? Two large observational studies have shown association between mild ID during pregnancy and lower verbal IQ or educational performance at school-aged children. The world needs a randomized placebo-controlled trial (RTC) comparing the cognitive outcome in children exposed to mild ID during fetal life with children exposed to normal iodine levels during fetal life. Our HYPOTHESIS is that pregnant women in Sweden have mild ID and that children exposed to mild ID during fetal life have a lower cognitive development, compared to children to mothers taking daily tablet with vitamins and minerals, including 150 ug iodine during pregnancy. The MAIN AIM of the SWIDDICH trial is to determine if children exposed to deficient micronutrition including mild iodine deficiency (ID) during fetal life achieve worse cognitive development compared to children exposed to normal iodine status reached by maternal iodine supplementation.

Conditions

Thyroid Gland; Node; Pregnancy; Cognitive Developmental Delay

Keywords

Iodine; Double-Blind Method; Randomized Controlled Tria; Cognitive Development

Outcome Measures

Primary Outcomes (1)

• Intelligence quotient (IQ) at 3.5 years, WPPSI IV

  Wechsler Preschool and Primary Scale of Intelligence - Fourth Edition; IQ with sub-domains

  when the child is at the age of 3,5 years ± 2 months

Secondary Outcomes (50)

• Psychomotor development at 18 months, ASQ-3

  when the child is at the age of 18 months ± 1 month

• Intelligence quotient (IQ) at 7 years, WISC IV

  when the child is at the age of 7 years ± 3 months

• Intelligence quotient (IQ) at 14 years, WISC IV

  when the child is at the age of 14 years ± 6 months

• Behavioral problems at 3.5 years, CBCL

  when the child is at the age of 3,5 years ± 2 months

• Behavioral problems at 7 years, CBCL

  when the child is at the age of 7 years ± 3 months

Study Arms (2)

Tablet with vitamins and minerals, containing 150 ug iodine, 1 tablet daily

EXPERIMENTAL

Table of contents: Vitamin B2 1.4 mg, Vitamin B12 15 µg, Iron 12 mg, Zinc 12 mg, Iodine 150 µg, Selenium 50 µg, Calcium 250 mg

Dietary Supplement: Iodine

Placebo: non-iodine containing multivitamin, 1 tablet daily

PLACEBO COMPARATOR

Table of contents: Vitamin A 400 µg, Vitamin B1 1.4 mg, Vitamin B2 1.7 mg, Vitamin B6 1.8 mg, Vitamin B12 3 µg, Vitamin C 60 mg, Vitamin D 5 µg, Vitamin E 10 mg, Niacin 19 mg, Folic acid 200 µg

Dietary Supplement: Placebo

Interventions

Iodine DIETARY_SUPPLEMENT

Tablet with vitamins and minerals, containing 150 ug iodine, 1 tablet daily

Placebo DIETARY_SUPPLEMENT

Placebo: non-iodine containing multivitamin, 1 tablet daily

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Pregnant, week \<13
• Age 18-40 years
• Intent of a full term pregnancy
• Agreement of taking no iodide containing supplements during the study except for study supplement

You may not qualify if:

• Known current thyroid disease
• Risk factors for thyroid disease (history or heredity for thyroid, other autoimmune disease or symptoms of hypo-/hyperthyroidism) where the TSH is abnormal
• Possibility to not attend to the protocol according to the investigator's opinion
• Less than 6 months from previous pregnancy or lactating period
• Vegan
• CONTROL WOMEN
• Age 18-40 years
• Agreeing not to take iodide containing supplements 1 week prior to the collecting of the samples.
• Current thyroid disease
• Risk factors for thyroid disease (history or heredity for thyroid or other autoimmune disease or symptoms of hypo-/hyperthyroidism) where the TSH is abnormal
• Possibility to not attend to the protocol according to the investigator's opinion
• Currently pregnant or lactating
• Less than 6 months from previous pregnancy or lactating period
• Vegans

Sponsors & Collaborators

• Göteborg University: lead
• Sahlgrenska University Hospital: collaborator

Study Sites (4)

Umeå Universitet, Department of Clinical Sciences

Umeå, Västerbotten County, 901 85, Sweden

Location

Sahlgrenska University Hospital

Gothenburg, 413 45, Sweden

Location

Linköping University Hospital

Linköping, 581 85, Sweden

Location

Unknown Facility

Skövde, Sweden

Location

Related Publications (2)

• Manousou S, Eggertsen R, Hulthen L, Filipsson Nystrom H. A randomized, double-blind study of iodine supplementation during pregnancy in Sweden: pilot evaluation of maternal iodine status and thyroid function. Eur J Nutr. 2021 Sep;60(6):3411-3422. doi: 10.1007/s00394-021-02515-1. Epub 2021 Feb 23.

  PMID: 33620551 DERIVED

• Manousou S, Johansson B, Chmielewska A, Eriksson J, Gutefeldt K, Tornhage CJ, Eggertsen R, Malmgren H, Hulthen L, Domellof M, Nystrom Filipsson H. Role of iodine-containing multivitamins during pregnancy for children's brain function: protocol of an ongoing randomised controlled trial: the SWIDDICH study. BMJ Open. 2018 Apr 10;8(4):e019945. doi: 10.1136/bmjopen-2017-019945.

  PMID: 29643159 DERIVED

MeSH Terms

Conditions

Thyroid Diseases

Interventions

Iodine

Condition Hierarchy (Ancestors)

Endocrine System Diseases

Intervention Hierarchy (Ancestors)

Halogens; Elements; Inorganic Chemicals

Study Officials

• Helena Filipsson Nyström, Ass Prof

  Center for Endocrinology and Metabolism, SAhlgrenska University Hospital

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: January 19, 2015
• First Posted: March 4, 2015
• Study Start: November 1, 2012
• Primary Completion (Estimated): June 1, 2029
• Study Completion (Estimated): June 1, 2032
• Last Updated: August 26, 2025

Record last verified: 2025-03

Locations

SE (4)