Iodine Status in Swedish Lactating Women - Effect of Iodine Supplementation in the Thyroid Function of Mother and Infant
Information source: Göteborg University
ClinicalTrials.gov processed this data on August 23, 2015 Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Thyroid Gland; Node; Lactation
Intervention: iodine (Dietary Supplement); Placebo (Dietary Supplement)
Phase: N/A
Status: Recruiting
Sponsored by: Göteborg University Official(s) and/or principal investigator(s): Helena Filipsson Nyström, Ass Prof, Principal Investigator, Affiliation: Center for Endocrinology and Metabolism, SAhlgrenska University Hospital, göteborg, Sweden
Overall contact: Sofia Manousou, PhD student, Phone: +46700595310, Email: sofia.manousou@vgregion.se
Summary
The aim of the study is to measure urinary milk iodine concentration (MIC), iodine
concentration (UIC), thyroid hormones (TSH, FT4) and thyroperoxidase antibodies (TPOab) in
breast-feeding women, and UIC in their nursing infants to determine if the levels are
adequate, and to see how they can be influenced by 150 ug daily iodine supplementation in
breast-feeding women. The hypothesis is that there is a relative iodine deficiency in this
sub-population - lactating women and nursing child, and that this can be influenced by
iodine supplementation. Adequate thyroid hormone and iodine levels are very important for
small children, when the plasticity of the brain is greatest.
This is as a prospective, double-blind, placebo-controlled study of 200 mothers and their
infants. In parallel, 90 age-matched healthy non-pregnant women are recruited. Mothers are
randomized to 150 µg/day iodide supplementation or placebo.
Pregnant women are asked for participation on a visit in pregnancy week 35, at the mother
health care (MVC) at Mölnlycke and Skövde. The study will run for approximately 6 months for
each individual and begins by sampling 1 (UIC, TSH, FT4, TPOab) at week 37 of the pregnancy.
One week after birth, when the sample 2 is collected (as above inclusively MIC), women get
randomized to 150 µg iodine or placebo. New sampling 3 (UIC, TSH, FT4, MIC ) and 4 (same as
sampling 2) is collected after 3 and 6 months respectively. 6 months after birth the study
is completed for every individual. In parallel, 90 healthy non-pregnant, non-lactating women
in the same age range are recruited and followed with UIC, TSH, FT4, TPOab for 6 months as a
control group. In each case a simple questionnaire is filled and blood is also frozen for
future analyses .
Clinical Details
Official title: A Double-blinded Randomised Study of Iodine Supplementation to Lactating Women in an Iodine-sufficient Area in Sweden and Evaluation of Maternal and Neonatal Iodine Levels and Thyroid Function
Study design: Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Outcomes Assessor), Primary Purpose: Prevention
Primary outcome: milk iodine concentrationmilk iodine concentration milk iodine concentration urinary iodine concentration in the infant urinary iodine concentration in the infant urinary iodine concentration in the infant
Secondary outcome: TSH in the motherTSH in the mother TSH in the mother TSH in the mother FT4 in the mother FT4 in the mother FT4 in the mother FT4 in the mother TPOab in the mother TPOab in the mother TPOab in the mother urinary iodine concentration in the mother urinary iodine concentration in the mother urinary iodine concentration in the mother urinary iodine concentration in the mother
Detailed description:
Are the mothers to be treated with 150 µg iodide per day during lactation to guarantee
normal intake of iodine in breast-milk (MIC) and normal urinary iodine concentration (UIC)
in their off-spring?
Purpose and Aim This prospective, placebo-controlled study focus on the question whether
lactating mothers shall add 150 µg iodide po to guarantee normal MIC and UIC levels in their
children or not, as current iodinating program does not guarantee normal levels in these
subgroups
- Primary aim: To compare the MIC and UIC of the children to lactating mothers receiving
150 µg iodide or receiving placebo and compare to WHO recommendations.
- Secondary aim: To study UIC in the mothers during lactation compared to controls To
study the frequency of thyroid dysfunction in lactating women and whether it differs
among patients on 150 µg or placebo.
If the UIC concentration in the children breast fed by mothers receiving placebo is lower
than the recommended levels by the WHO and if these levels are normalized with 150 µg iodide
to the mother this study will be the supportive study for national authorities in Sweden,
Europe and in the word to recommend all lactating mothers to add 150 µg when breast feeding
even if the country is judged iodine sufficient.
Survey of the field Iodine deficiency in the nature affects thyroid function The supply of
iodine varies in different parts of the world, mainly because of varying levels of iodine in
the ground water, different soils and plants, different distribution of sea-food, and
dissimilar diary food consumption. In many areas with depleted soils and a long distance to
the sea, iodine deficiency (ID) is still a major health problem.
Adequate dietary iodine intake is essential for the production of thyroid hormones. Low
iodine intake results in the development of hypothyroidism and goiter. Impaired production
of thyroid hormones during pregnancy affects growth and brain development in the progeny.
Iodine deficiency in school-age children impairs somatic growth, cognitive performance and
motor function.
Iodine insufficiency outside Sweden Iodine deficiency remains a public health problem in 47
countries worldwide. Although most countries worldwide have implemented universal salt
iodization , countries like Australia, New Zealand and several European countries have been
reporting reoccurring iodine deficiency. Changes in food consumption patterns, legislation
not covering processed food and decreased salt consumption impose new challenges in ensuring
adequate iodine nutrition in the population.
Iodine sufficiency in Sweden In Sweden, goitre was first described by Carl von Linné in
1747, and in the beginning of the 20th century, goitre was detected in 60% of cases in
certain areas (19) and in 18% of the total population . A national survey conducted in 1929
confirmed endemic goitre regions located in the inner or eastern part of the country: these
iodine deficient areas were known as the "goitre-belt".
These observations contributed to initiation of the Swedish national iodine fortification
program for salt in 1936. Initially, 10 mg of potassium iodide (KI) was added to every
kilogram salt. In 1966, this was increased to the current level of 50 mg/kg salt, as goitre
was still prevalent in some regions of the country.
The first national evaluation of iodine status in Sweden was performed by our group
according to the recommendations of the World Health Organization (WHO). Urinary iodine
concentration (UIC) was measured in a representative national sample of children aged 6-12
years: the national median UIC was 125 μg/L, indicating optimal iodine nutrition . However,
thyroid volumes were higher in Swedish school children than in the international reference
study, which may be an effect from genetic and other environmental factors. Iodine intake is
considered optimal in Sweden. These findings underline the importance of regular monitoring
of iodine intake, especially concerning the decreased intake of table salt that is likely to
follow health campaigns and patients with higher need of iodine may be at risk.
Iodine demands increase during pregnancy and lactating The need of iodine is increased
during pregnancy and lactating because of the increased thyroid hormone production and
enrichment of iodine in breast-milk. An intake of iodide during pregnancy and breast feeding
of 250 µg is recommended compared to 150 µg/day in the normal population. Severe iodine
deficiency in the new-borne results in cretinism.
The most critical period except for the prenatal period for the child is the two first years
of life when the brain still develops. An enhanced risk period is the first 6 month of life
when the child is breast-feeding. During this period the child is depending on the iodine
concentration in the milk, which is a direct consequence of the mother iodine nutrition.
When the infant starts to eat, iodide is supplied from the food.
Numerous studies have measured both thyroid hormones and MIC in women living in iodine
sufficient and insufficient regions, which are summarized in three reviews . Three studies
have evaluated iodine nutrition in infants longitudinally , whereas the most recent from New
Zealand is the longest; during 6 months maternal and infant iodine status were measured.
In the world and the communities of thyroid disease the question is debated whether or not
iodide shall be given to pregnant women. American thyroid Association (ATA) has made a
strong recommendation for this in fear the even mild iodine deficiency in small children may
affect the brain development negatively. WHO has modified their guidelines of
supplementation to whether the nation is regarded iodine sufficient, including sufficient
levels in pregnant and lactating women (category 1), where no iodide supplementation is
need, or not sufficient. The latter group is divided in two; one group where most patient,
but <90%, eat iodinated salt and UIC <100 (category 2) and one group with similarly low UIC
but where iodized salt is scarcely used (category 3). An iodine supplement of 150 µg is the
recommendation in these countries. However, in 2010 Mulrine et al performed a placebo
controlled study the first 6 months postpartum. The mothers were iodine deficient, as New
Zealand had not implemented an iodizing program, and were supplemented with 75 or 150
µg/day. Both mother and child had UIC and MIC lower than recommend by the WHO. The authors
encourage a study done in the circumstances of iodine sufficiency in the nation.
Data from pregnant and lactating women in Sweden are scares. Two small local studies reports
median UIC 145-178 µg/dag and 89 µg/l during pregnancy. More knowledge is needed to judge
if Swedish woman shall have and iodine supplementation of 150 µg/day or not during this
vulnerable period of life for their children.
Project description Study design This is a prospective, double-blinded placebo-controlled
trial of 200 lactating women and their children. Mother is randomized to 150 µg/day iodide
supplementation or placebo for 26 weeks. In parallel 90 healthy female controls are
recruited from the same community stratified for age and smoking habits. Patients are
included after week 36 in pregnancy by the midwife and UIC is collected in the mothers and
thyroid hormones levels and thyroperoxidase antibodies (TPO-ab) are assessed and a simple
questionnaire is filled in. Placebo/iodide is started in the mothers at the 1 week visit
(7±3 days) at the child care centre postpartum. At this visit UIC is collected in the
mother, child and control, MIC is measured in breast milk and similar thyroid hormones and
TPO-ab are assessed in controls that also are included at this visit. The simple
questionnaire is repeated in adults. At the visits 13 (13±1) and 26 (26±1) weeks postpartum
UIC samples is collected in all and MIC is measured in those who still breast-feed. In
mothers and control women thyroid hormones and the simple questionnaire is filled in. TPO-ab
is collected in adults at the last visit. At all occasion blood specimens are taken, blood
is also frozen for future analyses. Weight and length are registered postnatal in the child.
Study population Patients At the antenatal care unit at Mölnlycke Health Care center 200
pregnant women aged 18-40 years will be collected consecutively according to inclusion and
exclusion criteria.
Inclusion criteria: Pregnant ≥36 weeks, Singleton pregnancy, Aged 18-40 years, Intend to
breast-feed, Agree to take no iodine containing supplements during the study postpartum
except for study medication, No current thyroid disease Exclusion criteria: Patient who may
not attend to the protocol according to the investiga¬tor's opinion, Plans of another
pregnancy within the first 6 months postpartum, Vegans
Controls Controls are collected from a randomized sample attain by the Swedish Tax Agency of
premenopausal women from Mölnlycke community. Controls in the same age as the patients are
contacted by mail for participation in the study and if smoking habits agree with the
corresponding patient they come for an inclusion visit. If interested, the controls are told
to stop any other iodine containing supplements 1 week before the first visit. If no answer,
a reminding letter is sent after two weeks.
Inclusion criteria: Aged 18-40 years, Agree to take no iodine containing supplements during
the study postpartum. No current thyroid disease Exclusion criteria: Controls who may not
attend to the protocol according to the investiga¬tor's opinion, Plans pregnancy within the
next 6 months, Vegans
Activity plan, time schedule and significance Patients and controls are recruited in
parallel. Last patient/control visit day are in the spring 2017 and management of data and
publication during 2018-2019. If the study proves that supplement of 150 µg iodine to
mothers guarantee normal iodine intake in the newborn child contact will be taken with the
National Food Agency, the National Board Health and Social welfare and the government to
lobbying for a general directives of iodine supplementation to all lactating women.
Eligibility
Minimum age: 18 Years.
Maximum age: 40 Years.
Gender(s): Female.
Criteria:
LACTATING WOMAN:
Inclusion Criteria:
- 18-40 years.
- Pregnancy longer than week 36.
- Single Pregnancy.
- Planned breastfeeding.
- No current thyroid disease.
- Agree not to take iodine supplementation except as provided through the study.
Exclusion Criteria:
- Patient who is not expected to adhere to the research protocol. Plans for pregnancy
within 6 months after delivery.
- Vegans.
CONTROL WOMAN:
Inclusion Criteria:
- 18-40 years.
- No current thyroid disease.
- Agree not to iodine supplementation during the study.
Exclusion Criteria:
- Patient who is not expected to adhere to the research protocol.
- Plans for pregnancy within 6 months of study entry.
- Vegans.
Locations and Contacts
Sofia Manousou, PhD student, Phone: +46700595310, Email: sofia.manousou@vgregion.se
Health Care center, Mölnlycke SE-435 30, Sweden; Recruiting Mille Milakovic, MD, PhD, Phone: +4610-473 36 10, Email: mille.milakovic@vgregion.se Robert Eggertsen, Prof, Phone: +46708782250, Email: robert.eggertsen@vgregion.se Sofia Manousou, PhD student, Sub-Investigator Mille Milakovic, PhD, MD, Sub-Investigator Robert Eggertsen, Prof, Sub-Investigator Lena Hulthén, Prof, Sub-Investigator Helena Filipsson Nyström, Ass prof, Principal Investigator
Additional Information
Starting date: October 2011
Last updated: March 3, 2015
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