Preconception Maternal Iodine Status and Offspring Cognitive Function:

Study Overview
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Brief Summary
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Little is known about maternal iodine nutrition before conception and its relation with the child's cognitive function. Using samples and data from the Southampton Women's Survey, iodine measurements from urine collected before the mothers became pregnant will be related to cognitive function measures in the children at age 6-7 years.

Detailed Description
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Adverse effects of severe maternal iodine deficiency in pregnancy on fetal brain development are well-established, but the effects of mild or moderate deficiency are not well understood. To date, most studies have examined iodine status in pregnancy; less is known about maternal iodine nutrition before conception, and this study aims to address that gap in information The Southampton Women's Survey (SWS) is a prospective study of mothers and children, established in 1998. A general population sample of 12,583 non-pregnant women, aged 20-34 years resident in Southampton was recruited (1998-2002). All women were visited at home by a research nurse and characterised in detail, including assessments of diet, lifestyle and body composition. Between 1998 and 2007, 3158 of the SWS women became pregnant, and went on to deliver a live singleton infant. These women were followed up in through pregnancy and their children have been assessed in a number of follow-up studies in infancy and childhood. These have included repeated assessments of diet, anthropometry and body composition, as well as detailed functional measurements at specific ages, and are ongoing. At the 6-7 year assessment, the children's cognitive function was measured and this is the primary outcome. Spot urine samples were collected from the SWS women at clinic visits following their initial interviews (median 33 (IQR 15-87) days), in the period before conception. The time of day was recorded for each urine collection. Urine samples were split divided into aliquots on the day of collection. They were frozen and stored at -80⁰oC from the date of collection until being thawed and assayed for iodine and creatinine contents in 2016 by the Trace Element Unit, Southampton General NHS Trust Hospital, Southampton, UK.

Official Title
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Preconception Maternal Iodine Status and Offspring Cognitive Function: Longitudinal Analyses in the Southampton Women's Survey

Conditions
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Cognitive Function

Intervention / Treatment
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* Other: Exposure is maternal iodine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Offspring of women recruited to the Southampton Women's Survey Aged 6-7 years at time of measurement Exclusion Criteria: Mother had not provided urine sample before conception of the child

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 7 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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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Exposure is maternal iodine|The exposure is preconception maternal iodine status There is no intervention in this observational study|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cognitive function | Cognitive function assessed using the 2-subtest form of the Wechsler Abbreviated Scale of Intelligence and specific components of executive function (Delayed Matching to Subject (DMS), Spatial Span (SSP) and Intra-Extra Dimensional Set Shift (IED)) from the Cambridge Neuropsychological Test Automated Battery (CANTAB®, Cambridge Cognition, Cambridge, UK) | Age 6-7 years |