Prenatal iodine nutrition and child attention deficit-hyperactivity disorder

Maternal iodine intake and offspring attention deficit-hyperactivity disorder

Status

Active, not recruiting

Phases

Unknown

Study type

Observational

Source

ISRCTN

Registry ID

ISRCTN41848933

Enrollment

77164

Registered

2017-09-14

Start date

2002-03-01

Completion date

Unknown

Last updated

2022-09-05

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Child ADHD diagnosis and maternally reported child ADHD symptoms at age 8 years Mental and Behavioural Disorders

Interventions

1. Maternal iodine intake from food in non-users of supplemental iodine assessed by a food frequency questionnaire in gestational week 22 2. Maternal use of iodine-containing supplemen

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: 1. Pregnant women in their first trimester recruited from all over Norway during the years 1999 to 2008 and asked to answer questionnaires (in Norwegian) at regular intervals during pregnancy and after birth 2. To be included in the current study mothers had to have responded to a general questionnaire around gestational week (GW) 17, and a food frequency questionnaire (FFQ) around GW 22 3. Only singleton pregnancies 4. Only participants with information on all covariates were included in the analysis because of the large sample size and low rates of missing values 5. Pregnant women at any age were allowed to participate

Exclusion criteria

Exclusion criteria: 1. Multiple pregnancies 2. Maternal use of thyroid medication in pregnancy 3. Missing information on important covariates 4. Children registered as dead or emigrated by Jan 2016 5. FFQs with more than 3 blank pages 6. Calculated energy intakes 20 MJ

Design outcomes

Primary

Measure	Time frame
1. Registered child ADHD diagnosis in the Norwegian Patient Registry (NPR) by Dec. 2015. From 2008, all government-owned and government-financed hospitals and outpatient clinics mandatorily report individual level diagnoses defined in the tenth revision of the International Classification of Disease (ICD-10) to the NPR in order to receive financial reimbursement. Using individual personal identification numbers, diagnostic information from NPR was linked to MoBa. Thus all MoBa children registered with an ICD-10-diagnosis of hyperkinetic disorder (HKD coded as F90.0, F90.1, F90.8, or F90.9) between 2008 and 2015 were identified and regarded as having ADHD 2. Child ADHD symptoms assessed in the 8 year questionnaire from MoBa on a 4-point Likert scale (never/rarely, sometimes, often, or very often) covering inattention problems (9 items) and hyperactivity/impulsivity (9 items) from the ADHD Rating Scale	—

Measure

Time frame

1. Registered child ADHD diagnosis in the Norwegian Patient Registry (NPR) by Dec. 2015. From 2008, all government-owned and government-financed hospitals and outpatient clinics mandatorily report individual level diagnoses defined in the tenth revision of the International Classification of Disease (ICD-10) to the NPR in order to receive financial reimbursement. Using individual personal identification numbers, diagnostic information from NPR was linked to MoBa. Thus all MoBa children registered with an ICD-10-diagnosis of hyperkinetic disorder (HKD coded as F90.0, F90.1, F90.8, or F90.9) between 2008 and 2015 were identified and regarded as having ADHD 2. Child ADHD symptoms assessed in the 8 year questionnaire from MoBa on a 4-point Likert scale (never/rarely, sometimes, often, or very often) covering inattention problems (9 items) and hyperactivity/impulsivity (9 items) from the ADHD Rating Scale

—

Secondary

Measure	Time frame
No secondary outcome measures	—

Countries

Norway

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Feb 4, 2026