Study of the Effect of Iodized Oil Supplementation During Infancy
Condition: Iodine Deficiency
Study type: Interventional

Summary: 
      In iodine-deficient countries or regions that have inadequate iodized salt distribution, the
      World Health Organization (WHO) recommends choosing one of two methods to improve iodine
      intakes in breastfeeding infants: 1) iodine supplement (400 mg as iodized oil; 1/year) to the
      breastfeeding mother, or 2) iodine supplement (100 mg as iodized oil; 1/year) directly to the
      infant. However, the relative efficacy of these two methods of providing iodine to the
      newborn has never been directly compared. Whether the first method of iodine supplementation
      to the breast feeding mother can significantly improve iodine supply and maintain normal
      thyroid function in her infant remains unclear. This study will directly compare these two
      strategies. The hypothesis is that the two strategies will be equally effective in providing
      iodine to the newborn.
    

Detailed description: 
      In iodine-deficient countries or regions that have inadequate iodized salt distribution, WHO
      recommends choosing one of two methods to improve iodine intakes in breastfeeding infants:

      Method 1) iodine supplement (400 mg as iodized oil; 1/year) to the breastfeeding mother
      Method 2) iodine supplement (100 mg as iodized oil; 1/year) directly to the infant

      However, the relative efficacy of these two methods of providing iodine to the newborn has
      never been directly compared. Whether the first method of iodine supplementation to the
      breast feeding mother can significantly improve iodine supply and maintain normal thyroid
      function in her infant remains unclear.

      The mountains of southern Morocco are areas of iodine deficiency. Although the government has
      been promoting iodization of salt, there are hundreds of small salt producers in the
      mountains who do not have the funding or infrastructure to iodize their salt, and thus many
      rural populations still are consuming non-iodized locally-produced salt. At the study site, a
      2009 pilot survey of urinary iodine has found that the population in this region is
      moderately iodine sufficient.

      Thus, according to WHO, breastfeeding women and/or their infants should be provided with oral
      iodine supplementation. But which of the above supplementation methods is preferable?
      Controlled studies clearly demonstrate that iodine repletion in moderate-to severely iodine
      deficient school-age children increases insulin-like growth factor (IGF)-1 and insulin-like
      growth factor binding protein (IGFBP)-3 concentrations and improves somatic growth (height
      and weight). But whether supplying adequate iodine to iodine deficient infants improves their
      somatic growth has not been tested.

      Therefore, the study hypotheses are: In Moroccan infants who are breastfeeding, method 2 will
      be more efficacious than method 1 in:

        1. increasing urinary iodine (UI) concentrations

        2. improving thyroid function (TSH, TT4)

        3. increasing IGF-1, IGFBP-3

        4. improving somatic growth (length, weight, head circumference)

      The study design will be a double-blind, randomized controlled intervention trial in southern
      Morocco lasting 1 year. Healthy mother-infant pairs (n=240) who are breastfeeding will be
      recruited while the infant is >1 mo of age. They will be divided into two groups as follows:

      1) method 1: mother receives 400 mg of iodine as oral iodized oil + infant receives placebo
      capsule; or 2) method 2: mother receives placebo capsule + infant receives 100 mg oral
      iodized oil.

      The outcomes will be:

        1. length, weight, head circumference

        2. IGF-1, IGFBP-3, thyroid functions (TSH, total T4) from a dried blood spot taken from a
           finger prick in the mothers/heel prick in the infants

        3. urinary and breast milk iodine concentrations These samples (blood spot, urine,
           breastmilk, anthropometry) will be collected during the first year visits of the infant
           to the local health clinic for routine pediatric vaccinations (at 1, 12, 20 and 40-52
           wks).
    

Intervention name(s): Iodized oil
Intervention type(s): Dietary Supplement
Intervention description(s): 400 mg of iodine vs 100 mg of iodine as iodized oil
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: iodine; infant; breastfeeding; deficiency