title: Excessive iodine intake and thyroid dysfunction among lactating Saharawi women.
abstract: OBJECTIVE
  Excessive iodine intake may lead to thyroid dysfunction, which may be particularly harmful during pregnancy and lactation. The main objective was to describe iodine status and the prevalence of thyroid dysfunction among lactating women in areas with high iodine (HI) and very high iodine (VHI) concentrations in drinking water.
  
  
  METHODS
  A cross-sectional survey was performed among 111 lactating women in the Saharawi refugee camps, Algeria. Breast milk iodine concentration (BMIC), urinary iodine concentration (UIC) and the iodine concentration in the most commonly consumed foods/drinks were measured. A 24-h dietary recall was used to estimate iodine intake. Thyroid hormones and antibodies were measured in serum.
  
  
  RESULTS
  Median UIC, BMIC and iodine intake across both areas was 350 μg/L, 479 μg/L and 407 μg/day, respectively. In multiple regression analyses, we discovered that being from VHI area was associated with higher UIC and BMIC. BMIC was also positively associated with iodine intake. Thyroid dysfunction and/or positive thyroid antibodies were found in 33.3% of the women, of which 18.9% had hypothyroidism and 8.1% had hyperthyroidism and 6.3% had positive antibodies with normal thyroid function. Elevated thyroid antibodies were in total found in 17.1%. We found no difference in distribution of thyroid dysfunction or positive antibodies between HI and VHI areas. BMI, BMIC and elevated thyroglobulin (Tg) predicted abnormal thyroid function tests.
  
  
  CONCLUSIONS
  The high prevalence of thyroid dysfunction may be caused by excessive iodine intake over several years.
authors.affiliation: Department of Health Nutrition and Management, Faculty of Health Sciences, Oslo and Akershus University College, Oslo, Norway; Department of Global Public Health and Primary Care, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway. Electronic address: inger.aakre@hioa.no.
authors.forename: Inger
authors.initials: I
authors.lastname: Aakre
authors.affiliation: Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Trine
authors.initials: T
authors.lastname: Bjøro
authors.affiliation: Department of Endocrinology, Morbid Obesity and Preventive Medicine, Oslo University Hospital, Oslo, Norway.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Norheim
authors.affiliation: Department of Global Public Health and Primary Care, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway; Medical Microbiology, Department of Laboratory Medicine, Medical Services Division, Innlandet Hospital Trust, Lillehammer, Norway.
authors.forename: Tor A
authors.initials: TA
authors.lastname: Strand
authors.affiliation: Department of Health Nutrition and Management, Faculty of Health Sciences, Oslo and Akershus University College, Oslo, Norway.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Barikmo
authors.affiliation: Department of Health Nutrition and Management, Faculty of Health Sciences, Oslo and Akershus University College, Oslo, Norway.
authors.forename: Sigrun
authors.initials: S
authors.lastname: Henjum
mesh_terms: D000328:Adult; D000462:Algeria / Q000453:epidemiology; D001942:Breast Feeding; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000139:chemically induced / Q000453:epidemiology; D007455:Iodine / Q000008:administration & dosage* / Q000097:blood / Q000652:urine; D008895:Milk, Human / Q000737:chemistry*; D013959:Thyroid Diseases / Q000139:chemically induced / Q000453:epidemiology*; D013960:Thyroid Function Tests
chemical_list: D007455:Iodine
keywords: Breast milk iodine; Iodine excess; Lactating women; Thyroid dysfunction; Urinary iodine