Effect of Excess Iodine Intake from Iodized Salt and/or Groundwater Iodine on Thyroid Function in Nonpregnant and Pregnant Women, Infants, and Children: A Multicenter Study in East Africa
| Autor: | Michael B. Zimmermann, Fatma Abdallah, Anselimo Makokha, Wanjiku N. Gichohi-Wainaina, Izzeldin Hussein, Vincent Assey, Maria Andersson, Juliawati Untoro, Kalil Sagno, Jessica Farebrother, Ralph Fingerhut, Michael J. Watts |
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| Rok vydání: | 2018 |
| Předmět: |
Adult
Adolescent Excess iodine Endocrinology Diabetes and Metabolism medicine.medical_treatment Thyroid Gland Physiology chemistry.chemical_element 030209 endocrinology & metabolism Iodine 03 medical and health sciences Young Adult 0302 clinical medicine Endocrinology Pregnancy medicine East africa Humans 030212 general & internal medicine Sodium Chloride Dietary Child Groundwater business.industry Thyroid Infant Newborn food and beverages Infant Africa Eastern Diet Iodised salt medicine.anatomical_structure Cross-Sectional Studies Multicenter study chemistry Thyroglobulin Female Thyroid function business |
| Zdroj: | Thyroid : official journal of the American Thyroid Association. 28(9) |
| ISSN: | 1557-9077 |
| Popis: | Acute excess iodine intake can damage the thyroid, but the effects of chronic excess iodine intake are uncertain. Few data exist for pregnant and lactating women and infants exposed to excessive iodine intake.This was a multicenter cross-sectional study. At study sites in rural Kenya and urban Tanzania previously reporting iodine excess in children, urinary iodine concentration (UIC), thyrotropin, total thyroxine, and thyroglobulin (Tg) were measured in school-age children (SAC), women of reproductive age, pregnant (PW) and lactating women, and breast-feeding and weaning infants. In a national study in Djibouti, UIC was measured in SAC and PW. At all sites, daily iodine intake was estimated based on UIC, and iodine concentration was measured in household salt and drinking water.The total sample size was 4636: 1390, 2048, and 1198 subjects from Kenya, Tanzania, and Djibouti, respectively. In Kenya and Tanzania: (i) median UIC was well above thresholds for adequate iodine nutrition in all groups and exceeded the threshold for excess iodine intake in SAC; (ii) iodine concentrations40 mg of iodine/kg were found in approximately 55% of household salt samples; (iii) iodine concentrations ≥10 μg/L were detected in 9% of drinking water samples; (iv) Tg was elevated in all population groups, but the prevalence of thyroid disorders was negligible, except that 5-12% of women of reproductive age had subclinical hyperthyroidism and 10-15% of PW were hypothyroxinemic. In Djibouti: (i) the median UIC was 335 μg/L (interquartile range [IQR] = 216-493 μg/L) in SAC and 265 μg/L (IQR = 168-449 μg/L) in PW; (ii) only 1.6% of Djibouti salt samples (n = 1200) were adequately iodized (15 mg/kg); (iii) the median iodine concentration in drinking water was 92 μg/L (IQR = 37-158 μg/L; n = 77). In all countries, UIC was not significantly correlated with salt or water iodine concentrations.Although iodine intake was excessive and Tg concentrations were elevated, there was little impact on thyroid function. Chronic excess iodine intake thus appears to be well tolerated by women, infants, and children. However, such high iodine intake is unnecessary and should be avoided. Careful evaluation of contributions from both iodized salt and groundwater iodine is recommended before any review of iodization policy is considered. |
| Databáze: | OpenAIRE |
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