title: Iodine prophylaxis using iodized salt and risk of maternal thyroid failure in conditions of mild iodine deficiency.
abstract: BACKGROUND
  Mild to moderate iodine deficiency during pregnancy can cause transient maternal hypothyroidism and impaired mental development of the progeny. These unfavorable effects are preventable by iodine supplementation. In Europe, however, less than 50% pregnant women receive iodine-containing supplements, thus representing dietary iodized salt the only carrier of iodine for most women in this life stage.
  
  
  OBJECTIVE
  This longitudinal study is aimed to investigate the effects of long-term iodized salt consumption on maternal thyroid function during gestation. PARTICIPANTS/OUTCOME MEASURES: We prospectively evaluated thyroid function in 100 consecutive thyroperoxidase antibody-negative pregnant women from a mildly iodine-deficient area. Sixty-two women who had regularly used iodized salt for at least 2 yr prior to becoming pregnant and 38 who commenced iodized salt consumption upon becoming pregnant were classified as long-term (LT) and short-term (ST) iodine supplemented, respectively.
  
  
  RESULTS
  Long-term iodized salt consumption resulted in a very low prevalence of maternal thyroid failure (MTF) in LT women. Conversely, short-term iodine prophylaxis does not seem to protect against the risk of MTF, the prevalence of which was almost 6-fold higher in ST than LT women (36.8% vs. 6.4%; chi(2) 14.7, P < 0.0005; relative risk 5.7, 95% confidence interval 2.03-16.08, P < 0.001). The relative risk reduction amounted to 82.5%, this measure indicating the extent to which long-term iodine prophylaxis using iodized salt would reduce the risk of MTF in ST women.
  
  
  CONCLUSIONS
  Prolonged iodized salt significantly improves maternal thyroid economy and reduces the risk of maternal thyroid insufficiency during gestation, probably because of a nearly restoring intrathyroidal iodine stores.
authors.affiliation: Cattedra di Endocrinologia, Policlinico Universitario, Via Consolare Valeria, 98125 Messina, Italy.
authors.forename: Mariacarla
authors.initials: M
authors.lastname: Moleti
authors.forename: Vincenzo Pio
authors.initials: VP
authors.lastname: Lo Presti
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Campolo
authors.forename: Filiberto
authors.initials: F
authors.lastname: Mattina
authors.forename: Marina
authors.initials: M
authors.lastname: Galletti
authors.forename: Mattia
authors.initials: M
authors.lastname: Mandolfino
authors.forename: Maria Antonia
authors.initials: MA
authors.lastname: Violi
authors.forename: Grazia
authors.initials: G
authors.lastname: Giorgianni
authors.forename: Demetrio
authors.initials: D
authors.lastname: De Domenico
authors.forename: Francesco
authors.initials: F
authors.lastname: Trimarchi
authors.forename: Francesco
authors.initials: F
authors.lastname: Vermiglio
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000209:etiology / Q000517:prevention & control*; D007455:Iodine / Q000008:administration & dosage / Q000172:deficiency*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000209:etiology / Q000517:prevention & control*; D011446:Prospective Studies; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage*; D013954:Thyroglobulin / Q000097:blood; D013974:Thyroxine / Q000097:blood
chemical_list: D017673:Sodium Chloride, Dietary; C034024:iodized salt; D013954:Thyroglobulin; D007455:Iodine; D013974:Thyroxine