Ane Miren Castilla1, Mario Murcia2,3, Juan José Arrizabalaga4, Mercedes Espada1, Jordi Julvez5,6, Mikel Basterrechea5,7,8, Mar Alvarez-Pedrerol5,6,9, Marisa Estarlich5,10, Elena Moreno11, Mònica Guxens5,6,9, Jesús Vioque5,12, Marisa Rebagliato5,10,13. 1. Public Health Laboratory, Basque Government, Bilbao, Spain. 2. Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid, Spain. murcia_mar@gva.es. 3. Epidemiology and Environmental Health Joint Research Unit, FISABIO-Universitat Jaume I-Universitat de València, Av. Catalunya 21, 46020, Valencia, Spain. murcia_mar@gva.es. 4. Endocrinology and Nutrition Service, University Hospital of Álava, Basque Health Service, Vitoria Gasteiz, Spain. 5. Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Madrid, Spain. 6. ISGlobal, Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain. 7. Department of Epidemiology, Public Health Division of Gipuzkoa, Basque Government, Gipuzkoa, Spain. 8. Health Research Institute, Biodonostia, San Sebastian, Spain. 9. Universitat Pompeu Fabra (UFP), Barcelona, Spain. 10. Epidemiology and Environmental Health Joint Research Unit, FISABIO-Universitat Jaume I-Universitat de València, Av. Catalunya 21, 46020, Valencia, Spain. 11. Health Centre of Beasain, Basque Health Service, Beasain, Gipuzkoa, Spain. 12. Department of Public Health, History of Medicine and Gynecology, Universidad Miguel Hernández, San Juan de Alicante, Spain. 13. Department of Medicine, University Jaume I, Castelló de la Plana, Spain.
Abstract
PURPOSE: Median urinary iodine concentration (UIC) is used to describe the iodine status of a population. However, the link between UIC and iodine intake may vary during pregnancy. The aim of this study was to compare UIC during and after pregnancy, adjusting for factors that affect iodine intake. METHODS: Two repeated measures of UIC and data on maternal iodine intake estimated through questionnaires were collected during pregnancy and 1-4 years after pregnancy in a subsample of women (n = 598) from a mother and child cohort study in Spain. Random-effects interval regression was used to assess the changes in UIC according to pregnancy status. RESULTS: Median UIC was similar during (133 μg/L) and after pregnancy (139 μg/L). After adjusting for iodised salt, iodine supplement consumption, and socio-demographic related variables, UIC was 24.0% (95% CI 11.3, 38.2) higher after than during pregnancy. This difference was maintained in a subsample of women with exhaustive information on diet (n = 291): 26.2%, 95% CI 10.3, 44.4. CONCLUSIONS: In an iodine sufficient area for the general population, iodine excretion was lower during than after pregnancy when factors affecting iodine intake were controlled for. Current recommendations of median UIC during pregnancy are based on the equivalence between iodine intake and UIC estimated from studies in non-pregnant populations, which might lead to overestimation of iodine deficiency during gestation. Further studies should evaluate the equivalence between iodine intake and its urinary excretion during pregnancy.
PURPOSE: Median urinary iodine concentration (UIC) is used to describe the iodine status of a population. However, the link between UIC and iodine intake may vary during pregnancy. The aim of this study was to compare UIC during and after pregnancy, adjusting for factors that affect iodine intake. METHODS: Two repeated measures of UIC and data on maternal iodine intake estimated through questionnaires were collected during pregnancy and 1-4 years after pregnancy in a subsample of women (n = 598) from a mother and child cohort study in Spain. Random-effects interval regression was used to assess the changes in UIC according to pregnancy status. RESULTS: Median UIC was similar during (133 μg/L) and after pregnancy (139 μg/L). After adjusting for iodised salt, iodine supplement consumption, and socio-demographic related variables, UIC was 24.0% (95% CI 11.3, 38.2) higher after than during pregnancy. This difference was maintained in a subsample of women with exhaustive information on diet (n = 291): 26.2%, 95% CI 10.3, 44.4. CONCLUSIONS: In an iodine sufficient area for the general population, iodine excretion was lower during than after pregnancy when factors affecting iodine intake were controlled for. Current recommendations of median UIC during pregnancy are based on the equivalence between iodine intake and UIC estimated from studies in non-pregnant populations, which might lead to overestimation of iodine deficiency during gestation. Further studies should evaluate the equivalence between iodine intake and its urinary excretion during pregnancy.
Authors: Esther M Wong; Kevin M Sullivan; Cria G Perrine; Lisa M Rogers; Juan Pablo Peña-Rosas Journal: Food Nutr Bull Date: 2011-09 Impact factor: 2.069
Authors: M Murcia; M Rebagliato; M Espada; J Vioque; L Santa Marina; M Alvarez-Pedrerol; M-J Lopez-Espinosa; G León; C Iñiguez; M Basterrechea; M Guxens; A Lertxundi; A Perales; F Ballester; J Sunyer Journal: J Epidemiol Community Health Date: 2009-12-11 Impact factor: 3.710
Authors: W C Willett; L Sampson; M J Stampfer; B Rosner; C Bain; J Witschi; C H Hennekens; F E Speizer Journal: Am J Epidemiol Date: 1985-07 Impact factor: 4.897