Anne Krejbjerg1, Lena Bjergved, Inge Bülow Pedersen, Nils Knudsen, Torben Jørgensen, Hans Perrild, Lars Ovesen, Lone Banke Rasmussen, Peter Laurberg. 1. Departments of Clinical Medicine and Endocrinology (A.K., I.B.P., P.L.), Aalborg University and Aalborg University Hospital, and Faculty of Medicine (T.J.), Aalborg University, DK-9000 Aalborg, Denmark; Research Centre for Prevention and Health (L.B., T.J.), The Capital Region of Denmark, DK-2600 Glostrup, Denmark; Department of Endocrinology (L.B., N.K., H.P.), Bispebjerg University Hospital, DK-2400 Copenhagen, Denmark; Faculty of Health Sciences (T.J.), DK-2200 Copenhagen, Denmark; Department of Gastroenterology (L.O.), Slagelse Hospital, DK-4200 Slagelse, Denmark; and Department of Nutrition (L.B.R.), National Food Institute, Technical University of Denmark, DK-2860 Søborg, Denmark.
Abstract
CONTEXT: Limited longitudinal data are available on changes in the thyroid gland structure in a population and how this is influenced by iodine fortification (IF). OBJECTIVE: Our objective was to clarify how IF influenced thyroid gland structure in 2 regions with different iodine intake at baseline (Copenhagen, mild iodine deficiency [ID]; Aalborg, moderate ID). DESIGN AND SETTING: We conducted a longitudinal population-based study (DanThyr) where participants were examined before (1997) and after (2008) the Danish mandatory IF of salt (2000). PARTICIPANTS: We examined 2465 adults, and ultrasonography was performed by the same sonographers using the same equipment, after controlling performances. MAIN OUTCOME MEASURE: Change in thyroid gland structure was evaluated. RESULTS: The follow-up period saw an increased prevalence of multinodularity (9.8%-13.8 %, P < .001), especially in the previously moderate ID region of Aalborg (9.1%-15.4%, P < .001), whereas no change in prevalence was seen for solitary nodules (5.6%-5.1%, P = .34). In individual participants, changes in thyroid structure and disappearance of thyroid nodules during the 11 years was common with an overall normalization rate of 21.2 (95% confidence interval [CI] = 17.9-24.9) per 1000 person-years. Solitary nodules had a significantly higher normalization rate than multiple nodules (normalization rate ratio 0.47 [95% CI = 0.32-0.67]). A regional difference (Aalborg vs Copenhagen) was seen between normalization rates of multiple nodules (normalization rate ratio 0.29 [95% CI = 0.12-0.64]), but not for solitary nodules (normalization rate ratio 0.81 [95% CI = 0.53-1.21]). CONCLUSIONS: Changes in the thyroid gland structure with both appearance and disappearance of thyroid nodules are common after an iodization program.
CONTEXT: Limited longitudinal data are available on changes in the thyroid gland structure in a population and how this is influenced by iodine fortification (IF). OBJECTIVE: Our objective was to clarify how IF influenced thyroid gland structure in 2 regions with different iodine intake at baseline (Copenhagen, mild iodine deficiency [ID]; Aalborg, moderate ID). DESIGN AND SETTING: We conducted a longitudinal population-based study (DanThyr) where participants were examined before (1997) and after (2008) the Danish mandatory IF of salt (2000). PARTICIPANTS: We examined 2465 adults, and ultrasonography was performed by the same sonographers using the same equipment, after controlling performances. MAIN OUTCOME MEASURE: Change in thyroid gland structure was evaluated. RESULTS: The follow-up period saw an increased prevalence of multinodularity (9.8%-13.8 %, P < .001), especially in the previously moderate ID region of Aalborg (9.1%-15.4%, P < .001), whereas no change in prevalence was seen for solitary nodules (5.6%-5.1%, P = .34). In individual participants, changes in thyroid structure and disappearance of thyroid nodules during the 11 years was common with an overall normalization rate of 21.2 (95% confidence interval [CI] = 17.9-24.9) per 1000 person-years. Solitary nodules had a significantly higher normalization rate than multiple nodules (normalization rate ratio 0.47 [95% CI = 0.32-0.67]). A regional difference (Aalborg vs Copenhagen) was seen between normalization rates of multiple nodules (normalization rate ratio 0.29 [95% CI = 0.12-0.64]), but not for solitary nodules (normalization rate ratio 0.81 [95% CI = 0.53-1.21]). CONCLUSIONS: Changes in the thyroid gland structure with both appearance and disappearance of thyroid nodules are common after an iodization program.
Authors: Juraci A Cesar; Iná S Santos; Robert E Black; Maria A D Chrestani; Fabio A Duarte; Eduardo A F Nilson Journal: Nutrients Date: 2020-04-13 Impact factor: 5.717