Tammaro A, Pigliacelli F, Fumarola A, Persechino S
UOC Dermatology, NESMOS Department, University of Rome Sapienza, Rome, Italy. Via di Grottarossa, 1035, Roma, Italy Phone: +39 06 3377 5979 Fax: +39 06 3377 5378 E-mail:
UOC Dermatology, NESMOS Department, University of Rome Sapienza, Rome, Italy.
Eur Ann Allergy Clin Immunol. 2016 May;48(3):77-81.
Background. Mandatory iodine fortification of salt was introduced in Italy in 2005. The purpose of our study is to estimate the trend of thyroid diseases in Italy before and after mandatory iodization in Italy. Methods. 7976 patients (6802 females; 1174 males) were examined between 2003 and 2010. We divided the patients into categories according to their clinical diagnosis. Later, we evaluated for each patient if there was the positivity for antibodies anti TPO. Finally, we collected data about TSH values of all patients who did not use therapy for thyroid disease at the time of the examination. To evaluate the differences percentages for categorical variables, χ2-Pearson test was used; to evaluate the percentage differences of TSH values we used the Kruskal-Wallis test. Values were considered statistically significant at p < 0.05. Results. We considered diagnosis of "toxic adenoma / goiter", diagnosis of "Graves' disease" and diagnosis of "hyperthyroidism / thyrotoxicosis" before and after the introduction of mandatory iodization in Italy, to demonstrate the possible presence of iodine-induced hyperthyroidism. Diagnosis of toxic adenoma / goiter before 2005 were 3.7%, while after 2005 they were reduced to 3.1%. Diagnosis of Graves' disease before 2005 were 2.4%, and they remained unchanged after 2005. Finally, diagnosis of hyperthyroidism / thyrotoxicosis decreased from 2.5% to 2.1%. Comparing these results, there were no significant differences (P = 0.261) between the percentages of diagnosis of hyperthyroidism before and after the introduction of mandatory iodization. We considered diagnosis of Hashimoto's thyroiditis before and after 2005 to demonstrate a link between the administration of iodine and thyroid autoimmunity. Prevalence of Hashimoto's thyroiditis between 2003 and 2005 was 37%; prevalence between 2006 and 2010 dropped to 34.7%. This small difference has a borderline statistical significance (P = 0.049). Stratifying TSH values from year to year, we found a small increase in TSH value, which, in any case, remains in the normal range. TSH values passed from 1.37 in 2003, to 1.61 in 2010. Although this increase is modest, it is statistically significant (P values < 0.001). Conclusion. In this study there isn't a connection between iodine fortification and iodine-induced hyperthyroidism, and between iodine fortification and Hashimoto's thyroiditis. This small increase of TSH values can not find a clear explanation yet. We considered several mechanisms to explain this phenomenon: alterations of Na/I symporter reduce intracellular levels of iodine, and cause a state of hypothyroidism; excessive levels of iodine can increase apoptosis of thyrocytes, as it is demonstrated by several studies; interference from external agents (endocrine disruptors).
背景。意大利于2005年开始强制实施食盐加碘。我们研究的目的是评估意大利强制加碘前后甲状腺疾病的发展趋势。方法。在2003年至2010年期间对7976例患者（6802例女性；1174例男性）进行了检查。我们根据患者的临床诊断将其分类。随后，我们评估每位患者抗甲状腺过氧化物酶抗体是否呈阳性。最后，我们收集了所有在检查时未接受甲状腺疾病治疗的患者的促甲状腺激素（TSH）值数据。为评估分类变量的差异百分比，使用了χ² - 皮尔逊检验；为评估TSH值的百分比差异，我们使用了克鲁斯卡尔 - 沃利斯检验。当p < 0.05时，数值被认为具有统计学意义。结果。我们考虑了意大利强制加碘前后“毒性腺瘤/甲状腺肿”、“格雷夫斯病”以及“甲状腺功能亢进/甲状腺毒症”的诊断情况，以证明碘致甲状腺功能亢进可能存在。2005年前毒性腺瘤/甲状腺肿的诊断率为3.7%，而2005年后降至3.1%。2005年前格雷夫斯病的诊断率为2.4%，2005年后保持不变。最后，甲状腺功能亢进/甲状腺毒症的诊断率从2.5%降至2.1%。比较这些结果，强制加碘前后甲状腺功能亢进诊断率的百分比之间无显著差异（P = 0.261）。我们考虑了2005年前后桥本甲状腺炎的诊断情况，以证明碘的摄入与甲状腺自身免疫之间的联系。2003年至2005年期间桥本甲状腺炎的患病率为37%；2006年至2010年期间降至34.7%。这一微小差异具有临界统计学意义（P = 0.049）。逐年分层分析TSH值，我们发现TSH值有小幅升高，无论如何仍处于正常范围内。TSH值从2003年的1.37升至2010年的1.61。尽管这一升高幅度不大，但具有统计学意义（P值< 0.001）。结论。在本研究中，食盐加碘与碘致甲状腺功能亢进以及食盐加碘与桥本甲状腺炎之间没有关联。TSH值的这一小幅升高目前尚无明确解释。我们考虑了几种机制来解释这一现象：钠/碘同向转运体的改变会降低细胞内碘水平，并导致甲状腺功能减退状态；多项研究表明，过量的碘会增加甲状腺细胞的凋亡；外部因素（内分泌干扰物）的干扰。
