The impact of the micronutrient iodine in health and diseases.

Adequate iodine nutrition is crucial for all mammals by playing his starring role as a component of thyroid hormones, which are key regulators of cellular processes for life such as differentiation, growth, function, and metabolism. Deficiency or excess of iodine in the diet are worldwide highly frequent conditions that are responsible of health problems like hypothyroidism, hypothyroxinemia, goiter, thyroiditis, hyperthyroidism, and autoimmune thyroid diseases among others. The incorporation of iodine in salt or other nutrients resolved the consequences of severe iodine deficiency like goiter, cretinism. However, this strategy in several countries led to other ailments like Hashimoto autoimmune thyroiditis, hyperthyroidism, and hypothyroidism. The goal of this review is to analyze and discuss the different aspects of iodine nutrition for human health comprising its biological role through thyroid hormones, pathogen control, and the regulation of the intestinal microbiota.

Cholestasis secondary to hyperthyroidism in Graves' disease. Report of one case.

Hyperthyroidism can induce elevation in several liver function tests including aminotransferases, alkaline phosphatases and, less frequently, serum bilirubin. These alterations are usually mild and asymptomatic. We report a 26 year-old male presenting with palpitations, progressive jaundice, choluria and generalized itching. Laboratory tests were compatible with hyperthyroidism and a mild elevation of bilirubin, alkaline phosphatases and gamma glutamyl transpeptidase. A liver biopsy showed portal hepatitis with canalicular cholestasis. The patient was treated temporarily with glucocorticoids, cholestyramine and betablockade. Thereafter, he was treated with radioactive iodine, after which serum bilirubin decreased steadily until normalization in ten weeks.

Association of Thyroid Function Test Abnormalities and Thyroid Autoimmunity With Preterm Birth: A Systematic Review and Meta-analysis.

Importance: Maternal hypothyroidism and hyperthyroidism are risk factors for preterm birth. Milder thyroid function test abnormalities and thyroid autoimmunity are more prevalent, but it remains controversial if these are associated with preterm birth. Objective: To study if maternal thyroid function test abnormalities and thyroid autoimmunity are risk factors for preterm birth. Data Sources and Study Selection: Studies were identified through a search of the Ovid MEDLINE, EMBASE, Web of Science, the Cochrane Central Register of Controlled Trials, and Google Scholar databases from inception to March 18, 2018, and by publishing open invitations in relevant journals. Data sets from published and unpublished prospective cohort studies with data on thyroid function tests (thyrotropin [often referred to as thyroid-stimulating hormone or TSH] and free thyroxine [FT4] concentrations) or thyroid peroxidase (TPO) antibody measurements and gestational age at birth were screened for eligibility by 2 independent reviewers. Studies in which participants received treatment based on abnormal thyroid function tests were excluded. Data Extraction and Synthesis: The primary authors provided individual participant data that were analyzed using mixed-effects models. Main Outcomes and Measures: The primary outcome was preterm birth (<37 weeks' gestational age). Results: From 2526 published reports, 35 cohorts were invited to participate. After the addition of 5 unpublished data sets, a total of 19 cohorts were included. The study population included 47 045 pregnant women (mean age, 29 years; median gestational age at blood sampling, 12.9 weeks), of whom 1234 (3.1%) had subclinical hypothyroidism (increased thyrotropin concentration with normal FT4 concentration), 904 (2.2%) had isolated hypothyroxinemia (decreased FT4 concentration with normal thyrotropin concentration), and 3043 (7.5%) were TPO antibody positive; 2357 (5.0%) had a preterm birth. The risk of preterm birth was higher for women with subclinical hypothyroidism than euthyroid women (6.1% vs 5.0%, respectively; absolute risk difference, 1.4% [95% CI, 0%-3.2%]; odds ratio [OR], 1.29 [95% CI, 1.01-1.64]). Among women with isolated hypothyroxinemia, the risk of preterm birth was 7.1% vs 5.0% in euthyroid women (absolute risk difference, 2.3% [95% CI, 0.6%-4.5%]; OR, 1.46 [95% CI, 1.12-1.90]). In continuous analyses, each 1-SD higher maternal thyrotropin concentration was associated with a higher risk of preterm birth (absolute risk difference, 0.2% [95% CI, 0%-0.4%] per 1 SD; OR, 1.04 [95% CI, 1.00-1.09] per 1 SD). Thyroid peroxidase antibody-positive women had a higher risk of preterm birth vs TPO antibody-negative women (6.6% vs 4.9%, respectively; absolute risk difference, 1.6% [95% CI, 0.7%-2.8%]; OR, 1.33 [95% CI, 1.15-1.56]). Conclusions and Relevance: Among pregnant women without overt thyroid disease, subclinical hypothyroidism, isolated hypothyroxinemia, and TPO antibody positivity were significantly associated with higher risk of preterm birth. These results provide insights toward optimizing clinical decision-making strategies that should consider the potential harms and benefits of screening programs and levothyroxine treatment during pregnancy.

[Risk of recurrence in differentiated thyroid cancer]. / Riesgo de recurrencia en cáncer diferenciado de tiroides: escala MINSAL.

BACKGROUND: Differentiated thyroid cancer (DTC) is generally associated with a favorable prognosis. Its treatment requires surgery, selective use of radioiodine and levothyroxine, and its intensity must be adjusted to the initial risks of mortality and recurrence. AIM: To validate the risk of recurrence classification developed by the Chilean Ministry of Health in 2013 (MINSAL 2013), and compare it with the American Thyroid Association (ATA) 2009 and 2015 classifications. MATERIAL AND METHODS: Retrospective study of 362 patients with DTC aged 44.3 ± 13.4 years (84% women), treated with total thyroidectomy, selective radioiodine ablation and levothyroxine and followed for a median of 4.2 years (range 2.0-7.8). Risk of recurrence was estimated with MINSAL 2013, ATA 2009 and ATA 2015 classifications, and risk of mortality with 7th and 8th American Joint Committee on Cancer (AJCC)/TNM systems. Clinical data obtained during follow-up were used to detect structural and biochemical persistence/recurrence. RESULTS: A mean dose of 104 ± 48 mCi radioiodine was received by 91% of patients. MINSAL 2013 classified 148 (41%), 144 (40%), 67 (19%) and 3 (1%) patients as very low, low, intermediate and high risk of recurrence, respectively. Forty-five (12.4%) patients had persistence or recurrence during follow-up: 33 structural and 12 biochemical. Rates of persistence/recurrence on each category of MINSAL 2013 were 4.1%, 7.6%, 37.3% and 100%, respectively (p < 0.01). Areas under Receiver Operating Characteristic curves for persistence or recurrence of MINSAL 2013, ATA 2009 and ATA 2015 were 0.77 vs 0.73 vs 0.72, respectively. CONCLUSIONS: MINSAL 2013 classifies appropriately DTC patients and estimates correctly their risk of persistence or recurrence.

Early pregnancy thyroid hormone reference ranges in Chilean women: the influence of body mass index.

OBJECTIVE: Thyroid dysfunction and obesity during pregnancy have been associated with negative neonatal and obstetric outcomes. Thyroid hormone reference ranges have not been established for the pregnant Hispanic population. This study defines thyroid hormone reference ranges during early pregnancy in Chilean women and evaluates associations of body mass index (BMI) with thyroid function. DESIGN, PATIENTS, MEASUREMENTS: This is a prospective observational study of 720 healthy Chilean women attending their first prenatal consultation at an outpatient clinic. Thyroid function [TSH, Free T4, Total T4 and antithyroid peroxidase antibodies (TPOAb)] and BMI were assessed at 8·8 ± 2·4 weeks of gestational age. RESULTS: Median, 2·5th percentile (p2·5), and 97·5th percentile (p97·5) TSH values were higher, while median, p2·5, and p97·5 free T4 values were lower in obese patients compared with normal weight patients. Obesity was associated with a median TSH 16% higher (P = 0·035) and a median free T4 6·5% lower (P < 0·01) than values from patients with normal weight. BMI had a small, but statistically significant effect on TSH (P = 0·04) and free T4 (P < 0·01) when adjusted by maternal age, TPO antibodies, parity, sex of the newborn, gestational age and smoking. In all TPOAb (-) patients, median (p2·5-p.97·5) TSH was 1·96 mIU/l (0·11-5·96 mIU/l) and median (p2·5-p.97·5) free T4 was 14·54 pmol/l (11·1 - 19·02 pmol/l). Applying these reference limits, we found a prevalence of overt and subclinical hypothyroidism of 0·9% and 3·05% respectively. CONCLUSIONS: TSH distributes at higher values and free T4 at lower values in obese pregnant women compared to normal weight pregnant women. Thyroid hormone reference ranges derived from Chilean patients with negative TPOAb are different from the fixed internationally proposed reference ranges and may be used in the Hispanic population.

Active surveillance is a feasible and safe strategy in selected patients with papillary thyroid cancer and suspicious cervical lymph nodes detected after thyroidectomy.

Objective: After initial treatment, up to 30% of patients with papillary thyroid cancer (PTC) have incomplete response, mainly cervical lymph node (LN) disease. Previous studies have suggested that active surveillance (AS) is a possible option for these patients. Our aim was to report the results of AS in patients with PTC and cervical LN disease. Materials and methods: In this retrospective observational study, we included adult patients treated and followed for PTC, who presented with cervical LN disease and were managed with AS. Growth was defined as an increase ≥ 3mm in either diameter. Results: We included 32 patients: 27 (84.4%) women, age of 39 ± 14 years, all initially treated with total thyroidectomy, and 22 (69%) with therapeutic neck dissection. Cervical LN disease was diagnosed 1 year (0.3-12.6) after initial management, with a diameter of 9.0 mm (6.0-19.0). After a median AS of 4.3 years (0.6-14.1), 4 (12.5%) patients had LNgrowth: 2 (50%) of whom were surgically removed, 1 (25%) was effectively treated with radiotherapy, and 1 (25%) had a scheduled surgery. Tg increase was the only predictive factor of LN growth evaluated as both the delta Tg (p < 0.0366) and percentage of Tg change (p < 0.0140). None of the included patients died, had local complications due to LN growth or salvage therapy, or developed distant metastases during follow-up. Conclusion: In selected patients with PTC and suspicious cervical LNs diagnosed after initial treatment, AS is a feasible and safe strategy as it allows effective identification and treatment of the minority of patients who progress.

Lobectomy in patients with differentiated thyroid cancer: experience of a Chilean tertiary center.

PURPOSE: Thyroid lobectomy (TL) is an appropriate treatment for up to 4 cm intrathyroidal differentiated thyroid cancer (DTC). There is scarce data regarding TL outside first-world centers. Our aim is to report a cohort of patients with DTC treated with TL in Chile. METHODS: We included DTC patients treated with TL, followed for at least 6 months, characterized their clinicopathological features and classified their risk of recurrence and response to treatment. RESULTS: Eighty-two patients followed for a median of 2.3 years (0.5-7.0). Seventy-three (89%) patients had papillary, 8 (9.8%) follicular and 1 (1.2%) high-grade DTC. The risk of recurrence was low in 56 (68.3%) and intermediate in 26 (31.7%). Eight (9.8%) patients required early completion thyroidectomy and radioiodine. At last follow-up, 52 (70.3%) had excellent, 19 (25.7%) had indeterminate, and 1 (1.4%) had structural incomplete response. CONCLUSION: In a developing country, TL is an adequate option for appropriately selected DTC patients.

Risk Factors for Thyroid Dysfunction in Pregnancy: An Individual Participant Data Meta-Analysis.

Background: International guidelines recommend targeted screening to identify gestational thyroid dysfunction. However, currently used risk factors have questionable discriminative ability. We quantified the risk for thyroid function test abnormalities for a subset of risk factors currently used in international guidelines. Methods: We included prospective cohort studies with data on gestational maternal thyroid function and potential risk factors (maternal age, body mass index [BMI], parity, smoking status, pregnancy through in vitro fertilization, twin pregnancy, gestational age, maternal education, and thyroid peroxidase antibody [TPOAb] or thyroglobulin antibody [TgAb] positivity). Exclusion criteria were pre-existing thyroid disease and use of thyroid interfering medication. We analyzed individual participant data using mixed-effects regression models. Primary outcomes were overt and subclinical hypothyroidism and a treatment indication (defined as overt hypothyroidism, subclinical hypothyroidism with thyrotropin >10 mU/L, or subclinical hypothyroidism with TPOAb positivity). Results: The study population comprised 65,559 participants in 25 cohorts. The screening rate in cohorts using risk factors currently recommended (age >30 years, parity ≥2, BMI ≥40) was 58%, with a detection rate for overt and subclinical hypothyroidism of 59%. The absolute risk for overt or subclinical hypothyroidism varied <2% over the full range of age and BMI and for any parity. Receiver operating characteristic curves, fitted using maternal age, BMI, smoking status, parity, and gestational age at blood sampling as explanatory variables, yielded areas under the curve ranging from 0.58 to 0.63 for the primary outcomes. TPOAbs/TgAbs positivity was associated with overt hypothyroidism (approximate risk for antibody negativity 0.1%, isolated TgAb positivity 2.4%, isolated TPOAb positivity 3.8%, combined antibody positivity 7.0%; p < 0.001), subclinical hypothyroidism (risk for antibody negativity 2.2%, isolated TgAb positivity 8.1%, isolated TPOAb positivity 14.2%, combined antibody positivity 20.0%; p < 0.001) and a treatment indication (risk for antibody negativity 0.2%, isolated TgAb positivity 2.2%, isolated TPOAb positivity 3.0%, and combined antibody positivity 5.1%; p < 0.001). Twin pregnancy was associated with a higher risk of overt hyperthyroidism (5.6% vs. 0.7%; p < 0.001). Conclusions: The risk factors assessed in this study had poor predictive ability for detecting thyroid function test abnormalities, questioning their clinical usability for targeted screening. As expected, TPOAb positivity (used as a benchmark) was a relevant risk factor for (subclinical) hypothyroidism. These results provide insights into different risk factors for gestational thyroid dysfunction.

[Survey on moral judgment criteria among medical students]. / Criterios de juicio moral de estudiantes de Medicina, según el Modelo Intuitivo Social.

BACKGROUND: The evaluation of moral judgment criteria in medical students is important to develop effective educational programs in bioethics. AIM: To compare priority judgment criteria and moral judgment tendency in medical students of first and fifth grade. MATERIAL AND METHODS: The Moral Foundations Questionnaire (MFQ30), to identify moral criteria was applied to 259 students, 63.7% from first year and 50.2% women. RESULTS: The dominant moral tendency both in first and fifth year students was liberal. Justice and compassion were the most important criteria in men and in women, respectively. Respect towards authority and sanctity were the least important criteria in women and men, respectively. CONCLUSIONS: The implications for moral psychology and medical education of these results are discussed.

[Thyroid stimulating hormone reference values derived from the 2009-2010 Chilean National Health Survey]. / Aproximación al patrón de normalidad de TSH para la población chilena según Encuesta Nacional de Salud 2009-2010.

BACKGROUND: The determination of thyroid stimulating hormone (TSH) reference values is critical for the diagnosis of thyroid diseases. AIM: To explore and discuss different definitions to establish TSH reference values using a Chilean national survey sample. MATERIAL AND METHODS: The 2009-2010 Chilean National Health Survey recruited 5,416 participants between the ages of 15 and 96 years, from all geographic regions of Chile, including urban and rural zones. TSH was measured in a random subsample of 2,785 adults. Median value, 2.5 and 97.5 percentiles were described in three different populations: total survey population, "disease-free population" and the "laboratory kit disease free population". RESULTS: TSH values were higher among women, the elderly and the less educated population. The 97.5 percentile value in the disease-free population was 7.46 uUl/ml. Using this value as a cut-off, hypothyroidism prevalence would be 4.8% in Chile and estimated pharmacological treatment coverage would be 58%. When laboratory kit cut-offs are used, prevalence rises to 22% and treatment coverage drops to 12%. The 2.5 percentile value in the disease-free population was 0.83 uUl/ml, which yields an estimated hyperthyroidism prevalence of 3.89%. CONCLUSIONS: Median TSH concentration values in the Chilean "disease-free population" are higher than those proposed by laboratory kits and those of developed countries. TSH values in the general population of Chile are also higher in women, the elderly and the less educated population.

[From macro to micro thyroid carcinoma: records of a clinical hospital from 1991 to 2010]. / Del macro al microcarcinoma tiroideo: cambios en las características de presentación del cáncer de tiroides en un centro universitario chileno en 20 años.

BACKGROUND: The prevalence of thyroid cancer has increased, particularly in nodules smaller than 10 mm, probably due to the growing use of routine thyroid ultrasound. There is controversy about the biological behavior of micro carcinomas and the relevance of their early detection. AIM: To characterize the clinical presentation of thyroid cancer over 20 years in an University medical center and to evaluate the differences between macro and micro carcinomas. PATIENTS AND METHODS: We reviewed 1547 surgical biopsy records of thyroid cancer in our institution obtained between 1991 and 2010. RESULTS: We observed a sustained increase in the rate of thyroidectomies for thyroid cancer (per 1000 surgical procedures) in the study period. Papillary, follicular, mixed, medullary and anaplastic carcinomas were observed in 95, 3, 2, 0.5 and 0.1% of biopsies, respectively. The incidence of tumors of less than 10 mm (micro carcinoma) also increased. Those findings were associated with a significant decrease in tumor aggressiveness, determined by a low frequency of surgical margin involvement of thyroid capsule, perithyroid tissue invasion, vascular permeation and lymph node metastases. CONCLUSIONS: The increased prevalence of thyroid cancer, especially of micro carcinomas, may reflect the greater use of diagnostic ultrasound or represent a real change in the biological behavior of this disease and our data suggest that further studies are needed to know the impact of early treatment in the outcome of those patients because of the real less histologic agressiveness of micro carcinomas.

ThyroidPrint®: clinical utility for indeterminate thyroid cytology.

Molecular testing contributes to improving the diagnosis of indeterminate thyroid nodules (ITNs). ThyroidPrint® is a ten-gene classifier aimed to rule out malignancy in ITN. Post-validation studies are necessary to determine the real-world clinical benefit of ThyroidPrint® in patients with ITN. A single-center, prospective, noninterventional clinical utility study was performed, analyzing the impact of ThyroidPrint® in the physicians' clinical decisions for ITN. Demographics, nodule characteristics, benign call rates (BCRs), and surgical outcomes were measured. Histopathological data were collected from surgical biopsies of resected nodules. Of 1272 fine-needle aspirations, 109 (8.6%) were Bethesda III and 135 (10.6%) were Bethesda IV. Molecular testing was performed in 155 of 244 ITN (63.5%), of which 104 were classified as benign (BCR of 67.1%). After a median follow-up of 15 months, 103 of 104 (99.0%) patients with a benign ThyroidPrint® remained under surveillance and one patient underwent surgery which was a follicular adenoma. Surgery was performed in all 51 patients with a suspicious for malignancy as per ThyroidPrint® result and in 56 patients who did not undergo testing, with a rate of malignancy of 70.6% and 32.1%, respectively. A higher BCR was observed in follicular lesion of undetermined significance (87%) compared to atypia of undetermined significance (58%) (P < 0.05). False-positive cases included four benign follicular nodules and six follicular and four oncocytic adenomas. Our results show that, physicians chose active surveillance instead of diagnostic surgery in all patients with a benign ThyroidPrint® result, reducing the need for diagnostic surgery in 67% of patients with preoperative diagnosis of ITN.

[Frequency of subclinical thyroid problems among women during the first trimester of pregnancy]. / Elevada frecuencia de enfermedad tiroidea funcional en embarazadas chilenas sin antecedentes de patología tiroidea utilizando el estándar de TSH internacional.

BACKGROUND: Thyroid hormones play an important role in fetal neural and cognitive development. Therefore thyroid abnormalities should be detected and treated early during pregnancy. AIM: To assess the frequency and risk factors for functional thyroid disorders during the first trimester of pregnancy. MATERIAL AND METHODS: A blood sample was obtained from women during their first trimester of pregnancy, consulting in a prenatal care facility. Women with known thyroid diseases were excluded from the study. Thyroid stimulating hormone (TSH), total thyroxine (T4) and free thyroxine (fT4) were measured by electrochemoluminiscence. Antithyroid peroxidase antibodies (anti TPO) were measured by enzyme immunoassay. RESULTS: Five hundred and ten women aged 25.7 ± 6.6 years were assessed. The frequency of clinical hypothyroidism was 0.6%, subclinical hypothyroidism 35.3% and clinical hyperthyroidism 1%. Five percent of women with hypothyroidism and 3.5% of euthyroid women had positive anti TPO antibodies. There was no association between the frequency of thyroid diseases and risk factors for thyroid diseases. CONCLUSIONS: There is a high frequency of subclinical thyroid diseases among women consulting in this prenatal care clinic.

Association of Thyroid Peroxidase Antibodies and Thyroglobulin Antibodies with Thyroid Function in Pregnancy: An Individual Participant Data Meta-Analysis.

Objectives: Thyroid autoimmunity is common in pregnant women and associated with thyroid dysfunction and adverse obstetric outcomes. Most studies focus on thyroid peroxidase antibodies (TPOAbs) assessed by a negative-positive dichotomy and rarely take into account thyroglobulin antibodies (TgAbs). This study aimed at determining the association of TPOAbs and TgAbs, respectively, and interdependently, with maternal thyroid function. Methods: This was a meta-analysis of individual participant cross-sectional data from 20 cohorts in the Consortium on Thyroid and Pregnancy. Women with multiple pregnancy, pregnancy by assisted reproductive technology, history of thyroid disease, or use of thyroid interfering medication were excluded. Associations of (log2) TPOAbs and TgAbs (with/without mutual adjustment) with cohort-specific z-scores of (log2) thyrotropin (TSH), free triiodothyronine (fT3), total triiodothyronine (TT3), free thyroxine (fT4), total thyroxine (TT4), or triiodothyronine:thyroxine (T3:T4) ratio were evaluated in a linear mixed model. Results: In total, 51,138 women participated (51,094 had TPOAb-data and 27,874 had TgAb-data). Isolated TPOAb positivity was present in 4.1% [95% confidence interval, CI: 3.0 to 5.2], isolated TgAb positivity in 4.8% [CI: 2.9 to 6.6], and positivity for both antibodies in 4.7% [CI: 3.1 to 6.3]. Compared with antibody-negative women, TSH was higher in women with isolated TPOAb positivity (z-score increment 0.40, CI: 0.16 to 0.64) and TgAb positivity (0.21, CI: 0.10 to 0.32), but highest in those positive for both antibodies (0.54, CI: 0.36 to 0.71). There was a dose-response effect of higher TPOAb and TgAb concentrations with higher TSH (TSH z-score increment for TPOAbs 0.12, CI: 0.09 to 0.15, TgAbs 0.08, CI: 0.02 to 0.15). When adjusting analyses for the other antibody, only the association of TPOAbs remained statistically significant. A higher TPOAb concentration was associated with lower fT4 (p < 0.001) and higher T3:T4 ratio (0.09, CI: 0.03 to 0.14), however, the association with fT4 was not significant when adjusting for TgAbs (p = 0.16). Conclusions: This individual participant data meta-analysis demonstrated an increase in TSH with isolated TPOAb positivity and TgAb positivity, respectively, which was amplified for individuals positive for both antibodies. There was a dose-dependent association of TPOAbs, but not TgAbs, with TSH when adjusting for the other antibody. This supports current practice of using TPOAbs in initial laboratory testing of pregnant women suspected of autoimmune thyroid disease. However, studies on the differences between TPOAb- and TgAb-positive women are needed to fully understand the spectrum of phenotypes.

TSH and FT4 Reference Intervals in Pregnancy: A Systematic Review and Individual Participant Data Meta-Analysis.

CONTEXT: Interpretation of thyroid function tests during pregnancy is limited by the generalizability of reference intervals between cohorts due to inconsistent methodology. OBJECTIVE: (1) To provide an overview of published reference intervals for thyrotropin (TSH) and free thyroxine (FT4) in pregnancy, (2) to assess the consequences of common methodological between-study differences by combining raw data from different cohorts. METHODS: (1) Ovid MEDLINE, EMBASE, and Web of Science were searched until December 12, 2021. Studies were assessed in duplicate. (2) The individual participant data (IPD) meta-analysis was performed in participating cohorts in the Consortium on Thyroid and Pregnancy. RESULTS: (1) Large between-study methodological differences were identified, 11 of 102 included studies were in accordance with current guidelines; (2) 22 cohorts involving 63 198 participants were included in the meta-analysis. Not excluding thyroid peroxidase antibody-positive participants led to a rise in the upper limits of TSH in all cohorts, especially in the first (mean +17.4%; range +1.6 to +30.3%) and second trimester (mean +9.8%; range +0.6 to +32.3%). The use of the 95th percentile led to considerable changes in upper limits, varying from -10.8% to -21.8% for TSH and -1.2% to -13.2% for FT4. All other additional exclusion criteria changed reference interval cut-offs by a maximum of 3.5%. Applying these findings to the 102 studies included in the systematic review, 48 studies could be used in a clinical setting. CONCLUSION: We provide an overview of clinically relevant reference intervals for TSH and FT4 in pregnancy. The results of the meta-analysis indicate that future studies can adopt a simplified study setup without additional exclusion criteria.

Association between maternal thyroid function and risk of gestational hypertension and pre-eclampsia: a systematic review and individual-participant data meta-analysis.

BACKGROUND: Adequate maternal thyroid function is important for an uncomplicated pregnancy. Although multiple observational studies have evaluated the association between thyroid dysfunction and hypertensive disorders of pregnancy, the methods and definitions of abnormalities in thyroid function tests were heterogeneous, and the results were conflicting. We aimed to examine the association between abnormalities in thyroid function tests and risk of gestational hypertension and pre-eclampsia. METHODS: In this systematic review and meta-analysis of individual-participant data, we searched MEDLINE (Ovid), Embase, Scopus, and the Cochrane Database of Systematic Reviews from date of inception to Dec 27, 2019, for prospective cohort studies with data on maternal concentrations of thyroid-stimulating hormone (TSH), free thyroxine (FT4), thyroid peroxidase (TPO) antibodies, individually or in combination, as well as on gestational hypertension, pre-eclampsia, or both. We issued open invitations to study authors to participate in the Consortium on Thyroid and Pregnancy and to share the individual-participant data. We excluded participants who had pre-existing thyroid disease or multifetal pregnancy, or were taking medications that affect thyroid function. The primary outcomes were documented gestational hypertension and pre-eclampsia. Individual-participant data were analysed using logistic mixed-effects regression models adjusting for maternal age, BMI, smoking, parity, ethnicity, and gestational age at blood sampling. The study protocol was registered with PROSPERO, CRD42019128585. FINDINGS: We identified 1539 published studies, of which 33 cohorts met the inclusion criteria and 19 cohorts were included after the authors agreed to participate. Our study population comprised 46 528 pregnant women, of whom 39 826 (85·6%) women had sufficient data (TSH and FT4 concentrations and TPO antibody status) to be classified according to their thyroid function status. Of these women, 1275 (3·2%) had subclinical hypothyroidism, 933 (2·3%) had isolated hypothyroxinaemia, 619 (1·6%) had subclinical hyperthyroidism, and 337 (0·8%) had overt hyperthyroidism. Compared with euthyroidism, subclinical hypothyroidism was associated with a higher risk of pre-eclampsia (2·1% vs 3·6%; OR 1·53 [95% CI 1·09-2·15]). Subclinical hyperthyroidism, isolated hypothyroxinaemia, or TPO antibody positivity were not associated with gestational hypertension or pre-eclampsia. In continuous analyses, both a higher and a lower TSH concentration were associated with a higher risk of pre-eclampsia (p=0·0001). FT4 concentrations were not associated with the outcomes measured. INTERPRETATION: Compared with euthyroidism, subclinical hypothyroidism during pregnancy was associated with a higher risk of pre-eclampsia. There was a U-shaped association of TSH with pre-eclampsia. These results quantify the risks of gestational hypertension or pre-eclampsia in women with thyroid function test abnormalities, adding to the total body of evidence on the risk of adverse maternal and fetal outcomes of thyroid dysfunction during pregnancy. These findings have potential implications for defining the optimal treatment target in women treated with levothyroxine during pregnancy, which needs to be assessed in future interventional studies. FUNDING: Arkansas Biosciences Institute and Netherlands Organization for Scientific Research.

Warthin-like and classic papillary thyroid cancer have similar clinical presentation and prognosis.

OBJECTIVE: Warthin-like papillary thyroid cancer (WL-PTC) is an uncommon variant of PTC, usually associated with lymphocytic thyroiditis. Scarce evidence suggests that WL-PTC has similar clinical presentation to classic PTC (C-PTC), with no studies comparing risks of recurrence and response to treatment between both variants. Our objective was to describe the clinical presentation and prognosis of WL-PTC and compare it to C-PTC. METHODS: Retrospective analysis of a prospective cohort, including 370 (96%) patients with C-PTC and 17 (4%) with WL-PTC, consecutively treated with total thyroidectomy with or without RAI, followed for at least 6 months. We compared clinical presentation, risk of mortality and recurrence, as well as response to treatment between both variants. RESULTS: Of the total cohort: 317 (82%) female, 38 ± 13.5 years, median follow-up 4 years (0.5-28.5); most of them stage I and low/intermediate risk of recurrence. We found no differences regarding clinical-pathological data and risk of recurrence. WL-PTC was associated with a higher rate of anti-thyroglobulin antibodies (TgAb) (65% vs. 36%, p = 0.016) and lymphocytic thyroiditis (59% vs. 34%, p = 0.03). The rates of biochemical and structural incomplete responses were similar in both variants. WL-PTC had a lower rate of excellent response (23% vs. 54%, p = 0.01), which became non-significant when performing analysis by TgAb presence (50% vs. 67%, p = NS). CONCLUSION: WL-CPT and C-CPT have similar clinical presentation and rate of recurrence. The lower rate of excellent response to treatment in WL-PTC is due to a higher frequency of TgAb. WL-PCT should not be considered an aggressive variant of PTC.

Association of maternal thyroid function with birthweight: a systematic review and individual-participant data meta-analysis.

BACKGROUND: Adequate transplacental passage of maternal thyroid hormone is important for normal fetal growth and development. Maternal overt hypothyroidism and hyperthyroidism are associated with low birthweight, but important knowledge gaps remain regarding the effect of subclinical thyroid function test abnormalities on birthweight-both in general and during the late second and third trimester of pregnancy. The aim of this study was to examine associations of maternal thyroid function with birthweight. METHODS: In this systematic review and individual-participant data meta-analysis, we searched MEDLINE (Ovid), Embase, Web of Science, the Cochrane Central Register of Controlled Trials, and Google Scholar from inception to Oct 15, 2019, for prospective cohort studies with data on maternal thyroid function during pregnancy and birthweight, and we issued open invitations to identify study authors to join the Consortium on Thyroid and Pregnancy. We excluded participants with multiple pregnancies, in-vitro fertilisation, pre-existing thyroid disease or thyroid medication usage, miscarriages, and stillbirths. The main outcomes assessed were small for gestational age (SGA) neonates, large for gestational age neonates, and newborn birthweight. We analysed individual-participant data using mixed-effects regression models adjusting for maternal age, BMI, ethnicity, smoking, parity, gestational age at blood sampling, fetal sex, and gestational age at birth. The study protocol was pre-registered at the International Prospective Register of Systematic Reviews, CRD42016043496. FINDINGS: We identified 2526 published reports, from which 36 cohorts met the inclusion criteria. The study authors for 15 of these cohorts agreed to participate, and five more unpublished datasets were added, giving a study population of 48 145 mother-child pairs after exclusions, of whom 1275 (3·1%) had subclinical hypothyroidism (increased thyroid stimulating hormone [TSH] with normal free thyroxine [FT4]) and 929 (2·2%) had isolated hypothyroxinaemia (decreased FT4 with normal TSH). Maternal subclinical hypothyroidism was associated with a higher risk of SGA than was euthyroidism (11·8% vs 10·0%; adjusted risk difference 2·43%, 95% CI 0·43 to 4·81; odds ratio [OR] 1·24, 1·04 to 1·48; p=0·015) and lower mean birthweight (mean difference -38 g, -61 to -15; p=0·0015), with a higher effect estimate for measurement in the third trimester than in the first or second. Isolated hypothyroxinaemia was associated with a lower risk of SGA than was euthyroidism (7·3% vs 10·0%, adjusted risk difference -2·91, -4·49 to -0·88; OR 0·70, 0·55 to 0·91; p=0·0073) and higher mean birthweight (mean difference 45 g, 18 to 73; p=0·0012). Each 1 SD increase in maternal TSH concentration was associated with a 6 g lower birthweight (-10 to -2; p=0·0030), with higher effect estimates in women who were thyroid peroxidase antibody positive than for women who were negative (pinteraction=0·10). Each 1 SD increase in FT4 concentration was associated with a 21 g lower birthweight (-25 to -17; p<0·0001), with a higher effect estimate for measurement in the third trimester than the first or second. INTERPRETATION: Maternal subclinical hypothyroidism in pregnancy is associated with a higher risk of SGA and lower birthweight, whereas isolated hypothyroxinaemia is associated with lower risk of SGA and higher birthweight. There was an inverse, dose-response association of maternal TSH and FT4 (even within the normal range) with birthweight. These results advance our understanding of the complex relationships between maternal thyroid function and fetal outcomes, and they should prompt careful consideration of potential risks and benefits of levothyroxine therapy during pregnancy. FUNDING: Netherlands Organization for Scientific Research (grant 401.16.020).

In properly selected patients with differentiated thyroid cancer, antithyroglobulin antibodies decline after thyroidectomy and their sole presence should not be an indication for radioiodine ablation.

OBJECTIVE: Our objective was to evaluate the trend of antithyroglobulin antibodies (TgAb) during follow-up of patients with differentiated thyroid cancer (DTC) treated without RAI, as well as their role in the risk of recurrence. SUBJECTS AND METHODS: This was a prospective, descriptive study. A total of 152 consecutive patients with DTC treated in a single institution undergoing total thyroidectomy without RAI and followed for a median of 2.3 years (0.5-10.3) were divided in two groups: TgAb(-) (n = 111) and TgAb(+) (n = 41). Patients were classified according to AJCC 7th and 8th editions, as well as to their risk of recurrence and response to treatment categories. RESULTS: Both groups, TgAb(-) and TgAb(+), were similar regarding patient and tumor characteristics. At the end of follow-up, 90 (59.2%), 57 (37.5%), 3 (2%) and 2 (1.3%) patients achieved excellent, indeterminate, biochemically incomplete and structurally incomplete response, respectively. The risk of structural recurrence was similar in both groups (TgAb[-] 0.9% vs. TgAb[+] 2.4%, p = 0.46). In the TgAb(+) group, TgAb became negative in 10 (24.4%), decreased ≥ 50% without negativization in 25 (60.9%), decreased < 50% in 4 (9.8%) and remained stable or increased in 2 (4.9%) cases. The only incomplete structural response had increasing TgAb during follow-up. CONCLUSIONS: In properly selected patients with DTC, TgAb concentration immediately after total thyroidectomy should not mandate RAI ablation, and their trend during follow-up may impact the risk of recurrence.

Active surveillance is a feasible and safe strategy in selected patients with papillary thyroid cancer and suspicious cervical lymph nodes detected after thyroidectomy

ABSTRACT Objective: After initial treatment, up to 30% of patients with papillary thyroid cancer (PTC) have incomplete response, mainly cervical lymph node (LN) disease. Previous studies have suggested that active surveillance (AS) is a possible option for these patients. Our aim was to report the results of AS in patients with PTC and cervical LN disease. Materials and methods: In this retrospective observational study, we included adult patients treated and followed for PTC, who presented with cervical LN disease and were managed with AS. Growth was defined as an increase ≥ 3mm in either diameter. Results: We included 32 patients: 27 (84.4%) women, age of 39 ± 14 years, all initially treated with total thyroidectomy, and 22 (69%) with therapeutic neck dissection. Cervical LN disease was diagnosed 1 year (0.3-12.6) after initial management, with a diameter of 9.0 mm (6.0-19.0). After a median AS of 4.3 years (0.6-14.1), 4 (12.5%) patients had LN growth: 2 (50%) of whom were surgically removed, 1 (25%) was effectively treated with radiotherapy, and 1 (25%) had a scheduled surgery. Tg increase was the only predictive factor of LN growth evaluated as both the delta Tg (p < 0.0366) and percentage of Tg change (p < 0.0140). None of the included patients died, had local complications due to LN growth or salvage therapy, or developed distant metastases during follow-up. Conclusions: In selected patients with PTC and suspicious cervical LNs diagnosed after initial treatment, AS is a feasible and safe strategy as it allows effective identification and treatment of the minority of patients who progress.