Does iodine fortification affect the risk of atrial fibrillation in incident hyperthyroidism? A national register-based cohort.

Objective: Iodine fortification (IF) induces an initial increase followed by a decrease in the incidence of hyperthyroidism in the general population. Within the population of hyperthyroid patients, the sex-, age- and subtype distribution changes after IF. The risk of atrial fibrillation (AF) in hyperthyroid patients may be influenced by these factors.

Hyperthyroidism in Danish Pregnant Women During a 20-Year Period.

Context: Hyperthyroidism in pregnancy is a clinical concern, and surveillance of any change in the occurrence of hyperthyroidism in pregnancy is important, especially when a mandatory iodine fortification (IF) program is implemented such as in Denmark in the year 2000.

Objective: To investigate any change in the occurrence of hyperthyroidism and the use of antithyroid drugs (ATDs) in Danish pregnant women during a 20-year period before and after the implementation of IF.

Methods: A nationwide register-based cohort (1997-2016) and 2 birth cohorts with biochemical data (the Danish National Birth Cohort, 1997-2003, and the North Denmark Region Pregnancy Cohort, 2011-2015) were used to study maternal use of ATDs in pregnancy and frequency of early pregnancy biochemical hyperthyroidism during a 20-year period prior to and after the implementation of mandatory IF.

Hyperthyroidism in pregnancy: design and methodology of a Danish multicenter study.

Background: Graves' disease (GD) is the main cause of hyperthyroidism in women of the fertile age. In pregnant women, the disease should be carefully managed and controlled to prevent maternal and fetal complications. Observational studies provide evidence of the adverse effects of untreated hyperthyroidism in pregnancy and have in more recent years substantiated a risk of teratogenic side effects with the use of antithyroid drugs (ATDs).

Does Subclinical Hypothyroidism Add Any Symptoms? Evidence from a Danish Population-Based Study.

Background: Few studies have scrutinized the spectrum of symptoms in subclinical hypothyroidism.

Methods: From 3 Danish Investigation on Iodine Intake and Thyroid Diseases (DanThyr) cross-sectional surveys performed in the period 1997 to 2005, a total of 8903 subjects participated in a comprehensive investigation including blood samples and questionnaires on previous diseases, smoking habits, alcohol intake, and education. From the 3 surveys we included patients with subclinical hypothyroidism (n = 376) and euthyroid controls (n = 7619).

Long-term iodine nutrition is associated with longevity in older adults: a 20 years' follow-up of the Randers-Skagen study.

Iodine intake affects the occurrence of thyroid disorders. However, the association of iodine intake with longevity remains to be described. This led us to perform a 20 years' follow-up on participants from the Randers-Skagen (RaSk) study.

Increased Incidence Rate of Hypothyroidism After Iodine Fortification in Denmark: A 20-Year Prospective Population-Based Study.

Objective: To monitor the impact of a cautious iodine fortification (IF) on the incidence of overt hypothyroidism in two subpopulations with different levels of preexisting iodine deficiency (ID).

Design: A 20-year (1997 to 2016) prospective population-based study identified all new cases of diagnosed overt biochemical hypothyroidism in two open cohorts: a western cohort with moderate ID (n = 309,434; 1 January 1997) and an eastern cohort with mild ID (n = 224,535; 1 January 1997). A diagnostic algorithm was applied to all thyroid function tests performed within the study areas, and possible new cases were verified individually.

Thyrotoxicosis after iodine fortification. A 21-year Danish population-based study.

Objective: Monitoring the influence of cautious iodine fortification (IF) on the incidence rate of overt thyrotoxicosis in Denmark with formerly frequent multinodular toxic goitre.

Design: A 21-year (1997-2017) prospective population-based study identified all new cases of overt biochemical thyrotoxicosis in two open cohorts: a Western cohort with moderate iodine deficiency (ID) and an Eastern cohort with mild ID (total n = 533 969 by 1 January 1997). A diagnostic algorithm was applied to all thyroid function tests performed within the study areas.

Comparison of three competitive immunoassays for measurement of TSH receptor antibodies in patients with Graves' disease.

Thyrotropin (TSH) receptor antibodies (TRAb) mediate the hyperthyroidism of Graves' disease (GD). The aim of the study was to compare the diagnostic performance and assay agreement between three immunoassays for the measurement of TRAb in patients with newly diagnosed GD. TRAb was measured with three different assays [H-TRAb (BRAHMS Diagnostica), M22-Man (RSR Limited) and M22-Aut (Roche Diagnostics)] in 387 participants who were recruited from two Danish population-based studies and diagnosed with GD (n = 101), multinodular toxic goitre (n = 88), primary autoimmune hypothyroidism (n = 100) or included as controls (n = 98).

MECHANISMS IN ENDOCRINOLOGY: Neurodevelopmental disorders in children born to mothers with thyroid dysfunction: evidence of fetal programming?

Fetal programming is a long-standing, but still evolving, concept that links exposures during pregnancy to the later development of disease in the offspring. A fetal programming effect has been considered within different endocrine axes and in relation to different maternal endocrine diseases. In this critical review, we describe and discuss the hypothesis of fetal programming by maternal thyroid dysfunction in the context of fetal brain development and neurodevelopmental disorders in the offspring.

Hypothyroid Symptoms Fail to Predict Thyroid Insufficiency in Old People: A Population-Based Case-Control Study.

Background: Clinic-based studies have indicated that older hypothyroid patients may present only few symptoms.

Methods: In this population-based study of hypothyroidism, we investigated how the power of symptom presence predicts overt hypothyroidism in both young and older subjects. We identified patients newly diagnosed with overt autoimmune hypothyroidism in a population (n = 140, median thyroid-stimulating hormone, 54.

Can Elastography Predict Growth of Incidental Thyroid Nodules? A Pilot Two-Year Follow-Up Study.

The objective of this study was to examine the ultrasonography (US) and ultrasound elastography (USE) features of thyroid incidentalomas in a population exposed to iodine deficiency and to investigate whether baseline elasticity scores (ES) predicted changes in thyroid nodule US characteristics. We conducted a two-year follow-up pilot study of thyroid incidentalomas by US and USE. One sonographer performed the US and USE examination on the same apparatus at baseline and at follow-up.

Serum thyroglobulin before and after iodization of salt: an 11-year DanThyr follow-up study.

Objective: Our objective was to investigate individual serum thyroglobulin (Tg) changes in relation to iodine fortification (IF) and to clarify possible predictors of these changes.

Design: We performed a longitudinal population-based study (DanThyr) in two regions with different iodine intake at baseline: Aalborg (moderate iodine deficiency (ID)) and Copenhagen (mild ID). Participants were examined at baseline (1997) before the mandatory IF of salt (2000) and again at follow-up (2008) after IF.

Gender differences in symptoms of hypothyroidism: a population-based DanThyr study.

Objectives: We examined the gender-specific symptom prevalences in hypothyroidism and in healthy controls and explored the extent to which symptoms indicative of thyroid status may be different in women and men.

Design And Methods: Patients newly diagnosed with overt autoimmune hypothyroidism (n = 140) and controls free of thyroid disease (n = 560) recruited from the same population participated in a population-based study of The Danish Investigation of Iodine Intake and Thyroid Diseases (DanThyr). Participants underwent a comprehensive programme including blood tests and completion of questionnaires.

Double vision is a major manifestation in moderate to severe graves' orbitopathy, but it correlates negatively with inflammatory signs and proptosis.

Context: Double vision (diplopia) is a major determinant of work disability in patients with Graves' orbitopathy (GO), but is not part of the classification NOSPECS classification of GO.

Objective: The objectives of the study were to quantitate diplopia in patients with moderate to severe GO and to study associations with other disease and patient variables.

Design: This was a single-center prospective study of consecutive patients at the time of referral.

Hypothyroid symptoms and the likelihood of overt thyroid failure: a population-based case-control study.

Background: It is generally accepted that patients suffering from hypothyroidism may express few symptoms, but this has not been studied in a population-based study design.

Objectives: To study the array of symptoms as they are reported in newly diagnosed overt autoimmune hypothyroidism using a population-based case-control design.

Methods: Patients with new overt autoimmune hypothyroidism (n=140) and their individually matched thyroid disease-free controls (n=560) recruited from the same population underwent a comprehensive program and self-reported a number of symptoms.

Thyroid nodules in an 11-year DanThyr follow-up study.

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).

Association between TSH-Receptor Autoimmunity, Hyperthyroidism, Goitre, and Orbitopathy in 208 Patients Included in the Remission Induction and Sustenance in Graves' Disease Study.

Background. Graves' disease may have a number of clinical manifestations with varying degrees of activity that may not always run in parallel. Objectives.

Development of autoimmune overt hypothyroidism is highly associated with live births and induced abortions but only in premenopausal women.

Context: The 1-year postpartum period is often accompanied by increased risk for thyroid disease.

Objective: The objective of the study was to investigate the role of reproductive risk factors in the development of autoimmune overt hypothyroidism in the years after the 1-year postpartum period.

Design, Setting, And Subjects: In a population study, we included Danish women with new autoimmune overt hypothyroidism not diagnosed within the first year after a pregnancy (n = 117; median age 53.

Iodine fortification may influence the age-related change in thyroid volume: a longitudinal population-based study (DanThyr).

Objective: To assess the individuals' thyroid volume changes after the mandatory nationwide iodine fortification (IF) program in two Danish areas with different iodine intake at baseline (Copenhagen, mild iodine deficiency (ID) and Aalborg, moderate ID).

Design: A longitudinal population-based study (DanThyr).

Methods: We examined 2465 adults before (1997) and after (2008) the Danish IF of salt (2000).

Mandatory iodine fortification of bread and salt increases iodine excretion in adults in Denmark - a 11-year follow-up study.

Background & Aims: Iodine fortification is widespread. Systematic monitoring of iodine fortification programs should be carried out to secure an optimal fortification level. Our aim was to investigate the effectiveness of the Danish iodine fortification program by comparing iodine excretion at baseline and at 11-year follow-up, and to study determinants for any change in iodine intake including dietary habits, education, life style factors and health parameters.

Determinants of serum T4 and T3 at the time of diagnosis in nosological types of thyrotoxicosis: a population-based study.

Objective: To characterize thyroid hormone levels at the time of diagnosis in the nosological types of thyrotoxicosis diagnosed in the population and to analyze determinants for serum thyroxine (T4) and tri-iodothyronine (T3).

Design: Population-based study of thyrotoxicosis at disease onset.

Methods: In the period 1997-2000, we prospectively identified all patients diagnosed with incident primary overt thyrotoxicosis in a Danish population cohort and classified patients into ten well-defined nosological types of disease (n=1082).

High age predicts low referral of hyperthyroid patients to specialized hospital departments: evidence for referral bias.

Background: Hospital-based studies may be hampered by referral bias. We investigated how the phenomenon may influence studies of hyperthyroid patients.

Methods: By means of a computer-based linkage to the laboratory database and subsequent detailed evaluation of subjects with abnormal test results, we prospectively identified all 1148 patients diagnosed with overt hyperthyroidism in a four-year period in and around Aalborg City, Denmark.

Screening for overt thyroid disease in early pregnancy may be preferable to searching for small aberrations in thyroid function tests.

Thyroid hormones are important regulators of foetal development, and in recent years, there has been much focus on the screening and treatment of pregnant women for even small aberrations in thyroid function tests. We searched PubMed for publications on thyroid function and pregnancy outcomes including child cognition, and included references from the retrieved articles. Both small aberrations in thyroid function tests in early pregnancy and an increase in risk of pregnancy complications may be caused by a functional change in the uteroplacental unit.

Thyroid function and obesity.

Important interaction exists between thyroid function, weight control, and obesity. Several mechanisms seem to be involved, and in studies of groups of people the pattern of thyroid function tests depends on the balance of obesity and underlying thyroid disease in the cohort studied. Obese people with a normal thyroid gland tend to have activation of the hypothalamic-pituitary-thyroid axis with higher serum TSH and thyroid hormones in serum.