The Danish investigation on iodine intake and thyroid disease (DanThyr): history and implications.

Due to mild-to-moderate iodine deficiency in Denmark, health authorities initiated a voluntary iodine fortification (IF) program in 1998, which became mandatory in 2000. In line with recommendations from the World Health Organization, the Danish investigation on iodine intake and thyroid disease (DanThyr) was established to monitor the effect on thyroid health and disease. The program involved different study designs and followed two Danish sub-populations in the years before IF and up till 20 years after.

Cut-offs for thyroid peroxidase and thyroglobulin antibodies in early pregnancy.

Objective: Thyroid disease in women of reproductive age is mainly of autoimmune origin, and thyroid peroxidase antibodies (TPO-Ab) as well as thyroglobulin antibodies (Tg-Ab) are key markers. Adding to this, much focus in pregnancy is on euthyroid women who are thyroid antibody positive. Evidence to substantiate the cut-offs for the definition of thyroid autoantibody positivity in early pregnant women is warranted.

Long-term methimazole therapy in Graves' hyperthyroidism and adverse reactions: a Danish multicenter study.

Purpose: In this prospective multicenter study with patients newly diagnosed with Graves' hyperthyroidism (GH), we studied the timing and characteristics of adverse drug reactions in patients treated with anti-thyroid drugs (ATD) for up to 48 months.

Methods: Patients with GH were treated with ATD until remission and hereafter with a low-dose regime to keep the patients in remission. The patients were followed with blood samples and recording of adverse events approximately every second month for the first 2 years and every third month for the following 2 years.

Thyroid autoimmunity in Greenlandic Inuit.

Objective: This study aimed to provide the first data on the occurrence of thyroid autoimmunity among Inuit in Greenland, a distinct ethnic group who is not iodine deficient.

Design: This study is a population-based cross-sectional study.

Methods: Data were collected in Nuuk in West Greenland and in Ammassalik district in East Greenland.

Prevalence and predictors of adequate treatment of overt hypothyroidism - a population-based study.

The aim of this study is to evaluate the adequacy of treatment, and to identify factors influencing treatment of hypothyroidism. Patients newly diagnosed with overt hypothyroidism (=345) were identified via a register linked to a laboratory database. In selected periods with staff available, 165 patients were invited, and 113 (68.

Adaptation to a High Iodine Intake in Greenland Inuit Suggested by Thyroid Disease Pattern.

Arctic living is influenced by cold winters, short summers, and excessive iodine intake from the traditional Inuit diet providing for habitation of the Arctic for centuries. This is changing and we surveyed thyroid function in populations living in Greenland. Population-based cross-sectional study.

Changes in subtypes of overt thyrotoxicosis and hypothyroidism following iodine fortification.

Objective: To investigate the impact of mandatory iodine fortification (IF) on the incidence of nosological subtypes of overt thyrotoxicosis and hypothyroidism.

Design: We identified and scrutinized all possible new cases of overt thyrotoxicosis and hypothyroidism in an open cohort in Northern Jutland (n = 309 434; 1 January 1997) during the years 2014-2016. Individual medical history was evaluated to verify and detail the incidence of overt thyroid dysfunction and for classification into nosological subtypes.

Previous Live Births and Induced Abortions May Precede Later Development of Graves' Hyperthyroidism.

Objective: To investigate the association between reproductive history and later development of various nosological subtypes of overt hyperthyroidism.

Study Design: From the Danish population, we included incident hyperthyroid women, and for each case we recruited 4 euthyroid age-sex-region-matched controls from the same sub-population. Hyperthyroid cases/controls were: Graves' disease (GD, = 232/928), multinodular toxic goitre (MNTG, = 91/364), solitary toxic adenoma (STA, = 21/84).

Pregnancy Week-Specific Reference Ranges for Thyrotropin and Free Thyroxine in the North Denmark Region Pregnancy Cohort.

Background: Physiological changes in maternal thyroid function during pregnancy necessitate the use of pregnancy-specific reference ranges. Dynamic changes in thyrotropin (TSH) within the first trimester of pregnancy have been reported, but more evidence is needed to substantiate the findings. The objective of this study was to estimate pregnancy week-specific reference ranges for maternal TSH and free thyroxine (fT4) in early pregnancy.

Predictors of Initial and Sustained Remission in Patients Treated with Antithyroid Drugs for Graves' Hyperthyroidism: The RISG Study.

To study predictors of attaining (part 1) and sustaining (part 2) remission in patients with Graves' hyperthyroidism (GH) treated with antithyroid drugs (ATD). In the prospective first part, the included patients were treated with ATD until a prespecified definition of remission (thyrotropin > 0.4 mU/L and TSH-receptor antibodies (TRAb) ≤ 1.

Biochemical Hyperthyroidism in a Newborn Baby Caused by Assay Interaction from Biotin Intake.

We describe a case of biochemical neonatal thyrotoxicosis caused by biotin supplementation. Biotin may interact with thyroid function testing to imitate thyrotoxicosis with low thyroid-stimulating hormone and elevated triiodothyronine and thyroxine levels.

Serum thyroglobulin as a biomarker of iodine deficiency in adult populations.

Objective: To clarify which factors may influence the serum Tg level in an adult population and how this may affect Tg as a biomarker of iodine deficiency (ID).

Design And Methods: Two identical cross-sectional studies were performed before (C1a: 1997-98, n = 4649) and after (C2: 2004-05, n = 3570) the Danish mandatory iodine fortification (IF) of salt (2000). Additionally, a follow-up study of C1a was performed after IF (C1b: 2008-10, n = 2465).

Parity and 11-Year Serum Thyrotropin and Thyroid Autoantibody Change: A Longitudinal Population-Based Study.

Background: A role for female reproductive factors in the pathogenesis of thyroid autoimmunity has been suggested. This study investigated the prospective association between parity, abortion, use of oral contraceptive pill (OCP), and use of hormone replacement therapy (HRT), and 11-year change in serum thyrotropin (TSH), as well as change in thyroid peroxidase autoantibody (TPOAb) status.

Methods: A random sample of 4649 people aged 18-65 years participated in a population-based study in the period 1997-1998.

Serum selenium is low in newly diagnosed Graves' disease: a population-based study.

Context: Selenium deficiency may play an important role in the initiation and progression of autoimmune thyroid disease.

Objective: To compare serum selenium (s-Se) values in patients with newly diagnosed autoimmune thyroid disease and controls from the Danish population.

Design And Settings: S-Se was measured in triplicate by a fluorimetric method.

Graves' hyperthyroidism and moderate alcohol consumption: evidence for disease prevention.

Background: We recently demonstrated that moderate alcohol consumption is associated with a considerable reduction in the risk of autoimmune hypothyroidism, similar to findings in other autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. We aimed to study a possible association between alcohol intake and autoimmune Graves' hyperthyroidism.

Design: This is a population-based, case-control study.

Predictors of change in serum TSH after iodine fortification: an 11-year follow-up to the DanThyr study.

Context: Few data are available on the effect of iodine fortification on thyroid function development in a population.

Objective: Our objective was to evaluate changes in thyroid function after iodine fortification in a population and to identify predictors for changes in serum TSH.

Design And Setting: A longitudinal population-based study of the DanThyr C1 cohort examined at baseline (1997-1998) and reexamined 11 yr later (2008-2010).

Smoking cessation is followed by a sharp but transient rise in the incidence of overt autoimmune hypothyroidism - a population-based, case-control study.

Background: Current smoking is associated with a low prevalence of thyroid autoantibodies. On the other hand, smoking withdrawal enhances thyroid autoantibody level and may be a risk factor for the development of hypothyroidism. The aim of this study was to assess the association between smoking habits (smoking cessation in particular) and development of autoimmune hypothyroidism.

Incidence and clinical presentation of moderate to severe graves' orbitopathy in a Danish population before and after iodine fortification of salt.

Context: Population-based data on the incidence and clinical presentation of moderate to severe Graves' orbitopathy (GO) are scarce, and virtually nothing is known on the effect of an iodization program on the incidence and presentation of GO.

Objective: The objective of the study was to characterize incident moderate to severe GO in North Jutland County, Denmark, during the period 1992-2009, before and after the Danish salt iodization program.

Design And Patients: The design of the study was a prospective register of patients with incident moderate to severe GO in a population during 8.

Sustained control of Graves' hyperthyroidism during long-term low-dose antithyroid drug therapy of patients with severe Graves' orbitopathy.

Background: Patients with severe Graves' orbitopathy often have hyperthyroidism that is difficult to treat and a high proportion of patients experience relapse of hyperthyroidism after a course of antithyroid drug (ATD) therapy of fixed duration. The aim of the study was to evaluate the feasibility of prolonged low-dose ATD therapy for attaining stable euthyroidism in patients with severe Graves' orbitopathy and hyperthyroidism.

Methods: We performed retrospective analyses of data collected during observation of a cohort of patients (n = 108) treated for severe Graves' orbitopathy and for hyperthyroidism using partial block with low-dose thionamide + replacement with levothyroxine (L-T4) for >2 years.

Increase in incidence of hyperthyroidism predominantly occurs in young people after iodine fortification of salt in Denmark.

Context: To prevent goiter and nodular hyperthyroidism, iodine fortification (IF) of salt was introduced in Denmark in 1998. We prospectively registered all new cases of overt hyperthyroidism in two areas of Denmark before and for the first 6 yr after iodine fortification.

Methods: We used a computer-based register of all new cases of hyperthyroidism in two population subcohorts with moderate iodine deficiency (Aalborg, n = 310,124) and mild iodine deficiency (Copenhagen, n = 225,707), respectively.

Lack of association between thyroid autoantibodies and parity in a population study argues against microchimerism as a trigger of thyroid autoimmunity.

Background: Thyroid autoimmunity is more common in females than in males. One possible explanation for this female preponderance may be the effect of oestrogens on the immune system. It has also been suggested that foetal microchimerism involving transfer of foetal cells into maternal tissue during pregnancy may play an important role.

A population study of the association between thyroid autoantibodies in serum and abnormalities in thyroid function and structure.

Objective: Patients with autoimmune overt hypothyroidism may present with goitrous Hashimoto's disease or autoimmune atrophic thyroiditis. Little is known about the prevalence of subclinical autoimmune hypothyroidism. The aims of this study were to evaluate the association between thyroid autoantibodies in serum and abnormalities in thyroid function and structure, and to study the thyroid volume in subjects with subclinical autoimmune hypothyroidism.

Hypothyroidism in the elderly: pathophysiology, diagnosis and treatment.

Some degree of hypothyroidism is common in the elderly. It affects 5-20% of women and 3-8% of men. The occurrence varies with genetics with a high prevalence in Caucasians, and the disease is more common in populations with a high iodine intake.

Thiocyanate in food and iodine in milk: from domestic animal feeding to improved understanding of cretinism.

Transport of iodine in the mammary gland into breast milk plays a central role in various fields of prevention of thyroid diseases. First, a sufficient content of iodine in the mother's milk is necessary for normal brain development in the breastfed child. This is attained by expression during lactation in the mammary gland of the sodium iodide symporter (NIS), also responsible for iodine transport in the thyroid.

Large differences in incidences of overt hyper- and hypothyroidism associated with a small difference in iodine intake: a prospective comparative register-based population survey.

Around 3-4 billion people in the world are covered by iodine supplementation programs to prevent developmental brain damage and other iodine deficiency (ID) disorders. Mild ID is associated with more hyperthyroidism and less hypothyroidism in the population than a high iodine intake. Knowledge of the iodine intake levels where the shifts in incidences occur is important for planning of iodine supplementation programs.