Improving Health and Diabetes Self-Management in Immigrants with Type 2 Diabetes Through a Co-Created Diabetes Self-Management Education and Support Intervention.

To examine the impact of a co-created culturally sensitive diabetes self-management education and support (DSMES) intervention on the physical and mental health of immigrants with type 2 diabetes (T2D). Pre- and post-test among people with T2D whose primary language was Urdu, Arabic or Turkish (n = 97). Participants were offered a six-week intervention based on a person-centred approach using research-based dialogue tools to facilitate learning and reflection, which was developed in co-creation with immigrants and healthcare professionals. Data were collected at baseline, post-intervention and after 6 months and analysed using paired t-tests, Wilcoxon signed-rank tests, chi-square tests and regression models when appropriate. Several clinical outcomes were improved post-intervention, including HbA1c (P < 0.001), body fat percentage (P = 0.002), self-rated general health (P = 0.05), well-being (P = 0.004) and several self-management behaviours, e.g., physical activity (P < 0.001). Most outcomes remained improved after 6 months, but the effect on HbA1c was no longer statistically significant. Some outcomes were improved only at 6 months, including waist circumference (P < 0.001) and diabetes-related emotional distress (P < 0.001). Fatigue did not change. Attendance at more programme sessions was associated with better outcomes. The DSMES intervention developed in a co-creation process was highly effective in improving the health of immigrants with T2D.

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. Mandatory IF of salt was initiated in mid-2000 (13 ppm). This study is a part of DanThyr. RESULTS: The standardized incidence rate (SIR) of thyrotoxicosis at baseline (1997-1998) was 128.5/100.000/year in the cohort with moderate ID and 80.1 in the cohort with mild ID. SIR increased markedly in both cohorts during the initial years of IF (moderate/mild ID: +39/+52% in 2000-2001/2004-2005) and subsequently decreased to baseline level (mild ID) or below (moderate ID) by 2008. The decline was due to a marked decrease in the incidence rate among elderly subjects and a moderate decrease among the middle aged. The follow-up period for the mildly iodine deficient cohort was restricted to 2008. A continuous decline in SIR was observed for the remainder of the study period in the area with moderate ID (33% below baseline in 2016-2017). CONCLUSION: The rise in thyrotoxicosis incidence with cautious mandatory IF returned to baseline level after 7-8 years and levelled out at 33% below baseline in the population with previously moderate ID after 16-17 years.

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. Results showed that the IF was successfully implemented and increased the level of iodine intake from mild-moderate iodine deficiency to low adequacy. The level of thyroglobulin and thyroid volume decreased following IF, and there was an indication of fewer thyroid nodules. The incidence of hyperthyroidism increased transiently following IF but subsequently decreased below the pre-fortification level. Conversely, thyroid-stimulating hormone levels and the prevalence of thyroid autoimmunity increased along with an increase in the incidence of hypothyroidism. These trends were mirrored in the trends in treatments for thyroid disease. Most differences in thyroid health and disease between regions with different iodine intake levels before IF attenuated. This review illustrates the importance of a monitoring program to detect both beneficial and adverse effects and exemplifies how a monitoring program can be conducted when a nationwide health promotion program - as IF - is initiated.

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. PARTICIPANTS: Patients with newly diagnosed Graves' disease (GD) (n = 97) or autoimmune overt hypothyroidism (AIH) (n = 96), euthyroid subjects with high serum levels of thyroid peroxidase antibody (TPO-Ab) (TPO-Ab > 1500 U/ml, n = 92) and random controls (n = 830). MAIN OUTCOME MEASURE: Differences in s-Se values. RESULTS: S-Se was lower in patients with GD than in controls (mean (SD), GD: 89·9 µg/l (18·4); controls: 98·8 µg/l (19·7), P < 0·01). This was confirmed in a multivariate logistic regression model adjusting for age, sex, mineral supplements, smoking, geographical region and time of sampling (P < 0·01). In a linear model, s-Se was similar in patients with AIH (mean (SD): 98·4 µg/l (24·9)) and in controls (P = 0·86). In the multivariate model however, s-Se was marginally lower in patients with AIH compared to controls (P = 0·04). There was no significant difference in s-Se between euthyroid participants with high TPO-Ab and random controls (linear: P = 0·97; multivariate: P = 0·27). CONCLUSION: Patients with newly diagnosed GD and AIH had significantly lower s-Se compared with random controls. Our observation supports the postulated link between inadequate selenium supply and overt autoimmune thyroid disease, especially GD.

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. METHODS: In a well-defined Danish population (2,027,208 person-years of observation), we prospectively identified patients with new overt thyroid dysfunction and studied 272 patients with Graves' hyperthyroidism. For each patient, we recruited four age-gender-region-matched controls with normal thyroid function (n = 1088). MEASUREMENTS: Participants gave detailed information on current and previous alcohol intake as well as other factors to be used for analyses. The association between alcohol intake and development of hyperthyroidism was analysed in conditional multivariate Cox regression models. RESULTS: Graves' patients had a lower reported alcohol consumption than controls (median units of alcohol (12 g) per week: 2 vs 4, P < 0·001). In a multivariate regression model, alcohol consumption was associated with a dose-dependent reduction in risk for development of overt Graves' hyperthyroidism. Odds ratios (95% confidence interval) compared with the reference group with a recent (last year) consumption of 1-2 units of alcohol per week were as follows: 0 units/week 1·73 (1·17-2·56), 3-10 units/week 0·56 (0·39-0·79), 11-20 units/week 0·37 (0·21-0·65), ≥21 units/week 0·22 (0·08-0·60). Similar results were found for maximum previous alcohol consumption during a calendar year. No interaction was found with the type of alcohol consumed (wine vs beer), smoking habit, age, gender or region of inhabitancy. CONCLUSIONS: Moderate alcohol consumption is associated with a considerable reduction in the risk of Graves' disease with hyperthyroidism--irrespective of age and gender. Autoimmune thyroid disease seems to be much more dependent on environmental factors than hitherto anticipated.

Doubling in the use of thyroid hormone replacement therapy in Denmark: association to iodization of salt?

Iodization of salt is an effective strategy to prevent iodine deficiency disorders. Recent studies, however, indicate that increasing the iodine intake in a population may give rise to an increased incidence of hypothyroidism, but the association has not been fully clarified. In Denmark, iodization of salt was initiated in 1998 because of mild-to-moderate iodine deficiency. The aim of this study was to evaluate the effect of the raised iodine intake on the nationwide incident use of thyroid hormone replacement therapy (levothyroxine) to treat hypothyroidism. Data on all use of levothyroxine was extracted from the Register of Medicinal Product Statistics during the period 1995-2009 and linked to other nationwide registers by use of the Danish identification number. Persons with previous thyroid surgery were excluded. In the studied period 71,565 incident users were identified. The incidence rate increased 75% in the moderately iodine deficient region (72.2 incident users/100,000 person-years in 1997 to 126.6 in 2008) and 87% in the mildly deficient region (86.9-162.9). When stratified by sex and age-group (00-39, 40-64, 65+) the largest relative increase was seen among women in the youngest age-group, where more than a doubling was seen. The mechanisms behind the increase may be a result of iodine-induced hypothyroidism, although a higher diagnostic activity with regard to thyroid dysfunction and intensified treatment of subclinical hypothyroidism may also play a role. Our findings stress the need for caution when initiating iodine fortification programs to keep the intake within the optimal range, and the need for continuous monitoring.

Stagnation in body mass index in Denmark from 1997/1998 to 2004/2005, but with geographical diversity.

INTRODUCTION: We analyzed the trend in body mass index (BMI) as well as in the prevalence of overweight and obesity among Danish adults, mainly women, from 1997/1998 to 2004/2005 and evaluated any regional differences. MATERIAL AND METHODS: Data were drawn from two cross-sectional population-based studies conducted in parallel in Aalborg and Copenhagen from 1997/1998 and 2004/2005. Height and weight were measured in a total of 7,487 participants in the two cohorts. RESULTS: In the total cohort, we found no significant difference in BMI from 1997/1998 to 2004/2005 (p = 0.828). There was an increase in BMI in Aalborg of 0.32 (p = 0.030), while in Copenhagen we observed a statistically significant decrease in BMI of 0.30 (p = 0.017). The difference in change over time in BMI between the two regions was significant (p = 0.002). Also the difference in the trend in prevalence of overweight and obesity was statistically significant between the two cities (p = 0.010). CONCLUSION: Our results indicate that the obesity epidemic is leveling off - at least among women - and that it may even be receding in Copenhagen. Nevertheless, the absolute average BMI values and the prevalence of overweight and obesity in both cities are high which underlines the need for further initiatives to prevent obesity-related health risks in the future. FUNDING: The DanThyr studies were supported by funding from the Tømmerhandler Vilhelm Bang Foundation, the Copenhagen Corporation Research Foundation, the 1991 Pharmacy Foundation, the Danish Medical Foundation, the Health Insurance Foundation, the Agnes and Knut Mørk Foundation, the Wedel Wedelsborg Foundation, the Ortho-Clinical Foundation and BRAHMS Diagnostica. TRIAL REGISTRATION: not relevant.

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). We explored to what extent patients with subclinical hypothyroidism reported 13 previously identified hypothyroidism-associated symptoms (tiredness, dry skin, mood lability, constipation, palpitations, restlessness, shortness of breath, wheezing, globus sensation, difficulty swallowing, hair loss, dizziness/vertigo, and anterior neck pain). In various uni- and multivariate regression models we searched for circumstances predicting why some patients have more complaints than others. RESULTS: Subclinically hypothyroid patients did not report higher hypothyroidism score [(median, interquartile range), 2 (0-4) vs 2 (0-4), P = .25] compared with euthyroid controls. Within the group of subclinical hypothyroid patients, comorbidity had the highest impact on symptoms (tiredness, shortness of breath, wheezing; all P < .001); TSH level had no impact on symptom score; and younger age was accompanied by higher mental burden (tiredness, P < .001; mood lability, P < .001; restlessness, P = .012), whereas shortness of breath was associated with high body mass index (P < .001) and smoking (P = .007). CONCLUSION: Patients with a thyroid function test suggesting subclinical hypothyroidism do not experience thyroid disease-related symptoms more often than euthyroid subjects. In subclinical hypothyroidism, clinicians should focus on concomitant diseases rather than expecting symptomatic relief following levothyroxine substitution.

Improving empowerment, motivation, and medical adherence in patients with poorly controlled type 2 diabetes: A randomized controlled trial of a patient-centered intervention.

OBJECTIVE: To test whether an intervention consisting of four patient-centered consultations improves glycemic control and self-management skills in patients with poorly regulated type 2 diabetes (T2DM), compared to a control group receiving usual care. METHODS: Unblinded parallel randomized controlled trial including 97 adults diagnosed with T2DM ≥ 1 year and hemoglobin A1c (HbA1c) levels ≥ 8.0% (64 mmol/mol). Consultations incorporated tools supporting self-reflection, learning processes, and goal setting. Primary outcome was HbA1c. Secondary outcomes were autonomy support, motivation, self-management skills, and well-being. RESULTS: Average HbA1c decreased slightly in both groups. Autonomy support and frequency of healthy eating were significantly higher in the intervention group. Most participants in the intervention group chose to set goals related to diet and physical exercise. Implementation of the intervention was inconsistent. CONCLUSION: Despite increased autonomy support and individual goal-setting, the intervention was not superior to usual care in terms of glycemic control. More research is needed on how individual preferences and goals can be supported in practice to achieve sustainable behavior changes. PRACTICE IMPLICATIONS: The intervention promoted participant engagement and supported exploration of participants' challenges and preferences. Further exploration of more flexible use of tools adapted to individual contexts is recommended.

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. Mandatory IF of salt was initiated in mid-2000 (13 ppm). The current study is a part of the DanThyr study. RESULTS: At baseline, standardized incidence rates (SIRs) of hypothyroidism were 32.9 and 47.3/100.000/y in the cohorts with moderate and mild ID, respectively. The SIR of hypothyroidism increased significantly in both cohorts after implementing mandatory IF, with peak values of 150% in 2014 to 2016 for the moderate ID cohort and 130% in 2004 to 2005 for the mild ID cohort. Significant increases in SIR were seen among the young and middle-aged participants of both cohorts, whereas no changes were seen among the elderly participants (≥60 years). The follow-up period for the mildly iodine-deficient cohort was restricted up to and including 2008. CONCLUSION: The cautious initiation of the IF program in Denmark caused a sustained increase in hypothyroidism incidence among subjects residing in areas of moderate and mild ID but only among the young and middle-aged participants.

An increased incidence of overt hypothyroidism after iodine fortification of salt in Denmark: a prospective population study.

CONTEXT: Iodine fortification (IF) of salt was introduced in Denmark in 1998. Little is known about the effect of a minor increase in iodine intake on the incidence of hypothyroidism. We prospectively identified all new cases of overt hypothyroidism in two areas of Denmark before and for the first 7 yr after IF had been introduced. METHODS: A computer-based register was used to identify continuously all new cases of overt hypothyroidism in two subcohorts with previous moderate and mild iodine deficiency (ID), respectively (Aalborg, n = 310,124, urinary iodine = 45 microg/liter; and Copenhagen, n = 225,707, urinary iodine = 61 microg/liter). Data were obtained 1) before IF (1997-1998), 2) during voluntary IF (1999-2000), 3) during early (2001-2002) and 4) during late (2003-2005) period with mandatory IF. RESULTS: The overall incidence rate of hypothyroidism increased during the study period: baseline, 38.3/100,000.yr; voluntary IF, 43.7 (not significant vs. baseline); early mandatory IF, 48.7 [vs. baseline, rate ratio (RR) = 1.27; 95% confidence interval (CI) = 1.10-1.47]; and late mandatory IF, 47.2 (vs. baseline, RR = 1.23; 95% CI = 1.07-1.42). There was a geographic difference because hypothyroidism increased only in the area with previous moderate ID: Aalborg, late mandatory IF vs. baseline, 40.3/29.7 (RR = 1.11; 95% CI = 1.11-1.66); Copenhagen, 56.7/51.6 (RR = 1.10; 95% CI = 0.90-1.34). The increase occurred in young and middle-aged adults. CONCLUSION: Even a cautious iodization of salt was accompanied by a moderate increase in the incidence rate of overt hypothyroidism. This occurred primarily in young and middle-aged subjects with previous moderate ID.

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. Data were obtained 1) before IF (1997-1998); 2) during voluntary IF (1999-2000); 3) during the early (2001-2002) period of mandatory IF; and 4) during the late (2003-2004) period with mandatory IF. RESULTS: The overall incidence rate of hyperthyroidism increased [baseline, 102.8/100,000/year; voluntary IF, 122.8; early mandatory IF, 140.7; late mandatory IF, 138.7 (P for trend <0.001)]. Hyperthyroidism increased in both sexes (P < 0.001) and in all age groups: 0-19, 20-39, 40-59, and 60+ yr (P for trend <0.001). The increase was relatively highest in young adults aged 20-39 yr: late mandatory IF (percent increase from baseline), age 20-39, 160%, P < 0.001; age 40-59, 29%, P < 0.01; age 60+ yr, 13%, P = not significant. CONCLUSION: Even a cautious iodization of salt results in an increase in the incidence rate of hyperthyroidism. Contrary to current concepts, many of the new cases were observed in young subjects, and are presumably of autoimmune origin. Furthermore, monitoring is expected to show a decrease in the number of elderly subjects suffering from nodular hyperthyroidism.

Epidemiology of subtypes of hypothyroidism in Denmark.

OBJECTIVE: Studies of hypothyroidism are often based on referred patients, and limited information is available on the incidence rates of subtypes of hypothyroidism in the general population. We therefore studied incidences of subtypes of primary, overt hypothyroidism in a Danish population cohort and compared incidences in two subcohorts with different levels of iodine intake. DESIGN: A prospective population-based study, monitoring a well-defined cohort representative of the Danish population. METHODS: The Danish Investigation of Iodine Intake and Thyroid Diseases registry of hyper- and hypothyroidism was established as part of the monitoring of the iodine fortification of salt in Denmark. A computer-based system linked to laboratory databases identified all patients diagnosed with new, biochemically overt hypothyroidism in populations living in Aalborg (moderate iodine deficiency, n = 311,102) and Copenhagen (mild iodine deficiency, n = 227,632). We subsequently evaluated all identified patients to verify incident thyroid disease, and subclassified hypothyroidism into nosological types. RESULTS: During a 4-year period (2,027,208 person-years) 685 new cases of overt hypothyroidism were diagnosed in the cohort; the incidence rate was 32.8 per 100,000 person-years (standardised to the Danish population). Nosological types of hypothyroidism were: spontaneous (presumably autoimmune) 84.4%, post-partum 4.7%, amiodarone-associated 4.0%, subacute thyroiditis 1.8%, previous radiation or surgery 1.8%, congenital 1.6% and lithium-associated 1.6%. Crude incidence rates were 29.0 around Aalborg and 40.6 in an area of Copenhagen. The higher incidence rate of hypothyroidism in the area with higher iodine intake was caused solely by more cases of spontaneous (presumably autoimmune) hypothyroidism, whereas the incidence of non-spontaneous hypothyroidism (all types combined) was significantly lower in the area with higher iodine intake. CONCLUSION: In a population-based study we observed a higher incidence of hypothyroidism with higher iodine intake. This was due solely to the entity of spontaneous hypothyroidism. The occurrence of overt hypothyroidism was relatively low in Denmark.

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. OBJECTIVE: We investigated the association between the presence of circulating thyroid autoantibodies and previous pregnancy, parity and the use of oral contraceptives (OCs) and hormone replacement therapy (HRT) in a population cohort. METHODS: We examined 3712 women randomly selected from the general population. Serum was analysed for thyroid peroxidase antibody (TPO-Ab) and thyroglobulin antibody (Tg-Ab) using assays based on an RIA technique (DYNO test). Data were analysed in logistic regression models to adjust for possible confounders. Women previously treated for thyroid disease or with pregnancy within 1 year prior to the study were excluded from the analyses. RESULTS: In both univariate and multivariate models and whether the presence of TPO-Ab and Tg-Ab was investigated alone or in combination, findings were negative with respect to an association between circulating thyroid antibodies and previous pregnancy, number of pregnancies, parity and previous abortion. There was no association between thyroid autoantibodies and use of OCs. Women aged 60-65 years receiving HRT now or previously had a lower prevalence of Tg-Ab (univariate, P = 0.01; multivariate, P = 0.02). No such association was observed between HRT and TPO-Ab. CONCLUSION: In this population study there was no association between previous pregnancy, parity and thyroid antibodies, which argues against the role of microchimerism as a trigger of thyroid autoimmunity. Exogenous oestrogens may reduce aspects of autoimmunity.

Thyroid peroxidase and thyroglobulin auto-antibodies in patients with newly diagnosed overt hypothyroidism.

OBJECTIVES: Thyroid autoimmunity is a major cause for hypothyroidism. We describe thyroid auto-antibodies in patients with various nosological subtypes of hypothyroidism identified in a population study. DESIGN: Population-based follow-up study identifying all new cases of hypothyroidism in an open cohort. METHODS: We established a monitoring system, and identified all new cases with primary overt hypothyroidism (n = 685) in a 4 year period in a well-defined population cohort (2,027,208 person-years of observation). Patients were sub-classified into: spontaneous hypothyroidism, presumably of autoimmune origin (n = 578); non-spontaneous hypothyroidism (associated with medication, delivery, neck-irradiation or subacute thyroiditis, n = 97); and congenital hypothyroidism (n = 10). A total of 186 adult patients (61% of those invited) underwent thyroid ultrasonography and measurements of antibodies against thyroid peroxidase (TPOAb) and thyroglobulin (TgAb). RESULTS: In spontaneously hypothyroid patients: >99% were antibody-positive (TPOAb or TgAb), TPOAb were more often measurable than TgAb (95.9 vs. 80.7%, p < 0.001). A statistically significant but modest correlation was observed between the two antibodies (Pearson's r2 = 0.11, p < 0.001). In a multivariate regression model both TPOAb and TgAb were positively associated with thyroid enlargement (p < 0.001), whereas no association was found with sex, age, iodine deficiency level or serum TSH level. We found no differences in patient characteristics between those who mainly developed TPOAb vs. those who preferentially harboured TgAb. CONCLUSIONS: Autoimmunity played a dominant role in practically all patients classified as spontaneously hypothyroid. Thyroid enlargement was associated with high levels of TPOAb and TgAb. We found no clue to why some spontaneously hypothyroid patients predominantly developed TPOAb whereas others mainly generated TgAb.

Iodine status in the Nordic countries - past and present.

BACKGROUND: Adequate iodine nutrition is dependent on ground water content, seafood, and, as many countries use iodized cow fodder, dairy products. In most countries, salt fortification programs are needed to assure adequate iodine intake. OBJECTIVES: The objectives are threefold: 1) to describe the past and present iodine situation in the Nordic countries, 2) to identify important gaps of knowledge, and 3) to highlight differences among the Nordic countries' iodine biomonitoring and fortification policies. DESIGN: Historical data are compared with the current situation. The Nordic countries' strategies to achieve recommended intake and urine iodine levels and their respective success rates are evaluated. RESULTS: In the past, the iodine situation ranged from excellent in Iceland to widespread goiter and cretinism in large areas of Sweden. The situation was less severe in Norway and Finland. According to a 1960 World Health Organization (WHO) report, there were then no observations of iodine deficiency in Denmark. In Sweden and Finland, the fortification of table salt was introduced 50-75 years ago, and in Norway and Finland, the fortification of cow fodder starting in the 1950s helped improve the population's iodine status due to the high intake of milk. In Denmark, iodine has been added to household salt and salt in bread for the past 15 years. The Nordic countries differ with regard to regulations and degree of governmental involvement. There are indications that pregnant and lactating women, the two most vulnerable groups, are mildly deficient in iodine in several of the Nordic countries. CONCLUSION: The Nordic countries employ different strategies to attain adequate iodine nutrition. The situation is not optimal and is in need of re-evaluation. Iodine researchers, Nordic national food administrations, and Nordic governmental institutions would benefit from collaboration to attain a broader approach and guarantee good iodine health for all.

Iodine deficiency in pregnancy is prevalent in vulnerable groups in Denmark.

INTRODUCTION: Iodine is essential for the production of thyroid hormones. In pregnancy, physiological changes occur that can lead to iodine deficiency and impairment of fetal neurological development. We aimed to assess the iodine intake in pregnant women in Eastern Denmark, compare iodine levels in Eastern and Western Denmark and to identify potentially vulnerable groups. METHODS: This was a cross-sectional cohort study of pregnant Danish women (n = 240). Questionnaires and urine samples were collected at the Ultrasound Clinic, Hvidovre Hospital, Denmark, and urinary iodine concentrations (UIC) (µg/l) were measured. Predictors of iodine supplement use were examined by multivariate logistic regression models. RESULTS: The pregnant women from Eastern Denmark had a median age of 30 years and the median gestational week at which they were included in the study was week 19. The majority took iodine-containing supplements (86%). The median UIC was 118 (interquartile range (IQR): 79-196) µg/l in iodine supplement users and 82 (IQR: 41-122) µg/l in non-users (p < 0.001). Predictors of not using iodine supplement in Eastern and Western Denmark were short maternal education, non-Danish origin and pre-pregnancy obesity. CONCLUSIONS: The iodine status in Danish pregnant women was below WHO recommendations. Iodine supplement non-users are at a particular risk of iodine deficiency. Low maternal education, non-Danish origin and pre-pregnancy obesity are predictors of non-iodine supplement use. An increase in iodine fortification may be recommended to improve the iodine status in pregnant Danish women. FUNDING: none. TRIAL REGISTRATION: not relevant.

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. In the study presented here, 1749 non-pregnant women with no history of thyroid disease were included who participated in the 11-year follow-up examination in the period 2008-2010. Gynecological exposures were reported in a self-administered questionnaire at baseline and follow-up. TSH and TPOAb were measured at baseline and follow-up. Increased TPOAb status during follow-up was defined as a TPOAb below the assay cutoff (<30 kIU/L) at baseline and a TPOAb ≥30 kIU/L at follow-up. Multiple linear regression models were used, adjusted for age, smoking status, and urinary iodine excretion. RESULTS: An inverse association was found between the number of years on HRT and the risk (odds ratio) of increased TPOAb status during follow-up (0.735 [confidence interval 0.558-0.968], p = 0.03). However, this association was not statistically significant when applying the Bonferroni adjusted significance level. The remaining reproductive factors showed no statistically significant association with risk of increased TPOAb during follow-up. Furthermore, parity, abortions, use of OCP, HRT use, age at menarche, and being pre- or postmenopausal were not significantly associated with 11-year TSH change. CONCLUSIONS: No statistically significant association was found between the studied female reproductive measures and 11-year risk of TSH or TPO change. A possible protective role for HRT in the etiology of thyroid autoimmunity, however, deserves further research.

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. METHODS: We examined 2465 adults and a total of 1417 participants with no previous thyroid disease and without Tg-autoantibodies were included in the analyses. Serum Tg was measured by immunoradiometric method. We registered participants with a daily intake of iodine from supplements in addition to IF. RESULTS: Overall, the follow-up period saw no change in median Tg in Copenhagen (9.1/9.1 µg/l, P=0.67) while Tg decreased significantly in Aalborg (11.4/9.0 µg/l, P<0.001). Regional differences were evident before IF (Copenhagen/Aalborg, 9.1/11.4 µg/l, P<0.001), whereas no differences existed after IF (9.1/9.0 µg/l, P=1.00). Living in Aalborg (P<0.001) and not using iodine supplements at baseline (P=0.001) predicted a decrease in Tg whereas baseline thyroid enlargement (P=0.02) and multinodularity (P=0.01) were associated with an individual increase in Tg during follow-up. CONCLUSIONS: After IF we observed a decrease in median Tg in Aalborg and the previously observed regional differences between Aalborg and Copenhagen had levelled out. Likewise, living in Aalborg was a strong predictor of an individual decrease in serum Tg. Thus, even small differences in iodine intake at baseline were very important for the individual response to IF.

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 53.0 y) and age- and region-matched euthyroid controls from the same population (n = 468). MAIN OUTCOME MEASURES: In conditional multivariate logistic regression models, we analyzed the associations between the development of autoimmune hypothyroidism and age at menarche/menopause, years of menstruations, pregnancies, spontaneous and induced abortions, live births, and years on oral contraceptives and postmenopausal hormone replacement therapy, also taking various possible confounders into account. RESULTS: In multivariate regression models with no event as reference, the odds ratios (ORs) for hypothyroidism [95% confidence interval (CI)] after one/two/three or more live births were 1.72 (0.56-5.32)/3.12 (1.14-8.48)/4.51 (1.65-12.3) and 1.02 (0.57-1.81)/2.70 (1.27-5.75) after one/two or more induced abortions. Findings were valid only for women having hypothyroidism diagnosed before the age of 55 years. We found no association between disease development and other reproductive risk factors investigated. CONCLUSIONS: Previous live births and induced abortions were major risk factors for the development of autoimmune overt hypothyroidism in women aged up to 55 years. The increased risk for hypothyroidism after giving birth extends longer than just to the 1-year postpartum period, and numbers of previous pregnancies should be taken into account when evaluating the risk of hypothyroidism in a young women.