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. Therefore, we aimed to examine how the association between incident hyperthyroidism and AF was affected by IF increasing the population iodine intake from moderate‐mild iodine deficiency to low adequacy.
Design, Patients and Measurements
Incident hyperthyroid patients were included at the date of first inpatient or outpatient diagnosis, and AF diagnoses within 3 months before to 6 months after the index date were identified in Danish nationwide registers, 1997–2018. The relative risk (RR) of AF each calendar year (reference: 1997; IF introduced: 2000) was analyzed in Poisson regression models adjusted for age, sex, educational level, geographic region, and comorbidities.
Results
Overall, in 62,201 patients with incident hyperthyroidism 7.9% were diagnosed with AF. There was a minor nonsignificantly increased risk of AF during the first years after IF followed by a gradual decrease to RR 0.76 (0.62–0.94) in 2017. There were no statistically significant differences in the development in the risk of AF by sex, age group, or geographic region.
Conclusions
Results indicate that IF may reduce the risk of concomitant AF in hyperthyroid patients. If these results are confirmed, IF may not only reduce the population incidence of hyperthyroidism but also reduce the burden of morbidity in the remaining hyperthyroid patients.
The Glostrup Population Studies are population-based cohorts undertaken in the south-western part of Greater Copenhagen since 1964. The participants were randomly selected from the adult general ...population. The first cohort was established to assess cardiovascular risk factors and, since, the objectives have been broadened to describe and analyse the health of the general population. The studies are health-examination studies with clinical and biochemical data in addition to data from self-administered questionnaires and, in some studies, interviews. Fasting blood and urine samples were collected and stored in our biobank for further studies. Several of the cohorts were performed according to standardized methods in international consortia, hence data have been pooled with other, both Danish and international, cohorts. To date more than 30,000 individuals, both men and women, aged 15–85 years, have participated in The Glostrup Population Studies and participants have been re-examined up to eight times. The data can be used for disease-specific epidemiology, social epidemiology, genetic epidemiology, ageing, lifestyle and health interventions nested within the cohorts. The Glostrup Population Studies represent a great resource; the possibility of merging the different cohorts enables large datasets, as well as trends over time. Furthermore, the long follow-up in both the national registers and with follow-up examinations is unique. The purpose of this commentary is to inform about The Glostrup Population Studies and to invite collaborations to continue utilizing this great resource to combat current and future challenges within health promotion and disease prevention.
Studies of the effect of vitamin B12 and folate on the risk of asthma and hay fever have shown inconsistent results that may be biased by reverse causation and confounding. We used a Mendelian ...randomization approach to examine a potential causal effect of vitamin B12 and folate on hay fever, asthma, and selected biomarkers of allergy by using 11 vitamin B12-associated single-nucleotide polymorphisms (SNPs) and 2 folate-associated SNPs as unconfounded markers.
We included 162,736 participants from 9 population-based studies including the UK Biobank. Results were combined in instrumental variable and meta-analyses and effects expressed as odds ratios (ORs) or estimates with 95% confidence interval (CI).
Using genetic proxies for B12 and folate, instrumental variable analyses did not show evidence for associations between serum B12 and hay fever: OR = 1.02 (95% CI: 0.98, 1.05), asthma: OR = 0.99 (95% CI: 0.95, 1.04), allergic sensitization: OR = 1.02 (95% CI: 0.74, 1.40), or change in serum IgE: 10.0% (95% CI: -9.6%, 29.6%) per 100 pg/ml B12. Similarly, there was no evidence for association between serum folate and hay fever: OR = 0.74 (95% CI: 0.45, 1.21), asthma: OR = 0.80 (95% CI: 0.43, 1.49), or allergic sensitization: OR = 1.92 (95% CI: 0.11, 33.45), but there was a statistically significant association with change in serum IgE: 2.0% (95% CI: 0.43%, 3.58%) per 0.1 ng/ml serum folate.
Our results did not support the hypothesis that levels of vitamin B12 and folate are causally related to hay fever, asthma, or biomarkers of allergy, but we found evidence of a positive association between serum folate and serum total IgE.
Summary Background Changes in body composition in cancer patients during chemotherapy are associated with treatment related toxicities or mortalities. Thus, it is relevant to identify accessible, ...relatively inexpensive, portable and reliable tools for evaluation of body composition in cancer patients during the course of their treatments. Objective To examine relationships between single cross-sectional thighs magnetic resonance imaging (MRI), skeletal muscle mass (SM) as reference and multi-frequency bioelectrical impedance analysis (BIA) fat free mass (FFM) in patients with colorectal cancer undergoing chemotherapy. Design In an observational, prospective study we examine the relationships between single cross-sectional thighs MRI (T1-weighted (1.5 T) SM compared to FFM BIA (8-electrodes multi-frequency Tanita MC780MA)) and FFM skin-fold thickness (ST) (4-points (Harpenden, Skinfold Caliper)) and SM equation for non-obese persons from Lee et al. 2000 (L2000) (based on age, height, weight, sex and race). FFM and SM (kg) were calculated based on either area (MRI) or weight. Results 18 CRC patients (10 males and 8 females) with mean (SD) age 67 yr (6) were measured at baseline, and 13 were available for follow-up. BIA overestimated FFM kg for all 31 measurements with mean (SD) 18.0 kg (6.0) compared to the MRI. ST overestimated FFM kg with mean 12.4 kg (6.2) and L2000 underestimated SM kg in 18 measurements and overestimated in 13 with a total mean of −4.3 kg (6.8). Conclusions BIA and ST were the best alternatives to MRI as they showed constant and thereby correctable errors. The equation, L2000, carried the smallest average measurement error but it was non-constant.
To investigate possible biochemical abnormalities associated with celiac disease (CD) antibody positivity in a primary health care setting and thereby identify predictors that could potentially ...reduce diagnostic delay and underdiagnosis of CD. This observational cohort study included measurements of CD antibodies in the Copenhagen Primary Care Laboratory (CopLab) database from 2000 to 2015; CD antibody positivity was defined as tissue transglutaminase antibody IgA or IgG ≥ 7 kU/L and/or deamidated gliadin peptide antibody IgG ≥ 10 kU/L. Individuals with a prior diagnosis of CD were excluded. We examined differences between individuals with positive and negative CD antibody tests regarding the results of biochemical tests performed six months before and one month after the date of the CD antibody test. We identified 76,265 measurements of CD antibodies during 2000-2015, and 57,061 individuals met the inclusion criteria (706 antibody-positive and 56,355 antibody-negative). We found lower ferritin, hemoglobin, cobalamin and folic acid levels and higher levels of transferrin, ALAT (alanine transaminase), and alkaline phosphate among individuals with a positive CD antibody test. Furthermore, we illustrated more measurements below the sex-specific reference intervals for hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), ferritin, cobalamin and folic acid among individuals with a positive CD antibody test. This study identified several biochemical abnormalities associated with CD antibody positivity among individuals referred to CD antibody testing. The pattern of abnormalities suggested that micronutrient deficiencies were prevalent among CD antibody-positive individuals, confirming malabsorption as a sign of CD. These findings illustrate the possibility of reducing diagnostic delay and underdiagnosis of CD.
ObjectiveThis study aimed to examine the association of eczema, asthma and hay fever with mental health in a general child population and to assess the influence of parental socioeconomic position on ...these associations.MethodsWe conducted a cross-sectional health survey of children aged 3, 6, 11 and 15 years in the City of Copenhagen, Denmark. Individual questionnaire data on eczema, asthma, and hay fever and mental health problems assessed using the Strengths and Difficulties Questionnaire (SDQ) was linked to register data on demographics and parental socioeconomic position. 9215 (47.9%) children were included in the analyses.ResultsLinear regression analyses showed that children with current eczema symptoms had higher SDQ scores (mean difference, 95% CI) of emotional problems (0.26, 0.12 to 0.39), conduct problems (0.19, 0.09 to 0.29) and hyperactivity problems (0.32, 0.16 to 0.48); children with current asthma symptoms had higher SDQ scores of emotional problems (0.45, 0.32 to 0.58), conduct problems (0.28, 0.18 to 0.38) and hyperactivity problems (0.52, 0.35 to 0.69); and children with current hay fever symptoms had higher SDQ scores of emotional problems (0.57, 0.42 to 0.72), conduct problems (0.22, 0.11 to 0.33), hyperactivity problems (0.44, 0.26 to 0.61) and peer problems (0.14, 0.01 to 0.26), compared with children without current symptoms of the relevant disease. For most associations, parental socioeconomic position did not modify the effect.ConclusionsChildren with eczema, asthma or hay fever had more emotional, conduct and hyperactivity problems, but not peer problems, compared with children without these diseases. Atopic diseases added equally to the burden of mental health problems independent of socioeconomic position.
Objective
The incidence of hypothyroidism is not expected to differ by socioeconomic factors. However, the decision to test and initiate treatment may differ. We aimed to examine whether educational ...level influences the probability of thyroid stimulation hormone (TSH)‐measurement and initiation of levothyroxine treatment.
Design
Citizens in the greater Copenhagen Area during 2001‐2015 were included. Individual‐level data on educational level, diagnoses, GP‐contact, TSH‐measurement and medication were derived from administrative and healthcare registers. The relative risks (RR) between educational levels of annual TSH‐measurement and treatment initiation following a TSH‐measurement were analysed in Poisson regression models with generalized estimation equations.
Results
A TSH‐measurement was performed in 19% of 9,390,052 person years. The probability of TSH‐measurement was higher with short (RR 1.16 95% CI 1.15–1.16) and medium (RR 1.11 95% CI 1.06–1.12) compared with long education.
Treatment was initiated after 0.8% of 2,049,888 TSH‐measurements. For TSH < 5 mIU/L, RR for treatment initiation ranged between 0.47 (95%CI 0.39–0.57) and 0.78 (95%CI 0.67–0.91) for short and medium compared with long education. For TSH 5–10 mIU/L, there was no statistically significant difference. For TSH > 10 mIU/L, RR was 1.07 (95% CI 1.02–1.12) for short and 1.08 (95% CI 1.03–1.13) for medium compared with long education.
Conclusion
The probability of TSH‐measurement was higher with shorter education, and the probability of treatment initiation with TSH > 10 mIU/L was marginally higher with short‐medium education compared with long education. However, the probability of treatment initiation with TSH < 5 mIU/L, that is treatment incongruous with guidelines, was substantially higher in persons with long education.
Long-term iodine exposure may influence the frequency of thyroid disease treatments through fluctuations in thyroid diseases. Yet, the long-term fluctuations in thyroid disease treatments upon iodine ...fortification (IF) are not fully known. We aimed to examine the development in thyroid disease treatments in Denmark before and following the implementation of IF in 2000.
Nationwide data on antithyroid medication, thyroid hormone therapy, thyroid surgery, and radioiodine treatment were obtained from Danish registries. Negative binominal regression was applied to analyze annual changes in treatment rates adjusted for region of residence, sex, and age.
Incidence of antithyroid medication transiently increased but fell and reached steady state from 2010 at an incidence rate ratio (RR) of 0.72 (95% confidence interval CI 0.67-0.77) compared to year 2000. Thyroid hormone therapy increased and reached steady state in 2010 at an incidence RR of 1.75 (95% CI 1.62-1.89) compared to year 2000. Thyroid surgery was constant except for higher rates in 2014-2015, and radioiodine treatment fluctuated with no apparent pattern.
Ten years after IF, a steady state was observed for incident antithyroid medication below the level at IF, and thyroid hormone therapy above the level at IF. Only small changes were observed in thyroid surgery and radioiodine treatment. In the same period, changes in diagnostic and treatment practices and lifestyle factors are likely to have occurred and should be considered when evaluating the effects of IF on treatment of thyroid diseases.
Purpose
Thyroid dysfunction may affect the risk of cardiovascular disease and mortality through effects on myocardial and vascular tissue and metabolism. Levels of thyroid stimulating hormone (TSH) ...indicates thyroid function. We aimed to assess the association between TSH-levels and incident ischemic heart disease (IHD), incident stroke, and all-cause mortality.
Methods
We included 13,865 participants (18–71 years, 51.6% women) from five cohort studies conducted during 1974–2008 were included. TSH was measured at the baseline examination and classified as <0.4; 0.4–2.5 (ref.); 2.5–5.0; 5.0–10, or >10 mU/l. Incident IHD, incident stroke, and all-cause mortality were identified in registries until ultimo 2013. Data were analysed by multivariate Cox regression with age as underlying time axis. Results from the individual cohorts were pooled by random-effects meta-analysis.
Results
The crude incidence rate was for IHD 7.8 cases/1000 person years (PY); stroke 5.4 cases/1000 PY; and all-cause mortality 11.3 deaths/1000 PY (mean follow-up: 14 years). Analyses showed no statistically significant associations between TSH-levels and incident IHD or incident stroke in the partly or fully adjusted models. There was a statistically significant association between TSH of 2.5–5 mU/l and all-cause mortality (hazard ratio 1.145 (95% CI 1.004–1.306) compared with TSH of 0.4–2.5 mU/l in the fully adjusted model.
Conclusion
The results do not provide evidence of a harmful effect of decreased or increased TSH on IHD or stroke in the general population. However, there is some indication of an elevated risk for all-cause mortality with TSH 2.5–5 mU/l compared with 0.4–2.5 mU/l.
Thyroid hormones are critical for neural development, and during the first trimester of pregnancy the fetus relies fully on maternal thyroid hormone production.
To investigate the associations ...between maternal thyroid hormone levels in the first trimester with the child's school performance, risk of attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD).
From the Copenhagen Primary Care Laboratory Pregnancy Database information on first trimester TSH and fT4 measurements in mothers of children born in 2000-2014 were linked with information on the child's standardized test scores in school, ADHD (patient record diagnoses and medication) and ASD (patient record diagnoses) until end of 2018. Associations of TSH and fT4 with the outcomes were individually assessed by linear mixed models and Cox regression models. The analyses were stratified by preexisting maternal thyroid disorders.
TSH measurements were available for 17,909 mother-child dyads. Among those with children born in 2000-2009, 6,126 had a standardized school test score and were analyzed for the association between maternal thyroid hormone levels and child's school performance, and no support for an association was found. The association between thyroid hormone levels and child's risk of ADHD and ASD were analyzed for the 17,909 dyads and with no support for an association between thyroid hormone levels and these neurodevelopmental disorders. Stratification by preexisting maternal thyroid disorders did not affect the results.
We found no evidence for associations between first trimester maternal thyroid hormone levels and child's school performance, or risk of ADHD or ASD.
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