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The Lancet. Diabetes & Endocrinology Oct 2023Reference intervals of thyroid-stimulating hormone (TSH) and free thyroxine (FT) are statistically defined by the 2·5-97·5th percentiles, without accounting for... (Meta-Analysis)
Meta-Analysis
The optimal healthy ranges of thyroid function defined by the risk of cardiovascular disease and mortality: systematic review and individual participant data meta-analysis.
BACKGROUND
Reference intervals of thyroid-stimulating hormone (TSH) and free thyroxine (FT) are statistically defined by the 2·5-97·5th percentiles, without accounting for potential risk of clinical outcomes. We aimed to define the optimal healthy ranges of TSH and FT based on the risk of cardiovascular disease and mortality.
METHODS
This systematic review and individual participant data (IPD) meta-analysis identified eligible prospective cohorts through the Thyroid Studies Collaboration, supplemented with a systematic search via Embase, MEDLINE (Ovid), Web of science, the Cochrane Central Register of Controlled Trials, and Google Scholar from Jan 1, 2011, to Feb 12, 2017 with an updated search to Oct 13, 2022 (cohorts found in the second search were not included in the IPD). We included cohorts that collected TSH or FT, and cardiovascular outcomes or mortality for adults (aged ≥18 years). We excluded cohorts that included solely pregnant women, individuals with overt thyroid diseases, and individuals with cardiovascular disease. We contacted the study investigators of eligible cohorts to provide IPD on demographics, TSH, FT, thyroid peroxidase antibodies, history of cardiovascular disease and risk factors, medication use, cardiovascular disease events, cardiovascular disease mortality, and all-cause mortality. The primary outcome was a composite outcome including cardiovascular disease events (coronary heart disease, stroke, and heart failure) and all-cause mortality. Secondary outcomes were the separate assessment of cardiovascular disease events, all-cause mortality, and cardiovascular disease mortality. We performed one-step (cohort-stratified Cox models) and two-step (random-effects models) meta-analyses adjusting for age, sex, smoking, systolic blood pressure, diabetes, and total cholesterol. The study was registered with PROSPERO, CRD42017057576.
FINDINGS
We identified 3935 studies, of which 53 cohorts fulfilled the inclusion criteria and 26 cohorts agreed to participate. We included IPD on 134 346 participants with a median age of 59 years (range 18-106) at baseline. There was a J-shaped association of FT with the composite outcome and secondary outcomes, with the 20th (median 13·5 pmol/L [IQR 11·2-13·9]) to 40th percentiles (median 14·8 pmol/L [12·3-15·0]) conveying the lowest risk. Compared with the 20-40th percentiles, the age-adjusted and sex-adjusted hazard ratio (HR) for FT in the 80-100th percentiles was 1·20 (95% CI 1·11-1·31) for the composite outcome, 1·34 (1·20-1·49) for all-cause mortality, 1·57 (1·31-1·89) for cardiovascular disease mortality, and 1·22 (1·11-1·33) for cardiovascular disease events. In individuals aged 70 years and older, the 10-year absolute risk of composite outcome increased over 5% for women with FT greater than the 85th percentile (median 17·6 pmol/L [IQR 15·0-18·3]), and men with FT greater than the 75th percentile (16·7 pmol/L [14·0-17·4]). Non-linear associations were identified for TSH, with the 60th (median 1·90 mIU/L [IQR 1·68-2·25]) to 80th percentiles (2·90 mIU/L [2·41-3·32]) associated with the lowest risk of cardiovascular disease and mortality. Compared with the 60-80th percentiles, the age-adjusted and sex-adjusted HR of TSH in the 0-20th percentiles was 1·07 (95% CI 1·02-1·12) for the composite outcome, 1·09 (1·05-1·14) for all-cause mortality, and 1·07 (0·99-1·16) for cardiovascular disease mortality.
INTERPRETATION
There was a J-shaped association of FT with cardiovascular disease and mortality. Low concentrations of TSH were associated with a higher risk of all-cause mortality and cardiovascular disease mortality. The 20-40th percentiles of FT and the 60-80th percentiles of TSH could represent the optimal healthy ranges of thyroid function based on the risk of cardiovascular disease and mortality, with more than 5% increase of 10-year composite risk identified for FT greater than the 85th percentile in women and men older than 70 years. We propose a feasible approach to establish the optimal healthy ranges of thyroid function, allowing for better identification of individuals with a higher risk of thyroid-related outcomes.
FUNDING
None.
Topics: Male; Adult; Humans; Female; Pregnancy; Aged; Aged, 80 and over; Adolescent; Young Adult; Middle Aged; Thyroid Gland; Thyroid Function Tests; Thyroxine; Prospective Studies; Cardiovascular Diseases; Thyrotropin
PubMed: 37696273
DOI: 10.1016/S2213-8587(23)00227-9 -
The Journal of International Medical... Dec 2021To perform a meta-analysis of randomized controlled trials to evaluate the efficacy of vitamin D supplementation on thyroid autoimmunity markers in Hashimoto's... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To perform a meta-analysis of randomized controlled trials to evaluate the efficacy of vitamin D supplementation on thyroid autoimmunity markers in Hashimoto's thyroiditis (HT).
METHODS
This meta-analysis included randomized controlled clinical trials identified by a systematic search of electronic databases (PubMed®, MEDLINE®, EMBASE, The Cochrane Library, China National Knowledge Infrastructure) from inception to August 2020. All studies included patients with HT that received vitamin D supplementation irrespective of the doses administered or the duration of treatment. The primary and secondary outcome measures were thyroid peroxidase antibody (TPOAb) and/or thyroglobulin antibody (TGAb) titres.
RESULTS
Eight studies ( = 652) were included. There was significant heterogeneity between the studies. Using a random-effect model, vitamin D supplementation reduced TPOAb titre (standardized mean difference [SMD]: -1.11; 95% confidence interval [CI]: 1-1.92, -0.29) and TGAb titre (SMD: -1.12; 95% CI: -1.96, -0.28). A subgroup analysis demonstrated that vitamin D supplementation for >3 months resulted in a decrease in TPOAb titre (SMD: -1.66, 95% CI: -2.91, -0.41) but treatment ≤3 months was ineffective. Treatment with vitamin D decreased TPOAb titre (SMD: -1.48; 95% CI: -2.53, -0.42) whereas vitamin D did not.
CONCLUSION
These data suggest that vitamin D reduces autoantibody titre in patients with HT.
Topics: Autoimmunity; Dietary Supplements; Hashimoto Disease; Humans; Vitamin D
PubMed: 34871506
DOI: 10.1177/03000605211060675 -
Autoimmunity Reviews Jan 2021The testing of anti-neutrophil cytoplasmic antibodies (ANCA) takes an important place in the diagnostic workup to ANCA-associated vasculitis (AAV). Nowadays, it is... (Meta-Analysis)
Meta-Analysis
The testing of anti-neutrophil cytoplasmic antibodies (ANCA) takes an important place in the diagnostic workup to ANCA-associated vasculitis (AAV). Nowadays, it is recommended to screen for the presence of PR3 and MPO specific antibodies first using immunoassay, without the need for ANCA measurement by indirect immunofluorescence (IIF). A literature search was performed to assess the diagnostic test value of ANCA IIF and PR3- and MPO-antibody immunoassay to diagnose AAV. This meta-analysis shows that the c-ANCA testing by IIF has a pooled sensitivity of 75.2% and a pooled specificity of 98.4%. For PR3-antibody immunoassay, the pooled sensitivity depended on the immunoassay method used, and ranged from 79.8% to 86.6%, whereas the pooled specificity ranged from 96.8% to 98.3%. For both p-ANCA IIF and MPO-antibody immunoassay (all methods) sensitivity varied considerably showing pooled values of respectively 46.3% and 58.1%, whereas respective pooled specificity was 91.4% and 95.6%. These findings support the 2017 international consensus that primary anti-PR3 and anti-MPO screening by immunoassay, based on superior immunoassay sensitivity without the need for IIF ANCA testing, improves the diagnostic workup of AAV.
Topics: Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis; Antibodies, Antineutrophil Cytoplasmic; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique, Indirect; Humans; Immunoassay; Myeloblastin; Peroxidase
PubMed: 33197574
DOI: 10.1016/j.autrev.2020.102716 -
Thyroid : Official Journal of the... Mar 2024Hashimoto thyroiditis (HT) is the most common cause of hypothyroidism in iodine-sufficient areas. Selenium is an essential trace element required for thyroid hormone... (Meta-Analysis)
Meta-Analysis
Hashimoto thyroiditis (HT) is the most common cause of hypothyroidism in iodine-sufficient areas. Selenium is an essential trace element required for thyroid hormone synthesis and exerts antioxidant effects. Therefore, it may be of relevance in the management of HT. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of selenium supplementation on thyroid function (thyrotropin [TSH], free and total thyroxine [fT4, T4], free and total triiodothyronine [fT3, T3]), thyroid antibodies (thyroid peroxidase antibodies [TPOAb], thyroglobulin antibodies [TGAb], thyrotropin receptor antibody [TRAb]), ultrasound findings (echogenicity, thyroid volume), immune markers, patient-reported outcomes, and adverse events in HT. The study protocol was registered on PROSPERO (CRD42022308377). We systematically searched MEDLINE, Embase, CINHAL, Web of Science, Google Scholar, and the Cochrane CENTRAL Register of Trials from inception to January 2023 and searched citations of eligible studies. Two independent authors reviewed and coded the identified literature. The primary outcome was TSH in patients without thyroid hormone replacement therapy (THRT); the others were considered secondary outcomes. We synthesized the results as standardized mean differences (SMD) or odds ratio (OR), assessed risk of bias using the Cochrane RoB 2 tool, and rated the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. We screened 687 records and included 35 unique studies. Our meta-analysis found that selenium supplementation decreased TSH in patients without THRT (SMD -0.21 [confidence interval, CI -0.43 to -0.02]; 7 cohorts, 869 participants; = 0%). In addition, TPOAb (SMD -0.96 [CI -1.36 to -0.56]; 29 cohorts; 2358 participants; = 90%) and malondialdehyde (MDA; SMD -1.16 [CI -2.29 to -0.02]; 3 cohorts; 248 participants; = 85%) decreased in patients with and without THRT. Adverse effects were comparable between the intervention and control groups (OR 0.89 [CI 0.46 to 1.75]; 16 cohorts; 1339 participants; = 0%). No significant changes were observed in fT4, T4, fT3, T3, TGAb, thyroid volume, interleukin (IL)-2, and IL-10. Overall, certainty of evidence was moderate. In people with HT without THRT, selenium was effective and safe in lowering TSH, TPOAb, and MDA levels. Indications for lowering TPOAb were found independent of THRT.
Topics: Humans; Autoantibodies; Dietary Supplements; Hashimoto Disease; Randomized Controlled Trials as Topic; Selenium; Thyrotropin
PubMed: 38243784
DOI: 10.1089/thy.2023.0556 -
International Journal of Molecular... Nov 2022Autoimmune thyroid diseases (AITDs) are chronic autoimmune disorders that cause impaired immunoregulation, leading to specific immune responses against thyroid antigens.... (Meta-Analysis)
Meta-Analysis Review
Autoimmune thyroid diseases (AITDs) are chronic autoimmune disorders that cause impaired immunoregulation, leading to specific immune responses against thyroid antigens. Graves' disease (GD) and Hashimoto's thyroiditis (HT) are the major forms of AITDs. Increasing evidence suggests a possible role of microbiota alterations in the pathogenesis and progression of AITDs. This systematic review was designed to address the following question: "Is microbiota altered in patients with AITDs?" After screening the selected studies using the inclusion and exclusion criteria, 16 studies were included in this review (in accordance with PRISMA statement guidelines). A meta-analysis revealed that patients with HT showed significantly higher values of diversity indices (except for the Simpson index) and that patients with GD showed significant tendencies toward lower values of all assessed indices compared with healthy subjects. However, the latter demonstrated a higher relative abundance of and at the phylum level and thus and at the genus level, respectively. Thyroid peroxidase antibodies showed the most significant positive and negative correlations between bacterial levels and thyroid functional parameters. In conclusion, significant alterations in the diversity and composition of the intestinal microbiota were observed in both GD and HT patients.
Topics: Humans; Hashimoto Disease; Graves Disease; Autoimmune Diseases; Microbiota
PubMed: 36362236
DOI: 10.3390/ijms232113450 -
Animals : An Open Access Journal From... Feb 2021The intent of this review is to summarize the knowledge about selenium and its function in a dog's body. For this purpose, systematic literature search was conducted.... (Review)
Review
The intent of this review is to summarize the knowledge about selenium and its function in a dog's body. For this purpose, systematic literature search was conducted. For mammals, including dogs, a balanced diet and sufficient intake of selenium are important for correct function of metabolism. As for selenium poisoning, there are no naturally occurring cases known. Nowadays, we do not encounter clinical signs of its deficiency either, but it can be subclinical. For now, the most reliable method of assessing selenium status of a dog is measuring serum or plasma levels. Levels in full blood can be measured too, but there are no reference values. The use of glutathione peroxidase as an indirect assay is questionable in canines. Commercial dog food manufactures follow recommendations for minimal and maximal selenium levels and so dogs fed commercial diets should have balanced intake of selenium. For dogs fed home-made diets, complex data are missing. However, subclinical deficiency seems to affect, for example, male fertility or recovery from parasitical diseases. Very interesting is the role of selenium in prevention and treatment of cancer.
PubMed: 33562028
DOI: 10.3390/ani11020418 -
The Lancet. Diabetes & Endocrinology Jun 2020Adequate transplacental passage of maternal thyroid hormone is important for normal fetal growth and development. Maternal overt hypothyroidism and hyperthyroidism are... (Meta-Analysis)
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 [FT]) and 929 (2·2%) had isolated hypothyroxinaemia (decreased FT 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 (p=0·10). Each 1 SD increase in FT 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 FT (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).
Topics: Birth Weight; Female; Gestational Age; Humans; Hypothyroidism; Infant, Low Birth Weight; Infant, Newborn; Pregnancy; Pregnancy Complications; Thyroid Function Tests; Thyroid Gland
PubMed: 32445737
DOI: 10.1016/S2213-8587(20)30061-9 -
Neuropsychiatric Disease and Treatment 2021The term myxedema psychosis (MP) was introduced to describe the occurrence of psychotic symptoms in patients with untreated hypothyroidism, but the optimal assessment... (Review)
Review
BACKGROUND AND OBJECTIVE
The term myxedema psychosis (MP) was introduced to describe the occurrence of psychotic symptoms in patients with untreated hypothyroidism, but the optimal assessment and treatment of this condition are unclear. We aimed to synthesize data from the literature to characterize the clinical presentation and management of MP.
METHODS
We performed a systematic review according to the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines in PubMed (Medline), Embase, Google Scholar, and Cochrane databases, including observational studies, case series, and case reports published from 1/1/1980 to 31/12/2019 in the English language. Descriptive statistics along with univariate and multivariate analysis were used for data synthesis.
RESULTS
Out of 1583 articles screened, 71 case reports met our inclusion criteria providing data on 75 MP cases. The median age at diagnosis was 42 years [32-56]. About 53% had no prior hypothyroidism diagnosis. Delusions occurred in 91%, with a predominance of persecutory ideas (84%), while hallucinations occurred in 78%. Physical symptoms and signs of hypothyroidism were absent in 37% and 26%, respectively. If symptoms occurred, nonspecific fatigue was seen most frequently (63%). The median thyroid-stimulating hormone value was 93 mIU/L [60-139]. Thyroid peroxidase antibodies were found positive in 75% (23/33) of reported cases. Creatinine kinase was reported abnormal in seven cases. Cranial imaging (CT or MRI) and electroencephalogram were normal in 89%, 75%, and 73% of the cases reported. The majority of patients were treated orally with thyroxine in combination with short-term antipsychotics. More than 90% of them showed complete recovery. Univariate analysis revealed a trend towards a shorter duration of psychosis with IV thyroid hormone therapy (= 0.0502), but the effect was not consistent in a multivariate analysis.
CONCLUSION
While we identified a substantial lack of published research on MP, our pooled analysis of case observations suggests that the condition presents a broad spectrum of psychiatric and physical symptoms lending support to the value of screening for thyroid dysfunction in patients with first-ever psychosis.
PROSPERO REGISTRATION NUMBER
CRD42020160310.
PubMed: 34447249
DOI: 10.2147/NDT.S318651 -
Public Health Nutrition Jun 2014Se is an antioxidant micronutrient and has been studied for its potential role in CVD prevention. The purpose of the present study was to conduct a systematic review of... (Review)
Review
OBJECTIVE
Se is an antioxidant micronutrient and has been studied for its potential role in CVD prevention. The purpose of the present study was to conduct a systematic review of the literature on the relationship between Se and hypertension.
DESIGN
We conducted a systematic literature search in PubMed and OVID of studies on Se levels and hypertension or blood pressure published in English up to June 2011. Articles meeting inclusion criteria were reviewed and the following information was gathered from each publication: study setting, participant demographics, exclusion criteria, intervention if applicable, medium of Se measure, mean level of Se, outcome definition, relationship between Se and the outcome variable, significance of this relationship, and covariates. In studies that also reported glutathione peroxidase levels, we extracted results on the relationship between glutathione peroxidase and hypertension.
RESULTS
Twenty-five articles were included. Approximately half of the studies reported no significant relationship between Se and hypertension. Of the remaining studies, about half found that higher Se levels were associated with lower blood pressure and the other half found the opposite relationship. The studies varied greatly in terms of study population, study design and Se levels measured in participants.
CONCLUSIONS
Based on the present systematic review, there is no conclusive evidence supporting an association between Se and hypertension. Randomized controlled trials and prospective studies with sufficient sample size in populations with different Se levels are needed to fully investigate the relationship between Se and hypertension.
Topics: Blood Pressure; Humans; Hypertension; Nutritional Status; Selenium
PubMed: 23590757
DOI: 10.1017/S1368980013000992 -
Journal of Affective Disorders Jul 2016While thyroid autoantibodies have been linked to depression in general population samples, it is unclear if the immunological milieu of pregnancy alters this... (Review)
Review
BACKGROUND
While thyroid autoantibodies have been linked to depression in general population samples, it is unclear if the immunological milieu of pregnancy alters this association. As a result, we systematically reviewed the literature to determine if abnormal levels of autoantibodies that target thyroperoxidase (TPO-AB) during the perinatal period are associated with an increased risk of antenatal and postnatal depression.
METHODS
MEDLINE, EMBASE, PsycINFO, and CINAHL databases were searched through February 2016. Primary studies that examined TPO-AB titers during pregnancy or the postpartum period, and antenatal or postnatal depression were eligible. The quality of each study was assessed using the Newcastle-Ottawa Scale.
RESULTS
Among the eleven articles selected for synthesis, three of these examined associations between TPO-AB and depression both during pregnancy and in the postpartum period. Three of five studies reported statistically significant associations between elevated TPO-AB titers (TPO-AB+) and concurrent depression at 12-25 weeks gestation. Four of five studies found significant associations between TPO-AB+ status at 12-25 weeks gestation and depression in the postpartum period. Two of four studies found links between postpartum TPO-AB and depression concurrently in the puerperium.
LIMITATIONS
Lack of adjustment for confounding variables limits causal inference and conclusions about the predictive power of TPO-AB.
CONCLUSIONS
Studies suggest that TPO-AB+ in early to mid-pregnancy is associated with concurrent depression and may be predictive of depression in the postpartum period. Future studies with improved methodology are required to better understand the full pathophysiological implications and predictive utility of TPO-AB in perinatal depression.
Topics: Autoantibodies; Autoantigens; Depression; Depression, Postpartum; Female; Humans; Iodide Peroxidase; Iron-Binding Proteins; Pregnancy; Risk Factors
PubMed: 27011366
DOI: 10.1016/j.jad.2016.03.021