Untreated Subclinical Hypothyroidism Research Articles

Subclinical hypothyroidism and type 2 diabetes mellitus: An update

The relationship between subclinical hypothyroidism (SCH) and type 2 diabetes mellitus (DM) is complex and controversial. Many epidemiological studies have reported a positive association; however, few have reported none. In animal models and humans, evidences suggest that hypothyroidism induces insulin resistance, beta cell dysfunction, and increased hepatic glucose production. Untreated SCH can increase the risk of diabetic complications. Beneficial effect of treatment of SCH in patients with diabetic nephropathy (DN) and retinopathy has been seen. Treatment of SCH in patients with DM should be individualized. Treatment of SCH is justified in the patients with thyroid-stimulating hormone (TSH) <10 and DN, diabetic retinopathy and patients positive for antithyroid peroxidase antibody. An algorithm for the treatment of SCH in patients with DM is also provided.

Impact of thyroid hormone treatment on maternal pregnancy outcomes in women with subclinical hypothyroidism without TPOAb: a retrospective cross-sectional study

BackgroundEvidence on the impact of thyroid hormone treatment (LT4) on maternal pregnancy outcomes in women with subclinical hypothyroidism (SCH) without thyroid peroxidase antibodies (TPOAb) positivity is scarce.MethodsSingle centre, cross-sectional study in 1460 women screened for TSH, free T4 and TPOAb at median 13 (11–17) weeks of gestation during the period 2013–2014. Exclusion criteria were twin- and assisted reproduction pregnancies, TPO positivity, overt thyroid dysfunction, and treatment with LT4 before screening. The impact of LT4 on maternal pregnancy outcomes was investigated in a group of 53 women with SCH (TSH > 3.74 mIU/L) in which LT4 was initiated at median 13 (10–22) weeks (treated group). The control group included 18 women with SCH (TSH > 3.74 mIU/L). The prevalence of pregnancy complications in these two groups was compared with that in a euthyroid reference (REF) group of 1389 women (TSH ≤ 3.74 mIU/L).ResultsThe prevalence of pre-eclampsia and gestational diabetes (GDM) was higher in the control group vs the REF group (16.7% vs 5.0% and 27.8% vs 18.9%; p = 0.017 and p = 0.016, respectively), but comparable in the treated group vs the REF group (7.6% vs 5.0% and 22.6% vs 18.9%; p = 0.918 and 0.676, respectively). The prevalence of iron-deficiency anaemia was lower in the treated vs the REF group (17.0% vs 32.5%; p = 0.017).ConclusionPregnant women with untreated SCH and without TPOAb positivity had a higher prevalence of pre-eclampsia and GDM compared with euthyroid women, while this was not the case in women with treated SCH, even when it was initiated after the first trimester.

The influence of nutrition and exercise on untreated subclinical hypothyroidism: A systematic review

Problems: Hypothyroidism is associated with increased cardiovascular events and a reduced quality of life. The goal of this systematic review is to identify additive treatment strategies besides hormone replacement through diet and exercise intervention and to point out research gaps. Methods: A comprehensive literature search was conducted in four databases (PubMed, Scopus, Science direct and SportDiscus) using defined MeSH words by two independent researchers. Literature from year 1990 onwards was considered. Results: To investigate the effects of diet and exercise on thyroid function, three randomized controlled trials and one comparative study with a total of 356 subjects (nutrition) and four randomized controlled trials with a total of 189 subjects (exercise) are identified. The nutrition-related studies show that nutritional interventions can reduce perceived symptoms in subclinical hypothyroidism. An effect on thyroid hormone serum levels has been demonstrated by an intake of selenium and phytoestrogens. Exercise-related studies show improvement in quality of life and symptoms through exercise in subclinical hypothyroidism. Changes in thyroid hormone serum levels could not be shown. Discussion: Due to the heterogeneous parameters recorded in the included studies, no clear conclusion can be drawn. Nevertheless, first findings show that nutrition and exercise have an effect on the symptoms of hypothyroidism. Both measures can reduce the development of comorbidities in subclinical hypothyroidism and improve quality of life. Studies combining both dietary intervention and exercise have not yet been conducted. Key Words: Endocrine disorders, Thyroid Hormones, Diet, Physical Activity, Quality of Life

Growth assessment in down syndrome after cardiac surgery

ObjectiveTo assess the effect of cardiac surgery on growth catch-up of Down syndrome (DS) children with failure to thrive (FTT) and congenital heart disease (CHD) and investigate other causes of FTT in DS children.MethodWe conducted a retrospective observational study in tertiary cardiac center from 2015 to 2018. We included all cases of DS diagnosed with CHD and FTT who completed a 1-year follow-up after cardiac surgery. We divided the cases into two groups; “normalize group” includes children who normalized their growth parameters and “underweight group” includes those who remained in FTT category during the follow-up period. We compared both groups for multiple risk factors.ResultMost of DS had FTT upon surgery. Fifty percent of cases completed 1-year follow-up including 29 (60%) in the normalized group and 19 (40%) in underweight group. Within 6 months post-surgery, the normalized group though did not reach yet normalization of growth parameters, demonstrated statically significant improvement in weight for age, weight Z-score in compared to underweight group.Within 12 months post-surgery, the normalized group achieved normalization of growth parameters and continue to show more statistically significant differences in growth parameters.Both groups had comparable post-operation course. Univariate analysis of possible peri-operative risk factors showed no difference between both groups except for presence of untreated subclinical hypothyroidism in 58% of the underweight group versus 17% in control group (p = 0.005).ConclusionFTT in DS patient is multifactorial which needs thorough investigation and work up by multidisciplinary team. Cardiac surgery may not guarantee the improvement of growth parameters.

The impact of the management strategies for patients with subclinical hypothyroidism on long-term clinical outcomes: An umbrella review.

This umbrella review summarises and compares synthesised evidence on the impact of subclinical hypothyroidism and its management on long-term clinical outcomes. We conducted comprehensive searches on MEDLINE, EMBASE, Scopus, Web of Science, Cochrane Database of Systematic Reviews, JBI Evidence Synthesis, the PROSPERO register, Epistemonikos Database and PDQ Evidence from inception to February and July 2021 using keywords on subclinical hypothyroidism, treatment with levothyroxine, monitoring and primary outcomes (all-cause mortality, cardiovascular events, stroke, frailty fractures and quality of life). Only systematic reviews and meta-analyses on adult patient populations were considered. Study selection, data extraction and quality appraisal using AMSTAR-2 were done independently by two reviewers and discrepancies were resolved through discussion. Overlap across the selected reviews was also assessed, followed by a narrative synthesis of findings. A total of 763 studies were identified from literature searches; 20 reviews met inclusion criteria. Methodological quality ratings were high (n = 8), moderate (n = 7), and low (n = 5), but no reviews were excluded on this basis. Though there was slight overlap across all reviews, some pairwise comparisons had high corrected covered area scores. Compared to euthyroidism, untreated subclinical hypothyroidism was associated with a higher risk of cardiovascular events or death if Thyroid Stimulating Hormone was above 10mIU/L at baseline. Treatment was associated with a lower risk of death from all causes for patients younger than 70 years and possibly better cognitive and quality of life scores than untreated individuals. Evidence on the risk of strokes and fractures was inconclusive. In the long term, treatment of subclinical hypothyroidism may be beneficial for some patient groups. However, the findings of this review are negatively impacted by the relative sparseness and poor quality of available evidence. Additional large and adequately powered studies are needed to investigate this topic further. PROSPERO (CRD42021235172).

The Influence of Treated and Untreated Subclinical Hypothyroidism on Metabolic Profile in Women with Polycystic Ovary Syndrome.

Background Polycystic ovary syndrome (PCOS) and hypothyroidism are the most common endocrinological disorders among women of reproductive age. Since hypothyroidism occurs more frequently in PCOS patients, it is vital to explain its clinical impact. Aim To evaluate the impact of subclinical hypothyroidism (SCH) and its treatment on the metabolic profile of patients with PCOS. Methods 190 women with PCOS phenotype A were enrolled in the case-control study. They were divided into three groups: 38 women with PCOS and subclinical hypothyroidism, 76 women with PCOS and SCH under thyroid replacement therapy, and 76 women with PCOS and normal thyroid function (control group). Serum lipids, fasting glucose, and insulin, as well as oral glucose tolerance tests were performed. Results In the analyzed parameters, there were no statistic differences between the groups in relation to thyroid function. BMI turned out to be the main factor dividing the patients in terms of serum lipids, fasting glucose, fasting insulin, and oral glucose tolerance test. TSH was associated with total cholesterol and LDL cholesterol levels, whereas BMI has a dominant impact on HDL cholesterol, triglycerides, glucose, and insulin resistance. Conclusions SCH is associated with mild lipid serum alterations in women with PCOS, but it is BMI to have a dominant impact on glucose and insulin. It seems that treatment of SCH in PCOS does not significantly alter lipid and glucose metabolism.

Subclinical Hypothyroidism in Children: A Review

Subclinical hypothyroidism is defined as serum levels of TSH above the upper limit of the reference range in the presence of normal concentrations of total T4 or free T4. This biochemical profile might be an indication of mild hypothyroidism, with a potential increased risk of metabolic abnormalities and cardiovascular disease among adults. Whether subclinical hypothyroidism results in adverse health outcomes among children is a matter of debate and so management of this condition remains challenging. Mild forms of untreated subclinical hypothyroidism do not seem to be associated with impairments in growth, bone health or neurocognitive outcome. However, ongoing scientific investigations have highlighted the presence of subtle proatherogenic abnormalities among children with modest elevations in their TSH levels. Although current findings are insufficient to recommend levothyroxine treatment for all children with mild asymptomatic forms of subclinical hypothyroidism, they highlight the potential need for assessment of cardiovascular risk among children with this condition. Increased understanding of the early metabolic risk factors associated with subclinical hypothyroidism in childhood will help to improve the management of affected individuals.
 DS (Child) H J 2020; 36(2): 146-151

PTH-Independent Hypercalcemia in Undiagnosed Adrenal Insufficiency

In contrast to PTH-dependent hypercalcemia, the differential diagnosis of PTH-independent hypercalcemia is extensive. Thorough history and physical examination can help direct the clinician in the right direction and avoid extensive and unnecessary work up.A 27-year-old-female with a medical history significant only for untreated subclinical hypothyroidism was admitted to the hospital for hypercalcemia and acute kidney injury after presenting with dizziness, nausea, vomiting, dyspnea, and multiple syncopal episodes prior to admission. Serum calcium on presentation was elevated to 15.9 (8.5–10.2 mg/dL) with an intact parathyroid hormone level of 3.6 (8.5–75 pg/mL). On initial presentation, she was hypotensive, tachycardic, and was noted to be underweight with a body mass index of 17 kg/m2. The patient’s skin was diffusely hyperpigmented, with increased pigmentation in the creases of her hands and on the sides of her fingers. Further lab evaluation was remarkable for hyponatremia and hyperkalemia as well as an undetectable 8 AM cortisol of <1.0 (7–25 µg/dL), adrenocorticotropic hormone (ACTH) level significantly elevated to >1,250 (6–58 pg/mL), aldosterone <4 (<21 ng/dL), and plasma renin activity elevated to 18 (<0.6–3 ng/mL/h). Antibodies to 21-alpha hydroxylase were positive, confirming a diagnosis of Addison’s disease. Prior to the workup confirming an elevated ACTH and low cortisol levels, the patient was treated with aggressive intravenous fluid repletion and calcitonin with overnight improvement in calcium to 11.4 mg/dL. After the diagnosis of primary adrenal insufficiency was confirmed, she was treated with stress doses of intravenous hydrocortisone then gradually tapered to physiologic doses of oral hydrocortisone and fludrocortisone with resolution of her hypercalcemia by the fourth day of hospitalization.Adrenal insufficiency is a known but uncommon cause of PTH-independent hypercalcemia, but the exact mechanism is unknown. Hypercalcemia is thought to result from a combination of a hypovolemic state seen in adrenal insufficiency which leads to decreased urinary calcium excretion as well as increased bone resorption, which may result from increased serum sclerostin concentrations.Adrenal insufficiency should be considered in the differential of PTH-independent hypercalcemia. This case highlights the improvement in hypercalcemia that is seen with correction of glucocorticoid deficiency, and supports delaying additional work up for other PTH-independent causes until appropriate treatment has been given.

Congenital Hypothyroidism: A Review of 2020 European Society for Pediatric Endocrinology and the European Society for Endocrinology Consensus Guidelines

Congenital Hypothyroidism: A Review of 2020 European Society for Pediatric Endocrinology and the European Society for Endocrinology Consensus Guidelines

Levothyroxine and subclinical hypothyroidism in patients with recurrent pregnancy loss.

The association between subclinical hypothyroidism (SCH) and recurrent pregnancy loss (RPL) remains unclear. We evaluated whether SCH affects subsequent live births and whether levothyroxine is effective in improving the live birth rate in patients with RPL. This observational cohort study included 1418 pregnancies of 1014 patients with a history of 2 or more pregnancy losses, who were euthyroid or had hypothyroidism, and had at least one subsequent pregnancy outcome. Some patients with SCH, as defined as a TSH >2.5mIU/L, were treated with levothyroxine, and these comprised the levothyroxine group. The prevalence of SCH, subsequent live birth rates per patient and per pregnancy were compared among patients with SCH treated with and without levothyroxine and patients with euthyroid. The prevalence of SCH was 14.4%. Subsequent live birth rates were 75.0% for the levothyroxine group, 68.6% for the untreated SCH group, and 70.1% for the euthyroid group. After excluding miscarriages with abnormal karyotypes, live birth rates were 89.2%, 90.0%, and 91.1%. The adjusted odds ratio (95%CI) was 0.95 (0.23-3.83) after controlling covariables when comparing SCH patients with and without treatment. The live birth rates per pregnancy were 93.1%, 85.7%, and 90.9%, respectively. The adjusted OR was 0.95 (0.23-3.83). Levothyroxine has no effect on improving the live birth rate in patients with RPL associated with SCH. Treatment in patients with RPL and SCH raised TSH levels (2.5-10mIU/L) might not be beneficial in improving the live birth rate.

Subclinical hypothyroidism and the risk of cancer incidence and cancer mortality: a systematic review

BackgroundThyroid hormone has been shown to be involved in carcinogenesis via its effects on cell proliferation pathways. The objective of this study is to determine the association between subclinical hypothyroidism (SCH) and the risk of incident cancer and cancer mortality via systematic review.MethodsA systematic search was performed on Medline and Pubmed to identify relevant studies. Randomized controlled trials, and observational studies assessing SCH or its treatment and the risk of incident cancer or cancer mortality were identified.ResultsA total of 7 cohort and 2 case-control studies met our inclusion criteria. In general, these studies were of medium to good quality. Overall, studies revealed no association between SCH and breast and prostate cancer. One study found that untreated SCH may be associated with an increased risk of colorectal cancer (adjusted odds ratio [OR]: 1.16; 95% confidence interval [CI]: 1.08–1.24). One study showed an increased risk in thyroid cancer incidence (adjusted OR: 3.38; 95% CI: 2.05–5.59) associated with elevation of a thyroid stimulating hormone (TSH) of > 1.64mIU/L. Two studies found an increase in cancer mortality among patients with SCH compared to euthyroid individuals; in contrast one study found no association between subclinical hypothyroidism and cancer mortality among aging men.ConclusionThe number of studies examining thyroid dysfunction and cancer risk and mortality is limited. Future studies assessing the association between thyroid dysfunction and cancer risk and mortality are needed, which will further address the need to treat subclinical hypothyroidism.

Macroprolactinemia Attenuates the Impact of Levothyroxine on Hypothalamic-Pituitary-Thyroid Axis Activity and Thyroid Autoimmunity in Women With Autoimmune Hypothyroidism.

Because of contradictory results, clinical significance of elevated levels of macroprolactin (macroprolactinemia) remains unclear. The aim of this study was to investigate whether macroprolactinemia determines levothyroxine action on hypothalamic-pituitary-thyroid axis activity and thyroid antibody titers in women with autoimmune hypothyroidism. The study population included 2 age-, body mass index-, hormone-, and thyroid antibody-matched groups of premenopausal women with untreated autoimmune subclinical hypothyroidism: 15 subjects with coexisting macroprolactinemia and 29 individuals with prolactin levels within the reference range. All included patients were then treated with levothyroxine for 6 months. Serum levels of thyrotropin, free thyroid hormones, prolactin and 25-hydroxyvitamin D, titers of thyroid peroxidase and thyroglobulin antibodies, as well as macroprolactin content were assessed at the beginning and at the end of the study. Except for 25-hydroxyvitamin D levels and macroprolactin content, there were no significant differences between both study arms in the investigated markers. All participants completed the study. In both treatment arms, levothyroxine treatment decreased thyrotropin levels, increased free thyroxine and free triiodothyronine levels, as well as reduced thyroid peroxidase titers, but this effect was less pronounced in women with macroprolactinemia. In women with normal prolactin levels, levothyroxine reduced also thyroglobulin antibody titers and increased 25-hydroxyvitamin D levels. In this group of patients, treatment-induced changes in hormone levels and thyroid antibody titers correlated with treatment-induced changes in 25-hydroxyvitamin D levels. The obtained results suggest that macroprolactin excess attenuates the impact of levothyroxine on hypothalamic-pituitary-thyroid axis activity and thyroid autoimmunity.

Cognitive Function in Children With Idiopathic Subclinical Hypothyroidism: Effects of 2 Years of Levothyroxine Therapy.

Long-term consequences of mild subclinical hypothyroidism (SH) in children are still unclear, and the need for levothyroxine (L-T4) supplementation remains controversial. We designed a 2-year, case-control, prospective study of a cohort of children with SH to evaluate the effects of L-T4 therapy on neurocognitive outcome. Thirty-four children, age 9.1 ± 2.6 years, with long-lasting, idiopathic, and mild SH, and 34 healthy matched controls, were enrolled. Twenty SH children underwent a 2-year L-T4 treatment (group A), whereas 14 refused treatment and were reevaluated after a 2-year-follow-up (group B). IQ and specific cognitive domains were evaluated in all children at study entry and after 2 years of therapy (group A) or observation (group B) in SH individuals. In SH children baseline IQ scores were normal and comparable to controls (full-scale IQ [FSIQ] 100.4 ± 11.3 vs 101.8 ± 14.2, verbal IQ [VIQ] 99.7 ± 13.7 vs 98.3 ± 14.9 and performance IQ [PIQ] 101.2 ± 10.4 vs 105 ± 10.4).In group A, L-T4 treatment was associated with normalization of thyrotropin (6.3 ± 1.0 mIU/L at baseline vs 2.8 ± 1.4 mIU/L at 2 years, P < .001). However, 2-year L-T4 therapy was not associated with a change in IQ scores (FSIQ 104.4 ± 13.8 vs 102.7 ± 11.0; VIQ 101.8 ± 14.9 vs 102.3 ± 11.9; and PIQ 106.5 ± 13.9 vs 102.7 ± 10.7) or in verbal or performance subtest scores. No significant differences were found in IQ scores after 2 years of treatment in group A compared to group B after a 2-year follow-up. Our data suggest neurocognitive function in children is not impaired by persistent, mild, untreated SH and is not significantly modified by 2-year L-T4 supplementation.

Effect of acute aerobic exercise on arterial stiffness and thyroid-stimulating hormone in subclinical hypothyroidism.

Acute exercise has been reported to increase thyroid hormone levels and decrease arterial stiffness in healthy young subjects. However, the effect of acute aerobic exercise on circulating thyroid hormone levels and arterial stiffness in patients with subclinical hypothyroidism remains unclear. The aim of this study was to investigate the effects of acute aerobic exercise on arterial stiffness and thyroid hormone levels, and any relationship between these endpoints, in patients with subclinical hypothyroidism. We studied patients with untreated subclinical hypothyroidism (n = 53, 65 ± 12years old) compared with euthyroid subjects (n = 55, 64 ± 10years old). Exercise analysis was performed with a ramp cycle ergometer test. Arterial stiffness (cardio-ankle vascular index, CAVI) was measured at baseline and 5min after exercise. We collected participant blood samples for serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) measurements before and 5min after exercise. The CAVI and serum TSH levels significantly decreased after exercise in the subclinical hypothyroidism group (CAVI; 8.1 ± 1.6 vs. 8.5 ± 1.5, p < 0.001, TSH; 6.7 ± 1.4 vs. 7.6 ± 1.2 μIU/ml, p < 0.001) and euthyroid group (CAVI; 7.6 ± 1.0 vs. 8.3 ± 0.9, p < 0.001, TSH; 2.2 ± 1.1 vs. 2.4 ± 1.2 μIU/ml, p = 0.005). The changes in CAVI from baseline compared with after exercise were lower, in absolute values, in the subclinical hypothyroidism group than in the euthyroid group (subclinical hypothyroidism group vs euthyroid group; ΔCAVI: - 0.4 ± 0.6 vs. - 0.7 ± 0.7, p = 0.012). The changes in serum TSH from baseline to after exercise were higher, in absolute values, in the subclinical hypothyroidism group than in the euthyroid group (subclinical hypothyroidism group vs euthyroid group; Δ serum TSH: - 1.3 ± 1.4 vs. - 0.3 ± 0.5, p < 0.001). The changes in CAVI from baseline to after exercise were negatively correlated with changes in TSH (r = - 0.32, p = 0.038) in the subclinical hypothyroidism group. In conclusion, acute aerobic exercise decreased both arterial stiffness and serum TSH levels in patients with subclinical hypothyroidism and euthyroid subjects. While the absolute change in arterial stiffness decreased, the absolute change in serum TSH levels increased in patients with subclinical hypothyroidism compared with euthyroid subjects. These data suggest that subclinical hypothyroidism reduces CAVI during acute aerobic exercise. Further changes in absolute levels of serum TSH in subclinical hypothyroidism may result in reduced CAVI improvement by acute aerobic exercise.

Pregnancy outcomes of antibody negative and untreated subclinical hypothyroidism

Subclinical hypothyroidism is thought to be associated with adverse pregnancy outcomes but the data is conflicting and generally depends on antibody positivity and treatment. We evaluated the pregnancy outcomes in Turkish population with untreated, antibody negative subclinical hypothyroidism for the first time. We searched for 30 015 patients between January 2016 and May 2017 retrospectively. Finally, a total of 930 pregnant women with untreated, antibody negative subclinical hypothyroidism and 7986 controls were included. Demographic characteristics, laboratory findings and pregnancy outcomes, including pregnancy loss, impaired glucose tolerance, gestational diabetes, hypertensive disorders of pregnancy, preterm birth, neonatal intensive care unit admission, placenta previa and abruption, cesarean delivery, low birthweight, Apgar score <7 and premature rupture of membranes were recorded. Demographic and laboratory characteristics were similar between two groups except thyroid stimulating hormone levels and previous uterine surgery rates. Subclinical hypothyroidism group had an increased risk of pregnancy loss (odds ratio [OR] 2.583; 95% confidence interval [CI] 1.982-3.365; P < 0.001), impaired glucose tolerance (OR 1.952; 95% CI 1.450-2.627; P < 0.001), hypertensive disorders of pregnancy (OR 1.476; 95% CI 1.113-1.923; P = 0.004), neonatal intensive care unit admission (OR 1.620; 95% CI 1.084-2.420; P = 0.019), placenta previa (OR 12.581; 95% CI 5.046-31.363; P < 0.001) and cesarean delivery (OR 1.263; 95% CI 1.091-1.462; P = 0.002). Subclinical hypothyroidism has worse pregnancy outcomes as compared to euthyroid pregnant women even in antibody negativity. Therefore, we suggest that all pregnant women should routinely be screened in their first antenatal visits for thyroid functions.

Marked improvement of thyroid function and autoimmunity by Aloe barbadensis miller juice in patients with subclinical hypothyroidism

Some natural compounds decrease serum levels of thyroid autoantibodies, but results are inconsistent and thyroid function has been evaluated infrequently; moreover, the effects of Aloe on thyroid autoimmunity and function have been examined in very few studies. This study stems from the observation of one co-author, who has Hashimoto’s thyroiditis (HT)-related subclinical hypothyroidism (SCH). Upon checking her biochemical thyroid panel when taking daily Aloe barbardensis Miller juice (ABMJ) for thyroid-unrelated reasons, she noticed a decrease in serum thyroperoxidase autoantibodies (TPOAb) and thyrotropin (TSH) and an increase in serum free thyroxine (FT4). Based on this observation, we enrolled 30 consecutive HT women with levothyroxine-untreated SCH and high TPOAb levels. All of them took ABMJ (50 ml daily) for nine months and were tested for serum TSH, FT4, free triiodothyronine (FT3) and TPOAb. Measurements were performed at baseline and at months 3 and 9. TSH, FT4 and TPOAb improved significantly already at month 3 and further (−61%, +23% and −56%) at month 9. However, FT3 decreased significantly at month 3 (−16%) with no further decrease at month 9, so that the FT4:FT3 ratio increased significantly (+33% and + 49%). At baseline, 100% of women had TSH > 4.0 mU/L and TPOAb > 400 U/ml, but frequencies fell to 0% and 37%, respectively, at month 9. In contrast, a control group (namely, 15 untreated SCH women of comparable age and baseline levels of TSH, FT4, FT3 and TPOAb) had no significant changes in any index. We conclude that the daily intake of 100 ml ABMJ for 9 months in women with HT-related SCH decreases the burden of thyroid autoimmune inflammation. In addition, ABMJ rescues thyrocyte function, with decreased need for conversion of the prohormone T4 into the more active T3 through ABMJ-induced inhibition of T4 deiodination.

A clinical analysis of subclinical hypothyroidism during pregnancy and the effect of thyroxine replacement therapy

Objective To investigate the maternal and fetal outcomes of pregnant women with subclinical hypothyroidism, and clinical observation of thyroxine replacement. Methods From March 2014 to March 2015, the clinical records of 216 women with subclinical hypothyroidism(including 166 cases with thyroxine replacement), and hypothyroidism(n=69)during pregnancy who delivered at our hospital were reviewed. The maternal complications and neonatal outcomes were compared with 406 healthy women who delivered during the same period. Results The age, number of fetus, and morbidity rate of gestational hypertension were without significant differences in those groups. The morbidity of gestational diabetes in subclinical hypothyroidism group and hypothyroidism group were significantly higher than those in control group(13.4%, 17.4% vs 0.2%, P 0.05). Further compared those between treated and untreated subclinical hypothyroidism, the results were also without significant difference(P>0.05). Conclusions Subclinical hypothyroidism had no significant influence on pregnancy outcomes and perinatal events. Thyroxine replacement in subclinical hypothyroidism pregnant women also had no significant influence on pregnancy outcomes and perinatal events. (Chin J Endocrinol Metab, 2017, 33: 198-202) Key words: Pregnancy; Subclinical hypothyroidism; Thyroxine; Pregnancy outcome; Perinatal events

Population-Based National Prevalence of Thyroid Dysfunction in Spain and Associated Factors: Di@bet.es Study.

The aim of this study was to investigate the national prevalence of thyroid dysfunction in Spain and its association with various clinical, environmental, and demographic variables. The study included 4554 subjects (42.4% men) with a mean age of 50 years (range 18-93 years), who were participants in a national, cross-sectional, population-based survey conducted in 2009-2010. Data gathered included clinical and demographic characteristics, physical examination, and blood sampling. Thyrotropin, free thyroxine, free triiodothyronine, and thyroid peroxidase antibody (TPOAb) concentrations were analyzed by electrochemiluminescence. Urinary iodine (UI) levels were measured in an isolated urine sample. The prevalence of treated hypothyroidism, untreated subclinical hypothyroidism, and untreated clinical hypothyroidism was 4.2% [confidence interval (CI) 3.6-4.9%], 4.6% [CI 4.0-5.2%], and 0.3% [CI 0.1-0.5%], respectively. The prevalence of total hypothyroidism (including all fractions) was 9.1% [CI 8.2-10.0%]. The prevalence of total hyperthyroidism was 0.8% [CI 0.6-1.1]. A total of 7.5% [CI 6.7-8.3%] of the population tested positive for TPOAbs (≥50 IU/mL). In multivariate logistic regression models, TPOAbs were strongly associated with both hypothyroidism (p < 0.001) and hyperthyroidism (p = 0.005), whereas high UI levels (>200 μg/g creatinine) were associated with hypothyroidism (p < 0.001). The positive association between UI and hypothyroidism remained for both treated (p < 0.001) and untreated (p < 0.05) hypothyroidism, whereas it was especially significant for non-autoimmune (TPOAbs negative) forms (p < 0.001). At UI levels ≥200 μg/g, there was a positive correlation between UI and thyrotropin levels (β = 0.152, p < 0.001) and a negative correlation between UI and free triiodothyronine levels (β = -0.134, p = 0.001). According to the data, a large proportion (10%) of the Spanish population has some evidence of thyroid dysfunction. High TPOAb concentrations were associated with both hypo- and hyperthyroidism, whereas high UI concentrations were associated with hypothyroidism.

Study of anemia in primary hypothyroidism

Context: Thyroid hormones directly or indirectly, through erythropoietin, stimulate growth of erythroid colonies. In the deficiency of thyroid hormones, anemia frequently develops and may be normocytic, hypochromic-microcytic, or macrocytic. Aims: In this study, we evaluated the types of anemia and its causes in patients with untreated primary hypothyroidism. Settings and Design: This is an observational study conducted at department of general medicine of a tertiary care center. The duration of study was 1 year, November 2015–October 2016. Subjects and Methods: Four hundred and seventy-two patients of overt hypothyroidism or subclinical hypothyroidism were evaluated for possible inclusion in this study. Out of these 112 participants were recruited for the study after fulfilling inclusion criteria. Statistical Analysis Used: Microsoft Excel® and SPSS® 20 for Windows® were used for data storage and analysis. The qualitative data were expressed in percentages, and quantitative data were expressed as mean ± standard deviation. Student's t-test and Chi-square test were used to determine statistical difference between variables. Results: In our study, anemia frequency was 18% in the subclinical hypothyroid patients and 11% in the overt hypothyroid group. In the subgroup analysis of the hypothyroid patients, anemia of chronic disease was most common anemia in patients with overt and subclinical hypothyroidism. Conclusions: Anemia is a common finding in overt hypothyroidism, but anemia is not listed among the consequences of untreated subclinical hypothyroidism. Type and cause of anemia is also different in overt and subclinical hypothyroid patients. Therefore, anemia in hypothyroidism needs to be properly evaluated because treatment varies with etiology of anemia.

Subclinical hypothyroidism in childhood - current knowledge and open issues.

Subclinical hypothyroidism is defined as serum levels of TSH above the upper limit of the reference range, in the presence of normal concentrations of total T4 or free T4. This biochemical profile might be an indication of mild hypothyroidism, with a potential increased risk of metabolic abnormalities and cardiovascular disease recorded among adults. Whether subclinical hypothyroidism results in adverse health outcomes among children is a matter of debate and so management of this condition remains challenging. Mild forms of untreated subclinical hypothyroidism do not seem to be associated with impairments in growth, bone health or neurocognitive outcome. However, ongoing scientific investigations have highlighted the presence of subtle proatherogenic abnormalities among children with modest elevations in their TSH levels. Although current findings are insufficient to recommend levothyroxine treatment for all children with mild asymptomatic forms of subclinical hypothyroidism, they highlight the potential need for assessment of cardiovascular risk among children with this condition. Increased understanding of the early metabolic risk factors associated with subclinical hypothyroidism in childhood will help to improve the management of affected individuals.