RESUMO
Objective: To evaluate the association of TSH, free T3 (FT3), free T4 (FT4), and conversion (FT3:FT4) ratio values with incident hypertension. Materials and methods: The study included data from participants of the ELSA-Brasil study without baseline hypertension. Serum TSH, FT4 and FT3 levels, and FT3:FT4 ratio values were assessed at baseline, and incident hypertension (defined by blood pressure levels ≥ 140/90 mmHg) was estimated over a median of 8.2 years of follow-up. The risk of incident hypertension was evaluated considering a 1-unit increase in TSH, FT4, FT3, and conversion ratio values and after dividing these variables into quintiles for further analysis using Poisson regression with robust variance. The results are presented as relative risks (RR) and 95% confidence intervals (CIs) before and after adjustment for multiple variables. Results: The primary analysis incorporated data from 5,915 euthyroid individuals, and the secondary analysis combined data from all euthyroid individuals, 587 individuals with subclinical hypothyroidism, and 31 individuals with subclinical hyperthyroidism. The rate of incident hypertension was 28% (95% CI: 27%-29.3%). The FT4 levels in the first quintile (0.18-1.06 ng/dL) were significantly associated with incident hypertension (RR: 1.03, 95% CI: 1.01-1.06) at follow-up. The association between FT4 levels in the first quintile and incident hypertension was also observed in the analysis of combined data from euthyroid individuals and participants with subclinical thyroid dysfunction (RR: 1.04, 95% CI: 1.01-1.07). The associations were predominantly observed with systolic blood pressure levels in euthyroid individuals. However, in the combined analysis incorporating euthyroid participants and individuals with subclinical thyroid dysfunction, the associations were more pronounced with diastolic blood pressure levels. Conclusion: Low FT4 levels may be a mild risk factor for incident hypertension in euthyroid individuals and persons with subclinical thyroid dysfunction.
Assuntos
Hipertensão , Tireotropina , Tiroxina , Tri-Iodotironina , Humanos , Hipertensão/epidemiologia , Hipertensão/sangue , Masculino , Feminino , Brasil/epidemiologia , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Longitudinais , Adulto , Tireotropina/sangue , Incidência , Tiroxina/sangue , Tri-Iodotironina/sangue , Hipertireoidismo/sangue , Hipertireoidismo/epidemiologia , Hipotireoidismo/sangue , Hipotireoidismo/epidemiologia , Fatores de Risco , Testes de Função Tireóidea , IdosoRESUMO
PURPOSE: We aimed to perform a systematic review and meta-analysis addressing the efficacy of levothyroxine therapy in pregnant women with subclinical hypothyroidism considering most recent evidence and subgroups of interest for clinical practice. METHODS: PubMed, Embase, and Cochrane Central were searched from inception for randomized controlled trials (RCTs) comparing levothyroxine with placebo or no intervention in pregnant women with subclinical hypothyroidism. We used a random-effects model and conducted subgroup analyses based on thyroid peroxidase antibody status, thyroid stimulating hormone levels, fertility treatment, and recurrent miscarriage. RESULTS: We included 11 RCTs comprising 2,749 pregnant women with subclinical hypothyroidism. Patients treated with levothyroxine (1,439; 52.3%) had significantly lower risk of pregnancy loss (risk ratio 0.69; 95% confidence interval 0.52-0.91; p < 0.01; 6 studies). However, there was no significant association between levothyroxine and live birth (risk ratio 1.01; 95% confidence interval 0.99-1.03; p = 0.29; 8 studies). No statistically significant interaction was observed across subgroups (p > 0.05). CONCLUSION: Levothyroxine replacement therapy for subclinical hypothyroidism during pregnancy may decrease pregnancy loss when early prescribed. Nevertheless, further investigation is needed in patients with thyroid stimulating hormone above four milliunits per liter, especially when associated with recurrent miscarriage or infertility.
Assuntos
Hipotireoidismo , Complicações na Gravidez , Ensaios Clínicos Controlados Aleatórios como Assunto , Tiroxina , Humanos , Gravidez , Feminino , Hipotireoidismo/tratamento farmacológico , Hipotireoidismo/sangue , Tiroxina/uso terapêutico , Complicações na Gravidez/tratamento farmacológico , Tireotropina/sangue , Aborto Habitual/prevenção & controle , Aborto Habitual/tratamento farmacológicoRESUMO
CONTEXT: The effectiveness of levothyroxine (LT4) in restoring thyroid hormone (TH) homeostasis, particularly serum thyroxine (T4) and triiodothyronine (T3) levels, remains debatable. OBJECTIVE: This work aimed to assess TH homeostasis in LT4-treated individuals using data from the Longitudinal Study of Adult Health in Brazil (ELSA-Brasil) study. METHODS: The ELSA-Brasil study follows 15 105 adult Brazilians (aged 35-74 years) over 8.2 years (2008-2019) with 3 observation points assessing health parameters including serum thyrotropin (TSH), free T4 (FT4), and free T3 (FT3) levels. We analyzed 186 participants that initiated treatment with LT4 during the study, and 243 individuals continuously treated with LT4 therapy. RESULTS: Initiation of therapy with LT4 resulted in an 11% to 19% decrease in TSH, an approximately 19% increase in FT4, and a 7% reduction in FT3 serum levels (FT3 dropped >10% in â¼40% of the LT4-treated patients). This was associated with an increase in triglyceride levels and utilization of hypolipidemic and antidiabetic medications. Participants continuously treated with LT4 exhibited a stable elevation in serum FT4 and a reduction in serum FT3 and TSH levels. While 115 participants (47.3%) had at least 1 serum FT4 levels above the control reference range (>1.52â ng/dL), 38 participants (15.6%) had at least 1 serum FT3 below the reference range (<0.23â ng/dL). CONCLUSION: The present results challenge the dogma that treatment with LT4 for hypothyroidism restores TH homeostasis in all patients. A substantial number of LT4-treated patients exhibit repeated FT4 and FT3 levels outside the normal reference range, despite normal TSH levels. Further studies are needed to define the clinical implications of these findings.
Assuntos
Homeostase , Hipotireoidismo , Tiroxina , Humanos , Pessoa de Meia-Idade , Tiroxina/uso terapêutico , Tiroxina/sangue , Tiroxina/administração & dosagem , Feminino , Masculino , Adulto , Homeostase/efeitos dos fármacos , Hipotireoidismo/tratamento farmacológico , Hipotireoidismo/sangue , Estudos Longitudinais , Idoso , Brasil , Hormônios Tireóideos/sangue , Tri-Iodotironina/sangue , Tireotropina/sangue , Testes de Função Tireóidea , Terapia de Reposição Hormonal/métodosRESUMO
El Hipotiroidismo subclínico (HSC) es definido bioquímicamente por una elevación en la concentración sérica de la hormona TSH con niveles normales de T4 libre. El objetivo de este estudio fue determinar la prevalencia de HSC en los pacientes que asistieron a la consulta de medicina interna del Hospital General IESS de Riobamba. Así como, analizar la correlación entre los parámetros hormonales y ciertos marcadores bioquímicos asociados con el incremento de riesgo cardiovascular. Se realizó una investigación de tipo descriptiva, observacional, con un diseño no experimental de corte transversal, que abarcó el periodo comprendido desde enero de 2019 hasta septiembre de 2021. 245 pacientes fueron diagnosticados con HSC, lo cual representó el 10.58 % del universo poblacional estudiado, 61.2% eran del sexo femenino, mientras que el 38.8% del sexo masculino. El mayor número de casos (59.61 %) se observó en el grupo etario mayor de 65 años, distribuidos de la siguiente manera: (22.86% hombres y 36.75% mujeres), también se encontró que el HSC está asociado con un perfil lipídico aterogénico, caracterizado por un incremento en la concentración de colesterol total y LDL los cuales se correlacionaron positivamente con las concentraciones de TSH.
Subclinical hypothyroidism (SH) is biochemically defined by an elevation in the serum concentration of TSH hormone with normal levels of free T4. The aim of this study was to determine the prevalence of SH in patients attending the internal medicine clinic of the General Hospital IESS of Riobamba. Also, to analyze the correlation between hormonal parameters and certain biochemical markers associated with increased cardiovascular risk. A descriptive, observational, non-experimental cross-sectional design was performed, covering the period from January 2019 to September 2021. 245 patients were diagnosed with SH, which represented 10.58 % of the population universe studied, 61.2% were female, while 38.8% were male. The highest number of cases (59.61 %) was observed in the age group over 65 years, distributed as follows: (22.86% men and 36.75% women), it was also found that SH is associated with an atherogenic lipid profile, characterized by an increase in the concentration of total cholesterol and LDL which correlated positively with TSH concentrations.
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Adulto Jovem , Fatores de Risco de Doenças Cardíacas , Hipotireoidismo/epidemiologia , Tireotropina/sangue , Biomarcadores/sangue , Prevalência , Estudos Transversais , Distribuição por Idade e Sexo , Aterosclerose/diagnóstico , Aterosclerose/sangue , Hipotireoidismo/diagnóstico , Hipotireoidismo/sangue , Lipídeos/sangueRESUMO
Un estudio mostró que el aumento de valores de la hormona estimulante de la tiroides se asoció a un aumento de mortalidad por todas las causas, estimando que las enfermedades cardiovasculares mediaban dicha asociación en aproximada-mente el 14 % de los casos. Asimismo se observó que el reemplazo con levotiroxina disminuiría los niveles de colesterol, lo cual podría tener un efecto en la reducción de enfermedades cardiovasculares. Partiendo de una viñeta clínica la autora intenta, a través de una búsqueda bibliográfica y análisis de la evidencia, determinar si el tratamiento del hipotiroidismo subclínico en adultos mayores reduciría la morbimortalidad por eventos cardiovasculares. (AU)
A study showed that increased thyroid-stimulating hormone levels were associated with increased all-cause mortality, with cardiovascular disease estimated to mediate this association in approximately 14 % of cases. Additionally, levothyroxine replacement was found to lower cholesterol levels, which could have an effect in reducing cardiovascular diseases. Basedon a clinical vignette, the author attempts, through a literature search and an analysis of the evidence, to determine whether treatment of subclinical hypothyroidism in older adults would reduce morbidity and mortality from cardiovascular events. (AU)
Assuntos
Humanos , Feminino , Idoso , Tiroxina/uso terapêutico , Doenças Cardiovasculares/mortalidade , Doenças Cardiovasculares/prevenção & controle , Hipotireoidismo/tratamento farmacológico , Indicadores de Morbimortalidade , Fatores Etários , Hipotireoidismo/sangueRESUMO
INTRODUCTION: Hypothyroidism has been associated with dyslipidemia. Its treatment with levothyroxine has shown a positive effect on the lipid profile in adults, however, there is a lack of data on the pediatric popu lation. OBJECTIVE: to evaluate the effect of the thyroid profile normalization on the lipid profile in children with primary hypothyroidism. PATIENTS AND METHOD: Retrospective study in children aged from 6 to 16 years, with diagnosis of primary hypothyroidism due to Hashimoto's thyroiditis, in treatment with levothyroxine, and who had an evaluation of serum lipids before and during their treatment. The lipid profile was evaluated in 2 stages: the first one referred to as "before levothyroxine treatment" (at the diagnosis of primary hypothyroidism) and the second one referred to as " thyroid profile normalization" (when normalization of Thyroid-stimulating hormone [TSH] and free T4 [FT4] was achieved during levothyroxine treatment). Sociodemographic and anthropometric data were recorded. The lipid profile evaluation consisted of the serum determination of total cholesterol (TC), high-density cholesterol (HDL-C), and TG. The phenotype of dyslipidemias was determined according to the Fredrickson's classification. RESULTS: 72 patients were included (61% women; age 11.5 ± 2.9 years), out of which 58.3% (n = 42) presented pre-treatment dyslipidemia. In hypothyroid state, it was evident the correlation of TSH with TC (r = 0.36; p = 0.002), LDL-C (r = 0.46; p = 0.01), and HDL-C (r = -0.33; p = 0.004). The thyroid profile normalization showed the reduction of TC [184 mg/dL (IQR 92-322) vs 147 mg/dL (IQR 92-283); p = 0.05], LDL-C [99 mg/dL (IQR 44-232) vs 82 mg/dL (IQR 41-168); p = 0.02], TG [113 mg/dL (IQR 50-483) vs 88 mg/dL (IQR 16-343); p = 0.03], and the frequency of dyslipidemia [58.3% vs 22.2%; p = 0.001), as well as the TC correction with TG (r = 0.35; p = 0.02) and LDL-C (r = 0.88; p = 0.01). Persistent dyslipidemia was associated with obesity (r = 0.27; p = 0.02), overweight (r = 0.58; p = 0.001), and pre-treatment dyslipidemia (r = 0.53; p = 0.001). CONCLUSIONS: There is an association between TSH, TC, LDL-C, and HDL-C in hypothyroidism. When the thyroid profile was normalized, there was a reduction of TC, TG, LDL- C, and dyslipidemia frequency. Persistent dyslipidemia was associated with obesity, overweight, and pre-treatment dyslipidemia.
Assuntos
Hipotireoidismo/sangue , Lipídeos/sangue , Tireotropina/sangue , Tiroxina/sangue , Adolescente , Criança , Colesterol/sangue , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Dislipidemias/sangue , Dislipidemias/classificação , Dislipidemias/complicações , Feminino , Doença de Hashimoto/complicações , Humanos , Hipotireoidismo/tratamento farmacológico , Hipotireoidismo/etiologia , Masculino , Obesidade Infantil/etiologia , Valores de Referência , Estudos Retrospectivos , Tiroxina/uso terapêutico , Triglicerídeos/sangueRESUMO
To verify the viability and functionality of cryopreserved thyroid autotransplantation in rats who underwent total thyroidectomy in the treatment of postoperative hypothyroidism. Thirty-two Wistar rats were randomly assigned into groups (G) with eight animals each: control (CG); simulation (SG); hypothyroidism (HTG) and transplanted (TG). At the beginning and in the 13th week of the experiment, serum levels of total T3, free T4, TSH and calcium were determined. In both the first and 14th weeks, scintigraphic examinations, 99m-Tc pertechnetate radioisotope biodistribution and histopathology were performed. In the 14th week, the expression of proliferating cell nuclear antigen (PCNA) and cellular apoptosis (caspase-3) were also evaluated. In the 13th week, the transplanted animals had normal serum levels of total T3 and free T4. TSH levels showed a tendency towards normality. In the 14th week, scintigraphic exams displayed graft isotopic uptake in all animals in the TG group. Histological examinations 13 weeks after transplantation showed the viability and functionality of thyroid follicles. PCNA revealed significant immunoreactivity of the graft (p < 0.001) when the TG was compared to the CG. There was no difference between CG and TG considering the expression of activated caspase-3. The experimental study confirmed the viability and functionality of thyroid autotransplantation implanted in skeletal muscle with evidence of cell proliferation without cellular apoptosis. This surgical strategy was effective in the treatment of postoperative hypothyroidism.
Assuntos
Hipotireoidismo/cirurgia , Complicações Pós-Operatórias/cirurgia , Glândula Tireoide/transplante , Tireoidectomia/efeitos adversos , Animais , Hipotireoidismo/sangue , Hipotireoidismo/etiologia , Masculino , Complicações Pós-Operatórias/sangue , Complicações Pós-Operatórias/etiologia , Ratos , Ratos Wistar , Tiroxina/sangue , Transplante Autólogo , Tri-Iodotironina/sangueRESUMO
Both the cholinergic pathway and oxidative stress are important mechanisms involved in the pathogenesis of hypothyroidism, a condition characterized by low levels of thyroid hormone that predispose the patient to brain dysfunction. Phenolic compounds have numerous health benefits, including antioxidant activity. This study evaluates the preventive effects of resveratrol in the cholinergic system and redox status in rats with methimazole-induced hypothyroidism. Hypothyroidism increases acetylcholinesterase (AChE) activity and density in the cerebral cortex and hippocampus and decreases the α7 and M1 receptor densities in the hippocampus. Hypothyroidism also increases cellular levels of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS), but reduces total thiol content, and catalase and superoxide dismutase activities in the serum. In the cerebral cortex and hippocampus, hypothyroidism increases the levels of ROS and nitrites. In this study, resveratrol (50 mg/kg) treatment prevents the observed increase in AChE in the cerebral cortex, and increases the protein levels of NeuN, a marker of mature neurons. Resveratrol also prevents changes in serum ROS levels and brain structure, as well as the levels of TBARS, total thiol content, and serum catalase enzyme activity. These collective findings suggest that resveratrol has a high antioxidant capacity and can restore hypothyroidism-triggered alterations related to neurotransmission. Thus, it is a promising agent for the prevention of brain damage resulting from hypothyroidism.
Assuntos
Colinérgicos/metabolismo , Hipotireoidismo/metabolismo , Hipotireoidismo/patologia , Neuroproteção/efeitos dos fármacos , Resveratrol/farmacologia , Transdução de Sinais , Acetilcolinesterase/metabolismo , Animais , Antígenos Nucleares/metabolismo , Modelos Animais de Doenças , Proteína Glial Fibrilar Ácida/metabolismo , Hipocampo/metabolismo , Hipotireoidismo/sangue , Masculino , Proteínas do Tecido Nervoso/metabolismo , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos Wistar , Receptores Colinérgicos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Tiroxina/sangue , Tri-Iodotironina/sangueRESUMO
INTRODUCCIÓN: El hipotiroidismo subclínico (HSC) se define bioquímicamente por una elevación en la concentración sérica de la hormona estimulante de la tiroides (TSH), con niveles normales de tiroxina libre (T4L). La asociación entre el HSC y el daño cardiovascular ha sido un tema controversial. OBJETIVO: determinar la asociación entre el HSC y el desarrollo de la enfermedad cardiovascular mediante la cuantificación de la proteína C reactiva ultrasensible PCR-us y la determinación de lípidos circulantes asociados a la enfermedad cardiovascular y la ateroesclerosis. MÉTODOS: Estudio descriptivo, correlacional de corte transversal realizado en el Hospital IESS de Riobamba, Ecuador en el periodo comprendido desde enero a diciembre de 2019. Se estudiaron 70 individuos (40 pacientes con HSC y 30 controles) con edades entre 18 y 75 años. Se realizaron las historias clínicas y el examen físico a cada paciente y la toma de las muestras sanguíneas para determinar la concentración sérica de los siguientes parámetros bioquímicos y hormonales: colesterol total, triglicéridos, HDL colesterol y LDL colesterol, TSH, T4L y PCR-us. RESULTADOS: Se encontró un incremento significativo en la concentración de colesterol total (p<0.0001), LDL colesterol (p<0.01) y PCR-us (p<0.0001) en los pacientes con HSC vs los controles. Se observó una correlación positiva (p<0.0001; r=0.9148) entre la TSH y la PCR-us en los pacientes con HSC. CONCLUSIÓN: los pacientes con HSC experimentan una elevación en los niveles séricos de PCR-us la cual está correlacionada con un incremento en la concentración sérica de TSH. Estos parámetros asociados a un aumento del colesterol total y de la LDL colesterol sugieren un estado inflamatorio de bajo grado que podría estar asociado con el desarrollo de aterosclerosis y daño cardiovascular.
INTRODUCTION: Subclinical hypothyroidism (SH) is defined biochemically by an elevation in serum thyroid stimulating hormone (TSH) concentration, with normal levels of free thyroxine (T4L). The association between SH and cardiovascular damage has been a controversial issue. OBJECTIVE: to determine the association between SH and the development of cardiovascular disease through the quantification of the high sensitivity C-reactive protein (hs-PCR) and the determination of circulating lipids associated to cardiovascular disease and atherosclerosis. METHODS: Observational, correlational cross-sectional study with patients captured in the internal medicine office as well as those attending screening activities at the IESS Hospital in Riobamba- Ecuador, in the period from January to December 2019. Seventy individuals (40 patients with SH and 30 controls) between the ages of 18 and 75 years were studied. Each patient's medical history and physical examination were performed, and blood samples were taken to determine the serum concentration of the following biochemical and hormonal parameters: total cholesterol, triglycerides, HDL cholesterol and LDL cholesterol, TSH, T4L and hs-PCR. RESULTS: A significant increase in the concentration of total cholesterol (p<0.0001), LDL cholesterol (p<0.01) and hs-PCR (p<0.0001) was found in patients with SH vs. controls. A positive correlation (p<0.0001; r=0.9148) was observed between TSH and hs-PCR in patients with SH. CONCLUSION: patients with SH experience an elevation in serum hs-PCR levels which is correlated with an increase in serum TSH concentration. These parameters associated with an increase in total cholesterol and LDL cholesterol suggest a low-grade inflammatory state that may be associated with the development of atherosclerosis and cardiovascular damage.
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Adulto Jovem , Proteína C-Reativa/análise , Doenças Cardiovasculares/etiologia , Hipotireoidismo/sangue , Tireotropina/sangue , Índice de Massa Corporal , Estudos Transversais , Equador , Aterosclerose , Hipotireoidismo/complicações , HDL-Colesterol/sangue , LDL-Colesterol/sangueRESUMO
Thyroid diseases are relatively common in women in the reproductive period. It is currently understood that clinically-evident thyroid disorders may impair ovulation and, consequently, fertility. However, to date it has not been proven that high serum levels of thyroid-stimulating hormone and/or positivity for antithyroid antibodies are associated to a reduction in fertility, mainly in the absence of altered thyroxine levels. The present comprehensive review aims to present current data on the association between subclinical hypothyroidism and/or thyroid autoimmunity and reproductive outcomes.
As doenças da tireoide são relativamente comuns em mulheres no período reprodutivo. Atualmente, entende-se que distúrbios da tireoide clinicamente evidentes podem prejudicar a ovulação e, consequentemente, a fertilidade. No entanto, não se provou até o presente que níveis séricos altos do hormônio estimulador da tireoide e/ou positividade para anticorpos antitireoidianos estão associados a uma redução na fertilidade, sobretudo na ausência de níveis alterados de tiroxina. Esta revisão narrativa tem como objetivo apresentar dados atuais sobre a associação entre hipotireoidismo subclínico e/ou autoimunidade tireoidiana e resultados reprodutivos.