Effects Of Subclinical Hyperthyroidism Research Articles

The Cardiovascular Effects of Subclinical Hyperthyroidism following Percutaneous Coronary Intervention

The Cardiovascular Effects of Subclinical Hyperthyroidism following Percutaneous Coronary Intervention

Effect of subclinical hyperthyroidism on osteoporosis: A meta-analysis of cohort studies.

The effect of subclinical hyperthyroidism (SH) on bone mineral density (BMD) remains unclear, as do the linking mechanisms. This review aims to investigate the relationship between SH and bone loss in terms of the gender-dependent effects of SH on BMD. The PUBMED, EMBASE, OVID, MEDLINE, SINOMED and COCHRANE LIBRARY databases (inception to August 12, 2019) were searched for cohort studies investigating the effects of SH on BMD. Eligible studies were subjected to qualitative and quantitative analysis using a random-effects model meta-analysis with the Cochrane systematic evaluation method. Twelve cohort studies involving 275,086 participants who were followed for 3 months to 13 years were included based on predefined inclusion and exclusion criteria. The results indicated that SH did not affect lumbar spine BMD in females or males. However, a significant reduction in femoral neck BMD was observed in females, but not in males. Further, there was a significant increase in hip fractures events in both females and males with SH. The present findings indicate that SH is significantly associated with hip fracture risk, and therefore, it is important to assess the risk of fractures in patients with SH. Future studies should focus on methods for accurately determining this risk in patients with SH and providing them with timely and efficient diagnosis and treatment.

Risk of Osteoporotic Fractures after Thyroid-stimulating Hormone Suppression Therapy in Patients with Thyroid Cancer.

BackgroundThe effects of subclinical hyperthyroidism on fracture risk induced by thyroid-stimulating hormone (TSH) suppression therapy in patients with thyroid cancer still remains controversial. We performed a meta-analysis and systematic review to evaluate the effects of TSH suppression therapy on osteoporotic fracture in patients with thyroid cancer.MethodsWe performed a systematic search to identify studies which included osteoporotic fractures (hip fracture and vertebral fracture) in patients on TSH suppression therapy for thyroid cancer. Main outcome measures were occurrence and risk of osteoporotic fractures including hip and vertebral fractures between patients and controls.ResultsA systematic search yielded a total of 8 studies appropriate for review which included osteoporotic fracture outcome in patients on TSH suppression therapy for thyroid cancer. Studies with larger number of subjects showed the higher risk of osteoporotic fracture in group with TSH suppression therapy, although studies with smaller sample size presented a similar risk of fracture with control group.ConclusionsAlthough studies were limited by small numbers, results suggested possible association between chronic TSH suppression therapy and the increased risk of osteoporotic fractures in patients with thyroid cancer.

Influence of Thyroid-stimulating Hormone Suppression Therapy on Bone Mineral Density in Patients with Differentiated Thyroid Cancer: A Meta-analysis.

BackgroundThe effects of subclinical hyperthyroidism on bone mineral density (BMD) induced by thyroid-stimulating hormone (TSH) suppression therapy in patients with differentiated thyroid cancer (DTC) remains unclear. We conducted a meta-analysis to determine the influence of TSH suppression therapy on BMD.MethodsWe performed a systematic search to identify studies which included BMD measurement of femoral neck, total hip or lumbar spine in patients on TSH suppression therapy for DTC. Main outcome measures were difference of BMD of femoral neck, total hip or lumbar spine measured by dual energy X-ray absorptiometry between patients and controls.ResultsA systematic search yielded a total of 11 published controlled cross-sectional studies (including about 571 patients and 836 controls). TSH suppression therapy was associated with the lower BMD of total hip (weighted mean difference [WMD], −0.023; 95% confidence interval [CI], −0.047 to 0.000; P=0.050) and spine (WMD, −0.041; 95% CI, −0.057 to −0.026; P<0.001) in postmenopausal women with DTC, while it was not associated with that in premenopausal women and men with DTC.ConclusionsAlthough the included studies were limited by small numbers, results suggested possible association between chronic TSH suppression therapy and the lower BMD of spine and total hip in postmenopausal women (but not in premenopausal women and men) with DTC. A large, well-designed study with long-term follow-up would provide further insight into the influence of TSH suppression therapy and loss of BMD.

Subclinical Hyperthyroidism and the Cardiovascular Disease.

Thyroid hormone excess has complex metabolic effects, particularly on the cardiovascular system. Treatment of these conditions is universally suggested by international guidelines. Subclinical hyperthyroidism, defined by reduced or suppressed TSH levels in the presence of normal free thyroxine and free triiodothyronine values, is common in the general population and progressively increases with aging, being as high as 15.4% in subjects more than 75 years old and more frequent in subjects with nodular goiter. Subclinical hyperthyroidism is often asymptomatic and the diagnosis is incidentally made during screening exams. However, this form of thyroid disorder has gained attention in the last years for its association with cardiovascular disease, in particular with atrial fibrillation. Less clear are the effects of subclinical hyperthyroidism on blood pressure, stroke, or heart failure. The decision to treat subclinical hyperthyroidism is made on the clinical judge, particularly in elderly patients and/or in the presence of comorbidities.

The Effect of Subclinical Maternal Thyroid Dysfunction and Autoimmunity on Intrauterine Growth Restriction: A Systematic Review and Meta-Analysis.

The objective of this study was to evaluate the association between maternal subclinical thyroid dysfunction and autoimmunity with the risk for intrauterine growth restriction (IUGR).Design is a systematic review and meta-analysis.A literature search was conducted using PubMed, Embase, and Cochrane database. A combination of 2 key words was used to search for the eligible studies: one indexed thyroid dysfunction or antithyroid antibodies; and the other one indexed the adverse neonatal outcomes of pregnancy, such as IUGR, small for gestational age, fetal growth restriction, or low birth weight.Two reviewers selected the studies, and eligible studies met the following criteria: prospective cohort studies or case control studies, studies of maternal thyroid dysfunction and positive antithyroid antibodies as the exposure of interest, and studies of IUGR or small for gestational age as the outcome of interest.Data were recorded, including data from maternal thyroid disorders and IUGR, and compared with a reference group.There were 22 individual data from the 13 cohort articles. Among these, 7 were focused on subclinical hypothyroidism (SCH), 4 on subclinical hyperthyroidism, 7 on positivity for thyroid peroxidase antibody (TPOAb), and 4 on isolated hypothyroxinemia. Meta-analysis showed that there was no effect of subclinical hyperthyroidism (odds ratio (OR) = 0.98; 95% confidence interval (CI), 0.40–2.41), TPOAb positivity (OR = 1.57; 95% CI, 0.77–3.18), or isolated hypothyroxinemia (OR = 1.05, 95% CI: 0.37–2.92) on IUGR. However, SCH is associated with IUGR (OR = 1.54; 95% CI, 1.06–2.25).SCH is associated with IUGR; however, subclinical hyperthyroidism, TPOAb positivity, or isolated hypothyroxinemia do not affect the risk of IUGR.

Subclinical Hyperthyroidism and Cardiovascular Risk

Subclinical hyperthyroidism (SHy), the mildest form of hyperthyroidism, is diagnosed in patients having a persistently low or undetectable serum concentration of thyroid-stimulating hormone (TSH) with normal free T4 and T3 concentrations. Although overt hyperthyroidism is associated with an increased risk of adverse cardiovascular outcomes, the cardiovascular risk of SHy is controversial. Multiple studies have demonstrated an increased risk of atrial fibrillation, especially in older individuals with TSH levels <0.1 mU/L. The effects of SHy on all-cause and cardiovascular mortality are not clear, but recent meta-analyses suggest a modest increase in mortality, with the risk increasing with age and associated with the lowest TSH levels. The long-term consequences of SHy in young- and middle-aged adults, and in those with TSH levels are mildly low, are uncertain. For these reasons, guidelines for treatment are based on patient age, the degree of TSH suppression, symptoms consistent with hyperthyroidism, and overall cardiovascular and osteoporotic fracture risks.

The Effect of Hyperthyroidism on Bone Mineral Density in Premenopausal Women

Background: The effects of subclinical hyperthyroidism and clinical hyperthyroidism on bone metabolism in premenopausal women are contradictory. Methods: Sixteen hyperthyroid (31.3±9.5 yrs), 23 subclinical hyperthyroid (33.7±7.3 yrs) and 20 healthy (31.7±8.1 yrs) premenopausal women were evaluated. Bone mineral density (BMD) was assessed by dual energy X-ray absorptiometry (DXA). Osteocalcin, total alkaline phosphatase (tALP), homocysteine, β-2 microglobulin, hsCRP and deoxypyridinoline (DPD) concentrations were assessed. Demographic and anthropometrical parameters; and osteoporotic risk factors were evaluated. Results: Serum calcium, tALP, osteocalcin, β-2 microglobulin and DPD were significantly different in hyperthyroid group. However there was no difference for any of the study parameters between control and subclinical hyperthyroid group. BMD was similar for all the three groups. Thyroid hormones were correlated with osteocalcin, β-2 microglobulin, tALP, lumbar vertebrae and femur BMD. Osteocalcine and tALP were significantly and negatively correlated with vertebral and femoral total BMD. Homocysteine was not different within groups but significantly correlated with tALP. Conclusions: There is limited and conflicting data about the effects of subclinical hyperthyroidism on bone turnover in premenopausal period. Despite we could not establish any difference for bone turnover markers between control group and subclinical hyperthyroid patients; with tight correlations between thyroid hormones; we can conclude that subclinical hyperthyroid patients are prone to osteoporosis even in premenopausal period.

Metabolic and cardiovascular risk in patients with a history of differentiated thyroid carcinoma: A case-controlled cohort study

Hyperthyroidism seems to increase metabolic and cardiovascular risk, while the effects of sub-clinical hyperthyroidism are controversial. We evaluated metabolic and cardiovascular parameters in differentiated thyroid carcinoma (DTC) patients with suppressed thyrotropin (TSH) due to levo-thyroxine (L-T4) therapy. We studied DTC patients and, as a control group, patients with a history of surgery for non-malignant thyroid pathology. Significantly higher insulin and lower HDL-cholesterol levels were recorded in DTC subjects. In both groups, insulin levels were significantly related with body mass index (BMI) but not with age or L-T4 dosage. In DTC patients, a significant negative correlation was seen between HDL-cholesterol and BMI or L-T4 dosage. In both groups, intima-media thickness (IMT) correlated positively with age, BMI, glucose levels and systolic blood pressure. In DTC patients, increased IMT was significantly correlated with glycated hemoglobin (HbA1c), cholesterol and triglycerides. In DTC patients, C-reactive protein correlated positively with insulin, insulin resistance, triglycerides and systolic blood pressure, and negatively with HDL-cholesterol. In both DTC and control subjects, fibrinogen correlated positively with age, BMI, increased IMT, HbA1c and systolic blood pressure. In DTC subjects, plasma fibrinogen concentrations correlated positively with insulin resistance, cholesterol and LDL-cholesterol, and negatively with TSH levels. Our data confirm that the favorable evolution of DTC can be impaired by a high incidence of abnormal metabolic and cardiovascular data that are, at least in part, related to L-T4 therapy. These findings underline the need for adequate L-T4 titration.

The effect of subclinical hyperthyroidism on ICSI outcome

The effect of subclinical hyperthyroidism on ICSI outcome

Lack of deleterious effect on bone mineral density of long-term thyroxine suppressive therapy for differentiated thyroid carcinoma

The effect of subclinical hyperthyroidism on bone mineral density is controversial and could be significant in patients with differentiated thyroid carcinoma who receive suppressive doses of levothyroxine (LT4). To ascertain whether prolonged treatment with LT4 to suppress thyrotropin had a deleterious effect on bone mineral density and/or calcium metabolism in patients thyroidectomized for differentiated thyroid cancer we have performed a cross-sectional study in a group of 88 women (mean +/- SD age: 51 +/- 12 years) treated with LT4 after near-total thyroidectomy and in a control group of 88 healthy women (51 +/- 11 years) matched for body mass index and menopausal status. We determined calcium metabolism parameters, bone turnover marker N-telopeptide and bone mass density by dual-energy X-ray absorptiometry. No differences were found between patients and controls in calcium metabolism parameters or N-telopeptide except for PTH, which was significantly increased in controls. No differences were found between groups in bone mineral density in femoral neck (0.971 +/- 0.148 gr/cm(2) vs 0.956 +/- 0.130 gr/cm(2) in patients and controls respectively, P = 0.5). In lumbar spine, bone mineral density values were lower in controls than in patients (1.058 +/- 0.329 gr/cm(2) vs 1.155 +/- 0.224 gr/cm(2) respectively, P < 0.05). When premenopausal (n = 44) and postmenopausal (n = 44) patients were compared with their respective controls, bone mineral density was similar both in femoral neck and lumbar spine. The proportion of women with normal bone mass density, osteopenia and osteoporosis in patient and control groups was similar in pre- and postmenopausal women. In conclusion, long-term suppressive LT4 treatment does not appear to affect skeletal integrity in women with differentiated thyroid carcinoma.

Exogenous Subclinical Hyperthyroidism During Adolescence: Effect on Peak Bone Mass

Chronic subclinical hyperthyroidism induced by suppressive doses of L-thyroxine (L-T4) therapy, so-called exogenous subclinical hyperthyroidism, may cause diminished bone mass in postmenopausal women. The effect of subclinical hyperthyroidism during childhood and adolescence on peak bone mass, however, has not been evaluated. To determine whether exogenous subclinical hyperthyroidism during adolescence, the period of critical bone mass acquisition, would reduce peak bone mass. Eighteen female adolescents and young adults with Hashimoto's thyroiditis and euthyroid goiter (aged 22.4 +/- 4.4 years) who had been treated with suppressive doses of L-T4, 127.5 +/- 23.7 microg/day, during adolescence (age at onset of subclinical hyperthyroidism, 14.2 +/- 1.5 years) for 6.3 +/- 3.4 years were enrolled in the study. Twenty-nine healthy female volunteers matched for age, weight, height and body mass index served as the controls. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry. BMD of the lumbar spine, radius, Ward's triangle and total body were comparable in the two groups. In contrast, BMD of the femoral neck, trochanter and shaft of patients was slightly higher than those of controls. There were no correlations between BMD values and clinical parameters. Exogenous subclinical hyperthyroidism during adolescence has no demonstrable detrimental effect on peak bone mass attainment.

203 Effects of subclinical hyperthyroidism on the heart: an ultrasonic tissue characterization study (backscatter)

203 Effects of subclinical hyperthyroidism on the heart: an ultrasonic tissue characterization study (backscatter)

Bone mineral density in well-differentiated thyroid cancer patients treated with suppressive thyroxine: a systematic overview of the literature.

The effects of subclinical hyperthyroidism on bone mineral density (BMD) induced by suppressive thyroxine therapy in patients with well-differentiated thyroid cancer (WDTC) remains unclear. An overview of the current literature was undertaken to evaluate studies to date. A systematic medline search yielded a total of 11 studies appropriate for review which included premenopausal women, postmenopausal women, and men on suppressive thyroxine post thyroidectomy for WDTC. Main outcome measures were bone mineral density and bone turnover markers. Although studies were limited by small numbers and varying degrees of control for confounding variables, results suggested no significant change in bone mineral density for premenopausal women or men. Findings for postmenopausal women remain unclear with two of the best controlled studies reporting opposing results. Further studies for this population are recommended to help guide clinical practice.

Effects of subclinical hyperthyroidism on renal handling of water and electrolytes in patients with nodular goiter

Evidence is beginning to accumulate that minor degrees of hyperthyroidism lead to adverse effects in various tissues, even though clinically the patients are euthyroid. To determine whether these anomalies in thyroid function have deleterious effects on renal function and electrolyte metabolism, the plasma concentrations of electrolytes, urea, and creatinine, the renal handling of water and sodium, and the urinary excretion of these substances were measured in patients with nodular goiter who were displaying stable subclinical hyperthyroidism. The studies were carried out before and after correcting the thyroid dysfunction. Restoration of euthyroidism did not modify any of the renal function parameters studied and did not cause changes in blood analyte levels. The data show that treatment of minor degrees of hyperthyroidism does not have any effects on renal function and electrolyte metabolism, and confirm the well-known capacity of the kidney to adjust its functions to changes induced by an abnormal secretion of thyroid hormones.