Cuneyd Anil

Metabolic syndrome and its components are associated with increased thyroid volume and nodule prevalence in a mild-to-moderate iodine-deficient area

OBJECTIVE Metabolic syndrome (MetS) is a cluster of metabolic abnormalities with insulin resistance (IR) as a major component. It has been recently questioned whether MetS and its related components are associated with functional and morphological alterations of the thyroid gland. The aim of our study is to examine thyroid volume and nodule prevalence in a case-control study of patients with MetS in a mild-to-moderate iodine-deficient area. DESIGN Two hundred and seventy-eight patients with MetS were randomly matched for age, gender, and smoking habits with 261 subjects without MetS. Serum TSH, free tri-iodothyronine and thyroxine, and the level of IR, which was estimated by the homeostasis model assessment for IR, as well as other MetS parameters were evaluated. Thyroid ultrasonography was performed in all subjects. All subjects with thyroid nodules >1 cm were offered to undergo thyroid fine needle aspiration biopsy. RESULTS TSH was significantly positively correlated with the presence of MetS diagnosis. There was no association between free thyroid hormone levels and MetS and its related components. Mean thyroid volume was significantly higher in patients with MetS than in controls (17.5 + or - 5.5 vs 12.2 + or - 4.2 ml, P<0.0001). Also the percentage of patients with thyroid nodules was significantly higher in patients with MetS (50.4 vs 14.6%, P<0.0001). Subjects were also divided into two groups according to the presence of IR. The group of subjects with IR had increased thyroid volume and nodule formation. The odds ratio for the development of thyroid nodule in the presence of IR was 3.2. TSH as well as all MetS components were found to be independent predictors for thyroid volume increase. IR but not TSH was found to be correlated with thyroid nodule formation. Thyroid cancer was diagnosed in 3 out of 38 patients with MetS who agreed to have a biopsy (7.9%). None of the subjects in the control group was diagnosed to have thyroid cancer. CONCLUSIONS The results suggest that patients with MetS have significantly increased thyroid volume and nodule prevalence. Multivariate regression analysis model demonstrated that the presence of IR contributed substantially to this increased risk. Our data provide the first evidence that IR is an independent risk factor for nodule formation in an iodine-deficient environment.

Hashimoto's Thyroiditis Is Not Associated with Increased Risk of Thyroid Cancer in Patients with Thyroid Nodules: A Single-Center Prospective Study

BACKGROUND The risk of thyroid carcinoma in patients with thyroid nodules associated with Hashimotos thyroiditis (HT) is a debatable issue. The studies defining the true risk of thyroid malignancy are scanty and mainly depend on retrospective series. To eliminate inherent bias of retrospective studies, this prospective study was carried out to evaluate the true malignancy rate of unselected thyroid nodules in patients with HT who underwent fine-needle aspiration cytology (FNAC). METHODS These prospective data were gathered on all patients newly diagnosed with thyroid nodules who were sent for FNAC between May 2006 and August 2009. All patients were evaluated for the presence of HT diagnosis by measuring thyroid autoantibodies. If a patient had at least one positive thyroid autoantibody, then the patient was defined as HT with thyroid nodules. There were 164 patients (147 women and 17 men) with thyroid nodules associated with HT (HT group). There were 551 patients (432 women and 119 men) with thyroid nodules without HT (control group). All patients underwent FNAC and ultrasonography (US). RESULTS The malignancy rate was 1.0% in HT group (2 out of 191 nodules) and 2.7% in the control group (19 out of 713 nodules), a not significant (p = 0.19) difference. In the two cytologically malignant nodules in HT group and 19 in the control group, papillary thyroid carcinoma was diagnosed after thyroidectomy and histopathological examination. US features of nodule echogenicity, structure, margin, and Doppler flow were similar between the two groups. US features of microcalcification and absence of peripheral halo were more prominent in the nodules of the control group (p = 0.002 and p < 0.001, respectively). CONCLUSIONS On the basis of cytopathological criteria, thyroid nodules in patients with HT are no more likely to be malignant than in those without HT. Many of the US features of benign thyroid nodules are similar in patients with and patients without HT.

Impaired glucose metabolism is a risk factor for increased thyroid volume and nodule prevalence in a mild-to-moderate iodine deficient area

OBJECTIVE Insulin resistance (IR) is a key factor involved in the pathogenesis of impaired glucose metabolism. IR is associated with increased thyroid volume and nodule prevalence in patients with metabolic syndrome. Data on the association of thyroid morphology and abnormal glucose metabolism are limited. This prospective study was carried out to evaluate thyroid volume and nodule prevalence in patients with pre-diabetes and type 2 diabetes mellitus (DM) in a mild-to-moderate iodine deficient area. MATERIALS AND METHODS Data were gathered on all newly diagnosed patients with pre-diabetes and type 2 diabetes mellitus between May 2008 and February 2010. 156 patients with pre-diabetes and 123 patients with type 2 DM were randomly matched for age, gender, and smoking habits with 114 subjects with normal glucose metabolism. Serum thyroid-stimulating hormone (TSH) and thyroid ultrasonography was performed in all participants. RESULTS Mean TSH level in the diabetes group (1.9±0.9 mIU/L) was higher than in the control group (1.4±0.8 mIU/L) and the pre-diabetes group (1.5±0.8 mIU/L) (P<0.0001 for both). Mean thyroid volume was higher in the pre-diabetes (18.2±9.2mL) and diabetes (20.0±8.2mL) groups than in controls (11.4±3.8mL) (P<0.0001 for both). Percentage of patients with thyroid nodules was also higher in the pre-diabetes (51.3%) and diabetes groups (61.8%) than in controls (23.7%) (P<0.0001 for both). CONCLUSIONS The results suggest that patients with impaired glucose metabolism have significantly increased thyroid volume and nodule prevalence.

Radioactive Iodine in the Treatment of Type-2 Amiodarone-Induced Thyrotoxicosis

OBJECTIVE Amiodarone-induced thyrotoxicosis (AIT) is usually classified into two types: type 1, in which a high iodine content triggers the autonomous production of thyroid hormone; and type 2, in which destructive thyroiditis causes the release of preformed thyroid hormone. AIT is a difficult management problem that sometimes requires ablative thyroid therapy. The use of radioactive iodine (RAI) therapy in patients with type-1 AIT who had a 24-hour radioactive iodine uptake (RAIU) value of >10% has been previously reported. Despite its documented efficacy at usual doses (10-30 mCi) in patients with type-1 AIT, the efficacy of RAI in those with type-2 AIT has never been questioned, because type-2 patients usually have low RAIU. We thought that high adjusted-dose RAI might be an attractive alternative to thyroid gland ablation in patients with type-2 AIT. PATIENTS AND METHODS Four patients with type-2 AIT who required thyroid ablation were included in the study. These individuals were either poor candidates for surgery or had refused surgery. The size of the thyroid gland in all subjects was within normal limits, and each thyroid was characterized by a homogenous echotexture on ultrasonography, the absence of vascularity on Doppler sonography, a low (<4%) 24-hour RAIU value and the absence of thyroid autoantibodies-all of which are characteristic of type-2 AIT. RESULTS The patients were initially treated with thionamides and glucocorticoids. All patients except one achieved euthyroidism before RAI therapy. All four patients received one dose of RAI (range 29-80 mCi) and followed up for 12 months. No exacerbation of thyrotoxicosis was noted after RAI therapy. Hypothyroidism (in three patients) or euthyroidism (in one patient) was achieved in first six months. CONCLUSIONS In patients with type-2 AIT, RAI treatment may be the therapy of choice for thyroid gland ablation.

Effect of radioiodine therapy on thyroid nodule size and function in patients with toxic adenomas.

BackgroundAutonomously functioning toxic adenomas are a common cause of hyperthyroidism. Although 131I seems to be a good therapeutic option with little postablative hypothyroidism for these patients, only a small number of recent studies have objectively evaluated changes in nodule size by ultrasonography following radioiodine therapy. MethodsWe prospectively followed 39 patients with a mean age of 51.2 (35–75) years for 12 months and the patients who remained toxic thereafter, until euthyroidism was provided. Thyroid function tests, sonographic volumes were determined initially and 3, 6 and 12 months after treatment. Radioiodine doses of 3.7 MBq·g−1 thyroid tissue corrected to a 100% 24 h 131I uptake were given. Thirty patients received a single dose, two required two doses and three required three to five doses of 131I due to persistent thyrotoxicosis. Sonographic volumes of the diffuse parts of the glands decreased significantly by 18% from a mean±SD value of 50±27.6 ml to 41±27.4 ml by the end of the 12 months. A significant decrease (8.3%, P=0.002) was achieved in the first three months. Toxic adenomas decreased in size more efficiently (54%) from a mean of 26±24 ml to 12±10 ml during 12 months, but also most significantly (28.8%, P=0.003) in the first 3 months of the follow-up. Thirty of the patients (76.9%) became euthyroid at the end of 12 months of follow-up. Four patients (10.3%) became overtly hypothyroid during the follow-up. ConclusionSingle or multiple doses of radioiodine can successfully treat toxic adenomas with a low rate of hypothyroidism and considerable nodule-volume reduction.

Thyroid volume in patients with glucose metabolism disorders

OBJECTIVE Thyroid volume and the prevalence of thyroid nodules are higher in patients with insulin resistance. A relationship between thyroid volume and glucose metabolism disorders (GMD) has not as yet been clarified. The present retrospective study aimed to investigate the association between GMD and thyroid volume. SUBJECTS AND METHODS We investigated the data of 2,630 patients who were evaluated for thyroid biopsy in our hospital. The study population included 602 patients with GMD, 554 patients with diabetes mellitus (DM) and 1,474 patients with normal glucose metabolism as a control group. We obtained the levels of serum thyroid stimulating hormone (TSH) and the thyroid volumes of those patients retrospectively. RESULTS The median ages for the control group, GMD group and DM group were 55 (15-91) years, 60 (27-97) years, and 65 (27-91) years respectively and there was a statistically significant difference between the groups with regard to age and gender (p<0.001). Levels of TSH were similar in all groups. The median total thyroid volumes for patients with DM and GMD were significantly higher than that of the control group [22.5 (3-202) mL, 20.2 (4-190) mL, and 19.2 (3-168) mL respectively, p≤0.001 for all parameters]. Also the median total thyroid volume for patients with DM was significantly higher than that of the GMD group (p<0.001). According to the correlation analysis, thyroid volume was significantly correlated with age (r=0.92, p<0.001) and TSH (r=0.435, p<0.001). Age, gender, TSH levels, GMD and DM diagnosis were independently correlated with thyroid volume. CONCLUSION The thyroid gland is one of the target tissues of metabolic disorders. We reported a positive correlation between GMD/type 2 DM and thyroid volume. Further controlled, prospective, randomized studies on this subject are required to gain more information.

Performance of abdominal bioelectrical impedance analysis and comparison with other known parameters in predicting the metabolic syndrome.

Although obesity is a powerful risk factor for metabolic syndrome (MetS) it is not present in all obese individuals. Increased visceral adipose tissue is the hallmark of this syndrome. In this cross sectional survey we aimed to use abdominal bioelectrical impedance analysis to measure the visceral adipose tissue (VAT) and trunk fat percentages (TF%) in the study population, correlate these findings with traditional anthropometric measures and biochemical parameters of metabolic syndrome and estimate a cut-off value of visceral fat for development of MetS. A total of 285 subjects were enrolled. VAT and TF% were measured by the AB-140 device via abdominal bioelectrical impedance analysis. Fat% was measured by a body composition analyzer (TBF-300). VAT was significantly positively correlated with body mass index, waist circumference, TF%, HOMA IR, fat percentage, fasting plasma glucose and triglycerides. Strongest correlations were between VAT and TF%, VAT and device measured waist circumference and between VAT and manual waist circumference (r=0.95, r=0.93, r=0.92 respectively). Correlations of VAT and TF% with metabolic parameters were significant but weak. The mean VAT and TF% in MetS (+) groups were significantly higher than patients in MetS (-) groups in both sexes. The areas under the ROC curves were 0.730 (95% CI: 0.661-0.791) for female VAT and 0.702 (95% CI: 0.654-0.749) for male VAT in predicting MetS which were similar to the areas under ROC curves calculated for device and manually measured waist circumference, HOMA IR and TF% in predicting MetS (p>0.05 for all comparisons). The accuracy of VAT and TF% for predicting MetS was not sufficient. From our results we can deduce that the performance of abdominal BIA in predicting MetS is weak but could be used in the follow-up of patients with obesity and/or MetS. This has to be confirmed in future studies.

Hypothyroidism, new nodule formation and increase in nodule size in patients who have undergone hemithyroidectomy

Introduction The current medical literature has conflicting results about factors related to hypothyroidism and nodular recurrences during follow-up of hemithyroidectomized patients. We aimed to evaluate factors that may have a role in new nodule formation, hypothyroidism, increase in thyroid lobe and increase in nodule volumes in these patients with and without Hashimotos thyroiditis (HT), and with and without levothyroxine (LT4) use. Material and methods We enrolled 140 patients from five different hospitals in Ankara and evaluated their thyroid tests, autoantibody titre results and ultrasonographic findings longitudinally between two visits with a minimum 6-month interval. Results In patients with HT there was no significant difference between the two visits but in patients without HT, thyroid stimulating hormone (TSH) levels and nodule volume were higher, and free T4 levels were lower in the second visit. Similarly, in patients with LT4 treatment there was no difference in TSH, free T4 levels, or lobe or nodule size between the two visits, but the patients without LT4 had free T4 levels lower in the second visit. Regression analysis revealed a relationship between first visit TSH levels and hypothyroidism during follow-up. Conclusions Patients who have undergone hemithyroidectomy without LT4 treatment and without HT diagnosis should be followed up more carefully for thyroid tests, new nodule formation and increase in nodule size. The TSH levels at the beginning of the follow-up may be helpful to estimate hypothyroidism in hemithyroidectomized patients.

Do Statins Affect Thyroid Volume and Nodule Size in Patients with Hyperlipidemia in a Region with Mild-to-Moderate Iodine Deficiency? A Prospective Study

Objective: The objective of this study was to assess the antiproliferative pleiotropic effects of statins on thyroid function, volume, and nodularity. Subjects and Methods: One hundred and six hyperlipidemic patients were included in this prospective study. The 69 patients in the statin groups received atorvastatin (16 received 10 mg and 18 received 20 mg) or rosuvastatin (20 received 10 mg and 15 received 20 mg). The 37 patients in the control group, assessed as not requiring drugs, made only lifestyle changes. Upon admission and after 6 months, all patients were evaluated by ultrasonography as well as for lipid variables (total cholesterol, high- and low-density lipoprotein cholesterol, and triglycerides) and thyroid function and structure. Results: After 6 months, no differences in thyroid function, thyroid volume, the number of thyroid nodules, or nodule size were observed in the statin and control groups. In a subgroup analysis, total thyroid volume had decreased more in patients receiving 20 mg of rosuvastatin than that in the control group (p < 0.05). Maximum nodule size had decreased more in those receiving 10 mg of rosuvastatin (p < 0.05). Conclusions: Our results suggest an association between rosuvastatin treatment and smaller thyroid volume and maximum nodule diameter; this could be attributable to the antiproliferative effects of statin therapy on the thyroid.