Alptekin Gursoy

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.

Prevalence and prediction of malignancy in cytologically indeterminate thyroid nodules

Objective Controversy surrounds the evaluation of nodules with indeterminate cytology results. Malignancy rates in these nodules are not low. We examined the malignancy rates in nodules that showed follicular neoplasm or atypical cells on cytology and attempted to predict malignancy based on ultrasonographic features.

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.

The analgesic efficacy of lidocaine/prilocaine (EMLA) cream during fine‐needle aspiration biopsy of thyroid nodules

Objective  Pain is one of the few drawbacks of fine‐needle aspiration biopsy (FNAB) in patients with nodular thyroid disease (NTD). Lidocaine/prilocaine cream, an eutectic mixture of local anaesthetics (EMLA), is a frequently used topical anaesthetic. Despite its well‐documented efficacy for the relief of pain associated with other cutaneous procedures that involve needle insertion, the analgesic role of EMLA has not been previously reported in patients with NTD who are undergoing FNAB. The aim of this study was to determine the analgesic efficacy of EMLA for FNAB‐associated pain in patients with NTD.

Evaluation of brain natriuretic peptide levels in hyperthyroidism and hypothyroidism.

BACKGROUND Brain natriuretic peptide (BNP) is secreted from the ventricular myocardium in response to volume expansion and pressure overload. Serum BNP levels are also affected by thyroid function status, which was mostly related to a direct stimulatory effect of thyroid hormones on the secretion of BNP. Although the diagnostic value of BNP in heart failure is undisputed, its value in the presence of the thyroid dysfunction has been recently questioned. The aim of this study was to evaluate the influence of thyroid dysfunction on BNP levels. METHODS Evaluation of 18 overt and 47 subclinical hyperthyroid patients together with 39 subclinical and 13 overt hypothyroid patients was carried out in a cross-sectional study. Thirty-three age-, sex- and body mass index (BMI)-matched control subjects were also included. RESULTS BNP levels were more than five times higher in hyperthyroid than euthyroid control subjects (P < 0.001). BNP levels were also higher in subclinical hyperthyroidism than euthyroid control subjects (P = 0.09). Correlation analysis revealed that free T4 and free T3 concentrations were associated with high serum BNP levels. The BNP level in patients with subclinical or overt hypothyroidism was similar to that of the controls. CONCLUSION The current study provides additional insight into the diagnostic value of BNP in the presence of coexistent thyroid dysfunction and demonstrates important independent effects of thyroid hormones upon BNP plasma concentrations.

Vitamin D receptor gene polymorphism and osteoporosis in the Turkish population.

Osteoporosis is one of the most important medical problems facing the aging population. It is defined as a decrease in the bone mass leading to an unacceptably high risk of fractures. Osteoporosis is a multifactorial disease. It is well established that genetic factors are involved in the pathogenesis of osteoporosis. Polymorphism of the vitamin D receptor (VDR) gene has been reported to play a major role in variations for genetic regulation of bone mass. Its role within various ethnic populations is not clear. The purpose of this project was to determine the frequencies of VDR genotypes in Turkey. Three polymorphisms of the VDR gene were analyzed using the polymerase chain reaction-restriction fragment length polymorphism technique. The sample for our study was comprised of postmenopausal women in Turkey, 100 of whom were diagnosed with osteoporosis. They were compared with 146 healthy controls. BsmI genotype frequencies in Turks resemble Caucasians rather than Asians, and Taq genotype frequencies in Turks neither resemble Caucasians nor Asians. The genotype frequencies of VDR were not statistically different between patients with osteoporosis and the control group. Among VDR haplotypes, bbAATT and bbTtAa are more frequent in the osteoporosis group than the control group.

Postprandial lipemia as a risk factor for cardiovascular disease in patients with hypothyroidism

Postprandial lipoprotein metabolism is suggested to play a role in the pathogenesis of atherosclerosis. In this study, we investigated postprandial lipemia and its relationship to cardiovascular risk factors in patients with overt and subclinical hypothyroidism. Twentynine female patients with TSH levels greater than 5 μIU/mL and 12 euthyroid control female subjects were included in the study. Fifteen patients had subclinical hypothyroidism and 14 had overt hypothyroidism. All subjects underwent an oral lipid tolerance test. If triglyceride levels increased by 80% or more, subjects were considered postprandial lipemia positive. Control, overt hypothyroid, and subclinical hypothyroid groups were not statistically different with respect to anthropometric measurements, fasting blood C-reactive protein, uric acid, homocysteine, glucose, insulin, lipoprotein (a), apolipoprotein B levels, and homeostasis model assessment index. Fasting triglyceride levels correlated positively with TSH levels. Postprandial lipemia frequency was higher in overt hypothyroid subjects than in the control group. The subclinical hypothyroid group did not differ from the hypothyroid group with respect to postprandial lipemia frequency. In subjects with TSH levels higher than 5 μIU/mL, PPL risk was increased sevenfold. The results of this study show that postprandial triglyceride metabolism is affected in hypothyroidism.

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.

Mean platelet volume in patients with polycystic ovary disease

Polycystic ovary syndrome (PCOS) is a frequently encountered clinical condition characterized by chronic anovulation and hyperandrogenism. There are many reports pointing to the causal links between PCOS and cardiovascular disease (CVD). Although the level of risk for CVD remains uncertain in PCOS, there is substantial evidence that insulin resistance, obesity, dyslipidemia, hypertension, hypercoagulable state, and markers of abnormal vascular function possibly contribute to increased CVD risk [1, 2]. Platelets play a crucial role in the pathogenesis of thrombotic diseases. Circulating platelets are heterogeneous in size, density, and reactivity. The mean platelet volume (MPV), the accurate measure of platelet size, is considered a marker and determinant of platelet function since larger platelets are hemostatically more reactive than platelets of normal size, increasing the propensity to thrombosis [3]. Elevated MPV levels have been shown to be an independent risk factor for CVD [4, 5]. We investigated MPV in patients with PCOS alongside a comparable group of healthy control subjects. Eighty-five newly diagnosed PCOS patients who have no propensity to thrombotic or bleeding disorder and 81 ageand BMI (body mass index)matched regularly menstruating healthy non-hirsute women as the controls participated in this study. Demographic details of subjects are presented in Table I. All MPV measurements were performed on automated blood counter Cell-Dyn 4000 (Abbott Diagnostics, Santa Clara, CA, USA). The other parameters measured in fasting blood sample were glucose, insulin, total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride, free testosterone and total testosterone, and estrogen. Glucose values obtained at 0, 30, 60, 90, and 120 minutes after a 75 g oral glucose tolerance test was also measured. Each subject’s level of insulin resistance was estimated based on the homeostasis model assessment insulin resistance (HOMA-IR) index. Clinical and laboratory features of patients with PCOS and control subjects are depicted in Table I. The MPV was significantly higher in patients with PCOS (8.5 1.4 fl) than control subjects (7.8 0.9 fl) (p1⁄4 0.002). There was no statistically significant difference regarding platelet absolute count in patients with PCOS (264 51 10/L) and control subjects (257 48 10/L). HOMA-IR index was significantly higher in patients with PCOS than control subjects (3.0 3.1 vs. 2.0 0.8, p1⁄4 0.02). We did not observe any significant correlation between MPV and age, BMI, HOMAIR, lipid parameters, and levels of estrogen, free and total testosterone in patients with PCOS. There was also no correlation between MPV and glucose values obtained at 0, 30, 60, 90, and 120 minutes after a 75 g oral glucose tolerance test. Although direct evidence for increased thrombotic risk is still lacking in patients with PCOS, increased propensity to thrombosis is suggested