Alper Gurlek

Background: Vitamin D deficiency is a common global health problem and remains highly prevalent in Türkiye, where limited food fortification and heterogeneous clinical practices contribute to variability in testing and supplementation strategies. Aims: To provide Türkiye-specific best practice recommendations for defining clinically relevant serum 25-hydroxyvitamin D [25(OH)D] thresholds, identifying adult risk groups for targeted testing, and recommending evidence-based prevention, treatment, and monitoring approaches while minimizing under-treatment and inappropriate high-dose use. Methods: This national expert consensus document was developed by endocrinologists from across Türkiye using a structured, modified Delphi methodology. Draft statements informed by systematic literature reviews were rated via online surveys using a 9-point Likert scale, followed by two Delphi rounds and a face-to-face consensus meeting in İstanbul in October 2025. Results: Recommendations addressed sun exposure, laboratory assessment, screening, supplementation, treatment, and follow-up. Serum 25(OH)D <20 ng/mL was defined as deficiency and <12 ng/mL as severe deficiency, with a target range of 20–50 ng/mL. Routine population-wide screening was not recommended; instead, targeted testing in high-risk adults and symptom-driven biochemical evaluation were endorsed. Empiric supplementation was recommended for selected high-risk groups, with cholecalciferol as the preferred agent. Higher individualized doses were suggested in obesity or malabsorption, while loading regimens were reserved for specific clinical indications, such as severe deficiency or certain medical conditions that impair vitamin D metabolism. Reassessment of 25(OH)D at 8–12 weeks was recommended. Conclusion: These consensus-based recommendations provide a practical, context-specific framework for assessing, preventing, treating, and monitoring vitamin D deficiency in adults in Türkiye.

Background: Apoptosis inhibitor of macrophage (AIM) and monocyte chemotactic protein-1 (MCP-1) are molecules that cause migration of M1 macrophages to visceral adipocytes, which is the first step in development of metabolic syndrome. The aim of this study is to evaluate the status of AIM and MCP-1 in metabolic syndrome and to investigate their use as biomarkers. Methods: Forty metabolic syndrome patients and 40 healthy individuals were enrolled in the study. Serum AIM, MCP-1, and C-reactive protein (CRP) levels were measured by enzyme-linked immunosorbent assay. Results: AIM, MCP-1, and CRP levels were significantly higher in the metabolic syndrome group ( P < 0.01, P < 0.01, and P < 0.05, respectively). There was a positive correlation of serum AIM, MCP-1, and CRP levels with waist circumference ( r = 0.480, r = 0.663, and r = 0.418, respectively; P < 0.01). Receiver operating characteristic (ROC) curve analyses revealed AIM, MCP-1, and CRP cutoff points as 2383.7 ng/mL, 172.8 pg/mL, and 0.366 mg/dL, which could be used in the diagnosis of metabolic syndrome with highest sensitivity and specificity. In the logistic regression model, including age, AIM, CRP, and MCP-1 as covariates, having serum AIM and CRP levels above cutoffs were significant independent predictors for metabolic syndrome (odds ratios 13.8 and 21.3), whereas the serum MCP-1 level was not a significant independent predictor, although the odds ratio was 2.6 ( P = 0.193). Conclusions: These results suggest that AIM and MCP-1 may play a role in the pathogenesis of metabolic syndrome. AIM and CRP levels may be used as biomarkers in the diagnosis of metabolic syndrome. Although MCP-1 is not an independent predictor, its elevation in metabolic syndrome is noteworthy, which warrants further analyses in larger groups.

Anadolu Kardiyoloji Dergisi, Anadolu Kardiyol Derg, The Anatolian Journal of Cardiology, Anatol J Cardiol, Cardiology, Cardiovascular Medicine, Surgery, Pediatric Cardiology, Angiology

Background: In recent years, hemoglobin A1c (HbA1c) is accepted among the algorithms used for making diagnosis for diabetes and prediabetes since it does not require subjects to be prepared for giving a blood sample. The aim of this study is to assess the performance of HbA1c against fasting plasma glucose (FPG) and oral glucose tolerance test (OGTT) in detecting prediabetes and diabetes. Materials and Methods: A total of 315 subjects were included in this study. The success of HbA1c in distinguishing the three diagnostic classes was examined by three-way receiver operating characteristic (ROC) analysis. The best cut-off points for HbA1c were found for discriminating the three disease status. Results: The performance of HbA1c, measured by the volume under the ROC surface (VUS), is found to be statistically significant (VUS = 0.535, P < 0.001). The best cut-off points for discriminating between normal and prediabetes groups and between prediabetes and diabetes groups are c1 = 5.2% and c2 = 6.4% respectively. Conclusion: The performance of HbA1c in distinguishing between the prediabetes and diabetes groups was higher than its ability in distinguishing between healthy and prediabetes groups. This study provides enough information to understand what proportion of diabetes patients were skipped with the HbA1c especially when the test result is healthy or prediabetes. If a subject was diagnosed as healthy or prediabetes by HbA1c, it would be beneficial to verify the status of that subject by the gold standard test (OGTT and FPG).

Background and Aim: Prolactinoma is the most common type of functional pituitary tumor in adults. Giant prolactinomas are defined as tumors achieve a diameter >4 cm and often have very high serum prolactin level. In our previous study showed that endoscopic endonasal pituitary surgery is a very convenient procedure for the patient due to low morbidity and high efficiency. In this study we evaluated endoscopic endonasal pituitary surgery series in patients with prolactinoma. Methods: We, therefore present a retrospective analysis of the early results of 151 consecutive prolactinoma cases operated by the seniour author (MB) at Hacettepe University, Department of Neurosurgery over a period of 7 years. Results: A total of 151 patients, 81 (53.3%) female and 70 (46.7%) male, mean age 35.7±13.6 year (range 14–73 year), underwent endoscopic endonasal transspenoidal surgery for prolactin pituitary tumors. On the basis of MRI data, 21 patients (13.8%) had a microadenoma, 123 (80.9%) had a macroadenoma, and the remaining 8 (5.3%) had a giant adenoma. Cavernous sinus invasion was identified in 23 tumors by MRI, and confirmed by histology (n=15). Presenting symptoms included visual disturbance in 22 cases. Pathological diagnosis was atypical adenoma in 14 patients. Immediately after surgery, 34.6% patients went into remission. There were reports of postoperative four CSF leak and third menengitis ın our series. Fifty-five patients needed dopamine agonist treatment postoperatively. Conclusion: Endoscopic endonasal approach is a safe and effective procedure for the resection of prolactinoma, particularly for the ones which are resistant to dopamine agonists and atypical adenomas. We suggest that tumors with apoplexia, compression to the optic chiasma and invasion to the cavernous sinus are suitable for this type of surgical procedure before considering medical treatment.

Background and aim: Incidentally discovered adrenal masses (adrenal incidentalomas (AI)), generally 1 cm or more in diameter, are mostly benign and asymptomatic and are often considered as nonfunctional tumors. The aim of this study was to perform the imaging characteristics, endocrinologic screening and histologic diagnoses of adrenal incidentaloma cases encountered in our institute. Methods: This retrospective evaluation of patients with AI includes 543 cases between 2001 and 2013. Patients were 228 males and 315 females, aged between 18 and 105 years (median, 57 years). Results: Mass size (computed tomography measurement) ranged from 5 to 150 mm (median, 21 mm). Hormonal work-up demonstrated that 76.2% of the masses were nonsecretory, 11.4% were pheochromocytoma, 9.9% were defined as subclinical Cushing’s syndrome (SCS), 1.6% Cushing’s syndrome, 0.5% were hyperaldosteronism and 0.5% patient concomitant secretion of glucocorticoid, mineralocorticoid, androgen, and catecholamines. Adrenalectomy was performed in 108 patients with removal of 28 adrenocortical adenomas (26%), 15 pheochromocytoma (14%), 14 adrenocortical carcinomas (13%) and other less frequent tumor types. In patients with SCS; the rate of abnormalities was as follows: cortisol nonsuppressibility after 1 mg dexamethasone in 100%, above normal urinary free cortisol in 36.4%, and low ACTH in 28.6%. No significant difference was observed in the ages among patients with adrenocortical carcinoma and adrenocortical adenomas (48.7±10.7; vs 55.6±11.6 years; P=0.066). Patients with adenomas were significantly smaller than carcinomas (32±10 vs 54±35; P=0.037). The survival of patients with AI that were functional evaluated was higher than those that were not (respectively; median 149, 53 months). Conclusion: Based on these findings, an optimal diagnostic approach to an adrenal incidentaloma would consider the results of the initial biochemical and radiographic evaluations. Endocrine evaluation should be performed in all patients to identify silent states of hormone excess.

Background Hashimoto’s Thyroiditis (HT) is frequently isolated, but may also be associated with other autoimmune disorders. Autoimmune hypophysitis can result in growth hormone deficiency (GHD). Various prevalences of GHD have been reported in HT in several different ethnic populations. Aim The aim of this study was assessing the prevalence of GHD in Turkish population with HT. Materials and methods Two hundred twenty-seven (208 females and 19 males, mean age 40.1 ± 10.8 years, range 18–64 years) patients with euthyroid HT were included. Results All patients were euthyroid with or without T₄ treatment (median TSH 2.2 mIU/L, range 0.2–4.2 mIU/L; median FT₄ 15.6 pmol/L, range 12–22 pmol/L; and median FT₃ 4.5 pmol/L, range 3.0–6.2 pmol/L), and median TPO-Ab was 817 IU/mL (range 63 to >3,000). One hundred and thirty-six of them were using medications including l-thyroxine (59.9 %). Insulin-like growth factor-I (IGF-I) levels of 210 patients (92.5 %) were normal. Glucagon stimulation testing in 17 subjects revealed GHD (peak <3 mcg/L) in two subjects. We then performed insulin tolerance test (ITT) to both of them as the gold standard confirmatory test. One patient had no GH response to ITT, either. Our data reveal the prevalence of GHD (based on low IGF-I and ITT result) in this particular group of Turkish HT patients as 0.4 %. Conclusion We conclude that the isolated GHD is rarely observed in HT in our population. The prevalence of GHD is 0.4 % in this particular group of Turkish HT patients suggesting that routine investigation of GHD is not mandatory.

Adipose tissue secretes a variety of active biological substances, called adipocytokines, that act in an autocrine, paracrine, and endocrine manner. They have roles in appetite control, thermogenesis, and thyroid and reproductive functions. All these molecules may lead to local and generalized inflammation, mediating obesity-associated vascular disorders including hypertension, diabetes, atherosclerosis, and insulin resistance. Thyroid dysfunction is associated with changes in body weight, thermogenesis, and energy expenditure. The connections between cardiovascular risk factors such as dyslipidemia, impaired glucose tolerance, insulin resistance, atherosclerosis, and thyroid dysfunction have been reported in several studies. The adipocytokines serve as causative or protective factors in the development of these disorders in the states of thyroid dysfunction. Abnormal levels of adipocytokines (adiponectin (ADP), leptin, resistin, vaspin, and visfatin) in hypo- and hyperthyroidism have been reported with controversial results. This review aims to update the implication of novel adipokines ADP, vaspin, and visfatin in thyroid dysfunction.

Introduction: Chemerin is a novel adipokine that is correlated with adipocyte differentiation, glucose metabolism and inflammation, but its role remains to be elucidated in atherosclerosis particularly in diabetes and prediabetes. We aimed to investigate the relation of serum chemerin levels with markers of atherosclerosis as exemplified by pulse wave velocity (PWV), carotid intima media thickness (CIMT), and carotid plaque presence in these groups. Methods and materials: We included age, BMI, and gender matched 30 patients with type 2 DM, 19 patients with prediabetes, and 25 healthy individuals with normal glucose tolerance. Serum chemerin levels, lipid parameters, fasting glucose and insulin levels, homeostasis model assessment of insulin resistance (HOMA-IR) were assessed. PWV, CIMT, anthropometric measures, body fat percent, and epicardial fat thickness were recorded. Results: Serum chemerin levels were similar among groups (226.5±36.8 ng/ml in controls, 242.5±42.8 in prediabetes, 233.0±40.4 in diabetes, P=0.338), though glucose metabolism parameters including HOMA-IR were higher in patients with type 2 DM. PWV was higher in diabetes than in prediabetes and controls (P=0.039). Chemerin levels were positively correlated with BMI (Pr=0.425), total cholesterol (P=0.042, r=0.239), triglyceride (P=0.038, r=0.246), body fat percent (P=0.007, r=0.313) and left CIMT (P=0.032, r=0.249) in whole group. BMI and body fat percent were also correlated with chemerin in diabetic group whereas body fat percent and left CIMT remained to be correlated with chemerin in prediabetic group. Eleven patients in the diabetic group, two patients in the prediabetic group and three individuals in the control group had carotid plaque. Chemerin levels were comparable in patients with diabetes when grouped according to the presence of carotis plaque. Conclusion: Although chemerin is not correlated with atherosclerosis markers as measured by PWV and carotid plaque in diabetes and prediabetes, positive correlation with body fat percent in total group and positive correlation of CIMT and chemerin in prediabetes still arise an unanswered question about its role in atherosclerosis requiring further investigations.

Background and Aim: Prevalence of Hashimoto’s thyroiditis is increasing in Turkey. GH deficiency has been reported to associate with this disorder in several different ethnic population. The aim of this study was to evaluate GH deficiency in the population with Hashimoto’s thyroiditis. Materials and methods: Euthyroid Hashimoto’s thyroiditis patients, who admitted to the Department of Endocrinology and Metabolism of Hacettepe University, were included to the study. Demographic and laboratory data of patients were recorded. Results: One hundred ninety three patients with Hashimoto’s thyroiditis were evaluated (17 males, 176 females (8.8 vs 91.2%)). Mean age was 39.94±11.02 (min: 18 years, max: 64 years). There were no co-morbid conditions in any patients. One hundred and eleven of them were using medications containing L-thyroxine (57.5%). IGF1 levels of 179 patients (92.8%) were normal. Fourteen patients had low levels of IGF1. Glucagon stimulation testing in 14 subjects revealed GH deficiency (peak <3 μg/l) in only one subject. This subject had no response to insulin tolerance test either and she was put GH replacement therapy. Our data reveals the prevalence of GH deficiency in this particular group of Turkish Hashimoto’s thyroiditis patients was 0.5%. Conclusion: We conclude that isolated GH deficiency is rarely observed in Hashimoto’s thyroiditis patients. There were diverse outcomes of different studies about GH deficiency in Hashimoto’s patients from different ethnic backgrounds (0.4–5%). This preliminary study on this issue demonstrated that GH deficiency is 0.5% this particular group of Turkish Hashimoto’s thyroiditis patients.