Person: YOLDEMİR, AHMET TEVFİK
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YOLDEMİR
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AHMET TEVFİK
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Publication Metadata only Estrogen receptor gene polymorphisms in a group of postmenopausal Turkish women: association with bone mineral density(TAYLOR & FRANCIS LTD, 2012) YOLDEMİR, AHMET TEVFİK; Yavuz, D. G.; Yoldemir, T.; Ozaltun, K.; Erenus, M.Objective To evaluate the frequency of the estrogen receptor (ER) gene PvuII and XbaI polymorphisms and their associations with bone mineral density (BMD) in a group of postmenopausal Turkish women. Design A total of 125 healthy postmenopausal women and 125 premenopausal healthy young women as controls were included in the study. The PvuII and XbaI polymorphisms in the ER gene were studied by the polymerase chain reaction-restriction fragment length polymorphism method. The BMD of the lumbar vertebrae and femoral neck were measured by dual-energy X-ray absorptiometry. Results The frequencies of the ER alpha PVuII genotypes PP, Pp and pp were 20%, 54.4% and 25.6% in premenopausal and 24.8%, 44.8% and 30.4% in postmenopausal women, respectively. The frequencies of the ER XbaI genotypes XX, Xx, xx were 16.8%, 48.8% and 34.4% in premenopausal and 16.8%, 48% and 35.2% in postmenopausal women, respectively. There was no difference in the frequencies of ER gene polymorphisms between premenopausal and postmenopausal women. BMD measurements were not different between ER PvuII and XbaI genotypes in premenopausal and postmenopausal women. Conclusions ER gene PvuII and XbaI polymorphisms have no major influence on bone mineral density in our group of postmenopausal women.Publication Metadata only Vitamin D receptor gene polymorphisms in a group of postmenopausal Turkish women: association with bone mineral density(INFORMA HEALTHCARE, 2011) YOLDEMİR, AHMET TEVFİK; Yoldemir, T.; Yavuz, D. G.; Anik, G.; Verimli, N.; Erenus, M.Objective To determine the frequency of the vitamin D receptor (VDR) gene polymorphisms BsmI, ApaI, TaqI and FokI and their associations with bone mineral density (BMD) in postmenopausal Turkish women. Design One hundred and thirty healthy postmenopausal women and 130 premenopausal healthy women acting as controls were included in the study. The BsmI, FokI, ApaI and TaqI polymorphisms in the VDR gene were studied by polymerase chain reaction-restriction fragment length polymorphism method. The BMD of the lumbar vertebrae and femur neck were measured by dual-energy X-ray absorptiometry. Comparisons between the groups were performed using the paired t-test and ANOVA. chi(2) or contingency tables were used to analyze qualitative results. Results Genotypes BB, Bb and bb occurred in premenopausal women with frequencies of 16.92%, 50% and 33.08% and in postmenopausal women with frequencies of 16.92%, 56.15% and 26.92%, respectively. Genotypes FF, Ff, ff occurred in premenopausal women with frequencies of 47.69%, 42.31% and 10% and in postmenopausal women with frequencies of 50.77%, 42.31% and 6.92%, respectively. Genotypes AA, Aa, aa occurred in premenopausal women with frequencies of 23.85%, 56.15% and 20% and in postmenopausal women with frequencies of 26.15%, 46.15% and 27.70%, respectively. Genotypes TT, Tt and tt occurred in premenopausal women with frequencies of 37.69%, 45.38% and 16.92% and in postmenopausal women with frequencies of 39.23%, 45% and 15.38%, respectively. There was no difference in the frequencies of VDR gene polymorphisms between premenopausal and postmenopausal women. BMD measurements were not different between genotypes in premenopausal and postmenopausal women. Conclusions The VDR gene BsmI, FokI, ApaI and TaqI polymorphisms have no major influence on bone mineral density in our group of postmenopausal women.Publication Metadata only Effects of vitamin D supplementation on insulin sensitivity and androgen levels in vitamin-D-deficient polycystic ovary syndrome patients(WILEY, 2018) YOLDEMİR, AHMET TEVFİK; Karadag, Cihan; Yoldemir, Tevfik; Yavuz, Dilek GogasAimThe aim of this study was to identify the effects of vitamin D supplementation on insulin sensitivity and androgen levels in vitamin-D-deficient polycystic ovary syndrome (PCOS) patients. MethodsSixty-seven vitamin-D-deficient (25-hydroxyvitamin D [25(OH)D] levels below 20ng/mL) PCOS patients and 54 vitamin-D-deficient non-PCOS volunteer subjects matched for age and body mass index were enrolled to this prospective study. All participants were given 50000IU/week cholecalciferol orally for 8weeks and 1500IU/day for 4weeks. Insulin sensitivity was calculated with the Matsuda insulin sensitivity index (ISI) based on an oral glucose tolerance test. Matsuda ISI, gonadal hormones (estrogen, testosterone, androstenedione), and 25(OH)D levels were studied before and at the end of the 12th week of vitamin D load. ResultsAfter vitamin D supplementation, serum androstenedione levels had decreased significantly (P=0.007) and Matsuda ISI values had increased significantly (P=0.001) in the PCOS group but no significant changes were seen in those parameters in controls. We observed positive correlations between 25(OH)D levels and Matsuda ISI (r=0.307; P< 0.01), and negative correlations between 25(OH)D levels and total testosterone (r=-0.306; P< 0.01) and androstenedione (r=-0.275; P< 0.01) levels in the PCOS group. ConclusionVitamin D supplementation increased insulin sensitivity and decreased androgen levels in vitamin-D-deficient women with PCOS but did not have any effect in vitamin-D-deficient non-PCOS women. These results may indicate the possible role of vitamin D in the complex pathogenesis of PCOS.Publication Metadata only The association of osteopenia with levels of serum 25-hydroxyvitamin D and HOMA-IR values(TAYLOR & FRANCIS LTD, 2014) YOLDEMİR, AHMET TEVFİK; Yoldemir, T.; Yavuz, D. G.Objective To determine the association of osteopenia with levels of serum 25-hydroxyvitamin D and HOMA-IR values in postmenopausal women. Methods One hundred healthy postmenopausal women were included in a cross-sectional study. Venous blood was collected after an overnight fast and 25-hydroxyvitamin D, glucose and insulin levels were measured. HOMA-IR was calculated. Bone mineral density was measured with a dual X-ray absorptiometer. Results There was no difference in serum 25-hydroxyvitamin D levels and HOMA-IR values between the two groups. A weak positive correlation between serum 25-hydroxyvitamin D levels and osteopenia was detected. Insulin resistance had a weak negative association with osteopenia. Conclusions The correlations between osteopenia and serum 25-hydroxyvitamin D levels and HOMA-IR values were weak among early postmenopausal women.Publication Metadata only The evaluation of endothelial function and structure in hirsute patients in reproductive age(ELSEVIER SCIENCE BV, 2016) YOLDEMİR, AHMET TEVFİK; Atasayan, Kemal; Yoldemir, Tevfik; Ramoglu, Sedef; Yavuz, Dilek GogasObjective: To evaluate the endothelial function and structure in patients with hirsutism in reproductive age. Study design: The study was conducted on 69 consecutive women admitted with complaints of hirsutism and 63 voluntary healthy women, as controls. A total of 132 subjects who applied to the Gynecology and Infertility Outpatient Clinics were included. Participants with modified Ferriman Gallway (mFG) score over 8 were considered to be hirsute. The demographic, metabolic, hormonal characteristics, risk factors of cardiovascular disease, CIMT (carotis intima media thickness) and FMD (flow-mediated dilatation) were compared between hirsute women and those in the control group. A prospective case-control study was performed. Results: There was no statistically significant difference in CIMT (0,50 0,08 vs 0,52 0,08, p = 038) and FMD (10,80 6,83 vs 9,57 6,52, p = 0.34) values between the study and control groups, respectively. There was no statistically significant correleation between CIMT and FMD values with age, body mass index (BMI), waist circumference, hip circumference, waist/hip ratio, CRP (C-reactive protein), total cholesterol, LDL (low density lipoprotein), HDL (high density lipoprotein), total testosteron, FAI (free androjen index), androstenedion, SHBG (sex hormone binding globuline), DHEA-S, hirsutism score, sistolic blood pressure, diastolic blood pressure, HOMA-IR (homeostatic model of assesment insuline resistance) value. Conclusion: The effect of the presence of hirsutism on either CIMT and FMD values, among young patients was not significant. Since endothelial dysfunction might became evident after a long period of physiopathological process, our findings obtained from younger patients may not really show the impact of hirsutism on endothelial function in short term. (C) 2016 Elsevier Ireland Ltd. All rights reserved.Publication Metadata only Association of serum paraoxonase concentration with serum lipid levels and bone mineral density measurements in early postmenopausal women(TAYLOR & FRANCIS LTD, 2015) YOLDEMİR, AHMET TEVFİK; Yoldemir, T.; Yavuz, D. G.Objective To determine the association of serum paraoxonase concentration with serum lipid levels and bone mineral density in early postmenopausal Turkish women. Design One hundred healthy postmenopausal women were included in a cross-sectional study in a University hospital clinic. Blood was drawn from women who had bone mineral density (BMD) measurements during routine visits. BMD of the lumbar vertebrae was measured by dual-energy X-ray absorptiometry. The serum paraoxonase concentration and serum lipid levels were measured. Women were divided into two groups: those with normal lumbar vertebrae BMD and those with osteopenic lumbar vertebrae. Serum paraoxonase concentration was compared between the groups. The correlation between serum paraoxonase concentration and bone mass parameters was performed using Pearson's test. Results The paraoxonase concentration in the osteopenic group was significantly lower than in the group with normal lumbar vertebrae BMD. The paraoxonase concentration was moderately correlated with total cholesterol, low density lipoprotein cholesterol and triglyceride levels among early postmenopausal Turkish women. Conclusions Early postmenopausal women with osteopenic lumbar vertebrae have significantly lower paraoxonase concentration than those with normal lumbar vertebrae BMD. Further studies are needed to clarify the associations between the osteoporosis risk factors and paraoxonase concentration during late postmenopausal years.Publication Metadata only Determinants of low bone mineral density in premenopausal polycystic ovary syndrome patients(TAYLOR & FRANCIS LTD, 2017) YOLDEMİR, AHMET TEVFİK; Karadag, Cihan; Yoldemir, Tevfik; Yavuz, Dilek GogasObjective: The aim of this study was to evaluate the bone mineral density (BMD) values and to determine the associations between BMD and insulin sensitivity, hyperandrogenemia, body mass index (BMI), and sex hormones in premenopausal polycystic ovary syndrome (PCOS) patients. Methods: A hundred and three women with PCOS and sixty age- and BMI-matched healthy control women were enrolled to this cross-sectional study. Serum androgen and estradiol (E2) levels were measured. Homeostasis model assessment of insulin resistance (HOMA-IR) and MATSUDA insulin sensitivity index (ISI) were calculated. BMD was measured with a dual X-ray absorptiometer. Results: Lumbar BMD (LBMD) and femoral neck BMD (FnBMD) values were significantly lower in PCOS group than controls [(p<0.01) and (p<0.01)]. In PCOS group, hyperandrogenemic women had higher LBMD and FnBMD values than normoandrogenemic PCOS patients [(p<0.01) and (p<0.01)]. In PCOS group, LBMD was significantly correlated with HOMA-IR (r=0.617; p<0.01), MATSUDA ISI (r=-0.665; p<0.01), serum E2 (r=0.488; p<0.01), total testosterone (r=0.436; p<0.01), and androstenedione (r=0.337; p<0.01) levels. Similar correlations observed for FnBMD. Conclusions: Despite the positive effects of hyperandrogenemia and hyperinsulinemia, PCOS patients have lower bone mineral density due to hypoestrogenism. Insulin resistance, BMI, estrogen, and androgen levels are the determinants of BMD in PCOS.Publication Metadata only Does cardiovascular risk vary according to the criteria for a diagnosis of polycystic ovary syndrome?(WILEY, 2017) YOLDEMİR, AHMET TEVFİK; Ramoglu, Sedef; Yoldemir, Tevfik; Atasayan, Kemal; Yavuz, Dilek GogasAimThe risk of cardiovascular disease is higher in women with polycystic ovary syndrome (PCOS) compared to healthy individuals. Chronic inflammation, insulin resistance, hyperandrogenemia, hyperlipidemia and increased oxidative stress are known to have a role in the formation of atherosclerosis and cardiovascular disease. The aim of our study was to evaluate if cardiovascular risk varied according to different PCOS criteria, using carotid intima-media thickness (CIMT), which is an important marker of major cardiovascular events in the later stages of life. MethodsThe study group included 52 women aged 18-35 diagnosed with PCOS, and the control group comprised 45 age-matched healthy women. Body mass index, CIMT, fasting serum glucose and insulin levels and hormonal and lipid profiles were compared between the groups. ResultsThere was no significant difference in CIMT levels between the groups. The CIMT levels in the PCOS group did not differ whether hyperandrogenism, polycystic ovary-like appearance on ultrasound or oligo/anovulation status were present or not. Furthermore, when all cases were divided into subgroups according to BMI values, the CIMT values were similar between the groups. ConclusionBecause PCOS and atherosclerosis both have a complex nature, it is likely that the evaluation of CIMT alone may not be sufficient to determine endothelial dysfunction in a reproductive age group.Publication Metadata only Thyroid disease in the perimenopause and postmenopause period(TAYLOR & FRANCIS LTD, 2018) YOLDEMİR, AHMET TEVFİK; Uygur, M. M.; Yoldemir, T.; Yavuz, D. G.The interpretation of thyroid function tests should be cautiously made during the perimenopause and postmenopause period bearing in mind that physiologic changes do exist in this group of women in terms of secretion and metabolism of thyrotropin and thyroid hormones. Moreover the incidence of thyroid disorders increases in postmenopausal and elderly women. There is no consensus for screening postmenopausal women even though there is well-known evidence about the effect of thyroid status on cognitive function, cardiovascular risk, bone turnover, and longevity. The diagnosis of any thyroid disorder is challenging in these patients because the symptoms are more subtle and attributed to menopausal symptoms. Management requires more attention in this population than that of younger groups, because high doses of L-thyroxine can lead to cardiac complications and increased bone turnover. Furthermore radio-iodine is preferred in treatment of hyperthyroidism in older patients. The risk of nodular thyroid disease and thyroid cancers increases in this group. Although the diagnostic approach is the same as for young patients, the risk of surgery is high and disease prognosis is worse. Women with any form of thyroid disease should be treated according to the current guidelines. Decision for menopausal hormonal therapy should be individualized regardless of the concomitant presence of thyroid disorders.