VITAMIN DEFICIENCY AND INSULIN RESISTANCE IN NONDIABETIC OBESE PATIENTS

OBJECTIVE

Obese people may have nutritional deficiencies, although they are exposed to excessive food intake. We aim to assess relationship of vitamin D, B12, and folic acid levels and dietary vitamin intake and insulin resistance in obese people.

DESIGN

This case-control study was performed at the obesity outpatient clinics between March 2014 and April 2015.

SUBJECTS AND METHODS

We included 304 non-diabetic obese subjects in patient group and 150 normal weight individuals in control group. Patients were questioned in detail about their food intake.

RESULTS

Mean age of obese patients was 37.3±10.1 years, the mean duration of obesity was 7.9±5.4 years, and the percentage of female patients was 65.8%. Mean vitamin D, B12, and folic acid levels were significantly lower in patients than in controls. Vitamin D deficiency (<20 ng/mL) in 69.7%, vitamin B12 deficiency (<200 pg/mL) in 13.5%, and folic acid deficiency (<4 ng/mL) was found in 14.2% of the patients. BMI negatively correlated with vitamin D, B12, and folic acid levels. B12 levels negatively correlated with duration of obesity. Insulin resistance was found in 55.9% of patients and HOMA-IR levels negatively correlated with vitamin D and B12 levels. While dietary vitamin D and folic acid intakes were inadequate in all of patients, only 28.3% of patients had inadequate vitamin B12 intake. There was no relation between vitamin levels and dietary vitamin intakes.

CONCLUSIONS

The study reveals that vitamin D, B12, and folic acid levels were low and poor vitamin D and B12 status were associated with insulin resistance in nondiabetic obese patients.

Vitamin D receptor gene ApaI, TaqI, FokI and BsmI polymorphisms in a group of Turkish patients with Hashimoto's thyroiditis

AIM

Previous studies have suggested an influence of vitamin D receptor polymorphisms on the development of autoimmune thyroid disease in different ethnic populations. We aimed to investigate the distribution of vitamin D receptor (VDR) alleles in a group of Turkish patients with Hashimoto's thyroiditis (HT).

METHODS

One hundred and eleven patients (male/female: 5/106, 47.9±12.8 years) and 159 healthy controls (male/female: 21/138, 30.5±6.3 yrs) were included in the study. VDR gene FokI, BsmI, ApaI TaqI polymorphisms were examined using a polymerase chain reaction (PCR) -based restriction analysis. Serum levels of (thyroid-stimulating hormone) TSH, anti-thyroid peroxidase and anti-thyroglobulin levels were determined.

RESULTS

The VDR TaqI "TT" (59.5% in patients vs. 27.6% in controls; 95% confidence interval [CI]: 0.14-0.46) and FokI 'FF' genotypes (67.6% in patients vs. 44.6% in controls; 95% CI: 0.46-0.81) occurred more frequently in patients, while VDR "Tt" (56.6% in patients vs. 32.4% in controls 95% CI: 1.22-2.14) and "Ff" genotypes (25.2% in patients vs. 49.1% in controls 95% CI: 1.27-2.18) were more common in controls. There were no differences in the genotype frequencies of the ApaI and BsmI polymorphisms in cases and controls. The most common genotypes were "bbAaTTFF" in the thyroiditis group (12.6% patients vs. 5.6% in controls, P>0.05) and "BbAaTtFf" in the control group (6.3% patients vs. 22.2% in controls, P=0.002).

CONCLUSION

VDR gene TaqI TT and FokI FF genotypes are associated with increased risk of HT disease in our group of Turkish patients. BbAaTtFf genotype seems to be protective for HT disease in our population.

Association of metabolic syndrome parameters with TT3 and FT3/FT4 ratio in obese Turkish population

BACKGROUND

Obesity and metabolic syndrome are major health problems worldwide, including Turkey. Recent studies have shown an association between thyroid function tests and metabolic syndrome parameters. In this study, we aimed to determine the frequency of metabolic syndrome in an obese Turkish population and the relationship between metabolic syndrome and thyroid functions.

MATERIALS AND METHOD

We recruited 211 patients (187 females/24 males; mean age, 39.7±11.7 years) with body mass index (BMI) >30 kg/m(2) and no other hormonal pathology that could cause obesity. Anthropometric evaluation was followed by measurement of fasting blood glucose (FBG), insulin, total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), thyroid-stimulating hormone (TSH), total triiodothyronine (TT3), total thyroxine (TT4), free T3 (FT3), and free T4 (FT4). Metabolic syndrome was defined according to the 2005 revision of the National Cholesterol Education Program Adult Panel III (NCEP ATP III) criteria. Insulin resistance was calculated from homeostasis model assessment of insulin resistance (HOMA-IR) formula. The TSH cutoff value was set at 2.5 mU/L.

RESULTS

Metabolic syndrome was diagnosed in 122 patients (58%). Metabolic syndrome positive patients had significantly higher FBG, triglycerides, FT4, systolic (SBP) and diastolic blood pressure (DBP), and statistically lower HDL-C and FT3/FT4 ratio than metabolic syndrome negative patients. TSH decreased with age and was not related with any metabolic syndrome parameters. The FT3/FT4 ratio negatively correlated with FBG, triglycerides, SBP, and DBP (P=0.003, r=-38; P=0.02, r=-0.28; P=0.005, r=-0.35; and P=0.007, r=-0.34, respectively); TT3 positively correlated with HOMA-IR (P=0.006, r=0.40), FBG (P=0.009, r=0.38), and waist circumference (P=0.02, r=0.34).

CONCLUSION

Metabolic syndrome frequency was increased in our study population compared to the general population. Metabolic syndrome parameters (except HDL) correlated with TT3, FT4, and the FT3/FT4 ratio. FT4 levels were associated with obesity and metabolic syndrome independently of insulin resistance, whereas TT3 levels were associated with both insulin resistance and metabolic syndrome. This relationship can be explained by compensatory effects of TT3, and probably FT4, on energy expenditure and thermogenesis in obese people.

High prevalence of TSHR/Gsα mutation-negative clonal hot thyroid nodules (HNs) in a Turkish cohort

Whereas the majority of hot thyroid nodules are caused by somatic TSH-receptor mutations, the percentage of TSH-receptor mutation negative clonal hot nodules (HN) and thus the percentage of hot nodules likely caused by other somatic mutations are still debated. This is especially the case for toxic multinodular goiter (TMNG). 35 HNs [12 solitary hot nodules (SHN), 23 TMNG] were screened for somatic TSHR mutations in the exons 9 and 10 and for Gsα mutations in the exons 7 and 8 using DGGE. Determination of X-chromosome inactivation was used for clonality analysis. Overall TSHR mutations were detected in 14 out of 35 (40%) HNs. A nonrandom X-chromosome inactivation pattern was detected in 18 out of 25 (72%) HNs suggesting a clonal origin. Of 15 TSHR or Gsα mutation negative cases 13 (86.6%) showed nonrandom X-chromosome inactivation, indicating clonal origin. The frequency of activating TSHR and/or Gsα mutations was higher in SHNs (9 of 12) than in TMNGs (6 of 23). There was no significant difference for the incidence of clonality for HNs between TMNGs or SHNs (p: 0.6396). Activating TSHR and/or Gsα mutations were more frequent in SHNs than in TMNG. However, the frequency of clonality is similar for SHN and TMNG and there is no significant difference for the presence or absence of TSHR and/or Gsα mutations of clonal or polyclonal HNs. The high percentage of clonal mutation-negative HNs in SHN and TMNG suggests alternative molecular aberrations leading to the development of TSHR mutation negative nodules.

Effect of vitamin D deficiency and replacement on endothelial function in asymptomatic subjects

CONTEXT

Vitamin D receptors are present in many tissues. Hypovitaminosis D is considered to be a risk factor for atherosclerosis.

OBJECTIVE

This study explores the effects of vitamin D replacement on insulin sensitivity, endothelial function, inflammation, oxidative stress, and leptin in vitamin D-deficient subjects.

DESIGN, SETTING, AND PATIENTS

Twenty-three asymptomatic vitamin D-deficient subjects with 25-hydroxyvitamin D [25(OH)D] levels below 25 nmol/liter were compared with a control group that had a mean 25(OH)D level of 75 nmol/liter. The vitamin D-deficient group received 300,000 IU im monthly for 3 months. The following parameters were evaluated before and after treatment: vitamin D metabolites, leptin, endothelial function by brachial artery flow mediated dilatation (FMD), insulin sensitivity index based on oral glucose tolerance test, and lipid peroxidation as measures of thiobarbituric acid reactive substances (TBARS).

RESULTS

FMD measurements were significantly lower in 25(OH)D-deficient subjects than controls (P = 0.001) and improved after replacement therapy (P = 0.002). Posttreatment values of TBARS were significantly lower than pretreatment levels (P < 0.001). A positive correlation between FMD and 25(OH)D (r = 0.45; P = 0.001) and a negative correlation between FMD and TBARS (r = -0.28; P < 0.05) were observed. There was a significant increase in leptin levels after therapy, and the leptin levels were positively correlated with 25(OH)D levels (r = 0.45; P < 0.05).

CONCLUSIONS

This study shows that 25(OH)D deficiency is associated with endothelial dysfunction and increased lipid peroxidation. Replacement of vitamin D has favorable effects on endothelial function. Vitamin D deficiency can be seen as an independent risk factor of atherosclerosis. Hypovitaminosis D-associated endothelial dysfunction may predispose to higher rates of cardiovascular disease in the winter.

Melatonin ameliorates methionine- and choline-deficient diet-induced nonalcoholic steatohepatitis in rats

Nonalcoholic steatohepatitis (NASH) may progress to advanced fibrosis and cirrhosis. Mainly, oxidative stress and excessive hepatocyte apoptosis are implicated in the pathogenesis of progressive NASH. Melatonin is not only a powerful antioxidant but also an anti-inflammatory and anti-apoptotic agent. We aimed to evaluate the effects of melatonin on methionine- and choline-deficient diet (MCDD)-induced NASH in rats. Thirty-two male Wistar rats were divided into four groups. Two groups were fed with MCDD while the other two groups were fed a control diet, pair-fed. One of the MCDD groups and one of the control diet groups were administered melatonin 50 mg/kg/day intraperitoneally, and the controls were given a vehicle. After 1 month the liver tissue oxidative stress markers, proinflammatory cytokines and hepatocyte apoptosis were studied by commercially available kits. For grading and staging histological lesions, Brunt et al.'s system was used. Melatonin decreased oxidative stress, proinflammatory cytokines and hepatocyte apoptosis. The drug ameliorated the grade of NASH. The present study suggests that melatonin functions as a potent antioxidant, anti-inflammatory and antiapoptotic agent in NASH and may be a therapeutic option.

Influence of serum folic acid levels on plasma homocysteine concentrations in patients with rheumatoid arthritis

The purpose of this study was to investigate whether negative effects of methotrexate (mtx) on blood homocysteine (hmc) levels can be prevented with the replacement of folic acid. 42 female patients with rheumatoid arthritis (RA) were studied. Patients were separated into two groups according to their treatment status with mtx (group I: 27 patients taking mtx and folic acid; group II: 15 patients not using mtx). The level of hmc was found to be 6.3+/-2.4 micromol/l in group I and 7.87+/-3.2 micromol/l in group II (p>0.05). Folic acid levels of group I and II were found to be 21.3+/-15.9 ng/ml and 8.41+/-2.86 ng/ml respectively (p<0.001). There was a statistically-significant correlation between age and hmc levels (r=0.386, p=0.012). Negative statistically-significant correlations were observed between folic acid and hmc levels. The effects of mtx on hmc can be prevented with the replacement of folic acid.

White Blood Cell Count and C-reactive Protein Predict Short-term Prognosis in Acute Myocardial Infarction

An elevated white blood cell (WBC) count and C-reactive protein (CRP) concentration are associated with acute myocardial infarction (AMI) and long-term mortality in patients with coronary artery disease. Their relationship with short-term prognosis following AMI is less clear, however. We investigated the relationship between WBC count and CRP concentration, obtained at the time of admission, and the development of subsequent ischaemic coronary events (SICE) within 30 days of AMI in 177 patients. After adjustment for confounding factors, CRP concentration was found to be a strong independent predictor for SICE within 30 days in patients with AMI. WBC count was not found to be an independent predictor, but there was a strong correlation between high WBC counts and the onset of SICE within 30 days in patients with AMI. We conclude that CRP concentration and WBC count could be used to predict the short-term prognosis of patients with AMI.