Vitamin D, PTH, and the Metabolic Syndrome in Severely Obese Subjects

Prevalence of metabolic syndrome with different serum vitamin D levels in middle-aged and older adults

BACKGROUND

The relationship between serum vitamin D levels and metabolic syndrome (MetS) has been controversial. This study focused on the relationship between the prevalence of MetS and serum vitamin D levels in middle-aged and elderly people.

METHODS

This study included middle-aged and older adults who participated in the 2023 Zhejiang Provincial Nutrition and Health Survey, which was conducted in 90 districts and counties in Zhejiang Province, China.

RESULTS

A total of 11,305 participants were included in this study. MetS was prevalent in 31.7% of participants. Vitamin D and vitamin D3 concentrations were inversely associated with MetS prevalence (Ptrend<0.05), but not with vitamin D2, regardless of whether logistic regression models were adjusted for confounding factors. After adjusting for age, sex, physical activity level, smoking status, education level, annual per capita household income, and body mass index residuals, the highest tertile (Q3) of vitamin D (odds ratio [OR], 0.779; 95% confidence interval [CI], 0.702-0.865) and vitamin D3 (OR, 0.787; 95% CI, 0.709-0.875) concentrations had a lower risk of MetS than the lowest tertile (Q1). We found that vitamin D and D3 levels were correlated with age (Pinteraction<0.05). When age-stratified analyses were performed, vitamin D and vitamin D3 levels were significantly negatively associated with MetS in older adults but not in middle-aged adults.

CONCLUSIONS

Low total serum vitamin D and vitamin D3 levels were associated with a higher risk of MetS in adults aged 60 years and older.

Associations between Aging and Vitamin D Status with Whole-Body Nitric Oxide Production and Markers of Endothelial Function

BACKGROUND

Aging and vitamin D deficiency have been associated with reduced nitric oxide (NO) synthesis and impaired endothelial function (EF) but the evidence in humans remains weak.

OBJECTIVES

Two independent cross-sectional studies were designed to evaluate the association between age, sex, and plasma vitamin D concentrations with physiological and biochemical biomarkers of NO synthesis and EF in young and older healthy participants (Study 1) and in overweight and obese postmenopausal females (Study 2).

METHODS

In Study 1, 40 young (20-49 y) and older (50-75 y) males and females (10 participants per age and sex group) were included. Resting blood pressure and ear-to-finger peripheral pulse wave velocity (PWV) were measured. A stable-isotopic method was used to determine whole-body NO production. Plasma 25-hydroxyvitamin D (25(OH)D), nitrate, nitrite, and asymmetric dimethylarginine (ADMA) concentrations were determined. In Study 2, 80 older overweight and obese females (age 61.2 ± 6.2 y, body mass index 29.5 ± 4.4 kg/m2) were recruited. Postocclusion reactive hyperemia (PORH) and peripheral PWV were measured. Plasma concentrations of 25(OH)D, nitrate, cyclic guanosine monophosphate, 3-nitrotyrosine (3-NT), endothelin-1, vascular endothelial growth factor, and ADMA were determined.

RESULTS

In Study 1, whole-body NO production was significantly greater in young compared with older participants (0.61 ± 0.30 μmol·h-1·kg-1 compared with 0.39 ± 0.10 μmol·h-1·kg-1, P = 0.01) but there was no evidence of a sex difference (P = 0.81). Plasma 25(OH)D concentration was not associated with PWV (r = 0.18, P = 0.28) or whole-body NO production (r = -0.20, P = 0.22). Plasma ADMA concentration was associated positively with age (r = 0.35, P = 0.03) and negatively with whole-body NO production (r = -0.33, P = 0.04). In Study 2, age was associated with lower PORH (r = -0.28, P = 0.02) and greater ADMA concentrations (r = 0.22, P = 0.04). Plasma 25(OH)D concentration was inversely associated with 3-NT concentrations (r = -0.31, P = 0.004).

CONCLUSIONS

Older age was associated with lower whole-body NO production. Plasma vitamin D concentrations were not associated with NO production or markers of EF but showed a weak, significant correlation with oxidative stress in postmenopausal overweight females.

Association between Serum Vitamin D and Metabolic Syndrome in a Sample of Adults in Lebanon

The evidence on the association between vitamin D and metabolic syndrome (MetS) is inconclusive. This was a cross-sectional study to explore the relationship between vitamin D serum levels and MetS in a sample of Lebanese adults (n = 230), free of diseases that affect vitamin D metabolism, recruited from an urban large university and neighboring community. MetS was diagnosed according to the International Diabetes Federation criteria. A logistic regression analysis was performed taking MetS as the dependent variable, and vitamin D was forced into the model as an independent variable. The covariates included sociodemographic, dietary, and lifestyle variables. The mean (SD) serum vitamin D was 17.53 (12.40) ng/mL, and the prevalence of MetS was 44.3%. Serum vitamin D was not associated with MetS (OR = 0.99 (95% CI: 0.96, 1.02), p < 0.757), whereas the male sex, compared with the female sex and older age, was associated with higher odds of having MetS (OR = 5.92 (95% CI: 2.44, 14.33), p < 0.001 and OR = 1.08 (95% CI: 1.04, 1.11), p < 0.001, respectively). This result adds to the controversy in this field. Future interventional studies are warranted to better understand the relationship between vitamin D and MetS and metabolic abnormalities.

Serum 25-hydroxyvitamin D levels and dyslipidemia: a systematic review and dose-response meta-analysis of epidemiologic studies

CONTEXT

Findings of previous observational studies that examined the association between circulating vitamin D levels and lipid profiles have been inconsistent.

OBJECTIVE

A dose-response meta-analysis of epidemiologic studies was conducted to investigate the relationship between serum 25-hydroxyvitamin D levels and dyslipidemia in adults.

DATA SOURCES

Electronic databases were searched systematically for articles published up to June 2021.

DATA EXTRACTION

Fifty-seven observational studies and 2 cohort studies that reported odds ratios (ORs) or relative risks (RRs) with 95%CIs for dyslipidemia in relation to serum 25-hydroxyvitamin D levels in adults were included.

DATA ANALYSIS

A high level, vs a low level, of serum 25-hydroxyvitamin D was related to a significant 19% decrease in the odds of hypertriglyceridemia (OR 0.81; 95%CI, 0.74-0.89), an 18% reduction in low high-density lipoprotein cholesterol (HDL-C) (OR 0.82; 95%CI, 0.76-0.89), and an 18% reduction in dyslipidemia (OR 0.82; 95%CI, 0.75-0.91). No significant association was found between a high vs a low level of serum 25-hydroxyvitamin D and risk of high low-density lipoprotein cholesterol (LDL-C) levels (OR 0.86; 95%CI, 0.62-1.19) or hypercholesterolemia (OR 1.03; 95%CI, 0.93-1.15). Dose-response analyses demonstrated that each 10 ng/mL increase in the serum 25-hydroxyvitamin D level was linked, respectively, to a 7% (OR 0.93;95%CI, 0.85-1.02), a 3% (OR 0.97; 95%CI, 0.90-1.05), and a 4% (OR 0.96; 95%CI, 0.92-1.00) marginally significant decrease in the odds of hypertriglyceridemia, low HDL-C, and dyslipidemia.

CONCLUSION

Higher serum 25-hydroxyvitamin D levels are associated with significant reductions in the odds of hypertriglyceridemia, low HDL-C, and dyslipidemia in a dose-response trend.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021219484.

Serum vitamin D and cardiometabolic risk factors in the UK population

Low serum 25-hydroxyvitamin D (25(OH)D) concentrations have been associated with greater adiposity and an adverse cardiometabolic risk profile, yet findings are inconsistent and the role of vitamin D status in cardiovascular disease (CVD) remains uncertain. We aimed to examine the associations between serum 25(OH)D and CVD risk factors in the British population. We analysed data on 2842 subjects aged ≥40 years enrolled in the National Diet and Nutrition Survey (NDNS 2008-2018). Based on serum 25(OH)D concentrations, study subjects were grouped in three categories: vitamin D deficiency (<25 nmol/L), vitamin D insufficiency (25-49 nmol/L) and vitamin D sufficiency status (≥50 nmol/mL). Differences in CVD risk factors between vitamin D deficiency or insufficiency and vitamin D sufficiency status were expressed in standard deviation scores (SDSs) and estimated through weighted multiple linear regression models. We found that vitamin D deficiency was directly associated with BMI, waist circumference, triglycerides and inversely associated with high-density lipoprotein cholesterol (HDL) values. The strongest associations were found between vitamin D deficiency and triglycerides (0.50 SDS, 95% CI: 0.24, 0.77) among men, and vitamin D deficiency and waist circumference (0.70 SDS, 95% CI: 0.56, 0.94), BMI (0.63 SDS, 95% CI: 0.39, 0.88) and triglycerides (0.54 SDS, 95% CI: 0.30, 0.77) among women. When adjusting for BMI the association with triglyceride attenuated (from 0.50 SDS to 0.39 SDS among men and from 0.54 SDS to 0.30 SDS among women). Our data indicates a relationship between inadequate vitamin D status and an adverse CVD risk profile. However, interventional studies are needed to establish possible benefits of vitamin D supplementation on cardiovascular risk. This article is protected by copyright. All rights reserved.

Serum and Dietary Vitamin D in Individuals with Class II and III Obesity: Prevalence and Association with Metabolic Syndrome

The association between vitamin D deficiency and metabolic syndrome (MS) in severe obesity is unclear and controversial. We analyzed serum and dietary vitamin D and their association with MS in 150 adults with class II and III obesity (BMI ≥ 35 kg/m2) from the DieTBra Trial (NCT02463435). MS parameters were high fasting blood glucose, low HDL cholesterol, high triglycerides, elevated waist circumference, and hypertension. Vitamin D deficiency was considered as a level < 20 ng/mL. We performed multivariate Poisson regression adjusted for sociodemographic and lifestyle variables. The prevalence of serum vitamin D deficiency was 13.3% (mean 29.9 ± 9.4 ng/mL) and dietary vitamin D median was 51.3 IU/day. There were no significant associations between vitamin D, serum, and diet and sociodemographic variables, lifestyle, and class of obesity. Serum vitamin D deficiency was associated with age ≥ 50 years (p = 0.034). After a fully adjusted multivariate Poisson regression, MS and its parameters were not associated with serum or dietary vitamin D, except for lower HDL, which was associated with serum vitamin D deficiency (PR = 0.71, 95% CI 0.52-0.97; p = 0.029). Severe obese individuals had a low prevalence of vitamin D deficiency, which was not associated with MS.

Vitamin A and D Absorption in Adults with Metabolic Syndrome versus Healthy Controls: A Pilot Study Utilizing Targeted and Untargeted LC-MS Lipidomics

SCOPE

Persons with metabolic syndrome (MetS) absorb less vitamin E than healthy controls. It is hypothesized that absorption of fat-soluble vitamins (FSV) A and D2 would also decrease with MetS status and that trends would be reflected in lipidomic responses between groups.

METHODS AND RESULTS

Following soymilk consumption (501 IU vitamin A, 119 IU vitamin D2 ), the triglyceride-rich lipoprotein fractions (TRL) from MetS and healthy subjects (n = 10 age- and gender-matched subjects/group) are assessed using LC-MS/MS. Absorption is calculated using area under the time-concentration curves (AUC) from samples collected at 0, 3, and 6 h post-ingestion. MetS subjects have ≈6.4-fold higher median vitamin A AUC (retinyl palmitate) versus healthy controls (P = 0.07). Vitamin D2 AUC is unaffected by MetS status (P = 0.48). Untargeted LC-MS lipidomics reveals six phospholipids and one cholesterol ester with concentrations correlating (r = 0.53-0.68; P < 0.001) with vitamin A concentration.

CONCLUSIONS

The vitamin A-phospholipid association suggests increased hydrolysis by PLB, PLRP2, and/or PLA2 IB may be involved in the trend in higher vitamin A bioavailability in MetS subjects. Previously observed differences in circulating levels of these vitamins are likely not due to absorption. Alternate strategies should be investigated to improve FSV status in MetS.

Analysis of angiographic characteristics and intervention of vitamin D in type 2 diabetes mellitus complicated with lower extremity arterial disease

AIMS

Previous studies have suggested that type 2 diabetes mellitus with lower extremity arterial disease is related to 25-hydroxyvitamin D deficiency. The purpose of this study is to explore the relation between vitamin D supplementation and the characteristics of type 2 diabetes mellitus complicated with lower extremity arterial disease.

METHODS

The clinical data of 514 patients and 148 healthy subjects treated in the First Hospital of Lanzhou University from January 2012 to June 2019 were collected, including the clinical data, ankle-brachial index, and medical records of lower limb artery angiography. We divided the patients into control group (NC group), type 2 diabetes mellitus group (DM group), lower extremity artery disease in type 2 diabetes mellitus without vitamin D supplement group (DM1 group) and lower extremity artery disease in type 2 diabetes mellitus with vitamin D supplement group (DM2 group). The level of serum 25(OH)D was analyzed and the characteristics of arterial lesions of lower extremities were compared by DSA arteriography in DM1 and DM2 group, respectively.

RESULTS

Compared with the NC group, serum 25(OH)D level decreased in DM group (25.39 ± 4.94 ng/mL vs 19.43 ± 5.98 ng/mL) and significantly decreased in DM1 and DM2 group (14.22 ± 5.64 ng/mL vs 17.36 ± 6.25 ng/mL). However, the level of serum 25(OH)D in the DM2 group was higher than that in the DM1 group. Compared with the DM1 group, the disease rate of the inferior knee artery (65% vs 39.3%) and occlusion rate (11.5% vs 3.7%)were decreased in the DM2 group (P < 0.05). Logistic stepwise regression analysis showed that serum 25(OH)D level was a risk factor for lower extremity arterial disease in patients with type 2 diabetes mellitus (OR = 0.898,95%CI = 0.856-0.942).

CONCLUSIONS

The serum level of 25(OH)D in patients with type 2 diabetes mellitus complicated with lower extremity arterial disease is decreased, and level of 25 (OH) D is related to stenosis and occlusion rate, especially in inferior genicular artery in T2DM complicated with LEAD. A high level of 25(OH)D may be a protective factor in type 2 diabetes with lower extremity arterial disease.

Association Between Visceral Adipose Tissue and Estradiol with Bone Health among Obese Women with Metabolic Syndrome

BACKGROUND AND OBJECTIVE

Visceral Adipose Tissue (VAT) which is associated with a higher risk of Metabolic Syndrome (MS) shows adverse effects on bone health. Moreover, MS is associated with high concentrations of serum estradiol (E2), which is essential for bone, as it inhibits bone resorption. This study aimed to investigate the impact of visceral fat and serum E2 levels on bone health markers (vitamin D, C-terminal peptide, Ca and BMD) in obese women with and without MS.

MATERIALS AND METHODS

This cross-sectional study was conducted on 64 obese women, with and without MS. Waist Circumference (WC) was measured in cm. Bone Mineral Density (BMD) was assessed by energy X-ray absorptiometry (DEXA), VAT was evaluated using Body Composition Analyzer "Tanita". Serum E2, C-terminal peptide and vitamin D (Vit. D) were assessed using ELISA technique. Serum calcium (Ca), triglyceride (TG), total cholesterol (Tchol), High Density Lipoproteins (HDL), Low Density Lipoproteins (LDL) and Fasting Blood Sugar (FBS) were also assessed.

RESULTS

In women with MS, VAT showed significant positive correlations with Body Mass Index (BMI), WC and FBS. Whereas, in women without MS, VAT showed significant positive correlations with BMI, TG, age and significant negative correlation with E2. On the other hand, in women with MS, estradiol (E2) had significant negative correlation with age and significant positive correlations with BMD, BMI, FBS and body weight. While, in obese women without MS, it had significant negative correlations with Ca, VAT, age and systolic blood pressure.

CONCLUSION

In obese women with MS, increased VAT, higher BMI, older age and low E2 levels have clinical significance and hence, they should be considered when predicting bone health risk.

Vitamin D deficiency is associated with dyslipidemia: a cross-sectional study in 3788 subjects

BACKGROUND

Previously we reported on severe vitamin D deficiency in a large-scale cohort in the Tangshan area in northern China. However, whether vitamin D deficiency is associated with cardiovascular risk factors has not been systematically examined in the cohort.

OBJECTIVE

We aimed to determine the correlation between serum vitamin D status and lipid levels in circulation via an observational study.

METHODS

Serum 25-hydroxyvitamin D (25[OH]D) was measured. Based on the measurement subjects were classified into quintiles. Dyslipidemia was defined as having one of the following: elevated serum total cholesterol, LDL cholesterol, triglycerides or decreased HDL cholesterol, under lipid-control treatment.

RESULTS

The study was conducted in a total of 3788 adults in northern China during their routine health examinations. When the highest quintile of the 25(OH)D level was set as reference, the risk of having dyslipidemia increased progressively across the highest to the lowest 25(OH)D with ORs of 1 (reference), 1.232 (95% CI, 1.005-1.509), 1.235 (95% CI, 1.007-1.513), 1.403 (95% CI, 1.143-1.735) and 1.494 (95% CI, 1.217-1.833), respectively (P_trend < .0001) after adjustment for age. This trend was unchanged after further adjustment for several potential confounders. In linear regression analysis, we found an inverse significant correlation between 25(OH)D and triglycerides (β coefficient = -0.077, p < .05) and LDL cholesterol (β coefficient = -0.245, p < .05), and positive correlation with HDL cholesterol (β coefficient = 0.038, p = .018).

CONCLUSION

Vitamin D deficiency is found to be associated with dyslipidemia in a cohort of 3788 subjects. Specifically, serum 25(OH)D is inversely correlated with LDL cholesterol and triglycerides levels, and positively correlated with HDL cholesterol level.

Vitamin D level in non-diabetic adult people with metabolic syndrome

AIMS

The aim of this study is comparison the level of Vitamin D deficiency in non-diabetic adult people with metabolic syndrome in Ahvaz.

MATERIAL & METHODS

This descriptive study investigation carried out on a population of individuals with metabolic syndrome. ATPIII criteria were used for metabolic syndrome. Serum concentration of 25 (OH Vit D) of below 5 ng/ml was considered as severe deficiency, 5-10 ng/ml as average deficiency, 10-20 ng/ml as slight deficiency, and above 20 ng/ml as normal.

RESULTS

The results showed mean level of vitamin D was not significant in individuals with and without HTN and in different genders (P > 0.5). No significant difference was found between case and control groups in terms of the distribution level of vitamin D (P > 0.5). In both groups, the difference between blood pressure (systole and diastole) was not significant in cases of severe and average deficiencies. But it was significant different in the group with slight deficiency (P = 0.03). In the case group, 58% of the participants had FBS>100.

CONCLUSION

The group with metabolic syndrome had a higher intensity of vitamin D deficiency compared to the control group.

The relationship between hypovitaminosis D and metabolic syndrome: a cross sectional study among employees of a private university in Lebanon

BACKGROUND

The prevalence of low vitamin D status and metabolic syndrome is increasing globally and in Lebanon. The objectives of this study are to assess the prevalence of metabolic syndrome (MetS) and its components (elevated triglycerides, low HDL, abdominal obesity defined by high waist circumference, hypertension, impaired fasting blood glucose) and investigate the association between serum 25-hydroxyvitamin D (25(OH)D) concentrations and MetS and its components among a sample of Lebanese adults.

METHODS

A cross-sectional study was carried out on Notre Dame University employees. A background questionnaire, a short-form of the International Physical Activity Questionnaire and a food frequency questionnaire were administered. Participants were invited to the nutrition laboratory to gather data on anthropometric (height, waist circumference, weight, body composition and body mass index) and biochemical measurements (serum vitamin D, triglycerides, HDL and fasting blood glucose). Vitamin D status was assessed according to the Institute of Medicine cut-offs (inadequate or adequate: 25(OH)D < or ≥ 50 nmol/L).The definition of the Third Report of the National Cholesterol Education Program was used to identify individuals who had MetS. The data were analyzed using the SPSS version 22. P < 0.05 was considered statistically significant.

RESULTS

A total of 344 participants (age range of 20 to 74 years) were included in the study. The prevalence of MetS was 23.5%. Among MetS components, central obesity was the most prevalent condition (50.6%), while the least prevalent was impaired fasting blood glucose (20.3%). The odds of having MetS were found to be 2.5 (95% CI 1.3-4.7) higher among those with inadequate vitamin D status, than among those with adequate vitamin D status while controlling for important confounders (age, marital status, education level, income, medical morbidity, smoking and percent body fat and gender). Among the components of MetS, only hypertriglyceridemia (OR: 2.4, 95%CI: 1.3-4.2) and low HDL (OR: 1.8, 95% CI: 1.0-3.0) were associated with inadequate vitamin D status while controlling for important confounders.

CONCLUSIONS

Early identification and control of risk factors for cardiovascular diseases in the primary care level is needed, particularly among adults who have low vitamin D status, are obese, and have low income level.

Relationship Between Vitamin D Status and Vitamin D Receptor Gene Polymorphisms With Markers of Metabolic Syndrome Among Adults

Introduction: Recent studies have demonstrated that vitamin D deficiency contributes to the development of metabolic disorders, including obesity and type 2 diabetes mellitus (T2DM). Several vitamin D receptor (VDR) gene polymorphisms had been described to play a role in these conditions since vitamin D receptors were found in many tissues. The aim of this study was to assess the relationship between vitamin D status and VDR gene polymorphisms with metabolic syndrome (MS) parameters in Russian middle-aged women. Materials and Methods: A total of 697 women aged between 30 to 55 years were included in this cross-sectional study. Serum 25-hydroxyvitamin D (25(OH)D) level and four VDR gene polymorphisms rs1544410 (BsmI), rs7975232 (ApaI), rs731236 (TaqI), and rs2228570 (FokI) were measured. We applied the International Diabetes Federation (IDF) criteria to identify subjects with MS. Results: 9.3% of subjects had normal vitamin D level, while 90.7% were insufficient or deficient. Abdominal obesity (AO) was seen in 75.5%, impaired glucose tolerance (IGT) or T2DM was observed in 33.3%, reduced high-density lipoprotein cholesterol (HDL-C) level in 32.2% and hypertriglyceridemia in 23.4%. Serum 25(OH)D level in women with or without MS did not differ (48.6 ± 1.8 and 51.1 ± 1.5 nmol/l, p > 0.05). Subjects with vitamin D deficiency showed an increased risk of AO [CI 95% 2.23; 1.15-4.30] and low HDL-C [CI95% 2.60; 1.04-6.49] compared to subjects with normal 25(OH)D level. IGT and T2DM risk was increased only when 25(OH)D concentration was less than 39.0 nmol/l [CI 95% 7.17; 2.99-17.7], but risk of MS did not differ in normal vitamin D status subjects and insufficient/deficient ones (p > 0.05). T allele carriers (A) of rs7975232 had higher total cholesterol and low-density lipoprotein cholesterol levels compared with the GG (aa) genotypes. Similarly, GG (BB) genotype carriers of rs1544410 had higher triglyceride levels than subjects with A (b) allele carriers. However VDR gene polymorphisms did not seem to be associated with an increased risk of MS. Conclusions: Vitamin D deficiency, rs7975232, and rs1544410 VDR gene variants are associated with MS parameters in Russian middle-aged women.

Bone Health following Bariatric Surgery: Implications for Management Strategies to Attenuate Bone Loss

Bariatric surgery (BS) is an effective treatment for morbid obesity and its associated comorbidities. Following such a procedure, however, patients are at risk of developing metabolic bone disease owing to the combination of rapid weight loss, severely restricted dietary intake, and reduced intestinal nutrient absorption. Patients undergoing malabsorptive procedures are at a higher risk of postoperative bone health deterioration than those undergoing restrictive procedures; however, studies have demonstrated negative skeletal consequences of restrictive procedures as well. The clinical practice guidelines of some international associations have previously addressed preoperative evaluation and postoperative clinical care in order to maintain bone health in BS patients. Nevertheless, some issues regarding bone health in BS patients remain unclear owing to the lack of relevant randomized clinical trials, including doses of nutritional supplements pre- and post-BS. This review summarizes the current data regarding the skeletal consequences of BS and its mechanisms, with an emphasis on the preventive strategies and nutritional care that may be warranted in order to attenuate bone deterioration following BS.

No effect of vitamin D supplementation on cardiovascular risk factors in subjects with metabolic syndrome: a pilot randomised study

Introduction

Patients with metabolic syndrome (MetS) may have lower 25-hydroxyvitamin D (25(OH)VitD) serum levels compared with non-MetS individuals. Vitamin D (VitD) deficiency is associated with various cardiovascular disease (CVD) risk factors. Yet, the effect of VitD supplementation on MetS remains uncertain. Our aim was to examine the effect of VitD supplementation on CVD risk factors in MetS subjects.

Material and methods

This pilot study had a PROBE (prospective, randomised, open-label, blinded end-point) design. Fifty patients with MetS were included and randomised either to dietary instructions (n = 25) (control group) or dietary instructions plus VitD 2000 IU/day (n = 25) (VitD group) for 3 months. This study is registered in ClinicalTrials.gov (NCT01237769).

Results

In both groups a similar small weight reduction was achieved. In the VitD group serum 25(OH)VitD levels significantly increased by 91% (from 16.0 (3.0–35.0) to 30.6 (8.4–67.0) ng/ml, p < 0.001), while in the control group no significant change was observed (from 10.0 (4.0–39.6) to 13.0 (3.5–37.0) ng/ml). In both groups triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting glucose, haemoglobin A_1c, homeostasis model assessment index and diastolic blood pressure did not significantly change. Systolic blood pressure decreased by 3.7% (from 134 ±14 to 129 ±13 mm Hg, p = 0.05) in the VitD group, while it decreased by 1.5% (from 132 ±13 to 130 ±16 mm Hg, p = NS) in the control group (p = NS between groups). In the VitD group serum 25(OH)VitD increase was negatively correlated with SBP decrease (r = –0.398, p = 0.049).

Conclusions

VitD supplementation (2000 IU/day) did not affect various CVD risk factors in patients with MetS.

Extraskeletal actions of vitamin D

The vitamin D receptor (VDR) is found in nearly all, if not all, cells in the body. The enzyme that produces the active metabolite of vitamin D and ligand for VDR, namely CYP27B1, likewise is widely expressed in many cells of the body. These observations indicate that the role of vitamin D is not limited to regulation of bone and mineral homeostasis, as important as that is. Rather, the study of its extraskeletal actions has become the major driving force behind the significant increase in research articles on vitamin D published over the past several decades. A great deal of information has accumulated from cell culture studies, in vivo animal studies, and clinical association studies that confirms that extraskeletal effects of vitamin D are truly widespread and substantial. However, randomized, placebo-controlled clinical trials, when done, have by and large not produced the benefits anticipated by the in vitro cell culture and in vivo animal studies. In this review, I will examine the role of vitamin D signaling in a number of extraskeletal tissues and assess the success of translating these findings into treatments of human diseases affecting those extracellular tissues.

Association of 25-hydroxyvitamin D and parathyroid hormone with the metabolic syndrome in black South African women

The relationship between 25 hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH) and metabolic traits appear to differ among ethnicities and may be influenced by obesity. The aim of the study was to examine the association of serum 25(OH)D or PTH with metabolic syndrome (MetS) while controlling for adiposity in black women. Using a cross-sectional study design, 209 urban black women aged ≥ 43 years from the North West Province, South Africa, were included. Multiple regression models were used to explore the relationship between 25(OH)D or PTH and body composition. To explore the association between 25(OH)D or PTH and MetS, a separate variable was created including at least 3 of the MetS criteria, but excluding elevated waist circumference as a diagnostic criterion in a logistic regression model. The majority of the women (69.9%) were overweight or obese and 65.5% of the women had excessive adiposity using the age-specific cut-off points for body fat percentage. All body composition variables were positively associated with PTH, whereas body mass index and waist circumference, but not body fat percentage, had negative associations with 25(OH)D also after adjusting for confounders. Before and after adjusting for age, body fat, habitual physical activity, tobacco use, season of data collection, and estimated glomerular filtration rate, neither 25(OH)D nor PTH showed significant associations with MetS. Although PTH was positively associated and 25(OH)D was negatively associated with adiposity in black women, there was no association between either 25(OH)D or PTH and MetS in this study population, nor did adiposity influence these relationships.

Standardized serum 25-hydroxyvitamin D concentrations are inversely associated with cardiometabolic disease in U.S. adults: a cross-sectional analysis of NHANES, 2001-2010

BACKGROUND

Previously reported associations between vitamin D status, as measured by serum 25-hydroxyvitamin D [25(OH)D] concentrations, and cardiometabolic risk factors were largely limited by variability in 25(OH)D assay performance. In accordance with the Vitamin D Standardization Program, serum 25(OH)D measurement was recently standardized in the National Health and Nutrition Examination Survey (NHANES) to reduce laboratory and method related differences in serum 25(OH)D results. We evaluated the overall and ethnic-specific associations between the newly standardized serum 25(OH)D concentrations and cardiometabolic risk in U.S. adults.

METHODS

This study examined standardized 25(OH)D data from five cycles of the NHANES (2001-2010). The total sample included 7674 participants (1794 Mexican-Americans, 4289 non-Hispanic whites, and 1591 non-Hispanic blacks) aged ≥ 20 years who were examined in the morning after overnight fasting. Serum 25(OH)D was directly measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 2007-2010, and was predicted from LC-MS/MS equivalents for 2001-2006. Serum 25(OH)D levels were categorized into quartiles (<43.4, 43.4-58.6, 58.7-74.2, ≥74.3 nmol/L). Cardiometabolic risk was defined by the homeostatic model assessment of insulin resistance (HOMA-IR), metabolic syndrome (MetS), and Framingham cardiovascular disease (CVD) risk. Prevalence ratios and 95% confidence intervals were calculated using modified Poisson regression.

RESULTS

After full adjustment for confounders, serum 25(OH)D ≥74.3 nmol/L was associated with lower cardiometabolic risk compared to 25(OH)D <43.4 nmol/L in the overall sample [HOMA-IR: 0.70 (0.59, 0.84); MetS: 0.82 (0.74, 0.91); CVD risk: 0.78 (0.66, 0.91)]. These associations remained significant in Mexican-Americans [HOMA-IR: 0.54 (0.35, 0.82); MetS: 0.73 (0.55, 0.96)], non-Hispanic whites [HOMA-IR: 0.81 (0.68, 0.96); MetS: 0.84 (0.73, 0.95); CVD risk: 0.78 (0.64, 0.93)]; and in non-Hispanic blacks [HOMA-IR: 0.67 (0.45, 0.99); MetS: 0.75 (0.56, 0.97); CVD risk: 0.58 (0.41, 0.81)].

CONCLUSIONS

Low vitamin D status is a significant risk factor for cardiometabolic disease in U.S. adults based on standardized serum 25(OH)D results, irrespective of ethnic background. Future studies using standardized 25(OH)D data are needed to confirm these results, particularly amongst U.S. blacks with 25(OH)D concentrations above 75 nmol/L.

Relationship between the Finnish Diabetes Risk Score (FINDRISC), vitamin D levels, and insulin resistance in obese subjects

AIM

To assess the relationship between 25-hydroxyvitamin D [25(OH)D] blood concentrations in subjects with obesity and type 2 diabetes mellitus (T2D) risk according to the Finnish Diabetes Risk Score (FINDRISC) modified for Latin America (LA-FINDRISC).

METHODS

This study was conducted in Ciudad Bolívar, Venezuela. Eighty two women and 20 men (53 obese and 49 nonobese), with an average age of 42.6±12.30 years were enrolled. Weight, height, body mass index (BMI), waist circumference (WC), fasting glucose, basal insulin, plasma lipids, Homeostasis Model Assessment-Insulin Resistance (HOMA-IR), and 25(OH)D levels were measured. FINDRISC with WC cutoff points modified for Latin America was applied.

RESULTS

No difference in 25(OH)D levels between obese and nonobese subjects was found. When anthropometric, clinical, and biochemical variables according to the 25(OH)D status were compared, the only difference detected was higher LA-FINDRISC in the insufficient/low 25(OH)D group compared to normal 25(OH)D levels group (12.75±6.62; vs 10.15±5.21; p=0.031). LA-FINDRISC was negatively correlated with plasma 25(OH)D levels (r=-0.302; p=0.002) and positively correlated with the HOMA-IR index (r=0.637; p=0.0001).

CONCLUSIONS

The LA-FINDRISC significantly correlated with both 25(OH)D levels and insulin resistance markers in this group of patients.

Vitamin D, parathyroid hormone, and serum lipid profiles in a middle-aged and elderly Chinese population

OBJECTIVES

To explore the associations of serum vitamin D and parathyroid hormone (PTH) levels with serum lipid profiles and the risk of hyperlipidemia in a middle-aged and elderly population.

METHODS

A population-based cross-sectional study was conducted in the spring of 2012 among 1,203 Chinese participants, aged 52 to 101 years. 25-Hydroxyvitamin D [25(OH)D] was measured by chemiluminescence assay. (PTH) levels were measured with an electrochemiluminescence immunoassay (ECLIA) method.

RESULTS

A total of 1,203 participants, including 526 women (43.7%), were evaluated in 2012. The median concentrations of serum 25(OH)D and PTH for the entire group were 17.3 ng/mL and 38.3 pg/mL, respectively. Serum 25(OH)D and PTH levels were not independently associated with serum total cholesterol, triglycerides, low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol levels in a multivariate adjusted linear regression analysis of 1,027 participants not receiving antihyperlipidemic treatment (P>.05). In logistic regression analyses, serum 25(OH)D and PTH levels were not associated with a risk of hyperlipidemia after adjustment for age, sex, heavy drinking, smoking, diabetes, obesity, family history of hyperlipidemia, body mass index (BMI), physical activity, glomerular filtration rate (GFR), fasting glucose, high-sensitivity C-reactive protein (hsCRP), calcium, and hemoglobin.

CONCLUSIONS

Serum 25(OH)D and PTH levels are not independently associated with serum lipid levels or an increased risk of hyperlipidemia in a middle-aged and elderly Chinese population.

Vitamin D level and its association with adiposity among multi-ethnic adults in Kuala Lumpur, Malaysia: a cross sectional study

Background

Vitamin D deficiency is highly prevalent in both temperate as well as tropical countries. Obesity is one of the factors contributing to vitamin D deficiency. As our country has a high prevalence of overweight and obesity, we aimed to study serum 25-hydroxyvitamin D (25(OH)D) level and its association with adiposity using various adiposity indicators; and to study other risk factors that affect serum 25(OH)D level among multi-ethnic adults in Kuala Lumpur, Malaysia.

Methods

This was a cross sectional study conducted with a multistage sampling. All permanent teachers working in government secondary schools in Kuala Lumpur were invited for the study. The data collection included serum 25(OH)D, Parathyroid Hormone (PTH), body fat percentage, waist circumference, body mass index (BMI) and blood pressure. Demographic characteristics, sun avoidance, sun exposure and physical activity were enquired from the participants using a self-administered questionnaire. The data was analyzed using a complex sample analysis.

Results

A total of 858 participants were recruited. Majority of them were Malays, females and had tertiary education. The overall prevalence of vitamin D deficiency (<20 ng/ml) was 67.4 %. Indian participants (80.9 %) had the highest proportion of vitamin D deficiency, followed by Malays (75.6 %), others (44.9 %) and Chinese (25.1 %). There was a significant negative association between serum 25(OH)D level with BMI (β = −0.23) and body fat percentage (β = −0.14). In the multivariate linear regression analysis, Malays, Indians and females (p < 0.001); higher BMI and larger waist circumference (p < 0.05) were significantly associated with lower serum 25(OH)D level. The full model explained 32.8 % of the variation between participants in the serum 25(OH)D level. The two most influential factors affecting serum 25(OH)D level were ethnicity and gender.

Conclusions

The prevalence of vitamin D deficiency among our participants was high. Adiposity was associated with serum 25(OH)D level. Skin pigmentation and gender based behaviours were more dominant in contributing to serum 25(OH)D level. Health education should be targeted in weight management, gender based behaviours on sun exposure, as skin pigmentation is non-modifiable.

Calcium and Vitamin D in Obesity and Related Chronic Disease

There is a pandemic of lifestyle-related diseases. In both developed and lesser developed countries of the world, an inadequacy of calcium intake and low vitamin D status is common. In this chapter, we explore a mechanistic framework that links calcium and vitamin D status to chronic conditions including obesity, systemic inflammation, endothelial dysfunction, dyslipidemia and cardiovascular disease, and type 2 diabetes mellitus. We also update the available clinical evidence, mainly from randomized controlled trials, to provide a synthesis of evidence in favor or against these hypotheses. There is consistent data to support calcium increasing whole body fat oxidation and increasing fecal fat excretion, while there is good cellular evidence for vitamin D reducing inflammation. Clinical trials support a marginal reduction in circulating lipids and some meta-analysis support an increase in insulin sensitivity following vitamin D. However, these mechanistic pathways and intermediate biomarkers of disease do not consistently transcribe into measurable health outcomes. Cementing the benefits of calcium and vitamin D for extraskeletal health needs a reexamination of the target 25(OH)D level to be achieved and the minimum duration of future trials.

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Abnormal calcium, 25(OH)vitamin D, and parathyroid hormone after biliopancreatic diversion; correction through elongation of the common tract and reduction of the gastric pouch

BACKGROUND

Biliopancreatic diversion (BPD) is a surgical technique burdened, in some instances, by clinical evidence of malabsorption and intractable diarrhoea.

OBJECTIVES

To compare calcium metabolism together with weight in patients undergoing BPD versus BPD followed by revisional surgery because of side effects of BPD or ineffectiveness of BPD.

SETTING

University hospital.

METHODS

Twenty-seven patients underwent BPD. After a median period of 48 months, they underwent revisional surgery (elongation of the common limb from 50 to 200 cm and reduction of the gastric pouch from 500 to 40 mL) and were observed for a total period of 120 months; 40 patients only underwent BPD (controls) and were observed for an identical period.

RESULTS

At baseline, 24 patients (8 revisional surgery and 16 controls) had increased parathyroid hormone (PTH) levels, and only 3 patients had normal 25(OH)vitamin D levels; calcium declined, even within normal limits, and PTH increased in the revisional surgery group. After revisional surgery, patients experienced a further decrease of weight, together with a reduction of PTH levels, an increase of 25(OH)vitamin D levels, and an increase of calcium levels. Weight loss was inverserly associated with an increase of 25(OH)vitamin D and directly associated with change of PTH.

CONCLUSION

This study suggests that it is possible to control effects of BPD on calcium metabolism through a revisional procedure leading to lesser malabsorption and to greater restriction of the gastric pouch. It should be considered in the presence of significant side effects due to excessive malabsorption.

Relationship Between Parathormone and Obesity-Linked Disorders

BACKGROUND

In this study, we aimed to investigate whether high parathormone (PTH) levels in obese patients contribute to the metabolic complications of obesity.

METHODS

A total of 400 obese subjects aged 18-65 years were included. Anthropometric bioelectrical bioimpedance measures, blood tests, and 75 gram oral glucose tolerance test results were evaluated.

RESULTS

Of the 400 obese subjects, 335 were female. The mean age was 39 ± 10 years. The median body mass index was 36 (interquartile range 34-41). Subjects were divided into quartiles according to blood PTH levels. Groups included quartile 1 [n = 100, median PTH; 42 (range 36-45)], quartile 2 [n = 100, median PTH; 55 (51-59)], quartile 3 [n = 100, median PTH; 73 (68-78)], and quartile 4 [n = 100, median PTH; 99 (89-125)]. Quartiles were evaluated with a generalized linear model adjusted for age, sex, and season of recruitment. Systolic and diastolic blood pressure, fasting glucose, homeostatic model assessment-estimated insulin resistance, insulin sensitivity index, triglyceride level, and high-density lipoprotein cholesterol (HDL-C) were not different among quartiles. PTH and 25 hydroxyvitamin D (25(OH)D) were not associated with higher odds of prevalent metabolic syndrome in obese subjects (odds ratio, OR, 0.99 [95% confidence interval, CI, 0.981.00], P = 0.38 and 0.99 95% CI 0.96-1.01], P = 0.46, respectively). Decreased 25(OH)D levels were significantly correlated with higher odds of low HDL-C (OR 0.96 [95% CI 0.93-0.99], P = 0.04).

CONCLUSIONS

PTH does not contribute to the occurrence of metabolic components of obesity, but there is a positive correlation between 25(OH)D and HDL-C.

Associations of circulating 25(OH)D with cardiometabolic disorders underlying type 2 diabetes mellitus in an Aboriginal Canadian community

AIMS

To investigate the associations of 25-hydroxyvitamin D (25(OH)D) with insulin resistance (IR), beta-cell function and metabolic syndrome (MetS) in a First Nations population.

METHODS

We conducted a cross-sectional analysis using data from the Sandy Lake Health and Diabetes Project (2003-2005). A total of 390 participants (>12 y) were assessed for 25(OH)D, fasting glucose, insulin, lipids, blood pressure, inflammatory markers, anthropometric and lifestyle variables and a 75-g oral glucose tolerance test was administered. IR was calculated using the Matsuda insulin sensitivity index (ISOGTT) and the computational homeostasis model assessment of IR (HOMA2-IR). Beta-cell function was calculated using the insulinogenic index (IGI) divided by HOMA-IR (IGI/IR) and the insulin secretion sensitivity index-2 (ISSI-2). The 2009 harmonized criteria were used to define MetS.

RESULTS

Higher 25(OH)D was associated with a decreased prevalence of dysglycemia (OR = 0.71 95% CI, 0.51-0.97 per SD increase). In addition, there were significant associations of 25(OH)D with measures of insulin action (ISOGTT; beta=0.31; 95% CI, 0.12, 0.49; HOMA2-IR; beta = -29; 95% CI -0.46, -0.11 and beta-cell function (ISSI-2; beta = 0.15; 95% CI, 0.02, 0.28). The prevalence of MetS was 41%. There was a decreased risk (OR=0.73, 95% CI 0.56, 0.94) of MetS per SD increase in baseline 25(OH)D. Finally, there was a significant positive association of 25(OH)D with adiponectin (beta = 0.16; 95% CI = 0.01, 0.31).

CONCLUSIONS

These results support a potential role for vitamin D metabolism in the natural history of T2DM among Aboriginal Canadians, although carefully designed randomized trials will be required to establish causality.

Lower bone turnover markers in metabolic syndrome and diabetes: the population-based Study of Health in Pomerania

BACKGROUND AND AIMS

Accumulating evidence demonstrates an important interaction between bone and energy metabolism. We aimed to study the associations of three bone turnover markers (BTM: osteocalcin, beta-crosslaps, procollagen type 1 N-terminal propeptide) as well as of 25-hydroxyvitamin D and parathyroid hormone with metabolic syndrome (MetS) or type 2 diabetes mellitus (T2DM) in a large population-based cohort.

METHODS AND RESULTS

This cross-sectional study comprised 2671 adult men and women participating in the first follow-up of the population-based Study of Health in Pomerania (SHIP-1). Multivariable logistic regression analyses were performed to assess sex-specific associations between the BTMs, 25-hydroxyvitamin D or parathyroid hormone and metabolic disease. All models were adjusted for age, body mass index, smoking status, physical activity, estimated glomerular filtration rate and month of blood sampling. The models for women were further adjusted for menopausal status. Higher BTM or 25-hydroxyvitamin D concentrations were associated with significantly lower odds for metabolic disease, while there was no association between parathyroid hormone and MetS or T2DM.

CONCLUSION

Our results contribute to the accumulating evidence of a cross-sectional association between high BTM or 25-hydroxyvitamin D concentrations and a lower prevalence of MetS or T2DM. Further research is necessary to evaluate the mechanisms underlying these results.

Vitamin D status and hypertension: a review

Vitamin D is a steroid prohormone synthesized in the skin following ultraviolet exposure and also achieved through supplemental or dietary intake. While there is strong evidence for its role in maintaining bone and muscle health, there has been recent debate regarding the role of vitamin D deficiency in hypertension based on conflicting epidemiological evidence. Thus, we conducted a scoping systematic literature review and meta-analysis of all observational studies published up to early 2014 in order to map trends in the evidence of this association. Mixed-effect meta-analysis was performed to pool risk estimates from ten prospective studies (n=58,262) (pooled risk for incident hypertension, relative risk [RR] =0.76 (0.63–0.90) for top vs bottom category of 25-hydroxyvitamin D [25OHD]) and from 19 cross-sectional studies (n=90,535) (odds ratio [OR] =0.79 (0.73–0.87)). Findings suggest that the better the assessed quality of the respective study design, the stronger the relationship between higher 25OHD levels and hypertension risk (RR =0.67 (0.51–0.88); OR =0.77 (0.72–0.89)). There was significant heterogeneity among the findings for both prospective and cross-sectional studies, but no evidence of publication bias was shown. There was no increased risk of hypertension when the participants were of older age or when they were vitamin D deficient. Younger females showed strong associations between high 25OHD levels and hypertension risk, especially in prospective studies (RR =0.36 (0.18–0.72); OR =0.62 (0.44–0.87)). Despite the accumulating evidence of a consistent link between vitamin D and blood pressure, these data are observational, so questions still remain in relation to the causality of this relationship. Further studies either combining existing raw data from available cohort studies or conducting further Mendelian analyses are needed to determine whether this represents a causal association. Large randomized controlled trials are also needed to determine whether vitamin supplementation may be beneficial in the prevention or the treatment of hypertension.

Concentrations of the vitamin D metabolite 1,25(OH)2D and odds of metabolic syndrome and its components

AIM

Few epidemiological studies have investigated the association between circulating concentrations of the active vitamin D metabolite 1,25(OH)2D and metabolic syndrome. We sought to determine whether blood levels of 1,25(OH)2D are associated with metabolic syndrome and its individual components, including waist circumference, triglycerides, blood pressure, and glucose, and high-density lipoprotein. We also investigated these associations for the more abundant precursor vitamin D metabolite, 25(OH)D.

METHODS

Participants from two completed clinical trials of colorectal neoplasia with available metabolic syndrome data and blood samples for measurement of 1,25(OH)2D (n=1048) and 25(OH)D (n=2096) were included. Cross-sectional analyses of the association between concentrations of 1,25(OH)2D, 25(OH)D, metabolic syndrome, and its components were conducted.

RESULTS

A statistically significant inverse association was observed for circulating concentrations of 1,25(OH)2D and metabolic syndrome, with adjusted ORs (95% CIs) of 0.73 (0.52-1.04) and 0.52 (0.36-0.75) for the second and third tertiles of 1,25(OH)2D, respectively (p-trend <0.001). Significant inverse relationships were also observed between 1,25(OH)2D and high triglycerides (p-trend <0.001), and low high-density lipoprotein (p-trend <0.001). For 25(OH)D concentrations, significant inverse associations were found for metabolic syndrome (p-trend <0.01), high waist circumference (p-trend <0.04) and triglyceride levels (p-trend <0.01). Participants with 25(OH)D ≥30 ng/ml and in the highest tertile of 1,25(OH)2D demonstrated significantly lower odds of metabolic syndrome, with an OR (95% CI) of 0.38 (0.19-0.75) compared to those in the lowest category for both metabolites.

CONCLUSION

These results provide new evidence that the relatively rarely-studied active hormonal form of vitamin D, 1,25(OH)2D, is associated with metabolic syndrome and its components, and confirm prior findings for 25(OH)D. The finding that 1,25(OH)2D is related to high-density lipoprotein, while 25(OH)D is not, suggests that there may be an independent mechanism of action for 1,25(OH)2D in relation to metabolic dysregulation.

Relationship between serum 25-hydroxyvitamin D and lower extremity arterial disease in type 2 diabetes mellitus patients and the analysis of the intervention of vitamin D

The aim of this study was to explore the relationship between serum 25-hydroxyvitamin D [25(OH)D] concentrations and lower extremity arterial disease (LEAD) in type 2 diabetes mellitus (T2DM) patients and to investigate the intervention effect of vitamin D. 145 subjects were assigned to a control group (Group NC), T2DM group (Group DM1), and T2DM complicated with LEAD group (Group DM2); then Group DM2 were randomly divided into Group DM3 who received oral hypoglycemic agents and Group DM4 who received oral hypoglycemic drugs and vitamin D3 therapy. Compared to Group NC, 25(OH)D was significantly lower in Group DM2 and marginally lower in Group DM1. In contrast to baseline and Group DM3, 25(OH)D rose while low density lipoprotein (LDL), retinol binding protein 4 (RBP4), and HbA1c significantly lowered in Group DM4. Statistical analysis revealed that 25(OH)D had a negative correlation with RBP4, duration, HbA1c, homeostasis model assessment for insulin resistance (HOMA-IR), and fasting plasma glucose (FPG). LDL, systolic blood pressure (SBP), FPG, and smoking were risk factors of LEAD while high density lipoprotein (HDL) and 25(OH)D were protective ones. Therefore, we deduced that low level of 25(OH)D is significantly associated with the occurrence of T2DM complicated with LEAD.

Serum 25-hydroxyvitamin D levels and metabolic health status in extremely obese individuals

OBJECTIVE

Vitamin D deficiency is prevalent in obese individuals. 25-hydroxyvitamin D [25(OH)D] levels in metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO) adult individuals were examined and the relationship between 25(OH)D levels and other clinical parameters was evaluated.

METHODS

This is a retrospective chart review of outpatient medical records from the Nutrition and Weight Management Center at Boston Medical Center. Subjects were divided into two groups, MHO and MUO, using the homeostasis model assessment of insulin resistance criteria.

RESULTS

A total of 191 obese subjects were included in this analysis. The average body mass index (BMI) was 43.0 ± 9.2 kg/m(2) . Sixty-three subjects (33%) met criteria for MHO. MHO subjects had lower BMI and waist circumferences compared to MUO subjects. 25(OH)D levels were not significantly different between the two groups (P = 0.242). Overall, there were high prevalences of vitamin D deficiency (48.7%) and vitamin D insufficiency (33.0%). 25(OH)D levels were inversely correlated with BMI, body weight, waist circumferences, and HbA1c levels but not with blood pressure, total cholesterol, HDL, triglycerides, or LDL.

CONCLUSIONS

In extremely obese individuals, 25(OH)D levels were not related to metabolic health status or insulin resistance but correlated with the degree of adiposity.

Obesity with and without metabolic syndrome: do vitamin D and thyroid autoimmunity have a role?

AIMS

To investigate serum levels of thyroid stimulating hormone (TSH), anti-thyroid peroxidase antibody (TPO), and 25(OH)D in the presence or absence of metabolic syndrome in an obese population.

METHODS

Data from a prospectively generated "Obesity Polyclinic" database that includes socio-demographic characteristics, anthropometric, and laboratory measurements of obese subjects were retrospectively analyzed. Subjects with body-mass index (BMI) ≥30kg/m(2) were eligible. After detailed analysis and exclusion of unavailable cases, subjects diagnosed with and without metabolic syndrome were compared for TSH, anti-TPO, and 25(OH)D.

RESULTS

Of the study participants (n=548; men/women, 64/484), 277 were diagnosed with metabolic syndrome [Met-S (+)]. Met-S (+) patients had a higher mean BMI (36.4 vs. 32.3kg/m(2), p<.001) and percentage body fat (PBF) (39.2 vs. 35.3%, p<.001), but similar TSH (2.1 vs. 2.2mIU/mL, p=.759), anti-TPO (12 vs. 13IU/mL, p=.483), 25(OH)D (13.2 vs. 12.6ng/mL, p=.409), and calcium-phosphorus product (28.7 vs. 29.5mg/dL, p=0.275), compared to Met-S (-) subjects. When serum TSH, anti-TPO, and 25(OH)D levels were analyzed according to tertiles for comparisons of fasting plasma glucose, triglycerides, high-density lipoprotein cholesterol, BMI, and PBF, only 25(OH)D levels were negatively correlated with BMI and PBF.

CONCLUSIONS

Although decreased 25(OH)D levels were related to the degree of obesity in obese subjects, serum 25(OH)D levels per se did not seem to be associated with metabolic syndrome. The prevalence of thyroid autoimmunity and hypothyroidism were high in this obese sample; however, neither serum TSH nor anti-TPO levels correlated with metabolic syndrome. Our findings did not support the hypothesis that thyroid autoimmunity and/or vitamin D status have a role in the development of metabolic disturbances in the obese population.

Prospective association of 25(OH)D with metabolic syndrome

CONTEXT

Vitamin D may play a role in the aetiology of the metabolic syndrome (MetS), yet the majority of previous studies have been cross-sectional, and the limited number of prospective studies has yielded inconsistent results.

OBJECTIVE

To examine the prospective association of vitamin D [25-hydroxyvitamin D, 25(OH)D] with MetS in a multi-ethnic cohort of adults in Ontario, Canada.

DESIGN

Nondiabetic individuals with pre-existing MetS risk factors were recruited for participation in the PROspective Metabolism and ISlet cell Evaluation (PROMISE) cohort study, a longitudinal study of the determinants of insulin resistance and MetS.

METHODS

Of the 654 participants enrolled at baseline, 489 attended a 3-year follow-up visit. There were 301 participants eligible for the analysis of 25(OH)D with incident MetS (age 49·2 ± 9·3 years old, 75·4% female), after excluding 188 (38·5%) prevalent MetS cases at baseline. Longitudinal change in MetS components was assessed in the entire follow-up cohort.

RESULTS

There were 76 (15·5%) participants who developed MetS over the 3-years of follow-up. Multivariate logistic regression analyses indicated a decreased risk of MetS at follow-up per standard deviation increase in baseline 25(OH)D after adjustment for sociodemographics, season, baseline and change in supplement use and physical activity and insulin resistance (OR = 0·63, 95% CI 0·44-0·90). Multivariate linear regression analyses revealed a significant inverse association of baseline 25(OH)D with fasting glucose at follow-up (β = -0·0005, P = 0·025).

CONCLUSIONS

There was a significant inverse association of baseline 25(OH)D with incident MetS, which may be partly driven by its association with glucose homoeostasis.

Plasma 25-hydroxyvitamin D and risk of metabolic syndrome: an ancillary analysis in the Diabetes Prevention Program

BACKGROUND/OBJECTIVES

Low blood levels of 25-hydroxyvitamin D (25OHD) have been associated with cardiometabolic disease but results are inconsistent. The objective of the study was to investigate the association of 25OHD with metabolic syndrome in a population at increased risk for diabetes.

SUBJECTS/METHODS

Using baseline data from the placebo and lifestyle intervention arms of the Diabetes Prevention Program (N=2000), multivariable logistic regression models were used to estimate the odds of prevalent metabolic syndrome and each of its individual components across 25OHD tertiles. Multivariable linear regression was used to estimate the adjusted mean difference of insulin secretion and sensitivity across the same 25OHD tertiles. In participants free of metabolic syndrome at baseline (N=546), incident metabolic syndrome in the first 2 years of follow-up was assessed using discrete-time proportional hazards regression to test its association with 25OHD concentration.

RESULTS

After multivariate adjustment, participants in the highest tertile of 25OHD had lower odds of prevalent metabolic syndrome (odds ratio=0.62; 95% confidence interval (CI)=0.45-0.84), smaller waist circumference, higher high-density lipoprotein and lower fasting plasma glucose compared with participants in the lowest tertile of 25OHD. Higher plasma 25OHD concentration was associated with greater insulin sensitivity and lower insulin secretion. After multivariate adjustment, there was a nonsignificant lower risk of metabolic syndrome in the highest tertile of 25OHD (hazard ratio=0.79; 95% CI=0.48-1.32) compared with the lowest tertile.

CONCLUSIONS

In a population at increased risk for diabetes, higher plasma 25OHD concentration was inversely associated with prevalent metabolic syndrome and nonsignificantly with incident metabolic syndrome.

Associations between serum-intact parathyroid hormone, serum 25-hydroxyvitamin D, oral vitamin D analogs and metabolic syndrome in peritoneal dialysis patients: a multi-center cross-sectional study

INTRODUCTION

Although previous studies have suggested associations between serum intact parathyroid hormone (iPTH), 25-hydroxyvitamin D (25(OH)D) and metabolic syndrome (MS) in the general population, these associations are still uncharacterized in peritoneal dialysis (PD) patients.

METHODS

In total, 837 prevalent PD patients from 5 centers in China were enrolled between April 1, 2011 and November 1, 2011. The demographic data, biochemical parameters and medical records were collected, except for serum 25(OH)D which was measured in 347 of 837 patients. The definition of MS was modified from National Cholesterol Education Program Third Adult Treatment Panel (NCEP-ATPIII).

RESULTS

55.4% of 837 patients were found to have MS. The median concentration of iPTH, 25(OH)D and doses of oral vitamin D analogs for participants with MS was significantly lower than those without MS. The iPTH, 25(OH)D values and doses of vitamin D analogs were all associated with one or more components of MS. After multivariate adjustment, low serum iPTH values and oral vitamin D analogs, rather than serum 25(OH)D, were significantly associated with the presence of MS, abnormal fasting blood glucose (FBG) and high-density lipoprotein cholesterol (HDL-C). Compared to iPTH < 130 pg/mL, iPTH 130-585 pg/mL and > 585 pg/mL were associated with a lower risk of MS with adjusted odds ratio (OR) of 0.59 and 0.33, respectively. Taking vitamin D analogs was also associated with a lower risk of MS with adjusted OR of 0.55.

CONCLUSIONS

Serum iPTH and the use of active vitamin D supplements rather than serum 25(OH)D were independently associated with the presence of MS in patients on PD.

25-Hydroxyvitamin D insufficiency is associated with cardiometabolic risk in Korean adolescents: the 2008-2009 Korea National Health and Nutrition Examination Survey (KNHANES)

OBJECTIVE

Vitamin D insufficiency is known to be related to cardiometabolic disorders; however, the associations among serum 25-hydroxyvitamin D (25(OH)D) concentration and metabolic syndrome and cardiometabolic risk factors in children and adolescents have not yet been clearly delineated. For this reason, we investigated the relationship among serum 25(OH)D concentration and metabolic syndrome and cardiometabolic risk factors among Korean adolescents.

DESIGN

We performed a cross-sectional analysis and used hierarchical multivariate logistic regression analysis models to adjust for confounding variables.

SETTING

We used the data gathered during the 2008-2009 Korea National Health and Nutrition Examination Survey (KNHANES).

SUBJECTS

Our subjects included 1504 Korean adolescents aged 12-18 years who participated in the KNHANES.

RESULTS

Vitamin D insufficiency, defined as 25(OH)D concentration <50 nmol/l, was found in 75·3% of Korean adolescents and was associated with an increased risk of the prevalence of metabolic syndrome. Waist circumference and BMI were the most closely correlated cardiometabolic components of metabolic syndrome according to serum 25(OH)D status, but no significant relationship was found between serum 25(OH)D concentration and insulin resistance or for the risks for high blood pressure, hyperglycaemia, reduced HDL-cholesterol or hypertriacylglycerolaemia, with or without adjustment for confounding variables.

CONCLUSIONS

Low serum 25(OH)D concentration appears to be associated with several cardiometabolic risk factors and an increased risk of the prevalence of metabolic syndrome in Korean adolescents.

Low serum vitamin D level is associated with high risk of metabolic syndrome in post-menopausal women

BACKGROUND

Serum vitamin D status, as indicated by 25-(OH)D, is inversely associated with glucose homeostasis, lipid profiles, and blood pressure. Evidence on the association of serum vitamin D with metabolic syndrome (MS) however, is very limited in post-menopausal women.

AIM

To investigate the association between serum vitamin D and MS.

MATERIALS AND METHODS

This study was a crosssectional study including 778 Korean adults who visited a health promotion center in a university hospital from January 2010 to May 2011. MS was defined according to the American Heart Association/National Heart, Lung, and Blood Institute criteria and the Korean Society for the Study of Obesity. MS and its individual components were assessed, as well as serum 25-(OH)D levels with a multiple logistic regression analysis.

RESULTS

The overall prevalence of the MS in participants of this study was 147 (18.9%). After multiple adjustments, compared with the highest quartile serum 25- (OH)D level group (19.9-55.9 ng/ml), the odds ratio for MS in the lowest level group (4.2-9.7 ng/ml) was 2.44 [95% confidence interval (CI)=1.32-4.48], in the lower level group (9.8- 14.1 ng/ml) was 2.20 (95% CI=1.24-3.90), and in the intermediate level group (14.3-19.8 ng/ml) was 1.81 (95% CI=1.02-3.20). Among the components of MS, the adjusted odds ratios for having an elevated blood pressure, and high triglyceride level in the lowest level group were 1.81 (95% CI, 1.15-2.85), 2.74 (95% CI, 1.64-4.57), respectively.

CONCLUSIONS

We found that a low serum 25-(OH)D level is significantly associated with the presence of MS and some metabolic components, especially the high triglyceride level and blood pressure in post-menopausal women.

Serum 25-hydroxyvitamin D, parathyroid hormone, and their association with metabolic syndrome in Chinese

Increasing evidence suggests that 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH) levels are associated with metabolic syndrome (MetS). In 2010, we explored the association of serum 25(OH)D and PTH levels with MetS in 1,390 Chinese participants, aged 20-83 years. Anthropometric phenotypes, blood pressure, and the incidence of MetS were evaluated. In addition, serum lipids, 25(OH)D, and PTH were measured. The median concentration of 25(OH)D and PTH were 55.3 nmol/l and 2.8 pmol/l, respectively. The prevalence of vitamin D deficiency (<50 nmol/l) was 39.9 %, with 34.5 % in men and 47.8 % in women. After accounting for confounding factors and serum PTH, a 10 nmol/l higher serum 25(OH)D level was associated with a 10 % lower risk of MetS (OR = 0.90, 95 % CI 0.84-0.96, P = 0.0007). Furthermore, participants with vitamin D sufficiency had a 35 % lower risk of MetS than those with vitamin D deficiency (OR = 0.65, 95 % CI 0.51-0.84, P = 0.0009). PTH was not associated with the risk of MetS after adjustment for confounding factors. These results were confirmed in both men and women. Thus in this cohort of Chinese individuals, vitamin D deficiency is common and optimal vitamin D level is inversely associated with MetS, independent of several confounders and PTH level. The clinical significance of these findings warrants further study.

Effects of vitamin D(2) supplementation on insulin sensitivity and metabolic parameters in metabolic syndrome patients

BACKGROUND

Vitamin D deficiency has been linked to many of the characteristics of metabolic syndrome, but whether supplementation with vitamin D2 would improve insulin sensitivity or metabolic risk factors is not known.

AIM

To investigate effects of vitamin D2 supplementation on insulin sensitivity and metabolic parameters in metabolic syndrome patients.

SUBJECTS AND METHODS

An 8-week, prospective randomized, double-blind, double-dummy, parallel trial was conducted in patients with metabolic syndrome. Ninety patients were equally randomized to receive vitamin D2 40,000 IU per week, vitamin D2 20,000 IU per week, or placebo. Outcomes were assessed at baseline and at the end of the study.

RESULTS

At week 8, serum 25(OH)D concentrations were increased significantly in both vitamin D2 groups (i.e., 20,000 IU and 40,000 IU) when compared with placebo group (11.72 ng/ml vs 2.80 ng/ml; p<0.001 and 15.74 ng/ml vs 2.80 ng/ml; p<0.001, respectively). Serum 25(OH)D concentrations in both vitamin D2 treatment groups were also significantly different (p=0.04). Insulin sensitivity assessed by homeostasis model assessment of insulin resistance (HOMA-IR) at week 8 in the three groups was not significantly different (p=0.36).

CONCLUSIONS

Vitamin D2 20,000 IU per week and 40,000 IU per week given for 8 weeks, were able to increase serum 25(OH)D concentrations significantly more than placebo group. However, HOMA-IR was not significantly different in the three groups. Our results do not support a positive effect of vitamin D2 on metabolic risk factors.

The role of vitamin D in blood pressure, endothelial and renal function in postmenopausal women

BACKGROUND

Vitamin D is a pro-hormone that plays an essential role in the vasculature and in kidney function.

AIMS

To review the extra-skeletal effects of vitamin D on blood pressure, endothelial and renal function with emphasis on recent findings in postmenopausal women.

METHODS

Included in this review was a PubMed database search for English language articles through March 2013. This review discussed the physiology and definition of vitamin D deficiency, the recent evidence for the role vitamin D in blood pressure, vascular and renal function.

RESULTS

Experimental and epidemiological data suggest that vitamin D plays an important role in the vasculature and in kidney function. Low vitamin D concentrations appear to significantly associate with hypertension, endothelial and renal dysfunction. However, the results of clinical trials have generally been mixed. Studies specifically conducted among postmenopausal women are limited and findings are still inconsistent.

CONCLUSIONS

Definitive studies are warranted to elucidate the effects of vitamin D supplementation on vascular and renal function and a more detailed work is needed to outline the route, duration and optimal dose of supplementation. It is premature to recommend vitamin D as a therapeutic option in the improvement of vascular and renal function at the current stage.

Decreased serum concentrations of 25-hydroxycholecalciferol are associated with increased risk of progression to impaired fasting glucose and diabetes

OBJECTIVE

To study the association between vitamin D status and the risk of incident impaired fasting glucose (IFG) and diabetes in a population-based cohort of diabetes-free subjects.

RESEARCH DESIGN AND METHODS

In a historical prospective cohort study of subjects from the Clalit Health Services database, which includes information on nearly 4 million people, diabetes-free subjects aged 40-70 years with serum 25-hydroxycholecalciferol (25-OHD) measurements available were followed for 2 years to assess the development of IFG and diabetes in five 25-OHD subgroups: ≥25, 25.1-37.5, 37.6-50, 50.1-75, and >75 nmol/L.

RESULTS

The baseline cohort included 117,960 adults: 83,526 normoglycemic subjects and 34,434 subjects with IFG. During follow-up, 8,629 subjects (10.3% of the normoglycemic group) developed IFG, and 2,162 subjects (1.8% of the total cohort) progressed to diabetes. A multivariable model adjusted for age, sex, population group, immigrant status, BMI, season of vitamin D measurement, LDL and HDL cholesterol, triglycerides, estimated glomerular filtration rate, history of hypertension or cardiovascular disease, Charlson comorbidity index, smoking, and socioeconomic status revealed an inverse association between 25-OHD and the risk of progression to IFG and diabetes. The odds of transitioning from normoglycemia to IFG, from normoglycemia to diabetes, and from IFG to diabetes in subjects with a 25-OHD level ≤25 nmol/L were greater than those of subjects with a 25-OHD level >75 nmol/L [odds ratio 1.13 (95% CI 1.03-1.24), 1.77 (1.11-2.83), and 1.43 (1.16-1.76), respectively].

CONCLUSIONS

Vitamin D deficiency appears to be an independent risk factor for the development of IFG and diabetes.

25-hydroxyvitamin D deficiency is associated with an increased risk of metabolic syndrome in patients with non-diabetic chronic kidney disease

Background: Patients with chronic kidney disease (CKD) not requiring dialysis have a high prevalence of 25-hydroxyvitamin D (25(OH)D) deficiency but the relationship between 25(OH)D levels and metabolic syndrome is unknown in this population. Methods: This study analyzed stored plasma samples from 495 non-diabetic subjects with severe kidney disease, not yet on dialysis, who participated in the homocysteine in kidney and end stage renal disease study. Metabolic syndrome was defined as the presence of all three of the following: (1) Serum triglycerides ≥ 150 mg/dl or drug treatment for hypertriglyceridemia; (2) serum high density lipoprotein-cholesterol (HDL-C) < 50 mg/dl for women or < 40 mg/dl for men or drug treatment for dyslipidemia; and (3) blood pressure ≥ 130/85 mmHg or drug treatment for hypertension. Multivariate logistic regression models were used to evaluate the cross-sectional association between plasma 25(OH)D levels and metabolic syndrome. Results: The prevalence of metabolic syndrome increased as 25(OH)D levels declined, with the highest prevalence in participants with 25(OH)D levels < 20 ng/ml. Participants with 25(OH)D levels < 20 ng/ml had a significantly increased risk of metabolic syndrome compared to subjects with levels > 30 ng/ml after adjustment for multiple confounders (OR 2.25, 95% CI 1.25 – 4.07). Plasma 25(OH)D levels were inversely associated with diastolic blood pressure (R = –0.10, p = 0.029) and serum triglyceride levels (R = –0.14, p = 0.002). Conclusion: 25(OH)D deficiency is strongly associated with an increased risk of metabolic syndrome in non-diabetic patients with severe CKD not yet on dialysis, independent of cardiometabolic risk factors and other important regulators of mineral metabolism.

Long-term dietary intake and nutritional deficiencies following sleeve gastrectomy or Roux-En-Y gastric bypass in a mediterranean population

BACKGROUND

Data on long-term dietary changes and nutritional deficiencies after sleeve gastrectomy (SG) in grade 3 obese patients are scarce.

OBJECTIVE

To prospectively compare dietary changes and nutritional deficiencies in grade 3 obese patients 5 years after SG and Roux-en-y gastric bypass (GBP).

PARTICIPANTS/SETTING

Three hundred and fifty-five patients who had SG (n=61) or GBP (n=294) (May 2001-December 2006) at a Spanish university hospital.

DESIGN

Longitudinal, prospective, observational study. PRIMARY OUTCOMES/STATISTICAL ANALYSES: Changes in energy, macronutrient, and micronutrient intake, and weight loss were analyzed using mixed models for repeated measurements.

RESULTS

At the 5-year follow-up visit, the percentage of excess weight loss (P=0.420) and daily energy intake (P=0.826), as well as the proportion of energy from carbohydrates (P=0.303), protein (P=0.600), and fat (P=0.541) did not differ between surgical groups. Energy intake (P=0.004), baseline weight (P<0.001), and time period (P<0.001), but not the proportion of different macronutrients or the type of surgery, independently predicted the percentage excess weight loss over time. After SG or GBP, the mean daily dietary intake of calcium, magnesium, phosphorus, and iron was less than the current recommendations. Despite universal supplementation, the prevalence of nutritional deficiencies was comparable after SG or GBP, with 25-hydroxyvitamin D being the most commonly observed deficiency (SG, 93.3% to 100%; GBP, 90.9% to 85.7%, P=not significant). In an adjusted multivariate regression model, energy intake and lipid intake independently predicted plasma 25(OH)-vitamin D levels.

CONCLUSIONS

Data show that SG and GBP are associated with similar long-term weight loss with no differences in terms of dietary intake. Furthermore, data demonstrate that both types of surgeries carry comparable nutritional consequences.

Plasma vitamin D and parathormone are associated with obesity and atherogenic dyslipidemia: a cross-sectional study

BACKGROUND

Low concentrations of plasma vitamin D (25(OH)D) have been associated with the development of metabolic syndrome (MetS), obesity, diabetes and cardiovascular disease. The objective of this study was to quantify the associations between 25(OH)D and parathormone (PTH) plasma levels and obesity, the presence of MetS, diabetes or atherogenic dyslipidemia (AD) in a large sample of individuals with different degrees of adiposity.

METHODS

Retrospective study of all patients who had attended the obesity clinics in a Spanish hospital between 2009 and 2011, and whose concentrations of PTH, 25(OH)D, calcium and alkaline phosphatase had been determined (n=316, 75.9% women). Individuals were categorized by degree of adiposity, presence of MetS, and other comorbidities.

RESULTS

PTH increased but 25(OH)D and calcium decreased with increasing adiposity. The prevalence of 25(OH)D deficiency or insufficiency increased with obesity (<10% when BMI<45kg/m(2), and 26% when >50). The prevalence of hyperparathyroidism increased from 12% in non-obese to 47.5% in morbidly obese individuals with BMI>50 kg/m2. Low plasma 25(OH)D and high PTH concentrations were associated with an increased risk of MetS and AD. These associations disappeared, except in the case of AD for 25(OH)D when adjusting for BMI. Regression analysis revealed that BMI and age or seasonality were independent predictors of PTH and 25(OH)D levels, respectively.

CONCLUSIONS

BMI was the variable most strongly associated with plasma 25(OH)D and PTH concentrations in our study. Low 25(OH)D and high PTH concentrations were not independently associated with an increased risk of MetS, or diabetes. Our data support a possible contribution of plasma 25(OH)D to the pathogenesis of hypertriglyceridemia and AD through inflammation.

The association of hypovitaminosis d with the metabolic syndrome is independent of the degree of obesity

Background. It remains uncertain whether the metabolic syndrome (MS) or insulin resistance contribute to the association between vitamin D deficiency and obesity. Methods. We conducted a cross-sectional survey of 343 subjects who were overweight or obese. We analyzed anthropometric data and the presence or absence of MS. Additionally, we determined 25-hydroxyvitamin D (25OHD) and insulin concentrations, and the HOMA index was calculated. Chi-square test,Mann-Whitney U test, Student's t-tests,and logistic regression analysis were used. Results. The mean age of the patients was 42 ± 11 years, and 65.9% were women. The mean BMI was 34.7 ± 8.3 kg/m² and 25(OH)D levels were 53.7 ± 29.8 nmol/L. Forty-six patients (13.4%) had MS. Vitamin D status was associated with the degree of obesity, especially with a BMI > 40 kg/m². Patients with MS had lower levels of 25(OH)D than patients without (43.3 ± 29.0 versus 55.3 ± 29.6 mmol/L, resp.), and the odds ratio for hypovitaminosis D was 2.7 (confidence interval (CI), 1.14–6.4) (P = .023) for patients with MS versus patients without MS, irrespective of the degree of obesity. Conclusions. Our data confirm the association between vitamin D and MS and suggest that this association is independent of the degree of obesity.