Serum 25-hydroxyvitamin D concentrations in relation to cardiometabolic risk factors and metabolic syndrome in postmenopausal women

Relationship between Circulating 25-Hydroxyvitamin D and Metabolic Syndrome in Chinese Adults: A Large Nationwide Longitudinal Study

OBJECTIVE

This study investigated the association of circulating levels of 25-hydroxyvitamin D (25[OH]D) with the risk of metabolic syndrome (MetS) and its components in adults.

METHODS

This nationwide cohort involved 23,810 Chinese adults attending annual health evaluations. Serum 25(OH)D levels, MetS status, and covariates were determined at each examination. Among them, 8146, 3310, and 1971 completed two, three, and more than three evaluations, respectively. A hybrid mixed-effects and Cox regression model was employed to determine the cross-sectional and longitudinal relationships.

RESULTS

The odds ratios (ORs) and 95% confidence intervals (CIs) of MetS were significantly lower in individuals within quartile 4 (vs. 1) of serum 25(OH)D for both between-individual (0.43 [0.35, 0.52]) and within-individual comparisons (0.60 [0.50, 0.73]), respectively (all p-trends < 0.001). Among the MetS components, the corresponding ORs (95% CI) in between- and within-individual comparisons were 0.40 (0.29, 0.54) and 0.26 (0.19, 0.36) for abdominal obesity, 0.49 (0.41, 0.58) and 0.78 (0.66, 0.93) for high triglycerides, 0.70 (0.59, 0.82) and 0.75 (0.64, 0.87) for hypertriglyceridemia, 0.48 (0.39, 0.59) and 0.87 (0.71, 1.07) for low HDL cholesterol, and 0.92 (0.76, 1.12) and 0.49 (0.41, 0.59) for hypertension, respectively. Decreased hazard ratios (95% CIs) in quartile 4 (vs. 1) of 25(OH)D were found for MetS (0.80 [0.65, 1.00]), high triglycerides (0.76 [0.62, 0.92]), abdominal obesity (0.77 [0.63, 0.96]), and low HDL cholesterol (0.64 [0.50, 0.81]).

CONCLUSIONS

Decreased concentrations of serum 25(OH)D correlate significantly to a heightened MetS risk and specific components. Our findings underscore the potential preventive function of circulating vitamin D concerning metabolic disorders.

Association between vitamin D deficiency and lipid profiles in overweight and obese adults: a systematic review and meta-analysis

OBJECTIVE

The association between vitamin D deficiency and lipid profiles in adults with overweight or obesity remains unclear and inconsistent. The aim of our study was to determine the relationship between lipid profiles and vitamin D deficiency in the overweight and obese adults.

METHODS

Four databases, including PubMed, the Web of Science, EMBASE and the Cochrane Library, were used to identify all studies on vitamin D status and lipid levels, including the serum levels of triglycerides (TGs), total cholesterol (TC), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL). The Weighted mean difference (WMD) with 95% confidence intervals (CIs) using random-effects models was used to assess the association between the lipid profile and vitamin D deficiency.

RESULTS

Twenty-one articles that included a total of 7952 adults with overweight or obesity (BMI ≥ 25 kg/m2) were included. The overall results revealed that compared with the controls, individuals with vitamin D deficiency showed higher levels of TG (WMD = 15.01; 95%CI, 2.51-27.52) and TC (WMD = 8.61; 95%CI, 1.31-15.92). Moreover, vitamin D deficiency was related to an increased level of LDL (WMD = 6.12; 95%CI, 0.02-12.23). HDL level was inversely associated with the vitamin D deficiency status (WMD = -2.57; 95%CI, -4.26, -0.88).

CONCLUSIONS

Among the adults with overweight or obesity, the vitamin D deficient group displayed impaired lipid profiles, including increased TG, TC and LDL levels and reduced HDL level.

The role of vitamin D in menopausal women's health

Vitamin D (VD) is known to play an important role in the maintenance of calcium homeostasis and bone metabolism. In recent years, there has also been a growing interest in Vitamin D for health issues beyond the bones. Menopausal women are at risk of reduced bone density and increased risk of fracture due to a decline in estrogen levels. There is also an increased risk of cardiovascular disease, diabetes and hyperlipidaemia due to impaired lipid metabolism. The menopausal and emotional symptoms due to menopause are also increasingly prominent. This article summarizes the role of Vitamin D in menopausal women's health, including the effects of Vitamin D on skeletal muscle, cardiovascular disease, Genitourinary Syndrome of Menopause (GSM), cancer and emotional symptoms. Vitamin D regulates the growth of vaginal epithelial cells and alleviates genitourinary tract problems in menopausal women. Vitamin D also modulates immune function and influences the production of adipokines. Vitamin D and its metabolites also have an anti-proliferative effect on tumour cells. This narrative review, by summarizing recent work on the role of Vitamin D in menopausal women and in animal models of menopause, aims to provide a basis for further development of the role of Vitamin D in the health of menopausal women.

Efficacy of vitamin D3 supplementation on cancer mortality: systematic review and individual patient data meta-analysis of randomised controlled trials

To evaluate the effect of vitamin D₃ supplementation on cancer mortality in the general population and on prognosis in cancer patients, a systematic review and meta-analysis of randomised, placebo-controlled trials (RCTs) and individual patient data (IPD) was conducted. Overall, 14 RCTs with a total of 104,727 participants (2,015 cancer deaths) were identified and 7 RCTs, including 90% of all study participants (n=94,068), could be included in the IPD meta-analyses. The main meta-analysis of the 14 RCTs yielded a statistically non-significant reduction in cancer mortality by 6% (risk ratio (RR) [95%-confidence interval (95%CI)]: 0.94 [0.86-1.02]). Subgroup analyses revealed a 12% lower cancer mortality in the vitamin D₃ group compared with the placebo group in 10 trials with a daily dosing regimen (RR [95%CI]: 0.88 [0.78-0.98]), whereas no mortality reduction was seen in 4 trials using a bolus regimen (RR [95%CI]: 1.07 [0.91-1.24]; p-value for interaction: 0.042). The IPD meta-analysis (RR [95%CI]: 0.93 [0.84; 1.02]) confirmed the finding of all trials. The IPD were used to test effect modification by age, sex, body mass index, ethnicity, baseline serum 25-hydroxyvitamin D concentration, adherence and cancer-related factors but no statistically significant findings were obtained in meta-analyses of all trials. When restricted to trials with daily dosing in a post-hoc analysis, adults aged ≥70 years (RR [95%CI]: 0.83 [0.77; 0.98]) and subjects with vitamin D₃ therapy initiation before cancer diagnosis (RR [95%CI]: 0.87 [0.69; 0.99]) appeared to benefit most from daily vitamin D₃ supplementation. Measurements of baseline 25-hydroxyvitamin D levels and inclusion of other than non-Hispanic White adults were too sparse in the trials to draw conclusions. Results for all-cause and cancer-specific survival of participants with cancer were comparable to those obtained in the general population for cancer mortality. In conclusion, vitamin D₃ did not reduce cancer mortality in the main meta-analysis of all RCTs because the observed risk reduction by 6% was not statistically significant. However, a subgroup analysis revealed that vitamin D₃ administered daily, in contrast to bolus supplementation, reduced cancer mortality by 12%.

Effect of Medically Supervised Prolonged Fasting Therapy on Vitamin D, B12, Body Weight, Body Mass Index, Vitality and Quality of Life: A Randomized Control Trial

Background

Recent research indicates prolonged fasting for more than 7 days is beneficial in priming the vitamin D metabolism. However, methodological limitations in previous studies, such as insufficient sample size and a lack of control group, limits its generalizability. The present study evaluated the impact of prolonged fasting (10 days) on vitamin D, vitamin B12, body mass index (BMI), weight, hemoglobin, vitality and quality of life (QoL) compared to a normal diet.

Methods

This randomized control trial was conducted in an in-patient private yoga and naturopathy setting between February and April 2022. A total of 52 participants (mean age 51.57 ± 13.67 years) with varying medical conditions were randomized into a fasting group (FG) or a normal diet group (NDG) with 26 participants in each group. The FG was on a fasting diet (500 kCal/day) which included holy basil herbal tea, lemon honey water, and water (3 L). The NDG (1500 kCal/day) consumed a routine diet that included Indian bread, pulses, steamed rice, vegetable salads, and beverages.

Results

The FG has shown significant increase in the Vitamin D levels (P = .003, d = 0.475), vitality (P = .006, d = 0.425), physical QoL (P < .001, d = 0.549), psychological QoL (P = .002, d = 0.488), and environmental QoL (P = .004, d = 0.457) compared to NDG. No significant changes were observed in vitamin B12, weight, BMI, haemoglobin, and social QoL. A weak to moderate (ρ = 0.330-0.483) positive correlation was observed between vitality scores and QoL domains, whereas BMI scores showed an inverse correlation (ρ = -.280) with vitamin D levels.

Conclusion

The results suggest that prolonged fasting for 10 days can improve vitamin D levels, improve vitality, and promote quality of life compared to a normal diet. Unlike previous studies, the FG does not differ from the NDG concerning weight and BMI. Nevertheless, fasting may be utilized as an effective tool to tackle vitamin D deficiency and associated health insufficiencies.

Hypovitaminosis D and Metabolic Syndrome in Postmenopausal Women

Metabolic syndrome (MetSyn) is a precursor for several cardiometabolic diseases. The prevalence of MetSyn is higher in postmenopausal women compared to premenopausal women. The role of vitamin D in postmenopausal women is not clearly understood. Hypovitaminosis D is more prevalent in postmenopausal women compared to premenopausal women. For this review, Pubmed, Cochrane, SCOPUS, Embase, and Google Scholar databases were searched up to August 2022. Findings from one randomized controlled trial (RCT) and ten cross-sectional studies were included in this review. Several cross-sectional studies (8 out of 10 reviewed) unequivocally demonstrated an inverse association between serum 25-hydroxyvitamin D concentrations and MetSyn. However, RCTs are severely lacking in the effect of vitamin D intake on the biomarkers of MetSyn and the prevalence of MetSyn. Therefore, caution should be used in recommending mega doses of vitamin D supplements for postmenopausal women because of the potential adverse effects associated with this vitamer.

Association between metabolic body composition status and vitamin D deficiency: A cross-sectional study

This study aimed to investigate the risk of vitamin D deficiency in a relatively healthy Asian population, with (i) metabolically healthy normal weight (MHNW) (homeostasis model assessment-insulin resistance [HOMA-IR] < 2. 5 without metabolic syndrome [MS], body mass index [BMI] < 25), (ii) metabolically healthy obesity (MHO) (HOMA-IR < 2.5, without MS, BMI ≥ 25), (iii) metabolically unhealthy normal weight (MUNW) (HOMA-IR ≥ 2.5, or with MS, BMI < 25), and (iv) metabolically unhealthy obesity (MUO) (HOMA-IR ≥ 2.5, or with MS, BMI ≥ 25) stratified by age and sex. This cross-sectional study involved 6,655 participants aged ≥ 18 years who underwent health checkups between 2013 and 2016 at the Chang Gung Memorial Hospital. Cardiometabolic and inflammatory markers including anthropometric variables, glycemic indices, lipid profiles, high-sensitivity C-reactive protein (hs-CRP), and serum 25-hydroxy vitamin D levels, were retrospectively investigated. Compared to the MHNW group, the MHO group showed a higher odds ratio (OR) [1.35, 95% confidence interval (CI) 1.05-1.73] for vitamin D deficiency in men aged < 50 years. By contrast, in men aged > 50 years, the risk of vitamin D deficiency was higher in the MUO group (OR 1.44, 95% CI 1.05-1.97). Among women aged < and ≥ 50 years, the MUO group demonstrated the highest risk for vitamin D deficiency, OR 2.33 vs. 1.54, respectively. Our study revealed that in women of all ages and men aged > 50 years, MUO is associated with vitamin D deficiency and elevated levels of metabolic biomarkers. Among men aged < 50 years, MHO had the highest OR for vitamin D deficiency.

Overview of Nutraceuticals and Cardiometabolic Diseases following Socio-Economic Analysis

The importance of functional food and nutraceutical products to deal with cardiometabolic diseases (CMDs) and metabolic syndrome (MetS) has gained attention in the past few years. The aim of this narrative review is to highlight the potential and effectiveness of nutraceutical in the improvement of CMDs and MetS biomarkers, alongside their burden of disease and economic health expenditure. A science database search was conducted between May and June 2021. A total of 35 studies were included in this paper. We included male and female subjects, children, and adults, in good health or with cardiovascular or metabolic disease. CMDs and MetS have gradually become worldwide health problems, becoming two of the major causes of morbidity and mortality in western countries. The results indicate a positive link between daily consumption of nutraceutical products and an improvement in cardiometabolic and anthropometric biomarkers. In this paper we included a wide range of nutraceutical products. Most of them showed promising data, indicating that nutraceuticals could provide a new therapeutic treatment to reduce prevalence and pharmaceutical expenditures attributed to CMDs and MetS. Unfortunately, there is a huge vacuum of data on nutraceutical usage, savings, and burden reduction. Therefore, further clinical and pharmaco-economic research in the field is highly required.

Adequacy and Vitamin D in the Preoperative Period of Roux-en-Y Gastric Bypass, Bariatric Surgery, Can Protect Metabolic Health in Metabolically Healthy and Unhealthy Individuals

Evaluating the influence of vitamin D concentrations together with preoperative metabolic phenotypes on remission of chronic noncommunicable diseases (CNCDs) after 6 months of Roux-en-Y gastric bypass (RYGB). Cross-sectional analytical study comprising 30 adult individuals who were assessed preoperatively (T0) and 6 months (T1) after undergoing RYGB. Participants were distributed preoperatively into metabolically healthy obese (MHO) and metabolically unhealthy obese (MUHO) individuals according to HOMA-IR classification and to the adequacy and inadequacy of vitamin D concentrations in the form of 25(OH)D. All participants were assessed for anthropometric characteristics, biochemical variables, and presence of CNCDs. The statistical program used was the SPSS version 21. In face of vitamin D adequacy and regardless of the metabolic phenotype classification in the preoperative period, the means found for HOMA-IR allowed us to define them as metabolically healthy 6 months after RYGB. Only those with vitamin D inadequacy with the MUHO phenotype showed better results regarding the reduction of glucose that accompanied the shift in serum 25(OH)D concentrations from deficient to insufficient. It is possible that preoperative vitamin D adequacy, even in the presence of an unhealthy phenotype, may contribute to the reduction of dyslipidemia and improvement in cholesterol. It is suggested that preoperative vitamin D adequacy in both phenotypes may have a protective effect on metabolic health.

The association between serum 25-hydroxyvitamin D concentrations and serum lipids in the Southern Thai population

INTRODUCTION

Dyslipidaemia is a major risk factor for cardiovascular diseases (CVD). Vitamin D deficiency has been found to be associated with CVD. However, the relationships between vitamin D and lipids are inconsistent. The aim of this study was to investigate the relationship between vitamin D status and serum lipids in Southern Thai subjects.

MATERIAL AND METHODS

A total of 726 healthy subjects in Southern Thailand were enrolled in the study. Serum 25-hydroxyvitamin D (25(OH)D), lipid profiles, fasting plasma glucose, anthropometric data, blood pressure, and body composition were measured. The relationship between serum 25(OH)D levels and biochemical data was evaluated by partial correlation and multiple linear regression analyses. The association of serum 25(OH)D levels with dyslipidaemia was analysed using multivariate regression analysis.

RESULTS

Serum 25(OH)D levels were negatively correlated with body mass index (BMI), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and body composition parameters after adjusting for age in women. Multiple linear regression analysis showed that TC and BMI were independent predictors for 25(OH)D concentrations in women. Multivariate logistic regression analysis showed that the odds ratio of hypertriglyceridaemia (OR = 0.51; 95% CI: 0.32-0.80, p = 0.004) and reduced high-density lipoprotein cholesterol (HDL-C) (OR = 0.43; 95% CI: 0.26-0.71, p = 0.001) were significantly lower in vitamin D sufficiency when compared with hypovitaminosis D in women.

CONCLUSIONS

Vitamin D sufficiency could reduce risk of hypertriglyceridaemia and reduced HDL-C, particularly in women, suggesting that vitamin D sufficiency may have beneficial effects on lipids and a decreased risk for CVD in Thai women.

Outcomes of a Medically Supervised Fasting Module on Healthy Females in a Controlled Residential Environment: A Brief Report

Background:

Fasting is being used as a therapeutic and cultural practice for millennia. There are numerous reports available on beneficial effects of fasting on various disease conditions. Despite the mounting evidence on fasting, little is known on its physiological effects in humans as most of the studies on physiological effects are done in animals.

Methods:

Twenty healthy female volunteers (mean age ± SD, 21.95 ± 2.52 years) participated in a 10-day fasting program, which has 1 preparatory day and 1 refeeding day (1,000 kcal) and 8 fasting days (500 kcal). All the participants consented to participate in the study. Blood parameters like complete blood count, renal function test, total iron binding capacity, lipid profile, liver profile, vitamins D and B12, thyroid function tests, glycated hemoglobin, and air blood gas test along with anthropometric measurements were taken on the first and last day.

Results:

All the parameters under the study have shown statistically significant changes (p < 0.05) except hemoglobin (p = 0.7) and non-high density lipoprotein (p = 0.32). Notable changes were the significant increase in vitamins D and B12 levels that signifies the homoeostatic potential of a fasting regimen.

Conclusion:

The result depicts the positive impact of fasting on various physiological parameters that warrants further studies on the safety of fasting in diverse diseases, especially the ones that have metabolic disarray as the root cause. Despite the limitation of the smaller sample size and lack of a control group, the results are encouraging to devise disease-specific fasting programs.

Vitamin D Deficiency Is Inversely Associated with Homeostatic Model Assessment of Insulin Resistance

The study was conducted to comprehensively assess the association of the concentration of vitamin D in the blood and insulin resistance in non-diabetic subjects. The objective was to pool the results from all observational studies from the beginning of 1980 to August 2021. PubMed, Medline and Embase were systematically searched for the observational studies. Filters were used for more focused results. A total of 2248 articles were found after raw search which were narrowed down to 32 articles by the systematic selection of related articles. Homeostatic Model Assessment of Insulin Resistance (HOMAIR) was used as the measure of insulin resistance and correlation coefficient was used as a measure of the relationship between vitamin D levels and the insulin resistance. Risk of bias tables and summary plots were built using Revman software version 5.3 while Comprehensive meta-analysis version 3 was used for the construction of forest plot. The results showed an inverse association between the status of vitamin D and insulin resistance (r = -0.217; 95% CI = -0.161 to -0.272; p = 0.000). A supplement of vitamin D can help reduce the risk of insulin resistance; however further studies, like randomized controlled trials are needed to confirm the results.

Total, Bioavailable, and Free 25-Hydroxyvitamin D Equally Associate with Adiposity Markers and Metabolic Traits in Mexican Adults

Epidemiological studies suggest a relationship between total 25-hydroxyvitamin D [25(OH)D], adiposity, and metabolic traits. The bioavailability of 25(OH)D is regulated by the albumin, vitamin D binding protein (VDBP), and variants of the GC gene. Therefore, it is not clear if bioavailable or free 25(OH)D offer additional benefits compared to total 25(OH)D when estimating the magnitude of these associations. Our aim was to evaluate the association between 25(OH)D (total, free and bioavailable) with adiposity and metabolic traits. This was a cross-sectional study of 1904 subjects from the Health Workers Cohort Study from Mexico. Free and bioavailable 25(OH)D were calculated based on VDBP and albumin determinations, using a formula adjusted for the GC gene diplotypes. Adiposity and metabolic traits were measured with standardized procedures. Free and bioavailable 25(OH)D levels correlated with total 25(OH)D, r = 0.71 and 0.70, respectively (p < 0.001). Total, bioavailable and free 25(OH)D levels were negatively associated with the adiposity marker (visceral adiposity index) and metabolic traits (metabolic syndrome, type 2 diabetes, triglycerides, triglycerides/HDL-c ratio, and triglycerides/glucose index) in multivariate regression models (ORs = 0.73 to 0.96). Our findings suggest that free and bioavailable 25(OH)D do not offer additional advantages over total 25(OH)D regarding its association with adiposity and several metabolic traits in Mexican adults.

Serum 25-hydroxyvitamin D and Metabolic Parameters in Healthy Korean Adults: Korean National Health and Nutrition Examination Survey VI

Purpose

Studies investigating the association between vitamin D and metabolic parameters have reported inconsistent results depending on the characteristics of the subjects. We aimed to investigate the association between vitamin D levels and various metabolic indicators in healthy Korean adults by using nationally representative data.

Methods

A total of 3640 participants were included after excluding subjects who were ≤19 years of age and had a history of treatment for dyslipidemia, hypertension, or diabetes and a history of other chronic diseases such as liver and kidney diseases. After dividing the 25-hydroxyvitamin D (25(OH)D) level into quartiles, the risk of having each metabolic parameter higher than the median value was determined according to the 25(OH)D quartile by using regression analysis.

Results

In a multivariate regression analysis, a higher 25(OH)D quartile tended to have a significantly lower risk of having a triglyceride (TG) level higher than the median value (103.1 mg/dl). As the quartile increased, the risk of having a waist circumference or body mass index higher than the median value also decreased, but the difference was not statistically significant. No significant changes were observed in fasting glucose or glycated hemoglobin level according to quartile.

Conclusion

We demonstrated that subjects with a higher 25(OH)D quartile exhibited a significantly lower risk of having a TG level higher than the median value in a representative Korean population. More evidence from a prospective study on whether vitamin D supplementation improves serum TG levels in healthy adults is needed.

Serum 25-hydroxyvitamin D concentrations are inversely associated with body adiposity measurements but the association with bone mass is non-linear in postmenopausal women

Vitamin D deficiency has been linked to increased adiposity and decreased bone density. It is not known if vitamin D is linked to adiposity measures and bone mass in postmenopausal Qatar women. We investigated an association between serum vitamin D [25-hydroxyvitmain D (25(OH)D)] and adiposity measurements in postmenopausal women using Qatar Biobank data (n = 935). The post-menopausal status was self-reported by participants. Multivariate adjusted regression was applied to determine the association between serum 25(OH)D and body adiposity markers and bone mass. Serum 25(OH)D was significantly, inversely associated with body mass index (p < 0.0005), waist circumference (0.044), fat mass (p < 0.003), gynoid fat (p < 0.001), and android fat (p < 0.009). Serum 25(OH)D appeared to have an inverse 'U' association with several adiposity measures. Overall, body adiposity markers were the lowest in the 4^th quartile serum 25(OH)D and significantly lower compared to the 1^st quartile serum 25(OH)D. In multivariable adjusted analysis, no association was found between serum 25(OH)D concentration and bone mass when serum 25(OH)D was categorized. In a continuous variable analysis, the association between 25(OH)D and bone mass was significant, non-linear, inverse 'U'. In conclusion, serum 25-hydroxyvitamin D was inversely associated with adiposity measures and non-linearly associated to bone mass in postmenopausal Qatari women.

Insulin Resistance Is Inversely Associated with the Status of Vitamin D in Both Diabetic and Non-Diabetic Populations

Vitamin D has been implicated in the regulation of glucose metabolism and insulin resistance. We designed this study to provide evidence that insulin resistance is dependent on the concentration of vitamin D in the body. Forty observational studies of both type 2 diabetes mellitus patients and healthy subjects were included in this meta-analysis. Related articles were searched from Embase, PubMed, and Medline through January 2021. Filters for search were used to obtain more focused results. We used Comprehensive Meta-Analysis Version 3 for the construction of forest plots. RevMan software version 5.3 was used to build the risk of bias tables and summary plots. The observational studies included in this systematic review and meta-analysis showed an inverse relationship of insulin resistance with the status of vitamin D both in non-diabetic (r = -0.188; 95% CI = -0.141 to -0.234; p = 0.000) and diabetic (r = -0.255; 95% CI = -0.392 to -0.107, p = 0.001) populations. From the meta-analysis we concluded that hypovitaminosis D is related to increased levels of insulin resistance in both type 2 diabetes patients and the healthy population all over the world.

Dose-response relationship between serum 25-hydroxyvitamin D and the risk of metabolic syndrome

BACKGROUND & AIMS

There are conflicting results for the association of 25-hydroxyvitamin D [25(OH)D] with metabolic syndrome (MetS). The aim of this study was to investigate the relationship between serum 25(OH)D concentration and MetS and its components in a Chinese adult population.

METHODS

A cross-sectional study of 25,691 men and 22,146 women from China was performed in 2017. MetS was defined according to National Cholesterol Education Program Adult Treatment Panel Ш. Logistic and restricted cubic spline regression analyses were used to assess the association between 25(OH)D and MetS.

RESULTS

Of the 43,837 participants aged 18-96 years, the prevalence of MetS was 21.0%. The adjusted odds ratios (ORs) for MetS decreased gradually with increasing 25(OH)D concentrations (P for trend < 0.001). Compared with the lowest 25(OH)D quartile, the adjusted ORs (95% CIs) for MetS from second to the highest quartile were 0.95 (0.88-1.02), 0.82 (0.76-0.88), and 0.70 (0.65-0.75), respectively. We observed a linear dose-response relationship between 25(OH)D concentrations and MetS risk (P for nonlinear trend = 0.35); the risk of MetS decreased by 20% (OR = 0.80, 95%CI: 0.77-0.82) for each 10 ng/ml increment in 25(OH)D concentration. The inverse association was more evident in men and participants with eGFR <60 ml/min/1.73 m² or AST ≥40 U/L (all P for interaction < 0.05). Moreover, significant inverse relationships were observed between 25(OH)D and elevated triglycerides, reduced high-density lipoprotein cholesterol and elevated blood pressure.

CONCLUSIONS

These findings suggested that higher 25(OH)D concentrations were independently associated with a dose-response decreased risk of MetS among Chinese adults.

Sex-Specific Association between Serum Vitamin D Status and Lipid Profiles: A Cross-Sectional Study of a Middle-Aged and Elderly Chinese Population

Studies have shown that vitamin D status might be associated with dyslipidaemia, but results are conflicting and there might exist sex differences. The aim of our study was to explore the sex-specific association between vitamin D status and serum lipids and atherogenic index of plasma (AIP, a predictor for atherosclerosis) among Chinese middle-aged and elderly adults. A total of 4,021 middle-aged and elderly participants from a health management centre were included in this cross-sectional study. The individuals were classified into tertiles according to serum 25(OH)D. Linear and logistic regression models were used to estimate the association between vitamin D levels and serum lipids among the tertiles. The mean serum 25(OH)D level was 21.60 (16.60-27.20) ng/mL in all participants. After adjusting for potential confounders, a 10 ng/mL increase in 25(OH)D was associated with decreases of 1.156 mmol/L in triglycerides (TGs) and 0.068 in the AIP and an increase of 0.051 mmol/L in high-density lipoprotein cholesterol (HDL-C) in all subjects. In addition, 25(OH)D deficiency was associated with an increased prevalence of hypertriglyceridaemia (odds ratio (OR), 1.880; 95% confidence interval (CI), 1.351-2.615), hypoalphalipoproteinaemia/HDL (OR, 1.505; 95% CI, 1.146-1.977) and abnormal AIP (OR, 1.933; 95% CI, 1.474-2.534) in males, and 25(OH)D-deficient women had a 2.02-fold higher risk for hypoalphalipoproteinaemia/HDL than women with sufficient 25(OH)D levels (95% CI, 1.044-3.904; all p values <0.05). Vitamin D deficiency was positively associated with the prevalence of dyslipidaemia and abnormal AIP in the middle-aged and elderly Chinese population. And this association was stronger in men than in women.

Serum vitamin D status and metabolic syndrome: a systematic review and dose-response meta-analysis

BACKGROUD/OBJECTIVES

Evidence has suggested an association between serum vitamin D and metabolic syndrome (MetS), but prospective studies are very limited. The objective was to assess the dose-response association between serum vitamin D concentration and MetS risk using a systematic review and meta-analysis of updated observational studies.

MATERIALS/METHODS

Using MEDLINE, PubMed, and Embase, a systematic literature search was conducted through February 2020 and the references of relevant articles were reviewed. A random-effects model was used to estimate the summary odds ratio/relative risk and 95% confidence interval (CI). Heterogeneity among studies was evaluated with I² statistic. In total, 23 observational studies (19 cross-sectional studies, and four cohort studies) were included in the meta-analysis.

RESULTS

The pooled estimates (95% CI) for MetS per 25-nmol/L increment in serum vitamin D concentration were 0.80 (95% CI, 0.76–0.84; I² = 53.5) in cross-sectional studies, and 0.85 (95% CI, 0.72–0.98; I² = 85.8) in cohort studies. Similar results were observed, irrespectively of age of study population, study location, MetS criteria, and adjustment factors. There was no publication bias for the dose-response meta-analysis of serum vitamin D concentrations and MetS.

CONCLUSIONS

Dose-response meta-analysis demonstrated that a 25-nmol/L increment in the serum vitamin D concentration was associated with 20% and 15% lower risks of MetS in cross-sectional studies and cohort studies, respectively.

Association of 25-hydroxyvitamin D levels and metabolic syndrome in Thai postmenopausal women

BACKGROUND AND AIMS

Low serum 25-hydroxyvitamin D [25(OH)D] levels have been reported to be associated with metabolic syndrome (MetS). In this study, we aimed to investigate the association between serum 25(OH)D levels and MetS in Thai postmenopausal women.

METHODS

A total of 340 postmenopausal women were enrolled in the study. The concentration of 25(OH)D, lipid profiles, fasting blood glucose (FBG) levels, blood pressure, and demographic and anthropometric parameters were measured. Subjects were divided into the hypovitaminosis D and vitamin D sufficiency groups. The association of serum 25(OH)D levels with MetS in postmenopausal women was analyzed using multivariate regression analysis.

RESULTS

Waist circumference, total cholesterol levels, and triglyceride levels were significantly higher in hypovitaminosis D than in vitamin D sufficiency (p < 0.05). The prevalence of MetS, central obesity, and hypertriglyceridemia in hypovitaminosis D was significantly higher than in vitamin D sufficiency (p < 0.05). In the multivariable logistic regression model, hypovitaminosis D was associated with MetS (OR 1.85; 95% CI 1.12-3.04, p = 0.015), central obesity (OR 2.41; 95% CI 1.20-4.85, p = 0.014), and hypertriglyceridemia (OR 1.91; 95% CI 1.12-3.26, p = 0.018) compared with vitamin D sufficiency after adjusting for covariates. Serum vitamin D concentrations were significantly lower in the MetS group than in the non-MetS group (p = 0.016) and decreased with an increasing number of MetS components (p for trend = 0.034).

CONCLUSIONS

Hypovitaminosis D was associated with an increased risk of MetS, central obesity, and hypertriglyceridemia in Thai postmenopausal women.

The synergistic effects of vitamin D and estradiol deficiency on metabolic syndrome in Chinese postmenopausal women

OBJECTIVE

Recent studies show that vitamin D (VitD) deficiency is associated with metabolic syndrome (MetS). Current evidence suggests that estrogen and VitD have similar physiological functions and potentially interact with bone health. We investigated the association between estradiol (E2) and 25-hydroxyvitamin-D [25(OH)D] with MetS and its components in Chinese postmenopausal women.

METHODS

In this cross-sectional study, we examined 616 postmenopausal women (aged 49-86 y) from southern China who were not taking estrogen and VitD/calcium supplements. At the end of data collection, serum E2 and 25(OH)D were measured for each participant. MetS was defined according to the 2006 International Diabetes Federation standard.

RESULTS

There was a positive correlation between 25(OH)D and E2. Higher 25(OH)D was associated with a favorable lipid profile, blood pressure, and glucose level. E2 was negatively associated with cholesterol, triglycerides, and blood pressure. The odds ratio for MetS was 2.19 (95% CI, 1.19-4.01, P value for trend=0.009) for deficient compared with sufficient women after multivariable adjustment. This association remained unchanged after further adjusting for E2 levels. After stratified analysis by VitD status, low E2 increased MetS risk in women with VitD deficiency (odds ratio = 3.49, 95% CI, 1.45-8.05 for the lowest vs the highest tertile).

CONCLUSIONS

These results suggest a synergistic role of VitD and E2 deficiency in MetS in Chinese postmenopausal women.

Nutritional assessment among adult patients with suspected or confirmed active tuberculosis disease in rural India

OBJECTIVES

Our study goal was to evaluate a set of nutritional indicators among adults with confirmed or suspected active tuberculosis disease in southern India, given the limited literature on this topic. Study objectives were to assess the: I) double burden of malnutrition at individual and population levels; II) relative performance of anthropometric indicators (body mass index, waist circumference) in diabetes screening; and III) associations between vitamin D and metabolic abnormalities.

DESIGN

Cross-sectional study.

SETTING

Hospital in rural southern India.

PARTICIPANTS

Among adult patients (n = 834), we measured anthropometry, body composition, and biomarkers (vitamin D, glycated hemoglobin, hemoglobin) of nutritional status. Subsets of participants provided blood and sputum samples.

RESULTS

Among participants, 91.7% had ≥ 1 malnutrition indicator; 34.6% had both undernutrition and overnutrition indicators. Despite the fact that >80% of participants would be considered low-risk in diabetes screening based on low body mass index and waist circumference, approximately one-third had elevated glycated hemoglobin (≥ 5.7%). The lowest quintile of serum 25-hydroxyvitamin D was associated with an increased risk of glycated hemoglobin ≥ 5.7% (adjusted risk ratio 1.61 [95% CI 1.02, 2.56]) compared to the other quintiles, adjusting for age and trunk fat.

CONCLUSIONS

Malnutrition and diabetes were prevalent in this patient population; since both can predict poor prognosis of active tuberculosis disease, including treatment outcomes and drug resistance, this emphasizes the importance of dual screening and management of under- and overnutrition-related indicators among patients with suspected or active tuberculosis disease. Further studies are needed to determine clinical implications of vitamin D as a potential modifiable risk factor in metabolic abnormalities, and whether population-specific body mass index and waist circumference cut-offs improve diabetes screening.

Association between Body Fatness and Vitamin D3 Status in a Postmenopausal Population

Vitamin D is a micronutrient that plays a key role in phosphocalcic metabolism. The postmenopausal population presents a risk of deficiency in this vitamin due to hormonal alterations which, in the case of obesity, would be exacerbated. The objective was to assess the status of vitamin D in a postmenopausal population and determine the relationship of 25-hydroxivitamin D [25(OH)D] and its metabolites with anthropometric parameters. The study included 78 healthy postmenopausal women aged from 44 to 76. The nutrient intake assessment was carried out using the 24 h reminder (R24h). 25(OH)D was analyzed using ultra-high-performance liquid chromatography (UHPLC). A total of 80% and 68% of the women studied did not reach sufficient values of 25(OH)D and 25-hydroxivitamin D₃ [25(OH)D₃], respectively, which was inversely correlated with Body Mass Index (BMI) (r = −0.25, p = 0.04), hip perimeter (r = −0.26 and r = −0.24, all p < 0.05), arm circumference (r = −0.29, p = 0.01) and fat mass (r = −0.28 and r = −0.26, all p < 0.05). 25(OH)D₃ is the metabolite that contributed most to this association. In conclusion, 25(OH)D₃ levels are related to anthropometric parameters in the postmenopausal women in this study, confirming insufficient status in the majority of the population. Approach strategies are necessary to correct and avoid this risk in order to ensure future quality of life.

Menopause-Associated Lipid Metabolic Disorders and Foods Beneficial for Postmenopausal Women

Menopause is clinically diagnosed as a condition when a woman has not menstruated for one year. During the menopausal transition period, there is an emergence of various lipid metabolic disorders due to hormonal changes, such as decreased levels of estrogens and increased levels of circulating androgens; these may lead to the development of metabolic syndromes including cardiovascular diseases and type 2 diabetes. Dysregulation of lipid metabolism affects the body fat mass, fat-free mass, fatty acid metabolism, and various aspects of energy metabolism, such as basal metabolic ratio, adiposity, and obesity. Moreover, menopause is also associated with alterations in the levels of various lipids circulating in the blood, such as lipoproteins, apolipoproteins, low-density lipoproteins (LDLs), high-density lipoproteins (HDL) and triacylglycerol (TG). Alterations in lipid metabolism and excessive adipose tissue play a key role in the synthesis of excess fatty acids, adipocytokines, proinflammatory cytokines, and reactive oxygen species, which cause lipid peroxidation and result in the development of insulin resistance, abdominal adiposity, and dyslipidemia. This review discusses dietary recommendations and beneficial compounds, such as vitamin D, omega-3 fatty acids, antioxidants, phytochemicals—and their food sources—to aid the management of abnormal lipid metabolism in postmenopausal women.

Assessment of Subclinical Atherosclerosis in Vitamin D Deficiency

PURPOSE

Patients with vitamin D deficiency (VDD) have potential to have increased cardiovascular morbidity and mortality. In this study, we aimed to discover the findings of early atherosclerosis in patients with VDD by measuring carotid intima-media thickness (CIMT) and epicardial fat thickness (EFT).

MATERIALS AND METHODS

The study population includes 52 patients with VDD (n = 30 [57% female], mean ± SD age 54.28 ± 8.77 years, mean ± SD serum 25-hydroxyvitamin D (25 [OH] D) 11 ± 2.4 ng/mL) and 82 participants for control group (n = 52 [63.4% female], mean ± SD age 56.40 ± 7.90 years, mean ± SD serum (25 [OH] D) 53 ± 4.2 ng/mL) who have no cardiovascular disease. Carotid intima-media thickness was assessed by using ultrasonography, and EFT was measured on the free wall of the right ventricle at end diastole from the parasternal long-axis views by standard transthoracic 2-dimensional echocardiography.

RESULTS

Both CIMT and EFT were significantly higher in patients with VDD compared with controls (0.75 ± 0.16 mm vs 0.68 ± 0.21 mm, P < 0.05, and 0.66 ± 0.15 cm vs 0.56 ± 0.15 cm, P < 0.001).

CONCLUSIONS

Patients with VDD seem to have increased CIMT and EFT, which are predictors of atherosclerotic process. Further studies are needed to confirm these results.

Association between serum 25-hydroxyvitamin D concentrations and metabolic syndrome in the middle-aged and elderly Chinese population in Dalian, northeast China: A cross-sectional study

AIMS/INTRODUCTION

To investigate the association between serum 25-hydroxyvitamin D (25-[OH]D) concentrations and metabolic syndrome (MetS) in the middle-aged and elderly Chinese population.

METHODS

The present study included 2,764 participants (aged >50 years). The joint interim statement was used for the standard definition of MetS. Serum 25-(OH)D concentrations were measured by electrochemiluminescence immunoassay. The study participants were categorized into quartiles based on serum 25-(OH)D concentrations, and the quartiles were calculated for the differences using anova and the χ2 -test for continuous and categorical data, respectively. A logistic regression analysis model was applied to estimate the odds ratios and 95% confidence intervals (95% CI) for each quartile of serum 25-(OH)D concentrations compared with the highest quartile.

RESULTS

Serum 25-(OH)D levels were markedly lower in men in the MetS group than in those without MetS. We observed a negative correlation between the higher quartiles of serum 25-(OH)D levels and the presence of MetS among men. The correlation between serum 25-(OH)D levels and the prevalence of MetS persisted even after adjusting for potential confounders, including age, cigarette smoking status, alcohol consumption, physical activity, low-density lipoprotein, creatinine and total serum cholesterol. Adjusted odds ratios of MetS in the second through fourth compared with the lowest quartile for serum 25-(OH)D levels were 0.93 (95% CI 0.54-1.59), 0.89 (95% CI 0.50-1.56) and 0.48 (95% CI 0.28-0.84), respectively.

CONCLUSIONS

Decreased serum 25-(OH)D level is significantly correlated with MetS in middle-aged men.

Association of 25-hydroxyvitamin D with cardiometabolic risk factors and metabolic syndrome: a mendelian randomization study

Background

Low circulating vitamin D levels have been associated with increased risk of metabolic syndrome (MS) and cardiometabolic risk factors in multiple epidemiology studies. However, whether this association is causal is still unclear. We aimed to test whether genetically lowered vitamin D levels were associated with MS and its metabolic traits, using mendelian randomization (MR) methodology.

Methods

Ten thousand six hundred fifty-five participants were enrolled from the SPECT-China study, which was performed in 23 sites in East China during 2014 to 2016. Using four single-nucleotide polymorphisms (SNPs) in the DHCR7, CYP2R1, GC and CYP24A1 genes with known effects on 25(OH) D concentrations, we created a genetic risk score (GRS) as instrumental variable (IV) to estimate the effect of genetically lowered 25(OH) D on MS and cardiometabolic risk factors. MS was defined according to the International Diabetes Federation criteria.

Results

Lower measured 25(OH)D levels were associated with MS (OR 0.921, 95% CI 0.888, 0.954) after multivariable adjustment. However, the MR-derived odds ratio of genetically determined 25(OH) D for risk of MS was 0.977 (95% CI 0.966, 1.030). The MR-derived estimates for raised fasting plasma glucose was 0.578 (95% CI 0.321, 0.980) per 10 nmol/L GRS_synthesis determined increase of 25(OH) D levels.

Conclusions

We found no evidence that genetically determined reduction in 25(OH)D conferred an increased risk of MS and its metabolic traits. However, we created our GRS only on the basis of common variants, which represent limited amount of variance in 25(OH)D. MR studies using rare variants, and large-scale well-designed RCTs about the effect of vitamin D supplementation on MS are warranted to further validate the findings.

Antifibrotic Effects of 1,25(OH)2D3 on Nonalcoholic Steatohepatitis in Female Mice

BACKGROUND

Postmenopausal women have a higher risk of nonalcoholic steatohepatitis (NASH) along with an increase in age, and vitamin D deficiency occurs in some patients with NASH.

AIM

We performed ovariectomy (OVX) surgery on female mice to mimic menopause, fed them a choline-deficient high-fat (CDHF) diet to induce NASH, and then investigated the effects of treatment with 1,25(OH)₂D₃.

METHODS

Seven-week-old C57BL/6J female mice were separated into five experimental groups: SHAM, OVX, and OVX + intraperitoneal (i.p.) injection of 1,25(OH)₂D₃ (0.0008, 0.004, and 0.02 μg/kg). All groups were fed a CDHF diet for 8 weeks. Injections took place twice per week throughout the experimental period. Blood samples and liver tissue were collected for analyzing liver histological changes, serum biochemical indicators of hepatic function, and hepatic genes associated with fibrosis.

RESULTS

Supplementation of 1,25(OH)₂D₃ in CDHF-diet mice showed decreased serum levels of ALT, AST, indicating the improvement in overall liver function, and suppressed histological NASH regarding fibrosis stage, lobular inflammation, and steatosis compared to the OVX group. Primary fibrotic markers of TGF-β, TIMP-1, α-SMA, and COL1A1 were significantly lower in the 1,25(OH)₂D₃ groups than in the OVX group. Furthermore, down-regulated levels of SMAD2 and SMAD3 were also observed in 1,25(OH)₂D₃ groups.

CONCLUSION

Supplementation of 1,25(OH)₂D₃ may ameliorate liver fibrosis and improve liver function in OVX mice with NASH induced by a CDHF diet, suggesting the therapeutic effects on postmenopause with NASH.

Vitamins in diet of patients with metabolic syndrome

Aim - analysis of data on the role of vitamin and carotenoid deficiency in the development of metabolic syndrome (MS), the consumption of individual vitamins and vitamin supplements, as well as estimation of the effectiveness of the use of vitamins in patients with MS. A review of the existing literature has been carried out in the databases of RINC, CyberLeninka, Google Scholar, Pubmed. The lack of vitamins is a risk factor for MS and its components. The diet of people with MS is characterized by excessive caloric content and at the same time contains an inadequate amount of most vitamins. The most frequent in patients with MS is the deficiency (blood level) of vitamin D, E, B vitamins, carotenoids. Among patients with MS, individuals with a reduced concentration of vitamins in the blood plasma are often found. In turn, among those with a deficiency of vitamins, MS is more often found. Low concentrations of 25(OH)D in the serum are associated with an increased risk of MS. An inverse association between the concentration of the hormonal form of vitamin 1.25(OH)2D3 in the serum and the development of MC has been found. In patients with MS, the α-tocopherol concentration associated with lipids is lower than in healthy individuals, and γ-tocopherol, on the contrary, is higher. Taking high doses of one of the vitamin E homologues shifts the balance between tocopherols in the blood plasma. Sufficient supply of the body with all vitamins involved in the formation of metabolically active forms of vitamins (D, B6, PP) is a necessary condition for the exercise of these biological functions by these vitamins. The lack of vitamins is a risk factor for MS and its components. Enrichment of the diet of patients with MS should be considered as a necessary favorable background for its treatment. Since the body has functional connections between vitamins, it is advisable to use not individual vitamins, but their complexes.

Vitamin D Deficiency is not Associated with Fatty Liver in a Mexican Population

INTRODUCTION AND AIM

Association of vitamin D deficiency (VDD) with fatty liver (FL) disease is controversial. The purpose of this study was to analyze the association of VDD with FL.

MATERIAL AND METHODS

Cross-sectional study. Data on cardiovascular risk factors, medications, alcohol intake, smoking, diet, and physical activity were obtained. Biochemical, anthropometric, and blood pressure variables were measured. The 25-hydroxyvitamin D (25(OH)D) was quantified through chemoluminescence. The presence of FL, defined as a liver/spleen attenuation index lower than 1.0, was identified through computed axial tomography (CAT).

RESULTS

The study included 1,467 subjects (49.7% men) with a mean age of 53.3 ± 9.3 years and BMI of 28.3 ± 4.0 kg/m2. Only 11% had optimum values of vitamin D, and 25(OH)D concentration was lower in participants with FL. Multivariate logistic regression models, adjusted for age, gender, BMI, sampling season, glucose, total cholesterol, triglycerides, HOMA-IR, hs-CRP, ALT, AST, and elevated VAT, revealed an association between FL and vitamin D (VD) insufficiency (RM 1.61 [0.99-2.61]) and with VDD (RM 1.68 [1.02-2.77]); however, statistical significance was lost when including caloric consumption and physical activity in the model.

CONCLUSIONS

In Mexican adults, deficient VD concentration and FL were not independently associated of caloric consumption and physical activity.

Body composition and nutritional and metabolic parameters in postmenopausal women sufficient, insufficient and deficient in vitamin D

OBJECTIVE

We investigated changes in body composition and nutritional and metabolic parameters in a group of postmenopausal women who were classified as sufficient, insufficient and deficient in vitamin D.

SUBJECTS AND METHODS

A total of 106 postmenopausal women were included in this cross-sectional study and classified according to their serum levels of 25-OH-vitamin D as sufficient (≥ 30 ng/mL; group S), insufficient (20.1 and 29.9 ng/mL; group I) or deficient (≤ 20 ng/mL; group D) in vitamin D. Body composition was measured by dual-energy X-ray absorptiometry (DXA); dietary recall questionnaires were completed; and blood samples were analysed to compare the metabolic and nutritional status of the study groups.

RESULTS

Eleven (10.4%) of the women were classified in group S, 50 (47.2%) in group I and 45 (42.4%) in group D, with a mean serum level for 25-OH-D of 21.1 ± 7.0 ng/mL in all participants. Body composition did not differ among the groups. Serum levels of 25-OH-D were negatively correlated with serum levels of triglycerides, total cholesterol and LDL cholesterol.

CONCLUSIONS

Vitamin D insufficiency and deficiency were highly prevalent in our group of postmenopausal women, showing an association with an unfavourable lipid profile.

Relationships between Vitamin D₃ and Metabolic Syndrome

The growing number of overweight and obese individuals is an alarming global problem; these conditions are risk factors for the development of health problems such as metabolic syndrome (MetS), type-2 diabetes, atherosclerosis, and cardiovascular disease. Numerous studies have suggested that vitamin D₃ deficiency plays a role in the pathogenesis of MetS. The aim of this study was to analyze the relationship between MetS and vitamin D₃ levels in women. Laboratory analysis demonstrated that only 26.89% of the participants had vitamin D₃ levels close to normal, and waist-to-hip ratio (WHR) measurements revealed android obesity in 75.63% of the women. The menstruating women more often suffered from vitamin D₃ deficiency, and less often had elevated vitamin D₃ levels. The conclusions are as follows: (1) There were no statistically significant relationships between vitamin D₃ levels and MetS parameters, namely the level of triglycerides, the levels of low- and high-density lipoproteins (LDL and HDL), the level of total cholesterol, and systolic and diastolic blood pressure (SBP and DBP). Vitamin D deficiency was only observed in the women with abdominal obesity. (2) Low vitamin D₃ levels were typical of perimenopausal women. Age was a variable correlating with vitamin D. (3) The presence of menstrual cycles was an important contributor to vitamin D levels. Vitamin D deficiency was significantly more common in the menstruating women.

Body Mass Index, Vitamin D, and Type 2 Diabetes: A Systematic Review and Meta-Analysis

The deficiency of vitamin D is prevalent all over the world. Studies have shown that vitamin D may play an important role in the development of obesity. The current study was conducted to quantitatively evaluate the association between serum 25-(OH) vitamin D levels and the risk of obesity in both diabetic and non-diabetic subjects. A systematic review and meta-analysis of observational studies was carried out for that purpose. We searched the Medline, PubMed, and Embase databases throughout all of March 2018. A total of fifty five observational studies for both diabetic and non-diabetic subjects were finally included in the meta-analysis. The data were analyzed by comprehensive meta-analysis software version 3 and the random effects model was used to analyze the data. The meta-analysis showed an overall inverse relationship between serum vitamin D status and body mass index (BMI) in studies of both diabetic (r = −0.173, 95% = −0.241 to −0.103, p = 0.000) and non-diabetic (r = −0.152, 95% = −0.187 to −0.116, p = 0.000) subjects. The evidence of publication bias was not found in this meta-analysis. In conclusion, the deficiency of vitamin D is associated with an increased level of BMI in the studies of both diabetic and non-diabetic subjects. Reliable evidence from well-designed future randomized controlled trials is required to confirm the findings from observational studies and to find out the potential regulatory effects of vitamin D supplementation to lower BMI.

CORRELATIONS OF SERUM VITAMIN D WITH METABOLIC PARAMETERS IN ADULT OUTPATIENTS WITH DIFFERENT DEGREES OF OVERWEIGHT / OBESITY COMING FROM AN URBAN COMMUNITY

OBJECTIVE

To describe the correlations between serum 25(OH) vitamin D and anthropometric and metabolic parameters in adult outpatients of both sexes with different BMI coming from an urban community.

SUBJECTS AND METHODS

264 subjects referred for obesity assessment participated - 109 men and 155 women (20-60 years). Body weight and height, waist circumference (WC), blood pressure were recorded. Body composition was assessed by bioelectrical impedance (BIA) on a Tanita BC 420 MA analyzer (Tanita Inc., Japan). Serum 25(OH)D Total, Insulin, High-sensitivity C-reactive protein, blood glucose, total, HDL-cholesterol and triglycerides were measured. The insulin resistance index was calculated (HOMA-IR). Participants with BMI>25.0 kg/m2 underwent standard 75 g OGTT. Statistical analysis was performed on an IBM SPSS Statistics 19.0 for Windows platform (Chicago, IL).

RESULTS

Normal weight was found in 27.2 % of the participants, 24.6 % had overweight, 29.2 % -class I obesity, and 18.9 % - class II or III. Vitamin D was weakly and inversely correlated to different variables in the whole group - such as weight, WC, WC/Height, % body fat and HOMA-IR index (r=-0.231, -0.283, -0.307, -0.339, -0.328 respectively, all p<0.001). Building subgroups based on BMI led to loss of significance. Backward analysis revealed Total-C/LDL-C ratio, and LDL-C/HDL-C ratio as strongest predictors of serum vitamin D (p=0.001; R2=0.204).

CONCLUSION

The association of vitamin D with blood pressure, plasma lipids, glucose and insulin is very weak on an individual level. However, several obesity indices (WC, WC/height ratio, % Body fat from BIA) might be used as a screening tool for subjects at risk for vitamin D deficiency.

Plasma 25-hydroxyvitamin D concentration and risk of type 2 diabetes and pre-diabetes: 12-year cohort study

BACKGROUND

It has been reported that higher plasma 25-hydroxyvitamin D is associated with lower risk of type 2 diabetes. However the results to date have been mixed and no adequate data based on a cohort are available for the high end of the normal range, above approximately 32 ng/ml or 80 nmol/L.

METHODS

We performed a cohort study of 903 adults who were known to be free of diabetes or pre-diabetes during a 1997-1999 visit to a NIH Lipid Research Centers clinic. Plasma 25(OH)D was measured at Visit 8 in 1977-1979. The mean age was 74 years. The visit also included fasting plasma glucose and oral glucose tolerance testing. Follow-up continued through 2009.

RESULTS

There were 47 cases of diabetes and 337 cases of pre-diabetes. Higher 25(OH)D concentrations (> 30 ng/ml) were associated with lower hazard ratios (HR) for diabetes: 30-39 ng/ml or 75-98 nmol/L: HR = 0.31, 95% CI = 0.14-0.70; for 40-49 ng/ml or 100-122 nmol/L: HR = 0.29, CI = 0.12-0.68; for > 50 ng/ml or 125 nmol/L: HR = 0.19, CI = 0.06-0.56. All HRs are compared to < 30 ng/ml or 75 nmol/L. There was an inverse dose-response gradient between 25(OH)D concentration and risk of diabetes with a p for trend of 0.005. Each 10 ng/mL or 25 nmol/L higher 25(OH)D concentration was associated with a HR of 0.64, CI = 0.48-0.86. 25(OH)D concentrations were more weakly inversely associated with pre-diabetes risk, and the trend was not significant.

CONCLUSION

Further research is needed on whether high 25(OH)D might prevent type 2 diabetes or transition of prediabetes to diabetes.

Associations of vitamin D with insulin resistance, obesity, type 2 diabetes, and metabolic syndrome

The aim of this study is to determine the relationships of vitamin D with diabetes, insulin resistance obesity, and metabolic syndrome. Intra cellular vitamin D receptors and the 1-α hydroxylase enzyme are distributed ubiquitously in all tissues suggesting a multitude of functions of vitamin D. It plays an indirect but an important role in carbohydrate and lipid metabolism as reflected by its association with type 2 diabetes (T2D), metabolic syndrome, insulin secretion, insulin resistance, polycystic ovarian syndrome, and obesity. Peer-reviewed papers, related to the topic were extracted using key words, from PubMed, Medline, and other research databases. Correlations of vitamin D with diabetes, insulin resistance and metabolic syndrome were examined for this evidence-based review. In addition to the well-studied musculoskeletal effects, vitamin D decreases the insulin resistance, severity of T2D, prediabetes, metabolic syndrome, inflammation, and autoimmunity. Vitamin D exerts autocrine and paracrine effects such as direct intra-cellular effects via its receptors and the local production of 1,25(OH)₂D₃, especially in muscle and pancreatic β-cells. It also regulates calcium homeostasis and calcium flux through cell membranes, and activation of a cascade of key enzymes and cofactors associated with metabolic pathways. Cross-sectional, observational, and ecological studies reported inverse correlations between vitamin D status with hyperglycemia and glycemic control in patients with T2D, decrease the rate of conversion of prediabetes to diabetes, and obesity. However, no firm conclusions can be drawn from current studies, because (A) studies were underpowered; (B) few were designed for glycemic outcomes, (C) the minimum (or median) serum 25(OH) D levels achieved are not measured or reported; (D) most did not report the use of diabetes medications; (E) some trials used too little (F) others used too large, unphysiological and infrequent doses of vitamin D; and (G) relative paucity of rigorous clinical data on the effects of vitamin D sufficiency on non-calcium endpoints. Although a large number of observational studies support improving T2D, insulin resistance, obesity, and metabolic syndrome with vitamin D adequacy, there is a lack of conclusive evidence from randomized control clinical trials that, these disorders are prevented following optimization of serum levels of 25(OH)D. However, none of the currently conducted clinical studies would resolve these issues. Thus, specifically designed, new clinical studies are needed to be conducted in well-defined populations, following normalizing the serum vitamin D levels in vitamin D deficient prediabetes subjects, to test the hypothesis that hypovitaminosis D worsens these disorders and correction would alleviate it.

Correlation of cardio-metabolic parameters with vitamin D status in healthy premenopausal women

PURPOSE

Vitamin D has been associated with metabolic disorders and increasing risk of cardiovascular diseases, with conflicting results. Aim of our study was to evaluate the relationship, if any, between cardio-metabolic risk factors and serum 25(OH)D concentrations in healthy women in premenopausal age.

METHODS

We enrolled 200 healthy women, aged 19-50 years (mean age ± SD, 38 ± 11 years). In each subject, we measured serum 25(OH)D in relation to metabolic biomarkers and cardiovascular parameters.

RESULTS

A status of vitamin D deficiency was found in 48% of the study population, while 38% showed levels higher than 30 ng/ml. Fasting glucose and insulin levels were significantly higher in subjects with vitamin D deficiency/insufficiency (P = 0.034 and P = 0.049, respectively) as well as HOMA-IR (P = 0.05). HDL cholesterol was significantly lower (P = 0.024) and intima-media thickness (IMT) higher (P = 0.014) in the vitamin D deficient/insufficient subjects. Moreover, serum 25(OH)D levels inversely correlated with insulin levels (P = 0.0001) and intima-media thickness (P = 0.015), and directly with serum HDL cholesterol (P = 0.010). At univariate regression analysis, the parameters that were significantly associated with vitamin D levels were insulin (P = 0.050), HDL cholesterol (P = 0.016), and intima-media thickness (P = 0.015). At multivariate analysis adjusted for age and BMI, vitamin D was still significantly associated with HDL cholesterol and intima-media thickness.

CONCLUSIONS

A positive association between vitamin D and HDL cholesterol was found in healthy women without any evidence of metabolic disorders, with a significant inverse correlation between vitamin D and IMT. These results suggest a possible protective role of 25(OH)D in cardiovascular disorders.

Serum Lipid, Vitamin D Levels, and Obesity in Perimenopausal and Postmenopausal Women in Non-Manual Employment

BACKGROUND Increasing age, increased body mass index (BMI), and abnormal lipid profiles contribute to an increased risk of vitamin D deficiency. Women who have a perimenopausal and postmenopausal reduction in estrogen levels are a high-risk group for vitamin D deficiency. The aims of this study were to compare the serum vitamin D levels, lipid profile, and BMI between perimenopausal and postmenopausal women in non-manual employment, and to determine whether there were any interdependent factors. MATERIAL AND METHODS Three hundred women in non-manual employment, aged between 44-66 years, were divided into three groups: early perimenopausal; late perimenopausal; and postmenopausal. Laboratory tests included measurement of serum lipid profiles and vitamin D levels, the BMI, waist-hip ratio (WHR) and body fat were measured. Statistical analysis included F-test analysis of variance and the least significance difference (LSD) test was used for multiple comparisons. RESULTS For the 300 women who were in non-manual employment, and in the early and late perimenopausal and postmenopausal periods, serum vitamin D levels were reduced (mean 16.8±8.7 ng/mL); 29% of women had abdominal obesity; 41% had excessive body fat accumulation; and 56% had an increased body mass index (BMI) (>25 kg/m²) with raised total cholesterol, low-density lipoprotein (LDL) cholesterol, LDL/high-density lipoprotein (HDL), and total cholesterol/HDL ratios (p<0.05). CONCLUSIONS The findings of this study showed that in perimenopausal and postmenopausal women in non-manual employment, serum vitamin D levels were associated with serum lipid profile and degrees of obesity.

Vitamin D deficiency is associated with metabolic syndrome in postmenopausal women

OBJECTIVE

To evaluate the association between vitamin D (VD) deficiency and risk factors for metabolic syndrome (MetS) in postmenopausal women.

STUDY DESIGN

Observational, cross-sectional cohort study.

MAIN OUTCOME MEASURES

In this study, 463 women, aged 45-75 years, with amenorrhea >12months, without VD supplementation or established cardiovascular disease were included. Clinical and anthropometric data were collected. Biochemical parameters, including total cholesterol (TC), HDL, LDL, triglycerides, glucose, insulin and 25-hydroxyvitamin-D [25(OH)D] were measured. Women meeting three or more of the following criteria were diagnosed with MetS: waist circumference >88cm, triglycerides ≥150mg/dL, HDL <50mg/dL, blood pressure ≥130/85mmHg and glucose ≥100mg/dL. Serum 25(OH)D levels were classified as sufficient (≥30ng/mL), insufficient (20-29ng/mL) or deficient (<20ng/mL). ANOVA, chi-square test and logistic regression (odds ratio, OR) were used for statistical analysis.

RESULTS

Serum 25(OH)D levels were sufficient in 148 women (32.0%), insufficient in 151 (32.6%) and deficient in 164 (35.4%). Women with low 25(OH)D levels had higher TC, triglycerides, insulin and HOMA-IR levels (p<0.05). MetS was detected in 57.8% (182/315) of women with hypovitaminosis D (insufficient and deficient) and in 39.8% (59/148) of those with sufficient VD​​ (p=0.003). In a multivariate logistic regression analysis, a low 25(OH)D level (<30ng/mL) was significantly associated with MetS (OR1.90, 95%CI=1.26-2.85), high triglyceride levels (OR1.55, 95%CI=1.13-2.35), and low HDL levels (OR1.60, 95%CI=1.19-2.40) (p<0.05) compared with women with sufficient 25(OH)D levels, after adjusting for age, time since menopause, body mass index, smoking and physical exercise. The mean concentration of 25(OH)D decreased with increasing numbers of MetS components (p=0.016).

CONCLUSIONS

VD deficiency in postmenopausal women was associated with a higher prevalence of MetS. Women with VD deficiency had a higher risk of MetS, hypertriglyceridemia and low HDL than those with adequate levels.

Effect of high-dose vitamin D supplementation on cardiometabolic risk factors in subjects with metabolic syndrome: a randomized controlled double-blind clinical trial

PURPOSE

The evidence in support of the effect of vitamin D deficiency on cardiovascular diseases is inconsistent. The objective of this randomized, controlled, double-blind study was to assess the effect of high-dose vitamin D supplementation on cardiometabolic risk factors in subjects with metabolic syndrome.

METHODS

Eighty subjects were randomized to receive 50,000 IU vitamin D or matching placebo weekly for 16 weeks. Fasting blood sugar, homeostasis model assessment of insulin resistance, insulin sensitivity (Quicki), serum lipid profiles (low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride (TG) and total cholesterol), anthropometric factors and blood pressure were assessed before and after intervention. Dietary intake and sun exposure were also determined. The trial was registered at http://www.irct.ir (code: IRCT201409033140N14).

RESULTS

Participants were 40.49 ± 5.04 years and 49 % male. All of the intervention group and 97 % of placebo group were vitamin D deficient or insufficient (25-hydroxyvitamin D <75 nmol/L). After intervention, serum 25(OH)D concentration was increased by 61.93 nmol/L in intervention group, while it was decreased in placebo group (p < 0.001). There was a significant change in TG concentration after 4 months (p < 0.001). Other metabolic or anthropometric factors did not change significantly (p = 0.05).

CONCLUSION

Supplementation with high-dose vitamin D for 4 months improved vitamin D status and decreased TG levels in subjects with metabolic syndrome. However, it did not have any beneficial effects on other cardiometabolic risk factors; this might be due to the inadequate vitamin D status attained in this study which was conducted in a severely deficient region.

Association between serum 25-hydroxyvitamin D concentrations and prevalence of metabolic syndrome

PURPOSE

There is now good evidence that 25-hydroxyvitamin D (25OHD) status may have an important impact on the development and progression of cardiovascular disease. Because of the potential involvement of vitamin D deficiency in blood pressure control and immune responses, we aimed to investigate whether there was a relationship between 25OHD status and the prevalence of metabolic syndrome in an Iranian population.

MATERIAL/METHODS

The study was carried out on a sample of 846 subjects [357(42.19%) males and 489(57.80%) females], derived from MASHAD STUDY. Serum 25OHD levels were measured using a competitive electroluminescence protein binding assay. Anthropometric indices were measured using standard protocols.

RESULTS

Serum 25OHD was 12.7 (6.8-18.4) ng/ml in the metabolic syndrome (MetS) group and 14.1 (8.8-19.0) ng/ml in the group without metabolic syndrome (P=0.43). The frequency of vitamin D deficiency was 80.7% and 79.0% in subjects with or without metabolic syndrome in Iranian population.

CONCLUSIONS

We found no significant difference in serum 25OHD concentrations between individuals with or without MetS and no significant linear relationship between serum 25OHD and several CVD risk factors.

Genetic influence on circulating vitamin D among Saudi Arabians

OBJECTIVES

 To examine the effect of most common studied single nucleotide polymorphisms (SNP) on serum 25-hydroxyvitamin D (25OHD) levels in Saudi Arabian population. 

METHOD

A cross-sectional observational study was carried out between July 2014 and October 2015, at King Fahd Hospital of the University (KFHU), Al-Khobar, Kingdom of Saudi Arabia. After informed consent, blood samples from 283 subjects living in the Eastern province were collected for 25-OHD measurement and genetic analysis of SNPs in vitamin D receptor (VDR) [rs2228570 and rs1544410], Cytochrome, P450 family 2 (CYP2R1) [rs10741657 and rs1993116], and Group-specific components (GC) [rs2282679 and rs4588]. 

RESULTS

Vitamin D deficiency was found in 87.6% and insufficiency in 7.7%. The percentages of the different alleles of the 6 SNPs tested ranged between 0-62.5%. There was significant difference between the AA, AG, and GG alleles of VDR rs2228570. The carries of GG allele was associated with increased risks of vitamin D insufficiency (p less than 0.002) and deficiency (p less than or equal to 0.005). The CYP2R1 rs10741657 gene showed that AG and GG allele carriers had significant risk of vitamin D deficiency. AG allele (normal versus Insufficiency p less than 0.02 and normal versus deficiency p less than 0.08) and GG allele normal versus deficiency (p less than 0.002) and insufficiency versus deficiency (p less than 0.001). For group-specific components (GC rs4588), there was only significant difference between the normal and deficiency for the AC allele (p less than 0.0001).

CONCLUSION

The presence of GG allele of the SNP rs2228570 of VDR gene, SNPs rs4588 of GC gene and CYP2R1 rs10741657 gene was associated with vitamin D deficiency.

The association between gender difference with metabolic syndrome, metabolic syndrome score and serum vitamin D levels in Korean adults

This study assessed the association between gender difference with metabolic syndrome (MetS), metabolic syndrome score (MSS) and serum vitamin D levels in Korean adults. Analyses were restricted to 5147 adults (2162 men; 2985 women) aged 20 and older, using the 2012 Korean National Health and Nutrition Examination Survey (KNHANES) data. In the non-adjusted model, serum 25-hydroxyvitamin D [25(OH)D] levels were inversely associated with MetS (p = .001) and MSS (p = .009) in men, but positively associated with MetS (p = .002) and MSS (p < .001) in women. However, when adjusted for related variables (including age), serum 25(OH)D levels were inversely associated with MetS (p < .001) and MSS (p < .001) in men, but were not associated with MetS (p = .200) and MSS (p = .541) in women. In conclusion, increases in MetS and its components were inversely associated with the serum vitamin D concentration in men.

A vitamin D pathway gene-gene interaction affects low-density lipoprotein cholesterol levels

Much evidence suggests an association between vitamin D deficiency and chronic diseases such as obesity and dyslipidemia. Although genetic factors play an important role in the etiology of these diseases, only a few studies have investigated the relationship between vitamin D-related genes and anthropometric and lipid profiles. The aim of this study was to investigate the association of three vitamin D-related genes with anthropometric and lipid parameters in 542 adult individuals. We analyzed the rs2228570 polymorphism in the vitamin D receptor gene (VDR), rs2134095 in the retinoid X receptor gamma gene (RXRG) and rs7041 in the vitamin D-binding protein gene (GC). Polymorphisms were genotyped by TaqMan allelic discrimination. Gene-gene interactions were evaluated by the general linear model. The functionality of the polymorphisms was investigated using the following predictors and databases: SIFT (Sorting Intolerant from Tolerant), PolyPhen-2 (Polymorphism Phenotyping v2) and Human Splicing Finder 3. We identified a significant effect of the interaction between RXRG (rs2134095) and GC (rs7041) on low-density lipoprotein cholesterol (LDL-c) levels (P=.005). Furthermore, our in silico analysis suggested a functional role for both variants in the regulation of the gene products. Our results suggest that the vitamin D-related genes RXRG and GC affect LDL-c levels. These findings are in agreement with other studies that consistently associate vitamin D and lipid profile. Together, our results corroborate the idea that analyzing gene-gene interaction would be helpful to clarify the genetic component of lipid profile.

Serum 25-hydroxyvitamin D and metabolic syndrome in a Japanese working population: The Furukawa Nutrition and Health Study

OBJECTIVE

Increasing evidence has suggested a protective role of vitamin D on metabolic syndrome (MetS). However, studies addressing this issue are limited in Asia and it remains unclear whether calcium could modify the association. We examined the association of serum 25-hydroxyvitamin D (25(OH)D) status with MetS, and the potential effect modification by calcium intake in a Japanese working population.

METHODS

Study subjects were 1790 workers, ages 18 to 69 y, who participated in a health survey at the time of periodic checkup. MetS was defined according to the joint interim statement. Serum 25(OH)D was measured by a protein binding assay. Multilevel logistic regression was used to estimate the odds ratio (OR) with adjustment for potential confounding variables.

RESULTS

An inverse trend was observed between 25(OH)D and MetS. Compared with those with a 25(OH)D of <20 ng/mL, multivariable adjusted OR (95% confidence interval) for MetS was 0.79 (0.55-1.15) and 0.52 (0.25-1.04) for those with a 25(OH)D of 20 to 29 ng/mL and ≥30 ng/mL, respectively (P for trend = 0.051). Similar association was observed in the analysis using quartile categories of 25(OH)D; the OR in the highest quartile of 25(OH)D compared with the lowest quartile was 0.61 (0.36-1.01) (P for trend = 0.046). This association was noted only in older subjects (≥44 y). The inverse association between serum 25(OH)D and MetS was more pronounced in subjects with high calcium intake. The inverse association between 25(OH)D and MetS appears to be linear according to restricted cubic spline regression. There was inverse, but statistically nonsignificant, associations between 25(OH)D and each component of MetS.

CONCLUSION

Our results suggest that higher circulating vitamin D is associated with decreased likelihood of having MetS among Japanese adults.