25-hydroxyvitamin D is associated with adiposity and cardiometabolic risk factors in a predominantly vitamin D-deficient and overweight/obese but otherwise healthy cohort

Vitamin D Inadequacy and Its Relation to Body Fat and Muscle Mass in Adult Women of Childbearing Age

To assess the correlation between vitamin D status and body composition variables in adult women of childbearing age, a cross-sectional study was conducted involving women aged 20-49 years. The participants were categorized based on their vitamin D status and further divided according to body mass index (BMI). Anthropometric and biochemical data were collected to compute body composition indices, specifically body fat and muscle mass. The sample included 124 women, with 63.70% exhibiting vitamin D inadequacy. Women with inadequate vitamin D status demonstrated a higher waist-to-height ratio (WHtR) and body adiposity index (BAI), along with a lower BMI-adjusted muscle mass index (SMI BMI), compared to those with adequate levels of vitamin D (p = 0.021; p = 0.019; and p = 0.039, respectively). A positive correlation was observed between circulating concentrations of 25(OH)D and SMI BMI, while a negative correlation existed between circulating concentrations of 25(OH)D and waist circumference (WC), WHtR, conicity index (CI), fat mass index (FMI), body fat percentage (% BF), and fat-to-muscle ratio (FMR). These findings suggest that inadequate vitamin D status may impact muscle tissue and contribute to higher body adiposity, including visceral adiposity. It is recommended that these variables be incorporated into clinical practice, with a particular emphasis on WHtR and SMI BMI, to mitigate potential metabolic consequences associated with vitamin D inadequacy.

Physiological Evidence and Therapeutic Outcomes of Vitamin D on Cardiovascular Diseases

Vitamin D hormone is an important regulator of various physiological functions, and its deficiency is characterized by an imbalance in parathyroid hormone and calcium homeostasis. The role of vitamin D in cardiovascular physiology is well demonstrated in animal and humanbased studies. In this context, hyperlipidemia, increased atherogenic plaques, cardiac inflammation, hypertension, myocarditis, myocardial infarction, and heart failure are some of the commonest known conditions connected with vitamin D deficiency. Supplementation of vitamin D is recommended to achieve normal serum vitamin D concentrations, nonetheless, in clinical trials often seen discrepancies concerning the supplementation effects and effectiveness. This review summarizes the data on the role of vitamin D in cardiovascular health along with some recent clinical findings regarding the effects of vitamin D supplementation.

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.

Obesity and dysregulated innate immune responses: impact of micronutrient deficiencies

Obesity is associated with the development of various complications, including diabetes, atherosclerosis, and an increased risk for infections, driven by dysfunctional innate immune responses. Recent insights have revealed that the availability of nutrients is a key determinant of innate immune cell function. Although the presence of obesity is associated with overnutrition of macronutrients, several micronutrient deficiencies, including Vitamin D and zinc, are often present. Micronutrients have been attributed important immunomodulatory roles. In this review, we summarize current knowledge of the immunomodulatory effects of Vitamin D and zinc. We also suggest future lines of research to further improve our understanding of these micronutrients; this may serve as a stepping-stone to explore micronutrient supplementation to improve innate immune cell function during obesity.

Circulating 25-hydroxyvitamin D is associated with metabolic phenotypes of obesity: National Food and Nutrition Surveillance

Different phenotypes of obesity are each related with different complications and comorbidities. We hypothesized that suboptimal vitamin D status is directly associated with an unhealthy metabolic status, especially if allied with obesity. This cross-sectional study was performed in the framework of the National Food and Nutrition Surveillance. Overall, 1098 men and women participated in this study. In addition to height and weight, serum concentrations of 25-hydroxyvitamin D (25(OH)D) and glycemic and lipidemic status were evaluated. Then participants were classified into 4 groups based on body mass index and lipidemic and glycemic profile status, as follows: hyperglycemic-dyslipidemic obese (HDO), hyperglycemic-dyslipidemic nonobese (HDNO), normoglycemic-normolipidemic obese (NNO), and normoglycemic-normolipidemic nonobese (NNNO). In this study, 31.6% of participants were classified as HDO, 7.5% as HDNO, 34.5% as NNO, and 26.4% as NNNO. The frequency of suboptimal vitamin D status was more prevalent in HDO (81.8%) than in other phenotypes (HDNO, 80%; NNO, 77.6%; NNNO, 73.8%; P = .015). In the multivariate model, suboptimal vitamin D status significantly increased the odds of being NNO (odds ratio [OR], 1.28; 95% CI, 0.84-1.95), HDNO (OR, 1.48; 95% CI, 0.77-2.83), and HDO (OR, 1.73; 95% CI, 1.11-2.7) compared with the NNNO group. Likewise, in multivariate model, per each unit (ng/mL) increment in 25(OH)D concentration, the odds of HDNO and HDO decreased significantly by 4% (OR, 0.96; 95% CI, 0.94-0.98) and 7% (OR, 0.93; 95% CI, 0.92-0.95), respectively. The results of the study showed a significant relationship between serum 25(OH)D concentrations and metabolic obesity phenotypes; these data confirm the association between suboptimal vitamin D status and metabolic complications, especially in obese individuals.

Association of Body Weight With Response to Vitamin D Supplementation and Metabolism

IMPORTANCE

In the Vitamin D and Omega-3 Trial (VITAL), the effects of randomized vitamin D supplementation (cholecalciferol), 2000 IU/d, reduced the risk of several health outcomes among participants with normal, but not elevated, body weights. It was unclear whether weight had any association with the outcomes of the supplementation.

OBJECTIVE

To investigate whether baseline body mass index (BMI) modifies vitamin D metabolism and response to supplementation.

DESIGN, SETTING, AND PARTICIPANTS

VITAL is a completed randomized, double-blind, placebo-controlled trial for the primary prevention of cancer and cardiovascular disease. In the present cohort study, an analysis was conducted in a subset of VITAL participants who provided a blood sample at baseline and a subset with a repeated sample at 2 years' follow-up. VITAL was conducted from July 1, 2010, to November 10, 2018; data analysis for the present study was conducted from August 1, 2021, to November 9, 2021.

INTERVENTIONS

Treatment outcomes of vitamin D, 2000 IU/d, supplementation vs placebo associated with clinical and novel vitamin D-related biomarkers by BMI category adjusted for other factors associated with vitamin D status.

MAIN OUTCOMES AND MEASURES

Multivariable-adjusted means (SE) or 95% CIs of vitamin D-related serum biomarkers at baseline and follow-up: total 25-hydroxyvitamin D (25-OHD), 25-OHD3, free vitamin D (FVD), bioavailable vitamin D (BioD), vitamin D-binding protein (VDBP), albumin, parathyroid hormone (PTH), and calcium, and log-transformed as needed.

RESULTS

A total of 16 515 participants (mean [SD] age, 67.7 [7.0] years; 8371 women [50.7%]; 12420 non-Hispanic White [76.9%]) were analyzed at baseline, including 2742 with a follow-up blood sample. Before randomization, serum total 25-OHD levels were incrementally lower at higher BMI categories (adjusted mean [SE]: underweight, 32.3 [0.7] ng/mL; normal weight, 32.3 [0.1] ng/mL; overweight, 30.5 [0.1] ng/mL; obesity class I, 29.0 [0.2] ng/mL; and obesity class II, 28.0 [0.2] ng/mL; P < .001 for linear trend). Similarly, baseline 25-OHD3, FVD, BioD, VDBP, albumin, and calcium levels were lower with higher BMI, while PTH level was higher (all P < .001 for linear trend). Compared with placebo, randomization to vitamin D supplementation was associated with an increase in total 25-OHD, 25-OHD3, FVD, and BioD levels compared with placebo at 2 years' follow-up, but increases were significantly lower at higher BMI categories (all treatment effect interactions P < .001). Supplementation did not substantially change VDBP, albumin, PTH, or calcium levels.

CONCLUSIONS AND RELEVANCE

In this randomized cohort study, vitamin D supplementation increased serum vitamin D-related biomarkers, with a blunted response observed for participants with overweight or obesity at baseline. These longitudinal findings suggest that BMI may be associated with modified response to vitamin D supplementation and may in part explain the observed diminished outcomes of supplementation for various health outcomes among individuals with higher BMI.

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.

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.

The role of sleep in PCOS: what we know and what to consider in the future

INTRODUCTION

Sleep disturbance and clinical sleep conditions disrupt endocrine signals, energy expenditure and nutritional intake. Women with polycystic ovary syndrome (PCOS) are at higher risk of sleep disturbances and clinical conditions. It is possible that sleep may contribute to the exacerbation of PCOS. This review aims to explore the relationship between sleep and chronic disease, particularly in women with PCOS.

AREAS COVERED

This review narratively explores what sleep is, how to measure sleep and the possible mechanisms that support the link between sleep in adipose tissue deposition, insulin resistance and the presentation of PCOS.

EXPERT OPINION

Research shows that disturbed sleep and clinical sleep conditions disrupt energy expenditure. This may increase adipose tissue deposition and exacerbate insulin resistance which are known to worsen the presentation of PCOS. Further, sleep disturbance in women with PCOS may ameliorate any positive lifestyle changes made after diagnosis. Cognitive behavioural therapy interventions for sleep are a successful strategy for the management of sleep disturbances in the general population. However, such interventions are yet to be trialled in women with PCOS. Given the proposed implications, interventions to improve sleep could provide additional support for women with PCOS to successfully implement lifestyle strategies and should be further investigated.

Vitamin D is associated with body composition and fat intake, but not with cardiometabolic parameters in adults with obesity

Adults with obesity are at higher risk for developing hypovitaminosis D. Some studies suggest that reduced levels of serum 25-hydroxyvitamin D (25(OH)D) may also be related to disorders in cardiometabolic parameters. However, because of the association between 25(OH)D and obesity, we hypothesized that body composition can be a confounding factor in the association of 25(OH)D with cardiometabolic parameters, and that 25(OH)D is inversely associated with body composition and cardiometabolic parameters and directly associated with fat intake. The aim of this study was to analyze the associations between 25(OH)D with body composition, fat intake, and cardiometabolic parameters in adults with obesity. This cross-sectional study consisted of 52 adults with obesity (61.53% female; 37.50 ± 6.88 years; body mass index [BMI]: 33.60 ± 2.89 kg/m²). Cardiometabolic parameters (fasting blood glucose, insulin resistance index, C-reactive protein, blood pressure, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and cholesterol), body mass, BMI, waist circumference, body fat percentage, and fat intake were evaluated. Body mass was negatively associated with 25(OH)D (β = -0.108; P = .048; and R² = 0.090) and BMI (β = -0.621; P = .031; and R² = 0.103), both adjusted for fat intake. 25(OH)D was positively associated with fat intake (β = 0.129; P = .045 and R² = 0.078) adjusted for sex, age, and skin color. Cardiometabolic parameters were not associated with 25(OH)D, even after adjusted by body composition variables. However, the high prevalence of hypovitaminosis D (75%) and the negative association between 25(OH)D and body composition reinforce the importance of analyzing and monitoring vitamin D status in this population.

Secondary Hyperparathyroidism Before and After Bariatric Surgery: a Prospective Study with 2-Year Follow-Up

PURPOSE

Secondary hyperparathyroidism (SHPT) is linked to obesity. Bariatric surgery may be associated with calcium and vitamin D deficiencies leading to SHPT. This study aimed to detect the prevalence of SHPT before and after bariatric surgery.

METHODS

This prospective study assessed the prevalence of SHPT after sleeve gastrectomy (SG, n = 38) compared to one-anastomosis gastric bypass (OAGB, n = 86). All patients were followed up for 2 years. Bone mineral density (BMD) was assessed using dual-energy X-ray absorptiometry.

RESULTS

Of the 124 patients, 71 (57.3%) were females, and 53 (42.7%) were males, with a mean age of 37.5 ± 8.8 years. Before surgery, 23 patients (18.5%) suffered from SHPT, and 40 (32.3%) had vitamin D deficiency. The prevalence of SHPT increased to 29.8% after 1 year and 36.3% after 2 years. SHPT was associated with lower levels of vitamin D and calcium and higher reduction of BMD in the hip but not in the spine. After 2 years, SHPT was associated with a significantly lower T-score in the hip. SHPT and vitamin D deficiency were significantly more common in patients subjected to OAGB compared to SG (p = 0.003, and p < 0.001, respectively). There is a strong negative correlation between vitamin D levels and parathormone levels before and after surgery.

CONCLUSION

Prevalence of SHPT is high in obese patients seeking bariatric surgery, especially with lower vitamin D levels. Bariatric surgery increases the prevalence of SHPT up to 2 years. Gastric bypass is associated with a higher risk of developing SHPT compared to SG.

Vitamin D Deficiency Is Associated with Glycometabolic Changes in Nondiabetic Patients with Arterial Hypertension

Recent evidence indicates that mildly increased fasting and post-oral load blood glucose concentrations contribute to development of organ damage in nondiabetic patients with hypertension. In previous studies, vitamin D deficiency was associated with decreased glucose tolerance. The aim of this study was to examine the relationships between serum 25(OH)D levels and glucose tolerance and insulin sensitivity in hypertension. In 187 nondiabetic essential hypertensive patients free of cardiovascular or renal complications, we measured serum 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) and performed a standard oral glucose tolerance test (OGTT). Patients with 25(OH)D deficiency/insufficiency were older and had significantly higher blood pressure, fasting and post-OGTT (G-AUC) glucose levels, post-OGTT insulin (I-AUC), PTH levels, and prevalence of metabolic syndrome than patients with normal serum 25(OH)D. 25(OH)D levels were inversely correlated with age, blood pressure, fasting glucose, G-AUC, triglycerides, and serum calcium and PTH, while no significant relationships were found with body mass index (BMI), fasting insulin, I-AUC, HOMA index, and renal function. In a multivariate regression model, greater G-AUC was associated with lower 25(OH)D levels independently of BMI and seasonal vitamin D variations. Thus, in nondiabetic hypertensive patients, 25(OH)D deficiency/insufficiency could contribute to impaired glucose tolerance without directly affecting insulin sensitivity.

Perinatal factors and high-sensitive C-reactive protein levels during adolescence

Objective

To examine whether perinatal factors are associated with low-grade inflammation measured by high-sensitivity C-reactive protein levels during adolescence.

Methods

Nested case-control study of 125 teenagers who were born by Cesarean delivery and had high-sensitivity C-reactive protein levels determined at 15–17 years. Data on obstetric and perinatal factors were recorded prospectively at the time of their birth.

Results

Median values of high-sensitivity C-reactive protein were significantly higher in teenagers, who were born as large for gestational age or with maternal diabetes compared to others (2.54 vs 0.34 mg/L; p < 0.024), and born during spring or summer compared to those born during winter or autumn (0.48 vs 0.27 mg/L; p < 0.023). No other perinatal associations were detected (for ex. such as electivity of operation, onset of labor, rupture of fetal membranes, cervical dilatation at delivery, gestational age, Apgar scores at 5 min, umbilical blood pH value, administration of neonatal antibiotics or need of neonatal intensive care treatment) in CRP levels. Further, teenagers with current body mass index in the highest tertile, regular medication for chronic disease and girls using oral contraceptives had significantly higher high-sensitivity C-reactive protein levels than others.

Conclusion

Prenatal exposures such as maternal metabolic environment and seasonality may have longterm effects on the low-grade inflammation and later cardiometabolic risks. Seasonality might be partly explained by maternal vitamin D levels during pregnancy, and thus future efforts are warranted to ensure sufficient vitamin D availability during pregnancy. Surprisingly, no other significant associations were detected between perinatal characteristics and high-sensitivity C-reactive protein levels.

Nutritional Supplements and Complementary Therapies in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) affects 1 in 5 women of reproductive age, and is characterized by menstrual irregularities, clinical or biochemical hyperandrogenism, and the presence of polycystic ovary morphology. One of the recommended treatment strategies in the international evidence-based guidelines is lifestyle modification, which includes diet and exercise, with the aim of improving a range of health outcomes. The incurable nature of PCOS reinforces the importance of developing novel and innovative symptomatic relief strategies, which are currently the only available approaches for improving quality of life for these women. Women with PCOS tend to be nutrient deficient in many common vitamins and minerals, thought to be associated with the psychological (depression, anxiety, etc.) and physiological (insulin resistance, diabetes, infertility, etc.) sequelae of the condition. Nutrient supplementation and the integration of complementary medicine as adjuncts to traditional lifestyle-based therapies in PCOS could therefore provide additional benefits to these women. In this review, we synthesize the evidence regarding nutrient supplementation and complementary therapies in PCOS, predominantly from randomized controlled trials, systematic reviews, and meta-analyses, to provide an overview of the state of knowledge in this field. The evidence to date suggests that specific vitamins (B-12, inositols, folate, vitamins D, E, and K), vitamin-like nutrients (bioflavonoids and α-lipoic acid), minerals (calcium, zinc, selenium, and chromium picolinate), and other formulations (melatonin, ω-3 fatty acids, probiotics, and cinnamon), as well as some complementary approaches such as acupuncture and yoga may be beneficial in PCOS. However, there remain areas of uncertainty and key limitations in the literature that must be overcome before these therapies can be integrated into routine clinical practice.

Multiple nutritional deficiencies among adolescents undergoing bariatric surgery: who is at risk?

BACKGROUND

Nutritional deficiencies among adolescents undergoing bariatric surgery (BS) have not been evaluated a in relation to patient's sex.

OBJECTIVES

We compared the preoperative nutritional profile of adolescents characterized by sex and single versus multiple deficiencies.

SETTING

University hospital.

METHODS

Cross-sectional retrospective chart review of 415 eligible adolescents who underwent primary BS between 2011 and 2020. Data included preoperative demographic, anthropometric information as well as three sets of nutritional variables: anemia-related, calcium-related, and other nutritional variables.

RESULTS

The sample comprised 247 males (59.5%) with a mean age of 15.89 ± 1.03 years and a mean body mass index (BMI) of 47.80 ± 6.57 kg/m². Most common deficiencies were vitamin D (92.3%), albumin (51.8%), anemia (15.9%), zinc (11.1%), and vitamin B₁₂ (8%); 21.7% had hyperparathyroidism. Females exhibited a significantly higher prevalence of low hemoglobin, low hematocrit, and iron deficiency. Multiple deficiencies were present among 97.6%, 73.2%, 23.6%, 15%, and 12.6% of adolescents, who had vitamin D, albumin, hemoglobin, zinc, and vitamin B₁₂ deficiencies, respectively. Univariate analysis revealed that adolescents with a BMI of ≥50 kg/m² were 1.24 times more likely to have multiple deficiencies (P = .004). Using multivariate log-binomial regression, BMI of ≥50 kg/m² was a significant predictor of multiple nutritional deficiencies (P = .005, adjusted risk ratio = 1.23, 95% CI 1.06-1.42). Age and sex were not independent predictors of multiple nutritional deficiencies.

CONCLUSION

To our knowledge, this study is the first to appraise single and multiple nutritional deficiencies in adolescents undergoing BS by sex. Multiple deficiencies were common. Females are at higher risk of anemia-related deficiencies. A BMI of ≥50 kg/m² independently and significantly predicted multiple nutritional deficiencies. Correction before and monitoring after surgery are important.

Relationship of Vitamin D Deficiency and Fatty Liver in Children as Defined by Multiple Imaging and Histologic Endpoints

Objectives

The relationship between vitamin D deficiency (VDD) and pediatric nonalcoholic fatty liver disease (NAFLD) remains uncertain due to conflicting results and few studies with histologic endpoints. We therefore used multiple imaging and histologic NAFLD endpoints to more comprehensively assess the association between VDD and NAFLD in a large pediatric population.

Methods

Data were obtained from an ongoing pediatric NAFLD study in Bronx, NY. Briefly, overweight and obese children aged 2-18 years with alanine aminotransferase (ALT) levels ≥ 35 U/L were serially enrolled. Liver biopsy was obtained in accordance with clinical guidelines. All participants had liver imaging, namely, controlled attenuation parameter (CAP; Echosens, France) to assess steatosis and, to assess fibrosis, vibration controlled transient elastography (VCTE; FibroScan™, Echosens, France) and acoustic radiation force impulse (ARFI; Philips, Netherlands) imaging. Levels of 25-hydroxyvitamin D were measured serologically.

Results

N=276 (88%) of 315 participants had 25-OH vitamin D results, of whom 241 (87%) were Hispanic, 199 (72%) were male, and 92 (33%) underwent liver biopsy. VDD was univariately associated with high waist circumference (p=0.004), high-density lipoprotein level (p=0.01), season (p=0.009), and CAP score (p=0.01). In multivariate analysis, only waist circumference (p=0.0002) and biopsy inflammation grade (p=0.03) were associated with VDD, though the latter had not approximated statistical significance in univariate analysis (p=0.56). There was no association between VDD and hepatic steatosis, ballooning, NAFLD Activity Score, ARFI or VCTE elasticity scores.

Conclusions

VDD was not associated with NAFLD defined by imaging and histologic endpoints, except for a possible relation with histologic inflammation grade.

Mechanisms Involved in the Relationship between Vitamin D and Insulin Resistance: Impact on Clinical Practice

Recent evidence has revealed anti-inflammatory properties of vitamin D as well as extra-skeletal activity. In this context, vitamin D seems to be involved in infections, autoimmune diseases, cardiometabolic diseases, and cancer development. In recent years, the relationship between vitamin D and insulin resistance has been a topic of growing interest. Low 25-hydroxyvitamin D (25(OH)D) levels appear to be associated with most of the insulin resistance disorders described to date. In fact, vitamin D deficiency may be one of the factors accelerating the development of insulin resistance. Vitamin D deficiency is a common problem in the population and may be associated with the pathogenesis of diseases related to insulin resistance, such as obesity, diabetes, metabolic syndrome (MS) and polycystic ovary syndrome (PCOS). An important question is the identification of 25(OH)D levels capable of generating an effect on insulin resistance, glucose metabolism and to decrease the risk of developing insulin resistance related disorders. The benefits of 25(OH)D supplementation/repletion on bone health are well known, and although there is a biological plausibility linking the status of vitamin D and insulin resistance supported by basic and clinical research findings, well-designed randomized clinical trials as well as basic research are necessary to know the molecular pathways involved in this association.

Vitamin D and COVID-19: An Overview of Recent Evidence

The novel coronavirus severe acute respiratory syndrome (SARS-CoV-2) has progressed rapidly from an outbreak to a global pandemic, with new variants rapidly emerging. Coronavirus disease 2019 (COVID-19), the disease resulting from SARS-CoV-2 infection, can lead to multiorgan damage. Due to the extremely contagious and fatal nature of the virus, it has been a priority of medical research to find effective means of treatment. Amid this search, the role of vitamin D in modulating various aspects of the innate and adaptive immune system has been discussed. This review aims to consolidate the research surrounding the role of vitamin D in the treatment and prevention of COVID-19. While there are some conflicting results reported, the consensus is that vitamin D has a host of immunomodulatory effects which may be beneficial in the context of COVID-19 and that low levels of vitamin D can result in dysfunction of crucial antimicrobial effects, potentially contributing to poor prognosis. Studies also show that the effects of low vitamin D can be mitigated via supplementation, although the benefits of vitamin D supplementation in the treatment of COVID-19 remain controversial.

Relationship between 25 Hydroxyvitamin D, Overweight/Obesity Status, Pro-Inflammatory and Oxidative Stress Markers in Patients with Type 2 Diabetes: A Simplified Empirical Path Model

Vitamin D deficiency is highly prevalent in patients with overweight/obesity and type 2 diabetes (T2DM). Herein, we investigated the relationship between vitamin D status and overweight/obesity status, insulin resistance (IR), systemic inflammation as well as oxidative stress (OS). Anthropometric and laboratory assessments of 25-hydroxyvitamin D (25(OH)D) and glycemic, pro-inflammatory and OS biomarkers were performed in a sample of 47 patients with T2DM who were divided into categories based on overweight and degree of obesity. The main findings were: the overweight/obesity status correlated negatively with the degree of serum 25(OH)D deficiency (ρ = −0.27) with a trend towards statistical significance (p = 0.069); the homeostasis model assessment of insulin resistance (HOMA-IR) was significantly different (p = 0.024) in patients with 25(OH)D deficiency, as was total oxidant status (TOS) and oxidative stress index (OSI) in patients with severe serum 25(OH)D deficiency as compared to those with 25(OH)D over 20 ng/mL (TOS: p = 0.007, OSI: p = 0.008); and 25(OH)D had a negative indirect effect on TOS by body mass index (BMI), but BMI was not a significant mediator of the studied relationship. In a setting of overweight and increasing degree of obesity, patients with T2DM did not display decreasing values of 25(OH)D. Subjects with the lowest values of 25(OH)D presented the highest values of BMI. Patients with 25(OH)D deficiency were more insulin resistant and showed increased OS but no elevated systemic inflammation. The negative effect of 25(OH)D on TOS did not seem to involve BMI as a mediator.

Moderator role of vitamin D concentrations on the association between metabolic syndrome and C-reactive protein among adults

OBJECTIVE

To evaluate the association between MetS, its components and insulin resistance (IR) with 25(OH)D and hsCRP. The moderator role of 25(OH)D in the association of MetS, its diagnostic components and IR with hsCRP were also explored.

METHODS

A cross-sectional study (2014/2015) with a population-based cohort in Southern Brazil (n = 605). Metabolic syndrome (MetS) diagnosis was defined based on the Joint Interim Statement, while the Homeostasis Model Assessment of insulin resistance (IR) (HOMA-IR) was used for determining IR. Serum concentrations of 25-hydroxy vitamin D [25(OH)D] (ng/mL) and high sensitivity C-reactive protein (hsCRP) (mg/L) were evaluated following standard protocols. 25(OH)D was categorized as sufficiency (>30 ng/mL), insufficiency (20-30 ng/mL) or deficiency (<20 ng/mL) to test its moderator role. Multiple linear regression was used to test the associations. The results were adjusted for possible confounders.

RESULTS

Hypertriglyceridemia and IR were associated with lower 25(OH)D concentrations. However, except for systolic blood pressure, other MetS components and IR were associated with higher hsCRP. The association between elevated waist circumference (WC) and hsCRP was moderated by the 25(OH)D concentrations. The hsCRP median concentrations were more than two times higher among those with elevated WC and 25(OH)D insufficiency or deficiency. In this study, inadequate concentrations of 25(OH)D increased the adverse relationship between elevated WC and inflammation. 25(OH)D concentrations could be incorporated into the clinical protocols for monitoring individuals with abdominal obesity to identify those at a higher risk of complications.

Vitamin D Deficiency and Risk of Metabolic Syndrome in Aging Men

The elderly population is rapidly increasing; hence, the disability due to age-related diseases has become an important socioeconomic burden. Amongst age-related diseases cardiovascular ones (CVD) have a huge impact on morbidity and mortality and are associated with metabolic syndrome (MetS). Several studies investigated the role of hypovitaminosis D in the pathogenesis of MetS and of CVD, this review unravels the relationship between aging/senescence, vitamin D, gender, and pathogenesis of MetS.

Effect of Hypovitaminosis D on Lipid Profile in Hypothyroid Patients in Saudi Arabia

Background

Hypothyroidism is believed to be associated with dyslipidemia and is considered a risk factor for the development of atherosclerotic cardiovascular diseases (ASCVD). Vitamin D, due to its steroid hormone action, retains cell function and controls the metabolism of lipids. Therefore, the present study was carried out to show the association of the risk factors of ASCVD and deficiency of thyroid hormones and vitamin D levels since no previous studies have been performed on Saudi patients before. Methodology. A retrospective cohort study was carried out on 400 hypothyroid patients. Medical records of those patients were followed up and were classified as normal and hypothyroid patients according to their thyroid-stimulating hormone levels. TSH, vitamin D, and lipid profiles were determined using the ELISA technique.

Result

Total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels were significantly higher in hypothyroid patients than those in the normal group. We have found a significant correlation between TSH levels and the risk factors of ASCVD (total cholesterol, triglycerides, and LDL-C). Moreover, a significant correlation between vitamin D levels and the risk factors of ASCVD (total cholesterol, triglycerides, and LDL-C) has been found. In addition, there is a correlation between deficiency of Vit D and low-TSH levels (95% CI 1.092-4.05) indicating a higher risk for the development of ASCVD among those patients.

Conclusion

Hypothyroid and vitamin D-deficient patients must be screened regularly at an early stage to predict and also to prevent cardiovascular diseases. Moreover, an adequate supply of vitamin D and TH should be given to those patients to prevent cardiovascular diseases at an early stage.

The Relationship between Low 25-Hydroxyvitamin D and Cardio-Metabolic Risk Factors among Ellisras Young Adults

Introduction: 25-hydroxyvitamin D (25(OH)D) is found in circulating blood and is regarded as an estimate of vitamin D status. Low circulating 25(OH)D levels are associated with a high body mass index (BMI), increased weight and the increased development of adipose tissue. This study aimed to determine the relationship between low 25(OH)D and cardio-metabolic risk factors among Ellisras young adults. Materials and methods: This is a cross-sectional study that took place in a rural area at Ellisras in Limpopo Province South Africa. The study included 631 young adults (327 females and 304 males) aged between 20 and 29 years. Anthropometric measurements including height, weight and waist circumference were measured following standard procedures. Blood pressure, pulse pressure and blood parameters including fasting plasma glucose, total cholesterol and triglycerides were also measured. Correlations and linear regression were performed to determine the relationship between low 25(OH)D and cardio-metabolic risk factors. Results: Descriptive statistics showed significant (p < 0.05) mean difference of LDL, HDL and blood pressure between males and females. There was a significant association between low 25(OH)D and WC (p = 0.010) based on Spearman correlation. There was no association found between low 25(OH)D and HDL in all models (B ranges from 0.072 to 0.075). There was also no association found between low 25(OH)D and systolic blood pressure (SBP) in all models (B ranges from −0.009 to −0.024). Conclusion: Low 25(OH)D was correlated with WC, and therefore with adiposity. Knowledge of the associations between 25(OH)D deficiency and cardio-metabolic risk before the development of the disease is therefore important to establish whether 25(OH)D supplementation can be used for the prevention of these conditions. Educational programmes should be implemented to educate the communities and the nation at large on how to prevent 25(OH)D deficiency.

Association Between Cardiovascular Risk Factors and 25(OH)D Levels in Obese Patients

Background: Obesity is associated with lower levels of 25-hydroxyvitamin D [25(OH)D] and higher cardiovascular risk related to metabolic syndrome (MetS). Our purpose was to investigate if there is an association between levels of 25(OH)D and the components of MetS in an obese sample. Methods: This cross-sectional study enrolled obese patients referred for bariatric surgery in a specialized clinic. Secondary data were gathered as follows: glycemic and lipid profiles, 25(OH)D, anthropometric parameters, and clinical and sociodemographic information. The results were presented as means (standard deviations) or medians and interquartile intervals or absolute and relative frequencies. The patients were divided into three groups based on 25(OH)D terciles for analysis and were compared using ANOVA, Kruskal-Wallis or chi-squared tests. The correlations were calculated by Spearman's or Pearson's correlation tests. Results: We studied 299 patients, with the majority being women (74.9%). The patients' average (SD) age and 25(OH)D level were 36 (9) years and 25.8 (7.5) ng/mL, respectively. There was no association between vitamin D and MetS or its components. A progressive decrease in total cholesterol, low-density lipoprotein cholesterol (LDL-c), and nonhigh-density lipoprotein cholesterol (HDL-c) was observed as the serum vitamin D level increased, although only the latter reached statistical significance (P = 0.033). The correlation analysis showed a negative linear association between 25(OH)D and total cholesterol (r = -0.157; P = 0.047), 25(OH)D and LDL-c (r = -0.164; P = 0.038), and 25(OH)D and non-HDL-c (r = -0.176; P = 0.026). Conclusions: There was a negative correlation between 25(OH)D levels and the atherogenic profile but none with the MetS.

Differences in the Association Among the Vitamin D Concentration, Dietary Macronutrient Consumption, and Metabolic Syndrome Depending on Pre- and Postmenopausal Status in Korean Women: A Cross-Sectional Study

BACKGROUND AND OBJECTIVES

To assess whether the consumption of dietary macronutrient could change metabolic syndrome (MetS) related to vitamin D deficiency according to menopausal status.

METHODS AND STUDY DESIGN

In a cross-sectional study of 8326 Korean women from the Korean National Health and Nutrition Examination Survey V (2010-2012), we investigated the combined interaction effect of serum 25-hydroxyvitamin D [25(OH)D] concentration and menopausal status on MetS-related variables.

RESULTS

The prevalence rates of 25(OH)D deficiency (vitamin D <50 nmol/L) among premenopausal and postmenopausal women were 84.5% and 67.9%, respectively. Significant differences in MetS-related variables such as body mass index (P<0.001), waist circumference (P=0.005), fast glucose (P=0.048), triglycerides (P=0.001), and high-density lipoprotein cholesterol (P=0.027) based on 25(OH)D concentration were observed among postmenopausal women but not among premenopausal women. Among the postmenopausal women with high consumption of dietary carbohydrate, the adjusted odds ratios (ORs) [95% confidence intervals (95% CIs)] of MetS among participants with 25(OH)D deficiency increased 1.380-fold (95% CI = 1.086-1.753) using the 25(OH)D-sufficient group as a reference. In contrast, the participants with 25(OH)D deficiency showed an increased risk of MetS [OR (95% CI) = 1.313 (1.041-1.655)] with low-fat consumption. However, the aforementioned findings did not differ among premenopausal women.

CONCLUSION

Thus, MetS due to 25(OH)D deficiency among postmenopausal women may be modified by the consumption of dietary macronutrient.

The Association of Serum Vitamin D Deficiency and Metabolic Risk Factors in Chinese Adults with Prediabetes: A Cross-Sectional Study

The association of serum vitamin D deficiency and metabolic risk factors in Chinese adults with prediabetes (PreDM) has not been investigated. The present study aimed to investigate the association of serum vitamin D deficiency and metabolic risk factors in Chinese adults with PreDM. In this cross-sectional study, we stratified 412 PreDM patients into vitamin D sufficient, vitamin D insufficient and vitamin D deficient subgroups. The physical examination data was collected. Serum 25-hydroxyvitamin D₃ [25(OH)D₃] were measured by high performance liquid chromatography. The prevalence of vitamin D deficiency and insufficiency in PreDM patients were 30.58% and 26.70%, respectively. Compared with the vitamin D deficient group, the prevalence of metabolic syndrome, central obesity, hyperglycemia and hypertension were higher than those in the vitamin D insufficient or sufficient group (p<0.05). Moreover, the prevalence of dyslipidemia in the vitamin D deficient group was higher than those in the vitamin D sufficient group (p<0.05). We observed an inverse relationship between 25(OH)D₃ levels and waist circumference, triglyceride, and serum uric acid (β=-0.315; β=-0.134; β=-0.239), a positive relationship between 25(OH)D₃ levels and high-density lipoprotein cholesterol (β=0.197) after adjusting for age, sex and body mass index. Vitamin D deficiency is very common among PreDM patients in China and this deficiency is related to metabolic risk factors.

Correlation of selected stress associated factors with vitamin D deficiency in Jordanian men and women

Background: To identify stress associated factors for vitamin D deficiency (VDD) in healthy Jordanian people based on serum 25(OH)D levels.

Design: Prospective cohort study.

Methods: Three hundred and seventy-one Jordanian men and women aged 17–52 years, who were identified as VD deficient 25(OH)D <30 ng/mL, were eligible to participate in the study. Serum vitamin 25(OH) D was measured using chemiluminescent immunoassay. Cortisol, parathyroid hormone, calcium, phosphate, fasting lipid profile, and blood glucose were also analyzed. Questionnaires were used to collect lifestyles parameters. Anthropometric parameters including: body mass index (BMI), waist (W) and hip (H) circumferences, W/H ratio (WHR) were also calculated.

Results: The vast majority (91%) of the participants had vitamin D deficiency (25- (OH) D <30 ng/mL). Positive correlations were observed between vitamin D deficiency and the following anthropometric parameters in all study sample; gender (P=0.010), height (P=0.22), height/hip ratio (P=0.015) and waist/hip ratio (P=0.013). Lifestyle parameters that indicated very weak positive correlations with VDD were number of family members (P=0.011) and insufficient exposure to sunlight (P=0.023). The following clinical parameters showed weak or very weak correlations with VDD; serum cortisol (r=0.318), low density lipoprotein (r=0.246) and total cholesterol (r=0.133). Skin color and water pipe tobacco smoking were added to the multivariable stepwise regression analyses as they have been weakly correlated with VDD. These predictors together explained only 12.2% of the variance in serum cortisol levels in the VDD study sample.

Conclusion: A weak positive association between VDD and elevated serum cortisol was observed in this study. Subcutaneous changes may be involved in that association but further studies are needed to clarify a potential role for adrenocorticotropic hormone (ACTH).

Systematic thyroid screening in myotonic dystrophy: link between thyroid volume and insulin resistance

Background

Myotonic dystrophy (DM1), a neuromuscular disease related to DMPK gene mutations, is associated to endocrine disorders and cancer. A routine endocrine work-up, including thyroid ultrasound (US), was conducted in 115 genetically-proven DM1 patients in a neuromuscular reference center. The aim of this study was to determine the prevalence and the causes of US thyroid abnormalities in DM1.

Results

In the whole population (age 45.1 ± 12.2 years, 61.7% female), palpable nodules or goiters were present in 29.2%. The percentage of US goiter (thyroid volume > 18 mL) and US nodules were, respectively, 38.3 and 60.9%. Sixteen of the 115 patients had a thyroidectomy, after 22 fine-needle aspiration cytology guided by thyroid imaging reporting and data system (TIRADS) classification. Six micro- (1/6 pT3) and 3 macro-papillary thyroid carcinoma (PTCs) (2/3 intermediate risk) were diagnosed (7.9% of 115). Thyroid US led to the diagnosis of 4 multifocal and 2 unifocal (including 1 macro-PTC) non-palpable PTCs. Ultrasound thyroid volume was positively correlated to body mass index (BMI) (p = 0.015) and parity (p = 0.036), and was inversely correlated to TSH (p < 0.001) and vitamin D levels (p = 0.023). The BMI, the frequencies of glucose intolerance and PTC were significantly higher in UsGoiter versus non-UsGoiter groups.

Conclusion

In this systematically screened DM1 cohort, the frequency of UsGoiter, mainly associated to BMI, was about 40%, US nodules 60%, thyroidectomies 13–14%, and PTCs 8%, two-thirds of them being micro-PTCs with good prognosis. Therefore, a systematic screening remains debatable. A targeted US screening in case of clinical abnormality or high BMI seems more appropriate.

Electronic supplementary material

The online version of this article (10.1186/s13023-019-1019-3) contains supplementary material, which is available to authorized users.

Vitamin D and cardiometabolic disorders: a review of current evidence, genetic determinants and pathomechanisms

Vitamin D deficiency has been implicated in the pathophysiology of cardiometabolic disorders including obesity, type 2 diabetes mellitus, cardiovascular diseases and polycystic ovary syndrome. Despite a large number of experimental and observational studies supporting a role for vitamin D in these pathologies, randomized controlled trials have reported little to no effect of vitamin D supplementation in the prevention or treatment of these disorders, although some results remain ambiguous. Polymorphisms in genes related to vitamin D metabolism, particularly in the vitamin D receptor and binding protein and the metabolizing enzyme 1-α-hydroxylase, have emerged as potential contributors to these divergent results. It is now becoming increasingly recognized that the effects and potential benefits of vitamin D supplementation may vary by several factors including vitamin D deficiency status, ethnicity and/or the presence of genetic variants, which affect individual responses to supplementation. However, these factors have seldom been explored in the available literature. Future trials should consider inter-individual differences and, in particular, should aim to clarify whether certain subgroups of individuals may benefit from vitamin D supplementation in the context of cardiometabolic health.

Higher serum levels of vitamin D are associated with lower blood glucose levels

OBJECTIVE

Vitamin D plays an important role in bone metabolism. There is now evidence that a higher serum level of 25-hydroxyvitamin D (25[OH]D) is associated with a lower risk of developing type 2 diabetes mellitus, because it provides better glycemic control, possibly by promoting greater insulin sensitivity, and also by improving pancreatic beta cell function. The objective of the present study was to evaluate the possible association between 25(OH)D sufficiency and glycemia.

METHODS

This was a cross-sectional study involving 680 women, 35 to 74 years of age, selected through systematic sampling. From each participant, fasting blood samples were collected for the determination of 25(OH)D and glucose levels.

RESULTS

The mean fasting blood glucose level was 105 mg/dL (range 26-401 mg/dL). Fasting serum levels of 25(OH)D were <30 ng/mL in 65.4% of the participants and <20 ng/mL in 25.6%. A serum 25(OH)D level <30 ng/mL was positively associated with a blood glucose level ≥100 mg/dL (odds ratio [OR] 1.29, 95% confidence interval [CI] 1.05-1.57), as was a serum 25(OH)D level <20 ng/mL (OR 1.25, 95% CI 1.04-1.50).

CONCLUSIONS

Lower serum 25(OH)D concentrations appear to be associated with a high blood glucose levels.

Vitamin D Is Inversely Related to Obesity: Cross-Sectional Study in a Small Cohort of Serbian Adults

Objective: Vitamin D (vitD) mediates numerous health conditions other than bone health and mineralization. Its role in cardiometabolic condition is still inconclusive. Methods: We conducted a cross-sectional study in 87 apparently healthy Serbian adults. We assessed their dietary intake, anthropometric and biochemical parameters, blood pressure, and vitD status (as serum 25-hydroxyvitamin D, 25(OH)D). Unexpectedly, the status was significantly higher in January than in July. Therefore, we pooled the data from two time points, to enhance the statistical power for carrying out association analyses. We employed linear regression models to evaluate the associations between vitD status and the obesity biomarkers of serum lipids and blood pressure. Results: Mean vitD intake of 3.85 ± 4.71 μg in the cohort was below recommended. Of the subjects in the pooled cohort, 60.58% were vitD deficient (with serum 25(OH)D below 50 nmol/L), with the majority of them being women who were overweight. VitD status tended to be inversely related to percent body fat and waist/height ratio in the crude regression model. After age and gender adjustment, the status was significantly related to waist circumference, waist/height ratio, and waist/hip ratio (β = -0.116, 95% confidence interval [CI]: -0.206, -0.025, β = -0.001, 95% CI: -0.001, 0.000, and β = -0.001, 95% CI: -0.001, 0.000, respectively). These associations remained only within women. Fully adjusted models supported the notion of vitD being independently associated with central adiposity, regardless of age, gender, and total obesity. Conclusions: In apparently healthy adults with low vitD intake, vitD status was inversely associated with obesity parameters, pronouncedly in women. Our data support the need for development and implementation of public health policies on increasing vitD intake also as part of obesity management strategies.

Vitamin D supplementation may improve back pain disability in vitamin D deficient and overweight or obese adults

Back pain is currently the greatest cause of disability worldwide, and there are very limited therapeutic options available. Vitamin D deficiency and obesity are both risk factors for back pain. The few randomised controlled trials examining the effects of vitamin D supplementation on back pain have methodological limitations and largely include non-vitamin D deficient participants. Thus, the aim of this study was to determine whether vitamin D supplementation improves back pain symptoms in vitamin D deficient and overweight or obese, otherwise healthy adults. Sixty-five overweight or obese adults (BMI ≥ 25 kg/m²) with vitamin D deficiency (25-hydroxyvitamin D [25(OH)D] concentrations ≤50 nmol/L) were randomised to a bolus oral dose of 100,000 IU followed by 4000 IU cholecalciferol/day or matching placebo for 16 weeks. We measured 25(OH)D concentrations (chemiluminescent immunoassays) and self-reported back pain (Chronic Pain Grade Questionnaire) before and after the intervention. Lifestyle habits including sun exposure, physical activity, and diet were collected using questionnaires. Fifty-four participants completed the study, of which 49 had complete data for back pain and were included in the present analyses (31 M/18 F; mean ± SD age: 31.8 ± 8.9 years; BMI: 31.1 ± 4.5 kg/m²). After the 16-week intervention, 25(OH)D levels increased significantly with vitamin D supplementation compared with placebo (55.7 ± 20.9 versus 3.9 ± 14.4 nmol/L, respectively, p < 0.001). There were no significant differences between vitamin D and placebo groups in change in back pain intensity or disability scores (all p > 0.05). However, in those with 25(OH)D concentrations <30 nmol/L at baseline (n = 20), there was a significantly greater reduction in back pain disability scores in the vitamin D group compared with placebo, after adjusting for important covariates known to affect vitamin D status and/or back pain (b [95%CI] = -11.6 [-22.4, -0.8], p = 0.04). Our findings suggest that vitamin D supplementation in overweight or obese and markedly vitamin D deficient adults (25(OH)D <30 nmol/L) may improve back pain disability. Although treating severe vitamin D deficiency is recommended for optimising bone health, this study suggests it may also improve back pain. Hence, testing for vitamin D deficiency in those with back pain who are overweight or obese may be warranted.

Overfed but undernourished: recognizing nutritional inadequacies/deficiencies in patients with overweight or obesity

Overweight and obesity are highly prevalent throughout the world and can adversely affect the nutritional status of individuals. Studies have shown that many people with obesity have inadequate intake of iron, calcium, magnesium, zinc, copper, folate and vitamins A and B₁₂, likely as a result of poor diet quality. Nutritional inadequacies or deficiencies may also occur due to altered pharmacokinetics in the individual with obesity and due to interactions in those with overweight or obesity with various pharmaceuticals. However, it has been demonstrated that the adult population in the United States as a whole is deficient in certain micronutrients as a result of the availability and overconsumption of high-calorie, low-nutrient processed foods. Poor nutrition may contribute to the development of certain chronic conditions, such as type 2 diabetes, which is already more prevalent in those with obesity. Clinicians need to be aware of these gaps, particularly in those individuals with obesity who are undergoing bariatric surgery or taking pharmaceutical products long term to facilitate weight loss. Patients with overweight or obesity likely struggle to achieve a balanced diet and may benefit from consultation with a dietitian. Along with providing recommendations for healthy eating and exercise, supplementation with specific micronutrients or multivitamins should be considered for individuals at the highest risk for or with established deficiencies. Further research is needed to understand the factors underlying nutritional inadequacies in individuals with overweight or obesity, as well as the outcomes of treatment strategies employed to address them.

Fat-soluble micronutrients and metabolic syndrome

PURPOSE OF REVIEW

Metabolic syndrome (MetS) is associated with increased risk of obesity, type 2 diabetes mellitus and cardiovascular diseases. MetS prevalence has been associated with diet inadequacy. Conversely, the cumulative incidence of MetS has been inversely associated with a Mediterranean-style diet that includes many different health-beneficial nutrients. Adherence to a Mediterranean-style diet could reduce or at least stabilize metabolic risk factors.

RECENT FINDINGS

Low serum level of fat-soluble micronutrients, such as carotenoids, vitamin (vit) A, D and E, has been linked to MetS. Fat-soluble micronutrients could contribute to prevent MetS thanks to their antioxidant and anti-inflammatory properties (vit E, carotenoids) or to their central role as hormone regulators (vit D) and/or lipid metabolism and glucose homeostasis sensors (vit D and E).

SUMMARY

This review summarizes recent epidemiological studies linking fat-soluble micronutrients to MetS and highlights new evidence on their mechanisms of actions.

The Role of Toll-Like Receptors and Vitamin D in Cardiovascular Diseases-A Review

Cardiovascular diseases are the leading cause of mortality worldwide. Therefore, a better understanding of their pathomechanisms and the subsequent implementation of optimal prophylactic and therapeutic strategies are of utmost importance. A growing body of evidence states that low-grade inflammation is a common feature for most of the cardiovascular diseases in which the contributing factors are the activation of toll-like receptors (TLRs) and vitamin D deficiency. In this article, available data concerning the association of cardiovascular diseases with TLRs and vitamin D status are reviewed, followed by a discussion of new possible approaches to cardiovascular disease management.

Vitamin D insufficiency/deficiency is associated with insulin resistance in Brazilian children, regardless of body fat distribution

OBJECTIVE

To assess the prevalence of vitamin D insufficiency and deficiency and its association with cardiometabolic risk factors, controlled by adiposity, in a representative sample of prepubescent children.

DESIGN

Cross-sectional population-based study. Body composition was evaluated by dual-energy X-ray absorptiometry. Anthropometric measures and blood pressure were performed. Laboratory analyses were performed to determine the levels of vitamin D (25-hydroxyitamin D; 25(OH)D), glucose, insulin, serum lipids and intact parathyroid hormone. Dietary intake was assessed by three 24 h recalls.

SETTING

Viçosa, Minas Gerais, Brazil, 2015.

SUBJECTS

Representative sample of 378 children aged 8 and 9 years from urban schools.

RESULTS

Inadequate serum concentrations of 25(OH)D were diagnosed in more than half of the children and none of them met the recommended vitamin D intake. After adjusting for confounding factors in the multiple regression analysis, lower prevalence of insulin resistance and hypertriacylglycerolaemia was found in children with serum 25(OH)D levels ≥75 nmol/l (prevalence ratio=0·25; 95 % CI 0·08, 0·85) and ≥50 nmol/l (prevalence ratio=0·61; 95 % CI 0·37, 0·99), respectively. However, after adjusting for different indicators of adiposity, insulin resistance remained independently associated and the association with hypertriacylglycerolaemia was lost after adjusting for central adiposity. The prevalence of vitamin D insufficiency/deficiency was associated with the number of cardiometabolic alterations in children.

CONCLUSIONS

The study results showed that prevalence of vitamin D insufficiency/deficiency was high among the children and insulin resistance was the main cardiometabolic alteration associated with this condition, even in a tropical climate country such as Brazil.

Plasma 25-Hydroxyvitamin D Is Related to Protein Signaling Involved in Glucose Homeostasis in a Tissue-Specific Manner

Vitamin D has been suggested to play a role in glucose metabolism. However, previous findings are contradictory and mechanistic pathways remain unclear. We examined the relationship between plasma 25-hydroxyvitamin D (25(OH)D), insulin sensitivity, and insulin signaling in skeletal muscle and adipose tissue. Seventeen healthy adults (Body mass index: 26 ± 4; Age: 30 ± 12 years) underwent a hyperinsulinemic-euglycemic clamp, and resting skeletal muscle and adipose tissue biopsies. In this cohort, the plasma 25(OH)D concentration was not associated with insulin sensitivity (r = 0.19, p = 0.56). However, higher plasma 25(OH)D concentrations correlated with lower phosphorylation of glycogen synthase kinase-3 (GSK-3) α^Ser21 and β^Ser9 in skeletal muscle (r = −0.66, p = 0.015 and r = −0.53, p = 0.06, respectively) and higher GSK-3 α^Ser21 and β^Ser9 phosphorylation in adipose tissue (r = 0.82, p < 0.01 and r = 0.62, p = 0.042, respectively). Furthermore, higher plasma 25(OH)D concentrations were associated with greater phosphorylation of both protein kinase-B (Akt^Ser473) (r = 0.78, p < 0.001) and insulin receptor substrate-1 (IRS-1^Ser312) (r = 0.71, p = 0.01) in adipose tissue. No associations were found between plasma 25(OH)D concentration and IRS-1^Tyr612 phosphorylation in skeletal muscle and adipose tissue. The divergent findings between muscle and adipose tissue with regard to the association between 25(OH)D and insulin signaling proteins may suggest a tissue-specific interaction with varying effects on glucose homeostasis. Further research is required to elucidate the physiological relevance of 25(OH)D in each tissue.