Vitamin D regulation of adipogenesis and adipose tissue functions

The impact of vitamin D status on lipid profiles and atherogenic dyslipidemia markers in children and adolescents with obesity

BACKGROUND AND AIM

Adequate serum vitamin D levels correlate with a more favorable lipid profile compared to deficient levels. Despite the well-established prevalence of vitamin D deficiency in children with obesity, studies investigating its influence on lipid profiles in this population are scarce. We explored the impact of vitamin D status on lipid profiles and markers of atherogenic dyslipidemia in a cohort of children and adolescents with obesity.

METHODS AND RESULTS

A total of 271 Caucasian children and adolescents with overweight/obesity and a control group of 54 pediatric patients with normal weight. All participants underwent outpatient visits for the assessment of clinical parameters and venous blood collection for biochemical analysis such as triglycerides (TG)/HDL-C ratio, LDL-C/HDL-C ratio, atherogenic index of plasma AIP), vitamin D level. Individuals with obesity displayed severe vitamin D deficiency (25-OH-D ≤10 ng/ml) at a higher frequency compared to those with normal weight (p = 0.03). In patients with overweight/obesity and low 25-OH-D levels show higher values of glycemia (p = 0.001), insulin resistance (HOMA-IR and TRYG p < 0.001), TG (p < 0.001), TG/HDL-C (p = 0.001), AIP (p < 0.001), SBP (p = 0.01), and DBP (p = 0.04). In normal-weight individuals with low 25-OH- D levels an increased values of glycemia (p = 0.01), insulin resistance (HOMA-IR p = 0.01 and TRYG p = 0.002), TG (p = 0.01), TG/HDL-C (p = 0.02), AIP (p = 0.01). A direct correlation between 25-OH-D levels and metabolic parameters is observed.

CONCLUSIONS

A correlation between vitamin D levels and the lipid/atherosclerotic profile was recorded. Vitamin D deficiency may represent a preventable and easily treatable cardiometabolic risk factor, emphasizing the importance of early intervention and preventive measures.

Serum vitamin D and obesity among US adolescents, NHANES 2011-2018

Background and objectives

Childhood obesity is highly prevalent worldwide. We aimed to assess whether serum 25-hydroxyvitamin D was associated with general/central obesity among US adolescents, and further to explore the mediatory impact of homeostasis model assessment of insulin resistance (HOMA-IR) on this association.

Methods

This study is cross-sectional in design. Study adolescents were enrolled from the National Health and Nutrition Examination Survey (NHANES), 2011-2018. Serum 25-hydroxyvitamin D categories associated with general (indexed by body mass index) and central (indexed by waist circumference to height ratio) obesity were regressed. The possible mediatory effect of HOMA-IR on this association was explored. The nonlinear and dose-response association was examined by restricted cubic spline (RCS) test.

Results

Total 2,696 adolescents were eligible for inclusion, and the mean age of all adolescents was 15.4 years. Overall, the percentage of general and central obesity was 38.0% and 38.6%, respectively. Compared with adolescents with sufficient vitamin D, adolescent with deficient and insufficient vitamin D intake were associated with general obesity and central obesity; fully-adjusted OR for general obesity was 1.602 (95% CI: 1.161-2.211) and 1.659 (1.385-1.986), and fully-adjusted OR for central obesity was 2.025 (1.445-2.837) and 1.557 (1.287-1.884), respectively, while there was no observable significance in adolescents with possibly harmful vitamin D. The proportion mediated by HOMA-IR was estimated to be 31.7% for global obesity and 50.3% for central obesity (both P < 0.05). More stratified analyses were presented, and identified that the association with general obesity was particularly present among Mexican American, while with central obesity among Non-Hispanic Black adolescents.

Conclusions

Our findings indicate that deficient or insufficient 25-hydroxyvitamin D concentrations were associated with the significant risk of general and central obesity among US adolescents, and approximately 30% and 50%, respectively, of these associations were mediated by HOMA-IR.

Calcium, Phosphate, and Vitamin D in Children and Adolescents with Chronic Diseases: A Cross-Sectional Study

Chronic diseases may affect the nutritional status of children and adolescents. Calcium (Ca), phosphorus (P), and vitamin D (Vit-D) are crucial nutrients for their growth and development. Proper diagnosis and treatment are critical components of personalized and precision medicine. Hence, we conducted a cross-sectional and comparative study to evaluate Ca, P, and Vit-D levels in their non-skeletal functions and their association with health and nutritional biomarkers in children and adolescents with diverse chronic conditions. We performed anthropometric, body composition, clinical evaluation, biochemical analysis, and dietary survey methods. A total of 78 patients (1-19 years, 43 females, 42 children) took part in this study. Overall, 24, 30, and 24 participants were obese, undernourished, and eutrophic, respectively. Results found that 74% and 35% of individuals had deficient Vit-D and Ca intake, respectively. Most cases were normocalcemic. Results also found that 47% of the subjects had Vit-D deficiency (VDD), 37% were insufficient, and 37% had hypophosphatemia. Of the 46% and 31% of patients with VDD and insufficient levels, 19% and 11% were hypophosphatemic, respectively. Calcium, P, and Vit-D levels were associated with anthropometric parameters, body mass index, body composition, physical activity, diet, growth hormones, and the immune, liver, and kidney systems. These results show the coincident risk of altered Ca, P, and Vit-D metabolism in children and adolescents with chronic diseases.

Influence of vitamin D supplementation on growth, body composition, pubertal development and spirometry in South African schoolchildren: a randomised controlled trial (ViDiKids)

OBJECTIVE

To determine whether weekly oral vitamin D supplementation influences growth, body composition, pubertal development or spirometric outcomes in South African schoolchildren.

DESIGN

Phase 3 double-blind randomised placebo-controlled trial.

SETTING

Socioeconomically disadvantaged peri-urban district of Cape Town, South Africa.

PARTICIPANTS

1682 children of black African ancestry attending government primary schools and aged 6-11 years at baseline.

INTERVENTIONS

Oral vitamin D3 (10 000 IU/week) versus placebo for 3 years.

MAIN OUTCOME MEASURES

Height-for-age and body mass index-for-age, measured in all participants; Tanner scores for pubertal development, spirometric lung volumes and body composition, measured in a subset of 450 children who additionally took part in a nested substudy.

RESULTS

Mean serum 25-hydroxyvitamin D3 concentration at 3-year follow-up was higher among children randomised to receive vitamin D versus placebo (104.3 vs 64.7 nmol/L, respectively; mean difference (MD) 39.7 nmol/L, 95% CI 37.6 to 41.9 nmol/L). No statistically significant differences in height-for-age z-score (adjusted MD (aMD) -0.08, 95% CI -0.19 to 0.03) or body mass index-for-age z-score (aMD -0.04, 95% CI -0.16 to 0.07) were seen between vitamin D versus placebo groups at follow-up. Among substudy participants, allocation to vitamin D versus placebo did not influence pubertal development scores, % predicted forced expiratory volume in 1 s (FEV1), % predicted forced vital capacity (FVC), % predicted FEV1/FVC, fat mass or fat-free mass.

CONCLUSIONS

Weekly oral administration of 10 000 IU vitamin D3 boosted vitamin D status but did not influence growth, body composition, pubertal development or spirometric outcomes in South African schoolchildren.

TRIAL REGISTRATION NUMBERS

ClinicalTrials.gov NCT02880982, South African National Clinical Trials Register DOH-27-0916-5527.

Vitamin D was Superior to Omega-3 as a Simvastatin Adjuvant in Improving Blood Lipids and Atherogenic Index in Type-I Dyslipidemic Rats

Objectives

Adjuvant therapy is often used to optimize the antihyperlipidemic effect of simvastatin. Omega-3 and vitamin D supplementation are recommended as adjuvant therapies to low-intensity statins. This study aimed to compare the effects of vitamin D and omega-3 as adjuvant therapy to simvastatin to improve the lipid profiles and atherogenic index of plasma (AIP) in type-I dyslipidemic rats.

Materials and Methods

Thirty-six male rats were randomized and divided into six groups: healthy control, dyslipidemic rats with no treatment, and dyslipidemic rats treated with either low-dose simvastatin only or omega-3 or vitamin D at low and high doses. Dyslipidemia was induced with high-fat diets for four weeks, followed by treatment for the next two weeks. Blood samples were withdrawn before and after simvastatin treatment. In addition, aspartate transaminase (AST) and alanine transaminase (ALT) levels were analyzed to assess liver function.

Results

Administration of a high-fat diet-induced type 1 dyslipidemia and increased ALT levels (p < 0.05). Treatment with low-dose simvastatin did not significantly improve triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDLc) or non-HDLc levels. When combined with a high-dose vitamin D, simvastatin significantly reduced TG and increased HDLc levels (p < 0.05), thereby improving AIP levels. This improvement was not observed in rats treated with omega-3 or vitamin D at a lower dose.

Conclusion

We concluded that high-dose vitamin D as an adjuvant to simvastatin therapy was superior to omega-3 in improving TG, HDL, and AIP levels. High-dose vitamin D also improved ALT levels in type-I dyslipidemic rats. This result may be translated in clinics to reduce the risk of coronary syndrome in patients with type-I dyslipidemia.

Interplay between Vitamin D and Adipose Tissue: Implications for Adipogenesis and Adipose Tissue Function

Adipose tissue encompasses various types, including White Adipose Tissue (WAT), Brown Adipose Tissue (BAT), and beige adipose tissue, each having distinct roles in energy storage and thermogenesis. Vitamin D (VD), a fat-soluble vitamin, maintains a complex interplay with adipose tissue, exerting significant effects through its receptor (VDR) on the normal development and functioning of adipocytes. The VDR and associated metabolic enzymes are widely expressed in the adipocytes of both rodents and humans, and they partake in the regulation of fat metabolism and functionality through various pathways. These encompass adipocyte differentiation, adipogenesis, inflammatory responses, and adipokine synthesis and secretion. This review primarily appraises the role and mechanisms of VD in different adipocyte differentiation, lipid formation, and inflammatory responses, concentrating on the pivotal role of the VD/VDR pathway in adipogenesis. This insight furnishes new perspectives for the development of micronutrient-related intervention strategies in the prevention and treatment of obesity.

Factors Associated with Vitamin D Deficiency and Their Relative Importance among Indian Adolescents: An Application of Dominance Analysis

Vitamin D deficiency is a serious issue in developing nations, including India. This study investigates the determinants of vitamin D deficiency among Indian adolescents and assesses their relative importance using dominance analysis. Data from the Comprehensive National Nutrition Survey (CNNS) conducted between 2016 and 2018 were utilized in this study. Vitamin D levels were assessed based on serum 25-hydroxyvitamin D concentration, with a sample size encompassing 13,065 adolescents aged between 10 and 19 years. Backward stepwise multivariate logistic regression was used to identify the correlates of vitamin D deficiency, and the relative importance of these factors was assessed using dominance analysis. The study identified nine predictors that were significantly associated with vitamin D deficiency at a 1% level of significance (α = 0.001). Among these factors, sex was found to be the most significant predictor, with female adolescents being 2.66 (95% CI: 95% CI: 2.39-2.96) times more likely to be vitamin D deficient compared to male adolescents. Lifestyle and behavioral factors, such as "sex," "wealth index," and "place of residence," were more dominant in predicting vitamin D deficiency than biological indicators like "BMI" and "serum creatinine." This underscores the vital role of sunlight exposure in maintaining sufficient vitamin D levels. In summary, this study sheds light on the multifaceted factors contributing to vitamin D deficiency among Indian adolescents, emphasizing the significance of targeted interventions and public health awareness campaigns to mitigate this pressing issue.

Brown Fat and Nutrition: Implications for Nutritional Interventions

Brown and beige adipocytes are renowned for their unique ability to generate heat through a mechanism known as thermogenesis. This process can be induced by exposure to cold, hormonal signals, drugs, and dietary factors. The activation of these thermogenic adipocytes holds promise for improving glucose metabolism, reducing fat accumulation, and enhancing insulin sensitivity. However, the translation of preclinical findings into effective clinical therapies poses challenges, warranting further research to identify the molecular mechanisms underlying the differentiation and function of brown and beige adipocytes. Consequently, research has focused on the development of drugs, such as mirabegron, ephedrine, and thyroid hormone, that mimic the effects of cold exposure to activate brown fat activity. Additionally, nutritional interventions have been explored as an alternative approach to minimize potential side effects. Brown fat and beige fat have emerged as promising targets for addressing nutritional imbalances, with the potential to develop strategies for mitigating the impact of metabolic diseases. Understanding the influence of nutritional factors on brown fat activity can facilitate the development of strategies to promote its activation and mitigate metabolic disorders.

A Cross-Sectional Study of the Associations between Biomarkers of Vitamin D, Iron Status, and Hemoglobin in South African Women of Reproductive Age: the Healthy Life Trajectories Initiative, South Africa

Background

Vitamin D deficiency and anemia impact the health of women of reproductive age. Evidence suggests an inverse relationship between serum vitamin D (25-hydroxyvitamin D [25(OH)D]) and anemia/iron deficiency, but less is known about these associations in women of reproductive age, in particular in a setting with a combined burden of micronutrient deficiency, food insecurity, and obesity.

Objective

We aimed to assess the associations between 25(OH)D and biomarkers of iron and anemia in a cohort of women of reproductive age from Soweto, South Africa. The prevalence of vitamin D deficiency was also assessed.

Methods

In this cross-sectional substudy of the Healthy Life Trajectories Initiative (HeLTI) South Africa pilot trial, 25(OH)D, iron markers (ferritin and soluble transferrin receptor [sTFR]), and altitude-adjusted hemoglobin (Hb) were measured in 493 women aged 18 to 25 years. Associations between iron deficiency/anemia and vitamin D status were evaluated using multivariable logistic regression, adjusting for confounders including fat mass index (FMI). Structural equation modeling (SEM) was performed to evaluate direct and indirect pathways between 25(OH)D, iron and anemia markers, and covariates.

Results

Of 493 participants, 136 (27.6%) had vitamin D insufficiency (25(OH)D ≥12-20 ng/mL), whereas 28 (5.6%) had vitamin D deficiency (<12 ng/mL). Anemia and iron deficiency were not significantly associated with vitamin D category (25(OH)D<20 ng/mL compared with ≥20 ng/mL) in multivariable logistic regression analyses. In SEM, log-transformed 25(OH)D was not significantly associated with Hb, ferritin, or sTFR, but it was significantly associated with season of data collection, hormonal contraceptive use, and FMI (total effects: B = 0.17, 95% CI: 0.104, 0.236, P < 0.001; B: 0.10, 95% CI: 0.041, 0.154, P < 0.001; B: -0.01, 95%CI: -0.016, -0.003, P = 0.003, respectively).

Conclusion

No significant association between vitamin D (25(OH)D), anemia (Hb), and iron markers was found. The inverse relationship between FMI and vitamin D status emphasizes the overlap between adiposity and micronutrient deficiencies in young South African women, exacerbating their risk of disease development.

Vitamin D Determinants, Status, and Antioxidant/Anti-inflammatory-Related Effects in Cardiovascular Risk and Disease: Not the Last Word in the Controversy

Beyond its key role in calcium homeostasis, vitamin D has been found to significantly affect the cardiovascular (CV) system. In fact, low vitamin D levels have been associated with increased CV risk, as well as increased CV morbidity and mortality. The majority of effects of this molecule are related directly or indirectly to its antioxidative and anti-inflammatory properties. Generally, vitamin D insufficiency is considered for 25-hydroxyvitamin D (25(OH)D) levels between 21-29 ng/mL (corresponding to 52.5-72.5 nmol/L), deficiency as 25(OH)D levels less than 20 ng/mL (<50 nmol/L), and extreme deficiency as 25(OH)D less than 10 ng/mL (<25 nmol/L). However, the definition of an optimal vitamin D status, as defined by 25(OH)D, remains controversial for many extra-bone conditions, including CV disease. In this review, confounding factors affecting the 25(OH)D measurement and status will be discussed. In particular, available evidence on the mechanism and role of vitamin D in relation to CV risk and disease through its antioxidant effect will be reported, also facing the aspect regarding the debate on the minimum blood 25(OH)D level required to ensure optimal CV health.

Evidence That Increasing Serum 25(OH)D Concentrations to 30 ng/mL in the Kingdom of Saudi Arabia and the United Arab Emirates Could Greatly Improve Health Outcomes

Accumulating evidence supports the potential protective effects of vitamin D against chronic diseases such as Alzheimer’s disease, autoimmune diseases, cancers, cardiovascular disease (ischaemic heart disease and stroke), type 2 diabetes, hypertension, chronic kidney disease, stroke, and infectious diseases such as acute respiratory tract diseases, COVID-19, influenza, and pneumonia, as well as adverse pregnancy outcomes. The respective evidence is based on ecological and observational studies, randomized controlled trials, mechanistic studies, and Mendelian randomization studies. However, randomized controlled trials on vitamin D supplementation have largely failed to show benefits, probably due to poor design and analysis. In this work, we aim to use the best available evidence on the potential beneficial effects of vitamin D to estimate the expected reduction in incidence and mortality rates of vitamin D-related diseases in the Kingdom of Saudi Arabia and the United Arab Emirates if minimum serum 25(OH)D concentrations were to be raised to 30 ng/mL. Estimated reductions by 25% for myocardial infarction incidence, 35% for stroke incidence, 20 to 35% for cardiovascular disease mortality, and 35% for cancer mortality rates depicted a promising potential for raising serum 25(OH)D. Methods to increase serum 25(OH)D concentrations at the population level could include food fortification with vitamin D3, vitamin D supplementation, improved dietary vitamin D intake, and sensible sun exposure.

Serum 25-Hydroxy Vitamin D Levels in Children with Acute Respiratory Infections Caused by Respiratory Virus or Atypical Pathogen Infection

We aimed to clarify the involvement of vitamin D status in virus or atypical pathogens infection in children with acute respiratory infections (ARIs). In this retrospective study, 295 patients with ARIs were attacked by a respiratory virus or a single atypical pathogen; 17 patients with ARIs induced by two pathogens, and 636 healthy children were included. Serum 25(OH)D levels of all children were measured. Oropharyngeal samples of the patients for viruses or atypical pathogens were studied by polymerase chain reaction (PCR) or reverse transcription-polymerase chain reaction (RT-PCR). In our studies, 58.98% of the 295 single-infected subjects and 76.47% of the 17 co-infected subjects had 25(OH)D levels below the recommended 50.0 nmol/L; the mean 25(OH)D levels were 48.48 ± 19.91 nmol/L and 44.12 ± 12.78 nmol/L. Low serum 25(OH)D levels were remarkable in patients with one of seven viruses or atypical pathogens infected. These results were significantly different from those in the healthy group. There were no significant differences in 25(OH)D levels between single infection and co-infection groups. There were no differences in severity among means of 25(OH)D levels. Female or >6-year-old children patients with low serum 25(OH)D levels were more vulnerable to pathogenic respiratory pathogens. However, serum 25(OH)D levels may be related to the recovery of ARIs. These findings provide additional evidence for the development of strategies to prevent ARIs in children.

Adiposity and physical activity are among the main determinants of serum vitamin D concentrations in older adults: the EpiFloripa Aging Cohort Study

The identification of factors associated with 25-hydroxycholecalciferol (25(OH)D) concentration can help suggest more specific interventions for older adults. In this cross-sectional study of older adults from southern Brazil, we hypothesized that some sociodemographic, behavioral, and health factors positively or negatively influence the 25(OH)D concentration in this population. This analysis was performed using data from the second wave of the EpiFloripa Aging Cohort Study (2013-2015). Serum 25(OH)D levels were classified according to the guidelines of the Endocrine Society. Multinomial logistic regression was performed to evaluate the relative risks of sociodemographic, behavioral, and health factors in each 25(OH)D category. A total of 574 older adults (aged 63-93 years) participated in this study. The prevalence of insufficiency (21-29 ng/mL) was 43.7% and that of deficiency (≤20 ng/mL) was 23.5%. In the adjusted analysis, female sex, higher levels of low-density lipoprotein cholesterol (LDL-C ≥160 mg/dL), obesity by adiposity (body fat percentage [%fat], male ≥31%; female ≥43%), and body mass index (BMI, >30 kg/m²) presented higher relative risks for insufficiency than for sufficiency. For those with deficiency, the associated factors were female sex, disability in 4 or more activities of daily living (ADLs), LDL-C ≥100 mg/dL, and obesity by %fat and BMI. A protective factor against insufficiency and deficiency was active leisure-time physical activity (PA, ≥150 min/week). Our results demonstrated that being female and having modifiable factors, such as high levels of LDL-C, obesity, and disability on ADLs, were negatively associated with hypovitaminosis D. On the other hand, leisure-time PA was positively associated with adequate serum vitamin D concentration.

The Association of Serum Adipokines, Insulin Resistance and Vitamin D Status in Male Patients with Androgenetic Alopecia

Background

The frequent coexistence of obesity and metabolic syndrome in patients with Androgenetic alopecia (AGA), may indicate a common pathogenetic pathway with adipokines being a possible implicating cytokine.

Objective

This study was conducted to investigate the changes in serum levels of adipokines, insulin resistance, vitamin D status and their relationship with AGA, and the relationship between serum levels of adipokines and insulin resistance.

Methods

80 male patients with AGA were selected as the experimental group and 60 healthy males served as the control group. Both the AGA group and healthy control group were divided into 2 groups according to the presence or absence of insulin resistance (IR): the IR group and the NIR group. Serum levels of leptin, adiponectin, resistin, visfatin, insulin and 25(OH)D were evaluated in all subjects.

Results

Compared with the control group, AGA patients showed higher serum levels of leptin and lower adiponectin/leptin (Adpn/Lep) ratio (P<0.05), and both were positively correlated with the severity of the disease. Compared with the AGA NIR group, serum leptin levels were increased in the AGA IR group (P<0.05). AGA IR group and AGA NIR group possessed lower Adpn/Lep ratio when compared with the healthy IR group and healthy NIR group respectively (P<0.05). The multi-factor logistic regression analysis results showed decreased Adpn/Lep level and increased leptin level as risk factors for AGA. AGA Patients had lower vitamin D levels than healthy controls (P<0.05).

Conclusion

Patients with AGA show an imbalance between pro- and anti-inflammatory adipokines, and probably be involved in AGA pathogenesis. Insulin resistance may influence levels of adipokines, but the present findings cannot indicate insulin resistance plays a role in the onset of AGA. The insufficiency and deficiency of vitamin D are common health concern in our subjects and may be involved in the dysfunction of adipocytes and the development of AGA.

Maternal plasma vitamin D levels across pregnancy are not associated with neonatal birthweight: findings from an Australian cohort study of low-risk pregnant women

BACKGROUND

In utero environments can be highly influential in contributing to the development of offspring obesity. Specifically, vitamin D deficiency during pregnancy is associated with adverse maternal and child health outcomes, however its relationship with offspring obesity remains unclear. We assessed maternal vitamin D status across pregnancy, change in plasma vitamin D concentrations and associations with neonatal birthweight, macrosomia and large for gestational age.

METHODS

Women (n = 221) aged 18-40 years with singleton (low-risk) pregnancies, attending antenatal clinics at a tertiary-level maternity hospital were recruited at 10-20 weeks gestation. Medical history, maternal weight and blood samples at three antenatal clinic visits were assessed; early (15 ± 3 weeks), mid (27 ± 2 weeks) and late (36 ± 1 weeks) gestation. Maternal 25(OH)D was analysed from stored plasma samples via liquid chromatography-tandem mass spectrometry (LC/MS/MS). Neonatal growth parameters were collected at birth. Unadjusted and adjusted linear and logistic regression assessed associations of maternal vitamin D with birthweight, macrosomia and large for gestational age.

RESULTS

Mean plasma 25(OH)D increased from early (83.8 ± 22.6 nmol/L) to mid (96.5 ± 28.9 nmol/L) and late (100.8 ± 30.8 nmol/L) gestation. Overall 98% of women were taking vitamin D-containing supplements throughout their pregnancy. Prevalence of vitamin D deficiency (25(OH)D < 50 nmol/L) was 6.5%, 6.3% and 6.8% at early, mid and late pregnancy respectively. No statistically significant association was found between 25(OH)D or vitamin D deficiency at any timepoint with neonatal birthweight, macrosomia or large for gestational age.

CONCLUSIONS

Prevalence of vitamin D deficiency was low in this cohort of pregnant women and likely related to the high proportion of women taking vitamin D supplements during pregnancy. Maternal 25(OH)D did not impact offspring birth weight or birth size. Future studies in high-risk pregnant populations are needed to further assess maternal vitamin D status and factors in utero which promote early life obesity.

The role of vitamin D on redox regulation and cellular senescence

Vitamin D is considered an essential micronutrient for human health that is metabolized into a multifunctional secosteroid hormone. We can synthesize it in the skin through ultraviolet B (UVB) rays or acquire it from the diet. Its deficiency is a major global health problem that affects all ages and ethnic groups. Furthermore, dysregulation of vitamin D homeostasis has been associated with premature aging, driven by various cellular processes, including oxidative stress and cellular senescence. Various studies have shown that vitamin D can attenuate oxidative stress and delay cellular senescence, mainly by inducing the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and Klotho and improving mitochondrial homeostasis, proposing this vitamin as an excellent candidate for delaying aging. However, the mechanisms around these processes are not yet fully explored. Therefore, in this review, the effects of vitamin D on redox regulation and cellular senescence are discussed to propose new lines of research and clinical applications of vitamin D in the context of age-related diseases.

Serum Vitamin-D Levels And Severity Of Clinical Depression In Patients Of A Psychiatric Clinic in Pakistan

Vitamin D deficiency is often correlated with nervous system disorders like major depression, Parkinson’s disease and dementia. While much of the clinical literature suggests its association with clinical depression, very few studies have looked into the relationship between vitamin D levels and clinical depression severity. Objectives: To find out the association between vitamin D levels in patients suffering from different severities of clinical depression with the confounding socio-cultural factors of a third-world country i.e., Pakistan. Methods: The cross-sectional study was conducted in Lady Reading Hospital, Peshawar for five months with convenience sampling. Results: Overall, the study had 132 (36.57%) males and 229 (63.43%) females, and 236 diagnosed cases of Clinical Depression. In terms of Vitamin D levels, 242 (67.04%) had deficient, while 77 (21.33%) and 42 (11.63%) had insufficient and normal vitamin D levels, respectively. There was a statistically significant difference in the serum Vitamin D levels between at least two groups (F (3,232) = [38.64], p < 0.05). Conclusions: Vitamin D levels showed a dose-dependent, inverse relation with the severity of clinical depression in the Pakistani population

Autophagy in adipogenesis: Molecular mechanisms and regulation by bioactive compounds

White adipose tissue expands rapidly due to increased adipocyte number (hyperplasia) and size (hypertrophy), which results in obesity. Adipogenesis is a process of the formation of mature adipocytes from precursor cells. Additionally, obesity-related metabolic complications, such as fatty liver and insulin resistance, are linked to adipogenesis. On the contrary, autophagy is a catabolic process; essential to maintain cellular homeostasis via the degradation or recycling of unnecessary or damaged components. Importantly, autophagy dictates obesity and adipogenesis. Hence, a clear understanding of how autophagy regulates adipogenesis is crucial for drug development and the prevention and treatment of obesity and its associated disorders, such as type 2 diabetes, cardiovascular disease, and cancer. In this review, we highlighted recent findings regarding the crosstalk between adipogenesis and autophagy, as well as the molecules involved. Furthermore, the review discussed how bioactive compounds regulate adipogenesis by manipulating autophagy and underlying molecular mechanisms. Based on in vitro and animal studies, we summarized the effects of bioactive compounds on adipogenesis and autophagy. Hence, human studies are necessary to validate the effectiveness and optimal dosage of these bioactive compounds.

Association between anthropometric markers of adiposity, adipokines and vitamin D levels

Inverse association between serum levels of vitamin D and obesity has been pointed out in several studies. Our aim was to identify to the associations between vitamin D levels and a large panel of anthropometric markers and adipokines. Cross-sectional study including 6485 participants. Anthropometric markers included body mass index (BMI), % body fat, waist, waist-to-hip (WHR), waist-to-height (WHtR), conicity index, body roundness index (BRI) and a body shape index (ABSI). 55.7% of women and 60.1% of men presented with vitamin D deficiency. Vitamin D levels were negatively associated with most anthropometric markers, with correlation coefficients ranging between −0.017 (ABSI) and −0.192 (BMI) in women and between −0.026 (weight) and −0.130 (% body fat) in men. Vitamin D levels were inversely associated with leptin levels in both sexes and positively associated with adiponectin levels in women only. The likelihood of vitamin D deficiency increased with increasing adiposity levels, except for ABSI (women) and BMI (men). Total body fat, rather than localized or unevenly distributed body fat, is the adiposity marker most associated with decreased vitamin D levels. Monitoring vitamin D levels in people with overweight/obesity is essential.

Association of 25 (OH) Vitamin D and Leptin in Individuals with Insulin Resistance

Introduction

Asian-Indian individuals with diabetes have been shown to have low vitamin D levels. Whether this hypovitamonisis D is associated with hyperleptinaemia is unclear. Also, whether this association is different in those with and without insulin resistance has not been ascertained. The present study aimed to investigate the association of 25-hydroxy vitamin D [25(OH) vitamin D] and leptin in individuals with and without insulin resistance.

Methods

Ninety two individuals were recruited in two study groups (n = 46 each group). First group included individuals with insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR] ≥2.0). Second group included those without insulin resistance (HOMA-IR <2.0). Comparison of 25(OH) vitamin D, leptin, anthropometry, and biochemical parameters was done between two groups and correlations between 25(OH) vitamin D, leptin, and HOMA-IR were studied.

Results

Individuals with insulin resistance were of simiar age (39.6 ± 5.3 years) and body mass index (24.4 ± 3.2 kg/m2) as those without (39.5 ± 5.2 years and 23.6 ± 3.2 kg/m2). Individuals with insulin resistance showed significantly lower 25(OH) vitamin D (17.8 ± 7.1 vs. 22.3 ± 11.6 ng/mL, P = .03) and significantly higher leptin levels (16.9 ± 15.8 vs. 9.6 ± 9.3 ng/mL, P = .09) compared to those without. Significant negative correlation was observed between 25(OH) vitamin D and leptin levels overall (r = -0.3, P = .008). HOMA-IR showed significantly negative correlation with 25(OH) vitamin D levels in individuals with insulin resistance (r = -0.33, P = .027).

Conclusion

The present study found higher circulating leptin levels and lower 25(OH) vitamin D levels in individuals with insulin resistance. 25(OH) vitamin D levels were inversely associated with leptin levels particularly in women.

Vitamin D Supplementation and Its Relationship with Loss of Visceral Adiposity

PURPOSE

An inverse relationship between vitamin D (VD) nutritional status and obesity is frequent, and the distribution of body fat is an important aspect to assess the risks of obesity-related metabolic dysfunction. The purpose of the study was to evaluate the relationship between serum VD concentrations and body fat reduction after 12 months of bariatric surgery, using two different vitamin D3 (VD3) supplementation protocols.

MATERIAL AND METHODS

A randomized controlled trial consisted of 41 patients divided into G1 (800 IU/day) and G2 (1800 IU/day) according to the VD3 supplementation. At baseline (T0) and follow-up (T1), 25(OH)D, waist circumference (WC), visceral adiposity index (VAI), body adiposity index (BAI), and waist/height ratio (WHtR) were evaluated.

RESULTS

In T0, the mean of 25(OH)D was lower in G2 compared to that in G1 (22.6 vs 23.6 ng/mL; p = 0.000). At T1, it had a significant increase in G2 (32.1 vs 29.9 ng/mL; p = 0.000), with 60% sufficiency. A significant negative correlation was observed between VAI, BAI, and WHtR with 25(OH)D in G2 (r =  - 0.746, p = 0.024; r =  - 0.411, p = 0.036; r =  - 0.441, p = 0.032) after surgery. Higher mean changes from baseline of visceral fat loss, represented by VAI, were observed in G2 (176.2 ± 149.0-75.5 ± 55.0, p = 0.000).

CONCLUSION

Patients submitted to the 1800 IU/day protocol, 12 months after the surgical procedure, had a higher percentage of sufficient vitamin D levels compared to those submitted to the 800 IU/day protocol. Additionally, higher dose supplementation promoted a significant improvement in VAI.

Vitamin D and Visceral Obesity in Humans: What Should Clinicians Know?

The extraskeletal effect of vitamin D on adipose tissue biology and modulation in human obesity is of great interest and has been extensively investigated. Current evidence from preclinical and clinical studies in human adipose tissue suggests that the anti-inflammatory effects of vitamin D are evident and consistent, whereas the effects of vitamin D on adipocyte differentiation, adipogenesis, and energy metabolism and the effects of vitamin D supplementation on adipokine levels are inconclusive. Interventional studies related to medical and surgical weight loss in humans have shown small or no improvement in vitamin D status. Additionally, the benefit of vitamin D supplementation for the reduction in visceral adipose tissue has only been demonstrated in a few studies. Overall, the findings on the relationship between vitamin D and visceral adipose tissue in humans are still inconclusive. Further studies are required to confirm the beneficial effects of vitamin D on ameliorating adipose tissue dysfunction.

Vitamin D and Obesity/Adiposity—A Brief Overview of Recent Studies

Observational studies classically find an inverse relationship between human plasma 25-hydroxyvitamin D concentration and obesity. However, interventional and genetic studies have failed to provide clear conclusions on the causal effect of vitamin D on obesity/adiposity. Likewise, vitamin D supplementation in obese rodents has mostly failed to improve obesity parameters, whereas several lines of evidence in rodents and prospective studies in humans point to a preventive effect of vitamin D supplementation on the onset of obesity. Recent studies investigating the impact of maternal vitamin D deficiency in women and in rodent models on adipose tissue biology programming in offspring further support a preventive metabolically driven effect of vitamin D sufficiency. The aim of this review is to summarize the state of the knowledge on the relationship between vitamin D and obesity/adiposity in humans and in rodents and the impact of maternal vitamin D deficiency on the metabolic trajectory of the offspring.

Vitamin D Levels as an Important Predictor for Type 2 Diabetes Mellitus and Weight Regain Post-Sleeve Gastrectomy

Weight Loss Surgery (WLS), including sleeve-gastrectomy (SG), results in significant weight loss and improved metabolic health in severe obesity (BMI ≥ 35 kg/m2). Previous studies suggest post-operative health benefits are impacted by nutrient deficiencies, such as Vitamin D (25(OH)D) deficiency, while it is currently unknown whether nutrient levels may actually predict post-surgery outcomes. As such, this study investigated whether 25(OH)D levels could predict metabolic improvements in patients who underwent SG. Patients with severe obesity (n = 309; 75% female) undergoing SG participated in this ethics-approved, non-randomized retrospective cohort study. Anthropometry, clinical data, 25(OH)D levels and serum markers were collected at baseline, 6-, 12- and 18-months post-surgery. SG surgery resulted in significant improvements in metabolic health at 6- and 12-months post-surgery compared with baseline, as expected. Patients with higher baseline 25(OH)D had significantly lower HbA1c levels post-surgery (p < 0.01) and better post-surgical T2DM outcomes, including reduced weight regain (p < 0.05). Further analysis revealed that baseline 25(OH)D could predict HbA1c levels, weight regain and T2DM remission one-year post-surgery, accounting for 7.5% of HbA1c divergence (p < 0.01). These data highlight that higher circulating 25(OH)D levels are associated with significant metabolic health improvements post-surgery, notably, that such baseline levels are able to predict those who attain T2DM remission. This highlights the importance of 25(OH)D as a predictive biomarker of post-surgery benefits.

Lower Levels of Vitamin D Are Associated with an Increase in Insulin Resistance in Obese Brazilian Women

Adult women are more likely to be obese than men. Moreover, there is evidence that obesity is a risk factor for increased insulin resistance (IR) and hypovitaminosis D (VITD), conditions related to metabolic and endocrinologic disturbance. We performed a cross-sectional study with 103 women diagnosed with obesity, recruited between 2009 and 2013, in an obesity referral outpatient clinic in Bahia, Brazil. Laboratory and clinical characteristics were compared between the groups according to the degree of obesity (I, II and III), and levels of 25-hydroxyvitamin D [25(OH)D] were used to define the VITD status (insufficiency and no insufficiency). We calculated the homeostatic model assessment-IR (HOMA-IR) index to assess insulin resistance in the groups. Our analyses revealed that HOMA-IR values and VITD levels were inversely correlated. Furthermore, we observed a distinct expression profile of values of laboratory markers according to 25(OH)D levels. Negative correlations were found between HOMA-IR and body mass index (BMI) in VITD insufficient participants but not in those with the sufficiency. Furthermore, multivariate regression demonstrated independent associations between lower levels of 25(OH)D and increased values of HOMA-IR. These findings suggests that lower levels of VITD are strongly associated with the increased IR in obese women.

Vitamin D Status and Its Correlation With Anthropometric and Biochemical Indicators of Cardiometabolic Risk in Serbian Underground Coal Miners in 2016

The status of vitamin D in underground working coal miners and its association with their cardiometabolic health is rarely studied. This study aimed to examine vitamin D (VitD) status in Serbian underground coal miners and to correlate it with anthropometric and laboratory indicators of cardiometabolic risk. Nutritional data (food frequency questionnaire, FFQ, and two times repeated 24 h recall), anthropometric data (including segmental analysis by bio-impedance analyzer TANITA BC-545N), arterial tension, and biochemical and hematological data of 103 coal miners (aged 22-63 years) were correlated with their late summer (early September) serum 25 (OH)D levels (measured by HPLC). 68.9% of the studied coal miners were overweight/obese, and 48.5% had metabolic syndrome. Their mean VitD nutritional intakes were low: 5.3 ± 3.8 μg/day (FFQ) and 4.9 ± 8 μg/day (24 h recalls), but their mean serum 25 (OH)D levels were surprisingly high (143.7 ± 41.4 nmol/L). Only 2.9% of the coal miners had 25(OH)D levels lower than 75 nmol/L (indicating an insufficient/deficient status), while 63.2% had values above 125 nmol/L (upper optimal limit), and even 10.7% had values above 200 nmol/L. There were no statistical differences in 25 (OH)D levels in the coal miners with or without metabolic syndrome (or overweight/obesity). Interestingly, 25(OH)D levels had significant positive correlations with body mass index (BMI), fat mass (FM), fat mass percentage (FM%), limbs FM%, serum triglycerides, GGT, AST, ALT, and ALT/AST ratio, and had significant negative correlations with serum HDL-cholesterol and age. All these correlations were lost after corrections for age, FM, FM%, and legs FM%. In Serbian coal miners, high levels of early September VitD levels were observed, indicating sufficient non-working-hour sun exposure during the summer period. Furthermore, the unexpected positive correlations of VitD levels with anthropometric and biochemical parameters indicative of obesity, metabolic syndrome, and fatty liver disease were found. More research is needed on the VitD status of coal miners (particularly in the winter period) and its relationship with their cardiometabolic status.

Calcitriol Promotes Differentiation of Glioma Stem-Like Cells and Increases Their Susceptibility to Temozolomide

Simple Summary

Cancer cells with a stem-like phenotype that are thought to be highly tumorigenic are commonly described in glioblastoma, the most common primary adult brain cancer. This phenotype comprises high self-renewal capacity and resistance against chemotherapy and radiation therapy, thereby promoting tumor progression and disease relapse. Here, we show that calcitriol, the hormonally active form of the “sun hormone” vitamin D₃, effectively suppresses stemness properties in glioblastoma stem-like cells (GSCs), supporting the hypothesis that calcitriol sensitizes them to additional chemotherapy. Indeed, a physiological organotypic brain slice model was used to monitor tumor growth of GSCs, and the effectiveness of combined treatment with temozolomide, the current standard-of-care, and calcitriol was proven. These findings indicate that further research on applying calcitriol, a well-known and safe drug, as a potential adjuvant therapy for glioblastoma is both justified and necessary.

Abstract

Glioblastoma (GBM) is the most common and most aggressive primary brain tumor, with a very high rate of recurrence and a median survival of 15 months after diagnosis. Abundant evidence suggests that a certain sub-population of cancer cells harbors a stem-like phenotype and is likely responsible for disease recurrence, treatment resistance and potentially even for the infiltrative growth of GBM. GBM incidence has been negatively correlated with the serum levels of 25-hydroxy-vitamin D₃, while the low pH within tumors has been shown to promote the expression of the vitamin D₃-degrading enzyme 24-hydroxylase, encoded by the CYP24A1 gene. Therefore, we hypothesized that calcitriol can specifically target stem-like glioblastoma cells and induce their differentiation. Here, we show, using in vitro limiting dilution assays, quantitative real-time PCR, quantitative proteomics and ex vivo adult organotypic brain slice transplantation cultures, that therapeutic doses of calcitriol, the hormonally active form of vitamin D₃, reduce stemness to varying extents in a panel of investigated GSC lines, and that it effectively hinders tumor growth of responding GSCs ex vivo. We further show that calcitriol synergizes with Temozolomide ex vivo to completely eliminate some GSC tumors. These findings indicate that calcitriol carries potential as an adjuvant therapy for a subgroup of GBM patients and should be analyzed in more detail in follow-up studies.

Vitamin D in the Covid-19 era: a review with recommendations from a G.I.O.S.E.G. expert panel

Vitamin D (VITD) is a key hormone for bone health and has relevant extra-skeletal effects that might play a role in the prevention and treatment of COronaVIrus Disease 19 (COVID-19). Literature regarding this scenario is voluminous but controversial. Glucocorticoid Induced Osteoporosis Skeletal Endocrinology Group (G.I.O.S.E.G) has been present in the scientific debate about the use of VITD and has regularly interfaced national regulatory agencies to ensure appropriateness of its employment. Given the current pandemic and the questions on COVID-19 and VITD, G.I.O.S.E.G. appointed an expert panel to advise how to consider this issue best. The results of these deliberations are reported in the current recommendation paper.

Vitamin D Status and Its Influence on the Health of Preschool Children in Hangzhou

Objective: Vitamin D deficiency and insufficiency in children are global public health problems. However, few studies have focused on vitamin D status in healthy preschool children, especially in Asia. This study aimed to investigate vitamin D status and host-related factors in healthy preschool children in Hangzhou to analyze the impact of low vitamin D levels (<30 ng/mL) on health outcomes (obesity, early childhood caries, and respiratory tract infections).

Methods: A total of 1,510 healthy children aged 24–72 months from 15 kindergartens in Hangzhou were included. Data on the children's gender, age, body mass index (BMI), caries, and blood samples available for vitamin D analysis were collected from June to August 2018. A total of 325 children aged 36–48 months took part in a survey on the frequency of respiratory tract infections in the last year.

Results: The children's mean 25(OH)D level was 28.01 ± 7.29 ng/mL. A total of 11.4% of the children had vitamin D deficiency, and 52.6% had vitamin D insufficiency. Only 36.0% had vitamin D sufficiency. No significant difference was found by gender or BMI group. However, children in the obesity group had the highest prevalence of vitamin D deficiency and the lowest 25(OH)D levels. A significant negative correlation was found between the 25(OH)D level and child age (r = −0.144, p < 0.001). Regression analysis showed that the children’s 25(OH)D levels decreased by 0.17 ng/mL per month with age. In addition, children with low vitamin D levels might increase the risk of obesity and early childhood caries. Multiple linear regression indicated that the number of caries in children increased by 0.08 per 1-ng/mL decrease in the 25(OH)D level (β = −0.08, p < 0.001).

Conclusion: Vitamin D deficiency/insufficiency is a serious problem among healthy preschool children in Hangzhou. Public health policies or interventions should be implemented to ensure that preschool children have adequate vitamin D to reduce the risk of related diseases.