Causal relationship between obesity and vitamin D status: bi-directional Mendelian randomization analysis of multiple cohorts

Vitamin D supplementation and energy and metabolic homoeostasis in obese and overweight subjects: a protocol for a systematic review

INTRODUCTION

Obesity and vitamin D deficiency are major public health problems. According to the pathophysiological mechanism of obesity as well as the bidirectional relationship between obesity and vitamin D metabolism and storage, vitamin D supplementation in obese and overweight subjects could have beneficial effects on the energy and metabolic homoeostasis. This review will assess the efficacy of vitamin D supplementation on the energy and metabolic homoeostasis in overweight and obese subjects.

METHODS AND ANALYSIS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols, we retrieved the relevant literature from the following electronic bibliographic databases: MEDLINE/PubMed, EMBASE and the Cochrane Central Register of Controlled Trials, from inception to June 2021. A manual search of the reference lists of all the relevant research articles will be performed to identify additional studies. We will include randomised controlled trials (RCTs) published in English that examine the effects of vitamin D supplementation on energy and metabolic homoeostasis in overweight and obese subjects. RCTs with multiple vitamin D groups will also be included. Two reviewers will independently complete the article selection, data extraction and rating. The bias tool from the Cochrane Handbook for Systematic Reviews of Interventions was used to assess the methodological quality of the included studies. A narrative or quantitative synthesis will be performed based on the available data. The planned start and end dates for the study were 1 February 2021 and 1 March 2022.

ETHICS AND DISSEMINATION

Ethical approval will not be required for this review. The results of this review will be disseminated in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42021228981.

GeNuIne (gene-nutrient interactions) Collaboration: towards implementing multi-ethnic population-based nutrigenetic studies of vitamin B12 and D deficiencies and metabolic diseases

Gene-nutrient interactions (GeNuIne) collaboration, a large-scale collaborative project, has been initiated to investigate the impact of gene-nutrient interactions on cardiometabolic diseases using population-based studies from ethnically diverse populations. In this project, the relationship between deficiencies of vitamins B12 and D, and metabolic diseases was explored using a nutrigenetic approach. A genetic risk score (GRS) analysis was used to examine the combined effect of several genetic variations that have been shown to be associated with metabolic diseases and vitamin B12 and D deficiencies, respectively. In Sri Lankan, Indonesian and Brazilian populations, those carrying a high B12-GRS had an increased risk of metabolic diseases under the influence of dietary protein, fibre and carbohydrate intakes, respectively; however, in Asian Indians, genetically instrumented metabolic disease risk showed a significant association with low vitamin B12 status. With regards to nutrigenetic studies on vitamin D status, although high metabolic-GRS showed an interaction with dietary carbohydrate intake on vitamin D status, the study in Indonesian women demonstrated a vitamin D GRS-carbohydrate interaction on body fat percentage. In summary, these nutrigenetic studies from multiple ethnic groups have provided evidence for the influence of the dietary factors on the relationship between vitamin B12/D deficiency and metabolic outcomes. Furthermore, these studies highlight the existence of genetic heterogeneity in gene-diet interactions across ethnically diverse populations, which further implicates the significance of personalised dietary approaches for the prevention of these micronutrient deficiencies and metabolic diseases.

Improving vitamin D status in bariatric surgery subjects with monthly high-dose ergocalciferol

Background: Vitamin D insufficiency is common before and after bariatric surgery. Optimal supplementation to treat vitamin D insufficiency is not clearly defined. Objective: Determine if serum 25 (OH) D levels improve by the consumption of an additional monthly ergocalciferol supplement by subjects after bariatric surgery. Study design: Thirty-two subjects were randomly divided to receive an additional 100,000 IUs of ergocalciferol monthly after bariatric surgery (n=10) or standard level vitamin D supplement after bariatric surgery (n=22). Serum 25 (OH) D, calcium, and hemoglobin A1c levels were measured preoperatively and one year after bariatric surgery. Results: Mean changes in BMI at 1-year post-operation was -18.12±6.46 kg/m² in the control group versus -18.84±4.7 kg/m²; p=0.638 in the vitamin D group. One year after bariatric surgery, the mean changes from baseline in vitamin D levels were 2.69±9.4 and 12.4±17.0 ng/mL in control and intervention groups, respectively. The treated group showed a marginally higher mean increase in Vitamin D than the control group, p=0.059. Other mean changes at 1-year post-surgery that were not significantly different include calcium -0.264±0.45 and -0.21±0.509 mg/dl in control and intervention groups, respectively and Hgb A1c -1.0±1.21 and -0.95±0.071% in control and intervention groups, respectively. Conclusion: This study showed 100,000 IUs ergocalciferol once a month is a safe and effective treatment for vitamin D insufficiency in most patients having bariatric surgery.

Effect of Memantine Treatment and Combination with Vitamin D Supplementation on Body Composition in the APP/PS1 Mouse Model of Alzheimer's Disease Following Chronic Vitamin D Deficiency

BACKGROUND

Vitamin D deficiency and altered body composition are common in Alzheimer's disease (AD). Memantine with vitamin D supplementation can protect cortical axons against amyloid-β exposure and glutamate toxicity.

OBJECTIVE

To study the effects of vitamin D deprivation and subsequent treatment with memantine and vitamin D enrichment on whole-body composition using a mouse model of AD.

METHODS

Male APPswe/PS1dE9 mice were divided into four groups at 2.5 months of age: the control group (n = 14) was fed a standard diet throughout; the remaining mice were started on a vitamin D-deficient diet at month 6. The vitamin D-deficient group (n = 14) remained on the vitamin D-deficient diet for the rest of the study. Of the remaining two groups, one had memantine (n = 14), while the other had both memantine and 10 IU/g vitamin D (n = 14), added to their diet at month 9. Serum 25(OH)D levels measured at months 6, 9, 12, and 15 confirmed vitamin D levels were lower in mice on vitamin D-deficient diets and higher in the vitamin D-supplemented mice. Micro-computed tomography was performed at month 15 to determine whole-body composition.

RESULTS

In mice deprived of vitamin D, memantine increased bone mineral content (8.7% increase, p < 0.01) and absolute skeletal tissue mass (9.3% increase, p < 0.05) and volume (9.2% increase, p < 0.05) relative to controls. This was not observed when memantine treatment was combined with vitamin D enrichment.

CONCLUSION

Combination treatment of vitamin D and memantine had no negative effects on body composition. Future studies should clarify whether vitamin D status impacts the effects of memantine treatment on bone physiology in people with AD.

Potential impact of the steroid hormone, vitamin D, on the vasculature

The role of vitamin D in the cardiovascular system is complex because it regulates expression of genes involved in diverse metabolic processes. Although referred to as a vitamin, it is more accurately considered a steroid hormone, because it is produced endogenously in the presence of ultraviolet light. It occurs as a series of sequentially activated forms, here referred to as vitamin D-hormones. A little-known phenomenon, based on pre-clinical data, is that its biodistribution and potential effects on vascular disease likely depend on whether it is derived from diet or sunlight. Diet-derived vitamin D-hormones are carried in the blood, at least in part, in chylomicrons and lipoprotein particles, including low-density lipoprotein. Since low-density lipoprotein is known to accumulate in the artery wall and atherosclerotic plaque, diet-derived vitamin D-hormones may also collect there, and possibly promote the osteochondrogenic mineralization associated with plaque. Also, little known is the fact that the body stores vitamin D-hormones in adipose tissue with a half-life on the order of months, raising doubts about whether the use of the term "daily requirement" is appropriate. Cardiovascular effects of vitamin D-hormones are controversial, and risk appears to increase with both low and high blood levels. Since low serum vitamin D-hormone concentration is reportedly associated with increased cardiovascular and orthopedic risk, oral supplementation is widely used, often together with calcium supplements. However, meta-analyses show that oral vitamin D-hormone supplementation does not protect against cardiovascular events, findings that are also supported by a randomized controlled trial. These considerations suggest that prevalent recommendations for vitamin D-hormone supplementation for the purpose of cardiovascular protection should be carefully reconsidered.

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.

Transforming growth factor beta 1 (TGFβ1) plasmatic levels and haplotype structures in obesity: a role for TGFβ1 in steatosis development

BACKGROUND

Obesity is considered a chronic inflammatory disease and transforming growth factor beta 1 (TGFβ1) might exert important roles in disease pathogenesis regulating adipocyte differentiation and immune-inflammatory environment. However, the role of this cytokine as a biomarker in obesity is poorly addressed. Therefore, the present study aimed to evaluate the impact of TGFB1 polymorphisms and TGFβ1 plasmatic levels in obesity METHODS AND RESULTS: TGFB1 promoter region polymorphisms (rs1800468, G-800A and rs1800469, C-509 T) were evaluated in 75 obese patients and 45 eutrophic patients through PCR-RFLP and plasmatic TGFβ1 was quantified through ELISA from 37 of the obese patients, and correlations with clinical and biochemical parameters were tested. Despite no association was found between TGFB1 polymorphisms and obesity susceptibility, several correlations with clinical data were noted. Among others, AC haplotype negatively correlated with plasmatic TGFβ1, while plasmatic TGFβ1 negatively correlated with C-reactive protein and positively correlated with liver abnormalities on ultrasound and, specifically, with steatosis presence and degree. Conversely, GT haplotype, which associates with higher TGFβ1 production, was also positively correlated with the same parameters of liver abnormalities. Further, plasmatic vitamin D negatively correlated with TGFβ1, while positively correlated with AC haplotype.

CONCLUSION

Overall, the results indicate that TGFβ1 might exert important roles in obesity pathophysiology and correlate with biochemical and clinical parameters both at systemic protein as well as at genetic level. Importantly, the consistent positive correlation at both levels with steatosis might suggest this cytokine as a biomarker for this hepatic abnormality in obese patients.

Are There Ethnic Differences in Micronutrient Deficiencies in Preoperative Bariatric Patients? A Systematic Review and Meta-analysis

The purpose of this systematic review was to determine if in patients presenting for bariatric surgery, patients of different ethnicities, have different micronutrient deficiencies preoperatively. Databases searched were PubMed, Embase, MEDLINE and Cochrane Library. A meta-analysis of prevalence of vitamin D insufficiency (<20ng/ml) was carried out using a random effects model. Twenty-eight articles were included assessing preoperative micronutrient status across different ethnic groups. The most common micronutrient assessed was vitamin D, and the most assessed ethnicity was Caucasian. African Americans had the greatest prevalence of vitamin D insufficiency when compared to other ethnicities with a pooled prevalence and 95% confidence interval of 0.80 [0.74; 0.85]. There was a significant difference in vitamin D insufficiency when compared across ethnicities (p <0.01).

Nutritional parameters and outcomes in patients admitted to intensive care with COVID-19: a retrospective single-centre service evaluation

COVID-19 is an inflammatory syndrome caused by novel coronavirus SARS-CoV-2. Symptoms range from mild infection to severe acute respiratory distress syndrome (ARDS) requiring ventilation and intensive care. At the time of data collection, UK cases were around 300 000 with a fatality rate of 13% necessitating over 10 000 critical care admissions; now there have been over 4 million cases. Nutrition is important to immune function and influences metabolic risk factors such as obesity and glycaemic control, as well as recovery from acute illnesses. Poor nutritional status is associated with worse outcomes in ARDS and viral infections, yet limited research has assessed pre-morbid nutritional status and outcomes in patients critically unwell with COVID-19.

OBJECTIVES

Investigate the effect of body mass index (BMI), glycaemic control and vitamin D status on outcomes in adult patients with COVID-19 admitted to an intensive care unit (ICU).

METHODS

Retrospective review of all patients admitted to a central London ICU between March and May 2020 with confirmed COVID-19. Electronic patient records data were analysed for patient demographics; comorbidities; admission BMI; and serum vitamin D, zinc, selenium and haemoglobin A1c (HbA1c) concentrations. Serum vitamin D and HbA1c were measured on admission, or within 1 month of admission to ICU. Primary outcome of interest was mortality. Secondary outcomes included time intubated, ICU stay duration and ICU-related morbidity.

RESULTS

Seventy-two patients; 54 (75%) men, mean age 57.1 (±9.8) years, were included. Overall, mortality was 24 (33%). No significant association with mortality was observed across BMI categories. In the survival arm admission, HbA1c (mmol/mol) was lower, 50.2 vs 60.8, but this was not statistically significant. Vitamin D status did not significantly associate with mortality (p=0.131). However, 32% of patients with low vitamin D (<25 IU/L) died, compared with 13% of patients with vitamin D levels >26 IU/L. Serum zinc and selenium, and vitamin B12 and folate levels were measured in 46% and 26% of patients, respectively.

DISCUSSION/CONCLUSION

Increased adiposity and deranged glucose homeostasis may potentially increase risk of COVID-19 infection and severity, possibly relating to impaired lung and metabolic function, increased proinflammatory and prothrombotic mechanisms. Vitamin D deficiency may also associate with poorer outcomes and mortality, supporting a possible role of vitamin D in immune function specific to pulmonary inflammation and COVID-19 pathophysiology. There are plausible associations between raised BMI, glycaemic control, vitamin D status and poor prognosis, as seen in wider studies; however, in this service evaluation audit during the first wave of the pandemic in the UK, with a limited data set available for this analysis, the associations did not reach statistical significance. Further research is needed into specific nutritional markers influencing critical care admissions with COVID-19.

The supplementary effects of omega-3 fatty acid alone and in a combination with vitamin D3 on serum leptin levels: A randomized clinical trial on men and women with vitamin D deficiency

Purpose: This randomized clinical trial (RCT) was designed to assess the effect of VD3, n-3FA, and their combination on serum leptin levels in people with vitamin D deficiency (VDD).

Subjects and methods: One hundred and forty six participants, were randomly assigned into four groups supplemented with the dose of 50,000 IU VD3 taken weekly (D), 300 mg n-3FA taken daily (Om), and their combination (D+Om) or control (C) for eight weeks. Fasting baseline and follow-up (10 weeks; 8 weeks supplementation plus washout period of 2 weeks) of serum 25 hydroxyvitamin D (25OHD), leptin, glucose, triglycerides (TG), parathyroid hormone (PTH), calcium, and phosphorus were assayed. A paired T-test was used to assess the changes in serum leptin levels over of the follow-up period.

Results: Significant increase in follow-up serum leptin (10.62 ± 7.18 to 14.42 ± 8.29 ng/mL, P = 0.002) and TG (154 ± 84.4 to 200.1 ± 79, P = 0.015) levels were observed in n-3-FA supplemented group. Combination therapy (VD3 plus n-3 FA) significantly increased serum 25OHD (13.49 ± 4.64 to 37.09 ± 11.13 ng/mL, P &lt; 0.001), TG levels (114.3 ± 57.3 to 139.1 ± 60.7 mg/mL, P = 0.007) and insignificantly serum leptin (6.74 ± 4.87 to 8.01 ± 6.77 ng/mL, P = 0.269).

Conclusion: Our study referred that notable elevation in leptin and TG levels might be linked to leptin resistance. However, further RCTs are required to clarify possible consequences resulted from the extensive administration of n-3FA supplements and their combinations with high doses of VD3 supplements on humans’ health.

Vitamin D in the time of the coronavirus (COVID-19) pandemic - a clinical review from a public health and public mental health perspective

Individuals with serious mental disorders (SMD) may have a higher risk of vitamin D (VIT-D) deficiency. They also experience higher mortality because of coronavirus disease 2019 (COVID-19) infection. Therefore, we have conducted a comprehensive review to examine the significance of VIT-D for public health and public mental health during the ongoing COVID-19 pandemic. This review had three specific aims, from a global perspective to (a) create a profile of VIT-D and review the epidemiology of VIT-D deficiency, (b) explore VIT-D deficiency as risk factor for SMD and COVID-19 infections and (c) examine the effectiveness of VIT-D supplementation for both conditions. We found that, in terms of SMD, the evidence from laboratory and observational studies points towards some association between VIT-D deficiency and depression or schizophrenia. Mendelian randomisation studies, however, suggest no, or reverse, causality. The evidence from intervention studies is conflicting. Concerning COVID-19 infection, on proof of principle, VIT-D could provide a plausible defence against the infection itself and against an adverse clinical course. But data from observational studies and the first preliminary intervention studies remain conflicting, with stronger evidence that VIT-D may mitigate the clinical course of COVID-19 infection rather than the risk of infection in the first place. From a public health and public mental health point of view, based on the currently limited knowledge, for individuals with SMD, the benefits of VIT-D optimisation through supplementation seem to outweigh the risks. VIT-D supplementation, however, should not substitute for vaccination or medical care for COVID-19 infection.

The Role of Diet in Bone and Mineral Metabolism and Secondary Hyperparathyroidism

Bone disorders are a common complication of chronic kidney disease (CKD), obesity and gut malabsorption. Secondary hyperparathyroidism (SHPT) is defined as an appropriate increase in parathyroid hormone (PTH) secretion, driven by either reduced serum calcium or increased phosphate concentrations, due to an underlying condition. The available evidence on the effects of dietary advice on secondary hyperparathyroidism confirms the benefit of a diet characterized by decreased phosphate intake, avoiding low calcium and vitamin D consumption (recommended intakes 1000-1200 mg/day and 400-800 UI/day, respectively). In addition, low protein intake in CKD patients is associated with a better control of SHPT risk factors, although its strength in avoiding hyperphosphatemia and the resulting outcomes are debated, mostly for dialyzed patients. Ultimately, a consensus on the effect of dietary acid loads in the prevention of SHPT is still lacking. In conclusion, a reasonable approach for reducing the risk for secondary hyperparathyroidism is to individualize dietary manipulation based on existing risk factors and concomitant medical conditions. More studies are needed to evaluate long-term outcomes of a balanced diet on the management and prevention of secondary hyperparathyroidism in at-risk patients at.

The effects of Vitamin D3 supplementation on Spermatogram and endocrine factors in asthenozoospermia infertile men: a randomized, triple blind, placebo-controlled clinical trial

OBJECTIVE

Evaluate the effects of vitamin D3 (VD3) on sperm parameters and endocrine markers in infertile men with asthenozoospermia.

MATERIALS AND METHODS

This randomized, triple-masking, placebo-controlled clinical trial conducted on 86 asthenozoospermia infertile men with serum 25 hydroxy vitamin D3 (25(OH)VD3) < 30 ng/ml in the infertility clinic of Ahvaz Jahad daneshgahi, Iran. Patients were randomly allocated to groups A and B, who received daily 4000 IU VD3 and matching placebo respectively for 3 months. Demographic data, dietary intake, physical activity, sun exposure, anthropometric indices, serum 25(OH)VD3, luteinizing hormone (LH), follicle-stimulating hormone (FSH), total testosterone (T), estradiol (E2),, sex hormone-binding globulin (SHBG), free androgen index (FAI = T/SHBG. 100), T/LH and T/E2 ratios, prolactin (PRO), parathyroid hormone (PTH), osteocalcin (OCN), phosphorus and sperm parameters were assessed.

RESULTS

Three months VD3 supplementation with 4000 IU/day had no significant effects body weight, body mass index (BMI), waist circumference (WC), body fat (BF), serum, OCN, LH, FSH, T, E2, SHBG, PRO, T/E2 ratio, FAI, semen volume, sperm count and normal sperm morphology. It increases serum 25(OH)VD3, PTH and phosphorus and seminal and serum calcium, T/LH ratio and total and progressive sperm motility and decreased significantly compared to the baseline and placebo group.

CONCLUSION

VD3 supplementation may affect sperm motility in men with asthenozoospermia and serum 25(OH)VD3 < 30 ng/ml.

TRIAL REGISTRATION

Iran Clinical Trials Registry, ID: IRCT20151128025274N4, registered on 28 March 2018, URL of trial registry record: https://www.irct.ir/trial/29983.

Vitamin D and coronavirus disease 2019 (COVID-19): rapid evidence review

BACKGROUND

The rapid global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), has re-ignited interest in the possible role of vitamin D in modulation of host responses to respiratory pathogens. Indeed, vitamin D supplementation has been proposed as a potential preventative or therapeutic strategy. Recommendations for any intervention, particularly in the context of a potentially fatal pandemic infection, should be strictly based on clinically informed appraisal of the evidence base. In this narrative review, we examine current evidence relating to vitamin D and COVID-19 and consider the most appropriate practical recommendations.

OBSERVATIONS

Although there are a growing number of studies investigating the links between vitamin D and COVID-19, they are mostly small and observational with high risk of bias, residual confounding, and reverse causality. Extrapolation of molecular actions of 1,25(OH)₂-vitamin D to an effect of increased 25(OH)-vitamin D as a result of vitamin D supplementation is generally unfounded, as is the automatic conclusion of causal mechanisms from observational studies linking low 25(OH)-vitamin D to incident disease. Efficacy is ideally demonstrated in the context of adequately powered randomised intervention studies, although such approaches may not always be feasible.

CONCLUSIONS

At present, evidence to support vitamin D supplementation for the prevention or treatment of COVID-19 is inconclusive. In the absence of any further compelling data, adherence to existing national guidance on vitamin D supplementation to prevent vitamin D deficiency, predicated principally on maintaining musculoskeletal health, appears appropriate.

Prior loss of body mass index, low body mass index, and central obesity independently contribute to higher rates of fractures in elderly women and men

We aimed to comprehensively evaluate the association of body composition with fracture risk using longitudinal data from a Swedish cohort of 44,366 women and men (mean age of 70 years) and a subcohort of 5022 women. We estimated hazard ratios (HRs) of fracture for baseline body mass index (BMI), BMI change during the prior 12 and 18 years, baseline waist-to-height ratio, total and regional distribution of fat and lean mass, with and without areal bone mineral density (BMD) adjustment. During follow-up (median 8.7 years), 7290 individuals sustained a fracture, including 4279 fragility fractures, of which 1813 were hip fractures. Higher baseline BMI and prior gain in BMI were inversely associated with all types of fracture. Lower fracture rate with higher baseline BMI was seen within every category of prior BMI change, whereas higher prior BMI gain conferred a lower rate of fracture within those with normal baseline BMI. Each standard deviation (SD) higher baseline waist-to-height ratio, after adjustment for BMI, was associated with higher rates of hip fracture in both women and men (HR 1.12; 95% CI, 1.05-1.19). In the subcohort (median follow-up 10 years), higher baseline fat mass index (FMI) and appendicular lean mass index (LMI) showed fracture-protective effects. After BMD adjustment, higher baseline BMI, total LMI, FMI, and higher prior BMI gain were associated with higher fracture rate. Baseline fat distribution also was associated with fracture rate; a 1-SD higher android to gynoid fat mass ratio in prior BMI gainers was associated with BMD-adjusted HRs of 1.16 (95% CI, 1.05-1.28) for any fracture and 1.48 (95% CI, 1.16-1.89) for hip fracture. This pattern was not observed among prior BMI losers. These findings indicate that for optimal fracture prevention, low baseline BMI, prior BMI loss and high baseline central obesity should be avoided in both women and men. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Association of vitamin D deficiency and insulin resistance with breast cancer in premenopausal Algerian women: A cross-sectional study

BACKGROUND

Low 25(OH)D levels are mainly related to breast cancer (BC) risk in postmenopausal women, while the impact of insulin resistance (IR) on BC prognosis is controversial.

OBJECTIVE

Considering the high prevalence of BC in younger Algerian women, this cross-sectional study analyzed whether vitamin D status and IR are biomarkers for breast tumor status in premenopausal women.

METHODS

In 96 women (mean age, 40.96±0.65years) newly diagnosed with BC, tumor status was determined immunohistochemically, classified by molecular subtype, then correlated with body-mass index, total plasma 25(OH)D, insulin and glucose levels and HOMA-IR, using chi², Student t, Spearman and ANOVA tests and multivariate logistic regression.

RESULTS

66 of the 98 patients (68.75%) showed vitamin D deficiency (9.74ng/mL). Overweight and obese patients with HOMA-IR >2.5, positive for HER2 and with high Ki-67 index had the most severe vitamin D deficiency. There was a significant association between vitamin D deficiency, high Ki-67 index (OR, 14.55; 95% CI, 3.43-82.59; p=0.00078) and IR (OR, 4.99; 95% CI, 1.27-24.47; p=0.03), and between IR and HER2-positivity (OR, 3.23; 95% CI, 1.05-10.56; p=0.04).

CONCLUSIONS

Vitamin D deficiency and IR are potential biomarkers for poorer prognosis in BC patients, independently of and/or synergically with high Ki-67 index and HER2-positivity in premenopausal overweight or obese women. The potential relationship of vitamin D receptor gene expression with breast cancer survival in Algerian patients will be investigated in a large cohort.

[Nutrition and mental health - how findings from genetic studies can support the identification of dietary effects]

Nutrition and mental health - how findings from genetic studies can support the identification of dietary effects Abstract. Introduction: Numerous studies indicate that dietary interventions could be an important approach to the prevention and treatment of mental disorders. However, conventional nutritional epidemiological approaches (e. g., observational studies and randomized controlled trials, RCTs) have specific limitations to consider when interpreting the results. This article examines whether genetic studies could help to establish a link between diet and the prevention of mental disorders. Furthermore, it examines whether it is possible to draw conclusions about causal relationships. Methods: This narrative review describes various approaches of genetic cross-phenotype studies and presents examples of their applications in nutritional psychiatry. In addition, it discusses specific requirements as well as the strengths and limitations of the respective approaches. Results: To date, in the context of nutritional psychiatry, genetic correlation analyses, look-up analyses, and Mendelian randomization (MR) studies have been used for genetic crossphenotype analyses. Genetic correlation and look-up analyses provide initial evidence of possible overlap between specific mental disorders and metabolic pathways or specific nutrients. MR studies are used for detailed analyses that aim to identify causal relationships. However, MR is based on specific assumptions that must be met and considered when results are interpreted. Conclusion: Genetic cross-phenotype analyses are a useful amendment to conventional nutritional epidemiological research. In particular, positive results from MR studies provide an important fundament for identifying and developing suitable dietary interventions, which in turn increases the chance of success upon testing in subsequent RCTs. Accordingly, genetic cross-phenotype analyses are important instruments for increasing the efficiency in nutritional psychiatric research.

Daily intake of yogurt drink fortified either with vitamin D alone or in combination with added calcium causes a thyroid-independent increase of resting metabolic rate in adults with type 2 diabetes: a randomized double blind clinical trial

We investigated the effect of daily intake of yogurt drink fortified with either vitamin D alone or with added calcium on resting metabolic rate (RMR), thyroid hormones and homeostatic model assessment for insulin resistance (HOMA-IR) in subjects with type 2 diabetes (T2D). A total of 75 adult subjects with T2D were randomly assigned to one of the three groups to receive either D-fortified yogurt drink (DY; 1000 IU vitamin D/d), Ca-D-fortified yogurt drink (CDY; 1000 IU vitamin D plus 500 mg calcium), or plain yogurt drink (PY) for 12 weeks. All assessments were done at the baseline and after the intervention. The concentrations of anti-thyroid peroxidase antibody (anti-TPO-Ab), intact parathyroid hormone (iPTH) and thyroid stimulating hormone (TSH) had significant decline compared with baseline values only in CDY group. The mean RMR increased in both DY and CDY groups (p<0.001 for both). Also, changes of serum concentrations of 25(OH)D (B= 2.96, 95%CI= 1.3- 4.6, p=0.001) and iPTH (B= -2.41, 95%CI= -4.5- -0.31, p=0.025) remained significant predictors of RMR changes even after adjustment for changes of serum concentrations of TSH (B= -18.2, 95%CI= -61.7- 25.2, p=0.406). Daily intake of vitamin D together with calcium at physiological doses has attenuating effect on anti-TPO-Ab and TSH. Also, vitamin D with or without added calcium causes a significant thyroid-independent increase in RMR in euthyroid subjects with T2D. Registered at clinicaltrials.gov as NCT01229891. Novelty: Daily intake of vitamin D with calcium at physiological doses has attenuating effect on anti-TPO-Ab and TSH. Vitamin D with or without added calcium causes a thyroid-independent increase in RMR in euthyroid subjects with T2D.

Vitamin D and Obesity: Current Evidence and Controversies

PURPOSE OF REVIEW

Evidence from observational studies suggests that obesity is associated with low vitamin D. As both obesity and hypovitaminosis D present an alarmingly increased prevalence worldwide, there is an intense research interest to clarify all aspects of this association. This review summarizes current evidence from meta-analyses investigating vitamin D status in obesity, including the effects of weight loss and bariatric surgery on vitamin D status and the outcomes of vitamin D supplementation on body weight. We also discuss potential pathophysiologic mechanisms and important controversies.

RECENT FINDINGS

Data from meta-analyses consistently support an inverse association of vitamin D levels with body weight. However, the impact of weight loss on improving vitamin D status is small, while studies on the supplementation with vitamin D after bariatric surgery have shown conflicting results regarding vitamin D status. Moreover, interventional studies do not support a beneficial effect of vitamin D supplementation on body weight. These findings warrant a cautious interpretation due to important methodological limitations and confounding factors, such as high heterogeneity of studies, variable methods of determination of vitamin D and definition of deficiency/insufficiency, use of various adiposity measures and definitions of obesity, and inadequate adjustment for confounding variables influencing vitamin D levels. The underlying pathogenetic mechanisms associating low vitamin D in obesity include volumetric dilution, sequestration into adipose tissue, limited sunlight exposure, and decreased vitamin D synthesis in the adipose tissue and liver. Experimental studies have demonstrated that low vitamin D may be implicated in adipose tissue differentiation and growth leading to obesity either by regulation of gene expression or through modulation of parathyroid hormone, calcium, and leptin. Obesity is associated with low vitamin D status but weight loss has little effect on improving this; vitamin D supplementation is also not associated with weight loss. Evidence regarding vitamin D status after bariatric surgery is contradicting. The link between vitamin D and obesity remains controversial due to important limitations and confounding of studies. More research is needed to clarify the complex interplay between vitamin D and adiposity.

Association between serum 25-hydroxyvitamin D concentrations and obesity in one-year-old Chinese infants

Recent studies suggested that vitamin D is linked with obesity, but evidence in infants is scarce. Therefore, we aimed to make an exploration in infants. A total of 414 infants at one year old who visited Maternity and Child Health Care Hospital of Wuxi in China were recruited. Finger-stick blood sampling was conducted in all the subjects, and serum 25-hydroxyvitamin D [25(OH)D] concentrations were measured. Maternal characteristics during pregnancy and infantile information were collected by questionnaires or extracting from medical records. Multivariable linear models were performed to assess the relationship between 25(OH)D and body mass index (BMI), while multivariable logistic regression models were used to examine the association between 25(OH)D and obesity. Among the 414 infants, 69 (16.67%) and 81 (19.57%) infants were defined as obesity and vitamin D deficiency [25(OH)D < 50 nmol/L], respectively. The mean (SD) of 25(OH)D concentration was 68.05 (19.05) in infants without obesity, which was significantly higher than that of obese infants [60.36(18.49), p = .002]. Inverse linear relationships were observed between 25(OH)D level and BMI (β = -0.017, p = .004) as well as BMI Z-score (β = -0.010, p = .004). Furthermore, vitamin D deficiency was associated with an increased risk of obesity of infants (adjusted odds ratio = 2.74, 95% confidence interval = 1.20-6.25, with 25(OH)D ≥ 75 nmol/L as a reference). The results showed that serum 25(OH)D concentrations were significantly lower in infants with obesity, suggesting vitamin D deficiency may be an independent risk factor for obesity among one-year-old Chinese infants.

Is There a Benefit of Vitamin D Supplementation in Deficient Children and Adolescents Suffering from Obesity? A Meta-Analysis

This systematic review/meta-analysis aims to highlight the effect of vitamin D supplementation in deficient children suffering from obesity. Published clinical studies on vitamin D supplementation in obese children and adolescents with vitamin D deficiency were identified through a comprehensive MEDLINE/PubMed search (from July 1966 to November 2017). Outcomes intended after vitamin D supplementation were improvements in vitamin D status, BMI alterations and appetite changes. The inclusion criteria were children aged 2 to 18 years of both sexes in clinical trials that specified the oral and/or intramuscular dose of vitamin D supplementation. Ten studies were retrieved, but only 6 were relevant. First, supplemented obese children and adolescents were compared to non-obese controls; thereafter, supplemented obese children and adolescents were compared to matching obese peers given placebo. Pooled risks from the 2 studies that evaluated the number of obese and non-obese children and adolescents who improved upon vitamin D supplementation revealed that obesity poses a risk for not benefiting from the vitamin D supplementation regardless of the dose and the duration of supplementation. Pooled results from the 6 retrieved studies that compared supplemented obese children and adolescents to matching non-obese or obese peers given placebo revealed significantly lower vitamin D levels in obese participants than in non-obese peers. Vitamin D levels are significantly lower in obese children and adolescents with obesity, posing a risk for not benefiting from vitamin D supplementation regardless of the dose and duration of supplementation.

Controlling Nutritional Status (CONUT) Score and Micronutrient Deficiency in Bariatric Patients: Midterm Outcomes of Roux-en-Y Gastric Bypass Versus One Anastomosis Gastric Bypass/Mini Gastric Bypass

BACKGROUND

Two of the most common bariatric procedures performed worldwide are Roux-en-Y gastric bypass (RYGB) and one anastomosis gastric bypass (OAGB). Comparative data regarding nutritional status are lacking and no previous study focus on malnutrition according to a validated score.

METHODS

Retrospective data from a single institution were reviewed. Anthropometric variables and nutritional data were assessed. The primary aim was to analyze and compare the nutritional status before and 3 years after RYGB vs OAGB using the controlling nutritional status (CONUT) score. The incidence of micronutrient deficiency and the remission of comorbidities in each group were defined as secondary outcomes.

RESULTS

Fifty-seven patients in each arm were enrolled. A 3-year mild malnutrition (CONUT score 2-3) was found in 38% and 37.05% in the RYGB and OAGB groups, respectively (p > 0.05). In terms of percentage of total weight loss (%TWL) and percentage of adjustable weight loss (%AWL), no differences were found between OAGB and RYGB groups. OAGB and RYGB patients had similar vitamin deficiencies. Anemia, hypoproteinemia, hypoalbuminemia, and hypocalcemia were comparable between groups. At 3-year follow-up, total protein and albumin values were similar between arms while prealbumin deficit was more frequent after OAGB than after RYGB. The rate of type 2 diabetes (87.5% in OAGB and 92% in RYGB), arterial hypertension (51.6% in OAGB and 58.3% in RYGB), and dyslipidemia (69.7% in OAGB and 78.6% in RYGB) remission was not significantly different between the two groups.

CONCLUSIONS

Postoperative CONUT score, micronutrient deficiency, comorbidity remission, and improvement of anthropometric parameters 3 years postoperatively were comparable between RYGB and OAGB groups.

Genetically predicted serum vitamin D and COVID-19: a Mendelian randomisation study

OBJECTIVES

To investigate causality of the association of serum vitamin D with the risk and severity of COVID-19 infection.

DESIGN

Two-sample Mendelian randomisation study.

SETTING

Summary data from genome-wide analyses in the population-based UK Biobank and SUNLIGHT Consortium, applied to meta-analysed results of genome-wide analyses in the COVID-19 Host Genetics Initiative.

PARTICIPANTS

17 965 COVID-19 cases including 11 085 laboratory or physician-confirmed cases, 7885 hospitalised cases and 4336 severe respiratory cases, and 1 370 547 controls, primarily of European ancestry.

EXPOSURES

Genetically predicted variation in serum vitamin D status, instrumented by genome-wide significant single nucleotide polymorphisms (SNPs) associated with serum vitamin D or risk of vitamin D deficiency/insufficiency.

MAIN OUTCOME MEASURES

Susceptibility to and severity of COVID-19 infection, including severe respiratory infection and hospitalisation.

RESULTS

Mendelian randomisation analysis, sufficiently powered to detect effects comparable to those seen in observational studies, provided little to no evidence for an effect of genetically predicted serum vitamin D on susceptibility to or severity of COVID-19 infection. Using SNPs in loci related to vitamin D metabolism as genetic instruments for serum vitamin D concentrations, the OR per SD higher serum vitamin D was 1.04 (95% CI 0.92 to 1.18) for any COVID-19 infection versus population controls, 1.05 (0.84 to 1.31) for hospitalised COVID-19 versus population controls, 0.96 (0.64 to 1.43) for severe respiratory COVID-19 versus population controls, 1.15 (0.99 to 1.35) for COVID-19 positive versus COVID-19 negative and 1.44 (0.75 to 2.78) for hospitalised COVID-19 versus non-hospitalised COVID-19. Results were similar in analyses using SNPs with genome-wide significant associations with serum vitamin D (ie, including SNPs in loci with no known relationship to vitamin D metabolism) and in analyses using SNPs with genome-wide significant associations with risk of vitamin D deficiency or insufficiency.

CONCLUSIONS

These findings suggest that genetically predicted differences in long-term vitamin D nutritional status do not causally affect susceptibility to and severity of COVID-19 infection, and that associations observed in previous studies may have been driven by confounding. These results do not exclude the possibility of low-magnitude causal effects or causal effects of acute responses to therapeutic doses of vitamin D.

Cholecalciferol Supplementation Does Not Prevent the Development of Metabolic Syndrome or Enhance the Beneficial Effects of Omega-3 Fatty Acids in Obese Mice

BACKGROUND

Cholecalciferol (D3) may improve inflammation, and thus provide protection from cardiometabolic diseases (CMD), although controversy remains. Omega-3 fatty acids (ω-3FA) may also prevent the development of CMD, but the combined effects of ω-3FA and D3 are not fully understood.

OBJECTIVES

We determined the chronic independent and combined effects of D3 and ω-3FA on body weight, glucose homeostasis, and markers of inflammation in obese mice.

METHODS

We gave 8-week-old male C57BL/6J mice, which had been fed a high-fat, high-sucrose (HF) diet (65.5% kcal fat, 19.8% kcal carbohydrate, and 14% kcal protein) for 12 weeks, either a standard D3 dose (+SD3; 1400 IU D3/kg diet) or a high D3 dose (+HD3; 15,000 IU D3/kg diet). We fed 1 +SD3 group and 1 +HD3 group with 4.36% (w/w) fish oil (+ω-3FA; 44% eicosapentaenoic acid, 25% docosahexaenoic acid), and fed the other 2 groups with corn oil [+omega-6 fatty acids (ω-6FA)]. A fifth group was fed a low-fat (LF; 15.5% kcal) diet. LF and HF+ω-6+SD3 differences were tested by a Student's t-test and HF treatment differences were tested by a 2-way ANOVA.

RESULTS

D3 supplementation in the +HD3 groups did not significantly increase plasma total 25-hydroxyvitamin D and 25-hydroxyvitamin D3 [25(OH)D3] versus the +SD3 groups, but it increased 3-epi-25-hydroxyvitamin D3 levels by 3.4 ng/mL in the HF+ω-6+HD3 group and 4.0 ng/mL in the HF+ω-3+HD3 group, representing 30% and 70%, respectively, of the total 25(OH)D3 increase. Energy expenditure increased in those mice fed diets +ω-3FA, by 3.9% in the HF+ω-3+SD3 group and 7.4% in the HF+ω-3+HD3 group, but it did not translate into lower body weight. The glucose tolerance curves of the HF+ω-3+SD3 and HF+ω-3+HD3 groups were improved by 11% and 17%, respectively, as compared to the respective +ω-6FA groups. D3 supplementation, within the ω-3FA groups, altered the gut microbiota by increasing the abundance of S24-7 and Lachnospiraceae taxa compared to the standard dose, while within the ω-6FA groups, D3 supplementation did not modulate specific taxa.

CONCLUSIONS

Overall, D3 supplementation does not prevent CMD or enhance the beneficial effects of ω-3FA in vitamin D-sufficient obese mice.

Association between Cardiometabolic risk factor and responsiveness to vitamin D supplementation: a new approach using artificial neural network analysis

BACKGROUND

There are increasing data highlighting the effectiveness of vitamin D supplementation in the treatment of vitamin D deficiency. But individuals vary in their responsiveness to vitamin D supplementation. In this study, the association between several cardiometabolic risk factors and the magnitude of response to vitamin D supplementation (change in vitamin D level) was investigated using a novel artificial neural networks (ANNs) approach.

METHODS

Six hundred eight participants aged between 12 to 19 years old were recruited to this prospective interventional study. Nine vitamin D capsules containing 50,000 IU vitamin D/weekly were given to all participants over the 9 week period. The change in serum 25(OH) D level was calculated as the difference between post-supplementation and basal levels. Suitable ANNs model were selected between different algorithms in the hidden and output layers and different numbers of neurons in the hidden layer. The major determinants for predicting the response to vitamin D supplementation were identified.

RESULTS

The sigmoid in both the hidden and output layers with 4 hidden neurons had acceptable sensitivity, specificity and accuracy, assessed as the area under the ROC curve, was determined in our study. Baseline serum vitamin D (30.4%), waist to hip ratio (10.5%), BMI (10.5%), systolic blood pressure (8%), heart rate (6.4%), and waist circumference (6.1%) were the most important factors in predicting the response to serum vitamin D levels.

CONCLUSION

We provide the first attempt to relate anthropometric specific recommendations to attain serum vitamin D targets. With the exception of cardiometabolic risk factors, the relative importance of other factors and the mechanisms by which these factors may affect the response requires further analysis in future studies (Trial registration: IRCT201509047117N7; 2015-11-25; Retrospectively registered).

Effect of low-fat dairy products fortified with 1500IU nano encapsulated vitamin D3 on cardiometabolic indicators in adults with abdominal obesity: a total blinded randomized controlled trial

BACKGROUND & AIMS

Vitamin D deficiency is widespread worldwide. In this study, we aimed to evaluate the effect of a nano encapsulated form of vitamin D used for fortifying low-fat dairy products (milk and yogurt) on anthropometric indices, glycemic status, and lipid profile in subjects with abdominal obesity.

METHODS

In a totally (quadruple) blinded, randomized, and parallel-controlled trial, 306 individuals with abdominal obesity were randomly allocated to one of four groups: fortified low-fat yogurt (FY, 1500 IU nano encapsulated vitamin D₃ per 150 g/d), non-fortified low-fat yogurt (nFY), fortified low-fat milk (FM, 1500 IU nano encapsulated vitamin D₃ per 200 g/d), non-fortified low-fat milk (nFM), for 10 weeks (nFM and nFY, were considered as the control groups). Anthropometric and biochemical parameters were measured at baseline and after a ten-week trial in Mashhad, Iran.

RESULTS

After the ten-week intervention, we found a significant increase in serum concentration of 25(OH)D in both the FM and FY groups compared to the respective control groups (19.10 ± 5.69 ng/mL and 20.88 ± 5.76 ng/mL respectively, p < .001). We observed a significant reduction in weight to hip ratio (p = .04) and a significant improvement in triglyceride (p < .001) and HDL-C (p = .01) only in FM group compared to nFM group. Also, we found a significant reduction in fasting serum insulin (p < .001), and a significant improvement of HOMA-IR (p < .001) and QUICKI (p < .001) in both intervention groups compared to their placebos.

CONCLUSIONS

An intake of fortified dairy products containing nano-encapsulated vitamin D₃ was associated with an improvement in some measures of anthropometric indices, glucose homeostasis, and lipid profiles, particularly in individuals receiving fortified milk. Hence, along with other benefits, fortification of dairy products with vitamin D may be an effective approach to improve some cardiometabolic indicators, such as insulin resistance.

TRIAL REGISTRATION NUMBER

IRCT20101130005280N27.

Low serum vitamin D concentrations are associated with obese but not lean NAFLD: a cross-sectional study

BACKGROUND

A low serum vitamin D concentration has been reported to be associated with an increased risk of non-alcoholic fatty liver disease (NAFLD); however, whether lean or obese individuals show a similar association between vitamin D and NAFLD remains speculative. This study aimed to explore the relationship between serum vitamin D concentration and NAFLD in lean and obese Chinese adults.

METHODS

This cross-sectional study included 2538 participants (1360 men and 1178 women) who underwent health checkups at the First Affiliated Hospital, Zhejiang University School of Medicine in 2019. NAFLD was diagnosed by liver ultrasound excluding other causes. The association of serum vitamin D concentration with NAFLD was analyzed in lean and obese participants.

RESULTS

The overall prevalence of NAFLD was 33.61% (13.10% in lean and 53.32% in obese) in this study population. The serum vitamin D levels of obese NAFLD patients were lower than those of obese NAFLD-free controls. However, the serum vitamin D levels of lean NAFLD patients were comparable to those of lean NAFLD-free controls. Serum vitamin D level was negatively correlated with the prevalence of NAFLD in obese but not lean participants. Serum vitamin D level was independently associated with the risk of NAFLD in obese participants, with an adjusted odds ratio (95% CI) of 0.987 (0.981-0.993). However, serum vitamin D level was not related to the risk of NAFLD in lean participants.

CONCLUSIONS

A low serum vitamin D level is associated with NAFLD in obese but not lean participants.

Mismatch: a comparative study of vitamin D status in British-Bangladeshi migrants

Background and objectives

Low levels of vitamin D among dark-skinned migrants to northern latitudes and increased risks for associated pathologies illustrate an evolutionary mismatch between an environment of high ultraviolet (UV) radiation to which such migrants are adapted and the low UV environment to which they migrate. Recently, low levels of vitamin D have also been associated with higher risks for contracting COVID-19. South Asians in the UK have higher risk for low vitamin D levels. In this study, we assessed vitamin D status of British-Bangladeshi migrants compared with white British residents and Bangladeshis still living in Bangladesh (‘sedentees’).

Methodology

The cross-sectional study compared serum vitamin D levels among 149 women aged 35–59, comprising British-Bangladeshi migrants (n = 50), white British neighbors (n = 54) and Bangladeshi sedentees (n = 45). Analyses comprised multivariate models to assess serum levels of 25-hydroxyvitamin D (25(OH)D), and associations with anthropometric, lifestyle, health and migration factors.

Results

Vitamin D levels in Bangladeshi migrants were very low: mean 25(OH)D = 32.2 nmol/L ± 13.0, with 29% of migrants classified as deficient (<25 nmol/L) and 94% deficient or insufficient (≤50 nmol/L). Mean levels of vitamin D were significantly lower among British-Bangladeshis compared with Bangladeshi sedentees (50.9 nmol/L ± 13.3, P < 0.001) and were also lower than in white British women (55.3 nmol/L ± 20.9). Lower levels of vitamin D were associated with increased body mass index and low iron status.

Conclusions and implications

We conclude that lower exposure to sunlight in the UK reduces vitamin D levels in Bangladeshi migrants. Recommending supplements could prevent potentially adverse health outcomes associated with vitamin D deficiency.

Lay Summary

Vitamin D deficiency is one example of mismatch between an evolved trait and novel environments. Here we compare vitamin D status of dark-skinned British-Bangladeshi migrants in the UK to Bangladeshis in Bangladesh and white British individuals. Migrants had lower levels of vitamin D and are at risk for associated pathologies.

Osteosarcopenic adiposity syndrome update and the role of associated minerals and vitamins

The objectives are to present an updated synopsis on osteosarcopenic adiposity (OSA) syndrome and evaluate the roles of selected micronutrients in its prevention and management. OSA refers to the concurrent deterioration of bone (osteopenia/osteoporosis), muscle (sarcopenia) and adipose tissue expansion. It portrays the most advanced stage in a continuum of body composition disorders. Although OSA has been widely studied involving the populations of different backgrounds, its prevalence is hard to collate because different methodologies and criteria were used for its diagnosis. Another critical health aspect is the presence of low-grade chronic inflammation (LGCI) which contributes to OSA and vice versa. Nutrition is important in the prevention and management of both OSA and LGCI. Although micronutrients act in numerous metabolic and physiological processes, their roles here are presented in relation to OSA (and its components) and LGCI in general and relevant to the COVID-19 pandemic. These include calcium, magnesium, phosphorus, potassium, sodium and vitamins D and K; their interactions, physiological ratios and synergism/antagonism are discussed as well. In conclusion, calcium, magnesium and vitamin D have a profound impact on OSA and its components, and the latter two also on LGCI. Potassium and vitamin K are vital in bone, muscle functioning and possibly adipose tissue modification. Both, but particularly vitamin D, surfaced as important modulators of immune system with application in COVID-19 infections. While both phosphorus and sodium have important roles in bone, muscle and can impact adiposity, due to their abundance in food, their intake should be curbed to prevent possible damaging effects.

Application of the Instrumental Inequalities to a Mendelian Randomization Study With Multiple Proposed Instruments

Supplemental Digital Content is available in the text.

Investigators often support the validity of Mendelian randomization (MR) studies, an instrumental variable approach proposing genetic variants as instruments, via. subject matter knowledge. However, the instrumental variable model implies certain inequalities, offering an empirical method of falsifying (but not verifying) the underlying assumptions. Although these inequalities are said to detect only extreme assumption violations in practice, to our knowledge they have not been used in settings with multiple proposed instruments.

Role of Vitamin D in the Metabolic Syndrome

The prevalence of hypovitaminosis D has risen in developed countries over the past few years in association with lifestyle changes and an increase in unhealthy habits. Vitamin D deficiency has been implicated in various diseases, including metabolic syndrome (MetS), which is clinically defined by a set of metabolic and vascular disorders. The objective of this study was to review scientific evidence on the relationship between MetS and vitamin D deficiency to support the development of prevention strategies and health education programs. An inverse relationship has been reported between plasma vitamin D concentrations and the features that define MetS, i.e., elevated serum concentrations of glucose, total cholesterol, low-density lipoproteins, triglycerides, glycosylated hemoglobin, and a high body mass index. Numerous studies have described the benefits of vitamin D supplementation to improve outcomes in individuals with MetS. Interventions to maintain optimal vitamin D concentrations are proposed as a preventive strategy against MetS.

Obesity-induced Vitamin D Deficiency Contributes to Lung Fibrosis and Airway Hyperresponsiveness

Vitamin D (VitD) has pleiotropic effects. VitD deficiency is closely involved with obesity and may contribute to the development of lung fibrosis and aggravation of airway hyperresponsiveness (AHR). We evaluated the causal relationship between VitD deficiency and the lung pathologies associated with obesity. In vivo effects of VitD supplementation were analyzed using high-fat diet (HFD)-induced obese mice and TGF-β1 (transforming growth factor-β1) triple transgenic mice. Effects of VitD supplementation were also evaluated in both BEAS-2B and primary lung cells from the transgenic mice. Obese mice had decreased 25-OH VitD and VitD receptor expressions with increases of insulin resistance, renin and angiotensin-2 system (RAS) activity, and leptin. In addition, lung pathologies such as a modest increase in macrophages, enhanced TGF-β1, IL-1β, and IL-6 expression, lung fibrosis, and AHR were found. VitD supplementation to HFD-induced obese mice recovered these findings. TGF-β1-overexpressing transgenic mice enhanced macrophages in BAL fluid, lung expression of RAS, epithelial-mesenchymal transition markers, AHR, and lung fibrosis. VitD supplementation also attenuated these findings in addition to the attenuation of the expressions of TGF-β1, and phosphorylated Smad-2/3 in lung. Supplementing in vitro-stimulated BEAS-2B and primary lung cells with VitD inhibited TGF-β1 expression, supporting the suppressive effect of VitD for TGF-β1 expression. These results suggest that obesity leads to VitD deficiency and worsens insulin resistance while enhancing the expression of leptin, RAS, TGF-β1, and proinflammatory cytokines. These changes may contribute to the development of lung fibrosis and AHR. VitD supplementation rescues these changes and may have therapeutic potential for asthma with obesity.

Obesity in young children and its relationship with diagnosis of asthma, vitamin D deficiency, iron deficiency, specific allergies and flat-footedness: A systematic review and meta-analysis

There is evidence that a number of medical conditions and co-morbidities are associated with obesity in young children. This review explored whether there is evidence of associations with other conditions or co-morbidities. Observational studies of young children (mean age < 10 years) were identified using electronic searches of five databases (MEDLINE, Embase, CINAHL, AMED and SPORTDiscus). Of 27 028 studies screened, 41 (comprising 44 comparisons) met the inclusion criteria. These studies provided data on five distinct diseases/conditions: asthma (n = 16), vitamin D deficiency (n = 10), iron deficiency (n = 10), allergies (n = 4) and flat-footedness (n = 4). Thirty-two studies were appropriate for meta-analysis using random-effects models, and revealed obesity was significantly associated with having asthma (OR 1.5, 95% CI 1.3-1.7), vitamin D deficiency (OR 1.9, 95% CI 1.4-2.5) and iron deficiency (OR 2.1, 95% CI 1.4-3.2). Heterogeneity (I2 ) ranged from 57% to 61%. Narrative synthesis was conducted for all studies. There was no evidence of a consistent association between obesity in young children and eczema, dermatitis or rhinitis due to the low number of studies. However, there was an association with flat-footedness. These results have implications for health policy and practice and families. Further research leading to a greater understanding of the associations identified in this review is suggested.

Study of Cellular Senescence and Vitamin D Deficiency in Nonalcoholic Fatty Liver Disease and The Potential Protective Effect of Vitamin D Supplementation

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a pathological process characterized by excessive hepatic fatty deposition with possible involvement of vitamin D deficiency and cellular senescence. The aim of this study is to investigate the pathophysiologic role of vitamin D deficiency and cellular senescence in NAFLD development. Moreover, it aims to investigate the potential protective role of vitamin D supplementation.

METHODS

This is an experimental Case/Control study. Forty-five male albino rats were enrolled in this study. Animals were divided into four groups: negative and positive control groups (10 for each group), a model of NAFLD (11) and vitamin D-treated NAFLD groups (14). At the end of the experiment, all rats were subjected to the following investigation; biochemical estimation of serum 25 hydroxycholecalciferol, senescence marker protein-30 (SMP-30), lipid profile and calculation of homeostatic model of insulin resistance (HOMA-IR).

RESULTS

NAFLD group shows a significant increase in glucose, insulin levels, and HOMA- IR compared with both normal controls. This finding indicates the intimate association between insulin resistance and NAFLD pathogenesis. Moreover, it was found that NAFLD group shows a significant decrease in SMP-30 level compared with normal controls. While vitamin D-treated NAFLD group shows significant increased SMP-30 and decrease in HOMA-IR in comparison with nontreated NAFLD group.

CONCLUSION

Vitamin D deficiency and increased cellular senescence are key features of NAFLD. Vitamin D supplementation could play a protective role, which needs further investigation including clinical human study.

Unlocking the causal link of metabolically different adiposity subtypes with brain volumes and the risks of dementia and stroke: A Mendelian randomization study

To establish causal evidence for the association of adiposity-related metabolic abnormalities with brain volumes, and the risks of dementia and stroke, we applied 1- and 2-sample Mendelian randomization (MR) analyses using up to 336,309 UK Biobank participants. We used 3 classes of genetic instruments, which all increase body mass index but are associated with different metabolic profiles (unfavorable, neutral and favorable). We validated the instruments using anthropometric and cardio-metabolic traits. Both metabolically unfavorable and metabolically neutral adiposity associated with lower gray matter volume (GMV, -9.28 cm³, -12.90 to -5.66 and -12.02 cm³, -20.07 to -3.97, respectively). Metabolically favorable adiposity was tentatively associated with a higher GMV (16.21 cm³, -0.21 to 32.68). No causal evidence was seen for white matter and hippocampal volume, and volume of white matter hyperintensities, or with the risks of dementia and stroke (all p > 0.60). These findings suggest that obesity-related metabolic abnormalities may contribute to GMV atrophy, warranting further studies.

The relative contributions of obesity, vitamin D, leptin, and adiponectin to multiple sclerosis risk: A Mendelian randomization mediation analysis

BACKGROUND

Obesity is associated with increased risk of multiple sclerosis (MS); however, the underlying mechanisms remain unclear.

OBJECTIVE

To determine the extent to which decreased vitamin D bioavailability and altered levels of adiponectin and leptin mediate the association between obesity and MS.

METHODS

We performed Mendelian randomization (MR) analyses to estimate the effects on MS of body mass index (BMI), 25-hydroxyvitamin D (25OHD), adiponectin, and leptin levels in a cohort of 14,802 MS cases and 26,703 controls. We then estimated the proportion of the effect of obesity on MS explained by these potential mediators.

RESULTS

Genetic predisposition to higher BMI was associated with increased MS risk (odds ratio (OR) = 1.33 per standard deviation (SD), 95% confidence interval (CI) = 1.09-1.63), while higher 25OHD levels reduced odds of MS (OR = 0.72 per SD, 95% CI = 0.60-0.87). In contrast, we observed no effect of adiponectin or leptin. In MR mediation analysis, 5.2% of the association between BMI and MS was attributed to obesity lowering 25OHD levels (95% CI = 0.3%-31.0%).

CONCLUSIONS

This study found that a minority of the increased risk of MS conferred by obesity is mediated by lowered vitamin D levels, while leptin and adiponectin had no effect. Consequently, vitamin D supplementation would only modestly reverse the effect of obesity on MS.

Low sun exposure habits is associated with a dose-dependent increased risk of hypertension: a report from the large MISS cohort

In prospective observational cohort studies, increasing sun exposure habits have been associated with reduced risk of cardiovascular mortality. Our aim was to assess possible observational mechanisms for this phenomenon. A written questionnaire was answered by 23,593 women in the year 2000 regarding risk factors for melanoma, including factors of possible interest for hypertension, such as detailed sun exposure habits, hypertension, marital status, education, smoking, alcohol consumption, BMI, exercise, and chronic high stress. Hypertension was measured by the proxy "use of hypertension medication" 2005-2007, and high stress by "need of anti-depressive medication". Sun exposure habits was assessed by the number of `yes' to the following questions; Do you sunbath during summer?, During winter vacation?, Do you travel south to sunbath?, Or do you use sun bed? Women answering 'yes' on one or two questions had moderate and those answering 'yes' on three or four as having greatest sun exposure. The main outcome was the risk of hypertension by sun exposure habits adjusted for confounding. As compared to those women with the greatest sun exposure, women with low and moderate sun exposure were at 41% and 15% higher odds of hypertension (OR 1.41, 95% CI 1.3‒1.6, p < 0.001 and OR 1.15, 95% CI 1.1‒1.2, p < 0.001), respectively. There was a strong age-related increased risk of hypertension. Other risk factors for hypertension were lack of exercise (OR 1.36), a non-fair phenotype (OR 1.08), chronic high stress level (OR 1.8), and lack of university education (OR 1.3). We conclude that in our observational design sun exposure was associated with a dose-dependent reduced risk of hypertension, which might partly explain the fewer deaths of cardiovascular disease with increasing sun exposure.

Mendelian randomization provides no evidence for a causal role in the bidirectional relationship between depression and multiple sclerosis

BACKGROUND

Major depressive disorder (MDD) is common in multiple sclerosis (MS) and its incidence rises before MS diagnosis. However, the causality and direction of this association remain unclear.

OBJECTIVE

The objective is to investigate the bidirectional relationship between MS and MDD using Mendelian randomization (MR).

METHODS

We selected genetic instruments associated with risk of MDD (n = 660,937 cases; 1,453,489 controls) and MS (n = 47,429 cases; 68,374 controls). Using two-sample MR, we examined putative causal effects in either direction, with sensitivity analyses to assess pleiotropy. Also, we adjusted for body mass index (BMI) in multivariable MR.

RESULTS

We found no effect of genetic liability to MDD on the odds of MS (OR = 1.07/doubling in odds, 95% CI = 0.90-1.28). Similarly, our findings did not support a causal effect of genetic liability to MS on MDD (OR = 1.00/doubling in odds, 95% CI = 0.99-1.01). Despite heterogeneity, sensitivity analyses indicated that bias from pleiotropy was unlikely. Conversely, genetic predisposition toward higher BMI increased the odds of MS (OR = 1.34/SD increase, 95% CI = 1.09-1.65) and MDD (OR = 1.08, 95% CI = 1.01-1.15).

CONCLUSION

This study does not support a causal association between MDD genetic liability and MS susceptibility, and vice versa. Genetic evidence suggesting commonality of obesity to both conditions may partly explain the increased incidence of depression pre-MS diagnosis.

Interaction between Vitamin D-Related Genetic Risk Score and Carbohydrate Intake on Body Fat Composition: A Study in Southeast Asian Minangkabau Women

Metabolic diseases have been shown to be associated with low vitamin D status; however, the findings have been inconsistent. Hence, the objective of our study was to investigate the relationship between vitamin D status and metabolic disease-related traits in healthy Southeast Asian women and examine whether this relationship was modified by dietary factors using a nutrigenetic study. The study included 110 Minangkabau women (age: 25–60 years) from Padang, Indonesia. Genetic risk scores (GRS) were constructed based on five vitamin D-related single nucleotide polymorphisms (SNPs) (vitamin D-GRS) and ten metabolic disease-associated SNPs (metabolic-GRS). The metabolic-GRS was significantly associated with lower 25-hydroxyvitamin D (25(OH)D) concentrations (p = 0.009) and higher body mass index (BMI) (p = 0.016). Even though the vitamin D-GRS had no effect on metabolic traits (p > 0.12), an interaction was observed between the vitamin D-GRS and carbohydrate intake (g) on body fat percentage (BFP) (p_interaction = 0.049), where those individuals who consumed a high carbohydrate diet (mean ± SD: 319 g/d ± 46) and carried >2 vitamin D-lowering risk alleles had significantly higher BFP (p = 0.016). In summary, we have replicated the association of metabolic-GRS with higher BMI and lower 25(OH)D concentrations and identified a novel interaction between vitamin D-GRS and carbohydrate intake on body fat composition.

Investigating the effects of genetic risk of schizophrenia on behavioural traits

To characterise the trait-effects of increased genetic risk for schizophrenia, and highlight potential risk mediators, we test the association between schizophrenia polygenic risk scores (PRSs) and 529 behavioural traits (personality, psychological, lifestyle, nutritional) in the UK Biobank. Our primary analysis is performed on individuals aged 38–71 with no history of schizophrenia or related disorders, allowing us to report the effects of schizophrenia genetic risk in the sub-clinical general population. Higher schizophrenia PRSs were associated with a range of traits, including lower verbal-numerical reasoning (P = 6 × 10^–61), higher nervous feelings (P = 1 × 10⁻⁴⁶) and higher self-reported risk-taking (P = 3 × 10⁻³⁸). We follow-up the risk-taking association, hypothesising that the association may be due to a genetic propensity for risk-taking leading to greater migration, urbanicity or drug-taking — reported environmental risk factors for schizophrenia, and all positively associated with risk-taking in these data. Next, to identify potential disorder or medication effects, we compare the PRS–trait associations in the general population to the trait values in 599 medicated and non-medicated individuals diagnosed with schizophrenia in the biobank. This analysis highlights, for example, levels of BMI, physical activity and risk-taking in cases in the opposite directions than expected from the PRS–trait associations in the general population. Our analyses offer simple yet potentially revealing insights into the possible causes of observed trait–disorder associations, which can complement approaches such as Mendelian Randomisation. While we urge caution in causal interpretations in PRS cross-trait studies that are highly powered to detect weak horizontal pleiotropy or population structure, we propose that well-designed polygenic score analyses have the potential to highlight modifiable risk factors that lie on the path between genetic risk and disorder.

Does vitamin D deficiency increase the risk of obesity in adults and the elderly? A systematic review of prospective cohort studies

OBJECTIVES

Epidemiological studies indicate an association between vitamin D deficiency and obesity. However, there is no consistent evidence of the direction or causal relationship between these conditions. Thus, we analysed the longitudinal relationship between vitamin D deficiency and obesity/adiposity in different age groups.

STUDY DESIGN

This study was a systematic review with PROSPERO registry (CRD42016047523).

METHODS

Electronic searches were undertaken in Lilacs, Medline, Science Direct, Scopus and Web of Science databases until April 2020. For each study, we collected the frequency of vitamin D deficiency and obesity.

RESULTS

In total, 5071 articles were identified and 8 were ultimately included in this systematic review. Five cohort studies involved adults, two of which recorded a positive association between vitamin D deficiency and obesity. The other three studies found a borderline or null association between vitamin D deficiency and obesity. Three studies investigated the elderly population; two of these recorded an association between vitamin D and greater adiposity, and one study recorded that 25-hydroxyvitamin D levels ≥30 ng/ml were associated with less weight gain in the follow-up.

CONCLUSIONS

This review reports that the majority of studies included show that vitamin D deficiency can contribute to the occurrence of obesity in adults and the elderly. It is recommended that prospective studies are conducted, with varying age groups and weather conditions, designed to test the longitudinal relationship between vitamin D deficiency and obesity outcomes.

The causal role of circulating vitamin D concentrations in human complex traits and diseases: a large-scale Mendelian randomization study

Vitamin D has been associated with a variety of human complex traits and diseases in observational studies, but a causal relationship remains unclear. To examine a putative causal effect of vitamin D across phenotypic domains and disease categories, we conducted Mendelian randomization (MR) analyses using genetic instruments associated with circulating 25-hydroxyvitamin D [25(OH)D] concentrations. We leveraged genome-wide significant 25(OH)D-associated SNPs (N = 138) from a meta-analysis combining a vitamin D GWAS conducted in 401,460 white British UK Biobank (UKBB) participants and an independent vitamin D GWAS including 42,274 samples of European ancestry, and examined 190 large-scale health-related GWAS spanning a broad spectrum of complex traits, diseases and biomarkers. We applied multiple MR methods to estimate the causal effect of vitamin D while testing and controlling for potential biases from horizontal pleiotropy. Consistent with previous findings, genetically predicted increased 25(OH)D levels significantly decreased the risk of multiple sclerosis (OR = 0.824; 95% CI 0.689-0.986). The protective effect estimate was consistent across different MR methods and four different multiple sclerosis GWAS with varying sample sizes and genotyping platforms. On the contrary, we found limited evidence in support of a causal effect of 25(OH)D on anthropometric traits, obesity, cognitive function, sleep behavior, breast and prostate cancer, and autoimmune, cardiovascular, metabolic, neurological and psychiatric traits and diseases, and blood biomarkers. Our results may inform ongoing and future randomized clinical trials of vitamin D supplementation.

Obesity, oxidative DNA damage and vitamin D as predictors of genomic instability in children and adolescents

BACKGROUND/OBJECTIVES

Epidemiological evidence indicates obesity in childhood and adolescence to be an independent risk factor for cancer and premature mortality in adulthood. Pathological implications from excess adiposity may begin early in life. Obesity is concurrent with a state of chronic inflammation, a well-known aetiological factor for DNA damage. In addition, obesity has been associated with micro-nutritional deficiencies. Vitamin D has attracted attention for its anti-inflammatory properties and role in genomic integrity and stability. The aim of this study was to determine a novel approach for predicting genomic instability via the combined assessment of adiposity, DNA damage, systemic inflammation, and vitamin D status.

SUBJECTS/METHODS

We carried out a cross-sectional study with 132 participants, aged 10-18, recruited from schools and paediatric obesity clinics in London. Anthropometric assessments included BMI Z-score, waist and hip circumference, and body fat percentage via bioelectrical impedance. Inflammation and vitamin D levels in saliva were assessed by enzyme-linked immunosorbent assay. Oxidative DNA damage was determined via quantification of 8-hydroxy-2'-deoxyguanosine in urine. Exfoliated cells from the oral cavity were scored for genomic instability via the buccal cytome assay.

RESULTS

As expected, comparisons between participants with obesity and normal range BMI showed significant differences in anthropometric measures (p < 0.001). Significant differences were also observed in some measures of genomic instability (p < 0.001). When examining relationships between variables for all participants, markers of adiposity positively correlated with acquired oxidative DNA damage (p < 0.01) and genomic instability (p < 0.001), and negatively correlated with vitamin D (p < 0.01). Multiple regression analyses identified obesity (p < 0.001), vitamin D (p < 0.001), and oxidative DNA damage (p < 0.05) as the three significant predictors of genomic instability.

CONCLUSIONS

Obesity, oxidative DNA damage, and vitamin D deficiency are significant predictors of genomic instability. Non-invasive biomonitoring and predictive modelling of genomic instability in young patients with obesity may contribute to the prioritisation and severity of clinical intervention measures.

Association Between Secondary Hyperparathyroidism and Body Composition in Pediatric Patients With Moderate and Advanced Chronic Kidney Disease

Objective: This single center cross-sectional study aims to investigate the association between secondary hyperparathyroidism and body composition in pediatric patients with moderate (stage 3) and advanced (stage 4-5) chronic kidney disease (CKD). Methods: 61 patients (median age: 13.4 years) were included. Body composition indices, including lean tissue index (LTI) and fat tissue index (FTI), were measured using multi-frequency bio-impedance spectroscopy. Muscle wasting was defined as LTI adjusted to height-age (HA) z-score < -1.65 SD and high adiposity as FTI z-score > 1.65 SD. Serum mineral metabolism parameters, including serum intact parathormone (iPTH), calcium, phosphorus and 25-hydroxyvitamin D, as well as serum leptin were measured in each patient. In advanced CKD patients, the mean values of serum mineral laboratory parameters of the 6 months prior to body composition assessment were recorded, and alfacalcidol index, defined as weekly alfacalcidol dose (mcg/week) per pg/ml of iPTH × 1,000, was calculated. Results: In moderate CKD (31 patients), high iPTH (>90 ng/ml) was observed in 10 (32.3%) patients and was associated with higher FTI z-score (p = 0.022). Moreover, serum iPTH was negatively correlated to LTI HA z-score (rs = -0.486, p = 0.006), and positively correlated to serum leptin levels (rs = 0.369, p = 0.041). The positive correlation between FTI z-score and iPTH (rs = 0.393, p = 0.039) lost significance after adjustment for serum leptin. iPTH was positively associated with high adiposity (12 patients, 38.7%) after adjustment for the other mineral metabolism parameters (OR 1.023, 95% CI 1.002-1.045, p = 0.028). In advanced CKD (30 patients), no significant correlation was observed between iPTH and body composition indices and serum leptin levels. Eleven (36.7%) patients with muscle wasting presented lower alfacalcidol index (p = 0.017). Alfacalcidol index ≤ 24 was strongly associated with muscle wasting after adjustment for CKD stage and other mineral metabolism parameters (OR 7.226, 95% CI 1.150-45.384, p = 0.035). Conclusion: Secondary hyperparathyroidism is associated with high adiposity in moderate but not in advanced CKD, with leptin acting as a potential contributive factor. In advanced CKD, targeting higher alfacalcidol weekly dose per each unit of serum PTH seems beneficial for preventing muscle wasting.

Cortisol and Phosphate Homeostasis: Cushing's Syndrome Is Associated With Reversible Hypophosphatemia

OBJECTIVES

The influence of hypercortisolism on phosphate homeostasis is relatively unknown. A few previous studies have reported on patients with Cushing's syndrome (CS) with hypophosphatemia in whom serum phosphate normalized after initiation of treatment for CS. We aimed to investigate the prevalence of hypophosphatemia in CS, the association between the degree of hypercortisolism and serum phosphate and the change in serum phosphate after remission of CS. We compared the prevalence of hypophosphatemia in CS with the prevalence in the population-based Rotterdam Study (RS).

METHODS

Patients diagnosed with CS and treated at the Department of Endocrinology of Erasmus MC in the period of 2002-2020 were included and data was collected on age at diagnosis, sex, serum phosphate, calcium and potassium levels, kidney function and BMI. Using multivariate linear regression, we analyzed the association between 24h urinary free cortisol excretion (UFC) and serum phosphate. Changes in serum phosphate and covariates were tested with a repeated measurement ANOVA, using mean levels of laboratory values for the periods before remission, and 0-14 days and 15-180 days after remission.

RESULTS

Hypophosphatemia before treatment was present in 16% of the 99 CS patients with data on serum phosphate, 24h UFC and covariates. In comparison, the prevalence of hypophosphatemia in RS was 2.0-4.2%. Linear regression showed a negative association between the level of UFC and serum phosphate at diagnosis, which remained significant after adjusting for covariates [β -0.002 (95%CI -0.004; -0.0004), p=0.021]. A subset of 24 patients had additional phosphate measurements at 0-14 days and 15-180 days after remission. In this subgroup, serum phosphate significantly increased from 1.03 ± 0.17 mmol/L prior to remission to 1.22 ± 0.25 mmol/L 15-180 days after remission (p = 0.008). BMI decreased after remission [-1.1 kg/m², (95%CI -2.09 to -0.07), p=0.037]. Other covariates did not show an equivalent change over time.

CONCLUSION

In this retrospective study, we found that 16% of patients with CS had hypophosphatemia. Moreover, serum phosphate was related to the level of cortisoluria and increased after remission of CS. Potential underlying mechanisms related to urinary phosphate excretion and possibly involving FGF23, BMI and parathyroid hormone levels should be further explored.

Update on the Crosstalk Between Adipose Tissue and Mineral Balance in General Population and Chronic Kidney Disease

Adipose tissue is nowadays considered as a major endocrine organ, which apart from controlling lipid metabolism, displays a significant role in energy expenditure, food intake and in the regulation of various systemic physiological processes. Adipose derived pro-inflammatory cytokines and adipokines, particularly leptin and adiponectin, provide inter-communication of adipose tissue with various metabolic pathways, ultimately resulting in a complex network of interconnected organ systems. Recent clinical and experimental research has been focused on exploring the direct interaction between adipokine profile and elements of mineral metabolism, including parathormone (PTH), fibroblast growth factor-23 (FGF23) and calcitriol. The emerging crosstalk between adipose tissue and calcium and phosphorus homeostasis suggests that metabolic disorders from one system may directly affect the other and vice versa. It is current knowledge that fat metabolism disturbance, commonly encountered in obese individuals, influences the expression of calciotriopic hormones in general population, while various clinical trials attempting to successfully achieve body fat loss by modulating mineral profile have been published. In chronic kidney disease (CKD) state, there is an increasing evidence suggesting that mineral disorders, influence adipose tissue and linked endocrine function. On the contrary, the impact of disturbed fat metabolism on CKD related mineral disorders has been also evocated in clinical studies. Recognizing the pathogenetic mechanisms of communication between adipose tissue and mineral balance is critical for understanding the effects of metabolic perturbations from the one system to the other and for identifying possible therapeutic targets in case of disrupted homeostasis in one of the two connected systems. To that end, this review aims to enlighten the recent advances regarding the interplay between mineral metabolism, fat mass and adipokine profile, based on in vitro, in vivo and clinical studies, in general population and in the course of CKD.

Relationship between Serum 25(OH)D and Depression: Causal Evidence from a Bi-Directional Mendelian Randomization Study

The relationship between depression and vitamin D deficiency is complex, with evidence mostly from studies affected by confounding and reverse causality. We examined the causality and direction of the relationship between 25-hydroxyvitamin D (25(OH)D) and depression in bi-directional Mendelian randomization (MR) analyses using information from up to 307,618 white British participants from the UK Biobank and summary results from the SUNLIGHT (n = 79,366) and Psychiatric Genomics consortia (PGC 113,154 cases and 218,523 controls). In observational analysis, the odds of depression decreased with higher 25(OH)D concentrations (adjusted odds ratio (OR) per 50% increase 0.95, 95%CI 0.94–0.96). In MR inverse variance weighted (IVW) using the UK Biobank, there was no association between genetically determined serum 25(OH)D and depression (OR per 50% higher 0.97, 95%CI 0.90–1.05) with consistent null association across all MR approaches and in data from PGC consortium. In contrast, genetic liability to depression was associated with lower 25(OH)D concentrations (MR IVW −3.26%, −4.94%–−1.55%), with the estimates remaining generally consistent after meta-analysing with the consortia. In conclusion, we found genetic evidence for a causal effect of depression on lower 25(OH)D concentrations, however we could not confirm a beneficial effect of nutritional vitamin D status on depression risk.