Vitamin D deficiency in obese children and its relationship to glucose homeostasis

Customizing Nutrients: Vitamin D and Iron Deficiencies in Overweight and Obese Children-Insights from a Romanian Study

Background: Childhood obesity is a public health issue worldwide, recognized as a complex condition associated with multiple deficiencies in nutrients, such as vitamin D deficiency, iron-deficiency anemia, or abnormalities in serum calcium or phosphorus levels, despite an excess caloric intake. Objective: This study aims to investigate the prevalence of these deficiencies in overweight/obese children and to assess the correlation between vitamin D/serum iron levels and body mass index (BMI). Methods: The observational study was conducted on 69 Romanian overweight and obese children, aged 2 to 17, admitted to the Pediatrics Department of "Grigore Alexandrescu" Hospital in Bucharest over a 15-month period. The age- and gender-specific BMI percentiles were used to classify participants into three groups: overweight (≥85th and <95th BMI percentile), obese (≥95th BMI percentile), and severely obese (>120% of 95th BMI percentile). Data analysis focused on identifying the need for screening and targeted treatment in this pediatric population. Results: Hypovitaminosis D (defined as a serum level of 25(OH)D < 30 ng/mL) prevalence was significantly higher in the severe obesity category (71.5%) compared to the obesity (69%) and overweight (61.5%) groups. Iron deficiency and iron-deficiency anemia were both more prevalent in overweight children, with rates of 50% and 38.5%, respectively. Negative moderate correlations were found both between serum 25-hydroxyvitamin D levels and children's age (r = -0.444, p-value < 0.0001), as well as between serum 25(OH)D levels and BMI (r = -0.31, p = 0.015), with no statistically significant correlation between serum iron level and BMI in this cohort (r = -0.02, p > 0.05). Conclusions: Severe obesity could be regarded as an associated factor for vitamin D insufficiency as this is highly prevalent in severely obese children, with 25(OH)D levels decreasing with the increase in BMI. Overweight children demonstrated an increased prevalence of iron deficiency in the overweight category, suggesting that the adipose tissue contributes to chronic inflammation, disrupting iron homeostasis. Given the high prevalence of nutritional deficiencies in this population, implementing systematic screening and treatment programs would be beneficial to prevent long-term adverse outcomes.

A review of vitamin D deficiency and vitamin D receptor polymorphisms in endocrine-related disorders

The endocrine system is a complex network of glands that produce and release hormones that regulate various physiological processes. In the past few decades, the human skin has been identified as an important peripheral endocrine organ that is the main site for the synthesis of vitamin D through exposure to sunlight. Mutations in downstream vitamin D-related gene pathways are associated with disease development. The vitamin D receptor (VDR) gene, which regulates the pleiotropic effects of vitamin D, has been extensively studied in adult populations. Several studies have reported the prevalence of vitamin D deficiency in children and adolescents. With changes in socioeconomic status and lifestyle, vitamin D-deficient individuals are prone to developing the disease at a young age. However, geographical and racial differences affect the association between VDR gene polymorphisms and vitamin D endocrine disorders, explaining the nonconsensus effects of polymorphisms and their association with disease development across populations. In this review, we discuss the connection between the vitamin D endocrine system and polymorphisms in the gene encoding VDR in children and adolescents, focusing on its effects on growth, puberty, insulin resistance, and the immune system.

A bibliometric analysis and visualization of literature on the relationship between vitamin D and obesity over the last two decades

OBJECTIVE

The purpose of this study was to employ bibliometric analysis to visualize hot spots and evolving trends in the studies on the relationship between vitamin D and obesity.

METHODS

From the Web of Science Core Collection database, articles on vitamin D and obesity from 2001 to 2021 were retrieved. For the bibliometric visualization analysis, CiteSpace was employed. Some of the figures were created using GraphPad software.

RESULTS

4454 pieces of articles and reviews were found, with an average citation of 30.68 times. There are many more published papers in the area of "nutrition dietetics" (1166, 26.179 %). The United States possesses the largest number of publications (1297, 29.12 %) and demonstrates definitive leadership in this field. The League of European Research Universities generates a higher percentage of publications (256, 5.748 %) than other institutions. Major studies are funded by the United States Department of Health and Human Services (531, 11.922 %) and the National Institutes of Health, USA (528, 11.855 %). The top five keywords with the highest co-occurrence frequency are "obesity" (1260), "vitamin d" (943), "insulin resistance" (651), "risk" (642), and "d deficiency" (636). The biggest keyword cluster was #0 "adolescent" among the 18 keyword clusters. The three latest keywords in the keyword burst were "mineral density"、"d insufficiency" and "25 hydroxyvitamin d concentration".

CONCLUSION

This bibliometric analysis shows an overview of the current status of the research on the association between vitamin D and obesity. The prevalence of vitamin D deficiency and the relationship between vitamin D and metabolic syndrome in obese individuals remains hot topics. We speculate that the effect of obesity on vitamin D levels and bone mineral density, and the influence of vitamin D insufficiency on various body systems in obese populations will be future trends.

Association of Blood Calcidiol Levels and Metabolic Syndrome in Children and Adolescents With Vitamin D Deficiency

This retrospective cohort study aimed to determine whether severe calcidiol deficiency [25-hydroxyvitamin (OH)D <30 nmol/L] improvement has a beneficial effect on cardiometabolic parameters in children and adolescents (5-17 years) with or without metabolic syndrome (MetS). Logistic regression analysis was performed to test for multivariate associations between potential confounders and changes in vitamin D (VD) status from baseline to follow-up care when predicting binary categorical outcomes. Of 562 participants, 146 (26%) had MetS. Individuals with severe VD deficiency (VDD) were more likely to have MetS with elevated blood pressure than those with sufficient (≥75 nmol) VD levels (adjusted odds ratio [AOR], 4.46; 1.08-18.43; p < .05) at follow-up. In the logistic regression model, every unit increase in VD across time decreased the odds of MetS (AOR, 0.98; 95% confidence interval: [0.96, 0.99]; p < .05). Improvement in VD status demonstrated a beneficial metabolic effect in children and adolescents with severe VDD.

Investigating Vitamin D-Binding Protein's Role in Childhood Health and Development

Vitamin D-binding protein (DBP), also known as Gc-globulin, is a protein that affects several physiological processes, including the transport and regulation of vitamin D metabolites. Genetic polymorphisms in the DBP gene have a significant impact on vitamin D levels and may have implications for disease risk. DBP polymorphisms are linked to differential immune responses, which could influence the onset of juvenile diseases. This narrative review examines the various roles of DBP, with a focus on bone health, immunological regulation, and lipid metabolism in children. Chronic disorders affected by DBP polymorphisms include bone abnormalities, autoimmune diseases, cardiovascular issues, childhood asthma, allergies, cystic fibrosis, acute liver failure, celiac disease, inflammatory bowel disease, and chronic kidney disease. Future research should focus on identifying the processes that underpin the many roles that DBP plays and developing customized therapeutics to improve health outcomes in the juvenile population.

The prevalence of vitamin D deficiency and the factors affecting vitamin D levels in children admitted to the outpatient clinic of pediatric endocrinology in Bolu Province

BACKGROUND

The present study aimed to determine the rate of vitamin D deficiency in children who presented to the pediatric endocrinology outpatient clinic in Bolu and to investigate the factors affecting vitamin D levels.

METHODS

Vitamin D levels of 1008 children and adolescents were retrospectively analyzed according to age group (0-1, 1-10, and 10-18 years), gender, season, month, obesity and other diseases, and deficiency category. Moreover, calcium, phosphorus, alkaline phosphatase, and parathyroid hormone levels were evaluated. Comparisons and correlation analyses between related groups were performed.

RESULTS

The mean vitamin D level of the patients was 16.35±9.56 ng/mL and was lower in girls (14.90±9.56 ng/mL) than in boys (18.68±9.63 ng/mL, p<0.001). Overall, 18.3% of the children and adolescents had vitamin D insufficiency, 52.3% had vitamin D deficiency, and 3.5% had severe vitamin D deficiency. Vitamin D levels were lower in 10-18-year age group than in the other age groups (p<0.001), and levels were higher in summer and autumn than in winter and spring (p<0.001). Vitamin D levels of participants with obesity (14.3 ± 8.3 ng/mL) were significantly lower than normal-weight participants with no health problems (15.9 ± 8.3 ng/mL, p = 0.004). There was a negative correlation between vitamin D, alkaline phosphatase, and parathyroid hormone levels in the 1-10-year age group, but a positive correlation between vitamin D, alkaline phosphatase, and calcium levels in the 10-18-year age group.

CONCLUSION

The rate of vitamin D deficiency is high among children and adolescents who presented to the endocrine outpatient clinic in Bolu. The season appears to be an important factor affecting vitamin D levels as well as the relationship between vitamin D and parathyroid hormone. Obese children and adolescents living in this region may be advised to take vitamin D supplements in winter and spring.

Is more prolonged sun exposure associated with healthier life habits and obesity indicators in Portuguese children?

OBJECTIVES

Sun exposure seems to have an indirect effect on the development of obesity through vitamin D synthesis in the skin, the primary source of this vitamin. The present study aimed to investigate associations among sun exposure time, obesity indicators, and lifestyle habits in children.

METHODS

A total of 4755 children (3-10 years; 49.86% boys) from the north, center and south-central Portugal were included in the present study. During 2016/2017 children's sun exposure time, screen time, time devoted to the practice of physical activity and active play were collected through standard questionnaires answered by parents. Statistical analyses were conducted to investigate differences among sun exposure time according to the sex, age, obesity indicators and lifestyle habits.

RESULTS

Linear regression analysis showed that sun exposure time presented a negative association with Body Mass Index (β = -0.09, 95% CI: -0.18; -0.003; p = .042), body fat % (β = -0.31, 95%; CI: -0.54; -0.07; p = .010), computer time (β = -0.08, 95% CI: -0.12; - 0.05; p < .0001) and a positive association with active play time (β = 0.22, 95% CI: 0.17; 0.27; p < .0001) and total time of physical activity practice (β = 10.01, 95% CI: 4.52; 15.20; p < .0001).

CONCLUSIONS

The results reinforce the need for future guidance on the ideal sun exposure time, especially in children, who are at risk for vitamin D deficiency. Standardization of criteria for classifying optimal sun exposure time in this age group, considering the parameters that affect vitamin D status, such as age and seasonality, should be considered when planning future guidelines.

Mediation of BMI on 25-Hydroxyvitamin D Levels in U.S. Adults with Sugar-Sweetened Beverages Consumption

Body mass index (BMI) as well as sugar-sweetened beverages (SSB) has been suggested to independently decrease 25-hydroxyvitamin D (25(OH)D). However, the relationship between SSB, BMI, and 25(OH)D is uncertain. This study aimed to investigate the potential mediating role of BMI in the association between SSB intake and 25(OH)D. A total of 4505 representative U.S. adults aged above 20 years and without liver conditions were selected from the 2013-2014 NHANES. All analyses were performed under survey modules with appropriate sampling weights. The prevalence of 25(OH)D insufficiency and deficiency was 37.8% and 24.1% in U.S. adults, respectively. Compared with non-SSB consumers, an increased risk of vitamin D deficiency was found in either heavy SSB consumers or soda consumers, respectively (aOR = 2.10, 95% CI = 1.25-3.54 in heavy SSB consumers; aOR = 1.61, 95% CI = 1.06-2.44 in soda consumers). Around 21.3% of the total effect of sugar intake from SSB on decreased 25(OH)D was explained by BMI. In conclusion, high total sugar intake from SSB and BMI independently contribute to lower 25(OH)D, and BMI mediates the inverse association between total sugar intake from SSB intake and 25(OH)D. Furthermore, an increased risk of having vitamin D deficiency was found in the population who consumed higher levels of sugar from SSB or soda drinks.

Associations between vitamin D levels and dietary patterns in patients with Hashimoto's thyroiditis

Introduction

Vitamin D insufficiency is a global health problem affecting healthy and diseased individuals, including patients with Hashimoto's thyroiditis (HT). Identifying dietary factors that may affect vitamin D levels and providing dietary guidelines accordingly can alleviate this problem. We therefore aimed to identify still unknown associations of dietary patterns, assessed through the Food Frequency Questionnaire (FFQ) with vitamin D blood levels.

Materials and methods

FFQ was collected from 459 patients from Croatian Biobank of Patients with Hashimoto's thyroiditis (CROHT), while total 25(OH)D was measured from their stored serum samples. We performed linear regression analysis between vitamin D levels and weekly intake of 24 food groups in 459 patients with HT (ALL), and in two disease-severity groups (MILD and OVERT).

Results

The main results of our study are observations of: (1) an inverse association between vitamin D levels and coffee consumption (ALL: β = -0.433, p = 0.005; OVERT: β = -0.62, p = 0.008); (2) an inverse association between vitamin D levels and sweets consumption (ALL: β = -0.195, p = 0.034; OVERT: β = -0.431, p = 0.006); (3) positive association between vitamin D levels and vegetable consumption (ALL: β = 0.182, p = 0.019; OVERT, β = 0.311, p = 0.009). Importantly, effect sizes of all three associations were more prominent in HT patients with prolonged and more severe disease (OVERT).

Conclusion

Further research into the functional and causal relationships of the observed associations is important to provide guidance regarding coffee/sugar intake on vitamin D status. A well-balanced diet can help prevent vitamin D deficiency and improve the quality of life of patients with HT, especially those in later stages of disease characterized by greater metabolic imbalance.

The link between vitamin D, chemerin and metabolic profile in overweight and obese children - preliminary results

Background

Vitamin D affects adipogenesis, oxidative stress, inflammation, secretion of adipocytokines, lipid metabolism and thermogenesis. Some researchers postulate that those effects could be exerted by the influence of vitamin D on chemerin levels.

Aim of the study

We aimed to investigate if there is a link between serum 25-hydroksyvitamin D [25(OH)D], chemerin and metabolic profile in overweight and obese children before and after vitamin D supplementation.

Material and methods

The prospective study included 65 overweight and obese children aged 9.08-17.5 years and 26 peers as a control. None of the patients in the study group had received vitamin D within the last twelve months before the study.

Results

The study group had lower baseline 25(OH)D (p<0.001) and higher chemerin (p<0.001), triglycerides (TG, p<0.001), triglycerides/high density lipoprotein cholesterol (TG/HDL-C, p<0.001), C-reactive protein (CRP, p<0.05), fasting insulin (p<0.001), Homeostasis Model Assessment - Insulin Resistance (HOMA-IR, p<0.001), alanine aminotransferase (ALT, p<0.001) and uric acid (p<0.001) compared to the control group. Baseline vitamin D was related to fasting insulin (R=-0.29, p=0.021), HOMA-IR (R=-0.30, p=0.016), HDL-C (R=0.29, p=0.020) and uric acid (R=-0.28, p=0.037) in the study group. Baseline chemerin was related to insulin at 30' (R=0.27, p=0.030), 60' (R=0.27, p=0.033), 90' (R=0.26, p=0.037) and 120' (R=0.26, p=0.040) during the oral glucose tolerance test (OGTT) and ALT (R=0.25, p=0.041) in the study group. Correlation between vitamin D and chemerin (R=-0.39, p=0.046) was found only in the control group. After six months of vitamin D supplementation a decrease in CRP (p<0.01), total cholesterol (p<0.05), ALT (p<0.01), glucose at 150' OGTT (p<0.05) was observed. Moreover, we noticed a tendency for negative association between 25(OH)D and chemerin levels (p=0.085). Multivariable backward linear regression models were build using baseline vitamin D, baseline chemerin and six months chemerin as the dependent variables.

Conclusions

Our study confirmed that vitamin D has positive effect on metabolic profile in overweight and obese children. The relationship between vitamin D and chemerin is not clear, nevertheless we have observed a tendency to decrease chemerin concentrations after improving vitamin D status, even without a significant reduction in body fat mass.

Vitamin D deficiency and cardiometabolic risk factors in adolescents: systematic review and meta-analysis

Vitamin D deficiency is associated with an increase in the occurrence of cardiometabolic events, but the evidence of this relationship in adolescence is still limited. Thus, we analyzed the association between vitamin D deficiency and cardiometabolic risk factors in adolescents. Observational studies were searching in PubMed/Medline, Embase, Scopus, Web of Science, Science Direct, Lilacs, and Google Scholar database. Random effects models were used to summarize standardized mean differences for as a summary measure. The certainty of the evidence was verified using the Cochrane recommendations. A total of 7537 studies were identified, of which 32 were included in the systematic review and 24 in the meta-analysis.Vitamin D deficiency was associated with increased systolic pressure (SMD = 0.22; 95%CI = 0.10; 0.34), diastolic pressure (SMD = 0.23; 95%CI = 0.10; 0.35), glycemia (SMD = 0.13; 95%CI = 0.05; 0.12), and insulin (SMD = 0.50; 95%CI = 0.15; 0.84), an increase in the HOMA index (SMD = 0.48; 95%CI = 0.36; 0.60), high triglyceride values (SMD = 0.30; 95%CI = 0.11; 0.49), and reduced HDL concentrations (SMD= -0.25; 95%CI = -0.46; -0.04). No statistically significant association was observed for glycated hemoglobin, LDL cholesterol, and total cholesterol. Most of the studies presented low and moderate risks of bias, respectively. The certainty of the evidence was very low for all the outcomes analyzed. Vitamin D deficiency was associated with increased exposure to the factors linked to the occurrence of cardiometabolic diseases in adolescents. Systematic Review Registration: PROSPERO (record number 42,018,086,298).

Treatment of Diabetes and Osteoporosis—A Reciprocal Risk?

Diabetes mellitus is a metabolic and systematic disorder that requires individualized therapy. The disease leads to various consequences, resulting in the destruction of tissues and organs. The aforementioned outcomes also include bone mineral disorders, caused by medications as well as diet therapy and physical activity. Some drugs may have a beneficial effect on both bone mineral density and the risk of fractures. Nevertheless, the impact of other medications remains unknown. Focusing on pharmacotherapy in diabetes may prevent bone mineral disorders and influence both the treatment and quality of life in patients suffering from diabetes mellitus. On the other hand, anti-osteoporosis drugs, such as antiresorptive or anabolic drugs, as well as drugs with a mixed mechanism of action, may affect carbohydrate metabolism, particularly in patients with diabetes. Therefore, the treatment of diabetes as well as osteoporosis prevention are vital for this group of patients.

Associations of Serum Total 25OHD, 25OHD3, and epi-25OHD3 with Insulin Resistance: Cross-Sectional Analysis of the National Health and Nutrition Examination Survey, 2011–2016

Background: Vitamin D may have a role in insulin sensitivity. However, the data on the association between various metabolites of Vitamin D and insulin-related parameters have been limited. Methods: We identified 6026 adults aged 20–80 years who participated in the 2011–2016 National Health and Nutrition Examination Survey (NHANES). Serum total 25OHD, 25OHD3, and epi-25OHD3, fasting glucose, insulin, and HOMA2-IR were obtained from the NHANES data. The association between serum Vitamin D-related values and insulin resistance was analyzed using a generalized linear model. For risk analysis, multifactorial logistic regression was used. Results: The median total 25-hydroxyvitamin D level, 25-hydroxyvitamin D3 level, and 3-epi-25-hydroxyvitamin D3 level were 62.5 nmol/L, 58.8 nmol/L, and 3.3 nmol/L, respectively. After adjustment for sex, age, race, ethnicity, and education status, the ORs for the insulin resistance of participants of total 25-hydroxyvitamin D, 25-hydroxyvitamin D3, and 3-epi-25-hydroxyvitamin D3 were 0.32 (95% CI 0.24, 0.43), 0.34 (95% CI 0.26, 0.44), and 0.64 (95% CI 0.53, 0.77), respectively. After an adjustment for body mass index, diabetes, and drinking and smoking, the ORs for the insulin resistance of the participants for total 25-hydroxyvitamin D, 25-hydroxyvitamin D3, and 3-epi-25-hydroxyvitamin D3 were 0.56 (95% CI 0.40, 0.78), 0.63 (95% CI 0.46, 0.85), and 0.99 (95% CI 0.80, 1.24), respectively. Conclusions: Our study provides suggestive evidence for the association between Vitamin D concentrations and a lower risk of insulin resistance. Evidence from larger and more adequately powered cohort studies is needed to confirm our results.

Acanthosis Nigricans Is a Strong Predictor of Low Blood Calcidiol Levels in Children and Adolescents

Background: Clinical consensus differs as to when blood vitamin D (VD) levels should be measured in children. Obesity and metabolic syndrome are risk factors for low VD levels and are also associated with acanthosis nigricans (AN). Objectives: To test whether the clinical diagnosis of AN is a strong predictor for vitamin D deficiency (VDD) in children. Methods: Within the study period (2015-2020), we identified 677 consecutive individuals (age <18 years) with available calcidiol measurements and compared those with (n = 273) and without (n = 404) AN. Bivariate associations and the occurrence of AN were tested using the chi-squared test. Multivariate logistic regression was performed to control for confounding variables, and adjusted odds ratios with 95% confidence intervals (CI) were reported. Multiple regression analysis was performed, and unstandardized beta coefficients, standard errors, and standardized beta coefficients were reported. Results: Individuals with AN had 3.6 times higher odds of VDD than those without (95% CI: 1.38-9.51, P = 0.009). Males had 0.41 times lower odds of having AN than females (95% CI: 0.21-0.79, P = 0.008). Individuals with vitamin D sufficiency (VDS) were much less likely to be diagnosed with metabolic syndrome compared with those who were vitamin D deficient (P = 0.011), even after adjusting for body mass index z-scores. Conclusion: Children and adolescents with AN are at a higher risk of VDD and should likely be tested for low calcidiol levels.

Overview of Nutraceuticals and Cardiometabolic Diseases following Socio-Economic Analysis

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

Vitamin D as a biomarker of health in snoring children: a familial aggregation study

BACKGROUND

Hypovitaminosis D is a common health problem. The purpose of this study was to investigate the inter-relationship between serum 25(OH)D levels and paternal and maternal vitamin D status in a sample of snoring children.

METHODS

We selected 137 participants for whom serum 25(OH)D had been measured and underwent overnight polysomnography evaluation. Serum glucose, lipids, liver enzymes, parathyroid hormone, insulin, and glycated hemoglobin were also measured. Glucose and insulin levels were used to estimate insulin resistance with the homeostasis model assessment (HOMA-IR).

RESULTS

Vitamin D insufficiency (<30 ng/mL) and deficiency (<20 ng/mL) were found in 40.9 and 17.5% of children, respectively. After adjustments for age, BMI z-score and seasonality, the odds ratio for risk of vitamin D insufficiency according to the vitamin D status of parents were: OR (95% CI): paternal insufficiency 15.1 (2.7-35.7), p = 0.002; maternal insufficiency 7.2 (2.4-22), p = 0.001. When children with vitamin D deficiency were analyzed separately, serum 25(OH)D concentration was found to be associated with the apnea-hypopnea index (r = -0.647, p = 0.009) and respiratory arousal index (r = -0.669, p = 0.034).

CONCLUSIONS

Family patterns of vitamin D could be helpful for the early identification of children at risk of metabolic and/or sleep disturbances and when considering strategies to improve vitamin D status.

IMPACT

Family patterns of vitamin D could be helpful for the early identification of snoring children at risk of metabolic and/or sleep disturbances. Significant associations were found between serum 25-hydroxyvitamin D (25(OH)D) concentrations in children and their parents. An inverse association between 25(OH)D levels and OSA severity was detected in deficient vitamin D children. Children with insufficient and deficient vitamin D status tended to have a worse metabolic profile, so strategies are needed to improve vitamin D status.

Vitamin D and Calcium Status Among Adolescents with Morbid Obesity Undergoing Bariatric Surgery

PURPOSE

Obesity is very prevalent among children and adolescents these days. Obese children are at increased risk of vitamin D and other micronutrient deficiencies. This risk is even higher in children and adolescents with morbid obesity who are candidates for bariatric surgery. Although multiple studies have studied the prevalence of vitamin D deficiency in adults undergoing bariatric surgery, studies are limited concerning adolescents in this regard. We aimed to study the prevalence of vitamin D deficiency and insufficiency and calcium status among morbidly obese children and adolescents.

MATERIALS AND METHODS

A number of 96 adolescents (20 years old and younger) with morbid obesity (BMI ≥ 99% percentile), who were candidates for bariatric surgery, were enrolled in this study (from 2016 to 2018), and their serum vitamin D and calcium levels were measured.

RESULTS

Sixty-four percent of the patients were vitamin D-deficient and 15.7% of them had insufficient levels of serum vitamin D. Only 20.2% of the children had sufficient serum vitamin D levels. Serum calcium levels were within the normal range among all of the patients. There was no significant relationship between age and sex with vitamin D levels.

CONCLUSION

Vitamin D deficiency is of very high prevalence among adolescents with morbid obesity.

Vitamin D supplementation and cardiometabolic risk factors among diverse schoolchildren: a randomized clinical trial

BACKGROUND

There remains a lack of evidence demonstrating a potential relationship between vitamin D and cardiometabolic risk among children.

OBJECTIVES

We examined the effect of 3 different dosages of vitamin D on cardiometabolic risk factors among children at risk of deficiency.

METHODS

Racially diverse schoolchildren aged 8-15 y were randomly assigned in a double-blind fashion to supplementation with 600, 1000, or 2000 IU vitamin D3/d for 6 mo. Changes in HDL cholesterol, triglycerides, LDL cholesterol, total cholesterol, and blood glucose over 6 mo and at 12 mo (6 mo post-supplementation) were assessed. Subgroup analyses were also performed by weight status and race.

RESULTS

Among 604 children, 40.9% were vitamin D-inadequate at baseline (<20 ng/mL; mean ± SD: 22.0 ± 6.8 ng/mL), 46.4% were overweight/obese, and 60.9% had ≥1 suboptimal blood lipids or glucose. Over 6 mo, serum 25-hydroxyvitamin D increased in all 3 dosage groups from baseline (mean ± SE change: 4.4 ± 0.6 ng/mL, 5.7 ± 0.7 ng/mL, and 10.7 ± 0.6 ng/mL for 600, 1000, and 2000 IU/d, respectively; P < 0.001). Whereas HDL cholesterol and triglycerides increased in the 600 IU group (P = 0.002 and P = 0.02, respectively), LDL cholesterol and total cholesterol decreased across dosage groups. At 6 mo post-supplementation, HDL cholesterol remained elevated in the 600 and 1000 IU groups ( P < 0.001 and P = 0.02, respectively) whereas triglycerides remained elevated in the 1000 and 2000 IU groups (P = 0.04 and P = 0.006, respectively). The suppression of LDL cholesterol and total cholesterol persisted in the 2000 IU group only (P = 0.04 and P < 0.001, respectively). There were no significant changes in blood glucose and similar responses were observed overall by weight status and racial groups across dosages.

CONCLUSIONS

Vitamin D supplementation demonstrated generally positive effects on HDL cholesterol, LDL cholesterol, and total cholesterol, especially at the lower dosage of 600 IU/d, with several significant changes persisting during the post-supplementation period. Increases in triglycerides across dosage groups may be due to natural changes during adolescence warranting further study.This trial was registered at clinicaltrials.gov as NCT01537809.

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

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

Association of vitamin D receptor polymorphisms with metabolic syndrome-related components: A cross-sectional study

BACKGROUND

The association between vitamin D receptor (VDR) polymorphisms and metabolic syndrome (MS) has been demonstrated by epidemiological studies while their correlation remain controversial. The aim of this study is to investigate the association of VDR gene polymorphisms with MS and MS-related components in the two communities of Hangzhou.

METHODS

A total of 394 subjects were enrolled in the cross-sectional study. Four VDR gene polymorphisms (ApaI, BsmI, FokI, and TaqI) were selected based on human genome sequence databases and genotyped using the MassARRAY Analyzer Compact.

RESULTS

In lipid profile, the TT genotype of ApaI had a significantly lower risk of hypertriglyceridemia compared with the GG+GT genotypes (recessive model: OR = 0.141; 95% CI = 0.041-0.486; p < 0.01) and the GG genotype (codominant model: OR = 0.155; 95% CI = 0.044-0.545; p < 0.01). The levels of triglyceride (TG) in the TT genotype of ApaI were lower than the GG+GT genotypes (1.29 ± 0.63 vs. 1.78 ± 1.59 mmol/L, p < 0.01). Furthermore, the AA+GA carriers of BsmI had lower levels of high-density lipoprotein cholesterol (HDL-C) than the GG carriers (1.28 ± 0.29 vs. 1.42 ± 0.34 mmol/L, p < 0.05). The CC+TC carriers of TaqI also suffered from lower HDL-C compared with the TT carriers (1.27 ± 0.29 vs. 1.42 ± 0.34 mmol/L, p < 0.01). For arterial blood pressure, the CC carriers had lower systolic blood pressure (SBP) than the TT+TC carriers (p < 0.01) and the TT carriers of FokI (p < 0.05). However, the FokI polymorphisms were not associated with SBP and the mean blood pressure of both groups laid within the normal range.

CONCLUSIONS

In our study, VDR polymorphisms show no association with the MS risk. The present results suggest that the VDR ApaI polymorphism is associated with hypertriglyceridemia and predisposed to developing MS, while the variants of BsmI and TaqI seem to affect HDL-C. Nevertheless, the effect of FokI variants with SBP is ambiguous.

Vitamin D deficiency in children and adolescents with obesity: a meta-analysis

OBJECTIVE

To evaluate the prevalence of vitamin D deficiency in obese children and adolescents when compared to eutrophic controls.

METHODS

Systematic review with meta-analysis covering studies with patients aged 0-18 years old diagnosed with obesity and vitamin D deficiency and control group of eutrophic patients. The studies were retrieved in the PubMed, Embase, and LILACS databases in December 2019. The search used the terms "obesity" in combination with "pediatric population" and "vitamin D".

RESULTS

Through the search 3155 articles were retrieved; and after analysis, 20 studies were selected according to the study objectives. A total of 24,600 children and adolescents were included. Through meta-analysis, the relative risk for the association between obesity and vitamin D deficiency in the pediatric population was 1.41 (95% CI: 1.26-1.59) (I² = 89%, p < 0.01).

CONCLUSION

Children and adolescents with obesity have higher risk of vitamin D deficiency.

Effects of Vitamin D Supplementation on CD4+ T Cell Subsets and mTOR Signaling Pathway in High-Fat-Diet-Induced Obese Mice

Obesity is associated with an impaired balance of CD4⁺ T cell subsets. Both vitamin D and obesity have been reported to affect the mTOR pathway. In this study, we investigated the effects of vitamin D on CD4⁺ T cell subsets and the mTOR pathway. Ten-week-old male C57BL/6 mice were divided into four groups and fed diets with different fat (control or high-fat diets: CON or HFD) and vitamin D contents (vitamin D control or supplemented diets: vDC or vDS) for 12 weeks. T cells purified by negative selection were stimulated with anti-CD3/anti-CD28 mAbs and cultured for 48 h. The percentage of CD4⁺IL-17⁺ T cells was higher in the vDS than vDC groups. The CD4⁺CD25⁺Foxp3⁺ T cells percentage was higher in HFD than CON groups. The phospho-p70S6K/total-p70S6K ratio was lower in vDS than vDC, but the phospho-AKT/total-AKT ratio was higher in vDS than vDC groups. Hif1α mRNA levels were lower in vDS than vDC groups. These findings suggest HIF1α plays an important role in vitamin-D-mediated regulation of glucose metabolism in T cells, and dietary vitamin D supplementation may contribute to the maintenance of immune homeostasis by regulating the mTOR pathway in T cells.

Lipid profile of childhood cancer survivors and the effects of vitamin D supplementation: a prospective study

Background

Childhood cancer survivors (CCS) have high prevalence of obesity vitamin D (VD) deficiency together with dyslipidemia. We aimed to evaluate lipid profile and the effect of VD supplementation in CCS.

Results

VD deficiency was more frequent among obese CCS and their lipid profiles, TC, and LDL-C levels were significantly higher compared to non-obese patients. After VD supplementation trials, VD levels increased among obese and non-obese children albeit it was significantly higher in non-obese subjects while the lipid profile of obese patients significantly decreased. Also, parathyroid hormone levels were persistently elevated among VD-deficient obese patients. Yet, the weight of obese patients remained unchanged.

Conclusion

VD deficiency was more prevalent among obese CCS. VD supplementation helped in normalization of the lipid profile of obese CCS. Regular measurement of PTH and 25OH-VD is recommended for CCS especially obese ones who may need VD supplementation.

Vitamin D status and blood pressure in children and adolescents: a systematic review of observational studies

BACKGROUND

Childhood hypertension is a growing public health problem. Simultaneously, hypovitaminosis D is widespread in this population and could be associated with hypertension. This study systematically reviewed the literature on the relationship between vitamin D status and blood pressure (BP) in children and adolescents.

METHODS

Following the PRISMA guidelines, PUBMED, MEDLINE, CINAHL, EMBASE, Cochrane Library, and ClinicalTrials.gov and the gray literature without language or time restrictions were searched. We included observational studies, assessed their risk of bias, and extracted data on population characteristics, vitamin D status and BP measurements, and the association between the two variables. A narrative analysis of the studies was performed.

RESULTS

In total, 85 studies were included. Prospective cohort studies showed no association between vitamin D and BP, and generally, they were flawed. Also, the majority of non-prospective cohort studies (cross-sectional, retrospective, case-control) did not report an association between vitamin D and BP. They were mostly flawed regarding BP measurement and adjusting to potential confounders.

CONCLUSION

The results on the relationship between vitamin D status and BP in children and adolescents varied between the studies, and mainly pointed towards lack of association.

Vitamin D - current stage of knowledge about analysis and supplementation

Nowadays, topics related to the proper nutrition of the body, which requires a complex of compounds and supplementation of these ingredients have undoubtedly gained popularity, so it should come as no surprise that there is a widespread interest in vitamin D in science, medicine, analytics and nutrition. In the world of developing technologies, new directions of physiological action of this vitamin on the body are being discovered. Issues related to the demand for vitamin D in various populations and its sources in food, the appropriate form of supplementation, safety and toxicity are extremely important. The present manuscript focuses on the concise evaluation of key data in the field of vitamin D. Structure and physicochemical properties, demand and delivery trails, deficiency and its diagnosis, supplementation, interactions of vitamin D with supplements and drugs are discussed. Attention has also been paid to the methods of vitamin D analysis in various matrices, which allow for an accurate and precise quality assessment of dietary supplements, drugs and food products. The presented information allows deeper understanding of the mechanisms responsible for the development of many diseases in the context of vitamin D levels.

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.

Vitamin D Insufficiency is Not Associated With Pediatric and Adolescent Immune Thrombocytopenia: A Study in Conjunction With its Receptor Genetic Polymorphisms

Idiopathic thrombocytopenic purpura (ITP) is a heterogeneous immunologic disorder. Vitamin D has immune-modulatory effects. The pleiotropic effects of vitamin D are exerted via vitamin D receptor (VDR) and its genetic alterations could influence its functions. In our study, we measured the serum 25-hydroxyvitamin D levels in 98 Pediatric and Adolescent ITP patients, in addition to 100 apparently healthy controls. Genetic polymorphisms of the VDR gene FokI, BsmI, ApaI, and TaqI were tested using specific restriction enzymes for each polymorphism. Vitamin D deficiency in the studied Pediatric age was a dominant factor, but it was found not to be associated with Pediatric ITP. However, patients carrying the FokI CC genotype had statistically higher vitamin D levels compared with those carrying other genotypes (P=0.036). Patients who were carriers of the BsmI G allele had a nearly 2-fold higher risk of ITP (odds ratio: 2.203; 95% confidence interval: 1.467-3.309). Therefore, the BsmI polymorphism of VDR could be considered a molecular risk factor for ITP.

Screening for Bone Mineral Density and Assessment Knowledge Level of Low Peak Bone Risk Factors and Preventive Practices Among Kuwaiti Future Mothers

Background

Attaining greater peak bone mass (PBM) prior to the onset of bone loss is getting increasing public health attention as healthy strong bones are essential to maintain our life. Females are more susceptible to bone loss. Knowledge and awareness about low peak bone mass and its related risk factors are important contributors to its preventive behavior.

Objective

To screen apparently healthy young Kuwaiti future mothers for low bone mineral density (BMD) and to assess their knowledge level about determinants of PBM and preventive practices.

Methods

A cross-sectional comparative study on 445 eligible women aged 18–35 years (either students or employees from Kuwait University) was performed. Data on socio-demographic and lifestyle variables were obtained by a semi-structured questionnaire. Their knowledge was assessed using the modified Osteoporosis Knowledge Assessment Tool (OKAT). Bone mineral Density (BMD) was measured using Quantitative Ultrasonography (QUS).

Results

More than half (59.3%) of females had poor knowledge. A statistically significant relation was noted between the overall knowledge score and age, college, occupation, and socioeconomic class (P<0.05 for each). Only 13.9% have low Z-score by QUS. By logistic regression, less carbonated beverages and coffee consumption positively affect BMD, while inadequate exercises level, indoor exposure to sunlight, and less frequency of brisk walking negatively affect BMD.

Conclusion

Unacceptable knowledge score significantly associated with BMD Z-score status. More attention should be devoted to education programs targeting adolescents and young females to promote knowledge about PBM and practice towards accrual and maintenance of bone health.

Serum 25-hydroxyvitamin D is associated with insulin resistance independently of obesity in children ages 5-17

AIM

To determine the association of vitamin D with insulin resistance and obesity in children.

METHODS

A total of 92 obese and 58 non-obese children aged 5-17 years were evaluated. Data were collected related to anthropometric (weight, height), and biochemical parameters (fasting plasma glucose, serum insulin, serum 25-hydroxyvitamin D, lipid profile, vitamin B12, parathormone) and physical examination (blood pressure, acanthosis nigricans, stria, lipomastia). Insulin resistance (IR) was calculated using the homeostasis model assessment (HOMA). HOMA-IR = fasting insulin level (μU/ml) × fasting glucose (mg/dL)/405. A HOMA-IR value >2.5 was defined as insulin resistance.

RESULTS

According to the US Endocrine Society classification, vitamin D deficiency (0-20 ng/ml) was determined at significantly higher rates in the obese group than in the control group (p < 0.001). The rate of subjects with a vitamin D level of 20-30 ng/ml was significantly lower in the obese group than in the control group (p < 0.001) Within the obese group a statistically significant difference was determined between the insulin resistant and non-insulin resistant groups in respect of serum 25-hydroxyvitamin D levels (p = 0.001) and vitamin B12 levels (p = 0.001). A significant negative correlation was determined between serum 25-hydroxyvitamin D and HOMA-IR (r=-0.256, p = 0.016) and insulin (r = -0.258, p = 0.015). The systolic blood pressure (p = 0.001) and diastolic blood pressure (p = 0.003) values were significantly different in the control and obese groups. A statistically significant difference was determined between the control and obese groups in terms of the levels of insulin, HOMA-IR, HbA1c, cortisol, LDL, total cholesterol, HDL, triglyceride, hemoglobin, MCV, MPV, and calcium.

CONCLUSION

The prevalence of vitamin D deficiency was higher in obese children compared to normal-weight and overweight children. Serum 25(OH)D levels showed a negative correlation with insulin and HOMA-IR. Serum 25(OH)D is associated with insulin resistance independently of obesity.

Vitamin D supplementation in obese Sri Lankan children: a randomized controlled trial

Background

Micronutrient deficiencies are identified among obese individuals. Vitamin D deficiency (VDD) is prevalent in obese children, and is hypothesized to cause insulin resistance and metabolic abnormalities. This study aimed to determine the effect of vitamin D supplementation on obesity and related metabolic abnormalities among obese Sri Lankan children with VDD.

Methods

A triple-blind randomized controlled trial was conducted among vitamin D deficient (< 20 ng/ml), obese children (n = 96), randomly allocated to three intervention arms - treatment arm receiving weekly vitamin D₂ 50,000 IU; supplementation arm receiving 2500 IU weekly and control arm, receiving placebo. Anthropometry, percentage fat mass (%FM) and blood pressure were assessed and fasting blood glucose, fasting insulin, lipid profile, aspartate transaminase (ALT), alanine transaminase (AST), vitamin D, parathyroid hormone (PTH) and hs-CRP and OGTT with 2-h random blood glucose and insulin was performed at baseline and after 24 weeks of treatment. Ethics Review Committee of Faculty of Medicine, University of Colombo approved the protocol.

Results

Waist circumference Z-score, %FM and serum calcium significantly improved across all three arms, ALT significantly improved in treatment and supplementation arms while, BMI Z-score, PTH and vitamin D significantly improved in the treatment arm. Biceps (p = 0.035) and subscapular (0.048) skin fold thickness, vitamin D (p = 0.004) and ALT (p = 0.012) significantly improved in the treatment arm.

Conclusions

A strict dietary and physical activity regimen could improve some of the anthropometric, body composition and metabolic profiles, but high dose vitamin D, enhances those improvements. Therefore high dose vitamin D seems to potentiate management outcomes of obese children with vitamin D deficiency.

Trial registration

The study was registered at the Sri Lanka Clinical Trials Registry (SLCTR/2015/017) on 12th September 2015 at https://slctr.lk/trials/slctr-2015-017.

An Ecological Approach to Obesity in Mexican American Children

INTRODUCTION

The objective of this study was to explore the risk factors that contribute to obesity in Mexican American children compared with Mexican American normal weight children. No hypotheses were tested in the study. When risk factors are known, nurses can use evidence to reduce risky behavior.

METHOD

A cross-sectional descriptive design was used, comparing two groups of children to discern the risk factors for obesity. The setting is a county in South Texas along the border with Mexico. The sample consisted of 55 Mexican American dyads (mother-child). The following measures, based on the Ecological Model of Growth, were used to collect data: anthropometrics, dietary data of children, home environment, perceived stress of mother, and maternal acculturation. Independent sample t tests, chi-square tests, Fisher exact tests, and a hierarchical logistic regression analysis were used to analyze the data.

RESULTS

The findings show children's age and maternal body mass index (BMI) are positively correlated with childhood obesity, as measured by BMI percentile by age/sex. There were significant differences in the host and agent factors of prolonged bottle feeding, amount of outdoor play, and fruit drinks between normal weight and obese children.

DISCUSSION

Engagement and involvement of other family members in outdoor activities, nutrition/feeding, and child care may mitigate the negative effects of host and agent factors on child body size.

Association of Vitamin D and Parathyroid Hormone Levels in Overweight and Obese Adolescents

Vitamin D deficiency in known to be high in obese and overweight adolescents. Few studies in other countries have shown lower parathyroid hormone (PTH) levels in obese adolescents despite high vitamin D deficiency. The aim of the study is to assess vitamin D and PTH levels and their relationship in overweight and obese adolescents in Telangana. This cross-sectional study was carried out in 108 overweight and obese boys and girls aged 12-18 years. A pretested Questionnaire was administered to collect information on demographics, sun exposure, medical and nutritional history. Anthropometry and blood sample was collected for estimating 25 hydroxy vitamin D, and PTH. Body mass index Z scores (WHO growth standards) were used for assessing overweight and obesity in adolescents. 54.6% of the subjects were boys. Mean (SD) levels of vitamin D and PTH were 18.25 (9.26) ng/mL and 45.39 (28.23) ng/L respectively. The prevalence of vitamin D deficiency and insufficiency in the current study was 54.6% and 25.9% respectively. However, PTH levels were high only in 24.2% of subjects (> 65 ng/L). There was an inverse but non-significant correlation between vitamin D and PTH. The association was same after adjusting for age, gender and weight. Our study highlights the high prevalence of vitamin D deficiency among overweight and obese adolescents in Telangana. Despite high vitamin D deficiency, very few had high PTH levels and the vitamin D-PTH axis may be altered in overweight and obese adolescents.

The Relationship of Serum 25-Hydroxyvitamin-D Level with Severity of Obstructive Sleep Apnea in Patients with Type 2 Diabetes Mellitus

OBJECTIVE

To explore the association of serum vitamin-D levels with the severity of obstructive sleep apnea (OSA) in patients with type 2 diabetes mellitus (T2DM).

METHODS

A cross-sectional study of 136 patients with T2DM who underwent overnight polysomnography (PSG) tests and serum 25-hydroxyvitamin-D3 (25(OH)D3) level detections was conducted. Multivariable linear regression and logistic regression analyses were performed to determine the associations of serum 25(OH)D3 levels with apnea-hypopnea index (AHI) and obstructive sleep apnea (OSA).

RESULTS

The prevalence rates of OSA were 84.4% for male and 65.2% for female patients, respectively (p = 0.011). With increasing severities of OSA categories (none, mild, moderate and severe), patients were more likely to be male and obese, but there was no significant difference in serum 25(OH)D3 level ((mean ± standard deviation) 21.8 ± 8.8, 27.7 ± 14.6, 24.2 ± 9.8 and 26.8 ± 6.2 ng/mL, respectively, p=0.086). Serum 25(OH)D3 level was not significantly correlated with AHI (log-transformed), with the correlation coefficient of 0.133 (p=0.124). With adjustment for potential confounding factors, multivariable linear regression and logistic regression analyses showed that serum 25(OH)D3 level was not significantly associated with either AHI (log-transformed) or the risk of OSA, with the standardized regression coefficient (95% confidence interval (CI)) of 0.098 (-0.004-0.014, p=0.252) and the adjusted odds ratio (95% CI) of 1.055 (0.991-1.124, p=0.095), respectively.

CONCLUSION

Serum 25(OH)D3 level was not significantly associated with either AHI or the risk of OSA in patients with T2DM.

Vitamin D status in preschool children and its relations to vitamin D sources and body mass index-Fish Intervention Studies-KIDS (FINS-KIDS)

OBJECTIVES

The aims of this study were to determine vitamin D status (serum 25-hydroxyvitamin D₃ [s-25(OH)D₃]) and examine possible associations between vitamin D status and vitamin D-rich dietary sources, sun exposure, and body mass index in preschool children ages 4 to 6 y.

METHODS

This is a cross-sectional study based on baseline data (collected in January-February 2015) from the two-armed randomized controlled trial Fish Intervention Studies-KIDS (FINS-KIDS) conducted in Bergen, Norway. S-25(OH)D₃ concentration was determined by liquid chromatography-tandem mass spectrometry. Information regarding habitual dietary intake, recent sun vacations, and body mass index were assessed with questionnaires answered by the children's caregivers.

RESULTS

The children (n = 212) had a mean (standard deviation) s-25(OH)D₃ of 60.7 (13.8) nmol/L; 18.9% had s-25(OH)D₃ ≤50 nmol/L. In logistic regression models, non-overweight versus overweight status was inversely associated with s-25(OH)D₃ ≤50 nmol/L (odds ratio: 0.41; 95% confidence interval, 0.18-0.95; P = 0.037). Non-sun versus sun vacations were associated with s-25(OH)D₃ ≤75 nmol/L (odds ratio: 5.33; 95% confidence interval, 1.93-14.77; P = 0.001).

CONCLUSIONS

The majority of the preschool children (81%) had s-25(OH)D₃ >50 nmol/L. Children with overweight status had an increased risk of s-25(OH)D₃ ≤50 nmol/L, and children who had not been on sun vacations were at a greater risk of s-25(OH)D₃ ≤75 nmol/L.

Dietary Patterns in New Zealand Women: Evaluating Differences in Body Composition and Metabolic Biomarkers

The combinations of food consumed together (dietary patterns) may have a greater influence on health than nutrients or food groups consumed independently. This study investigated the relationship between dietary patterns, body composition and metabolic biomarkers of premenopausal New Zealand women from three ethnic groups. In total, 408 New Zealand European, Māori and Pacific women aged 16-45 years participated in the Women's EXPLORE (EXamining Predictors Linking Obesity Related Elements) study. Participants completed a 220-item food frequency questionnaire. Several body composition parameters and metabolic biomarkers were measured. Dietary patterns were extracted by principal component analysis and dietary pattern scores were categorised into tertiles to assess links with other measured parameters. Women with higher scores for the 'refined and processed' pattern were younger, had higher body mass index, total body fat, plasma leptin and plasma insulin (p < 0.001), and lower plasma ghrelin levels (p < 0.05) than women with lower scores. In addition, more Māori (51%) and Pacific (68%) women followed the 'refined and processed' pattern, while more New Zealand European women (40%) followed the 'sweet and savoury snacking' pattern. These data show that dietary pattern analysis is a useful tool to assess links between diet and metabolic health. It further reveals interesting ethnic group-specific differences in dietary pattern use.

Extra-Skeletal Effects of Vitamin D

The vitamin D receptor is expressed in multiple cells of the body (other than osteoblasts), including beta cells and cells involved in immune modulation (such as mononuclear cells, and activated T and B lymphocytes), and most organs in the body including the brain, heart, skin, gonads, prostate, breast, and gut. Consequently, the extra-skeletal impact of vitamin D deficiency has been an active area of research. While epidemiological and case-control studies have often suggested a link between vitamin D deficiency and conditions such as type 1 and type 2 diabetes, connective tissue disorders, inflammatory bowel disorders, chronic hepatitis, food allergies, asthma and respiratory infections, and cancer, interventional studies for the most part have failed to confirm a causative link. This review examines available evidence to date for the extra-skeletal effects of vitamin D deficiency, with a focus on randomized controlled trials and meta-analyses.

Obesity and hypovitaminosis D: causality or casualty?

Epidemiological studies reported that vitamin D deficiency represents an increasingly widespread phenomenon in various populations. Vitamin D deficiency is considered a clinical syndrome determined by low circulating levels of 25-hydroxyvitamin D (25(OH)D), which is the biologically-inactive intermediate and represents the predominant circulating form. Different mechanisms have been hypothesized to explain the association between hypovitaminosis D and obesity, including lower dietary intake of vitamin D, lesser skin exposure to sunlight, due to less outdoor physical activity, decreased intestinal absorption, impaired hydroxylation in adipose tissue and 25(OH)D accumulation in fat. However, several studies speculated that vitamin D deficiency itself could cause obesity or prevent weight loss. The fat-solubility of vitamin D leads to the hypothesis that a sequestration process occurs in body fat depots, resulting in a lower bioavailability in the obese state. After investigating the clinical aspects of vitamin D deficiency and the proposed mechanisms for low 25(OH)D in obesity, in this manuscript we discuss the possible role of vitamin D replacement treatment, with different formulations, to restore normal levels in individuals affected by obesity, and evaluate potential positive effects on obesity itself and its metabolic consequences. Food-based prevention strategies for enhancement of vitamin D status and, therefore, lowering skeletal and extra-skeletal diseases risk have been widely proposed in the past decades; however pharmacological supplementation, namely cholecalciferol and calcifediol, is required in the treatment of vitamin D insufficiency and its comorbidities. In individuals affected by obesity, high doses of vitamin D are required to normalize serum vitamin D levels, but the different liposolubility of different supplements should be taken into account. Although the results are inconsistent, some studies reported that vitamin D supplementation may have some beneficial effects in people with obesity.

The effect of chronic oral vitamin D supplementation on adiposity and insulin secretion in hypothalamic obese rats

Reduced plasma vitamin D (VD) levels may contribute to excessive white adipose tissue, insulin resistance (IR) and dyslipidaemia. We evaluated the effect of chronic oral VD supplementation on adiposity and insulin secretion in monosodium glutamate (MSG)-treated rats. During their first 5 d of life, male neonate rats received subcutaneous injections of MSG (4 g/kg), while the control (CON) group received saline solution. After weaning, groups were randomly distributed into VD supplemented (12 µg/kg; three times/week) and non-supplemented (NS) rats, forming four experimental groups (n 15 rats/group): CON-NS, CON-VD, MSG-NS and MSG-VD. At 76 d of life, rats were submitted to an oral glucose tolerance test (OGTT; 2 g/kg), and at 86 d, obesity, IR and plasma metabolic parameters were evaluated. Pancreatic islets were isolated for glucose-induced insulin secretion (GIIS), cholinergic insulinotropic response and muscarinic 3 receptor (M3R), protein kinase C (PKC) and protein kinase A (PKA) expressions. Pancreas was submitted to histological analyses. VD supplementation decreased hyperinsulinaemia (86 %), hypertriacylglycerolaemia (50 %) and restored insulin sensibility (89 %) in MSG-VD rats, without modifying adiposity, OGTT or GIIS, compared with the MSG-NS group. The cholinergic action was reduced (57 %) in islets from MSG-VD rats, without any change in M3R, PKA or PKC expression. In conclusion, chronic oral VD supplementation of MSG-obese rats was able to prevent hyperinsulinaemia and IR, improving triacylglycerolaemia without modifying adiposity. A reduced cholinergic pancreatic effect, in response to VD, could be involved in the normalisation of plasma insulin levels, an event that appears to be independent of M3R and its downstream pathways.

Vitamin D Status, Calcium Intake and Risk of Developing Type 2 Diabetes: An Unresolved Issue

The relationship between vitamin D status, calcium intake and the risk of developing type 2 diabetes (T2D) is a topic of growing interest. One of the most interesting non-skeletal functions of vitamin D is its potential role in glucose homeostasis. This possible association is related to the secretion of insulin by pancreatic beta cells, insulin resistance in different tissues and its influence on systemic inflammation. However, despite multiple observational studies and several meta-analyses that have shown a positive association between circulating 25-hydroxyvitamin D concentrations and the risk of T2D, no randomized clinical trials supplementing with different doses of vitamin D have confirmed this hypothesis definitively. An important question is the identification of what 25-hydroxyvitamin D levels are necessary to influence glycemic homeostasis and the risk of developing T2D. These values of vitamin D can be significantly higher than vitamin D levels required for bone health, but the currently available data do not allow us to answer this question adequately. Furthermore, a large number of observational studies show that dairy consumption is linked to a lower risk of T2D, but the components responsible for this relationship are not well established. Therefore, the importance of calcium intake in the risk of developing T2D has not yet been established. Although there is a biological plausibility linking the status of vitamin D and calcium intake with the risk of T2D, well-designed randomized clinical trials are necessary to answer this important question.

Factors Affecting Vitamin D Status in Infants

Vitamin D is critical to children's skeletal development and health. Despite this, the factors which determine vitamin D concentrations during infancy remain incompletely understood. This article reviews the literature assessing the factors which can affect vitamin D status in infancy, including antenatal and postnatal vitamin D supplementation. Observational data supports that dietary intake of vitamin D, UV exposure, and geographic factors contribute significantly to infants' vitamin D status, but the relationship is unclear regarding genetic variation, ethnicity, and maternal vitamin D status. Randomised controlled trials have compared higher versus lower doses of infant vitamin D supplementation, but no studies have compared infant vitamin D supplementation to placebo and eliminated external sources of vitamin D to fully quantify its effect on vitamin D status. Knowledge gaps remain regarding the factors associated with optimal vitamin D concentrations in infants-including key factors such as ethnicity and genetic variation-and further studies are needed.

The Liver in Children With Metabolic Syndrome

Non-alcoholic fatty liver disease (NAFLD) is recognized as an emerging health risk in obese children and adolescents. NAFLD represents a wide spectrum of liver conditions, ranging from asymptomatic steatosis to steatohepatitis. The growing prevalence of fatty liver disease in children is associated with an increased risk of metabolic and cardiovascular complications. NAFLD is considered the hepatic manifestation of Metabolic Syndrome (MetS) and several lines of evidence have reported that children with NAFLD present one or more features of MetS. The pathogenetic mechanisms explaining the interrelationships between fatty liver disease and MetS are not clearly understood. Altough central obesity and insulin resistance seem to represent the core of the pathophysiology in both diseases, genetic susceptibility and enviromental triggers are emerging as crucial components promoting the development of NAFLD and MetS in children. In the present review we have identified and summarizied studies discussing current pathogenetic data of the association between NAFLD and MetS in children.

Vitamin D Insufficiency in Overweight and Obese Children and Adolescents

Excessive body weight and obesity in childhood and adolescence are becoming more and more important unfavorable factors that entail extremely adverse consequences and require close attention of physicians of any specialty. Along with the high prevalence of obesity and metabolic syndrome in pediatric patients, children and adolescents in the majority of countries are diagnosed with vitamin D deficiency. Among the non-calcaemic effects of vitamin D, a significant role is played by its impact on the hormonal regulation of glucose metabolism and the synthesis of adipokines by fat tissue. The review presents literature data indicative of a close pathogenic relationship between vitamin D insufficiency and impaired tissue insulin sensitivity. It demonstrates the role of vitamin D insufficiency in immune reactions resulting in development of subclinical inflammation in fat tissue infiltrated with macrophages and lymphocytes. It also shows the role of adipokines, immune system cells and pro-inflammatory cytokines produced by them in the pathogenesis of obesity, as well as the function of vitamin D as an endocrine and paracrine regulator of the process of inflammation in adipose tissue. The relationships between the principal adipokines (leptin, adiponectin, resistin) are revealed in the presence of normal vitamin D content and in vitamin D deficiency. The carbohydrate and lipid metabolism parameters in overweight children and adolescents with vitamin D insufficiency are analyzed. A high prevalence of vitamin D insufficiency in overweight and obese children and adolescents (increasing along with the severity of obesity) is demonstrated. The review also presents the current recommendations for the correction of vitamin D insufficiency and underlines the need for higher cholecalciferol doses to achieve serum calcifediol targets in overweight and obese children and adolescents.

Effect of vitamin D supplementation along with weight loss diet on meta-inflammation and fat mass in obese subjects with vitamin D deficiency: A double-blind placebo-controlled randomized clinical trial

BACKGROUND & AIMS

Low serum 25-hydroxyvitamin D (25OHD) is common in obese people. Obesity is associated with a state of low-grade inflammation (meta-inflammation). There is an increasing evidence indicating that vitamin D has anti-adipogenic activity and immunoregulatory effect. This study aimed to assess the effect of vitamin D supplementation on meta-inflammation and fat mass in obese subjects with vitamin D deficiency.

MATERIALS AND METHODS

In this double-blind placebo-controlled randomized clinical trial, 44 obese subjects with vitamin D deficiency (25OHD < 50 nmol/L) were assigned into vitamin D (a weight reduction diet + bolus weekly dose of 50 000 IU vitamin D) or placebo group (weight reduction diet + edible paraffin weekly) for 12 weeks. Weight, fat mass and serum levels of 25OHD, calcium, parathyroid hormone (PTH), monocyte chemoattractant protein-1 (MCP-1), interleukin-1β (IL-1β) and Toll-like receptor 4 (TLR4) were assessed before and after the intervention.

RESULTS

Vitamin D supplementation resulted in significant increase of serum 25OHD level (P < 0.001), and significant decrease in PTH (P < 0.001), MCP-1 (P < 0.05), IL-1β (P < 0.05) and TLR-4 (P < 0.05); compared to the baseline values in vitamin D group. Weight, BMI and fat mass decreased in both groups (P < 0.05). Between the groups, there were significant decrease in weight, fat mass, serum MCP-1 and PTH concentrations and significant increase in serum 25OHD concentrations after intervention with vitamin D supplementation compared to placebo (P < 0.05).

CONCLUSIONS

Improvement in vitamin D status in obese subjects with vitamin D deficiency in combination with weight loss diet resulted in weight, fat mass and MCP-1 decrease. Weight loss and vitamin D supplementation may act synergistically to reduce levels of meta-inflammation.

Determinants of Vitamin D deficiency in asymptomatic healthy young medical students

Objective:

The study aimed to determine vitamin D status and frequency of its determinants related to diet, clothing, lifestyle and exposure to sunlight among young healthy medical students living in Karachi, Pakistan.

Methods:

This cross sectional study included responses gathered on questionnaire from medical students of Karachi Medical &Dental College from 4^th of August 2017 till 30^th April 2018. All the participants were healthy young adult’s year of age who gave written informed consent to participate in the study. Questions regarding demographics, sun exposure, diet, clothing, living patterns and any symptoms like pain or body aches were recorded. Serum 25 (OH) vitamin D3, calcium and phosphorus levels were measured through laboratory examination. For serum 25OHD, the cutoff values ≤ 20ng /ml, ≥ 21-29ng /ml, and ≥ 30ng/ml were defined as deficiency, insufficiency, and sufficiency respectively.

Results:

Total number of medical students enrolled in the study was 221.Among total participants 191 (86.43%) were females and 30 (13.57%) were males. Mean ± SD age was almost similar (23.00 ± 2.56 vs. 23.03 ± 2.05). Majority of the females 115 (60.2%) had BMI within normal range, and were predominantly single 164 (85.9%). Vitamin D deficiency was found in 197 (89.14%), insufficiency in 16 (7.24%), and only 8 (3.62%) had sufficient levels. Determinant factors reported by deficient group (n=197); fabric color (dark mix) 87.3%, fabric material (synthetic + mix) 48.7%, full length of sleeves by 45.7%, exposure to sun only on hands and face during outdoors was reported by 64.5%, milk up to 250 cc was consumed by 77.2%, one egg per day in diet was taken by 56.9% and intake of cod liver oil was less common in only 27.4%.

Conclusion:

Deficiency of vitamin D is common among healthy young adults particularly females which emphasize need to add vitamin D supplements in their routine diet.

Fetuin B links vitamin D deficiency and pediatric obesity: Direct negative regulation by vitamin D

Vitamin D (VD) deficiency (VDD) correlates to obesity, with VD a recognized mediator of metabolic diseases. From a previous proteomic study identifying adiponectin as a link between VDD and pediatric obesity, herein we analysed another protein (SSP2301) increased with VDD. A focused 2D-electrophoretic analysis identified 4 corresponding plasma proteins, with one predicted to be fetuin B (FETUB). FETUB was studied due to its emerging role in metabolic diseases and cytogenetic location (3q27.3) with adiponectin. Results were confirmed in obese children, where plasma FETUB was higher with VDD. A direct effect by 1α,25-(OH)2D3 on hepatocellular FETUB synthesis was observed, with a time and dose dependent reduction. Further, we demonstrated the VD-receptor (VDR) is key, with FETUB "released" with VDR silencing. Finally, VD supplementation (6weeks) to juvenile mice fed a standard diet, reduced plasma FETUB. Only at 22weeks did liver FETUB correspond to plasma FETUB, highlighting the contribution of other VD-responsive tissues. Overall, FETUB is a key protein linking VDD to pediatric obesity. With an emerging role in metabolic diseases, we demonstrate that VD/VDR directly regulate FETUB.

Nutritional Health Considerations for Persons with Spinal Cord Injury

Chronic spinal cord injury (SCI) often results in morbidity and mortality due to all-cause cardiovascular disease (CVD) and comorbid endocrine disorders. Several component risk factors for CVD, described as the cardiometabolic syndrome (CMS), are prevalent in SCI, with the individual risks of obesity and insulin resistance known to advance the disease prognosis to a greater extent than other established risks. Notably, adiposity and insulin resistance are attributed in large part to a commonly observed maladaptive dietary/nutritional profile. Although there are no evidence-based nutritional guidelines to address the CMS risk in SCI, contemporary treatment strategies advocate more comprehensive lifestyle management that includes sustained nutritional guidance as a necessary component for overall health management. This monograph describes factors in SCI that contribute to CMS risks, the current nutritional profile and its contribution to CMS risks, and effective treatment strategies including the adaptability of the Diabetes Prevention Program (DPP) to SCI. Establishing appropriate nutritional guidelines and recommendations will play an important role in addressing the CMS risks in SCI and preserving optimal long-term health.

Age and gender differences in the prevalence and correlates of vitamin D deficiency

Younger adults and males had a higher prevalence of vitamin D deficiency compared to older participants and females. Low intake of milk, central obesity, and lack of use of vitamin D supplements were associated with vitamin D deficiency, highlighting potentially important avenues for preventive intervention.

BACKGROUND

Vitamin D deficiency is a public health concern. This study's objective was to measure the prevalence of vitamin D deficiency and determine its correlates among Saudi adults in Riyadh, Saudi Arabia.

METHODS

A cross-sectional study was conducted with 2835 Saudi males and females aged 30-75 years in 18 different primary health care centers (PHCC) in Riyadh. Detailed interviews on sociodemographic and lifestyle factors and anthropometric measurements were conducted. Serum calcium, phosphorus, parathyroid, alkaline phosphatase, and 25(OH) vitamin D were measured. Multiple logistic regression analyses were conducted.

RESULTS

The mean age (SD) of male and female participants was 43.0 (± 11.7) and 42.8 (± 10.3) years, respectively. Serum 25(OH) vitamin D assays for participants revealed that 72.0% (n = 695) of males and 64.0% (n = 1191) of females had levels < 50 nmol/L (deficiency), whereas 17.3% (n = 166) and 19.4% (n = 362), respectively, had levels of 50-75 nmol/L (insufficiency). Multivariate analyses for males revealed that lack of use of vitamin D supplements [adjusted odds ratio (aOR) = 4.0, 95% CI 1.7, 9.4], younger age [30-40 years aOR = 3.6, 95% CI 1.7, 7.3 and 41-50 years aOR = 4.2, 95% CI 2.0, 8.8], low milk intake [aOR = 1.7, 95% CI 1.0, 2.8], consumption of cola drinks [aOR = 2.0, 95% CI 1.1, 3.9], and central obesity [aOR = 1.8, 95% CI 1.0, 3.4] were associated with low vitamin D. In females, lack of use of vitamin D supplements [aOR = 3.7, 95% CI 2.8, 4.9], younger age [30-40 years aOR = 3.4, 95% CI 2.0, 5.8 and 41-50 years aOR = 2.8, 95% CI 1.6, 4.7], central obesity [aOR = 1.4, 95% CI 1.0, 2.2], and seasonal variation [aOR = 1.6, 95% CI 1.3, 2.1] had higher odds for vitamin D deficiency. Significantly lower levels were observed for men than women for mean serum 25(OH) vitamin D [42.6 (± 24.1) vs. 46.8 (± 30.5)], parathyroid hormone [5.3 (± 2.9) vs. 5.9 (± 2.7)], and phosphorus [1.1 (± 0.2) vs. 1.2 (± 0.2)], respectively; alkaline phosphatase levels [106 (± 32.8) vs. 99 (± 27.8)] [p < 0.01] were significantly higher in males than females.

CONCLUSION

Vitamin D deficiency was highly prevalent, particularly among young adults and those with central obesity. Proper fortification policy, health education, and regular screening PHCCs may help prevent and treat vitamin D deficiency.

Effect of Vitamin D Supplementation on Obesity-Induced Insulin Resistance: A Double-Blind, Randomized, Placebo-Controlled Trial

OBJECTIVE

The aim was to investigate whether vitamin D supplementation, combined with a hypocaloric diet, could have an independent effect on insulin sensitivity in subjects with both overweight and hypovitaminosis D. Changes from baseline in anthropometric parameters, body composition, glucose tolerance, and insulin secretion were considered as secondary outcomes.

METHODS

Eighteen volunteers who were nondiabetic and vitamin D deficient and had BMI > 25 kg/m² were randomized (1:1) in a double-blind manner to a hypocaloric diet + either oral cholecalciferol at 25,000 IU/wk or placebo for 3 months. Hyperinsulinemic-euglycemic clamp to measure insulin sensitivity was performed at baseline and after intervention.

RESULTS

Body weight in both groups decreased significantly (-7.5% in the vitamin D group and -10% in the placebo group; P < 0.05 for both), with no between-group differences. Serum 25-hydroxyvitamin D levels in the vitamin D group increased considerably (from 36.7 ± 13.2 nmol/L to 74.8 ± 18.7 nmol/L; P < 0.001). Insulin sensitivity in the vitamin D group improved (from 4.6 ± 2.0 to 6.9 ± 3.3 mg·kg^-1 ·min^-1 ; P < 0.001), whereas no changes were observed in the placebo group (from 4.9 ± 1.1 to 5.1 ± 0.3 mg·kg^-1 ·min^-1 ; P = 0.84).

CONCLUSIONS

Cholecalciferol supplementation, combined with a weight loss program, significantly improves insulin sensitivity in healthy subjects with obesity and might represent a personalized approach for insulin-resistant subjects with obesity.