Vitamin D status, adiposity, and lipids in black American and Caucasian children

Vitamin D and Dyslipidemia: Is There Really a Link? A Narrative Review

Nowadays, the interest in the extraskeletal effects of vitamin D is growing. In the literature, its several possible actions have been confirmed. Vitamin D seems to have a regulatory role in many different fields-inflammation, immunity, and the endocrine system-and many studies would demonstrate a possible correlation between vitamin D and cardiovascular disease. In this paper, we deepened the relationship between vitamin D and dyslipidemia by reviewing the available literature. The results are not entirely clear-cut: on the one hand, numerous observational studies suggest a link between higher serum vitamin D levels and a beneficial lipid profile, while on the other hand, interventional studies do not demonstrate a significant effect. Understanding the possible relationship between vitamin D and dyslipidemia may represent a turning point: another link between vitamin D and the cardiovascular system.

Poor vitamin D status was associated with increased appendicular fat deposition in US Adults: Data from 2011-2018 National Health and Nutrition Examination Survey

The aim of the study was to explore the relationship between serum 25-hydroxyvitamin D [25(OH)D] concentrations and regional body fat deposition in 2011-2018 National Health and Nutrition Examination Survey participants aged 18 to 59 years. We hypothesized that serum 25(OH)D concentrations were negatively associated with total, appendicular, and truncal fat deposition. Serum 25(OH)D concentration was categorized into sufficient (≥75.0 nM), insufficient (50.0-74.9 nM), and deficient (<50.0 nM) groups. Fat mass (FM) was measured by dual-energy X-ray absorptiometry, and FM index (FMI) was calculated by dividing FM (kg) with height2 (m2). Multivariant linear regression and Granger causal analysis were performed to assess the causal relationship between vitamin D status and regional FMIs. Overall serum 25(OH)D concentrations were negatively associated with total (β = -0.029, standard error [SE] = 0.002), trunk (β = -0.015, SE = 0.001), arms (β = -0.004, SE = 3.09 × 10-4), and legs (β = -0.010, SE = 0.001) FMIs in all participants (P < .001, respectively); however, after stratified by vitamin D status and BMI, the negative associations were only observed in individuals with vitamin D deficiency and obesity. The causal analysis indicated that serum 25(OH)D concentrations may causally reduce the arms (F = 4.917, probability [P] = 0.007), legs (F = 5.783, P = 0.003), and total (F = 3.202, P = 0.041) FMIs except for trunk FMI but not vice versa. In conclusion, poor vitamin D status was associated with increased total and appendicular body fat deposition in US adults, particularly in participants with obesity.

Relationship Between Vitamin D Deficiency and Non-alcoholic Fatty Liver Disease: A Cross-Sectional Study From a Tertiary Care Center in Northern India

Background Vitamin D levels are strongly associated with myocardial infarction, coronary artery disease, heart dysfunction, and even mortality. Non-alcoholic fatty liver disease (NAFLD) is a prevalent hepatic illness whose incidence has grown dramatically over the past several decades. Methodology This observational, cross-sectional study was conducted over 1.5 years (January 2019 to June 2020) at the Department of General Medicine of a tertiary care hospital in northern India on 100 adult patients with NAFLD admitted to the emergency ward, intensive care unit, and medical ward. Results In our study, of the 100 patients, 45.0%, 16.0%, and 39.0% of patients exhibited vitamin D deficiency, insufficiency, and sufficiency, respectively. Vitamin D deficiency was the highest among those aged 41-50 (54.2%) and lowest among those aged 30-40 (29.0%). We observed that vitamin D deficiency was less prevalent in people with a normal body mass index (39.1%) than in those who were overweight (91.7%). There was a significant (p < 0.05) association between the severity of vitamin D deficiency and the presence of hepatomegaly, splenomegaly, and ascites. Overall, the incidence of fatty liver was 49% among patients. There was a significant (p = 0.0001) correlation between fatty liver and serum vitamin D levels. The association between the proportion of patients with fatty liver and the degree of vitamin D deficiency was found to be significant (p = 0.04). The relationship between the distribution of patients according to insulin resistance and the degree of vitamin D deficiency was also statistically significant (p < 0.001). Conclusions Vitamin D deficiency is associated with an increased risk of NAFLD, as well as with the severity of NAFLD.

Multicentric Italian case-control study on 25OH vitamin D levels in children and adolescents with Prader-Willi syndrome

PURPOSE

25OHD levels in patients with Prader-Willi Syndrome (PWS), the most frequent cause of genetic obesity with a peculiar fat mass distribution, are still debated. Insulin resistance (IR), Body Mass Index-SDS (BMI-SDS), Growth Hormone Therapy (GHT), and puberty onset seem to interact with 25OHD levels. The objectives of the study are: (1) To analyze 25OHD levels in pediatric PWS patients in comparison with a control group (CNT) (2) To evaluate a possible correlation between BMI-SDS, HOMA-IR, puberty, GHT, and 25OHD levels.

METHODS

This is a retrospective case-control, multicenter study. Data were collected among 8 different Italian Hospitals (outpatient clinics), over a period of four years (2016-2020). We included 192 genetically confirmed PWS and 192 CNT patients, aged 3-18 years, matched 1:1 for age, gender, BMI-SDS, Tanner stage, sun exposure, and month of recruitment.

RESULTS

No statistically significant differences in 25OHD levels were observed between the PWS population and the CNT (PWS 24.0 ng/mL vs CNT 22.5 ng/mL, p > 0.05), OR = 0.89 (95% CI 0.58-1.35). We observed a slight, although non-significant, reduction in 25OHD levels comparing NW and OB populations. HOMA-IR, puberty onset, genotype and GHT (previous or ongoing) did not show statistically significant correlation with 25OHD levels.

CONCLUSIONS

Our findings could be useful for clinicians to optimize the therapeutic management as well as to increase awareness of PWS.

Effect of vitamin D metabolites on bone histomorphometry in healthy black and white women: An attempt to unravel the so-called vitamin D paradox in blacks

An apparent vitamin D paradox, characterized by lower serum 25-hydroxyvitamin D (25(OH)D) levels and higher bone mineral density, is present in black population. In contrast, blacks have higher serum 1,25-dihydroxyvitamin D (1,25(OH)₂D) levels. The effect of 1,25(OH)₂D on the skeleton is not fully understood. We examined serum 25(OH)D, 1,25(OH)₂D and bone histomorphometry in 50 black and white women (25 each) matched for age, menstrual status, and BMI. Histomorphometric indices related to bone structure, remodeling and mineralization were measured in cancellous bone in iliac bone biopsies. Data analyses led to the following results: 1) serum 25(OH)D was significantly lower and 1,25(OH)₂D was significantly higher in black than in white women, but neither blacks nor whites revealed significant correlation between these two vitamin D metabolites. 2) there was no significant difference in PTH levels between blacks and whites. 3) except for greater trabecular thickness (Tb.Th) in blacks, there were no significant differences in other histomorphometric variables between the two ethnic groups. 4) osteoid surface (OS/BS), unlabeled osteoid surface (ulOS/BS), and osteoblast surface (ObS/BS) significantly correlated with serum 1,25(OH)₂D levels. We conclude that lower serum 25(OH)D levels in blacks do not impair bone structure and remodeling, nor decrease bone mineralization. Higher serum 1,25(OH)₂D levels in blacks may help preserve bone mass by stimulating bone formation via increasing osteoblast number and function, but moderately inhibit terminal bone mineralization as shown by higher ulOS/BS.

Association between serum vitamin D levels and visceral adipose tissue among adolescents: a cross-sectional observational study in NHANES 2011–2015

Background

In recent years, obesity and vitamin D deficiency are more prevalent among adolescents. Improving our knowledge of the link between vitamin D and visceral adipose tissue (VAT) is essential for the health of adolescents. This study aimed to examine the connection between serum vitamin D levels and VAT mass among adolescents participating in the United States.

Methods

This is a cross-sectional study that used data from the 2011 to 2015 National Health and Nutrition Examination Survey (NHANES). The connection between serum vitamin D levels and VAT was investigated using weighted multiple linear regression models. Potential nonlinear relationships were explored using smooth curve fitting.

Results

The analysis included 3171 adolescents aged 12–19 years. Vitamin D levels were shown to be inversely linked with VAT in the full-adjusted model (β = − 0.34, 95% CI: − 0.49 to − 0.19). When stratified analyses by gender, this negative relationship persisted in the girls’ group (β = − 0.39, 95% CI: − 0.60 to − 0.19), but not in the boys’ group (β = − 0.06, 95% CI: − 0.25 to 0.13). When stratified analysis by race, this negative relationship persisted in the Mexican American group (β = − 0.61, 95% CI: − 1.03 to − 0.19), and the non-Hispanic White group (β = − 0.27, 95% CI: − 0.54 to − 0.01), but not in the other groups.

Conclusions

Our findings confirmed that serum vitamin D levels negatively correlated with VAT among adolescents in the United State, especially in girls, the Mexican American and non-Hispanic White. Further research is needed to determine whether increasing serum vitamin D levels decrease VAT among adolescents.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03688-2.

Prevalence, trend, and predictor analyses of vitamin D deficiency in the US population, 2001-2018

Background

The National Health and Nutrition Examination Surveys (NHANES) collect and release data to the public every 2 years. The latest NHANES study on the vitamin D status of Americans was based on data from 2001 to 2014, and the latest data (2015–2016 and 2017–2018) have not been studied yet. Thus, we extracted all the available data from NHANES (2001–2018), aiming to analyze the prevalence and trends of vitamin D deficiency (VDD) in the US population to bridge the research gap.

Methods

According to previous studies and nutritional guidelines for vitamin D, severe VDD was defined as serum 25(OH)D levels of <25 nmol/L, moderate deficiency as 25–50 nmol/L, insufficiency as 50–75 nmol/L, and sufficiency as >75 nmol/L. We comprehensively estimated the prevalence of serum 25(OH)D levels of <25, 25–50, 50–75, and >75 nmol/L in Americans and described trends in vitamin D status from 2001 to 2018. Weighted multivariate linear regression models were used to explore the predictors of VDD. All analyses and the data were adjusted for the complex sampling design of NHANES using Mobile Examination Center (MEC) weights.

Results

Based on the most recent data of 71,685 participants, our study showed that the weighted prevalence of severe and moderate VDD was 2.6% and 22.0%, and the prevalence of vitamin D insufficiency (VDI) and sufficiency was 40.9% and 34.5%. The prevalence of severe and moderate VDD was higher in women, non-Hispanic black Americans, people aged 20–29 years, and during the season of winter. From 2001 to 2018, we found a slight linear decrease in the prevalence of moderate VDD (coefficient = −0.847; P = 0.009) and VDI (coefficient = −0.810; P = 0.014). We also found a slight linear increase in vitamin D sufficient (coefficient = 1.693; P = 0.004). However, no trend change was observed in severe VDD (coefficient = −0.037; P = 0.698). Age, sex, ethnicity, season, sun-protective behaviors, lower BMI, lower socioeconomic status (SES), drinking, and lower milk consumption were predictors of severe VDD.

Conclusion

Vitamin D deficiency is still prevalent in the United States, especially in non-Hispanic black Americans, women, individuals aged 20–29, and during winter. Therefore, individuals, healthcare providers, and policymakers should take public health measures to develop and implement prevention strategies to deal with VDD.

PCOS Physiopathology and Vitamin D Deficiency: Biological Insights and Perspectives for Treatment

Recent literature has stressed the importance of vitamin D (VD) in polycystic ovary syndrome (PCOS). Women with PCOS are deficient in VD, particularly those with a higher weight. Hypovitaminosis is a risk factor for glucose intolerance, and reduced levels of VD is associated with insulin resistance and increased diabetes risk. Since women with PCOS and hirsutism seem to have lower levels of VD than women with PCOS without hirsutism, a correlation between VD deficiency and hyperandrogenism may be suggested. Interestingly, VD is crucial for many human physiological functions, including to counteract inflammation and oxidative stress. Some studies evaluated effects of VD supplementation on glucose homeostasis variables, hormonal status, lipid concentrations, and biomarkers of inflammation and oxidative stress among VD-deficient women. Moreover, VD has been shown to play a role in egg quality and fertility. This review aims to show the relationship between VD and the endocrine and metabolic profile of PCOS patients, as well as its implications for their fertility. The supplement of VD to the common therapy can lead to an improvement of the insulin resistance and lipid metabolism, a reduction of circulating androgens, as well as a better response to the induction of ovulation in PCOS women.

Associations between serum 25-hydroxyvitamin D, body mass index and body fat composition among Emirati population: Results from the UAE healthy future study

INTRODUCTION

Vitamin D deficiency and insufficiency are highly prevalent among several populations across the globe. Numerous studies have shown a significant correlation between body-mass-index (BMI) and Vitamin D status, however, some results differed according to ethnicity. Despite the abundance of sunshine throughout the year, vitamin D deficiency is prominent in the United Arab Emirates (UAE). In this study, we analyzed the UAE Healthy Future Study (UAEHFS) pilot data to investigate the association between serum 25-hydroxyvitamin D (25(OH)D) and % body fat (BF) composition as well as BMI.

MATERIAL AND METHODS

Data from a total of 399 Emirati men and women aged ≥ 18 years were analyzed. Serum 25(OH)D and standard measures of weight and height were included in the analyses. Vitamin D deficiency was defined as serum 25(OH)D concentration<20 ng/ml. Multivariate quantile regression models were performed to explore the relationship between serum 25(OH)D levels and % BF composition and BMI correspondingly.

RESULTS

There were 281 (70.4%) males and 118 (29.6%) females included in this study. More than half of the study participants had vitamin D insufficiency (52.4%), and nearly a third had vitamin D deficiency (30.3%); while only 17.3% had optimal levels. A statistically significant negative association between serum 25(OH) D levels and % BF composition was observed at intermediate percentiles while a statistically significant negative association between serum 25(OH)D and BMI was only observed at the median (50th percentile).

CONCLUSION

The study findings support the association between low serum 25(OH) D levels (low vitamin D status) and high % BF composition and high BMI among adult Emiratis. Further longitudinal data from the prospective UAEHFS could better elucidate the relationship between serum 25(OH) D levels, % BF composition, and BMI in the context of various health outcomes among this population.

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

INTRODUCTION

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Musculoskeletal Health in Active Ambulatory Men with Cerebral Palsy and the Impact of Vitamin D

Purpose: (1) To determine the contribution of diet, time spent outdoors, and habitual physical activity (PA) on vitamin D status in men with cerebral palsy (CP) compared to physical activity matched controls (TDC) without neurological impairment; (2) to determine the role of vitamin D on musculoskeletal health, morphology, and function in men with CP compared to TDC. Materials and methods: A cross-sectional comparison study where 24 active, ambulant men with CP aged 21.0 ± 1.4 years (Gross Motor Function Classification Score (I–II) and 24 healthy TDC aged 25.3 ± 3.1 years completed in vivo assessment of musculoskeletal health, including: vastus lateralis anatomical cross-sectional area (VL ACSA), isometric knee extension maximal voluntary contraction (KE iMVC), 10 m sprint, vertical jumps (VJ), and radius and tibia bone ultrasound (US) T_us and Z_us scores. Assessments of vitamin D status through venous samples of serum 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone, dietary vitamin D intake from food diary, and total sun exposure via questionnaire were also taken. Results: Men with CP had 40.5% weaker KE iMVC, 23.7% smaller VL ACSA, 22.2% lower VJ, 14.6% lower KE iMVC/VL ACSA ratio, 22.4% lower KE iMVC/body mass (BM) ratio, and 25.1% lower KE iMVC/lean body mass (LBM) ratio (all p < 0.05). Radius T_us and Z_us scores were 1.75 and 1.57 standard deviations lower than TDC, respectively (p < 0.05), whereas neither tibia T_us nor Z_us scores showed any difference compared to TDC (p > 0.05). The 25(OH)D was not different between groups, and 90.9% of men with CP and 91.7% of TDC had low 25(OH)D levels when compared to current UK recommendations. The 25(OH)D was positively associated with KE iMVC/LBM ratio in men with CP (r = 0.500, p = 0.020) but not in TDC (r = 0.281, p = 0.104). Conclusion: Musculoskeletal outcomes in men with CP were lower than TDC, and despite there being no difference in levels of 25(OH)D between the groups, 25 (OH)D was associated with strength (KE iMVC/LBM) in the CP group but not TDC. The findings suggest that vitamin D deficiency can accentuate some of the condition-specific impairments to musculoskeletal outcomes.

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.

Early-Life Factors Are Associated with Vitamin D Status in Early and Mid-Childhood and May Differ between White and Black Children

BACKGROUND

Suboptimal vitamin D (VitD) status has been associated with poor bone health and other adverse health outcomes and is common among children. Various early-life factors are associated with child VitD, yet few studies have examined multiple factors simultaneously in a single study population.

OBJECTIVES

We aimed to characterize relations of early-life factors with plasma 25-hydroxyvitamin D [25(OH)D] concentrations in early and mid-childhood, and to explore potential differences in these associations between white and black children.

METHODS

We identified associations of various early-life factors with 25(OH)D concentrations in early and mid-childhood among 961 children in Project Viva using linear regression models. All variables associated with 25(OH)D were included together in final multivariable models at each outcome time point: 1 in the overall sample and additional models for children whose mothers identified them as being white or black.

RESULTS

Overall mean ± SD 25(OH)D concentrations were 86 ± 29 nmol/L in early childhood and 68 ± 21 nmol/L in mid-childhood. After accounting for other predictors, children who took VitD supplements (compared with those who did not) had 25(OH)D concentrations 5.6 nmol/L (95% CI: 2.0, 9.2 nmol/L) higher in early childhood and 8.2 nmol/L (95% CI: 4.8, 11.6 nmol/L) higher in mid-childhood. Other factors consistently associated with higher 25(OH)D were blood collection in summer or fall, white race, nonfall birth season, prenatal exposure to higher 25(OH)D, and higher dietary intake of VitD. Greater waist circumference was associated with lower 25(OH)D in early childhood (β: -3.8; 95% CI: -7.4, -0.2 per 1-SD increase) among black children only.

CONCLUSIONS

Our findings may help clinicians better target children at risk of lower 25(OH)D for screening and/or intervention and may inform research focused on associations of 25(OH)D with different exposures and outcomes or causal effects of early-life factors on later VitD status.This trial was registered at clinicaltrials.gov as NCT02820402.

Prevalence and predictors of vitamin D deficiency in a nationally representative sample of Australian adolescents and young adults

Background/Objectives

Vitamin D deficiency is a public health concern worldwide. Maintaining vitamin D sufficiency during growth periods is essential. We aimed to determine the prevalence and predictors of vitamin D deficiency in Australian adolescents and young adults.

Subject/Methods

We used data from adolescents (12–17 years, n = 692) and young adults (18–24 years, n = 400) who participated in the nationally representative 2011–2013 Australian Health Survey. Serum 25-hydroxyvitamin D concentrations were measured using a method certified to international standards, with prevalence reported for <50 (vitamin D deficiency), 50–<75, ≥75 and >125 nmol/L. Independent predictors of vitamin D deficiency were determined using a survey-weighted Poisson regression model.

Results

Overall, 17% of adolescents and 32% of young adults were vitamin D deficient. In models adjusted for sex, age, region of birth, socioeconomic status, BMI and season (and education, smoking status and physical activity in young adults only), the prevalence ratio (PR) for vitamin D deficiency was more than double in participants born outside Australia (adolescents: PR 2.46; 95% confidence interval (CI) = 1.59, 3.81; young adults: PR 2.12; 95% CI = 1.46, 3.07), and also varied by season (adolescents: spring vs summer PR 2.47; 95% CI = 1.22, 5.01 and winter vs summer PR 2.01; 95% CI = 1.03, 3.92; young adults: winter vs summer; PR 3.32; 95% CI = 1.69, 6.53). Other predictors of vitamin D deficiency were overweight compared with healthy weight (adolescents) and lower physical activity (young adults).

Conclusions

Strategies based on safe sun exposure and dietary approaches are needed to achieve and maintain adequate vitamin D status, particularly in young adults.

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.

An Evaluation of Serum 25-Hydroxy Vitamin D Levels in Patients with COVID-19 in New York City

AIM

Deterioration of patients from COVID-19 is associated with cytokine release syndrome attributed to an elevation in pro-inflammatory cytokines. Vitamin D reduces proinflammatory cytokines, and has the possibility of reducing complications from respiratory tract illnesses.

METHOD

This was a retrospective, observational, cohort study of patients with COVID-19 disease within a New York City Health System. Adult patients were included if they tested positive for SARS-CoV-2, and had a serum 25-hydroxy vitamin D level (25(OH)D) within the three previous months prior to their detected SARS-CoV-2 test. Patients were compared and evaluated based upon their 25(OH)D levels. The primary endpoints were hospitalization, need for oxygen support, and 90-day mortality.

RESULTS

437 COVID-19 patients were included [67 (IQR: 56-79) years] within this cohort. Deficient plasma 25(OH)D levels (<20 ng/ml) were associated with an increased likelihood of oxygen support [OR:2.23 (95% CI: 1.46-3.44, p = 0.0002)] from COVID-19. Deficient plasma 25(OH)D levels were not independently associated with 90-day mortality or risk of hospitalization. Hospitalization rates (98%), oxygen support (93%), and mortality rates (49%) were highest in patients who had 25(OH)D levels less than 10 ng/ml when compared to other 25(OH)D levels.

CONCLUSION

Serum 25-hydroxy vitamin D levels may affect the need for oxygen support therapy in patients with COVID-19.

The potential link between inherited G6PD deficiency, oxidative stress, and vitamin D deficiency and the racial inequities in mortality associated with COVID-19

There is a marked variation in mortality risk associated with COVID-19 infection in the general population. Low socioeconomic status and other social determinants have been discussed as possible causes for the higher burden in African American communities compared with white communities. Beyond the social determinants, the biochemical mechanism that predisposes individual subjects or communities to the development of excess and serious complications associated with COVID-19 infection is not clear. Virus infection triggers massive ROS production and oxidative damage. Glutathione (GSH) is essential and protects the body from the harmful effects of oxidative damage from excess reactive oxygen radicals. GSH is also required to maintain the VD-metabolism genes and circulating levels of 25-hydroxyvitamin D (25(OH)VD). Glucose-6-phosphate dehydrogenase (G6PD) is necessary to prevent the exhaustion and depletion of cellular GSH. X-linked genetic G6PD deficiency is common in the AA population and predominantly in males. Acquired deficiency of G6PD has been widely reported in subjects with conditions of obesity and diabetes. This suggests that individuals with G6PD deficiency are vulnerable to excess oxidative stress and at a higher risk for inadequacy or deficiency of 25(OH)VD, leaving the body unable to protect its 'oxidative immune-metabolic' physiological functions from the insults of COVID-19. An association between subclinical interstitial lung disease with 25(OH)VD deficiencies and GSH deficiencies has been previously reported. We hypothesize that the overproduction of ROS and excess oxidative damage is responsible for the impaired immunity, secretion of the cytokine storm, and onset of pulmonary dysfunction in response to the COVID-19 infection. The co-optimization of impaired glutathione redox status and excess 25(OH)VD deficiencies has the potential to reduce oxidative stress, boost immunity, and reduce the adverse clinical effects of COVID-19 infection in the AA population.

Can Vitamin D and L-Cysteine Co-Supplementation Reduce 25(OH)-Vitamin D Deficiency and the Mortality Associated with COVID-19 in African Americans?

Early reports indicate an association between the severity of the COVID-19 infection and the widespread 25-hydroxy vitamin D deficiency known to exist in populations around the world. Vitamin D deficiency is extremely common among African American (AA) communities, where the COVID-19 infection rate is three-fold higher, and the mortality rate nearly six-fold higher, compared with rates in predominantly white communities. COVID-19 infection primarily affects the lungs and airways. Previous reports have linked 25-hydroxy vitamin D deficiency with subclinical interstitial lung disease. AA are at risk for lower cellular glutathione (GSH) levels, and GSH deficiency epigenetically impairs VD biosynthesis pathway genes. Compared with vitamin D alone, co-supplementation of vitamin D and L-cysteine (a GSH precursor) showed a better efficacy in improving levels of GSH and VD-regulatory genes at the cellular/tissue level, increasing 25(OH) vitamin D levels, and reducing inflammation biomarkers in the blood in mice studies. We propose that randomized clinical trials are needed to examine the potential of co-supplementation with anti-inflammatory antioxidants, vitamin D and L-cysteine in correcting the 25(OH)VD deficiency and preventing the 'cytokine storm,' one of the most severe consequences of infection with COVID-19, thereby preventing the adverse clinical effects of COVID-19 infection in the vulnerable AA population.

The Association between Serum Levels of 25[OH]D, Body Weight Changes and Body Composition Indices in Patients with Heart Failure

We try to determine the association between weight changes (WC), both loss or gain, body composition indices (BCI) and serum levels of 25[OH]D during heart failure (HF). WC was determined in 412 patients (14.3% female, aged: 53.6 ± 10.0 years, NYHA class: 2.5 ± 0.8). Body fat, fat percentage and fat-free mass determined by dual energy X-rays absorptiometry (DEXA) and serum levels of 25[OH]D were analyzed. Logistic regression was used to calculate odds ratios for 25[OH]D insufficiency (<30 ng/mL) or deficiency (<20 ng/mL) by quintiles of WC, in comparison to weight-stable subgroup. The serum 25[OH]D was lower in weight loosing than weight stable subgroup. In fully adjusted models the risk of either insufficient or deficient 25[OH]D levels was independent of BCI and HF severity markers. The risk was elevated in higher weight loss subgroups but also in weight gain subgroup. In full adjustment, the odds for 25[OH]D deficiency in the top weight loss and weight gain subgroups were 3.30; 95%CI: 1.37–7.93, p = 0.008 and 2.41; 95%CI: 0.91–6.38, p = 0.08, respectively. The risk of 25[OH]D deficiency/insufficiency was also independently associated with potential UVB exposure, but not with nutritional status and BCI. Metabolic instability in HF was reflected by edema-free WC, but not nutritional status. BCI is independently associated with deficiency/insufficiency of serum 25[OH]D.

Effect of vitamin D3 supplementation on vascular and metabolic health of vitamin D-deficient overweight and obese children: a randomized clinical trial

BACKGROUND

Obese children are vulnerable to vitamin D deficiency and impaired cardiovascular health; vitamin D replenishment might improve their cardiovascular health.

OBJECTIVES

The aims were to determine, in vitamin D-deficient overweight and obese children, whether supplementation with vitamin D3 1000 or 2000 IU/d is more effective than 600 IU/d in improving arterial endothelial function, arterial stiffness, central and systemic blood pressure (BP), insulin sensitivity (1/fasting insulin concentration), fasting glucose concentration, and lipid profile and to explore whether downregulation of adipocytokines and markers of systemic inflammation underlies vitamin D effects.

METHODS

We conducted a randomized, double-masked, controlled clinical trial in 225 10- to 18-y-old eligible children. Change in endothelial function at 6 mo was the primary outcome.

RESULTS

Dose-response increases in serum 25-hydroxyvitamin D concentrations were significant and tolerated without developing hypercalcemia. Changes at 3 and 6 mo in endothelial function, arterial stiffness, systemic-systolic BP, lipids, and inflammatory markers did not differ between children receiving 1000 or 2000 IU vitamin D and children receiving 600 IU. Some secondary outcomes differed between groups. Compared with the 600-IU group, central-systolic, central-diastolic, and systemic-diastolic BP was lower at 6 mo in the 1000-IU group [-2.66 (95% CI: -5.27, -0.046), -3.57 (-5.97, -1.17), and -3.28 (-5.55, -1.00) mm Hg, respectively]; insulin sensitivity increased at 3 and 6 mo and fasting glucose concentration declined at 6 mo (-2.67; 95% CI: -4.88, -0.46 mg/dL) in the 2000-IU group.

CONCLUSIONS

Correction of vitamin D deficiency in overweight and obese children by vitamin D3 supplementation with 1000 or 2000 IU/d versus 600 IU/d did not affect measures of arterial endothelial function or stiffness, systemic inflammation, or lipid profile, but resulted in reductions in BP and fasting glucose concentration and in improvements in insulin sensitivity. Optimization of children's vitamin D status may improve their cardiovascular health. This trial was registered at clinicaltrials.gov as NCT01797302.

Vitamin D status in Israeli pediatric type 1 diabetes patients: the AWeSoMe Study Group experience and literature review

Background The prevalence of both vitamin D (VitD) deficiency and type 1 diabetes mellitus (T1DM) has increased worldwide over the last few decades. The objectives of this study were: (1) to evaluate the prevalence of VitD deficiency and insufficiency among Israeli youth with T1DM and (2) to assess the association between VitD status, seasonality and T1D glycemic control characteristics. Methods This was a multi-centered, cross-sectional study. VitD levels were routinely tested during the years 2008-2011 in T1DM patients aged up to 21 years. Medical records were reviewed for demographic, clinical and laboratory characteristics. Results The study population consisted of 199 participants (53% males), mean age 12.24±4.11 years, mean T1DM duration 3.77±3.43 years. VitD levels were within the normal range in 19.6%, insufficient (15-29 ng/mL, 37-72 nmol/L) in 62.3% and deficient (<15 ng/mL, <37 nmol/L) in 18.1%. Mean VitD level was higher during the summer than during spring, autumn and winter (28.65 ng/mL, 23.16 ng/mL, 21.65 ng/mL, 17.55 ng/mL, respectively, p<0.001). Mean VitD level was higher among secular patients compared to the religious (whole-year heavily dressed) population (23.57 ng/mL, 15.54 ng/mL, respectively, p<0.001). VitD level was negatively associated with body mass index calculation of standard deviation scores (BMI-SDS), high-density lipoprotein (HDL) and age at diagnosis (r=-0.171, p=0.016; r=-0.149, p=0.043; r=-0.150, p=0.037, respectively). No association was demonstrated with disease duration and glycemic control indices and metabolic parameters. Conclusions VitD insufficiency is largely prevalent among Israeli youth with T1DM, as is in Israeli youth in general. The VitD level is associated with seasonality, clothing habits and BMI.

Fat soluble vitamins deficiency in pediatric chronic liver disease: The impact of liver transplantation

BACKGROUND

Children affected with chronic liver disease are at risk for fat-soluble vitamins (FSV) deficiency, in this scenario the role of liver transplant has been only partially explored.

AIMS

This study aimed to evaluate the prevalence of FSV deficiency in a cohort of paediatric patients awaiting liver transplant, analyze relationships between plasma vitamin concentrations and risk of acute rejections and liver fibrosis and assess the impact of the transplant on vitamin status.

METHODS

166 children candidates for liver transplant were retrospectively evaluated. Vitamin concentrations were measured before and 12 months after transplantation.

RESULTS

Before transplant vitamin A, vitamin E and vitamin D deficiency was found in 66.6%, 40.6% and 36.3% of patients, respectively. 12 months after surgery, the prevalence of deficiency decreased to 29,5% and 2,6% for vitamin A and E while remained the same for vitamin D (36.3%). No association was found between vitamin status and the risk of acute rejections or the severity of liver fibrosis.

CONCLUSION

Liver transplant was effective to improve vitamin A and E, but it did not affect vitamin D. A consensus is needed to define optimal nutritional management of these patients in order to prevent deficiencies.

Vitamin D, and Maternal and Child Health

Vitamin D has important roles in calcium metabolism and in the prevention of rickets and osteomalacia; low levels of 25-hydroxyvitamin D are common in the general population and amongst pregnant women. Whilst there is a wealth of observational evidence linking vitamin D deficiency to a wide range of disease outcomes, there are currently few high-quality randomised controlled trials to confirm any causal associations, although many are currently in progress. Furthermore, currently, the vast majority of published guidelines recommend standard supplemental vitamin D doses for children and pregnant women, yet there is increasing recognition that individual characteristics and genetic factors may influence the response to supplementation. As such, future research needs to concentrate on documenting definite beneficial clinical outcomes of vitamin D supplementation, and establishing personalised dosing schedules and demonstrating effective approaches to optimising initiation and adherence.

WITHDRAWN: Fat soluble vitamins deficiency in pediatric chronic liver disease: The impact of liver transplantation

The Publisher regrets that this article is an accidental duplication of an article that has already been published, https://doi.org/10.1016/j.dld.2019.10.005. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

The Demographics of Fractures and Dislocations Across the Entire United States due to Common Sports and Recreational Activities

BACKGROUND

There exists little nationwide data regarding fracture and dislocation patterns across a wide variety of sporting activities for all ages and sexes.

HYPOTHESIS

Participant demographics (age and sex) will vary with regard to fracture and joint dislocation sustained during sport-related activities.

STUDY DESIGN

Descriptive epidemiology study.

LEVEL OF EVIDENCE

Level 3.

METHODS

The National Electronic Injury Surveillance System All Injury Program data 2005 through 2013 were accessed; 18 common sports and recreational activities in the United States were selected. Statistical software was used to calculate the numbers of fractures and dislocations, and incidence was calculated using US Census Bureau data. Multivariate logistic regression analysis determined the odds ratios (ORs) for the occurrence of a fracture or dislocation.

RESULTS

A fracture occurred in 20.6% and a joint dislocation in 3.6% of the emergency department visits for sports-related injuries; annual emergency department visit incidence was 1.51 for fractures and 0.27 for dislocations (per 1000 people). Most of the fractures occurred in football (22.5%). The OR for fracture was highest for inline skating (OR, 6.03), males (OR, 1.21), Asians, whites, and Amerindians compared with blacks (OR, 1.46, 1.25, and 1.18, respectively), and those older than 84 years (OR, 4.77). Most of the dislocations occurred in basketball (25.7%). The OR for dislocation was highest in gymnastics (OR, 4.08), males (OR, 1.50), Asians (OR, 1.75), and in those aged 20 to 24 years (OR, 9.04). The most common fracture involved the finger, and the most common dislocation involved the shoulder.

CONCLUSION

Inline skating had the greatest risk for fracture, and gymnastics had the greatest risk for joint dislocation.

CLINICAL RELEVANCE

This comprehensive study of the risks of sustaining a fracture or dislocation from common sports activities across all age groups can aid sports health providers in a better understanding of those sports at high risk and be proactive in prevention mechanisms (protective gear, body training).

Is vitamin D deficiency in obese youth a risk factor for less weight loss during a weight loss program?

BACKGROUND

Vitamin D deficiency is common in obese adolescents and a risk factor for insulin resistance. We investigated if prevailing serum 25-OH vitamin D might predict the body fat loss in a group of obese adolescents undergoing a residential weight loss program.

METHODS

In 92 (35 male) obese adolescents (aged 10.6-19 years) undergoing a residential weight loss program in Belgium, fasting serum 25-OH vitamin D (25-OH-D), insulin, glucose and lipid levels were measured and body composition was assessed by dual-energy X-ray absorptiometry (DXA).

RESULTS

Baseline median (range) serum 25-OH-D level was 17.7 µg/L (3.8-41.8). In total, 55 adolescents had a serum 25-OH-D below 20 µg/L. In 31 adolescents with a low baseline 25-OH-D level, median increase in serum 25-OH-D was 2.4 µg/L (-4.2 to 7.2) after 10 months. This resulted in normal 25-OH-D levels in seven adolescents, whereas median BMI decreased with 1.0 SDS and body fat percentage diminished with 9.9%. Obese adolescents with or without a 25-OH-D level below or above 20 µg/L at baseline had similar changes in body weight, BMI SDS, body fat percentage and body fat mass at the end of the program. The change in serum 25-OH-D did not correlate with change in serum insulin, BMI SDS or body fat percentage and body fat mass.

CONCLUSION

Vitamin D deficiency was present in 55 out of 92 obese adolescents at the start of the summer. Serum 25-OH-D concentration did not predict changes in body fat loss after a residential weight loss program.

Gene Expression and Cardiometabolic Phenotypes of Vitamin D-Deficient Overweight and Obese Black Children

Associations between whole blood transcriptome and clinical phenotypes in vitamin D-deficient overweight and obese children can provide insight into the biological effects of vitamin D and obesity. We determined differentially expressed genes (DEGs) in relation to body mass index (BMI) in vitamin D-deficient black children with a BMI ≥ 85th percentile and ascertained the cardiometabolic phenotypes associated with the DEGs. We examined whole-blood transcriptome gene expression by RNA sequencing and cardiometabolic profiling in 41, 10- to 18-year-old children. We found 296 DEGs in association with BMI after adjusting for age, race, sex, and pubertal status. Cardiometabolic phenotypes associated with the BMI-related DEGs, after adjusting for age, sex, pubertal status, and %total body fat, were (i) flow-mediated dilation (marker of endothelial function), (ii) c-reactive protein (marker of inflammation), and (iii) leptin (adipocytokine). Canonical pathways of relevance for childhood obesity and its phenotypes that were significantly associated with the BMI-related DEGs affected immune cell function/inflammation, vascular health, metabolic function, and cell survival/death; several immune and inflammatory pathways overlapped across the three phenotypes. We have identified transcriptome-based biomarkers associated with BMI in vitamin D-deficient, overweight and obese black children. Modulating effects of vitamin D supplementation on these biomarkers and their related phenotypes need further exploration.

Parameters of Bone and Cardiovascular Health Related to 25-Hydroxyvitamin D Status in Emirati Nationals attending Primary Care and Diabetes services: a retrospective cohort study

Vitamin D deficiency is endemic in people living in the Gulf states. We performed a retrospective analysis of data gathered at the first attendance of 82,396 Emirati nationals to outpatient diabetes, endocrinology and general primary care services at two centres in the United Arab Emirates during 2012–2016. Our aim was to explore associations between vitamin D status and markers of cardiovascular and bone health. In the study population, 67.1% of men and 73.5% of women had serum 25(OH)D of less than 50 nmol/L, with the lowest levels being found in young adults. Among Emirati adults with type 2 diabetes, serum 25(OH)D < 50 nmol/L was associated with an increased risk of a coexisting adverse total cholesterol:HDL (TC:HDL) ratio (odds ratio 2.13 (1.60–2.84), p < 0.001). Correcting for age, sex, body mass index, HbA1c and statin therapy, an increase in 25(OH)D of 1 nmol/L was associated with a 0.01 unit reduction in TC:HDL in this population. In a subset of 1064 adult individuals, 25(OH)D < 25 nmol/L was associated with a reduction in DEXA-measured z-score of −0.29 (−0.44 to −0.15, p < 0.001) at the femoral neck and of −0.25(−0.45 to −0.05, p = 0.015) at L1–4, corrected for body mass index, compared with individuals with 25(OH)D ≥ 75 nmol/L. Our findings raise concerns regarding lifetime burden of cardiovascular disease and bone health for young Emiratis with vitamin D deficiency.

Response to vitamin D replacement in overweight and normal weight children with vitamin D deficiency

PURPOSE

It is well known that obesity is related to vitamin D deficiency (VDD). We investigated the response to vitamin D replacement in normal-weight and overweight children.

METHODS

This was a prospective study including 62 Korean children with VDD. VDD was defined as a serum 25-hydroxycholecalciferol (25(OH)D) concentration &lt;20 ng/mL. Overweight was defined as a body mass index (BMI)≥the 85th percentile (n=21), and normal weight as a BMI between the 5th and 84th percentiles (n=41). All participants received vitamin D3 supplementation (2,000 IU/day) for 8 weeks. The serum levels of 25(OH)D, PTH and biochemical parameters were measured before and after treatment.

RESULTS

The mean age was 10.0±1.4 years in normal-weight children and 10.0±2.1 years in overweight children (P=0.93). After 8 weeks of treatment, 61.9% of normal-weight children and 47.6% of overweight children achieved vitamin D sufficiency (P =0.30). The mean serum 25(OH)D levels after vitamin D replacement were 33.8±7.6 ng/mL and 30.3±6.6 ng/mL in normal-weight and overweight children, respectively (P =0.10). The mean calcium/creatinine ratios after treatment were 0.09±0.07 and 0.08±0.06 in the normal-weight and overweight groups, respectively, and no hypercalciuria was found. In multiple regression analysis, the response to vitamin D replacement was influenced by the BMI (β=-1.0, P=0.03) and sex (β=-4.0, P=0.04).

CONCLUSION

Eight weeks of vitamin D replacement (2,000 IU/day) is sufficient to overcome vitamin D deficiency in normal-weight and overweight children without any complications.

Associations of different body fat deposits with serum 25-hydroxyvitamin D concentrations

BACKGROUND & AIMS

Obesity is a well-established risk factor of vitamin D deficiency. However, it is unclear which fat deposit is most strongly related to serum 25-hydroxyvitamin D (25(OH)D) concentrations. Our aim was to distinguish the specific contributions of total body fat (TBF), abdominal subcutaneous adipose tissue (aSAT), visceral adipose tissue (VAT) and hepatic fat on 25(OH)D concentrations.

METHODS

We performed a cross-sectional analysis of the Netherlands Epidemiology of Obesity study, a population-based cohort study. We used linear regression analyses to examine associations of TBF, aSAT, VAT (n = 2441) and hepatic fat (n = 1980) with 25(OH)D concentrations. Standardized values were used to compare the different fat deposits.

RESULTS

Mean (SD) age and 25(OH)D concentrations of the study population was 56 (6) years and 70.8 (24.2) nmol/L, respectively. TBF was inversely associated with 25(OH)D concentrations in women, but not in men. One percent higher TBF was associated with 0.40 nmol/L (95%CI: -0.67 to -0.13) lower 25(OH)D. aSAT was not associated with 25(OH)D concentrations. One cm² higher VAT was associated with 0.05 nmol/L (-0.09 to -0.02) lower 25(OH)D in men, and 0.06 nmol/L (-0.10 to -0.01) lower 25(OH)D in women. Hepatic fat was only associated with 25(OH)D in men. A tenfold increase in hepatic fat was associated with 6.21 nmol/L (-10.70 to -1.73) lower 25(OH)D. Regressions with standardized values showed VAT was most strongly related to 25(OH)D.

CONCLUSIONS

In women, TBF and VAT were inversely related to 25(OH)D concentrations. In men, VAT and hepatic fat were inversely related to 25(OH)D concentrations. In both groups, VAT was most strongly associated with 25(OH)D concentrations.

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.

Vitamin D Deficiency, Skin Phototype, Sun Index, and Metabolic Risk Among Patients with High Rates of Sun Exposure Living in the Tropics

Objective: We sought to evaluate serum 25-hydroxycholecalciferol (vitamin D [25-OHD]) levels, skin phototype, and sun index in a sample of patients to determine the association between these factors and metabolic risk. Design: This was a cross-sectional study involving 729 adults (50.2% male). Mean age was 65.13±9.18 years, sun index 5.71±5.06, body mass index (BMI) 27.60±5.34 kg/m2, and waist circumference 97.29±12.08cm. Hypertension, metabolic syndrome, and Type 2 diabetes were reported in 77.8, 74.5, and 38.9 percent, respectively; Fitzpatrick Skin Types III and IV were reported in 60.6 percent. Results: Mean serum 25-OHD was 25.72±10.91ng/mL; 31 percent of subjects had serum 25-OHD below 20ng/mL, and 63.1 percent had serum 25-OHD below 30ng/mL. Although there were no significant differences between the vitamin D deficient and sufficient groups regarding age, BMI, waist circumference, or presence of diabetes, in the group with 25-OHD less than 20ng/mL (sun index of 4.5±4.08), higher serum triglycerides and lower high-density lipoprotein cholesterol (HDL-C) levels were measured: triglycerides 179.14±103.53 versus 161.63±90.23mg/dL (p=0.029) and HDL-C 43.48±12.38 versus 45.94±14.14mg/dL (p=0.018) compared to the group with 25-OHD levels of 20ng/mL or higher (sun index: 6.25±5.36). Considering less than 25th percentile (25-OHD: 18.7ng/mL) and 75th percentile or higher (25-OHD: 30.8 ng/mL), the differences in serum triglycerides remained significant: 176.63±103.79 versus 157.47±80.49 (p=0.039). Conclusion: We found a high prevalence of vitamin D deficiency in individuals with high sun exposure, regardless of age, BMI, and waist circumference. This deficiency was associated with increased serum triglycerides and decreased HDL-C levels.

Fat Mass Is Associated with Serum 25-Hydroxyvitamin D Concentration Regardless of Body Size in Men

There are no large community-based studies examining the association of body size vs. body fat with vitamin D status. Association of serum 25-hydroxyvitamin D (25OHD) with body weight and subcategories of body weight defined by fat mass were evaluated in a large, free living population. Out of a total of 29,235 subjects from the 2008–2010 Korean National Health and Nutrition Examination Survey, the relevant data included 6458 subjects over 50 years of age who were analyzed cross-sectionally. Serum 25OHD concentrations were compared in men (n = 3164) and in women (n = 3294) by tertiles of body weight and body fat mass, as measured by Dual-energy X-ray Absorptiometry (DXA) within sex-specific tertiles of body weight. Serum 25OHD was weakly inversely correlated with body weight in the men and the women after adjustment for age (r = −0.075 and −0.073, respectively, p < 0.001 for both). Within each tertile of body weight, serum 25OHD decreased progressively as fat mass increased in men. This pattern was similar in the women but not consistently significant. Whereas body weight predicted a small decrease in serum 25OHD in the men and the women, greater adiposity, for any given weight, predicted larger decreases in the men, but not consistently in women.

Sunlight exposure is just one of the factors which influence vitamin D status

Studies on the determinants of vitamin D status have tended to concentrate on input - exposure to ultraviolet B radiation and the limited sources in food. Yet, vitamin D status, determined by circulating concentrations of 25-hydroxyvitamin D (25(OH)D), can vary quite markedly in groups of people with apparently similar inputs of vitamin D. There are small effects of polymorphisms in the genes for key proteins involved in vitamin D production and metabolism, including 7-dehydrocholesterol reductase, which converts 7-dehydrocholesterol, the precursor of vitamin D, to cholesterol, CYP2R1, the main 25-hydroxylase of vitamin D, GC, coding for the vitamin D binding protein which transports 25(OH)D and other metabolites in blood and CYP24A1, which 24-hydroxylates both 25(OH)D and the hormone, 1,25-dihydroxyvitamin D. 25(OH)D has a highly variable half-life in blood. There is evidence that the half-life of 25(OH)D is affected by calcium intake and some therapeutic agents. Fat tissue seems to serve as a sink for the parent vitamin D, which is released mainly when there are reductions in adiposity. Some evidence is presented to support the proposal that skeletal muscle provides a substantial site of sequestration of 25(OH)D, protecting this metabolite from degradation by the liver, which may help to explain why exercise, not just outdoors, is usually associated with better vitamin D status.

Roles of Vitamins D and K, Nutrition, and Lifestyle in Low-Energy Bone Fractures in Children and Young Adults

The research on skeletal system health in children and young adults, while recognizing the important role of calcium and vitamin D, goes beyond these nutritional standards. This review focuses on the role of vitamin K in combination with vitamin D and other factors in bone health. The current understanding is that maintaining bone health and prevention of low-energy fractures in any pediatric population includes nutritional factors combined with an active lifestyle. Calcium, vitamin D, and vitamin K supplementation contribute independently and collectively to bone health. The beneficial role of vitamin K, particularly vitamin K2 as menaquinone-7 (MK-7), in bone and cardiovascular health is reasonably well supported scientifically, with several preclinical, epidemiological, and clinical studies published over the last decade. Osteocalcin and matrix-Gla (glutamate-containing) protein (MGP) exemplify vitamin K-dependent proteins involved in building bone matrix and keeping calcium from accumulating in the arterial walls, respectively. An important part of the mechanism of vitamin K involves carboxylation and posttranslational activation of the family of vitamin K-dependent proteins, which prevent expression of pro-inflammatory factors and support improvement in bone mineral concentration, bone mineral density, and the quality of bone matrix. Understanding the combined approach to a healthy skeletal system in children and young adults, including the roles of vitamins D and K, calcium, healthy diet, and exercise, is particularly important in view of reports of subclinical insufficiency of vitamins D and K in otherwise healthy pediatric populations with low-energy bone fractures.

Vitamin D supplementation and body fat mass: a systematic review and meta-analysis

Studies have indicated that 25-hydroxyvitamin D (25(OH)D) level in obese is lower than normal weight subjects; however, results of studies that investigated relationship between 25(OH)D and fat mass are inconsistent. In addition, several randomized clinical trials (RCTs) have studied the influence of cholecalciferol supplement on percentage fat mass (PFM) but their results are conflicting. The objectives were to investigate the association between vitamin D3 and PFM pooling together observational studies and RCTs. PubMed/MEDLINE, Cochrane, and Scopus were comprehensively searched from inception to September 2016. The Fisher's Z (SE) of correlation coefficient and mean (SD) of changes in PFM from baseline were used to perform meta-analysis in observational studies and RCTs, respectively. To determine potential source of heterogeneity, subgroup and meta-regression analyses were conducted. Pooling correlation coefficients showed an inverse association between PFM (Fisher's Z: - 0.24, 95% CI: - 0.30 to -0 .18) and FM (Fisher's Z: - 0.32, 95% CI: - 0.43 to - 0.22) and 25(OH)D. Subgroup analysis revealed continent but not gender influence on the effect size. Meta-regression analysis indicated that age, latitude, and longitude are not sources of heterogeneity. Combining trials showed vitamin D3 supplementation had a mild but insignificant effect on PFM (- 0.31%, 95% CI: - 1.07 to 0.44). Subgroup analyses indicated that type of cholecalciferol and treatment regimens explain source of heterogeneity. Age, baseline body mass index, dose of cholecalciferol, length of study, female (%), and baseline 25(OH)D are not source of heterogeneity. In conclusion, our results state that 25(OH)D level is inversely correlated with PFM but cholecalciferol supplementation had no effect on PFM.

Vitamin D, PCOS and androgens in men: a systematic review

BACKGROUND

Accumulating evidence from animal and human studies suggests that vitamin D is involved in many functions of the reproductive system in both genders.

AIM

The aim of this review was to provide an overview on the effects of vitamin D on polycystic ovary syndrome (PCOS) in women and androgen metabolism in men.

METHODS

We performed a systematic literature search in PubMed for relevant English language publications published from January 2012 until September 2017.

RESULTS AND DISCUSSION

The vitamin D receptor and vitamin D-metabolizing enzymes are found in reproductive tissues of women and men. In women, vitamin D status has been associated with several features of PCOS. In detail, cross-sectional data suggest a regulatory role of vitamin D in PCOS-related aspects such as ovulatory dysfunction, insulin resistance as well as hyperandrogenism. Moreover, results from randomized controlled trials (RCTs) suggest that vitamin D supplementation may be beneficial for metabolic, endocrine and fertility aspects in PCOS. In men, vitamin D status has been associated with androgen levels and hypogonadism. Further, there is some evidence for a favorable effect of vitamin D supplementation on testosterone concentrations, although others failed to show a significant effect on testosterone levels.

CONCLUSION

In summary, vitamin D deficiency is associated with adverse fertility outcomes including PCOS and hypogonadism, but the evidence is insufficient to establish causality. High-quality RCTs are needed to further evaluate the effects of vitamin D supplementation in PCOS women as well as on androgen levels in men.

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

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

Vitamin D in obesity

PURPOSE OF REVIEW

Vitamin D is essential for bone health, and may also have important functions in immunity and other systems. Vitamin D deficiency is common, and testing and supplementation is increasing. Serum vitamin D is lower in obese people; it is important to understand the mechanism of this effect and whether it indicates clinically significant deficiency.

RECENT FINDINGS

Vitamin D is fat soluble, and distributed into fat, muscle, liver, and serum. All of these compartments are increased in volume in obesity, so the lower vitamin D likely reflects a volumetric dilution effect and whole body stores of vitamin D may be adequate. Despite lower serum vitamin D, obese adults do not have higher bone turnover or lower bone mineral density. Patients undergoing bariatric surgery do have bone loss, and ensuring vitamin D sufficiency in these patients may help to attenuate bone loss.

SUMMARY

Lower vitamin D in obese people is a consistent finding across age, ethnicity, and geography. This may not always reflect a clinical problem. Obese people need higher loading doses of vitamin D to achieve the same serum 25-hydroxyvitamin D as normal weight.

Utility of sun-reactive skin typing and melanin index for discerning vitamin D deficiency

BackgroundSkin color, a vitamin D status determinant, can be assessed subjectively by Fitzpatrick sun-reactive skin typing (FST) and objectively by melanin index (MI). FST was validated against MI for discerning vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D) <20 ng/ml) in children.MethodsWe measured FST, MI, and serum 25(OH)D in healthy, 8- to 18-year-old children from one of two vitamin D trials. MI from forehead, hand, and upper arm split at the median of the more racially balanced study cohort and FST (I-III vs. IV-V) were used for discriminating vitamin D deficiency.ResultsA total of 296 participants (mean age, 12.3±2.3 years; black, 208; FST IV-V, 209; 25(OH)D <20 ng/ml, 159) were studied. MI and FST had a strong positive association. Serum 25(OH)D was negatively associated with MI and FST. Sensitivity, specificity, and predictive values were similar for discriminating vitamin D deficiency between higher vs. lower MI and between FST I-III vs. IV-V. ROC area under the curves for FST (0.59) and MI (forehead (0.63); hand (0.62); and arm (0.64)) were similar.ConclusionsFST is comparable to MI for discerning vitamin D deficiency and can be deemed as an inexpensive, useful surrogate measure of skin color in the context of vitamin D research.

Vitamin D Deficiency: A Potential Modifiable Risk Factor for Cardiovascular Disease in Children with Severe Obesity

Severe obesity is associated with abnormal lipids and increased risk for cardiovascular disease. Obesity is a risk factor for vitamin D deficiency. We examined relationship between 25-hydroxy vitamin D (25(OH)D) concentrations and lipids in children with severe obesity. Medical records of 376 children were reviewed. Linear regression models and logistic regression were used to examine the relationship between 25(OH)D and lipids after adjustment for age, gender, season of blood draw, body mass index (BMI) z-score, and BMI % of 95th percentile. Two-hundred sixty-three out of 376 children (70%) had 25(OH)D concentrations < 30 ng/mL. Concentrations of 25(OH)D were positively correlated with those of high-density lipoprotein cholesterol (HDL-C) (r² = 0.08, r = 0.22, β = 0.16, 95% CI = 0.05–0.27, p = 0.004). HDL-C was lower in children with 25(OH)D < 30 ng/mL (n = 263) compared to those with 25(OH)D ≥ 30 ng/mL (n = 113) (41.3 ± 10.2 vs. 46.4 ± 12 mg/dL, p < 0.0001). Children with 25(OH)D concentrations < 30 ng/mL had greater adjusted odds of low HDL-C (<40 mg/dL) compared with those with 25(OH)D ≥ 30 ng/mL (47.9% vs. 29.2%, OR 2.15 (1.33–3.51), p = 0.0019). Total cholesterol and non-HDL-C were not correlated with 25(OH)D concentrations. Vitamin D deficiency is highly prevalent in children with severe obesity. Prospective clinical trials are warranted to determine if vitamin D supplementation can improve HDL-C and potentially decrease risk for cardiovascular disease in children with obesity.

[Prevalence of hypovitaminosis D and associated factors in Spanish population of school children and adolescents]

Objetivo

Analizar la prevalencia de hipovitaminosis D y factores asociados en escolares y adolescentes residentes en una región del norte peninsular.

Diseño

Estudio descriptivo transversal (muestreo de conveniencia).

Emplazamiento

Atención primaria.

Participantes

Fueron incluidos 602 sujetos sanos de raza caucásica con edades comprendidas entre 3,1 y 15,4 años.

Mediciones principales

Se ha calculado la prevalencia de hipovitaminosis D (variable dependiente) según los criterios de la US Endocrine Society: deficiencia (calcidiol < 20 ng/ml), insuficiencia (calcidiol: 20-29 ng/ml) y suficiencia (calcidiol ≥ 30 ng/ml). Se han registrado como variables independientes: sexo, edad, índice de masa corporal, lugar de residencia y estación del año, analizándose su asociación con la hipovitaminosis D mediante regresión logística múltiple.

Resultados

La prevalencia de hipovitaminosis D era del 60,4% (insuficiencia: 44,6%; deficiencia: 15,8%). Las variables asociadas con la hipovitaminosis D eran el sexo femenino (OR: 1,6; IC 95%: 1,1-2,3), la edad puberal (OR: 1,8; IC 95%: 1,2-2,6), las estaciones de otoño (OR: 9,5; IC 95%: 4,8-18,7), invierno (OR: 8,8; IC 95%: 4,5-17,5) y primavera (OR: 13,2; IC 95%: 6,4-27,5), el entorno urbano (OR:1,6; IC 95%: 1,1-2,2) y la obesidad severa (OR: 4,4; IC 95%: 1,9-10,3).

Conclusiones

En la población infantojuvenil existe una alta prevalencia de hipovitaminosis D, y los factores asociados son el sexo femenino, la edad puberal, el otoño, el invierno y la primavera, la obesidad severa y el entorno urbano. Habría que considerar la necesidad de administrar suplementos vitamínicos o ingerir mayores cantidades de sus fuentes dietéticas naturales y/o alimentos enriquecidos durante los meses de otoño, invierno y primavera.

Vitamin D metabolism in human adipose tissue: could it explain low vitamin D status in obesity?

Obesity and a low vitamin D (VD) status, as well as a positive association between them, are prevalent worldwide. Additionally, a low VD status has been positively correlated with metabolic dysfunction (although not so convincingly as for obesity). The VD receptor (VDR) mediates VD biological actions in adipose tissue (AT), where VD can be activated or inactivated/degraded through specific hydroxylation steps. Additionally, AT can also store and release VD when needed. A lower VD activation/VD inactivation ratio and an impaired VDR signaling in AT could contribute to metabolic dysfunction besides the aforementioned association between obesity and VD status. However, subcutaneous (SAT) and visceral AT (VAT) are not expected to be similarly accountable as these two fat depots play differential roles in metabolic regulation/dysfunction. To our knowledge, only three articles disclose the evaluation of the expression of VDR and/or VD hydroxylating enzymes in human SAT and VAT. A clear dependence on the subcutaneous and/or the visceral fat depot is missing for the relationships of a) obesity and/or metabolic dysfunction with VD status and b) adipose VDR signaling and adipose VD activation/VD inactivation ratio with VD status, obesity and/or metabolic dysfunction. Further studies are warranted to unravel the influence of adipose VD metabolism on VD status.