The effect of vitamin D supplementation on serum 25(OH)D in thin and obese women

Bone health in adults with obesity before and after interventions to promote weight loss

Obesity and its associated comorbidities constitute a serious and growing public health burden. Fractures affect a substantial proportion of people with obesity and result from reduced bone strength relative to increased mechanical loading, together with an increased risk of falls. Factors contributing to fractures in people with obesity include adverse effects of adipose tissue on bone and muscle and, in many people, the coexistence of type 2 diabetes. Strategies to reduce weight include calorie-restricted diets, exercise, bariatric surgery, and pharmacological interventions with GLP-1 receptor agonists. However, although weight loss in people with obesity has many health benefits, it can also have adverse skeletal effects, with increased bone loss and fracture risk. Priorities for future research include the development of effective approaches to reduce fracture risk in people with obesity and the investigation of the effects of GLP-1 receptor agonists on bone loss resulting from weight reduction.

Weight reduction among females undergoing laparoscopic ventral hernia repair: The role of Calcium and Vitamin D3

Objective

To evaluate the role of Vitamin-D and calcium supplementation on preoperative weight reduction in obese women before laparoscopic ventral hernia repair.

Methods

This double-blind clinical trial was conducted at the affiliated health centers of King Faisal University, Al-Ahsa, Saudi Arabia from January 2021 to December 2021. It included forty-five obese women aged 24-56 years, with body mass index (BMI) of 34.0-48.0kg/m2. They were randomly allocated into two groups; the Group-A (N=22) included obese women who received supplementation of 5000IU cholecalciferol (Vitamin-D3), and 1000mg calcium daily for 12 months, while the Group-B (N=23) received no treatment. Measurement of change in weight and BMI and comparison of their pre-operative weight reduction, laparoscopic operative time, and length of hospital stay was done.

Results

There were no differences in patients' biographic data between the two groups. During the study, Vitamin-D level in the patients increased and there was a significant positive association with weight loss. In group-A, the mean weight loss was 11.8±3.5 kg. At the end of first year, their BMI decreased from 36.1±1.6kg/m2 at baseline to 29.7±2.6 kg/m2, whereas in-group-B, the mean weight loss was 6.8±3.1 kg and their BMI decreased from 36.9±2.69kg/m2 at baseline to 32.7±0.93kg/m2. The operation time and the length of hospital stay were shorter in group-A (107 vs.128.min) and (3 vs. 5 days) respectively as compared to Group-B.

Conclusion

Vitamin-D and calcium supplementation contributes to a remarkable weight reduction of preoperative obese female patients, which in turn is associated with significantly better outcome of laparoscopic repair of ventral hernia.

Correlation between maternal and umbilical cord 25-hydroxy-vitamin D levels over a range of values. A prospective observational study from the United Arab Emirates

Worldwide vitamin D insufficiency is remarkably prevalent in both children and adults, including pregnant women. The total amount of the vitamin is best measured by 25-hydroxy-vitamin D (25(OH)D), which is a measurement of total serum cholecalciferol 25(OH)D3 and ergocalciferol 25(OH)D2. There is a known correlation between maternal and umbilical cord blood (UCB) 25(OH)D; however, whether specific maternal demographics or comorbidities influence the correlation remains uncertain. This prospective observational study was designed to study if maternal 25(OH)D levels, maternal age and BMI, amount of supplementation, mode of delivery, diabetes, hypertension/preeclampsia, or sunlight exposure had an impact on the correlation. Women were enrolled in the study at admission to the labor ward. If they agreed to participate, venous blood was directly collected and analyzed for 25(OH)D. The UCB was sampled after delivery from the unclamped cord and immediately analyzed for 25(OH)D. ANOVA, Fisher's exact test, Pearson's correlation, and test of the differences between correlations using Fisher's z-transformation with Bonferroni correction were used accordingly. Of the 298 women enrolled, blood from both the mother and umbilical cord was analyzed successfully for 25(OH)D in 235 cases. The crude correlation between maternal and UCB 25(OH)D was very strong over all values of 25(OH)D (r = 0.905, R2 = 0.821, p <0,001) and remained strong independently of maternal demographics or co-morbidities (r ≥ 0.803, R2 ≥ 0.644, p <0.001). For women who delivered by caesarean section in second stage the correlation was strong (r ≥ 0.633, R2 ≥ 0.4, p <0.037). Test of differences between correlations showed significant stronger correlation in women with unknown 25(OH)D3 supplementation compared to women receiving 10.000 IU/week (p = 0.02) and 20.000IU/week (p = 0.01) and that the correlation was significantly stronger for women with a BMI of 25-29.9 compared to women with a BMI of <24.9 (p = 0.004) and 30-34.9 (p = 0.002). 213 (91%) women had lower 25(OH)D compared to the neonate, with a mean difference of -13.7nmol/L (SD = 15.6). In summary, the correlation between maternal and UCB 25(OH)D is very strong throughout low to high maternal levels of 25(OH)D with lower levels in maternal blood. Typical maternal demographics and comorbidities did not affect the transition.

Unraveling the complex interplay between obesity and vitamin D metabolism

Vitamin D deficiency and obesity are a worldwide health issue. Obesity refers to the accumulation of excessive fats in the body which could lead to the development of diseases. Obese people have low vitamin D levels for several reasons including larger volume of distribution, vitamin D tightly bound in fatty tissues, reduced absorption, and diets with low vitamin D. Accurately measuring vitamin D metabolites is challenging. The Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-MS/MS) method was developed and validated for the analysis of vitamin D metabolites in the serum. Blood samples were collected from 452 subjects which consisted of baseline (vitamin D deficient obese subjects), follow-up (supplemented obese subjects), and healthy volunteers. The vitamin D metabolites were separated adequately by the developed UHPLC-MS/MS method. Moreover, the validation criteria for the method were within an acceptable range. The baseline, follow-up and even healthy volunteers were deficient in 25OHD3 and 25OHD2. The baseline and healthy subjects had comparable concentration of vitamin D2 and D3. However, healthy subjects had a higher concentration of 25OHD and its epimer compared to the baseline subjects. The vitamin D3 was increased significantly in the follow- up subjects; therefore, the 25OHD3 was increased significantly compared to the baseline as well; however, the increase was insufficient to achieve the optimal range. The UHPLC-MS/MS method test was applied successfully on estimation of vitamin D metabolites in subjects. This study indicates the significance of taking into account the metabolic and storage effects when evaluating the vitamin D status in obese subjects.

Vitamin D Supplementation: A Review of the Evidence Arguing for a Daily Dose of 2000 International Units (50 µg) of Vitamin D for Adults in the General Population

Vitamin D deficiency is considered a public health problem due to its worldwide high prevalence and adverse clinical consequences regarding musculoskeletal health. In addition, vitamin D may also be crucial for the prevention of certain extraskeletal diseases. Despite decades of intensive scientific research, several knowledge gaps remain regarding the precise definition of vitamin D deficiency and sufficiency, the health benefits of improving vitamin D status, and the required vitamin D intakes. Consequently, various societies and expert groups have released heterogeneous recommendations on the dosages for vitamin D supplementation. In this brief narrative review, we outline and discuss recent advances regarding the scientific evidence arguing for a daily vitamin D supplementation with 2000 international units (IU) (50 µg) of vitamin D3 to prevent and treat vitamin D deficiency. According to data from randomized controlled trials (RCTs), such a dose may improve some health outcomes and is sufficient to raise and maintain serum 25(OH)D concentrations above 50 nmol/L (20 ng/mL) and above 75 nmol/L (30 ng/mL) in >99% and >90% of the general adult population, respectively. According to large vitamin D RCTs, there are no significant safety concerns in supplementing such a dose for several years, even in individuals with an already sufficient vitamin D status at baseline. A daily vitamin D supplementation with 2000 IU (50 µg) may be considered a simple, effective, and safe dosage to prevent and treat vitamin D deficiency in the adult general population.

Evaluation of normal range of serum 25 hydroxyvitamin d in iraqi healthy adults: demographic and socioeconomic effects

OBJECTIVE

Aim: To determine the normal range of serum levels of total 25(OH)VD in Iraqi healthy adult subjects and to relate its level with demographic profile and socioeconomic status..

PATIENTS AND METHODS

Materials and Methods: This cross sectional study was carried out at Iraq and the samples were collected during the period from August 2019 to January 2020. It included 649 adult subjects apparently healthy, from three governorates (Baghdad, Al-Anbar and Al-Basrah), Investigations included serum measurement of total 25(OH)D in all included individuals by using ELISA technique. Age, gender, marital state, blood pressure, smoking, sunshine exposure (%), hours of exposure/day, percentage of body surface area exposed, body mass index (BMI) subgroups, waist circumference (WC) subgroups, diet type, sport type and time, geographic factor (governorate) were measured and / or calculated and the levels of 25(OH)D were studied according to each of these factors.

RESULTS

Results: The mean ± SD level of 25(OH)D in total (n=649) studied Iraqi subjects was (16.29 ± 8.22 ng/ml), with women were significantly deficient than men (15.76 ± 6.89 ng/ml, 17.14 ± 6.85 ng/ml; p < 0.01 respectively). However, there was no significant differences in mean values of serum 25(OH)D levels among studied governorates, subgroups of BMI, WC, marital status, smokers and nonsmoker and subgroups of age. The mean value of serum 25(OH)D was found to be decreased in January, October and November as well as according to diet and sport types. There was significant positive correlation between total 25(OH)D and sun exposed surface area, sun exposure duration and with sun exposure area.

CONCLUSION

Conclusions: The mean (±SD) value of serum total 25(OH)D in Iraqi healthy subjects was 16.29 ng/ml (±8.22) reflecting the actual body status of this vitamin with lower concentration in women than in men. Type and time of sport and diet type were the major vitamin D dependent factors.

Effects of medical and surgical treatment on vitamin D levels in obesity

INTRODUCTION

Persons living with obesity treated with bariatric surgery are at a high risk of developing nutritional deficiencies. The primary aim of this observational cohort study was to compare vitamin D levels in patients two years after bariatric surgery (Roux-en-Y gastric bypass/RYGB and sleeve gastrectomy/SG) with a very low-energy diet (VLED). The same subjects were also compared with a population sample from the same region at baseline. The primary hypothesis was that surgery, especially RYGB, would lead to an increased prevalence of vitamin D deficiency compared to subjects treated with VLED. 971 individuals eligible for surgical, RYGB (n = 388), SG (n = 201), and medical treatment (n = 382), in routine care, were included consecutively between 2015 and 2017. A random population sample from the WHO-MONICA project was used as a reference, (n = 414). S-calcium, S-25(OH)D (vitamin D), and S-PTH (parathyroid hormone) were measured in all persons with obesity at baseline and two years after treatment (n = 713). Self-reported use of vitamin D and calcium supplementation was registered.

RESULTS

Vitamin D deficiency (S-25(OH)D <25mmol/l) was found in 5.2% of the persons with obesity at baseline versus 1.7% of the general population (SMD>0.1). S-25(OH)D increased for all treatment groups but was higher in RYGB and SG (SMD>0.1, standardized mean difference). Thirteen subjects (1.8%) had vitamin D deficiency after obesity treatment.

CONCLUSION

Surgical intervention for obesity followed by vitamin D supplementation was not associated with a higher risk for vitamin D deficiency, irrespective of surgery type, compared to individuals on medical treatment. However, persons living with obesity seeking weight loss treatment are more likely to have deficient vitamin D levels compared to the general population.

Efficacy, safety, and dose-response effects of calcifediol supplementation on 25-hydroxyvitamin D, parathyroid hormone, and 1,25-dihydroxyvitamin D levels in healthy adults: An open-label, interventional pilot study

BACKGROUND

Vitamin D deficiency (VDD) is highly prevalent across the globe. Cholecalciferol (Vitamin D3) fails to attain sufficient serum concentrations of 25-hydroxyvitamin D (25(OH)D) in a significant proportion of supplemented individuals. Calcifediol (25-hydroxyvitamin D3) is less studied in healthy adults and its effects on 25(OH)D, parathyroid hormone (PTH), and 1,25-dihydroxyvitamin D (1,25(OH)2D) at higher doses are not well known.

MATERIALS AND METHODS

The study was an open-label, interventional trial recruiting consecutive participants with VDD who were allocated to receive either 2 capsules (50 μg-group) or 1 capsule (25 μg-group) daily doses of calcifediol. Baseline assessment included clinicodemographic parameters, dietary calcium, calcemic (calcium, inorganic phosphate, albumin, alkaline phosphatase, urine spot calcium/creatinine), and hormonal parameters (25(OH)D, PTH, and 1,25(OH)2D). Participants were followed up at 4 and 8 weeks with repeat assessments of calcemic and hormonal parameters.

RESULTS

There were 64 participants, 35 (50 μg-group) and 29 (25 μg-group), without any significant difference in any of the baseline parameters. 97.1% participants in the 50 μg-group (at 4 and 8 weeks) and 93.1% (at 4 weeks) and 96.5% (at 8 weeks) in the 25 μg-group attained 25(OH)D sufficiency (≥30 ng/ml) with calcifediol. The mean serum 25(OH)D was 84.0 ± 27.7 ng/ml in the 50 μg-group and 58.0 ± 23.6 ng/ml in the 25 μg-group group at 4 weeks, which later rose to 94.3 ± 21.8 ng/ml and 76.0 ± 16.4 ng/ml, respectively, at 8 weeks. PTH levels decreased in both groups at both time points. 1,25(OH)2D rose significantly in both groups at 4 and 8 weeks but was not significantly different between both groups. There was no case of incident hypercalcemia or symptomatic nephrolithiasis.

CONCLUSION

Calcifediol is a safe and efficacious alternative for oral Vitamin D supplementation in young adults. Increment in 25(OH)D levels is rapid and dose-dependent.

Therapeutic Effects of Vitamin D on Vaginal, Sexual, and Urological Functions in Postmenopausal Women

Recent years have witnessed the emergence of growing evidence concerning vitamin D's potential role in women's health, specifically in postmenopausal women. This evidence also includes its connection to various genitourinary disorders and symptoms. Numerous clinical studies have observed improvements in vulvovaginal symptoms linked to the genitourinary syndrome of menopause (GSM) with vitamin D supplementation. These studies have reported positive effects on various aspects, such as vaginal pH, dryness, sexual functioning, reduced libido, and decreased urinary tract infections. Many mechanisms underlying these pharmacological effects have since been proposed. Vitamin D receptors (VDRs) have been identified as a major contributor to its effects. It is now well known that VDRs are expressed in the superficial layers of the urogenital organs. Additionally, vitamin D plays a crucial role in supporting immune function and modulating the body's defense mechanisms. However, the characterization of these effects requires more investigation. Reviewing existing evidence regarding vitamin D's impact on postmenopausal women's vaginal, sexual, and urological health is the purpose of this article. As research in this area continues, there is a potential for vitamin D to support women's urogenital and sexual health during the menopausal transition and postmenopausal periods.

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.

Effect of 12-Week BMI-Based Vitamin D3 Supplementation in Parkinson's Disease with Deep Brain Stimulation on Physical Performance, Inflammation, and Vitamin D Metabolites

Parkinson's disease (PD) is the second most common neurodegenerative disease. To manage motor symptoms not controlled adequately with medication, deep brain stimulation (DBS) is used. PD patients often manifest vitamin D deficiency, which may be connected with a higher risk of falls. We administered a 12-week vitamin D₃ supplementation based on BMI (with higher doses given to patients with higher BMI) to investigate its effects on physical performance and inflammation status in PD patients with DBS. Patients were randomly divided into two groups: treated with vitamin D₃ (VitD, n = 13), and supplemented with vegetable oil as the placebo group (PL, n = 16). Patients underwent functional tests to assess their physical performance three times during this study. The serum 25(OH)D₃ concentration increased to the recommended level of 30 ng/mL in the VitD group, and a significant elevation in vitamin D metabolites in this group was found. We observed significant improvement in the Up and Go and the 6 MWT in the VitD group. In inflammation status, we noticed a trend toward a decrease in the VitD group. To conclude, achieving the optimal serum 25(OH)D₃ concentration is associated with better functional test performance and consequently may have a positive impact on reducing falling risk in PD.

The Role of Vitamin D in Obese Children with Non-Alcoholic Fatty Liver Disease and Associated Metabolic Syndrome

Non-alcoholic fatty liver disease (NAFLD) represents a complex chronic condition, which in the absence of screening-monitoring markers and effective standardized treatment is one of the most important issues in pediatric pathology. In this study, we analyzed the role of vitamin D supplementation in obese children with/without NAFLD and the impact on the components of the associated metabolic syndrome (MS). The study included 22 children with simple obesity (SO) and 50 with NAFLD, aged between 6 and 14 years, who received regimen-based therapy or vitamin D supplementation in case of deficiency. Anthropometric and paraclinical data associated with MS were statistically compared before and after treatment. It was observed that there was a statistical association of NAFLD with MS components, which were present both in SO and in the 6-9 years group. Vitamin D deficiency was associated with the presence of obesity, NAFLD and MS components, and correction of the deficiency induced a tendency to normalize the associated parameters. In the case of a treatment strictly based on the regimen, we found decreases in vitamin D values and additional alteration of some parameters. Supplementation with vitamin D potentiates the effects of the specific regimen, and the effects seem to be dependent on the MS components.

Nutritional Assessment of the Symptomatic Patient on a Plant-Based Diet: Seven Key Questions

Plant-based diets, both vegan and vegetarian, which emphasize grains, vegetables, fruits, legumes, nuts, and seeds are increasingly popular for health as well as financial, ethical, and religious reasons. The medical literature clearly demonstrates that whole food plant-based diets can be both nutritionally sufficient and medically beneficial. However, any person on an intentionally restrictive, but poorly-designed diet may predispose themselves to clinically-relevant nutritional deficiencies. For persons on a poorly-designed plant-based diet, deficiencies are possible in both macronutrients (protein, essential fatty acids) and micronutrients (vitamin B12, iron, calcium, zinc, and vitamin D). Practitioner evaluation of symptomatic patients on a plant-based diet requires special consideration of seven key nutrient concerns for plant-based diets. This article translates these concerns into seven practical questions that all practitioners can introduce into their patient assessments and clinical reasoning. Ideally, persons on plant-based diets should be able to answer these seven questions. Each serves as a heuristic prompt for both clinician and patient attentiveness to a complete diet. As such, these seven questions support increased patient nutrition knowledge and practitioner capacity to counsel, refer, and appropriately focus clinical resources.

Effects of Climate, Sun Exposure, and Dietary Intake on Vitamin D Concentrations in Pregnant Women: A Population-Based Study

BACKGROUND

Vitamin D deficiency (VDD) is a global micronutrient issue that commonly occurs in pregnant women, leading to adverse health outcomes. We examined the role of sunlight-related factors and dietary vitamin D intake on vitamin D concentrations among pregnant women in different climate zones.

METHODS

We conducted a nationwide cross-sectional survey in Taiwan between June 2017 and February 2019. The data of 1502 pregnant women were collected, including sociodemographic information and characteristics related to pregnancy, diet, and sun exposure. Serum 25-hydroxyvitamin D concentrations were measured, and VDD was assessed as a concentration of less than 20 ng/mL. Logistic regression analyses were used to explore the factors associated with VDD. Furthermore, the area under the receiver operating characteristic (AUROC) curve was used to analyze the contribution of sunlight-related factors and dietary vitamin D intake to vitamin D status stratified by climate zones.

RESULTS

The prevalence of VDD was 30.1% and was the highest in the north. Sufficient intake of red meat (odds ratio (OR): 0.50, 95% confidence interval (CI): 0.32-0.75; p = 0.002), vitamin D and/or calcium supplements (OR: 0.51, 95% CI: 0.39-0.66; p < 0.001), sun exposure (OR: 0.75, 95% CI: 0.57-0.98; p = 0.034), and blood draw during sunny months (OR: 0.59, 95% CI: 0.46-0.77; p < 0.001) were associated with a lower likelihood of VDD. Additionally, in northern Taiwan, which is characterized by a subtropical climate, dietary vitamin D intake (AUROC: 0.580, 95% CI: 0.528-0.633) had a greater influence on vitamin D status than did sunlight-related factors (AUROC: 0.536, 95% CI: 0.508-0.589) with a z value = 51.98, p < 0.001. By contrast, sunlight-related factors (AUROC: 0.659, 95% CI: 0.618-0.700) were more important than dietary vitamin D intake (AUROC: 0.617, 95% CI, 0.575-0.660) among women living in tropical areas of Taiwan (z value = 54.02, p < 0.001).

CONCLUSIONS

Dietary vitamin D intake was essential to alleviate VDD in the tropical region, whereas sunlight-related factors played a greater role in subtropical areas. Safe sunlight exposure and adequate dietary vitamin D intake should be promoted appropriately as a strategic healthcare program.

Determinants and Effects of Vitamin D Supplementation in Postmenopausal Women: A Systematic Review

Hormonal fluctuations, excessive clothing covering, sunscreen use, changes in body fat composition, a vitamin D-deficient diet, and a sedentary lifestyle can all predispose postmenopausal women to vitamin D deficiency. An effective supplementation plan requires a thorough understanding of underlying factors to achieve the desired therapeutic concentrations. The objective of this study was to conduct a systematic review of the predictors that affect vitamin D status in postmenopausal women. From inception to October 2022, we searched MEDLINE, Embase, Web of Science, Scopus, and clinical trial registries. Randomized clinical trials of postmenopausal women taking supplements of vitamin D with serum 25-hydroxyvitamin D (25(OH)D) measurement as the trial outcome were included. Two independent reviewers screened selected studies for full-text review. The final assessment covered 19 trials within 13 nations with participants aged 51 to 78. Vitamin D supplementation from dietary and pharmaceutical sources significantly increased serum 25(OH)D to optimal levels. Lower baseline serum 25(OH)D, lighter skin color, longer treatment duration, and prolonged skin exposure were all associated with a better response to vitamin D supplementation in postmenopausal women.

The effect of vitamin D supplementation on body composition in nursing mothers with overweight or obesity: a randomized double-blind placebo-controlled clinical trial

BACKGROUND

This study aimed to evaluate the effect of vitamin D3 supplementation on body composition and anthropometric measures of nursing mothers.

METHODS

In a double-blind, randomized clinical trial, 90 nursing mothers with overweight or obesity were randomized into three groups for 12 weeks: two groups of vitamin D3 supplementation (2000 IU/d (VD1), n = 32 and 4000 IU/d (VD2), n = 29) and placebo (PL) group (n = 29). The information on body composition was obtained using the body impedance analysis (BIA) method. Serum 25-Hydroxy vitamin D (25(OH) D), Intact Parathyroid Hormone (iPTH), calcium, and phosphorus were measured before and after the intervention. Data were analyzed based on the intention-to-treat (ITT) method. Two-way repeated measure ANOVA (mixed ANOVA) was applied to assess whether the mean changes in the results from baseline to 12 weeks differ in the three groups.

RESULTS

There was a significant increase in the serum 25(OH) D concentration in the VD2 group compared to VD1 and PL groups (mean change (MC), 12.3 ng/ml; 95% CI, 9.4/15.0, p-value < 0.001). In addition, fat mass (MC, - 4.3 kg; 95% CI, - 7.0/- 1.1, p-value < 0.007), fat mass index (MC, - 1.6; 95% CI, - 2.6/- 0.5, p-value < 0.006) and body fat percentage (MC, - 8.1; 95% CI, - 12.0/- 4.2, p-value < 0.007) reduced in VD2 group as compared with VD1 and PL groups.

CONCLUSION

The intake of 4000 IU/d vitamins D3 supplementation would elevate circulating 25(OH) D concentrations in nursing mothers with overweight or obesity and improve some indices of body composition.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials ( http://www.irct.ir : IRCT20140413017254N6) registered on 11-04-2018. The graphical abstract of this clinical trial, is a figure that explains the final results of the manuscript in a clear and attractive way.

Efficacy of vitamin D supplementation in reducing body mass index and lipid profile in healthy young adults in Colombia: a pilot randomised controlled clinical trial

The objective of the present study was to evaluate the efficacy of oral administration of vitamin D supplementation in reducing BMI and lipid profile in adolescents and young adults from a cohort in Bucaramanga, Colombia. One hundred and one young adults were randomly assigned to one of two doses of vitamin D [1000 international units (IU) or 200 IU] administered daily for 15 weeks. The primary outcomes were serum 25(OH)D levels, BMI and lipid profile. The secondary outcomes were waist-hip ratio, skinfolds and fasting blood glucose. We found a mean ± sd plasma concentration of 25-hydroxyvitamin D [25(OH)D] was 25⋅0 ± 7⋅0 ng/ml at baseline, and after 15 weeks, it increased to 31⋅0 ± 10⋅0 ng/ml in the participants who received a daily dose of 1000 IU, (P < 0⋅0001). For the participants in the control group (200 IU), it went from 26⋅0 ± 8⋅0 ng/ml to 29⋅0 ± 8⋅0 ng/ml (P = 0⋅002). There were no differences between groups in body mass index. There was a statistically significant decrease in LDL-cholesterol between the intervention group v. the control group (mean difference -11⋅50 mg/dl (95 % CI -21⋅86 to -1⋅15; P = 0⋅030). The conclusions of the present study were two different doses of vitamin D supplementation (200 IU v. 1000 IU) produced changes in serum 25(OH)D levels over 15 weeks of administration in healthy young adults. No significant changes were found in the body mass index when the effect of the treatments was compared. A significant reduction in LDL-cholesterol was found when comparing the two intervention groups. Trial registration: NCT04377386.

Sex differences in the association of physical activity levels and vitamin D with obesity, sarcopenia, and sarcopenic obesity: a cross-sectional study

BACKGROUND

The relationship between vitamin D and sarcopenia was inconsistent between men and women. Physical activity (PA) may interact with vitamin D on sarcopenia. However, the sex-specific relationships of vitamin D, PA and sarcopenia have yet elucidated. We aimed to examine the sex differences in the relation between vitamin D status, PA levels, obesity and sarcopenia in community-dwelling middle-aged and older adults, as well as whether vitamin D status is a modifier in the relationship between PA and sarcopenia.

METHODS

The current study was a cross-sectional study based on the baseline survey of the West China Health and Aging Trend (WCHAT) study. A total of 3713 participants aged ≥ 50y were included in our study. Sarcopenia was defined according to the Asian Working Group for Sarcopenia (AWGS) 2019 consensus. Obesity was defined by body mass index (BMI) (≥ 28 kg/m2) and body fat mass percentage (≥ 60th percentile in each sex group). 25-hydroxyvitamin D was measured by chemiluminescent microparticle immunoassay and PA was evaluated by a validated China Leisure Time Physical Activity Questionnaire (CLTPAQ). Multinomial logistic regression was performed to examine the relationship between PA, vitamin D and sarcopenia and obesity.

RESULTS

Low PA was significantly associated with higher odds of sarcopenia in women only (OR = 1.70,95%CI:1.18,2.46, p < 0.01). Vitamin D deficiency was only associated with sarcopenia in men (OR = 1.85,95%CI: 1.27,2.69, p < 0.01). Low PA was significantly associated with obesity, sarcopenia, and sarcopenic obesity only in participants with serum 25(OH)D < 20 ng/ml.

CONCLUSIONS

The role of vitamin D and PA in obesity and sarcopenia was different between men and women, and the relationship between PA and sarcopenia was modified by serum vitamin D status. These findings highlighted the need to supplement vitamin D in individuals with physical inactivity and provide different interventions strategies to sarcopenia in men and women.

TRIAL REGISTRATION

Clinical trial number: ChiCTR1800018895.

Vitamin D Status for Chinese Children and Adolescents in CNNHS 2016-2017

Vitamin D is very important in maintaining children's bone health because of its regulatory role in calcium and phosphate metabolism. To better understand vitamin D status and related risk factors of children and adolescents in China, this study analyzed the 25-hydroxyvitamin-D (25(OH)D) concentration of children and adolescents aged 6-17 years in China and assessed the risk factors of vitamin D deficiency and insufficiency. We analyzed the data of 25(OH)D concentration collected from the China National Nutrition and Health Survey of Children and Lactating Mothers in 2016-2017 (CNNHS 2016-2017). The age, sex, region type, ethnicities, season, weight and height were recorded, measured by unified questionnaire, equipment and standards. The concentration of 25(OH)D was detected by LC-MS/MS. A total of 64,391 participants from the cross-sectional study of CNNHS in 2016-2017 were included in this study. The median serum 25(OH)D concentration was 17.70 (13.20-22.68) ng/mL, 18.70 (14.10-23.80) ng/mL in boys and 16.60 (12.40-21.40) ng/mL in girls. The total prevalence rate of vitamin D deficiency and insufficiency was 65.98% when the cut-off was 20 ng/mL, 60.42% for boys and 71.99% for girls. According to the results of logistic regression analysis, girls aged above 12 y, living in midlands and northern regions, in spring and winter seasons and with abdominal obesity will have a significantly increased risk of vitamin D deficiency and insufficiency among Chinese children and adolescents. The results showed that vitamin D deficiency and insufficiency are very common among children and adolescents aged 6-17 y in China. They should be encouraged to have more effective sunlight exposure, increased intake of vitamin D from food or supplements in their diet, especially for those aged above 12 y, living in the northern or midlands areas, in spring and winter, and abdominally obese.

Definition, Assessment, and Management of Vitamin D Inadequacy: Suggestions, Recommendations, and Warnings from the Italian Society for Osteoporosis, Mineral Metabolism and Bone Diseases (SIOMMMS)

In the recent years, both the prescriptions of serum 25(OH)D levels assay, and vitamin D supplementation are constantly increasing, as well as the costs to be incurred relating to these specific aspects. As in many other countries, the risk of vitamin D deficiency is particularly high in Italy, as recently confirmed by cohort studies in the general population as well as in patients with metabolic bone disorder. Results confirmed the North-South gradient of vitamin D levels described among European countries, despite the wide use of supplements. Although vitamin D supplementation is also recommended by the Italian Medicine Agency for patients at risk for fragility fracture or for initiating osteoporotic medication, the therapeutic gap for osteoporosis in Italy is very high. There is a consistent proportion of osteoporotic patients not receiving specific therapy for osteoporosis following a fragility fracture, with a poor adherence to the recommendations provided by national guidelines and position paper documents. The failure or inadequate supplementation with vitamin D in patients on antiresorptive or anabolic treatment for osteoporosis is thought to further amplify the problem and exposes patients to a high risk of re-fracture and mortality. Therefore, it is important that attention to its possible clinical consequences must be given. Thus, in light of new evidence from the literature, the SIOMMMS board felt the need to revise and update, by a GRADE/PICO system approach, its previous original recommendations about the definition, prevention, and treatment of vitamin D deficiency in adults, released in 2011. Several key points have been here addressed, such as the definition of the vitamin D status: normality values and optimal values; who are the subjects considered at risk of hypovitaminosis D; opportunity or not of performing the biochemical assessment of serum 25(OH)D levels in general population and in subjects at risk of hypovitaminosis D; the need or not to evaluate baseline serum 25(OH)D in candidate subjects for pharmacological treatment for osteoporosis; how and whether to supplement vitamin D subjects with hypovitaminosis D or candidates for pharmacological treatment with bone active agents, and the general population; how and whether to supplement vitamin D in chronic kidney disease and/or chronic liver diseases or under treatment with drugs interfering with hepatic metabolism; and finally, if vitamin D may have toxic effects in the subject in need of supplementation.

Sixteen-Week Vitamin D3 Supplementation Increases Peripheral T Cells in Overweight Black Individuals: Post hoc Analysis of a Randomized, Double-Blinded, Placebo-Controlled Trial

Background: Vitamin D is considered to modulate T-cell function, which has been implicated in the treatment of inflammatory conditions. However, there is limited knowledge on the effects of vitamin D and its influences on circulating T-cell profiles in humans, particularly in overweight Black individuals who are more likely to be vitamin D insufficient (serum 25(OH)D concentrations of ≤20 ng/mL). Thus, this study tested the hypothesis that vitamin D supplementation modulates T-cell composition, which is in a dose-dependent manner. Methods: A 16-week randomized, double-blinded, placebo-controlled trial of vitamin D3 supplementation was undertaken in 70 overweight/obese Black people (mean age = 26 years, 82% female) with 25 hydroxyvitamin D ≤ 20 ng/mL at baseline. Subjects were randomly assigned a supervised monthly oral vitamin D3 equivalent to approximately 600 IU/day (n = 17), 2000 IU/day (n = 18), 4000 IU/day (n = 18), or a placebo (n = 17). Fresh peripheral whole blood was collected and CD3+, CD4+ and CD8+ cell counts and percentages were determined by flow cytometry at baseline and at 16 weeks, among 56 subjects who were included in the analyses. Results: A statistically significant increase in CD3+% in the 2000 IU/day vitamin D3 supplementation group, and increases in CD4+% in the 2000 IU/day and 4000 IU/day vitamin D3 supplementation groups were observed (p-values < 0.05) from the changes in baseline to 16 weeks. Further adjustments for age, sex and BMI showed that 2000 IU/day vitamin D3 supplementation increased in CD3+ count, CD3%, CD4 count, and CD4%, as compared to the placebo group (p-values < 0.05). Moreover, the highest serum 25(OH)D quantile group had the highest CD3% and CD4%. Conclusions: Sixteen-week vitamin D3 supplementation increases peripheral blood T-cell numbers and percentages in overweight/obese Black patients with vitamin D insufficiency. This resulting shift in circulating T-cell composition, particularly the increase in T helper cells (CD4+ cells), suggests that vitamin D supplementation may improve immune function in Black individuals.

Vitamin D supplementation positively affects anthropometric indices: Evidence obtained from an umbrella meta-analysis

Despite the growing evidence from meta-analyses on vitamin D’s anti-obesity properties, their results are controversial. The current umbrella review was performed to assess the available evidence and provide a conclusive explanation in this regard. The international databases PubMed, Scopus, Embase, Web of Science and Google Scholar were systematically searched till March, 2022. A random-effects model was used to run the meta-analysis. All meta-analyses that examined the effect of vitamin D supplementation on BW, BMI, WC, and fat mass were included. Findings of 14 meta-analyses revealed that vitamin D supplementation reduced body mass index (BMI) (ES: −0.11 kg/m²; 95% CI: −0.18, −0.05, p?0.001; I² = 61.0%, p < 0.001), and waist circumference (WC) (ES = −0.79 cm; 95% CI: −1.20, −0.37; p < 0.001; I² = 46.5%, p = 0.096) in comparison to control group. However, the effects of vitamin D on body weight (ES = −0.16 kg, 95% CI: −0.36, 0.04; p = 0.125; I² = 57.0%, p = 0.017), and fat mass (ES: 0.02, 95% CI: −0.20, 0.24, p = 0.868; I² = 0.0%, p = 0.531) were not considerable. Vitamin D supplementation significantly improved levels of obesity indices such as BMI, and WC.

Protocol for the Vitamin D Oral Replacement in Asthma (VDORA) study

Obesity and asthma are epidemic in the United States and obesity is an independent risk factor for asthma. Low vitamin D levels (i.e. serum 25-hydroxyvitamin D) have been reported in patients with reduced lung function, more frequent respiratory infections, and asthma exacerbations. Experts have proposed that serum levels > 40 ng/mL are required to offer the immunomodulatory benefits of vitamin D. Low vitamin D levels are common in both obesity and asthma, but it is not known whether supplementation with vitamin D improves asthma symptoms. Guidance for drug development stresses the importance of early phase studies to establish accurate population pharmacokinetics (PK) and drug dosing prior to larger phase 3 trials. The PK of this fat-soluble vitamin in children with increased adiposity are unknown; as are the doses need to reach proposed immunomodulatory levels. The objective of this study is to characterize the PK of vitamin D in children with obesity. Children ages 6--18 years who had physician diagnosed asthma and a body mass index (BMI) >85th percentile will be randomized to receive either standard daily dosing or loading doses followed by standard daily dosing. Blood samples will be obtained to characterize the PK of vitamin D. The results of this study will be used to identify a sufficient dose of vitamin D supplement to raise serum levels above a pre-specified value that may result in anti-inflammatory actions that could improve asthma symptoms.

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.

Interrelationship between Vitamin D and Calcium in Obesity and Its Comorbid Conditions

Obesity has been linked to vitamin D (VD) deficiency and low calcium (CAL) status. In the last decade, dietary supplementation of vitamin D and calcium (VD–CAL) have been extensively studied in animal experiments and human studies. However, the physiological mechanisms remain unknown as to whether the VD–CAL axis improves homeostasis and reduces biomarkers in regulating obesity and other metabolic diseases directly or indirectly. This review sought to investigate their connections. This topic was examined in scientific databases such as Web of Science, Scopus, and PubMed from 2011 to 2021, and 87 articles were generated for interpretation. Mechanistically, VD–CAL regulates from the organs to the blood, influencing insulin, lipids, hormone, cell, and inflammatory functions in obesity and its comorbidities, such as non-alcoholic fatty liver disease, cardiovascular disease, and type-2 diabetes mellitus. Nevertheless, previous research has not consistently shown that simultaneous VD–CAL supplementation affects weight loss or reduces fat content. This discrepancy may be influenced by population age and diversity, ethnicity, and geographical location, and also by degree of obesity and applied doses. Therefore, a larger prospective cohort and randomised trials are needed to determine the exact role of VD–CAL and their interrelationship.

A comprehensive look into the association of vitamin D levels and vitamin D receptor gene polymorphism with obesity in children

Childhood obesity accounts for several psychosocial and clinical consequences. Psychosocial consequences include lower self-esteem, social isolation, poor academic achievement, peer problems, and depression, whereas clinical consequences are cardiovascular diseases, type 2 diabetes, dyslipidemia, cancer, autoimmune diseases, girls early polycystic ovarian syndrome (PCOS), asthma, bone deformities, etc. A growing number of studies have uncovered the association of childhood obesity and its consequences with vitamin-D (vit-D) deficiency and vitamin-D receptor (VDR) gene polymorphisms such as single nucleotide polymorphisms (SNPs), e.g., TaqI, BsmI, ApaI, FokI, and Cdx2. Considering the impact of vit-D deficiency and VDR gene polymorphisms, identifying associated factors and risk groups linked to lower serum vit-D levels and prevention of obesity-related syndromes in children is of utmost importance. Previously published review articles mainly focused on the association of vit-D deficiency with obesity or other non-communicable diseases in children. The nature of the correlation between vit-D deficiency and VDR gene polymorphisms with obesity in children is yet to be clarified. Therefore, this review attempts to delineate the association of obesity with these two factors by identifying the molecular mechanism of the relationship.

Low serum 25-hydroxyvitamin D level is associated with obesity and atherogenesis in adolescent boys

PURPOSE

We investigated the relationship of 25-hydroxyvitamin D (25[OH]D) level with obesity and atherosclerosis in Japanese adolescents.

METHODS

We examined 492 children (247 boys and 245 girls) aged 12-13 years. The serum 25(OH)D level was compared among underweight, healthy weight, and overweight children. Spearman correlation coefficient analysis was performed to examine the relationships between the 25(OH)D level and body mass index (BMI), plasma lipids, and blood pressure and to compare the latter between the normal (≥20 ng/mL) and low (<20 ng/mL) 25(OH)D groups. Further, we performed a multiple regression analysis to assess the effect on the 25(OH)D level.

RESULTS

The serum 25(OH)D level was significantly lower in overweight (20.5±2.7 ng/mL) than in healthy-weight boys (22.4±3.3 ng/mL) (P=0.004). Spearman correlation coefficients comparing the relationship of the 25(OH)D level with BMI, high-density lipoprotein cholesterol (HDL-C), and atherogenic index indicated significance in boys (ρ=-0.238 [P<0.0001], ρ=0.197 [P=0.002], and ρ=-0.146 [P=0.022], respectively). In boys, the multiple regression analysis results showed that BMI had negative and HDL-C had positive effects on the 25(OH)D level. The first was higher and the latter was lower in boys with low 25(OH)D level than in those with normal levels, respectively (P<0.05). No significant correlations were detected in girls.

CONCLUSION

Low serum 25(OH)D level was associated with obesity and increased atherogenic risk in adolescent boys only. This sex difference was probably mediated by body composition, sun exposure, estrogen, and adiponectin, which are characteristics of puberty.

Serum 25(OH)D Levels Modify the Association between Triglyceride and IR: A Cross-Sectional Study

BACKGROUND

Triglycerides and 25(OH)D had been reported as correlates of IR, but the results suggest substantial heterogeneity across races. In addition, little research reported on whether different 25(OH)D levels affect triglycerides and IR. Therefore, a similar study on the US population would be a great addition to the current one. This study investigated the association between triglycerides and IR at different 25(OH)D levels.

METHODS

A total of 19,926 participants were included, each containing specific indicators for the study project. IR was estimated as a HOMA-IR index ≥2.73. Four multivariate logistic regression models were developed to analyze the association between TG and IR and whether different 25(OH)D levels influenced this association. Smoothed fitting curves were plotted.

RESULTS

Triglyceride was significantly associated with IR (OR: 1.3, 95 CI %), while this association received different 25(OH)D levels (P for interaction <0.001). The effect value OR was 1.33 with the high levels, and its effect value OR was 1.28 with the low levels.

CONCLUSION

This study demonstrates that triglyceride levels are significantly associated with insulin in the US adult population and can be used as a predictor of IR. This correlation was compromised at different 25 (OH)D levels, so future studies need to be explored in more ethnically diverse contexts.

Vitamin D modulates cortical transcriptome and behavioral phenotypes in an Mecp2 heterozygous Rett syndrome mouse model

Rett syndrome (RTT) is an X-linked neurological disorder caused by mutations in the transcriptional regulator MECP2. Mecp2 loss-of-function leads to the disruption of many cellular pathways, including aberrant activation of the NF-κB pathway. Genetically attenuating the NF-κB pathway in Mecp2-null mice ameliorates hallmark phenotypes of RTT, including reduced dendritic complexity, raising the question of whether NF-κB pathway inhibitors could provide a therapeutic avenue for RTT. Vitamin D is a known inhibitor of NF-κB signaling; further, vitamin D deficiency is prevalent in RTT patients and male Mecp2-null mice. We previously demonstrated that vitamin D rescues the aberrant NF-κB activity and reduced neurite outgrowth of Mecp2-knockdown cortical neurons in vitro, and that dietary vitamin D supplementation rescues decreased dendritic complexity and soma size of neocortical projection neurons in both male hemizygous Mecp2-null and female heterozygous mice in vivo. Here, we have identified over 200 genes whose dysregulated expression in the Mecp2+/- cortex is modulated by dietary vitamin D. Genes normalized with vitamin D supplementation are involved in dendritic complexity, synapses, and neuronal projections, suggesting that the rescue of their expression could underpin the rescue of neuronal morphology. Further, there is a disruption in the homeostasis of the vitamin D synthesis pathway in Mecp2+/- mice, and motor and anxiety-like behavioral phenotypes in Mecp2+/- mice correlate with circulating vitamin D levels. Thus, our data indicate that vitamin D modulates RTT pathology and its supplementation could provide a simple and cost-effective partial therapeutic for RTT.

Serum 25-hydroxyvitamin D is associated with fracture risk only during periods of seasonally high levels in women with a high body mass index

Serum 25-hydroxyvitamin D (S-25OHD) is used to assess vitamin D status and is known to be affected by season and fat mass. Because these factors are often ignored when interpreting S-25OHD, assessment of vitamin D associations with disease outcomes may be distorted. We aimed to investigate the impact of season of blood draw and fat mass on the association of S25OHD with fracture risk. We enrolled 5000 women, mean ± SD age 68 ± 7 years, with dual-energy x-ray absorptiometry (DXA) scans and blood collection in a population-based cohort. Proportional hazards regression, stratified by season and fat mass, was used to determine hazard ratios (HRs) of fracture according to categories of S-25OHD. Our secondary exposures were serum 1,25-dihydroxycholecalciferol (1,25-(OH)₂ D₃ ), the most active vitamin D metabolite and plasma parathyroid hormone (P-PTH). During an average of 9.2 years of follow-up, 1080 women had a fracture. Women with S-25OHD <30 nmol/L drawn during sunny months (May-October) had a multivariable-adjusted fracture HR of 2.06 (95% CI, 1.27-3.35) compared with those with S-25OHD >60 nmol/L; those with S-25OHD 30-40 nmol/L had an HR of 1.59 (95% CI, 1.12-2.26). In contrast, S-25OHD drawn during November through April was unrelated to fracture risk. The increased risk with low sunny season S-25OHD was seen only among women with body mass index (BMI) ≥25 kg/m² or fat mass index (FMI) ≥9.8 kg/m² . High fat mass and low S-25OHD were independently related to lower S-1,25-dihydroxycholecalciferol, which itself predicted fracture risk with samples collected during the sunny season. Irrespective of season, P-PTH was unrelated to fracture risk. We conclude that S-25OHD is associated with fracture risk only if drawn during periods of seasonally high levels in women with a high BMI. These results have implications for the evaluation of vitamin D status and can explain the lack of effect seen with vitamin D supplementation in many fracture trials. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Basal Vitamin D Status and Supplement Dose Are Primary Contributors to Maternal 25-Hydroxyvitamin D Response to Prenatal and Postpartum Cholecalciferol Supplementation

BACKGROUND

Variability in the 25-hydroxyvitamin D [25(OH)D] response to prenatal and postpartum vitamin D supplementation is an important consideration for establishing vitamin D deficiency prevention regimens.

OBJECTIVES

We aimed to examine interindividual variation in maternal and infant 25(OH)D following maternal vitamin D supplementation.

METHODS

In a randomized trial of maternal vitamin D supplementation (Maternal Vitamin D for Infant Growth Trial), healthy pregnant women (n = 1300) received a prenatal cholecalciferol (vitamin D-3) dose of 0, 4200, 16,800, or 28,000 IU/wk from 17 to 24 wk of gestation followed by placebo to 6 mo postpartum. A fifth group received 28,000 IU cholecalciferol/wk both prenatally and postpartum. In a subset of participants, associations of 25(OH)D with hypothesized explanatory factors were estimated in women at delivery (n = 655) and 6 mo postpartum (n = 566), and in their infants at birth (n = 502) and 6 mo of age (n = 215). Base models included initial 25(OH)D and supplemental vitamin D dose. Multivariable models were extended to include other individual characteristics and specimen-related factors. The model coefficient of determination (R2) was used to express the percentage of total variance explained.

RESULTS

Supplemental vitamin D intake and initial 25(OH)D accounted for the majority of variance in maternal 25(OH)D at delivery and postpartum (R2 = 70% and 79%, respectively). Additional characteristics, including BMI, contributed negligibly to remaining variance (<5% increase in R2). Variance in neonatal 25(OH)D was explained mostly by maternal delivery 25(OH)D and prenatal vitamin D intake (R2 = 82%). Variance in 25(OH)D in later infancy could only partly be explained by numerous biological, sociodemographic, and laboratory-related characteristics, including feeding practices (R2 = 43%).

CONCLUSIONS

Presupplementation 25(OH)D and vitamin D supplemental dose are the major determinants of the response to maternal prenatal vitamin D intake. Vitamin D dosing regimens to prevent maternal and infant vitamin D deficiency should take into consideration the mean 25(OH)D concentration of the target population.

Sex and body mass index dependent associations between serum 25-hydroxyvitamin D and pulse pressure in middle-aged and older US adults

High pulse pressure (PP) is a valid indicator of arterial stiffness. Many studies have reported that vitamin D concentration is inversely associated with vascular stiffening. This association may differ depending on sex and body mass index (BMI). This study investigated the associations between vitamin D and PP and evaluated whether these associations differ according to sex and BMI, using data for individuals aged ≥ 50 years from the National Health and Nutrition Examination Survey (NHANES) 2007-2010. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were used as biomarkers of vitamin D levels. High PP was defined as ≥ 60 mmHg. Total 25(OH)D concentrations were dose-dependently associated with lower odds ratios (ORs) for high PP (p-trend = 0.01), after controlling for sociodemographic, behavioral, and dietary factors. When stratified by sex, there was a dose-dependent association between total 25(OH)D concentrations and lower risk of high PP (p-trend < 0.001) in females, but not in males. When stratified by BMI, there was a dose-dependent association between total 25(OH)D concentrations and lower risk of high PP (p-trend < 0.001) in non-overweight subjects, but not in overweight subjects. Improving the vitamin D status could delay elevation of PP and vascular stiffening in female and non-overweight subjects.

Response to single oral dose vitamin D in obese vs non-obese vitamin D-deficient children

Obese individuals are prone to vitamin D deficiency because of sequestration of vitamin D in their body fat. We planned to evaluate the rise in serum 25(OH)D levels in vitamin D-deficient obese vs normal body mass index(BMI) children, after administration of identical single dose of vitamin D. Twenty-two obese and 22 normal BMI children with serum 25 (OH)D < 20 ng/mL were given single oral dose 150,000 IU vitamin D, and 25 (OH)D levels were measured at 1 week and 1 month post-intervention. Results show that rise in 25(OH)D level from baseline was about 2.2 times lesser in obese compared with children with normal BMI, both at 1 week and at 1 month. The rise in 25(OH)D from baseline to 1 month was inversely correlated to BMI (r = - 0.56, p = < 0.001), waist circumference (r = - 0.48, p = 0.001), total fat mass (r = - 0.58, p < 0.001), and fat mass index (r = - 0.59, p < 0.001).Conclusion: The obese children have a 2.2 times lower rise in serum vitamin D levels as compared with the normal BMI children for the same dose of vitamin D supplementation. What is Known: • The obese individuals are prone to vitamin D deficiency and may be given higher doses of vitamin D supplementation. What is New: • Our study demonstrates that obese children have 2.2 times lesser rise in serum 25(OH)D concentrations as compared with normal BMI children when administered similar oral dose vitamin D.

Role of Vitamin D in the Metabolic Syndrome

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

Vitamin D and Sarcopenia: Potential of Vitamin D Supplementation in Sarcopenia Prevention and Treatment

Skeletal muscle, the largest organ in the human body, accounting for approximately 40% of body weight, plays important roles in exercise and energy expenditure. In the elderly, there is often a progressive decline in skeletal muscle mass and function, a condition known as sarcopenia, which can lead to bedridden conditions, wheelchair confinement as well as reducing the quality of life (QOL). In developed countries with aging populations, the prevention and management of sarcopenia are important for the improvement of health and life expectancy in these populations. Recently, vitamin D, a fat-soluble vitamin, has been attracting attention due to its importance in sarcopenia. This review will focus on the effects of vitamin D deficiency and supplementation on sarcopenia.

Disparities in Head and Neck Cancer: A Case for Chemoprevention with Vitamin D

Blacks experience disproportionate head and neck cancer (HNC) recurrence and mortality compared to Whites. Overall, vitamin D status is inversely associated to HNC pointing to a potential protective linkage. Although hypovitaminosis D in Blacks is well documented it has not been investigated in Black HNC patients. Thus, we conducted a prospective pilot study accessing vitamin D status in newly diagnosed HNC patients stratified by race and conducted in vitro studies to investigate mechanisms associated with potential cancer inhibitory effects of vitamin D. Outcome measures included circulating levels of vitamin D, related nutrients, and risk factor characterization as well as dietary and supplemental estimates. Vitamin D-based in vitro assays utilized proteome and microRNA (miR) profiling. Nineteen patients were enrolled, mean circulating vitamin D levels were significantly reduced in Black compared to White HNC patients, 27.3 and 20.0 ng/mL, respectively. Whites also supplemented vitamin D more frequently than Blacks who had non-significantly higher vitamin D from dietary sources. Vitamin D treatment of HNC cell lines revealed five significantly altered miRs regulating genes targeting multiple pathways in cancer based on enrichment analysis (i.e., negative regulation of cell proliferation, angiogenesis, chemokine, MAPK, and WNT signaling). Vitamin D further altered proteins involved in cancer progression, metastasis and survival supporting a potential role for vitamin D in targeted cancer prevention.

Vitamin D Supplementation in Laboratory-Bred Mice: An In Vivo Assay on Gut Microbiome and Body Weight

Saudi Arabia is in a tropical geographical region with a population that has access to adequate diet. There is, however, a high level of vitamin D deficiency in the Kingdom, comorbid with other disease. There is the postulation of a correlation between a healthy gut microbiota and balanced levels of serum vitamin D. This investigation looks into the effect of vitamin D supplementation on the gut flora of laboratory-bred mice as well as any possible association on body weight. BALB/C mice weighing between 34 and 35.8 g were divided into 4 groups and placed on daily doses of vitamin D of 3.75 µg (low dose), 7.5 µg (normal dose), and 15 µg (high dose). The fourth group was the control group that did not receive any supplementation with vitamin D. Body weights were monitored on weekly basis, while faecal samples from the rectum were obtained for microbial culturing and the monitoring of bacterial colony count using the Vitek 2 Compact automated system (BioMerieux, Marcy-l’Etoile, France) according to manufacturer’s guidelines. The data presented as mean ± SD, while significant differences were determined with 2-way analysis of variance in comparing differences within and between treatment groups. The different doses of vitamin D showed varying effects on the body weight and gut microbial colonies of the mice. There was a highly significant difference between the control, 15 µg (high), and 7.5 µg (normal) dose groups. This is suggestive that supplementation with vitamin D could a role in the gut microbial flora in the gut which could reflect in changes in body weight.

Visceral Fat Is a Negative Determinant of Bone Health in Obese Postmenopausal Women

The protective effect of obesity on bone health has been challenged by studies that link visceral adiposity to poor bone microarchitecture in young obese men and women. In postmenopausal women, the role of visceral adipose tissue (VAT) on bone turnover markers (BTMs) has not been investigated. The aim was to investigate the impact of VAT on BTMs, total bone mineral density (BMD), vitamin D metabolites and parathyroid levels (1-84 PTH) levels in postmenopausal women. A total of 76 lean and overweight women (without osteoporosis) underwent VAT measurements by dual-energy X-ray absorptiometry (iDXA). Blood samples were analyzed for serum C-terminal telopeptide of type 1 collagen (CTX-1), osteocalcin, bone-specific alkaline phosphatase (bone ALP), 1–84 PTH and vitamin D (25 hydroxyvitamin D, 25(OH)D) levels. VAT volumes ranged from 91 to 3392 cm³ and body mass index (BMI) ranged from 18.3 to 53.9 kg/m². Women in the highest VAT quartile had significantly lower CTX-1, 25(OH)D, osteocalcin and the highest BMD (p < 0.05, for all). While VAT positively associated with BMD, after controlling for BMI, VAT was a negative predictor of BMD (β = 0.368, p < 0.05). VAT was an independent negative predictor of CTX-1 (β = −0.263, p < 0.05) and osteocalcin levels (β = −0.277, p < 0.05). Among all measures of adiposity, VAT was the strongest independent determinant of BMD and BTMs. In clinical settings, VAT, and not BMI, may be a sensitive predictor of bone health in obese women.

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.

Genetic Components of 25-Hydroxyvitamin D Increase in Three Randomized Controlled Trials

The 25-Hydroxyvitamin D (25[OH)D) serum concentration depends on vitamin D intake, endogenous vitamin D production and genetic factors. The latter have been demonstrated in large genome-wide association studies indicating that single nucleotide polymorphisms (SNPs) in genes related to the vitamin D metabolism are as important for serum 25(OH)D levels as the influence of season. The mechanism on how these SNPs influence serum 25(OH)D levels are still unclear. The aim of the present study was to investigate the genetic effects of ten selected SNPs related to vitamin D metabolism on 25-hydroxyvitamin D increase (∆25(OH)D) after vitamin D supplementation in three randomized controlled trials. Genotypes of SNPs related to vitamin D metabolism were determined in 411 participants with 25(OH)D concentrations < 75 nmol/l receiving 20,000 IU cholecalciferol per week for 8 or 12 weeks after study inclusion. For the vitamin D receptor (VDR) rs10783219 polymorphism, the minor A-allele was associated with lower ∆25(OH)D values in the entire study population (p = 0.022), which was not consistent in all three cohorts when analysed separately. VDR rs10783219 might therefore be a genetic modulator of increasing 25-hydroxyvitamin D concentrations. Considering the wide-spread use of vitamin D supplementation, future large and well-designed randomized controlled trials (RCTs) should investigate the clinical impact of this polymorphism.

Targeted 25-hydroxyvitamin D concentration measurements and vitamin D3 supplementation can have important patient and public health benefits

Over the past two decades, many studies reported the benefits of higher 25-hydroxyvitamin D [25(OH)D] concentrations for nonskeletal effects. Researchers found significant benefits in reducing risk of acute respiratory tract infections, many types of cancer, type 2 diabetes mellitus, premature death, and adverse pregnancy and birth outcomes. In addition, 25(OH)D concentrations are low for various reasons in several categories of people, including the obese, those with dark skin living at higher latitudes, the elderly, and those who do not eat much eggs, fish, meat, or vitamin D fortified milk. Measuring 25(OH)D concentrations is one way to both increase the awareness of vitamin D's importance in maintaining good health and to encourage vitamin D supplementation or increased solar ultraviolet-B exposure to sustain well-being throughout life by reducing disease incidence. Although 20 ng/ml seems adequate to reduce risk of skeletal problems and acute respiratory tract infections, concentrations above 30 ng/ml have been associated with reduced risk of cancer, type 2 diabetes mellitus, and adverse pregnancy and birth outcomes. Thus, judicious testing of 25(OH)D concentrations could reduce disease incidence and make treatment expenditures more cost-effective.

Epigenetics Predicts Serum 25-Hydroxyvitamin D Response to Vitamin D3 Supplementation in African Americans

SCOPE

The effects of vitamin D₃ supplementations on circulating 25-hydroxyvitamin D [25(OH)D] are varied. The hypothesis that the baseline DNA methylation plays a role in the serum 25(OH)D response to vitamin D₃ supplementation is tested.

METHODS AND RESULTS

A randomized clinical trial is first conducted among 64 African Americans, who are randomly assigned to a placebo or a 16-week treatment of 600, 2000, and 4000 IU d^-1 of vitamin D₃ supplements. Expected serum 25(OH)D concentrations at posttest are estimated by intervention, age, gender, body mass index, baseline 25(OH)D concentrations, and seasonal variations. The 25(OH)D response is categorized into a high-response group when the actual 25(OH)D concentrations at posttest are higher than expected, and a low-response group otherwise. The 25(OH)D response is associated with baseline methylation levels of CYP family and VDR genes (raw p < 0.05). At a genome-wide level, the baseline methylation level of cg07873128 (OSBPL5) that regulates cholesterol balance and calcium homeostasis is higher in the low-response group (false discovery rate = 0.028).

CONCLUSIONS

The baseline methylation levels of CYP family and VDR modulate 25(OH)D response. In addition, the hypermethylation of cg07873128 at the baseline, which is located in the imprinted gene OSBPL5, may reduce the serum 25(OH)D response to vitamin D₃ supplementation.

The Association between Body Mass Index and Vitamin D Supplement Use among Adults in the United States

Background

Obesity has been consistently associated with lower 25-hydroxyvitamin D (25(OH)D) concentrations. BMI status also has a major impact on 25(OH)D levels among vitamin D supplement users. In our cross-sectional study, we aimed to discuss the prevalence of vitamin D supplement use and its effect on 25(OH)D levels according to BMI status among US adults.

Methods

The present analysis was based on data from the National Health and Nutrition Examination Survey (NHANES) cycles 2011-2012 through 2013-2014. The prevalence of vitamin D supplement use according to BMI status among subjects aged 20 years and older by selected characteristics was analyzed. Logistic regression models were assembled to examine the independent association of BMI status and vitamin D supplement use. Similarly, general linear models were used to assess the effect of daily vitamin D supplementation doses (<400 IU, 400-800 IU, and >800 IU) on 25(OH)D concentrations according to BMI status.

Results

Of 10,076 participants with a mean age of 47.2 [standard error (SE): 0.4] years, 57.5% (SE: 1.7) of normal-weight and 63.5% (SE: 0.9) of obese subjects reported not taking vitamin D supplements over the previous 30 days. After adjustment for potential confounders, obese subjects were 1.3 times more likely to be nonusers of vitamin D supplements and were 24% less likely to take vitamin D supplements ≥400 IU/day compared with their normal-weight counterparts. In addition, significant differences in mean 25(OH)D levels of vitamin D supplementation doses were consistently seen across BMI categories. Indeed, obese and overweight participants taking >800 IU/day of vitamin D supplements had 15.5 and 8.1 nmol/L lower mean concentrations of 25(OH)D than their normal-weight counterparts on average, respectively.

Conclusion

Obese subjects had a lower prevalence of vitamin D supplement use compared with their normal-weight counterparts. This nutritional disparity may also contribute to low 25(OH)D concentrations seen in obesity. However, a daily vitamin D supplement intake between 400 IU and 800 IU appears to be adequate among obese subjects to achieve optimal 25(OH) levels. 

Vitamin D Deficiency: Consequence or Cause of Obesity?

Obesity is defined as an excess amount of body fat and represents a significant health problem worldwide. High prevalence of vitamin D (VD) deficiency in obese subjects is a well-documented finding, most probably due to volumetric dilution into the greater volumes of fat, serum, liver, and muscle, even though other mechanisms could not completely be excluded, as they may contribute concurrently. Low VD could not yet be excluded as a cause of obesity, due to its still incompletely explored effects through VD receptors found in adipose tissue (AT). VD deficiency in obese people does not seem to have consequences for bone tissue, but may affect other organs, even though studies have shown inconsistent results and VD supplementation has not yet been clearly shown to benefit the dysmetabolic state. Hence, more studies are needed to determine the actual role of VD deficiency in development of those disorders. Thus, targeting lifestyle through healthy diet and exercise should be the first treatment option that will affect both obesity-related dysmetabolic state and vitamin D deficiency, killing two birds with one stone. However, VD supplementation remains a treatment option in individuals with residual VD deficiency after weight loss.

Obesity Decreases Hepatic 25-Hydroxylase Activity Causing Low Serum 25-Hydroxyvitamin D

Normal vitamin D homeostasis is critical for optimal health; nevertheless, vitamin D deficiency is a worldwide public health problem. Vitamin D insufficiency is most commonly due to inadequate cutaneous synthesis of cholecalciferol and/or insufficient intake of vitamin D, but can also arise as a consequence of pathological states such as obesity. Serum concentrations of 25(OH)D (calcidiol) are low in obesity, and fail to increase appropriately after vitamin D supplementation. Although sequestration of vitamin D in adipose tissues or dilution of ingested or cutaneously synthesized vitamin D in the large fat mass of obese patients has been proposed to explain these findings, here we investigate the alternative mechanism that reduced capacity to convert parent vitamin D to 25(OH)D due to decreased expression of CYP2R1, the principal hepatic vitamin D 25-hydroxylase. To test this hypothesis, we isolated livers from female mice of 6 to 24 weeks of age, weaned onto either a normal chow diet or a high-fat diet, and determined the abundance of Cyp2r1 mRNA using digital droplet-quantitative PCR. We observed a significant (p < 0.001) decrease in Cyp2r1 mRNA in the liver of high-fat diet-fed mice relative to lean-chow-fed female mice. Moreover, there was a significant (p < 0.01) relationship between levels of Cyp2r1 mRNA and serum 25(OH)D concentrations as well as between Cyp2R1 mRNA and the ratio of circulating 25(OH)D3 to cholecalciferol (p < 0.0001). Using linear regression we determined a curve with 25(OH)D3/cholecalciferol versus normalized Cyp2R1 mRNA abundance with an R2 value of 0.85. Finally, we performed ex vivo activity assays of isolated livers and found that obese mice generated significantly less 25(OH)D3 than lean mice (p < 0.05). Our findings indicate that expression of CYP2R1 is reduced in obesity and accounts in part for the decreased circulating 25(OH)D. © 2019 American Society for Bone and Mineral Research.

Waist circumference in relation to outcomes of infertility treatment with assisted reproductive technologies

BACKGROUND

Many studies have documented a lower likelihood of live birth with increasing body mass index among women undergoing assisted reproductive technology, but few have examined the association with waist circumference, an anthropometric measure that allows assessment of central adiposity.

OBJECTIVE

To examine the relation between baseline waist circumference and infertility treatment outcomes among women undergoing treatment with assisted reproductive technology.

MATERIALS AND METHODS

We followed up 264 women who underwent 445 assisted reproductive technology cycles for infertility treatment at the Massachusetts General Hospital between 2010 and 2017. Waist circumference was assessed at enrollment. We used cluster-weighted generalized estimating equation models to estimate the probability of live birth by tertiles of waist circumference (<77, 77-86, >86 cm), while accounting for multiple treatment cycles per woman and adjusting for age, race, smoking, infertility diagnosis, day 3 follicle-stimulating hormone, body mass index, and height.

RESULTS

Mean (standard deviation) waist circumference and body mass index were 83.6 (12.6) cm and 24.1 (4.3) kg/m², respectively. Waist circumference and body mass index were positively correlated (r = 0.69, P < .0001). Waist circumference was inversely related to the probability of live birth after adjusting for BMI and other confounders. The multivariable adjusted probability of live birth (95% confidence interval) for women in increasing tertiles of waist circumference were 53% (42-65%), 42% (32-53%), and 38% (28-50%) (P, trend = .04). When women were classified in joint categories of body mass index and waist circumference, women with a body mass index ≥25 kg/m² and a waist circumference ≥77 cm had the lowest live birth rate (38% [27-50%]), whereas women with a body mass index between 18.5 and 25 kg/m² and a waist circumference <77 cm had the highest (54% [42-66%]). The results were similar using different waist circumference cut-off values.

CONCLUSION

Waist circumference was inversely related to the probability of live birth among women undergoing assisted reproductive technology independently of body mass index.

Effect of weight loss on bone metabolism in postmenopausal obese women with osteoarthritis

BACKGROUND

The choice of hypocaloric diets in obesity can affect bone health.

AIMS

The aim of this study is to assess the effect of a hypocaloric diet in postmenopausal obese women and to determine the influence of weight reduction on bone metabolism.

METHODS

This was a non-randomised, single-treatment study in 96 postmenopausal women with a body mass index (BMI) greater than 35kg/m² and osteoarthritis. The patients received a formula diet with two intake levels of a normocaloric hyperproteic formula (1035kcal (25% protein)). Anthropometry and biochemistry with CrossLaps, osteocalcin, parathyroid hormone (PTH) and 25-OH vitamin D were measured. Consumption of protein, calcium and vitamin D were determined at the beginning of and 3 and 6 months into the study. The response to treatment was compared (high-responder (HR): weight loss greater than 15%, and low-responder (LR): weight loss less than 15%).

RESULTS

The mean age was 64.2 (7.5) years. After 6 months of treatment, a weight loss of 10.2% (8.2-13.8) was observed. There was a significant increase in vitamin D (HR: 21.8% (36.2) vs. LR: 22.7% (36.9), p=0.93) and CrossLaps (HR: 26.8% (19.5-35.2)) vs. LR: 13.3% (-6.1 to 27.9), p=0.01). The loss of more than 15% of initial body weight was an independent risk factor for an increase in CrossLaps (OR: 4.22 (1.1-16.8), p=0.04).

CONCLUSIONS

In postmenopausal obese women, weight loss was associated with an increase in the biochemical parameters of bone resorption. The increase in resorption parameters was related to the magnitude of weight loss.