Daily vitamin D3 in overweight and obese children and adolescents: a randomized controlled trial

The "Burden" of Childhood Obesity on Bone Health: A Look at Prevention and Treatment

Childhood obesity represents a multifaceted challenge to bone health, influenced by a combination of endocrine, metabolic, and mechanical factors. Excess body fat correlates with an increase in bone mineral density (BMD) yet paradoxically elevates fracture risk due to compromised bone quality and increased mechanical loading on atypical sites. Additionally, subjects with syndromic obesity, as well as individuals with atypical nutritional patterns, including those with eating disorders, show bone fragility through unique genetic and hormonal dysregulations. Emerging evidence underscores the adverse effects of new pharmacological treatments for severe obesity on bone health. Novel drugs, such as glucagon-like peptide-1 (GLP-1) receptor agonists, and bariatric surgery demonstrate potential in achieving weight loss, though limited evidence is available regarding their short- and long-term impacts on skeletal health. This review provides a comprehensive analysis of the mechanisms underlying the impact of childhood obesity on bone health. It critically appraises evidence from in vitro studies, animal models, and clinical research in children with exogenous obesity, syndromic obesity, and eating disorders. It also explores the effects of emerging pharmacological and surgical treatments for severe obesity on skeletal integrity, highlights prevention strategies, and identifies research gaps.

Optimal vitamin D supplement dosage for improving insulin resistance in children and adolescents with overweight/obesity: a systematic review and network meta-analysis

PURPOSE

We conducted a network meta-analysis which aims to evaluate the comparative efficacy of different supplementation dosages of vitamin D on cardiometabolic and bone-metabolic indicators as well as insulin resistance in children and adolescents with overweight/obesity.

METHODS

Eligible studies published before December 10, 2022 were retrieved from PubMed, EMBASE, Cochrane Library, and Web of Science. Mean difference and 95% confidence interval (CI) were used to express pooled estimates. Network meta-analysis of multiple doses, including low (< 1000 IU/day, LDS), medium (1000-2000 IU/day, MDS), high (2000-4000 IU/day, HDS), and extremely high (> 4000 IU/day, EHDS) dosage strategy, was conducted using STATA/MP 14.0.

RESULTS

Our network meta-analysis of 15 RCTs suggested that, compared with placebo and LDS, EHDS was increased 25-(OH)-D, with a pooled MD of 8.65 (95% CI 4.72-12.58) and 7.66 (95% CI 0.91-14.41), respectively. Meanwhile, EHDS also decreased ho meostasis model assessment-insulin resistance (HOMA-IR) (MD: - 0.74; 95% CI: - 1.45 to - 0.04) and C-reactive protein (CRP) (MD: - 18.99; 95% CI - 21.60 to - 16.38), and EHDS was also better than LDS (MD: - 18.47; 95% CI - 20.66 to - 16.28) and MDS (MD: - 19.69; 95% CI - 22.17 to - 17.21) in decreasing CRP. Ranking probability suggested that EHDS ranked best for increasing 25-(OH)-D, and decreasing HOMA-IR and CRP, with a probability of 86.1%, 83.1%, and 76.6%, respectively.

CONCLUSIONS

The results of our network meta-analysis suggest that EHDS may be the best strategy for vitamin D supplementation to reduce inflammatory responses as well as improve insulin resistance in children and adolescents with overweight/obesity.

PROSPERO REGISTRATION NUMBER

CRD42023387775.

Scientific opinion on the tolerable upper intake level for vitamin D, including the derivation of a conversion factor for calcidiol monohydrate

Following two requests from the European Commission (EC), the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the revision of the tolerable upper intake level (UL) for vitamin D and to propose a conversion factor (CF) for calcidiol monohydrate into vitamin D3 for labelling purposes. Vitamin D refers to ergocalciferol (vitamin D2), cholecalciferol (vitamin D3), and calcidiol monohydrate. Systematic reviews of the literature were conducted to assess the relative bioavailability of calcidiol monohydrate versus vitamin D3 on serum 25(OH)D concentrations, and for priority adverse health effects of excess vitamin D intake, namely persistent hypercalcaemia/hypercalciuria and endpoints related to musculoskeletal health (i.e. falls, bone fractures, bone mass/density and indices thereof). Based on the available evidence, the Panel proposes a CF for calcidiol monohydrates of 2.5 for labelling purposes. Persistent hypercalciuria, which may be an earlier sign of excess vitamin D than persistent hypercalcaemia, is selected as the critical endpoint on which to base the UL for vitamin D. A lowest-observed-adverse-effect-level (LOAEL) of 250 μg/day is identified from two randomised controlled trials in humans, to which an uncertainty factor of 2.5 is applied to account for the absence of a no-observed-adverse-effect-level (NOAEL). A UL of 100 μg vitamin D equivalents (VDE)/day is established for adults (including pregnant and lactating women) and for adolescents aged 11-17 years, as there is no reason to believe that adolescents in the phase of rapid bone formation and growth have a lower tolerance for vitamin D compared to adults. For children aged 1-10 years, a UL of 50 μg VDE/day is established by considering their smaller body size. Based on available intake data, European populations are unlikely to exceed the UL, except for regular users of food supplements containing high doses of vitamin D.

Effect of Vitamin D Supplementation on (25(OH)D) Status in Children 12-30 Months of Age: A Randomized Clinical Trial

Vitamin D (VD) deficiency (serum 25(OH)D < 50 nmol/L) affects 27.3% of preschool children in Mexico. The purpose of this study was to assess the effect of vitamin D supplementation at different doses on serum 25(OH)D concentrations in preschool children. In a randomized control trial, 222 children 12-30 months old were randomly assigned to one of four treatment groups: (1) Vitamin D2 (Ergocalciferol) 400 IU/day (n = 56); (2) Vitamin D2 (Ergocalciferol) 800 IU/day (n = 55); (3) Vitamin D3 (Cholecalciferol) 1000 IU/day (n = 56); or (4) multiple micronutrients (MM) non-VD (n = 55). Supplements were given five days/wk for three months. Serum 25(OH)D was measured at baseline and after three months. At baseline, mean serum 25(OH)D was 58.9 ± 12.6 nmol/L and 23.4% were VD-deficient. There was a statistically significant increase in serum concentrations of 25(OH)D (range across groups: +8.2 to +17.3 nmol/L). Additionally, the prevalence of vitamin D deficiency decreased after three months: for D2 400 IU, -9.0%; for D2 800 IU, -11.0%; for D3 1000 IU, -18.0%; and for MM non-VD, -2.8% (p < 0.05). No adverse effects were observed. VD supplementation for three months was effective for increasing serum 25(OH)D concentrations and for reducing VD deficiency in preschool children. The highest efficacy was observed by giving 1000 IU D3/d.

Effects of vitamin D supplementation in obese and overweight children and adolescents: a systematic review and meta-analysis

Due to the lipophilic nature of vitamin D, overweight and obese patients have an increased risk of inadequate circulating 25-hydroxy-vitamin D (25(OH)D) concentrations. Vitamin D deficiency has in turn several consequences especially among children and adolescents. Therefore, a few supplementation strategies of vitamin D for pediatric subjects with an excessive body weight have been proposed, but their efficacy remains controversial. The aim of this systematic review and meta-analysis is to evaluate the effect of vitamin D supplementation in overweight and obese children and adolescents. Three databases (PubMed, Embase and Web of Science) were searched to collect randomized controlled trials on the effect of vitamin D supplementation in the pediatric overweight or obese population. Twenty-three studies were included in the systematic review. Results on modification of metabolic or cardiovascular outcomes were controversial. On the other hand, the meta-analysis showed a mean difference by 1.6ng/mL in subjects supplemented with vitamin D as compared to placebo. In conclusion, vitamin D supplementation slightly increases 25(OH)D levels in pediatric subjects with overweight and obesity. However, the effects on metabolic and cardiovascular outcomes remain controversial. New efforts should be devoted to promoting effective interventions to improve the health of children and adolescents with overweight and obesity.

Efficacy of vitamin D supplementation on child and adolescent overweight/obesity: a systematic review and meta-analysis of randomized controlled trials

The global prevalence of overweight and obesity in children and adolescents has been increasing. Child and adolescent overweight/obesity has been demonstrated to be partially associated with vitamin D deficiency. This systematic review and meta-analysis aims to assess the efficacy of vitamin D supplementation on child and adolescent overweight/obesity. PubMed, Embase, Cochrane Library, and Web of science were searched from inception to June 20th, 2022. Randomized controlled trials (RCTs) assessing the efficacy of vitamin D on child and adolescent overweight/obesity were included. The Cochrane bias risk assessment tool was used to assess the bias risk of included studies, and subgroup analysis was conducted based on different administration dosages. All data-analyses were performed using R 4.2.1. There were 1502 articles retrieved, and 10 eligible studies were finally included, with a total of 595 participants. Meta-analysis showed no differences in LDL, TC, TG, BMI, ALP, Ca, and PTH between vitamin-D (Vit-D) group and placebo, while Vit-D group resulted in improved HOMA-IR[WMD =  - 0.348, 95%CI (- 0.477, - 0.219), p = 0.26]. Subgroup-analysis showed no significant difference in the increase of 25-(OH)-D between subgroups (p = 0.39), whereas the serum 25-(OH)-D level was increased under different Vit-D doses [WMD = 6.973, 95%CI (3.072, 10.873)]. High daily dose (≥ 4000 IU/d) of Vit-D might decrease CRP and increase HDL levels.   Conclusion: High dose of Vit-D supplementation (over 4000 IU/d) would reduce several cardiometabolic risk indicators and improve insulin resistance. More high-quality and large-scale RCTs are needed to provide more robust evidence. What is Known: • Vit-D deficiency is common in overweight/obesity (OW/OB) children and adolescents. • Previous randomized studies on the benefit of Vit-D supplementation to OW/OB children and adolescents are inconsistent. What is New: • This is the first meta-analysis conducted to assess the efficacy of Vit-D supplementation on child and adolescent OW/OB. • High dose of Vit-D supplementation is beneficial to cardiovascular metabolism, and improve insulin resistance on child and adolescent OW/OB.

Impact of daily vitamin D3 supplementation on the risk of vitamin D deficiency with the interaction of rs2282679 in vitamin D binding protein gene (GC) among overweight and obese children and adolescents: A one-year randomized controlled trial

Background

The rs2282679 polymorphism in the vitamin D binding protein (DBP) gene may influence the response to vitamin D supplementation. Therefore, we examine the effect of 1-year vitamin D supplementation on vitamin D deficiency (VDD) with the interaction of rs2282679 polymorphism in overweight and obese children and adolescents.

Materials and methods

The participants (n = 300) were part of a randomized controlled trial who received a daily supplement of either 1,000 or 2,000 IU or four supplements of 1,000 IU weekly (equal to 600 IU daily) of vitamin D₃ for 12 months. Genotyping was performed using amplification refractory mutation system polymerase chain reaction (ARMS-PCR).

Results

The mean of 25(OH)D values at baseline for participants with the TT, TG, and GG genotypes were 15.4, 14.4, and 10.8 ng/mL, respectively, and were not different between the three genotype groups (P = 0.062). A significant reduction in VDD was observed after vitamin D supplementation with dosages of 1,000 or 2,000 IU compared to 600 IU. No significant association of genotypes with risk of VDD was observed in each intervention group after vitamin D supplementation, except, that individuals with TG genotype showed a higher risk of VDD compared to those with TT genotype in the 2,000 IU group after 6 months of supplementation [odds ratio (95% CI): 6.94; 1.30-37.02]. We observed no interaction between time duration, three genotypes, and dosages with serum 25(OH)D, calcium, phosphorus, alkaline phosphatase, and parathyroid hormone levels.

Conclusion

Response to vitamin D supplementation by three doses of 600, 1,000, and 2,000 IU could not be affected by rs2282679 polymorphism during 12 months in overweight and obese children and adolescents.

Drug dosing in children with obesity: a narrative updated review

Childhood obesity and its associated comorbidities are highly prevalent diseases that may add to any other possible health problem commonly affecting the pediatric age. Uncertainties may arise concerning drug dosing when children with obesity need pharmacologic therapies. In general, in pediatric practice, there is a tendency to adapt drug doses to a child's total body weight. However, this method does not consider the pharmacological impact that a specific drug can have under a two-fold point of view, that is, across various age and size groups as well. Moreover, there is a need for a therapeutic approach, as much as possible tailored considering relevant interacting aspects, such as modification in metabolomic profile, drug pharmacokinetics and pharmacodynamics. Taking into account the peculiar differences between children with overweight/obesity and those who are normal weight, the drug dosage in the case of obesity, cannot be empirically determined solely by the per kg criterion. In this narrative review, we examine the pros and cons of several drug dosing methods used when dealing with children who are affected also by obesity, focusing on specific aspects of some of the drugs most frequently prescribed in real-world practice by general pediatricians and pediatric subspecialists.

Adiposity Metabolic Consequences for Adolescent Bone Health

Infancy and adolescence are crucial periods for bone health, since they are characterized by intense physical growth and bone development. The unsatisfactory acquisition of bone mass in this phase has consequences in adult life and increases the risk of developing bone diseases at more advanced ages. Nutrient deficiencies, especially calcium and vitamin D, associated with a sedentary lifestyle; lack of sun exposure; and epigenetic aspects represent some of the main risk factors for poor bone quality. In addition, recent studies relate childhood obesity to impaired bone health; however, studies on the adiposity effects on bone health are scarce and inconclusive. Another gap concerns the implications of obesity on child sexual maturity, which can jeopardize their genetic potential bone mass and increase fracture risk. Therefore, we reviewed the analyzed factors related to bone health and their association with obesity and metabolic syndrome in adolescents. We concluded that obesity (specifically, accumulated visceral fat) harms bones in the infant-juvenile phase, thereby increasing osteopenia/osteoporosis in adults and the elderly. Thus, it becomes evident that forming and maintaining healthy eating habits is necessary during infancy and adolescence to reduce the risk of fractures caused by bone-metabolic diseases in adulthood and to promote healthy ageing.

Hypertension in obese children is associated with vitamin D deficiency and serotonin dysregulation

Background

Obesity and hypertension represent serious health issues affecting the pediatric population with increasing prevalence. Hypovitaminosis D has been suggested to be associated with arterial hypertension. Serotonin by modulating nitric oxide synthase affect blood pressure regulation. The biological mechanism by which vitamin D specifically regulates serotonin synthesis was recently described. The aim of this paper is to determine the associations between vitamin D, serotonin, and blood pressure in obese children.

Methods

One hundred and seventy-one children were enrolled in the prospective cross-sectional study. Two groups of children divided according to body mass index status to obese (BMI ≥95th percentile; n = 120) and non-obese (n = 51) were set. All children underwent office and ambulatory blood pressure monitoring and biochemical analysis of vitamin D and serotonin. Data on fasting glucose, insulin, HOMA, uric acid, and complete lipid profile were obtained in obese children.

Results

Hypertension was found only in the group of obese children. Compared to the control group, obese children had lower vitamin D and serotonin, especially in winter. The vitamin D seasonality and BMI-SDS were shown as the most significant predictors of systolic blood pressure changes, while diastolic blood pressure was predicted mostly by insulin and serotonin. The presence of hypertension and high-normal blood pressure in obese children was most significantly affected by vitamin D deficiency and increased BMI-SDS.

Conclusions

Dysregulation of vitamin D and serotonin can pose a risk of the onset and development of hypertension in obese children; therefore, their optimization together with reducing body weight may improve the long-term cardiovascular health of these children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03337-8.

Effect of Vitamin D and Docosahexaenoic Acid Co-Supplementation on Vitamin D Status, Body Composition, and Metabolic Markers in Obese Children: A Randomized, Double Blind, Controlled Study

Obese children are at high risk of developing vitamin D deficiency. Omega-3 polyunsaturated fatty acids and their derivatives might have a beneficial effect on vitamin D status of obese children, due to their anti-inflammatory action, and increasing its absorption. This multicenter, randomized, double-blind controlled study aims to investigate the effect of vitamin D and docosahexaenoic acid (DHA) co-supplementation for six months on vitamin D status, body composition, and metabolic markers of obese children with vitamin D deficiency. A total of 108 children were enrolled and 73 children completed the study: 33 were supplemented with an oral dose of 500 mg of DHA and 1200 IU/day of vitamin D3 and 41 were supplemented with 1200 IU/day of vitamin D3 + wheat germ oil. At the end of the study, more than 50% of the subjects improved their vitamin D status. However, co-supplementation was not more effective than vitamin D plus wheat germ oil. Fat mass percentage was significantly reduced, and body mass index improved in both groups, even if all the subjects were still obese at the end of the study. Children receiving both vitamin D and DHA presented a higher increase of DHA levels that could be relevant to prevent inflammatory-associated complications of obesity, but they had no effect on vitamin D levels.