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

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.

The association between vitamin D deficiency and childhood obesity and its impact on children's serum calcium, alkaline phosphatase, and bone age

OBJECTIVE

The research aimed to investigate the Association between Vitamin D deficiency and childhood obesity and its Impact on children's serum calcium, alkaline Phosphatase, and bone Age.

METHODS

The study analyzed clinical data from 159 school-aged children who underwent medical examinations. The children were divided into a 25-(OH)D3 deficiency group and a non-25-(OH)D3 deficiency group based on their serum 25-hydroxy Vitamin D3 levels. The two groups were compared regarding BMI, TC, TG, FBG, HbA1c, Ca, ALP, and bone age differences.

RESULTS

Individuals with a deficiency in 25-(OH)D3 exhibited higher levels of BMI, TC, TG, and ALP, and lower levels of Ca and bone age than those without the deficiency. These differences were statistically significant (P<0.05). Further analysis revealed a negative association between 25-(OH)D3 levelsa positive correlation between Ca and bone age, and a positive correlation with, BMI, TC, TG, and ALP.

CONCLUSION

The deficiency of 25-(OH)D3 in school-aged children is linked to obesity and impacts bone growth. Monitoring vitamin D levels is crucial for clinical practitioners.

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.

IGF1 Genetic Polymorphism and the Association between Vitamin D Status and BMI Percentiles in Children

Both the IGF1 axis and hypovitaminosis D play a role in childhood obesity, either as a cause or a causality. While some studies suggest an interrelation between vitamin D status, IGF1, and obesity, this mechanism remains obscure. The aim of this study, therefore, was to explore associations between four genetic polymorphisms in the IGF1 axis in hypovitaminosis D-related obesity. The study included 116 pre-pubertal Israeli Arab children (52 girls), mean age 9.4 ± 2.6. Serum 25(OH)D was measured and anthropometric measures were obtained. Genomic DNA was extracted from peripheral EDTA-treated anti-coagulated blood using a standard protocol. Genotypes were determined using the Taqman allelic discrimination assay. The IGF genetic score was computed according to the additive genetic score model. A moderate-to-high negative correlation (r = 0.580, p < 0.05) was seen between the vitamin D status and body mass index (BMI) percentile of participants with high GS. Yet, no correlations were seen between vitamin D status and BMI percentile for participants with a low-to-moderate genetic score (GS) (GS ≤ 2). These results suggest that IGF1 genetic scores associated with elevated circulating IGF1 may indicate a tendency toward developing hypovitaminosis D-associated obesity.

Precision Nutrition: The Hype Is Exceeding the Science and Evidentiary Standards Needed to Inform Public Health Recommendations for Prevention of Chronic Disease

As dietary guidance for populations shifts from preventing deficiency disorders to chronic disease risk reduction, the biology supporting such guidance becomes more complex due to the multifactorial risk profile of disease and inherent population heterogeneity in the diet-disease relationship. Diet is a primary driver of chronic disease risk, and population-based guidance should account for individual responses. Cascading effects on evidentiary standards for population-based guidance are not straightforward. Precision remains a consideration for dietary guidance to prevent deficiency through the identification of population subgroups with unique nutritional needs. Reducing chronic disease through diet requires greater precision in (a) establishing essential nutrient needs throughout the life cycle in both health and disease; (b) considering effects of nutrients and other food substances on metabolic, immunological, inflammatory, and other physiological responses supporting healthy aging; and (c) considering healthy eating behaviors. Herein we provide a template for guiding population-based eating recommendations for reducing chronic diseases in heterogenous populations.

The effect of maternal vitamin D deficiency during pregnancy on glycolipid metabolism of offspring rats and the improvement of vitamin D intervention after weaning

Background

Vitamin D deficiency during pregnancy is common, but whether maternal vitamin D status affects glycolipid metabolism of offspring remains unclear.

Objective

To evaluate the effect of maternal vitamin D deficiency during pregnancy on the glycolipid metabolism of offspring at different life-cycles (from birth to adulthood) and to explore the improvement of different dosages of vitamin D supplementation.

Methods

Sprague-Dawley rats were fed vitamin D-deprived (VDD group) or standard vitamin D diets (SC group) during pregnancy, and their diets were changed to standard vitamin D diets during lactation (the offspring were sorted into VDDoffspring and SCoffspring groups). After weaning, rats in the VDDoffspring group were randomly assigned to the VDDoffspring, VDDoffspring-S3300 and VDDoffspring-S10000 groups with diets containing standard, medium and high dosages of vitamin D for 12 wk. Serum was collected for biochemical analyses at postnatal Day 21, postnatal Day 56 and postnatal Day 84. Oral glucose tolerance test (OGTT) was performed at postnatal Day 70.

Results

Compared to SCoffspring, rats in the VDDoffspring group had significantly lower birth weight with faster weight gain and higher levels of lipid metabolism in early life. After near adulthood, the differences in weight and lipid metabolism between the two groups disappeared. OGTT showed significantly higher blood glucose levels in the VDDoffspring group at 30 min, 60 min, and 90 min. The continuation of vitamin D supplementation at medium and high dosages after weaning did not cause any obvious changes in weight or glycolipid metabolism (except for postprandial hyperglycemia). OGTT demonstrated that the glucose levels in the VDDoffspring-S3300 group were lowest at all the time points and that those in the VDDoffspring-S10000 group were the highest at 30 min, 60 min, and 90 min among the three groups.

Conclusion

The adverse effects of vitamin D deficiency during pregnancy on glycolipid metabolism in offspring vary in different stages. Over a long time period, adequate vitamin D supplementation is beneficial to glycolipid metabolism for the offspring of subjects with vitamin D deficiency during pregnancy; however, further improvement is required.

Systemic and Oral Health Parameters in Eutrophic and Overweight/Obese Adolescents: A Cross-Sectional Study

To date, studies focusing on oral health in obese adolescents have provided controversial data. The aim of this cross-sectional study was to investigate systemic and oral health parameters in eutrophic and overweight/obese adolescents. In total, 100 adolescents, mean aged 13.33 ± 2.04 years, were divided into two groups: 59 overweight/obese adolescents in the study group (SG) and 41 eutrophic-weight adolescents in the control group (CG). Chi-squared and Fisher exact tests were performed to compare dichotomous and categorical variables between the two groups. The subjects in the SG (mean aged 13.21 ± 2.21) reported a body mass index (BMI) of 29.05 ± 4.09 kg/m², corresponding to over 95° percentile for both genders, and the subjects in the CG (mean aged 13.49 ± 1.77) reported a BMI of 18.26 ± 4.81 kg/m², corresponding to 25° percentile for both genders. In the SG, the serum level of 25-hydroxy-vitamin D was significantly lower (p-value < 0.001), whereas fasting blood glucose (p = 0.006), waist circumference, and hip circumference were significantly higher (p-value < 0.001). Plaque Index (PI), Plaque Control Record (PCR), Oral Hygiene Index (OHI), Gingival Index (GI), and Gingival bleeding index (GBI) depicted a significantly worse level of oral health in the SG. Moreover, the number of subjects with caries was significantly higher in the SG. Nutritional and physical activity status according to the Mediterranean Diet Quality Index for children and teenagers (KIDMED test) and the International Physical Activity Questionnaire (IPAQ-Adolescent) were reported to be significanlty better in the CG. In light of our results, obesity and poor oral health coexist in a cohort of adolescents. A screening of oral health status should be considered in obese subjects to focus resources on therapeutic interventions aiming at improving oral health.

Serum 25-Hydroxyvitamin D Levels and Youth-Onset Type 2 Diabetes: A Two-Sample Mendelian Randomization Study

Observational studies have linked vitamin D insufficiency to pediatric type 2 diabetes (T2D), but evidence from vitamin D supplementation trials is sparse. Given the rising prevalence of pediatric T2D in all ethnicities, determining the protective role of vitamin D has significant public health importance. We tested whether serum 25-hydroxyvitamin D (25OHD) levels are causally linked to youth-onset T2D risk using Mendelian randomization (MR). We selected 54 single-nucleotide polymorphisms (SNPs) associated with 25OHD in a European genome-wide association study (GWAS) on 443,734 individuals and obtained their effects on pediatric T2D from the multi-ethnic PRODIGY GWAS (3006 cases/6061 controls). We applied inverse variance weighted (IVW) MR and a series of MR methods to control for pleiotropy. We undertook sensitivity analyses in ethnic sub-cohorts of PRODIGY, using SNPs in core vitamin D genes or ancestry-informed 25OHD SNPs. Multivariable MR accounted for the mediating effects of body mass index. We found that a standard deviation increase in 25OHD in the logarithmic scale did not affect youth-onset T2D risk (IVW MR odds ratio (OR) = 1.04, 95% CI = 0.96-1.13, p = 0.35) in the multi-ethnic analysis, and sensitivity, ancestry-specific and multivariable MR analyses showed consistent results. Our study had limited power to detect small/moderate effects of 25OHD (OR of pediatric T2D < 1.39 to 2.1). In conclusion, 25OHD levels are unlikely to have significant effects on the risk of youth-onset T2D across different ethnicities.