Assessment of vitamin D status and parathyroid hormone during a combined intervention for the treatment of childhood obesity

Antioxidant Supplementation in Childhood Obesity: A Path to Improved Metabolic Health?

Childhood obesity is linked to heightened oxidative stress, a key driver of endothelial dysfunction, inflammation, and metabolic complications. Antioxidants, including Vitamins C and E, are vital in neutralizing free radicals and mitigating oxidative damage. This non-systematic review examines the potential advantages of antioxidant supplementation in pediatric obesity, focusing on its effects on vascular health, insulin sensitivity, and inflammatory processes. Emerging data suggest that antioxidants may improve endothelial function, reduce blood pressure, and enhance metabolic homeostasis in obese children. However, the long-term efficacy and safety of antioxidant supplementation remain uncertain, necessitating further rigorous randomized controlled trials. A deeper understanding of antioxidants' role in pediatric obesity could unlock novel therapeutic approaches for managing obesity-related complications and improving children's overall health outcomes.

Physical activity and vitamin D in children: a review of impacts on bone health and fitness

OBJECTIVES

This review explores the relationship between physical activity and serum 25-hydroxyvitamin D (25(OH)D) levels in children and adolescents, highlighting the importance of vitamin D for bone health and muscle function.

CONTENT

A narrative mini review was conducted by searching PubMed, Google Scholar, and Scopus for studies published from January 2000 to April 2024, focusing on children aged 5-18 years. Ten studies were reviewed, including five cross-sectional, three population-based, one longitudinal, and one randomized controlled trial. Overall, physically active children and teens were more likely to maintain sufficient 25(OH)D levels and demonstrated better physical fitness, especially in muscle strength, compared to their less active peers. One study linked higher vitamin D levels to increased bone mineral content in active adolescents, while another reported a positive connection between vitamin D and bone density. Risk factors for deficiency included limited sun exposure, low physical activity, sedentary behavior, and obesity, with the latter group being more prone to low vitamin D levels, which were negatively associated with fat mass. Interventions that increased physical activity were found to improve vitamin D levels.

SUMMARY AND OUTLOOK

Regular physical activity, especially outdoor exercise, is associated with healthier vitamin D levels in children, supporting better bone health and physical fitness.

Are sun exposure time, dietary patterns, and vitamin D intake related to the socioeconomic status of Portuguese children?

OBJECTIVES

To investigate the association among sun exposure time, vitamin D intake, dietary patterns, and socioeconomic status in Portuguese children.

METHODS

Participants aged 3-11 years (50.1% females) were recruited from public and private schools (n = 118) in the districts of Coimbra (n = 2980), Lisbon (n = 3066), and Porto (n = 2426). Parents reported their children's daily sun exposure time during the summer season and reported children's food consumption, including vitamin D food sources, using standardized questionnaires. Parents' education level was used as a proxy measure to the socioeconomic status (SES). The principal component factor analysis (PCA) method was used to identify dietary patterns. The eight dietary patterns identified were labeled in: "fast food", "rich in vitamin D", "sugary drinks", "vitamin D", "candies", "supplements", "rich in calcium" and "vegetables/healthy". Linear regression analyses were performed to investigate the association between sun exposure time and dietary patterns according to SES.

RESULTS

A total of 4755 children were included. Children from high SES had significantly longer sun exposure time (p < .001) and more frequently consumed vitamin D supplements (p < .001). "Fast food" pattern showed a negative association with sun exposure time in medium and high SES (p = .014 and p < .001, respectively).

CONCLUSION

Children with lower SES spend less time exposed to the sun, consume fewer dietary sources of vitamin D, and consume more foods rich in fat and sugar.

Childhood obesity and central precocious puberty

Central precocious puberty (CPP) is an endocrine disorder in children caused by the early activation of the hypothalamic-pituitary-gonadal axis (HPGA), leading to elevated gonadotropin-releasing hormone (GnRH), which triggers the development of gonads and the secretion of sex hormones. This eventually results in the development of internal and external genitalia and secondary sexual characteristics. CPP significantly affects the physical and mental health of children and may increase the risk of various adult diseases. The influencing factors and mechanisms of CPP are a central focus of research, and its prevention and treatment remain challenging. Childhood obesity is an important risk factor for CPP, with a complex relationship influenced by endocrine-disrupting chemicals, genetic factors, and epigenetic regulation. The link between the two is primarily related to the regulation of HPGA function by nutritional and metabolic signals. Exploring the relationship between childhood obesity and CPP, along with the potential mechanisms by which obesity induces CPP, can provide theoretical references for identifying new therapeutic targets.

Longitudinal analysis of vitamin D levels considering sunshine duration and suggestion for a standardised approach for vitamin D supplementation in children and adolescents with obesity

BACKGROUND

Children with obesity have low 25 hydroxy-vitamin D (25-OH-D3) levels compared to lean children. Recommendations on when to start vitamin D supplementation differ largely between countries. Longitudinal data on 25-OH-D3 levels to guide treatment decisions are scarce since they are largely influenced by solar radiation and are difficult to compare.

METHODS

We carried out a retrospective analysis of multiple 25-OH-D3 and parathyroid hormone (PTH) measurements in a cohort of 543 patients without vitamin D supplementation. All measurements were taken at the local paediatric obesity clinic as documented in the German-Austrian-Swiss APV (Prospective Documentation of Overweight Children and Adolescents) registry from 2009 to 2019. Serial 25-OH-D3 and PTH levels were adjusted for sunshine duration over the last 30 days to account for seasonal variation, as well as for sex and body mass index (BMI). We further performed an exploratory analysis of the association of sunshine duration, sex, BMI SDS (standard deviation score), abnormal lipid levels or dysglycemia with the 25-OH-D3 trend.

RESULTS

229 obese patients (mean BMI SDS: 2,58 (± 0,56), 53% females, mean age: 12 (± 3) years, range: 2-21 years) with two, 115 with three and 96 with four repeated 25-OH-D3 measurements were identified. Mean adjusted 25-OH-D3 (48.2 nmol/l) and PTH (34.9 ng/l) levels remained stable over 120 weeks. 5% of the patients had an elevated PTH > 65 ng/l. High total cholesterol ≥ 200 mg/dl and high triglycerides ≥ 130 mg/dl were associated with higher 25-OH-D3 levels.

CONCLUSION

We propose a simple method to include sunshine duration in the analysis of 25-OH-D3 levels to minimise the bias of seasonal variation. Based on our data we established the pragmatic strategy of limiting vitamin D supplementation to patients with biochemical signs of mineralisation disorders such as elevated PTH and alkaline phosphatase (AP). In children with normal PTH and AP we recommend adjustment of calcium intake and increase of outdoor activity instead.

Effects of vitamin D supplementation on metabolic parameters, serum irisin and obesity values in women with subclinical hypothyroidism: a double-blind randomized controlled trial

Purpose

Subclinical hypothyroidism is an early, mild form of hypothyroidism that may progress to overt hypothyroidism if untreated. The current study aimed to assess the effects of vitamin D supplementation on hormonal (thyroid stimulating hormone [TSH], triiodothyronine, thyroxine, and free thyroxine) parameters, lipid profiles, serum irisin, and obesity indices in women with subclinical hypothyroidism.

Methods

The present randomized, double-blind, placebo-controlled clinical trial was carried out on 44 women with subclinical hypothyroidism. The participants were allocated to two groups (22 patients in each group) that received vitamin D (50,000 IU/week) or placebo for 12 weeks. Fasting blood samples, anthropometric and body composition measurements, physical activity levels, and dietary intakes were collected at baseline and at the end of the study.

Results

Vitamin D supplementation significantly decreased TSH, total cholesterol, and fat mass percentage, and significantly increased serum vitamin D and irisin levels and fat-free mass percentage compared to the control group (all, p<0.05). Changes in thyroid hormones, other lipid profiles, and anthropometric indices were not significantly different between the groups.

Conclusion

Our study indicates that vitamin D administration improves serum TSH, total cholesterol, irisin, and body composition in women with subclinical hypothyroidism. More well-designed clinical trials are required to confirm these findings and clarify the effects of vitamin D supplementation on both genders of patients.Clinical trial registration: https://www.irct.ir/trial/57482, Identifier IRCT20100408003664N25.

Targeted dietary approaches for the management of obesity and severe obesity in children and adolescents: A systematic review and meta-analysis

There is a need for a detailed understanding of effective dietary interventions for children with obesity. This systematic review examined the effectiveness of diets of varying energy content as a component of weight treatment in children and adolescents with obesity, severe obesity and obesity-related comorbidity. A systematic search of six databases, from 2000 to 2021, for intervention studies of targeted dietary treatment for obesity in children aged 2-18 years identified 125 studies. Dietary interventions were grouped according to diet type and energy target. Risk of bias was assessed using the Effective Public Healthcare Panacea Project assessment tool. Meta-analysis examined change in body mass index (BMI) at intervention end. A broad array of diet types were effective at reducing BMI in children with obesity. When dietary types were considered by energy target, a gradient effect was observed. Very-low energy diets were most effective with a - 4.40 kg/m² (n = 3; 95% CI -7.01 to -1.79). While dietary interventions with no specified energy target were ineffective, resulting in a BMI gain of +0.17 kg/m² (n = 22; 95% CI 0.05 to 0.40). Practical definitions of dietary energy target in the management of obesity and severe obesity are urgently required to ensure treatment seeking children have timely access to efficacious interventions.

Vitamin D and Zinc are Interlinked but Affected by Different Growth Factors in Iranian Children and Adolescents: Vitamin D and Zinc in Iranian Children and Adolescents

Background: Zinc and vitamin D are essential factors required for growth. Recently, studies have shown a possible link between serum zinc and vitamin D levels. Objectives: This study was designed to evaluate this link and its possible affecting growth factors in children and adolescents in Iran. Methods: This cross-sectional study was performed on the data obtained from children aged 2 to 18 years old referring to a growth assessment clinic for routine growth follow-ups in the city of Shiraz from April to August 2019. A total of 454 children who were checked for 25-hydroxyvitamin D and zinc simultaneously were included. Results: Vitamin D was negatively correlated with body mass index (BMI) z-scores, while zinc was positively correlated with vitamin D and height z-scores. Subjects with vitamin D levels ≤ 8.6 ng/mL were 2.081 times more likely to have a zinc deficiency. Vitamin D insufficiency was significantly higher in overweight and obese children. Mean vitamin D and zinc levels were significantly lower, and vitamin D insufficiency was significantly higher in boys than girls. While mean zinc levels were significantly lower in short children, the prevalence of zinc deficiency was not statistically different between short and normal height statures. Conclusions: Very low vitamin D levels are likely to be accompanied by zinc deficiency, possibly caused by malnutrition and the modulatory effect of serum vitamin D on zinc absorption. Unlike zinc deficiency, vitamin D insufficiency is much more prevalent in Iranian children than in children from other countries. Vitamin D and zinc are associated with BMI and height z-scores, respectively.

[Levels of fat-soluble vitamins A, D, and E and their influencing factors in children with obesity]

OBJECTIVES

To investigate the levels of fat-soluble vitamins A, D, and E in children with obesity and their influencing factors.

METHODS

A total of 273 children with obesity who attended the Department of Clinical Nutrition, Xi'an Children's Hospital, from January 2019 to April 2021 were enrolled as the obesity group. A total of 226 children with normal body weight who underwent physical examination during the same period were enrolled as the control group. Anthropometric parameters and body composition were measured for both groups, and the serum concentrations of vitamins A, D, and E were also measured.

RESULTS

Compared with the control group, the obesity group had significantly higher serum levels of vitamin A [(1.32±0.21) μmol/L vs (1.16±0.21) μmol/L, P<0.001] and vitamin E [(9.3±1.4) mg/L vs (8.3±1.2) mg/L, P<0.001] and a significant reduction in the level of 25-hydroxyvitamin D [(49±22) nmol/L vs (62±24) nmol/L, P<0.001]. In the obesity group, the prevalence rates of marginal vitamin A deficiency, vitamin D deficiency/insufficiency, and vitamin E insufficiency were 5.5% (15/273), 56.8% (155/273), and 4.0% (11/273), respectively. After adjustment for body mass index Z-score and waist-to-height ratio, serum vitamin A level was positively correlated with age (P<0.001), while vitamins E and 25-hydroxyvitamin D levels were negatively correlated with age in children with obesity (P<0.001). After adjustment for age, the serum levels of vitamin A, vitamin E and 25-hydroxyvitamin D were not correlated with degree of obesity, percentage of body fat, and duration of obesity in children with obesity, while the serum levels of vitamins A and E were positively correlated with waist-to-height ratio (P<0.001).

CONCLUSIONS

There are higher serum levels of vitamins A and E in children with obesity, especially in those with abdominal obesity, while serum vitamin D nutritional status is poor and worsens with age. Therefore, vitamin D nutritional status should be taken seriously for children with obesity, and vitamin D supplementation should be performed when necessary.

Environmental Factors That Affect Parathyroid Hormone and Calcitonin Levels

Calciotropic hormones, parathyroid hormone (PTH) and calcitonin are involved in the regulation of bone mineral metabolism and maintenance of calcium and phosphate homeostasis in the body. Therefore, an understanding of environmental and genetic factors influencing PTH and calcitonin levels is crucial. Genetic factors are estimated to account for 60% of variations in PTH levels, while the genetic background of interindividual calcitonin variations has not yet been studied. In this review, we analyzed the literature discussing the influence of environmental factors (lifestyle factors and pollutants) on PTH and calcitonin levels. Among lifestyle factors, smoking, body mass index (BMI), diet, alcohol, and exercise were analyzed; among pollutants, heavy metals and chemicals were analyzed. Lifestyle factors that showed the clearest association with PTH levels were smoking, BMI, exercise, and micronutrients taken from the diet (vitamin D and calcium). Smoking, vitamin D, and calcium intake led to a decrease in PTH levels, while higher BMI and exercise led to an increase in PTH levels. In terms of pollutants, exposure to cadmium led to a decrease in PTH levels, while exposure to lead increased PTH levels. Several studies have investigated the effect of chemicals on PTH levels in humans. Compared to PTH studies, a smaller number of studies analyzed the influence of environmental factors on calcitonin levels, which gives great variability in results. Only a few studies have analyzed the influence of pollutants on calcitonin levels in humans. The lifestyle factor with the clearest relationship with calcitonin was smoking (smokers had increased calcitonin levels). Given the importance of PTH and calcitonin in maintaining calcium and phosphate homeostasis and bone mineral metabolism, additional studies on the influence of environmental factors that could affect PTH and calcitonin levels are crucial.

Vitamin D Level Trajectories of Adolescent Patients with Anorexia Nervosa at Inpatient Admission, during Treatment, and at One Year Follow Up: Association with Depressive Symptoms

(1) Background: Evidence has accumulated that patients with anorexia nervosa (AN) are at higher risk for vitamin D deficiency than healthy controls. In epidemiologic studies, low 25(OH) vitamin D (25(OH)D) levels were associated with depression. This study analyzed the relationship between 25(OH)D serum levels in adolescent patients and AN and depressive symptoms over the course of treatment. (2) Methods: 25(OH)D levels and depressive symptoms were analyzed in 93 adolescent (in-)patients with AN from the Anorexia Nervosa Day patient versus Inpatient (ANDI) multicenter trial at clinic admission, discharge, and 1 year follow up. Mixed regression models were used to analyze the relationship between 25(OH)D levels and depressive symptoms assessed by the Beck Depression Inventory (BDI-II). (3) Results: Although mean 25(OH)D levels constantly remained in recommended ranges (≥50 nmol/L) during AN treatment, levels decreased from (in)patient admission to 1 year follow up. Levels of 25(OH)D were neither cross-sectionally, prospectively, nor longitudinally associated with the BDI-II score. (4) Conclusions: This study did not confirm that 25(OH)D levels are associated with depressive symptoms in patients with AN. However, increasing risks of vitamin D deficiency over the course of AN treatment indicate that clinicians should monitor 25(OH)D levels.

Are there any seasonal variations in 25-hydroxyvitamin D and parathyroid hormone serum levels in children and adolescents with severe obesity?

The objective of this study was to analyze the prevalence of hypovitaminosis D in children with severe obesity. We hypothesized that severe obesity could modify the seasonal variations in 25(OH)D and PTH serum levels throughout the year. A cross-sectional clinical and blood testing (calcium, phosphorus, 25(OH)D, and PTH) was carried out in 282 patients with severe obesity, aged 7.2-15.2 years. A control group was recruited (348 healthy children, aged 7.1-14.9 years). The criteria of the US Endocrine Society were used for the definition of hypovitaminosis D. Vitamin D deficiency and hyperparathyroidism were more frequent (p < 0.05) in the obesity group (44.5 vs. 11.5% and 22.4 vs. 3.9%, respectively). There were seasonal variations in 25(OH)D levels in the obesity group, but they were lower (p < 0.05) with respect to the control group. In contrast, PTH levels were higher (p < 0.05) in the obesity group with respect to the control group, but there were no significant seasonal variations in PTH levels.Conclusion: Suboptimal vitamin D status and high levels of PTH are a common feature in pediatric population with severe obesity. In these patients, the seasonal variations in 25(OH)D were not modified, and PTH levels remained increased throughout the year, but without any seasonal variations. What is Known: • Obesity has been associated with lower 25(OH)D and higher PTH levels. • Relation among vitamin D and PTH through a natural year in children with obesity is partially known. What is New: • Seasonal variations in 25(OH)D are maintained in children with severe obesity, but PTH levels remained increased throughout the year, without seasonal variations. • -PTH levels in obesity are independent of vitamin D status and do not appear to represent secondary hyperparathyroidism.

Body mass index is associated with hyperparathyroidism in pediatric kidney transplant recipients

BACKGROUND

Hyperparathyroidism persists in up to 50% of pediatric kidney transplant recipients. The aims of this study were to describe the evolution of parathyroid hormone (PTH) in the first year after transplantation and to identify factors associated with hyperparathyroidism.

METHODS

This retrospective study included children who underwent kidney transplantation at the University Hospitals of Ghent, Leuven, Rotterdam, or Amsterdam. Data from 149 patients were collected before and up to 12 months after transplantation. Severe hyperparathyroidism was defined as PTH 2-fold above the reference value. Factors associated with hyperparathyroidism and severe hyperparathyroidism were identified using multivariate logistic regression analysis.

RESULTS

Before transplantation, 97 out of 137 patients (71%) had hyperparathyroidism. The probability of hyperparathyroidism and severe hyperparathyroidism declined from 0.49 and 0.17 to 0.29 and 0.09 at 3 and 12 months after transplantation, respectively. BMI SDS (β: 0.509; p = 0.011; 95% CI: 1.122-2.468), eGFR (β: - 0.227; p = 0.030; 95% CI: 0.649-0.978), and pre-transplant hyperparathyroidism (β: 1.149; p = 0.039; 95% CI: 1.062-9.369) were associated with hyperparathyroidism 12 months after transplantation. Pre-transplant hyperparathyroidism (β: 2.115; p = 0.044; 95% CI: 1.055-65.084), defined as intact parathormone (iPTH) levels > 65 ng/l (6.9 pmol/l) or 1-84 PTH > 58 ng/l (6.2 pmol/l), was associated with severe hyperparathyroidism at 3 months. Only eGFR (β: - 0.488; p = 0.010; 95% CI: 0.425-0.888) was inversely associated with severe hyperparathyroidism at 9 months after transplantation.

CONCLUSIONS

Allograft function remains the main determinant of severe hyperparathyroidism after transplantation. Our findings emphasize the importance of BMI and pre-transplant PTH control.

Associations Between Different Dietary Vitamins and the Risk of Obesity in Children and Adolescents: A Machine Learning Approach

BACKGROUNDS

Simultaneous dietary intake of vitamins is considered as a common and real scenario in daily life. However, limited prospective studies have evaluated the association between multivitamins intake and obesity in children and adolescents.

OBJECTIVES

This study aimed to evaluate the relationship between the intake of different dietary vitamins and the risk of obesity in children (6-11 years) and adolescents (12-19 years).

METHODS

We conducted a cross-sectional study based on data from U.S. National Health and Nutrition Examination Survey, 2013-2016. A total of 3634 children and adolescents were included who had available data on dietary vitamins, obesity and covariates. We analyzed the dietary intake levels of nine vitamins, including vitamin A, vitamin B₁, vitamin B₂, vitamin B₆, vitamin B₁₂, vitamin C, vitamin D, vitamin E, vitamin K. Multivariate logistic regression was used to model the associations between vitamins and obesity. Bayesian kernel machine regression (BKMR) was employed to explore the joint and independent effects of vitamins on obesity among children and adolescents.

RESULTS

In the multivariate logistic regression model, five vitamins (vitamin A, vitamin B₁, vitamin B₂, vitamin B₁₂, and vitamin D) were negatively associated with obesity in children and adolescents. BKMR analysis showed that when the concentration of the nine vitamins was at or above the 55th percentile compared with the median value, the combined intake of these vitamins could significantly reduce the risk of obesity in children and adolescents. Potential interactions between vitamin B₂ and vitamin B₁₂ in increasing the risk of obesity in children and adolescents were observed.

CONCLUSIONS

We determine the combined effects of multivitamins on obesity in children and adolescents, and observe a significant interaction between vitamin B₂ and vitamin B₁₂. Further cohort studies are needed to clarify the health effects of multivitamins intake in a larger population.

The functional nutritional and regulatory activities of calcium supplementation from eggshell for obesity disorders management

The present study was to investigate the effective role of renewable sources of Ca⁺² from eggshell (ES) with different doses to restrict obesity disorders. Rats were classified as follows, G₁ : normal diet for 26 weeks; G₂ : high-fat diet (HFD) for 26 weeks; G₃ , G₄ , and G₅ were supplemented with HFD for 16 weeks and treated with 7.2 g Ca⁺² ES/Kg rat chow, 18 g Ca⁺² ES/Kg rat chow, and 2% diet containing fat (DCF), respectively, for the remaining 10 weeks. Results revealed a significant effect of the low dose of Ca⁺² supplement in form of ES than high dose and 2% DCF; on basis of anthropometric parameters, lipid, leptin, adiponectin, thyroid hormones, Ca⁺² , 25-hydroxyl vitamin-D, and oxidative and inflammatory parameters were regulated. Results were confirmed with the histopathological study. Therefore, it was concluded that Ca⁺² supplementation can be used as a beneficial source for obesity management with anticholesterol actions. PRACTICAL APPLICATIONS: Obesity represented public health hazards. The eggshell is one of the waste products that contain a high percentage of Ca⁺² . The current data exposed using a low dose of ES as a new source of Ca⁺² supplement for treatment of HFD rats leads to significant enhancement of lipid profiles, liver enzymes, kidney functions, leptin, adiponectin, Ca⁺² , 25(OH)-D, TSH, fT_4, and PTH levels. Also, there was a reduction in weight gain, Bwt, BMI, BG, insulin, and HOMA-IR. Moreover, the oxidant-pro-oxidant system was improved in both hepatic and adipose tissues where NO and TBARS concentrations were diminished, and SOD specific activity was elevated. Additionally, TNF-α and ADAM17 expression were downregulated. Hence, it was concluded that there was good evidence that diets supplemented with ES were associated with the reduction of obesity complications especially regulating fat processing and storage in the body.