Vitamin D status and its relation to insulin resistance in a Mexican pediatric population

Association of adiposity, serum vitamin D, and dietary quality with cardiometabolic risk factors in children aged 6-12 years: findings from SEANUTS II Malaysia

Increased cardiometabolic risk among children is increasingly becoming a concern, with evidence indicating that obesity, diet, and serum 25-hydroxyvitamin D (25(OH)D) are associated with cardiometabolic risk. However, such studies among Malaysian children are scarce. Thus, this study explores the associations between adiposity, dietary quality, and 25(OH)D, with cardiometabolic risk factors among Malaysian children aged 4-12 years. Data of 479 children (mean age: 8.2 ± 2.3 years old, 52% females) from the South East Asian Nutrition Surveys (SEANUTS II) Malaysia, were included in this analysis. Adiposity (percentage of body fat) was assessed with bioelectrical impedance technique. Dietary quality was assessed using 24 h dietary recall and calculated as mean adequacy ratio. Vitamin D was assessed based on serum 25-hydroxyvitamin D (25(OH)D). Measurements of cardiometabolic risk factors included waist circumference (WC), mean arterial pressure (MAP), fasting blood glucose (FBG), high-density lipoprotein (HDL), triglyceride, and high-sensitivity C-reactive protein, and cardiometabolic risk cluster score (siMS) was calculated. Overall, higher adiposity was positively associated with all cardiometabolic risk factors (WC, ß = 0.907; 95% CI = 0.865, 0.948; MAP, ß = 0.225; 95% CI = 0.158, 0.292; HDL, ß = -0.011; 95% CI = -0.014, -0.009; Triglyceride, ß = 0.012; 95% CI = 0.009, 0.016; FBG, ß = 0.006; 95% CI = 0.002, 0.011) and siMS score (ß = 0.033; 95% CI = 0.029, 0.037). Serum 25(OH)D was inversely associated with siMS score (ß = -0.002; 95% CI = -0.004, -0.000008) and positively associated with HDL (ß = 0.002; 95% CI = 0.0001, 0.003). Our findings suggest that adiposity is a key determinant of adverse cardiometabolic risk factors in children, while serum 25(OH)D may be associated with overall cardiometabolic health. Interventions to reduce obesity are needed to mitigate the deleterious consequences of cardiometabolic dysregulation in children.

Association between serum 25-hydroxyvitamin-D and Triglycerides-Glucose index among Indian adolescents

Background

Vitamin D deficiency has been found to associated with numerous skeletal and non-skeletal diseases including Diabetes Mellitus. Insulin Resistance (IR) is considered as one of the primary reasons of Type-2 Diabetes Mellitus (T2DM). The association between vitamin D deficiency and IR has been extensively explore in previous studies, but none of them focused on Indian adolescents, and none of them used the TyG index as IR marker. Hence, this population-based cross-sectional study investigates the relationship between insulin resistance (IR) assessed using the Triglycerides Glucose Index (TyG index) and vitamin D measured by serum 25-hydroxyvitamin-D (25(OH)D).

Methods

For this study, we utilized data from the Comprehensive National Nutrition Survey (CNNS, 2016–18). The study is based on a sample size of 10,167 adolescents aged 10–19 years. The TyG index cut-off value of 4.65 was used to classify IR. We examined associations between the TyG index and serum 25(OH)D using multiple linear regression models adjusted for potential confounders. Odds of Insulin Resistance among vitamin D deficient/insufficient adolescents were assessed using multivariable logistic regression.

Results

A significant negative association was found between serum 25(OH)D and the TyG index, where a 10% increase in serum 25(OH)D was associated with 0.56 (95% CI = -0.67, -0.45) unit decrement in the TyG index. The odds of having IR were 90% higher among vitamin D deficient adolescents (OR: 1.90; 95% CI = 1.62—2.23) compared to adolescents with adequate levels of vitamin D. The association between vitamin D deficiency and IR was independent of sex; in other words, the association between vitamin D and IR was significant in both the sexes.

Conclusion

Independent of sex, this study found a significant inverse association between vitamin D and insulin resistance in Indian adolescents. The findings of this study highlight the utility of TyG index and the importance of vitamin D in lowering the risk of T2DM in future generations of the country.

Breastfeeding and vitamin D

The recent re-emergence of vitamin D deficiency (VDD) and rickets among breastfed infants without adequate sunlight exposure and vitamin D supplementation has been reported worldwide. Breastfed infants are particularly vulnerable to VDD because of the low vitamin D content of breast milk, restricted sunlight exposure, increased pollution, and limited natural dietary sources of vitamin D. The prevalence of VDD in breastfed infants differs vastly between studies and nations at 0.6%-91.1%. The recommended intake of vitamin D for lactating mothers to optimize their overall vitamin D status and, consequently, of their breast milk is 200-2,000 IU/day, indicating a lack of consensus. Some studies have suggested that maternal high-dose vitamin D supplementation (up to 6,400 IU/day) can be used as an alternate strategy to direct infant supplementation. However, concern persists about the safety of maternal high-dose vitamin D supplementation. Direct infant supplementation is the currently available option to support vitamin D status in breastfed infants. The recommended dose for vitamin D supplementation in breastfed infants according to various societies and organizations worldwide is 200-1,200 IU/day. Most international guidelines recommend that exclusively or partially breastfed infants be supplemented with 400 IU/day of vitamin D during their first year of life. However, domestic studies on the status and guidelines for vitamin D in breastfed infants are insufficient. This review summarizes the prevalence of VDD in breastfed infants, vitamin D content of breast milk, and current guidelines for vitamin D supplementation of lactating mothers and infants to prevent VDD in breastfed infants.

Serum 25-Hydroxyvitamin D correlates with systolic blood pressure in obese male schoolchildren

INTRODUCTION

Childhood obesity is associated with an increased risk of chronic diseases. We aimed to examine the relation between serum levels of 25-hydroxyvitamin D (25[OH]D) and blood pressure in obese schoolchildren.

MATERIAL AND METHODS

Cross-sectional study in school-age children with obesity. The serum levels of 25(OH)D were measured and classified as sufficient or insufficient/deficient. Blood pressure was measured. Normal values were considered <90th percentile, elevated blood pressure ≥90th to <95th percentiles, and hypertension ≥95th percentile, according to blood pressure reference tables, specific for age, sex, and height. The Pearson correlation was performed.

RESULTS

256 obese schoolchildren (123 [48.0%] females and 133 [51.9 %] males) were evaluated. The prevalence rates of vitamin D deficiency, insufficiency, and sufficiency were 23.4%, 52.3%, and 24.2%, respectively. Normal blood pressure was observed in 101 (39.4%) children; the frequencies of elevated blood pressure and hypertension were 10.9% and 49.6%, respectively. A moderate inverse correlation of 25(OH) D levels with systolic blood pressure levels (r = -0.54, p = 0.03) was observed. When analyzed by sex, a significantly high inverse correlation between 25(OH)D levels and systolic blood pressure was observed in males (r=-0.85 and p=<0.001). No significant correlation was found in females (systolic r=-0.16 and p=0.67; diastolic r= -0.15 and p=0.812). When performing the multiple regression analysis, the 25(OH)D levels and body mass index (BMI) were the significant predictors for systolic blood pressure.

CONCLUSIONS

We identified an inverse correlation between 25[OH]D levels and systolic blood pressure in male schoolchildren with obesity.