Serum 25-hydroxyvitamin D is associated with obesity and metabolic parameters in US children

Does BMI Modify the Association between Vitamin D and Pulmonary Function in Children of the Mild Asthma Phenotype?

Vitamin D deficiency and obesity are global health problems that are associated with increased asthma risk in children. The purpose of this study was to investigate whether BMI modifies pulmonary function across vitamin D tertiles in pediatric asthma patients of the mild asthma phenotype. This cross-sectional study conducted from November 2016-September 2017 compared lung function variability as assessed by spirometry and nitric oxide in exhaled breath (FeNO) among 35 normal-weight and 26 overweight/obese Greek schoolchildren (5-12 years old) with mild asthma. Serum 25 (OH)D levels ≥ 30 ng/mL were defined as 'sufficient', 20-30 ng/mL 'insufficient', and <20 ng/mL 'deficient'. Stratification by BMI category, linear regression showed positive associations between D, % FVC (β = 0.49, 95%CI: 0.05, 0.94), and % FEV₁ (β = 0.48, 95%CI: -0.01, 0.95) in the normal-weight only, adjusted for age, sex, regular exercise, and medication. FEV₁ was 10% higher in the normal-weight D-sufficient group compared to those D-deficient (β = 10.43, 95%CI: 0.54, 20.32). No associations were observed for the overweight/obese group or FeNO. In conclusion, BMI modified associations of vitamin D on airway mechanics in children of the mild asthma phenotype. Serum 25 (OH)D concentrations ≥ 30 ng/mL were associated with higher ventilation in central airways of normal-weight asthmatic children.

The joint association of serum vitamin D status and cardiorespiratory fitness with obesity and metabolic syndrome in Tehranian adults

We aimed to assess the individual and joint association of serum vitamin D and cardiorespiratory fitness (CRF) with obesity and metabolic syndrome (MetSyn). In this cross-sectional study 270 adults with an age range of 18 years and older were recruited from health centers from five districts in Tehran, Iran. CRF was assessed with Bruce protocol. MetSyn was defined based on International Diabetes Federation 2009. The odds ratio (OR) and 95 % confidence interval (CI) of obesity and MetSyn across tertiles of serum vitamin D and CRF were estimated with control for confounders. The results indicated that neither 25(OH)D nor 1,25(OH)D was associated with obesity and MetSyn. There was a strong inverse association between CRF and general (P_-trend < 0.001) and abdominal adiposity (P_-trend: 0.001). The joint association of vitamin D and CRF indicated that the inverse association of CRF with obesity was stronger in those with high serum vitamin D than those with low serum vitamin D and this joint association remained after considering age and diet quality. There was a significant inverse association for those with low serum 25(OH)D and high CRF (OR: 0.12, 95 % CI: 0.04-0.81; P = 0.02) compared to those with low serum 25(OH)D and low CRF in the crude model. Also, the OR of general obesity was 0.17 (95 % CI: 0.02-0.79; P = 0.03) for those with high CRF and low serum 1,25(OH)D compare with the reference group. Our findings indicated a strong inverse association between CRF and obesity, especially in those with high serum vitamin D.

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.

Effects of Routine Health Care Combined with Oral Vitamin D on Linear Growth in 5-Year-Old Children

Objective

The aim is to evaluate the effects of routine health care combined with oral vitamin D on linear growth in 5-year-old children.

Materials and Methods

The 5-year-old children who received routine health care in Shiyan Maternal and Child Health Care Hospital from January 2019 to January 2021 were retrospectively analyzed. They were divided into the supplement group and the non-supplement group according to whether or not they received oral vitamin D, and reasons for not taking oral vitamin D and its influence on children's linear growth were analyzed.

Results

A total of 368 children were enrolled, including 228 children in the supplement group, accounting for 61.96%. The analysis of the influencing factors of vitamin D supplementation showed that the proportion of children with well-educated parents and living in cities and towns was higher (all P < 0.05). Comparing the general situation of children in the two groups, it was found that the height, weight, and head circumference of children in the supplement group were notably higher than those in the non-supplement group (all P < 0.05). At age 4 and 5, the height of the supplement group was significantly higher than that of the non-supplement group (all P < 0.001). Linear analysis showed that the relationship between height and age in the supplement group was Y (height, cm) = 10.07 × X (age, years) + 61.18, while that in the non-supplement group was Y (height, cm) = 8.296 × X (age, years) + 62.81, with significant difference (all P < 0.05). Serum 25-hydroxyvitamin D concentration in the supplement group was significantly higher than that in the non-supplement group, and the proportion of children ≥75 nmol/L was evidently higher than that in the supplement group (all P < 0.05). In addition, the incidence of vitamin D-related hypercalcemia in the supplement group was significantly higher than that in the non-supplement group (all P < 0.05).

Conclusion

There are still more children without vitamin D supplement, which is closely related to their parents' education background and place of residence. Additionally, vitamin D supplementation can promote growth and improve 25-hydroxyvitamin D levels in children, but with the risk of related complications.

Association of vitamin D status and cardio-metabolic risk factors in children and adolescents: the CASPIAN-V study

BACKGROUND

Metabolic syndrome (MetS) starts from early life and is one of the important underlying factors for non-communicable diseases (NCDs) in adulthood. Controversial evidence exists on the role of vitamin D deficiency in increasing the risk of pediatric MetS.

OBJECTIVE

This study aimed to assess the relationship between vitamin D level with MetS and its components in children and adolescents.

METHODS

This nationwide cross-sectional study was performed as part of a surveillance program in Iran. Participants were 2596 students, aged 7 to 18 years, living in 30 provinces. In addition to filling questionnaires, a physical examination was conducted, and blood samples were collected. The serum concentration of 25-hydroxy vitamin D (25(OH)D) was measured using the direct competitive immunoassay chemiluminescence method.

RESULTS

2596 students with a mean age of 12.2 y (55.1% boys) were recruited. Prevalence of vitamin D deficiency and insufficiency in participants was 10.6% (n = 276), and 60.5% (n = 1570), respectively. The prevalence of MetS was higher in the vitamin D deficient group. Students with deficient vitamin D levels had higher odds of MetS (OR: 4.25, 95%CI: 2.26-7.98), abdominal obesity (OR: 2.24, 95%CI: 1.61-3.12), low HDL-C (OR: 1.65, 95%CI: 1.18-2.30) and high fasting blood sugar (OR: 2.56, 95%CI: 1.43-4.57) in comparison to those with sufficient level of vitamin D.

CONCLUSION

Vitamin D deficiency was associated with increased odds of MetS and its components in the Iranian pediatric population. These findings underscore the importance of prevention and control of vitamin D deficiency in preventative programs against NCDs.

Adequate 25-hydroxyvitamin D levels are inversely associated with various cardiometabolic risk factors in Chinese children, especially obese children

OBJECTIVE

Vitamin D deficiency has recently evolved as a major public health issue worldwide. But the relationship between vitamin D and cardiovascular health in children remains unclear. Accordingly, we aimed to examine the associations between 25-hydroxyvitamin D (25(OH)D) concentrations and cardiometabolic risk factors, and to assess the possible effect modification of obesity on the associations in a Chinese pediatric population.

RESEARCH DESIGN AND METHODS

A cross-sectional sample of 6091 children aged 6-18 years was obtained using a cluster sampling method. The 25(OH)D concentrations, and metabolic risk factors, including waist to height ratio, blood pressure, blood lipids, fasting blood glucose (FBG), and insulin were measured. Adjusted ORs and multiplicative or additive interaction were calculated to assess the associations and effect modification, respectively.

RESULTS

Triglycerides, FBG, insulin, and homeostasis model assessment of insulin resistance were inversely associated with 25(OH)D concentrations (p<0.05) in both sexes. The OR of hyperglycemia among individuals with insufficient vitamin D was higher than those with adequate vitamin D after adjusting for covariates (OR: 1.47; 95% CI 1.26 to 1.70). Moreover, girls with insufficient vitamin D had significantly higher odds for hypertension and high total cholesterol than those with adequate vitamin D, which was not observed in boys. Thirty-two percent (95% CI 14% to 51%) of the increased odds of hyperglycemia can be explained by the interaction between insufficient vitamin D and obesity.

CONCLUSIONS

Vitamin D insufficiency is associated with increased odds of various cardiometabolic risk factors in Chinese children and has a synergistic effect on hyperglycemia with obesity.