Association of circulating 25-hydroxyvitamin D and parathyroid hormone with carotid intima media thickness in children and adolescents with excess weight

Vitamin D Deficiency and Carotid Media-Intima Thickness in Childhood Cancer Survivors

Childhood cancer survivors (CCS) are predisposed to developing numerous late effects of anticancer treatment later in life. The existing literature suggests that vitamin D deficiency (VDD) may influence cardiovascular abnormalities and metabolic diseases. The objectives of this study were to investigate the prevalence of VDD among childhood cancer survivors and examine the association of vitamin D deficiency and carotid intima-media thickness (IMT). The study comprised 111 childhood cancer survivors (62 males, 49 females) with a median follow-up time of 6.14 years. Vitamin D status was determined by measuring serum 25(OH)D levels using the automatic immunoenzymatic method. Ultrasonography of the common carotid artery (CCA), the carotid bulb, and the proximal part of the internal carotid artery (ICA) was conducted. Vitamin D deficiency (<20 ng/mL) was detected in 69.4% of CCS. A higher parathormone level and increased BMI were observed among VDD survivors. No effects of type of diagnosis, radiotherapy or hematopoietic stem cell transplantation on vitamin D status were observed. Our findings reveal that survivors with VDD exhibited significantly greater thickness in the CCA and carotid bulb. In conclusion, the results of our study of childhood cancer survivors demonstrate that vitamin D deficiency is prevalent in up to 70% of individuals. We did not confirm the hypothesis that factors related to anticancer treatment used during childhood contributed to the higher prevalence of VDD. Additionally, we did not verify the contribution of vitamin D deficiency to the increase in IMT thickness.

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

PURPOSE

To assess the efficacy of different doses of vitamin D₃ on serum 25-hydroxyvitamin D (25(OH)D), intact parathyroid hormone(iPTH), calcium, phosphorus, and alkaline phosphatase concentrations in overweight and obese school-children.

METHODS

A total of 378 children and adolescents, 6-13 years of age, with age- and sex-specific body mass index(BMI) Z-score ≥ 1(according to the World Health Organization criteria) were allocated to receive 600, 1000, and 2000 IU vitamin D₃/days. 25(OH)D, iPTH, calcium, phosphorus, and alkaline phosphatase concentrations were measured at baseline, 6, and 12 months. In this intention-to-treat analysis, we fitted a linear mixed effect model involving a random effect of participants within treatment groups and fixed effects of dose, time, and their interactions.

RESULTS

Mean(SD) of age and BMI Z-score were 9.3 (1.7) years and 2.55 (0.73), respectively. The median (IQR) for 25(OH)D was 11.5 (8.9), 11.7 (10.5), 12.2 (10.2) ng/mL (28.75, 29.25, and 30.50 nmol/L) at baseline and 23.1 (8.0), 25.6 (8.3), 28.6 (10.4) ng/mL (57.75, 64.00, and 71.50 nmol/L) at the end of 12 months in 600, 1000, and 2000 IU, respectively (p values for dose, time, and the interaction being < 0.0001, < 0.0001,and 0.082, respectively). Prevalence of vitamin D deficiency (< 20 ng/mL) was 80.2, 77.5, and 75.5% in 600, 1000, and 2000 IU groups at baseline, respectively, which decreased to 34, 18.4, and 7.5%, respectively, at 12 months. Patterns of iPTH, calcium, phosphorus, and alkaline phosphatase response over time did not differ significantly among groups (p values = 0.452, 0.670, 0.377, 0.895, respectively).

CONCLUSIONS

Increases in 25(OH)D concentration were found with supplementation of 1000 and 2000 IU, compared with 600 IU/days, whereas there was no evidence of iPTH suppression or change in serum calcium, phosphorus, and alkaline phosphatase among children with excess weight.

The Effect of Vitamin Supplementation on Subclinical Atherosclerosis in Patients without Manifest Cardiovascular Diseases: Never-ending Hope or Underestimated Effect?

Micronutrients, especially vitamins, play an important role in the evolution of cardiovascular diseases (CVD). It has been speculated that additional intake of vitamins may reduce the CVD burden by acting on the inflammatory and oxidative response starting from early stages of atherosclerosis, when the vascular impairment might still be reversible or, at least, slowed down. The current review assesses the role of major vitamins on subclinical atherosclerosis process and the potential clinical implications in patients without CVD. We have comprehensively examined the literature data for the major vitamins: A, B group, C, D, and E, respectively. Most data are based on vitamin E, D and C supplementation, while vitamins A and B have been scarcely examined for the subclinical atherosclerosis action. Though the fundamental premise was optimistic, the up-to-date trials with vitamin supplementation revealed divergent results on subclinical atherosclerosis improvement, both in healthy subjects and patients with CVD, while the long-term effect seems minimal. Thus, there are no conclusive data on the prevention and progression of atherosclerosis based on vitamin supplementation. However, given their enormous potential, future trials are certainly needed for a more tailored CVD prevention focusing on early stages as subclinical atherosclerosis.

The relation between circulating levels of vitamin D and parathyroid hormone in children and adolescents with overweight or obesity: Quest for a threshold

The level of serum 25-hydroxyvitamin D (25(OH)D) at which intact parathyroid hormone (iPTH) is maximally suppressed (suppression point) and below which PTH begins to rise (inflection point) has been used to define optimum 25(OH)D concentration. We aimed to study the association of circulating iPTH with 25(OH)D concentrations and to determine a 25(OH)D threshold associated with a significant iPTH suppression. This cross-sectional study was conducted on 198 boys and 180 girls, aged 6–13 years with BMI ≥ 1SD (WHO criteria) recruited from primary schools. Adjusted iPTH for BMI z-score, pubertal status, and dietary calcium was used. Nonlinear regression was used to model the relationship between 25(OH)D and iPTH and identify a suppression point for 25(OH)D at which iPTH reached a plateau. Piecewise regression analysis with a single knot for all possible values of 25(OH)D were fitted. Furthermore, 95% confidence intervals (95%CI) for those point had been calculated. The mean age (SD) of girls and boys was 9.1 (1.6) and 9.4 (1.7) years, respectively. Median 25(OH)D and iPTH were 13.8 ng/mL and 33.9 pg/mL in boys and 9.9 ng/mL and 47.8 ng/mL in girls, respectively. The equation in girls was: log-iPTH = 3.598+0.868 exp[(-0.190×25(OH)D. The point for near maximal suppression of iPTH by 25(OH)D for girls occurred at a 25(OH)D concentration of 20 ng/mL (95% CI: 7.1 to 32.2). No point of maximal suppression was found for boys. We also found a 25(OH)D threshold of 10 ng/mL (95% CI: 4.6 to 22.5) for girls (f: 9.8) by linear piecewise regression modeling of adjusted iPTH. No significant inflection point for boys was observed. In overweight/obese girls, when the concentration of 25(OH)D was higher than 20 ng/mL, an iPTH mean plateau level is reached, and when its concentrations approach 10 ng/mL, the slope of iPTH concentration has been accelerated.