Nutritional vitamin D use in chronic kidney disease: a survey of pediatric nephrologists

Native vs. active vitamin D in children with chronic kidney disease: a cross-over study

BACKGROUND

The rationale for the prescription of vitamin D analogues in patients with chronic kidney disease (CKD) is still a matter of debate. We aimed to compare native vs. active forms of vitamin D on pre-dialysis children with CKD and evaluate effects on calcium (Ca), phosphorus (P), and parathyroid hormone (PTH).

METHODS

Thirty children with pre-dialysis CKD were enrolled in a prospective cross-over study. Patients were randomly classified into two groups. Group A received native cholecalciferol while group B received alfacalcidol for 3 months. After 1 month (washout period), patients were switched to receive the opposite form for another 3 months. Serum Ca, P, alkaline phosphatase (ALP), PTH, and 25(OH)D₃ were measured at study start (BL-1), end of first period (FU-1), before second period (BL-2), and after second period (FU-2).

RESULTS

There was significant increase in levels of 25(OH)D₃ after administration of either native or active vitamin D in the first period in both groups (p < 0.001 and < 0.001, respectively) and also in the second period for both groups (p = 0.02 and < 0.001, respectively). There was no significant difference between both groups regarding changes in serum Ca (1st period; p = 0.770 and 2nd period; p = 0.412), serum P (1st period; p = 0.835, 2nd period; p = 0.052), and serum PTH (1st period; p = 0.250, 2nd period; p = 0.539).

CONCLUSION

Alfacalcidol and native vitamin D3 were equally effective in decreasing PTH levels and increasing serum 25(OH)D₃ in pre-dialysis CKD patients. There was no significant difference between the two forms regarding changes in serum Ca or P. Graphical abstract.

[Vitamin D deficiency in childhood: an opportunity for prevention]

The prevalence of vitamin D deficiency in the pediatric population has increased in recent years and continues to be underdiagnosed and undertreated. According to data from the "ENSANUT 2006" (National Health and Nutrition Survey), the prevalence of vitamin D deficiency in Mexico was 16% in children aged 2-12 years. Vitamin D plays a critical role in the formation and bone homeostasis and consequently on growth. Its deficiency is clearly associated with diseases such as rickets and osteomalacia, and it has been linked to other diseases such as obesity, metabolic syndrome, diabetes, cancer, respiratory infections and immune system disease. Specific risk groups have been described in the medical literature for vitamin D deficiency in which supplementation may offer a benefit. Currently, there is still controversy in defining the serum levels of proficiency and dose supplementation. In Mexico, the daily suggested intake of vitamin D is 5.6μg (224 IU), which is significantly lower than the recommendations in the U.S. and Europe (i.e., between 400 and 1000 IU/day). An increase in vitamin D deficiency has been reported in recent years. There is no consensus regarding the sufficiency levels of vitamin D. Cut-off values vary from 20 to 30ng/ml. Therefore, the objective of this review was to provide an overview of the problem in the pediatric population and to describe the groups at risk, as well as to analyze the current recommendations for vitamin D supplementation. Vitamin D deficiency was considered rare in Mexico according to the National Institute of Medical Science and Nutrition Salvador Zubirán. Lack of evidence did not help to establish the international recommended daily intake. Currently, vitamin D deficiency must be recognized as a health problem, worthy of attention and action. We suggest that prospective studies are carried out in our country where the relationship between serum vitamin D deficiency and poor bone mineralization will be established.