Vitamin D binding protein (DBP) and albumin are the important determinants of circulatory 25(OH)D in adults. Physiological function of vitamin D is particularly regulated by DBPs. Serum parathyroid hormone (PTH) is considered as the biological activity reader of circulating 25(OH)D. We therefore examined the relationships between serum total, free, and bioavailable 25(OH)D versus PTH in apparen...

background: this study aims to assess the relationship of serum mg and vitamin d levels in a nationally-representative sample of iranian adolescents. methods: the study participants consisted of 330 students, aged range from 10 to 18 years, consisting of an equal number of individuals with and without hypovitaminosis d. the correlation between serum 25 hydroxy vitamin d (25(oh) d) and magnesium...

Total 25(OH)D levels were determined to assess bone health in elderly populations; however, the bioavailability of 25(OH)D is regulated by the albumin and vitamin D binding protein (DBP) levels and DBP variations. Whether bioavailable 25(OH)D level is a superior biomarker for vitamin D than total 25(OH)D level regarding the BMD and the bone metabolism were not yet fully understood. With a commu...

background: association between the vitamin d deficiency and metabolic syndrome (mets) has previously been noted and reported to be controversial. the aim of this study was to determine the association of serum 25 (oh) d level and vitamin d dietary intake with mets among iranian population . methods: this analytical study was conducted on 122 patients with mets based on the atpiii criteria and ...

Objective. This paper aims to assess 25(OH)D levels in Italian children and adolescents identifying risk factors for 25(OH)D deficiency and to evaluate whether a normal 25(OH)D value can be restored in 25(OH)D-deficient patients. Methods. We evaluated 25(OH)D levels in 679 Italian children and adolescents (≤10, 11-20, 21-30, and >30 ng/mL were defined as severe deficiency, deficiency, insuffici...

BACKGROUND Patients have been described with loss-of-function CYP24A1 (cytochrome P450, family 24, subfamily A, polypeptide 1) mutations that cause a high ratio of 25-hydroxyvitamin D to 24,25-dihydroxyvitamin D [25(OH)D/24,25(OH)2D], increased serum 1,25-dihydroxyvitamin D, and resulting hypercalcemia, hypercalciuria and nephrolithiasis. A 25(OH)D/24,25(OH)2D ratio that can identify patients w...

BACKGROUND Vitamin D sufficiency may be determined by the serum concentration of 25-hydroxyvitamin D [25(OH)D] that results in maximal intestinal calcium absorption efficiency. However, some investigators questioned whether 25(OH)D concentrations above the concentrations associated with rickets or osteomalacia influence calcium absorption. OBJECTIVE We determined whether calcium absorption ef...

Asian Indians who immigrate to northern Europe have lower serum 25-hydroxyvitamin D [25(OH)D] than Caucasians, and they develop vitamin D deficiency, rickets, and osteomalacia. We investigated vitamin D metabolism, the effects of 25(OH)D3 on vitamin D metabolism and activity of 25(OH) D-24-hydroxylase, the rate-limiting enzyme for degradation of 25(OH)D, from cultured skin fibroblasts of Asian ...