Vitamin D Status in Urinary Calcium Stone Formation

Netelenbos, J. C.

doi:10.1001/archinte.1985.00360040105023

Cited by 37 publications

(16 citation statements)

References 20 publications

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“…The strong positive correlation between plasma concentrations of (24<R)-hydroxycalcidiol and calcidiol is consistent with earlier studies of our group (33,35). In patients with primary hyperparathyroidism, the regression line was displaced to the right, implicating a threshold concentration of about 15 nmol/1 above which (24jR)-hydroxycalcidiol is produced from calcidiol.…”

Section: Discussionsupporting

confidence: 91%

“…In patients with primary hyperparathyroidism, the regression line was displaced to the right, implicating a threshold concentration of about 15 nmol/1 above which (24jR)-hydroxycalcidiol is produced from calcidiol. In healthy subjects this concentration may be close to 0 (33,35). The threshold concentration explained the significantly lower PR/[calcidiol] ratios (tab.…”

Section: Discussionmentioning

confidence: 88%

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Human Pharmacokinetics of Orally Administered (24 R)-Hydroxycalcidiol

Leeuwenkamp

Wiel²,

Lips³

et al. 1993

Clinical Chemistry and Laboratory Medicine

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Summary:To gain an insight in the regulation of (24jR)-hydroxycalcidiol, we studied the pharmacokinetics of orally administered (24R)-hydroxycalcidiol in 6 healthy subjects without calcium supplementation, in 4 healthy subjects with calcium supplementation and in 6 patients with primary hyperparathyroidism. Various quantities related to calcium and vitamin D metabolism were also monitored.In the healthy subjects without calcium supplementation, the basal (24/?)-hydroxycalcidiol concentration (C b ) in serum was 2.4 ± 0.8 nmol/1 (mean ± SD, n = 5), the terminal serum half-time (t I/2 ) 7.2 ±1.4 days, the production rate 0.05 ± 0.01 nmol/kg · day, and the production rate/[calcidiol] ratio (1.5 ± 0.4 χ 10~3 I/kg • day). In the healthy subjects studied, the serum concentration vs time curves exhibited a second maximum after administration, possibly due to binding by intestinal cells or (partial) uptake by the lymph system. In the calcium-supplemented healthy subjects, the pharmacokinetic quantities were not significantly different while the area under the serum concentration-time curve and the estimated bioavailability were significantly decreased.Basal concentration (C b ), production rate and the production rate/[calcidiol] ratio were significantly lower in patients with primary hyperparathyroidism but ti/ 2 was unchanged.Exogenous (24jR)-hydroxycalcidiol had no clear effect on calcium and vitamin D metabolism.In conclusion, a) exogenous (24JR)-hydroxycalcidiol has no clear effect on calcium and vitamin D metabolism, b) clearance and production rate of (24/?)-hydroxycalcidiol are not affected by calcium supplementation, c) bioavailability is lower in the calcium-supplemented state, d) basal concentration (C b ) and production rate are significantly decreased in patients with hyperparathyroidism.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 88%

Human Pharmacokinetics of Orally Administered (24 R)-Hydroxycalcidiol

Leeuwenkamp

Wiel²,

Lips³

et al. 1993

Clinical Chemistry and Laboratory Medicine

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“…In the present study, we assessed the vitamin D status in patients with nephrolithiasis and found that 35 and 19% had vitamin D insufficiency and deficiency, respectively. Netelenbos et al [1], having measured vitamin D metabolites in 160 calcium stone formers, commented that the prevalence of 25(OH)D insufficiency was similar to that in healthy control subjects (55 ± 23 vs. 53 ± 22).…”

Section: Discussionmentioning

confidence: 99%

“…Netelenbos et al [1] have concluded that there was no major pathophysiologic role of the main vitamin D (vitamin D) metabolites in urinary calcium stone formation, while Dimkovic et al [2] considered low level serum 25(OH)D as an additional risk factor for stone formation in patients with normocalcemic hyperparathyroidism.…”

Section: Introductionmentioning

confidence: 99%

Vitamin D Status in Patients with Recurrent Kidney Stones

Pipili

Oreopoulos²

2013

Nephron Clin Pract

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Data regarding the prevalence of 25-hydroxyvitamin D (25(OH)D) insufficiency in patients with nephrolithiasis, and the effects of vitamin D supplementation on parathyroid hormone (PTH) are few and conflicting. In this article, we examined the prevalence of vitamin D insufficiency and deficiency in 236 recurrent kidney stone formers and the correlation of vitamin D levels with other parameters of stone formation. The prevalent stone composition was calcium oxalate (80.4%) and uric acid (16.45%). One third of stone formers had vitamin D insufficiency and a quarter of them high PTH levels (PTH >7.5 pmol/l) with normal serum (total and ionized) calcium values. Predictor of high PTH was low 25(OH)D level (r = 0.989, r² = 0.977, p < 0.001). Stone formers with hypercalciuria had higher 25(OH)D values (72.26 ± 4.21 vs. 59.29 ± 1.76, p = 0.0013) compared to stone formers with urine calcium within normal ranges. Further studies are needed in order to better define the consequences of vitamin D insufficiency and to evaluate the impact of the therapeutic interventions in this cohort.

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“…Actually, epidemiological studies did not evidence a link between 25(OH)D serum levels and kidney stone formation or urinary calcium excretion (9)(10)(11). One study found no difference in 25(OH)D serum levels between stone formers and control individuals but identified higher 25(OH)D serum levels in hypercalciuric stone formers than in normocalciuric stone formers (12). Another study identified a correlation between 25(OH)D serum levels and urinary calcium excretion in kidney stone formers (13).…”

Section: -Hydroxyvitamin D [(25(oh)d] Depends On Nutritional Intakementioning

confidence: 99%