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Adverse effects of low vitamin D status and calcium intakes in pregnancy may be mediated through functional effects on the calcium metabolic system. Little explored in pregnancy, we aimed to examine the relative importance of serum 25-hydroxyvitamin D (25(OH)D) and calcium intake on parathyroid hormone (PTH) concentrations in healthy white-skinned pregnant women. This cross-sectional analysis included 142 participants (14 ± 2 weeks' gestation) at baseline of a vitamin D intervention trial at 51.9 °N. Serum 25(OH)D, PTH, and albumin-corrected calcium were quantified biochemically. Total vitamin D and calcium intakes (diet and supplements) were estimated using a validated food frequency questionnaire. The mean ± SD vitamin D intake was 10.7 ± 5.2 μg/day. With a mean ± SD serum 25(OH)D of 54.9 ± 22.6 nmol/L, 44% of women were <50 nmol/L and 13% <30 nmol/L. Calcium intakes (mean ± SD) were 1182 ± 488 mg/day and 23% of participants consumed <800 mg/day. The mean ± SD serum albumin-adjusted calcium was 2.2 ± 0.1 mmol/L and geometric mean (95% CI) PTH was 9.2 (8.4, 10.2) pg/mL. PTH was inversely correlated with serum 25(OH)D ( r = -0.311, p < 0.001), but not with calcium intake or serum calcium ( r = -0.087 and 0.057, respectively, both p > 0.05). Analysis of variance showed that while serum 25(OH)D (dichotomised at 50 nmol/L) had a significant effect on PTH ( p = 0.025), calcium intake (<800, 800⁻1000, ≥1000 mg/day) had no effect ( p = 0.822). There was no 25(OH)D-calcium intake interaction effect on PTH ( p = 0.941). In this group of white-skinned women with largely sufficient calcium intakes, serum 25(OH)D was important for maintaining normal PTH concentration.

Guidelines for the prevention of glucocorticoid (GC) induced osteoporosis (GIOP) were implemented in a level 5 Irish Hospital with cross sectional audit of inpatient prescribing undertaken before and after. Prior to guideline implementation, elemental calcium (Ca) with Vitamin D (VitD) was prescribed for 11/66 (17%) of patients on GCs with 2/66 (3%) also receiving bisphosphonate (BP) therapy. Subsequent to guideline implementation, Ca with VitD was prescribed for 19/55 (35%) of patients on GCs with 11/55 (20%) also receiving BP therapy, representing a 2 and 6 fold respective increase. Internal promotion of guidelines is an effective strategy for healthcare improvement but needs refinement with or without repetition to achieve better patient outcomes.

Background: Interactions between calcium and vitamin D may have implications for the regulation of serum 25-hydroxyvitamin D [25(OH)D] and its catabolism and, consequently, the vitamin D dietary requirement., Objective: We investigated whether different calcium intakes influenced serum 25(OH)D and indexes of vitamin D activation and catabolism during winter and in the context of both adequate and inadequate vitamin D intakes., Design: A 15-wk winter-based, randomized, placebo-controlled, double-blind vitamin D₃ intervention (20 μg/d) study was carried out in free-living men and women aged ≥50 y (n = 125) who were stratified according to calcium intakes [moderate-low (<700 mg/d) or high (>1000 mg/d) intake]. The serum 25(OH)D concentration was the primary outcome, and serum calcium, parathyroid hormone (PTH), 1,25-dihydroxyvitamin D [1,25(OH)₂D], 24,25-dihydroxyvitamin D [24,25(OH)₂D], the ratio of 24,25(OH)₂D to 25(OH)D, vitamin D-binding protein, and free 25(OH)D were exploratory outcomes., Results: A repeated-measures ANOVA showed there was no significant (P = 0.2) time × vitamin D treatment × calcium intake grouping interaction effect on the mean serum 25(OH)D concentration over the 15-wk intervention period. Serum 25(OH)D concentrations increased (P ≤ 0.005) and decreased (P ≤ 0.002) in vitamin D₃ and placebo groups, respectively, and were of similar magnitudes in subjects with calcium intakes <700 mg/d (and even <550 mg/d) compared with >1000 mg/d. The response of serum PTH, 1,25(OH)₂D, 24,25(OH)₂D, the ratio of 24,25(OH)₂D to 25(OH)D, and free 25(OH)D significantly differed in vitamin D₃ and placebo groups but not by calcium intake grouping., Conclusions: We found no evidence of a vitamin D sparing effect of high calcium intake, which has been referred to by some authors as "vitamin D economy." Thus, recent dietary vitamin D requirement estimates will cover the vitamin D needs of even those individuals who have inadequate calcium intakes., (© 2014 American Society for Nutrition.)