1. Atherosclerosis. 2009 Jun 6. [Epub ahead of print] Related Articles, Links
Serum vitamin D, parathyroid hormone levels, and carotid atherosclerosis
Reis JP, von Mühlen D, Michos ED, Miller ER 3rd, Appel LJ, Araneta MR, Barrett-Connor E
Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD, United States.
Evidence suggests low vitamin D and elevated parathyroid hormone (PTH) concentrations may increase risk for cardiovascular disease. However, little is known about the association between vitamin D or PTH and subclinical atherosclerosis. This cross-sectional study included 654 community-dwelling older adults aged 55-96 years (mean age, 75.5 years) without a history of coronary heart disease, revascularization, or stroke enrolled in the Rancho Bernardo Study who completed a clinic examination in 1997-1999 and provided a blood sample for determination of serum 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)(2)D], and PTH concentrations. Carotid artery intima-media wall thickness (IMT) was measured as an indicator of atherosclerosis at two sites with B-mode ultrasound. After adjusting for age, sex, smoking, alcohol intake, waist-to-hip ratio, exercise, season of blood draw, diabetes, and hypertension, geometric mean internal carotid IMT (p(trend) 0.022), but not common carotid IMT (p(trend) 0.834) decreased in a dose-dependent fashion with increasing concentration of 25(OH)D. There was no association of 1,25(OH)(2)D or PTH with either measure of carotid IMT. In subgroup analyses, 1,25(OH)(2)D was inversely associated with internal carotid IMT among those with hypertension (p for interaction 0.036). These findings from a population-based cohort of older adults suggest a potential role for vitamin D in the development of subclinical atherosclerosis. Additional research is needed to determine whether vitamin D may influence the progression of atherosclerosis, including the effects of supplementation on the atherosclerotic process.
2. Nephrol Dial Transplant. 2009 Jun 16. [Epub ahead of print] Related Articles, Links
Intracellular calcium homeostasis in patients with early stages of chronic kidney disease: effects of vitamin D3 supplementation
Lajdova I, Spustova V, Oksa A, Chorvatova A, Chorvat D Jr, Dzurik R
1Department of Clinical and Experimental Pharmacotherapy, Slovak Medical University, Bratislava, Slovak Republic.
BACKGROUND: Chronic renal failure has been referred to as a state of cellular calcium toxicity. The aim of this study was to investigate the status of free cytosolic calcium ([Ca(2+)](i)), intracellular calcium reserves and the capacitative calcium entry in peripheral blood mononuclear cells (PBMCs) of early-stage chronic kidney disease (CKD) patients, and to determine the effect of vitamin D(3) supplementation on these parameters. METHODS: The study involved 44 patients with CKD stages 2-3; 27 of them were treated with cholecalciferol (5000 IU/week) for 12 months. [Ca(2+)](i) was measured using Fluo-3 AM fluorimetry. Intracellular calcium reserves were emptied by the application of thapsigargin (Tg), a specific inhibitor of endoplasmic reticulum Ca(2+)-ATPase. 2-Aminoethyl-diphenyl borate (2APB) was used to examine the capacitative calcium entry. RESULTS: [Ca(2+)](i) of CKD patients was substantially higher in comparison with healthy subjects: 123 (115-127) versus 102 (98-103) nmol/l, P < 0.001. The calcium concentration of Tg-sensitive stores and the capacitative calcium entry were also significantly increased in CKD patients. After the 12-month vitamin D(3) supplementation, there was a marked decrease in [Ca(2+)](i) [105 (103-112) nmol/l, P < 0.001 versus baseline], independently of the increase in 25(OH)D(3) or the decrease in PTH levels. No significant changes in intracellular calcium reserves and the capacitative calcium entry were found. CONCLUSIONS: Our results demonstrate that (1) [Ca(2+)](i), intracellular calcium stores and the capacitative calcium entry were significantly increased already in early stages of CKD; (2) long-term vitamin D(3) supplementation normalized [Ca(2+)](i) without any effect on intracellular calcium reserves or the capacitative calcium entry.
3. J Trop Pediatr. 2009 Jun 8. [Epub ahead of print] Related Articles, Links
Clinical Responses to a Mega-dose of Vitamin D3 in Infants and Toddlers With Vitamin D Deficiency Rickets
Soliman AT, El-Dabbagh M, Adel A, Ali MA, Aziz Bedair EM, Elalaily RK
Division of Pediatric Endocrinology, Hamad Medical Centre, Doha, Qatar.
Objectives: Was to investigate the effect of treatment with an IM injection, a mega dose of vitamin D3 (10 000 IU/kg) on the clinical, biochemical and radiological parameters of 40 rachitic children with vitamin D deficiency (VDD) over a period of 3 months. Design: In this prospective study we evaluated the clinical, biochemical and radiological responses of an IM injection of cholecalciferol (10 000 IU/kg) for 3 months. Results: At presentation, the most frequent manifestations were enlarged wrist joints, hypotonia, irritability, cranial bossing, wide anterior fontanel, bow legs, delayed teething and walking and Harrison's sulcus with chest rosaries. Short stature (length SDS < -2) was recorded in 30% of patients. Craniotabes and hypocalcemic tetany were the least common presentations. In VDD children the most frequent biochemical abnormality was high alkaline phosphatase (ALP) (100%), followed by low phosphate (PO(4)) (75%) and low calcium (Ca) (12.5%). One month after treatment, serum Ca, PO(4) and 25(OH)D concentrations were normal. Three months after the injection, serum level of ALP and parathormone (PTH) decreased to normal. The majority of patients (87.5%) had serum 25(OH)D level >/= 20 ng/ml, but some (12.5%) had level <20 ng/ml. Hypercalcemia was not recorded in any patient during the 3-month-period. Significant cure of all symptoms and signs related to vitamin D deficiency had been achieved in all children. Leg bowing showed significant improvement in all patients but was still evident in one third. Complete healing of the radiological evidence of rickets was achieved in 95% of all children. Conclusion: An IM injection of a mega dose of cholecalciferol is a safe and effective therapy for treatment of VDD rickets in infants and toddlers with normalization of all the biochemical parameters and healing of radiological manifestations. Measurement of serum 25(OH)D level is highly recommended in all short children with a clear need for a general vitamin D supplementation for all infants and young children in Qatar.
PMID: 19506025 [PubMed - as supplied by publisher]
4. Osteoporos Int. 2009 Mar 12. [Epub ahead of print] Related Articles, Links
Determinants of 25-hydroxyvitamin D levels in African-American and Caucasian male veterans
Benjamin A, Moriakova A, Akhter N, Rao D, Xie H, Kukreja S, Barengolts E
Section of Endocrinology and Metabolism, Department of Medicine, University of Illinois Medical Center, MC 640, 1819 West Polk Street, Chicago, IL, 60612, USA.
Among 307 males seen in VA Medical Center, independent determinants (p < 0.01 for all) of serum 25-hydroxyvitamin D [25(OH)D] levels included race, vitamin D supplements, BMI, dietary calcium intake and smoking, but not age. Negative association between 25(OH)D and parathyroid hormone (PTH) was similar for Caucasian and African-American men. INTRODUCTION: In this prospective cohort study, we examined determinants of serum 25-hydroxyvitamin D [25(OH)D] levels and the relationship between 25(OH)D and PTH levels and body mass index (BMI). METHODS: Male veterans (n = 307) were recruited at a VA Medical Center. Serum levels of PTH and 25(OH)D were obtained. Surveys and chart reviews were completed. Vitamin D insufficiency was defined as 25(OH)D <30 ng/ml. Univariate and multivariate regression analyses were performed. RESULTS: Among 232 African-American (AA) men (mean +/- SD), 25(OH)D level (21.4 +/- 10.4 ng/ml) was lower and prevalence of insufficiency (80%) was higher than among 75 Caucasians (C; 28.5 +/- 11.1 ng/ml and 53%, respectively, p < 0.01 for both). In multivariate regression analysis, independent determinants (p < 0.01 for all) of 25(OH)D levels included AA race, vitamin D supplements, BMI, dietary calcium intake, and smoking. Despite lower 25(OH)D levels in African-Americans, PTH levels were similar to those seen in Caucasians. There was a significant (p < 0.02) negative linear association between 25(OH)D and PTH in African-American (r (2) = 0.05) and Caucasian (r (2) = 0.08) men, and there was no difference between the slopes of the relationship. CONCLUSIONS: 25(OH)D levels are determined by modifiable risk factors such as vitamin D supplementation in both AA and C males. The negative association between 25(OH)D and PTH is similar between the two races.
5. Cardiovasc Diabetol. 2009 Feb 3;8:7. Related Articles, Links
Parathyroid hormone, but not vitamin D, is associated with the metabolic syndrome in morbidly obese women and men: a cross-sectional study
Hjelmesaeth J, Hofsø D, Aasheim ET, Jenssen T, Moan J, Hager H, Røislien J, Bollerslev J
Morbid Obesity Center, Vestfold Hospital Trust, Health Region South, Tønsberg, Norway. email@example.com
BACKGROUND: The prevalence of vitamin D insufficiency and secondary hyperparathyroidism is high among morbidly obese subjects. Further, low serum levels of 25-hydroxyvitamin D (25 [OH]D) and magnesium have been associated with increased risk of the metabolic syndrome (MS), and recently, a possible link between PTH and MS has been reported. Although it is well known that the synthesis and secretion of PTH is regulated by serum levels of calcium, phosphate, magnesium and 25(OH)D, less is known about the possible clustered affiliation of these parameters with MS. We aimed to explore whether MS is associated with abnormal serum levels of PTH, 25(OH)D and magnesium in a population of morbidly obese patients. METHODS: Fasting serum levels of 25(OH)D, PTH and magnesium were assessed in a cross-sectional cohort study of 1,017 consecutive morbidly obese patients (68% women). Multiple logistic regression analyses were used to assess the independent effect of PTH, 25(OH)D and magnesium on the odds for MS (National Cholesterol Education Program [NCEP]) after adjustment for confounding factors. RESULTS: Sixty-eight percent of the patients had MS. Patients with MS had lower mean serum magnesium (P < 0.001) and higher mean PTH (P = 0.067) than patients without MS, whereas mean 25(OH)D did not differ significantly. Patients with PTH levels in the second to fourth quartiles had higher odds of prevalent MS (odds ratio 1.47 [95% CI 0.92-2.35], 2.33 [95% CI 1.40-3.87] and 2.09 [95% CI 1.23-3.56], respectively), after adjustment for 25(OH)D, magnesium, calcium, phosphate, creatinine, age, gender, season of serum sampling, BMI, current smoking, albuminuria, CRP, insulin resistance and type 2 diabetes. Further, PTH was significantly correlated with systolic and diastolic pressure (both P < 0.001), but not with the other components of MS. The levels of 25(OH)D and magnesium were not associated with MS in the multivariate model. CONCLUSION: The PTH level, but not the vitamin D level, is an independent predictor of MS in treatment seeking morbidly obese Caucasian women and men. Randomized controlled clinical trials, including different therapeutic strategies to lower PTH, e.g. calcium/vitamin D supplementation and weight reduction, are necessary to explore any cause-and-effect relationship.
（摘自Vitamin D Today）