Serum concentrations of 25-hydroxy vitamin D in Europeans and Asians after oral vitamin D3.

Serum concentrations of 25-hydroxy vitamin D (25-OHD3) were measured in seven Asians of Indian extraction and eight Europeans before and at intervals after taking 1 mg vitamin D3 by mouth. In all subjects the concentrations rose in the 24 hours after ingestion. There was little change over the next nine days in the concentrations in the Europeans but those in the Asians continued to rise until about day 10. Subsequent rates of fall in 25-OHD3 were similar in the two groups. Our observations suggest that the low serum concentrations of 25-OHD3 found in Asians are not caused by either impaired intestinal absorption of vitamin D or rapid clearance of 25-ODH3 from the plasma.     

Vitamin D and its metabolites. Advances in the diagnosis and treatment of rickets

Diagnostic and therapeutical uses of vitamin D3 and its metabolites are reviewed. Special emphasis is dedicated to the fetomaternal relationships of 1,25 (OH)2 D3 and 25-OH-D3 at term. The serum levels of 1,25 (OH)2 D3 have been found to be higher in the maternal serum then in the corresponding fetus (85.3 pg/ml and 50.9 pg/ml, respectively). The highest serum levels of 1,25 (OH)2 D3 were found in October and the lowest ones in January showing that there is a dependence on the ultraviolet light. It has been found that there is a correlation between the fetomaternal serum levels of 1,25 (OH)2 D3 and 25-OHD. However, there is no correlation between the serum levels of 1,25 (OH)2 D3 and 25-OHD3, neither in the fetus nor in the mother.     

Reduction of circulating 25-hydroxyvitamin D by antipyrine.

1 Twenty-four Asian vegetarians had significantly lower 25-hydroxyvitamin D (25-OHD) levels and longer antipyrine half-lives than twenty white non-vegetarians (P less than 0.001). 2 Treatment with oral antipyrine over 4 or 5 weeks in seven vegetarian Asians and five racially different non-vegetarians increased drug oxidation significantly in both groups as measured by a fall in antipyrine half-lives and a rise in serum gamma-glutamyltranspeptidase levels and urinary 6 beta-hydroxycortisol/17-hydroxycorticosteroid ratios. 3 Antipyrine treatment produced a fall in circulating 25-hydroxyvitamin D of around 60% in all subjects in whom pretreatment levels could be measured, independent of race and diet. 4. In the Caucasian non-vegetarian group 1,25 dihidroxyvitamin D levels, the most active metabolite of vitamin D, were also measured and remained unaltered despite a substantial fall in 25-hydroxy substrate. 5 The acute fall in 25-hydroxyvitamin D concentration with a maintained level of 1,25 dihidroxyvitamin D may represent the early changes of drug-induced osteomalacia.     

Diet, sunlight, and 25-hydroxy vitamin D in healthy children and adults.

In 110 white West Midlands children serum 25-hydroxy vitamin D (25-OHD) concentrations showed a pronounced seasonal variation, the values being highest in August and lowest in February. The concentrations correlated significantly both with recorded sunlight and with seasonal ultraviolet energy of the sunlight. Children who had had a seaside holiday the previous summer had a higher mean 25-OHD concentration than those who had not had a summer holiday away from home. Correlation between vitamin D intake and serum 25-OHD concentration was not significant.     

Actions of vitamins D2 and D3 and 25-OHD3 in anticonvulsant osteomalacia.

In 54 epileptic outpatients treated for at least one year with anticonvulsants the bone mineral content (B.M.C.), an estimate of total body calcium, and serum calcium were measured before and during treatment with three doses of cholecalciferol (vitamin D3; 200, 100, and 50 mu-g daily) and 25-hydroxycholecalciferol (25-OHD3; 40, 20, and 10 mu-g daily) for 12 weeks. The results, when compared with the effects of calciferol (vitamin D2; 200, 100, and 50 mu-g daily) in 40 epileptic outpatients, showed different actions in anticonvulsant osteomalacia of vitamin D2 on the one hand and vitamin D3 and 25-OHD3 on the other. In the patients who received vitamin D2 an increase in B.M.C. was found whereas serum calcium was unchanged. The patients who received vitamin D3 or 25-OHD3 showed an increase in serum calcium but unchanged values of B.M.C. The results suggest that liver enzyme induction cannot alone explain anticonvulsant osteomalacia.     

Calcium-phosphorus changes in chronic anticonvulsant therapy: effects of the administration of 25-hydroxyvitamin D3 on secondary hyperparathyroidism

The present study represents a contribution to the knowledge of secondary hyperparathyroidism (SHP) in patients treated with anticonvulsant drugs (AC). In these subjects alterations of the calcium: phosphorus metabolism as rickets and osteomalacia are frequent; however literature data on SHP are scarce. Our research carried out on 29 adult patients under treatment with one or more AC for periods ranging from 9 months to 12 years confirmed that 25-OHD levels in the serum are low, especially in patients treated for longer times. The iPTH levels in the serum are increased with respect to normal controls, while blood calcium and phosphate levels are normal as are urine calcium and phosphate. The 25-OHD levels in serum present the same seasonal variations as the normal controls. The administration of 25-OHD3 (20 micrograms/day for 3 months) to 12 of these patients who had the lowest 25-OHD spring levels rendered the 25-OHD levels attain normal values. Cyclic AMP was normalized; serum and urine calcium and phosphorus and urinary hydroxyproline were not modified significantly. On the basis of the present data it is recommended that chronic AC treatment should be accompanied by long term administration of 25-OHD3 for prophylaxis and/or for treatment of SHP.     

Decreased serum 24,25-dihydroxy vitamin D concentrations in children receiving chronic anticonvulsant therapy.

Serum 24,25-dihydroxy vitamin D (24,25(OH)2D) and 25-hydroxy vitamin D (25-OHD) concentrations and the ratio between the two were measured in 31 Israeli children and adolescents receiving long-term treatment with phenobarbitone or phenytoin and in controls. 24,25 (OH)2D concentrations were significantly depressed in the patients, although the 25-OHD concentrations were similar to those in the healthy controls. In four patients with radiological evidence of osteopenia very low serum 24,25(OH)2D concentrations and serum 24,25(OH)2D: 25-OHD ratios were recorded. The findings suggest that 24,25(OH)2D deficiency may play an important part in the pathogenesis of osteomalacia in patients treated with anticonvulsant drugs and provide further indirect evidence that 24,25(OH)2D is important for normal bone structure.     

Vitamin D and its metabolites in the pollen of pine. Part 5: Steroid hormones in the pollen of pine species

Unconjugated vitamin D and its metabolites were investigated in the pollen of Pinus nigra Ar. and Pinus sylvestris L. by TLC, HPLC and competitive radiochemical determination of 25-hydroxycholecalciferol (25-OHD3). It was found that vitamin D (D2, D3) was present in the pollen in amounts about 2 micrograms/10 g and 25-OHD3, 24,25-dihydroxycholecalciferol [24,25-(OH)2D3] and 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] between 0.1 and 3 micrograms/10 g of pollen, dependent on pollen species and methods.     

Relative contributions of diet and sunlight to vitamin D state in the elderly.

In winter the vitamin D state of elderly people may reach levels associated with osteomalacia, although the disease may not be clinically apparent. A statistical correlation was observed in a group of elderly subjects during the winter between dietary vitamin D intake and vitamin D state, but the intake was generally too low to make a biologically important contribution to maintaining vitamin D concentrations. Ultraviolet light (UVL) is the primary determinant of vitamin D state in summer and winter, in winter owing to the pools of vitamin D built up during the previous summer. Plasma concentrations of 25-hydroxy vitamin D (25-OHD) in winter of 15.0-22.5 nmol/l (6-9 ng/ml) require that the concentration in the previous summer was over 40 nmol/l (16 ng/ml). To maintain plasma concentrations in the elderly above those associated with osteomalacia a mean dietary vitamin D intake of over 5 microgram/day is required. A more physiological approach, however, would be to increase exposure to UVL.     

Nutrition of elderly men living alone. Part 2, Vitamin C and thiamine status.

A dietary survey using the five day record method was carried out on 35 elderly men living alone in the Christchurch area. The mean calculated intake of vitamin C for these men was 31 mg/day. These dietary intakes of vitamin C were significantly correlated with both plasma vitamin C levels and with leucocyte vitamin C levels. Twelve men (34 percent) with lowered dietary intakes of vitamin C were in the range for asymptomatic scurvy. The mean calculated intake of thiamine was 1.05 mg/day. The mean TPP effect was 12.9 percent (n = 27). Dietary intakes of thiamine showed a significant inverse relationship with TPP effect. Eight subjects (23 percent) who too, less than the Australian dietary allowance had an elevated TPP effect. By both dietary and biochemical methods there was evidence of subclinical vitamin C and thiamine deficiencies in more than a quarter of these men.     

Vitamin D status of Asian infants

Vitamin D intakes of infants aged 6 and 18 months from the Asian community in Southhall, Middlesex, were studied to assess the effectiveness of food fortification as a means of preventing vitamin D deficiency. Infants aged 6 months generally had similar diets to white children of the same age and had reasonable vitamin D intakes owing to consumption of fortified dried milks and cereals, reinforced by health visitors and baby clinics. Children aged 18 months, however, ate largely Asian diets and had much lower vitamin D intakes than the 6-month-old group with a corresponding increase in symptoms of vitamin D deficiency. Hence new measures for preventing vitamin D deficiency should probably be aimed at children aged over 1 year. The results of this survey suggest that fortifying chapati flour would be the most effective method of doing this.     

维生素D补充与药物选择

近10多年来,液相色谱-质谱法(LC-MS)已能精确区分且定量测定血清25-羟基维生素D2(25(OH)D2)和25-羟基维生素D3(25(OH)D3)水平,由此发现维生素D3的营养能力优于维生素D2.本文介绍用25-羟基维生素D水平评估维生素D营养状况的理由及定量测定25(OH)D2和25(OH)D3方法的演变过程,...     

维生素D对婴幼儿肺炎的临床价值探讨

目的:探讨婴幼儿肺炎血清25(OH)D3水平的变化及维生素D辅助治疗婴幼儿肺炎的临床疗效。方法:选取我院因肺炎住院的78例婴幼儿作为肺炎组,按临床症状轻重不同分成轻症组和重症组,另外选取儿童保健门诊体检的62例婴幼儿作对照组,测定所有患儿血清25(OH)D3水平。再将肺炎组患儿随机分为维生素D治疗组和非治疗组,两组均给予常规的抗感染以及对症支持治疗,治疗组在常规治疗基础上给予维生素D治疗1周,治疗前及治疗后1周分别检测血清25(OH)D3水平,同时比较两组患儿临床疗效。结果:(1)婴幼儿肺炎组血清25(OH)D3水平低于正常对照组,差异有统计学意义(P<0.01)。(2)重症肺炎组血清25(OH)D3水平低于轻症肺炎组,差异有统计学意义(P<0.01)。(3)治疗7 d后,维生素D治疗组血清25(OH)D3水平高于治疗前,差异有统计学意义(P<0.01)。(4)维生素D治疗组的体温恢复正常时间、咳嗽气喘消失时间、肺部啰音消失时间、住院时间均较非治疗组短,差异有统计学意义(P<0.05)。(5)维生素D治疗组总体有效率97.4%,高于非治疗组的82.1%,差异有统计学意义(P<0.05)。结论:维生素D 缺乏可能是婴幼儿肺炎的诱因之一,在判断疾病轻重上也有一定的意义,维生素D 辅助治疗婴幼儿肺炎可缩短病程、改善疗效。     

骨化三醇对男性酒精性肝硬化患者骨密度和骨代谢的影响

目的：探讨补充骨化三醇对酒精性肝硬化患者骨密度和骨代谢指标的影响。方法：将维生素D缺乏的酒精性肝硬化患者随机分成观察组和对照组,两组常规治疗相同,观察组给予骨化三醇胶丸（0．25μg／d）治疗,比较两组治疗半年后骨密度及β胶原特殊序列（β-CTx）、25-羟维生素D（25-OHD）、血钙、血磷、甲状旁腺激素（PTH）等骨代谢指标的差别。结果：观察组治疗后血磷、PTH均较治疗前显著下降,25-OHD、血钙均较治疗前显著上升,差异均有统计学意义（P〈0．05）;对照组治疗后25-OHD较治疗前显著下降,差异有统计学意义（P〈0．05）;治疗后,观察组血钙和25-OHD显著高于对照组,血磷和PTH显著低于对照组,差异均有统计学意义（P〈0．05）;治疗后,观察组和对照组骨密度、T值、β-CTx和肝功能比较,差异无统计学意义（P〉0．05）。结论：补充骨化三醇半年可改善酒精性肝硬化患者维生素缺乏状态,但未发现能阻止骨破坏和提高骨密度。     

Quantitation of serum 25(OH)D2 and 25(OH)D3 concentrations by liquid chromatography tandem mass spectrometry in patients with diabetes mellitus

Vitamin D has been considered to regulate calcium and phosphorus homeostasis and to preserve skeletal integrity. Serum 25-hydroxyvitamin D (25(OH)D) is the best indicator of vitamin D levels. The association of serum 25(OH)D deficiency with increased risk of type 1 diabetes (T1DM) and type 2 diabetes (T2DM) is controversial. We investigated serum 25(OH)D₂ and 25(OH)D₃ levels in diabetes patients by using liquid chromatography tandem mass spectrometry (LC-MS/MS). Serum 25(OH)D2 and 25(OH)D3 levels were measured with liquid chromatography tandem mass spectrometry in electrospray ionization positive mode. Chromatograms were separated using an ACE5 C18 column on a gradient of methanol. The total 25(OH)D levels were calculated as the sum of 25(OH)D3 and 25(OH)D2 levels. A total of 56 patients with T1DM and 41 patients with T2DM were enrolled in this study. There were 42 and 28 non-diabetic, age-matched volunteers who participated as the T1DM controls and the T2DM controls, respectively. The total 25(OH)D levels were lowest in the 21–40 age group. The levels of both 25(OH)D3 and the total 25(OH)D were significantly higher in the T1DM and T2DM groups than in the controls (p < 0.01 in T1DM and p < 0.05 in T2DM group, respectively). The 25(OH)D2 levels were only significantly higher in T1DM patients than in the controls. The percentages of vitamin D deficiency (total 25(OH)D less than 20 ng/mL) in the T1DM, T2DM, the T1DM controls and the T2DM controls were 7.1%, 0%, 14.3% and 3.6%, respectively. The percentages of vitamin D insufficiency (total 25(OH)D less than 30 ng/mL) in the T1DM, T2DM, the T1DM controls and the T2DM controls were 26.8%, 7.3%, 54.8% and 17.9%, respectively. The percentages of vitamin D deficiency and insufficiency were significantly lower in the T1DM patients than in the T1DM controls (p < 0.01). In the present study, both type 1 and type 2 diabetes patients had higher serum 25(OH)D levels and lower percentages of vitamin D deficiency/insufficiency.     

Using gas chromatography and mass spectrometry to determine 25-hydroxyvitamin D levels for clinical assessment of vitamin D deficiency

Vitamin D is responsible for multiple metabolic functions in humans. Rickets are the most common disease caused by vitamin D deficiency. It is caused by poor calcium intake resulting in poor serum-ionized calcium. The purpose of this study is to develop a rapid, sensitive, and feasible method to determine the 25-hydroxy-vitamin D3 (25(OH)D3) levels in blood samples for clinical assessment. In this study, gas chromatography coupled mass spectrometry with trimethylsilyl derivatization (TMS-GC-MS) is the most suitable protocol for quantitative analyses of 25(OH)D3. Performance of method was evaluated and compared with liquid chromatography and immunoassay. Method validation has been carried out with plasma specimens. The limit of quantitation of TMS-GC-MS method is 1.5 ppb with good linear correlation. Furthermore, the dietary intake and nutritional status of vegetarian and non-vegetarians in Taiwan were assessed by our validated method. As a result, this vitamin D nutrition survey demonstrates that most Taiwanese people have insufficient vitamin D. Due to dietary habits; the male vegans may have the highest risk of vitamin D deficiency.     

儿童哮喘急性发作期血清25-羟基维生素D、总IgE水平变化及临床意义

目的 探讨儿童哮喘急性发作期血清25-羟基维生素D、总IgE水平变化及与疾病严重程度的关相关性.方法 选取2014年6月至2015年12月本院儿科门急诊及住院的66例哮喘患儿以及30例同期健康幼儿为研究对象,分别采用电化学发光法及免疫放射分析法测定其血清25-羟基维生素D及血清总IgE水平.结果 三组哮喘急性发作期不同患病程度的哮喘患儿血清25-羟基维生素D水平较对照组均降低,而血清总IgE水平均升高,差异有统计学意义(P＜0.05);且随着疾病进程,其血清25-羟基维生素D水平降低而总IgE水平增高.相关性分析结果表明,缓解组及轻度组患儿血清25-羟基维生素D与血清总IgE水平不相关(r=0.207,P=0.112;r=0.127,P=0.251);中重度患儿血清25-羟基维生素D与血清总IgE水平呈现负相关(r=-0.698,P＜0.05).结论 哮喘患儿血清25-羟基维生素D及总IgE参与哮喘急性发作进程,且两者呈现负相关,提示25-羟基维生素D对IgE有抑制作用.     

Regulation of sodium, calcium and vitamin D metabolism in Dahl rats on a high-salt/low-potassium diet: genetic and neural influences

1. A dietary combination of high salt and low potassium (HSLK) exacerbates hypertension in Dahl salt-sensitive (DS) rats and renders previously normotensive Dahl salt-resistant (DR) rats hypertensive. In both strains, the severity of hypertension correlates with urinary calcium loss. However, the magnitude of excretory calcium losses is significantly greater in DS rats and is potentiated by chemical sympathectomy in both strains. 2. We hypothesized that a defect in vitamin D metabolism may underlie the observed strain-dependent differences in calcium balance. 3. Arterial blood pressure (ABP), water and mineral balance and serum concentrations of 1,25-dihydroxyvitamin D3 (1,25(OH)2 D3) and 25-hydroxyvitamin D3 (25(OH)D3) were measured in intact and chemically sympathectomized (6-hydroxydopamine; 6-OHDA) DS and DR rats after 8 weeks on a HSLK diet. 4. Chronic ingestion of this diet resulted in marked and moderate levels of hypertension in DS and DR rats, respectively. The hypertension was abated and eliminated by 6-OHDA in the DS and DR strains, respectively. Independent of treatment, DS rats had significantly higher urinary excretion of calcium and reduced intestinal absorption of the ion compared with DR rats. The DS rats had significantly higher serum levels of 1,25(OH)2 D3 and markedly lower serum levels of 25(OH)D3 than DR rats. Chemical sympathectomy tended to increase 1,25(OH)2 D3 and to decrease 25(OH)D3 levels in both strains. 5. These data indicate a genetic difference in vitamin D metabolism between DS and DR rats. The abnormally elevated levels of 1,25(OH)2 D3 in DS rats may be an appropriate compensatory response to excessive excretory calcium loss and reduced target organ sensitivity to the hormone and may, maladaptively, directly contribute to hypertension, by stimulating vascular smooth muscle contractility.     

Absorption of a pharmacological dose of vitamin D3 from two different lipid vehicles in man: comparison of peanut oil and a medium chain triglyceride

The absorption of a pharmacological dose of vitamin D3 from two different lipid vehicles, peanut oil, containing long chain fatty acids, and a medium chain triglyceride was compared. Serial measurements of the serum concentration of vitamin D3 after dosage were made. The serum levels of 25-hydroxyvitamin D3, the major circulating vitamin D3 metabolite, were also determined. The analytical methods used were based on HPLC. In the fasting state, the serum levels of vitamin D3 were significantly higher after administration in peanut oil than after administration in the medium chain triglyceride. When the vitamin D3 dose was ingested together with food no difference between the two formulations was observed. Only small inter-formulation differences in serum 25-hydroxyvitamin D3 levels were detected. The results indicate that the presence of long chain fatty acids facilitates the absorption of vitamin D3.     

Vitamin D, cognitive dysfunction and dementia in older adults

The physiologically active form of vitamin D, 1,25-dihydroxyvitamin D(3), is a fat-soluble steroid hormone with a well established role in skeletal health. A growing body of evidence suggests low vitamin D levels also play a role in the pathogenesis of a wide range of non-skeletal, age-associated diseases including cancer, heart disease, type 2 diabetes mellitus and stroke. Low levels of serum 25-hydroxyvitamin D [25(OH)D], a stable marker of vitamin D status, are also associated with increased odds of prevalent cognitive dysfunction, Alzheimer's disease and all-cause dementia in a number of studies, raising the possibility that vitamin D plays a role in the aetiology of cognitive dysfunction and dementia. To date, the majority of human studies reporting associations between vitamin D and cognition or dementia have been cross-sectional or case-control designs that do not permit us to exclude the possibility that such associations are a result of disease progression rather than being causal. Animal and in vitro experiments have identified a number of neuroprotective mechanisms that might link vitamin D status to cognitive dysfunction and dementia, including vasoprotection and amyloid phagocytosis and clearance, but the clinical relevance of these mechanisms in humans is not currently clear. Two recent, large, prospective studies go some way to establish the temporal relationship with cognitive decline. The relative risk of cognitive decline was 60% higher (relative risk?=?1.6, 95% CI 1.2, 2.0) in elderly Italian adults with severely deficient 25(OH)D levels (<25?nmol/L) when compared with those with sufficient levels (≥75?nmol/L). Similarly, the odds of cognitive decline were 41% higher (odds ratio?=?1.4, 95% CI 0.9, 2.2) when elderly US men in the lowest quartile (≤49.7?nmol/L) were compared with those in the highest quartile (≥74.4?nmol/L). To our knowledge, no prospective studies have examined the association between 25(OH)D levels and incident dementia or neuroimaging abnormalities. The possible therapeutic benefits of vitamin D have attracted considerable interest as over 1 billion people worldwide are thought to have insufficient 25(OH)D levels and these levels can be increased using inexpensive and well tolerated dietary supplements. However, no large randomized controlled trials have yet examined the effect of vitamin D supplements on cognitive decline or incident dementia. Further studies are urgently needed to establish which mechanisms have clinical relevance in human populations and whether vitamin D supplements are effective at minimizing cognitive decline or preventing dementia.