Maternal vitamin D deficiency and vitamin D supplementation in healthy infants

The objective of this study was to evaluate the common effects of maternal vitamin D deficiency, various doses of vitamin D given to newborns and the effects of these on vitamin D status in early childhood. Seventy-eight pregnant women and 65 infants who were followed up in various health centers were included in the sudy. 25-hydroxyvitamin-D (25-OHvitD), calcium (Ca), phosphorus (P) and alkaline phosphatase levels were measured in blood samples drawn from pregnant women in the last trimester. Infants born to these mothers were given 400 or 800 IU of vitamin D subsequently at the start of the second week. 25-OHvitD, Ca, P and alkaline phosphatase levels of the 65 infants who were brought in for controls (May-September 2000) were measured and hand-wrist X-rays were evaluated. We analyzed the relationship between vitamin D status of the mothers and infants and socio-economic status; mothers' dressing habits (covered vs uncovered), educational level, and number of pregnancies; and sunlight exposure of the house. Covered as a dressing habit meant covering the hair and sometimes part of the face and wearing dresses that completely cover the arms and legs. In 40 infants who were breast-fed and received the recommended doses of vitamin D on a regular basis, the relationship between serum vitamin D levels and supplementation doses given was analyzed. Serum 25-OHvitD level of the mothers was 17.50 +/- 10.30 and 94.8% of the mothers had a 25-OHvitD level below 40 nmol/L (below 25 nmol/L in 79.5%). The risk factors associated with low maternal 25-OHvitD were low educational level (p = 0.042), insufficient intake of vitamin D within diet (p = 0.020) and "covered" dressing habits (p = 0.012). 25-OHvitD level of the infants was 83.70 +/- 53.70 nmol/L, and 24.6% of the infants had 25-OHvitD levels lower than 40 nmol/L. Risk factors for low 25-OHvitD levels in infants were a) not receiving recommended doses of vitamin D regularly (p = 0.002) and b) insufficient sunlight exposure of the house (p = 0.033). There was a pour but significant correlation between maternal vitamin D levels and infants' 25-OHvitD levels at four months (r = 0.365, p < 0.05). No significant correlation was found between 25-OHvitD levels and supplementation doses of vitamin D (19 infants were supplemented with 400 IU/day and 21 with 800 IU/day of vitamin D) (p = 0.873). Severe maternal vitamin D deficiency remains a commonly seen problem in Turkey. However, vitamin D deficiency can be prevented by supplementation of vitamin D to newborns (at least 400 IU). Supplementation of 800 IU vitamin D in the areas of maternal vitamin D deficiency has no greater benefits for the infants.     

Treatment of malabsorption vitamin D deficiency myopathy with intramuscular vitamin D

A nearly 5 year-old boy presented with proximal muscle weakness, reduced muscle bulk, a positive Gower sign and Trendelenburg gait. He was known to have cholestatic liver disease. Investigations revealed markedly low serum total calcium, elevated alkaline phosphatase, very low serum 25-hydroxyvitamin D, and radiographs consistent with active rickets despite the ongoing administration of a water-soluble preparation of vitamin D. Only i.v. calcitriol acutely corrected the hypocalcemia, despite trying several oral preparations, suggesting that malabsorption secondary to chronic liver disease was the cause of his rickets. Intramuscular calciferol quickly corrected his muscle weakness and X-ray findings. Myopathy secondary to vitamin D deficiency is an uncommon diagnosis in children. Intermittent calciferol is an inexpensive and practical treatment for vitamin D deficiency, especially if associated with malabsorption.     

Vitamin D metabolism in biliary atresia: intestinal absorptions of 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3

In children with biliary atresia, defective intestinal absorption of vitamin D and impaired hepatic uptake and 25-hydroxylation of vitamin D lead to a deficiency of vitamin D and rickets. We recently observed severe rickets in a 3-year-old boy with corrected biliary atresia resulting in jaundice, despite oral treatment with 1 alpha-hydroxyvitamin D3 (1 alpha-OHD3) or 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]. He had low 25-hydroxyvitamin D (25-OHD) and high 1,25-(OH)2D serum levels. Intramuscular vitamin D2 administration produced radiological and biochemical evidence of recovery. Oral 1,25-(OH)2D3 (0.1 microgram/kg) and 25-OHD3 (10 micrograms/kg) tolerance tests were done to assess the ability to absorb vitamin D and the effectiveness of using these drugs orally. Eleven children with corrected biliary atresia, aged 9 months to 7 years, were studied. In oral 1,25-(OH)2D3 tolerance tests, the increments above the baseline serum levels of 1,25-(OH)2D were 140.7 +/- 27.4 pg/ml in nonjaundiced patients (n = 5). In jaundiced patients (n = 3), 1,25-(OH)2D3 absorption in two patients with high basal 1,25-(OH)2D values was lower than that of nonjaundiced patients; however, the absorption in the third patient with a low basal value was similar to that of nonjaundiced patients. In oral 25-OHD3 tolerance tests, the mean increase of serum 25-OHD was 48.9 +/- 30.6 ng/ml in nonjaundiced patients (n = 5) and 23.7 +/- 9.5 ng/ml in jaundiced patients (n = 4), the peak serum 25-OHD levels being reached 6-12 h after 25-OHD3 loading.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vitamin D intoxication

Vitamin D intoxication (VDI) may result from supplementation rarely, but it has been reported more frequently in recent years. This may be attributable to an increase in vitamin D supplement intake due to an understanding of the role of vitamin D (25OHD) in the pathogenesis of several diseases. The symptoms and findings associated with VDI are closely related to serum calcium concentration and duration of hypercalcemia. In patients with VDI, hypercalcemia, normal or high serum phosphorus levels, normal or low levels of alkaline phosphatase (ALP), high levels of serum 25OHD, low serum parathyroid hormone (PTH), and high urine calcium/creatinine are usually present. Serum 25OHD levels above 150 ng/ml are considered as VDI. The main goal of treatment for VDI is correction of the hypercalcemia. When the calcium concentration exceeds 14 mg/dl, emergency intervention is necessary because of the adverse effects of hypercalcemia on cardiac, central nervous system, renal, and gastrointestinal functions. However, since vitamin D is stored in fat tissues, effects of toxicity may last for months despite the removal of the exogenous source of vitamin D. Treatment for VDI includes: discontinuation of intake, a diet with low calcium and phosphorus content, intravenous hydration with saline, loop diuretics, glucocorticoids, calcitonin, and bisphosphonates. In conclusion, the diagnosis of vitamin D deficiency rickets (VDDR) without checking serum 25OHD level may cause redundant treatment that leads to VDI. All patients who are clinically suspected of VDDR should be checked for serum vitamin D status and questioned for previous vitamin D administration before starting vitamin D therapy. On the other hand, parents of all infants should be asked whether they are using dietary or oral supplements, and serial questioning may be required during supplementation to avoid excessive intake.     

维生素D及其受体与临床相关疾病的研究

维生素D(Vitamin D,VitD)对人类健康特别是儿童健康具有重要意义,VitD缺乏性佝偻病是我国儿童重点防治的四病之一。临床发现VitD缺乏性佝偻病除骨骼病变外,同时可影响神经、肌肉、造血及免疫等组织器官的功能。近年来对VitD的研究取得了重大进展。     

Perorale Dünndarmschleimhautsaugbiopsien

From 1969 to 1973 171 peroral intestinal biopsies were carried out at the Children's Hospital Tübingen using the Crosby-Kugler capsule and the Watson intestinal biopsy capsule of paediatric size. The dissecting microscope findings were compared with the histological findings. The former correlated in stage II and III, according to the Shmerling scale, with the histological findings. Findings under the dissecting microscope, stage I, did not correlate in all cases with the histological findings. It is supposed that this results from either an inaccurate orientation or from inadequate sectioning. The plane of sectioning must be parallel to the villi. If the plane of sectioning is not parallel to the villi, the slender villi under the dissecting microscope look like plump villi when examined histologically. It is supposed that this results in a greater number of plump villi and a smaller number of slender villi in the histological findings compared with the dissecting microscope findings. The correspondence of slender villi examined under the dissecting microscope and those which are histologically examined is about 25 to 100%.     

Vitamin D metabolites (25-hydroxyvitamin D, 24,25-dihydroxyvitamin D and 1,25-dihydroxyvitamin D) and osteocalcin in β-thalassaemia

Serum levels of the vitamin D metabolites 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D. and of osteocalcin. C-tenninal parathyroid hormone and other biochemical indices related to bone metabolism, were determined in two groups of patients with β-thalassaemia aged 5–10 years (summer 7.8 ± 0.4 years, mean ± SEM. and winter 7.7 ± 0.4 years, group A, n= 15) and 11–23 years (16.6 ± 0.9 and 15.7 ± 0.9 years in summer and winter, respectively, group B, n= 22). Emphasis was given to populations of school and adolescent ages and to the seasons of summer and winter when vitamin D status demonstrates the widest extremes. The mean serum levels of 25-hydroxyvitamin D in patients aged 5–10 years did not differ from those of controls during both seasons studied. In contrast, in the age group 11–23 years these levels were found to be lower in patients than in controls both in winter (10.6 ± 0.9ng/ml vs 15.0 ± 2.0ng/ml, p < 0.05) and summer (20.2 ± 2.1 ng/ml vs 27.1 ± 2.0ng/ml, p < 0.05). The serum concentrations of 24,25-dihydroxyvitamin D were lower in the thalassaemic patients than in controls in both age groups and both seasons. In the patients under 10 years of age the mean values of this metabolite in winter were 1.06 ± 0.17 ng/ml vs 1.68 ± 0.20 ng/ml in the respective controls (p < 0.05), and in summer 1.44 ± 0.11 ng/ml vs 2.35 ± 0.36 ng/ml in controls (p < 0.05). In the group of patients aged 11–23 years, the mean levels of 24,25-dihydroxyvitamin D were in winter 0.65 ± 0.12 ng/ml vs 1.12 ± 0.19 ng/ml (p < 0.05) in controls and in summer 1.34 ± 0.12 ng/ml vs 1.84 ± 0.20 ng/ml (p < 0.05). The 1,25-dihydroxyvitamin D concentrations in both thalassaemic patient groups were significantly no different from those in the respective control groups. Serum osteocalcin, C-terminal parathyroid hormone, calcium, inorganic phosphate and alkaline phosphatase levels in the patients studied were not significantly different from those in controls, except for calcium and phosphate in the older group. In the older group of thalassaemic patients, serum calcium was lower than in the controls (2.26 ± 0.03 vs 2.37 ± 0.03 mmol/1, p < 0.05) in summer and serum phosphate higher than in the controls in winter (1.47 ± 0.05 mmol/1 vs 1.27 ± 0.06 mmol/1. p < 0.05).     

Response to crystalline 1alpha-hydroxyvitamin D3 in vitamin D dependency.

The therapeutic response to chemically synthesized 1alpha-hydroxycholecalciferol (1alpha-OH-D3) was studied in three patients with autosomal recessive vitamin D dependency (ARVDD). The daily maintenance dose for vitamin D2, to prevent signs of vitamin D deficiency in these patients, was 40-54.4 mug/kg, or about 100 times normal (Table 1). Withdrawal of maintenance therapy with vitamin D2 resulted in the ultimate reappearance of the vitamin D depletion syndrome in patients 1 and 2 (Figs. 1 and 2). The third patient presented with the deficiency syndrome despite adequate vitamin D nutrition and was recognized to have ARVDD. Treatment with 1alpha-OH-D3 by mouth in all three patients at dose levels of 1-3 mug/24 hr (80-100 ng/kg) corrected hypocalcemia and suppressed parathyroid hormone-dependent renal loss of amino acids (Figs. 1, 2, and 4). Rickets healed in 7-9 weeks on 1alpha-OH-D3 alone (Fig. 3). The therapeutic response was rapid. It was usually seen first in the rise of serum calcium (Figs. 5 and 6). Withdrawal of 1alpha-OH-D3 was followed first by a fall of serum phosphorus, then by a fall in serum calcium; the latter occurred within about 2 weeks of withdrawal. Because the synthesis of 1alpha-OH-D3 is simpler than for 1alpha,25-dihydroxycholecalciferol and because the former is an effective therapeutic analog of vitamin D hormone, we believe these studies in ARVDD reveal 1alpha-OH-D3 to be the agent of choice for treatment of this and analogous diseases.     

Type III D mucopolysaccharidosis (Sanfilippo D): Clinical course and symptoms

Abstract A case of a rare form of Sanfilippo disease, mucopolysaccharidosis type III D is presented. The cause of the disease is a deficit of N-acetylglycosamine-6-sulfate sulfatase. Differences in clinical course and symptoms with type A and B Sanfilippo disease are shown (later presentation of symptoms, milder course, lack of distinct psychomotor regression and differences in characteristic phenotypic traits, such as facial features, joint contracture, tall height). It is suggested that type III D mucopolysaccharidosis be taken into account in the differentiation of mental retardation syndromes with hyperactivity.     

维生素D受体基因多态性与佝偻病易感性的研究进展

维生素D缺乏性佝偻病（简称佝偻病）是由于儿童体内维生素D不足引起钙、磷代谢紊乱,使正在生长的骨骼在成骨过程中不能正常沉着钙盐而产生的一种以骨骼病变为特征的全身慢性营养性疾病。目前认为环境因素,主要包括营养因素等是其主要致病原因,但遗传因素在其发生发展中的作用正逐渐受到重视。     

维生素D受体基因多态性与维生素D缺乏性佝偻病的关系

维生素D缺乏性佝偻病(简称佝偻病)是由于儿童体内维生素D不足引起钙、磷代谢紊乱,使正在生长的骨骼在成骨过程中不能正常沉着钙盐而产生的一种以骨骼病变为特征的全身慢性营养性疾病.目前认为环境因素及营养因素等是主要致病原因,但遗传因素在其发生发展中的作用正逐渐受到重视.维生素D是人体内钙稳态和骨代谢的主要调节因子之一,其在体内的主要活性代谢产物是1,25-(OH)2D3.维生素D受体(vitamin D receptor,VDR)是介导1,25-(OH)2D3发挥生物学效应的核内生物大分子,VDR是由VDR基因编码,因此VDR基因是研究骨代谢性疾病遗传基础的候选基因之一.文章就VDR基因多态性与佝偻病遗传易感性之间的关系作一综述.     

维生素D及其受体与佝偻病的研究进展

维生素D通过维生素D受体介导,在体内具有广泛的生物学作用,其中对钙磷代谢的调节作用对于正常的骨骼形成与骨矿化有重要影响.佝偻病为常见的儿童骨代谢性疾病,不同类型佝偻病的病因不同,但其病理生理过程、临床表现及治疗均与维生素D及其受体对骨代谢的影响密切相关.