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Vitamin-D deficiency rickets in Jamaican children.

Vitamin-D deficiency is not as rare in Jamaica as previously believed. 9 children with vitamin-D deficiency rickets have been seen at the University Hospital of the West Indies during the past 5 years. All were over 3 years of age at time of presentation. Both dietary deficiency of vitamin D and lack of exposure to sunlight seem to be important causes. Children living in rural Jamaica seem to be more susceptible to the disease than those living in a city, due perhaps to more prolonged breast feeding and lack of fortified milk feeds on weaning.

Black or African American

An estimation of the parathyroid hormone secretion rate in vitamin D deficient rats.

In an attempt to define the rate of endogenous secretion of parathyroid hormone in vitamin D deficiency, graded amounts of hormone were infused constantly into vitamin D deficient and vitamin D fed acutely thyroparathyroidectomized rats in a perfusion balance study. The dose of hormone needed to compensate for acute thyroparathyroidectomy was estimated. Serum levels of calcium and phosphorus, renal clearances of phosphorus and urinary excretion of cyclic AMP, each determined 16 hr after the surgery, were employed as parameters of the hormone effect. It was concluded that, in the condition of the perfusion balance study, the secretion rate of parathyroid hormone was 5.1-8.6 USP u/hr in the vitamin D deficient animals compared with 0.81-0.84 USP u/hr in the control.

Animals

[Vitamin D deficiency and osteomalacia in old people (author's transl)].

The frequency and causes of vitamin D deficiency in old age were investigated in 53 hospital patients, 88 persons from old people's homes, 21 tenants of a hostel, and 29 members of a seniors meeting group, aged between 65 and 93 years. In all persons 25-hydroxyvitamin D, calcium, phosphate, alkaline phosphatase, leucine arylamidase and creatinine were determined. In 27 cases immunoreactive parathormone was measured. In hospital patients there was evidence of vitamin D deficiency significantly more frequently as compared with the other groups. The 25-hydroxyvitamin D concentration was on average lower in the cases from old people's homes and hostels than in the members of the seniors group. The results in the groups investigated showed a relation to the average exposure to the sun. The results in 10 further patients in this age group with florid osteomalacia indicate a multifactorial aetiology of vitamin D deficiency disease due to reduced exposure to sun, inadequate nutrition and reduced absorption of vitamin D.

Age Factors

Treatment response variations to a single large bolus of enteral cholecalciferol in vitamin D deficient critically Ill children: Metabolomic insights for precision nutrition.

Vitamin D deficiency (VDD) is prevalent globally and in pediatric intensive care units, where it represents a modifiable risk factor that may impact patient recovery during hospitalization. Herein, we performed a retrospective analysis of serum samples from a phase-II randomized placebo-controlled trial involving a single large bolus of 10,000 IU/kg vitamin D3 ingested by critically ill children with VDD (25-OH-D < 50 nmol/L). Targeted and untargeted methods were used to comprehensively measure 6 vitamin D metabolites, 239 lipids, 68 polar metabolites, and 4 electrolytes using a multi-step data workflow for compound authentication. Complementary statistical methods classified circulating metabolites/lipids associated with vitamin D repletion following high-dose vitamin D3 intake (n&#x202f;=&#x202f;20) versus placebo (n&#x202f;=&#x202f;11) comprising an optional standard of care maintenance dose (< 1000 IU/day). There was a striking increase in median serum concentrations of 25-OH-D3 (4.7-fold), 3-epi-25-OH-D3 (24-fold) and their C3-epimer ratio (6.7-fold) in treated patients on day 3, whereas serum vitamin D3 peaked on day 1 (128-fold) unlike placebo. Treatment response differences were attributed to D3 bioavailability and C3-epimerase activity without evidence of hypercalcemia. For the first time, we report the detection of circulating 3-epi-D3 that was strongly correlated with vitamin D3 uptake (r&#x202f;=&#x202f;0.898). Metabolomic studies revealed that vitamin D sufficiency (serum 25-OH-D >75 nmol/L) coincided with lower circulating levels of 3-methylhistidine, cystine, S-methylcysteine, uric acid, and two lysophosphatidylcholines 7 days after treatment. Rapid correction of VDD was associated with indicators of lower oxidative stress, inflammation, and muscle protein turn-over that may contribute clinical benefits in high-risk critically ill children.

Humans

[Erythrocyte metabolism in vitamin D deficiency rickets].

In an attempt to explain the hemolysis observed in vitamin D deficiency rickets in the infant, we studied erythrocytic glycolysis, the level of ATP and some of the key enzymes of the glycolytic pathway. This study was performed in one group of vitamin D deficient infants and in one control group. The values obtained in these two groups did not differ significantly. In the absence of a defect in the glycolytic pathway, we suggest that an anomaly exists in the red cell membrane of these patients.

Adenosine Triphosphate

[Effects of 1,25(OH)2D3 on bone mineralization in vitamin D deficiency (author's transl)].

Two cases with vitamin D-deficient osteomalacia of digestive origin (coeliac disease) have been treated orally with 1,25(OH)2D3 in dosages of respectively 8 and 3 microgram/24 h. Serial transiliac bone biopsies have been performed. Mineralization fronts were normalized after respectively 4 and 1.5 months, whereas mineralization rates, as demonstrated by double tetracycline labeling, were normalized respectively after 2 and 1.5 months. In both cases osteomalacia healed completely despite persistently low 25(OH)D levels in the serum. It is obvious from these studies that 1,25(OH)2D3 per se is able to cure vitamin D-deficient osteomalacia, a finding that has been disputed. Whether 25(OH)D acts more rapidly on bone, as suggested by the studies performed in one case with anticonvulsant osteomalacia, remains to be proven.

Bone and Bones

[Renal acidification disturbance in vitamin D deficiency (author's transl)].

Extensive studies of renal acidification process have been performed in states of vitamin D deficiency. Results show that the process of hydrogen ion excretion is strongly impaired on the entire length of the nephron. Vitamin D and parathyroid hormone probably interfere within tubular cells regulating the concentration of calcium and cyclic AMP; the modification of such an equilibrium carried out by vitamin D deficiency would explain the renal dysfunction.

Bicarbonates

Plasma vitamin D-binding globulin in vitamin D deficiency, pregnancy and chronic liver disease.

Plasma concentrations of vitamin D-binding globulin were measured by radial immunodiffusion in healthy subjects, pregnancy, and during oestrogen therapy. Subjects with disorders of vitamin D metabolism (dietary deficiency, malabsorption, anticonvulsant therapy, chronic liver disease) were also studied. Neither sex nor age influenced the plasma vitamin D-binding globulin concentration in healthy subjects, but there was a significant increase in concentration during pregnancy and oestrogen therapy. Elevated levels were found in vitamin D deficient elderly but not younger subjects, while levels in subjects with chronic liver disease were significantly reduced. Normal levels of vitamin D-binding globulin were present in hypervitaminosis D and no vitamin D-binding globulin was detected in human milk. No correlation was observed between plasma 25-hydroxycholecalciferol levels and plasma vitamin D-binding globulin concentrations.

Adult

Prevalence and determinants of profound vitamin D deficiency (25-hydroxyvitamin D <10 nmol/L) in the UK Biobank and potential implications for disease association studies.

BACKGROUND: 25-hydroxyvitamin D (25OHD) is the principal biomarker of vitamin D status. Values below the assay detection limit (<10 nmol/L) are often reported as missing. Thus the most severely deficient participants are excluded from research which can lead to inaccurate findings such as underestimated prevalence of deficiency, overlooked risk factors, and biased evaluation of disease associations. METHODS: In total 369,626 individuals from the UK Biobank cohort were included in this study. Data on 25OHD concentration and relevant demographic and lifestyle factors such as age, supplement intake, diet, and time spent outdoors were used in the analyses. Ambient UVB radiation was approximated for each participant. 25OHD was evaluated as a categorical outcome and we reintroduced participants with 25OHD values <&#x202f;10 nmol/L (conventionally reported as missing values) back to the dataset. Adjusted regression models were used to investigate the determinants of profound (25OHD <10 nmol/L) and severe (10-25 nmol/L) vitamin D deficiency and to assess disease associations (with 25-50 nmol/L as the reference category). RESULTS: 1,784 (0.48&#x202f;%) individuals were profoundly deficient and a further 47,226 (12.78 %) individuals were severely vitamin D deficient. The proportions of profoundly and severely deficient were highest among Asians, 9&#x202f;% and 47&#x202f;%, respectively. Ambient UVB radiation was the second strongest predictor: comparing the lowest vs. highest quartile, the risk of profound deficiency was 17-fold increased and that of severe deficiency 7.5-fold increased. Use of vitamin D supplements substantially reduced risk of profound (4.4-fold) and severe (2.5-fold) deficiency, as did fish intake (5- and 1.9-fold, respectively). Profound deficiency was more strongly associated with chronic illness, diabetes, and emphysema compared to severe deficiency. CONCLUSION: The prevalence of profound and severe vitamin D deficiency among Asian and Black ethnicities in the UK is high and requires targeted action. Solar radiation is potent in protecting against profound and severe vitamin D deficiency. Studies evaluating the relationship between vitamin D status and other health outcomes may be biased if profoundly deficient participants are excluded.

Humans

[Vitamin D deficiency in femoral neck fractures (author's transl)].

In a therapeutic trial 20 patients with femoral neck fractures (FNF) were treated alternatively without supplemental vitamin D, calcium and phosphate or with 15 000 I.U. vitamin D2, 500 mg Ca++ and 560 mg of phosphate daily. Within two weeks, 25-OH-D in serum increased in patients with supplementary therapy. It is concluded that in the German Federal Republic, vitamin D deficiency is frequently found in the elderly during the winter months and that vitamin D deficiency could be important for the development of FNF.

Aged

Studies of vitamin D deficiency in man.

Highly sensitive assays have been developed that enable 25-hydroxycholecalciferol (25-hydroxyvitamin D3) and 25-hydroxyergocalciferol (25-hydroxyvitamin D2) to be measured in the same serum sample. With these assays it has been shown that endogenously produced cholecalciferol (vitamin D3) is important in man; the findings further emphasize the role of vitamin D metabolites as hormones rather than vitamins in the traditional sense. Dietary sources of vitamin D appear to be inadequate and vitamin D deficiency has been shown to the cause of rickets and osteomalacia in Asian immigrants to Britain. This condition may be readily treated with small doses of vitamin D. In addition, sub-clinical deficiency was found in the Asian community. In the elderly, also, vitamin D deficiency was established as an important cause of osteomalacia and again evidence for the existence of a sub-clinical deficiency state was found. It is therefore suggested that the present prophylactic practices should be reviewed. Secondary hyperparathyroidism (reflected by elevated concentrations of circulating immunoassayable parathyroid hormone) was shown to be the rule rather than the exception in vitamin D deficiency. Some patients, however, had failed to respond to a hypocalcaemic stimulus. In others, there were high concentrations of parathyroid hormone despite normal serum calcium concentrations. Thus the relationship between parathyroid hormone and metabolites of vitamin D may not be mediated through changes in serum calcium alone, and it is postulated that metabolites of vitamin D may directly affect the secretion of parathyroid hormone.

Adolescent

Vitamin D deficiency and reproduction in rats.

Female weanling rats from a colony maintained on a diet low in vitamin D were raised on a diet that was deficient in vitamin D but was otherwise adequate. Vitamin D deficiency was confirmed in the rats by hypocalcemia and the absence of vitamin D metabolites in blood. These females gave birth to litters that were slightly smaller than control litters from females maintained on a vitamin D-containing diet. The pups from the vitamin D-deficient mothers appeared normal throughout lactation, and at weaning had normal concentrations of calcium and phosphate in the plasma. These results indicate that vitamin D and its metabolites are not necessary for reproduction and fetal development in the rat.

Animals

An outbreak of vitamin D deficiency rickets in a susceptible population.

Nutritional, racial, cultural, and environmental factors have combined to produce a resurgence of vitamin D deficiency rickets in urban Philadelphia. Between January 1974 and June 1978, 24 cases were diagnosed at the Children's Hospital of Philadelphia. Patients' ages ranged from 4 to 58 months. Presenting complaints included seizures, swollen wrists, pathologic fractures, and developmental regression. Sixteen patients were below the third percentile for length and weight. Laboratory results indicated vitamin D deficiency in nursing mothers as well as in infants. All infants had been breast-fed and all were black. Ingestion of vitamin D was limited by exclusion of meat and/or dairy products in 21, and no infants had consistently taken supplemental vitamins. Nineteen were members of Muslim or Seventh Day Adventist faiths. Endogenous synthesis of vitamin D was limited by dark skin, by dressing in long garments with hoods and veils, and by air pollution in a densely populated northern city. The return to a more "natural" diet, free of food additives, has been accompanied by the return of a classic disease of industrial society. Effective management required patience and respect for religious convictions. With treatment, there was correction of chemical and skeletal abnormalities, but few patients showed catch-up growth.

Black or African American

Vitamin D Deficiency During Pregnancy Is Associated With Greater LDL-C Increase, Elevated &#x3b2;-Hydroxybutyrate and Altered Neonatal Metabolic Markers-A Secondary, Pooled Analysis of the Randomized, Controlled Vitamin D and Lifestyle for Gestational Diabetes Prevention Trial (DALI).

INTRODUCTION: Vitamin D (vitD) plays a role in metabolic regulation, including lipid metabolism and insulin sensitivity. During pregnancy, profound physiological changes in lipid handling and ketogenesis occur to support fetal development. However, the extent to which maternal vitamin D status influences these metabolic adaptations and fetal metabolic markers remains unclear. METHODS: In this secondary analysis, we examined lipid distribution throughout pregnancy-from before 20&#x2009;weeks' gestation to delivery-in women with overweight or obesity, stratified by vitamin D status (deficiency, insufficiency, or sufficiency), assessing both maternal and cord blood. Main inclusion criteria were: age&#x2009;>&#x2009;=18&#x2009;years, singleton pregnancy, <&#x2009;20&#x2009;weeks' gestation, BMI &#x2265;&#x2009;29&#x2009;kg/m2. Women with GDM <&#x2009;20&#x2009;weeks' gestation were excluded. In total, 962 pregnant women were divided into vitD deficient (<&#x2009;30&#x2009;nmol/L, n&#x2009;=&#x2009;102), insufficient (30-50&#x2009;nmol/L, n&#x2009;=&#x2009;222) and sufficient (>&#x2009;50&#x2009;nmol/L, n&#x2009;=&#x2009;638) groups. VitD levels and lipid concentrations were assessed at <&#x2009;20, 24-28 and 35-37&#x2009;weeks' gestation and in cord blood. RESULTS: Compared with vitD sufficient women, women with vitD deficiency had significantly larger increases in LDL-C throughout pregnancy and &#xdf;-OH-butyrate at 24-28&#x2009;weeks' gestation, in adjusted analysis. VitD in cord blood was highest in offspring of mothers with vitD sufficiency. In cord blood, significantly higher &#xdf;-OH-butyrate was observed with vitD deficiency; lipid concentrations were similar between groups. CONCLUSIONS: Early vitamin D deficiency before 20&#x2009;weeks of gestation was associated with altered metabolic trajectories during pregnancy, including greater increases in LDL cholesterol and ketone body concentrations in women with overweight or obesity, as well as higher cord blood ketone levels in their offspring. These findings suggest that early maternal vitamin D status may influence maternal and fetal metabolic adaptations, although causal relationships and clinical implications require further investigation. TRIAL REGISTRATION: Trial registered at ISRCTN registry (https://doi.org/10.1186/ISRCTN70595832) trial number ISRCTN70595832. Registration date 02/12/2011.

Humans

Parathyroid hormone and calcitonin levels in vitamin D deficient rickets.

In six infants aged between 5 and 8 months with vitamin D deficient rickets, we have studied blood levels of calcium (Ca), phosphorus (P), alkaline phosphatase, immunoreactive parathyroid hormone (PTH) and calcitonin (CT), as well as urinary excretion of Ca, P, hydroxyproline and cyclic AMP, both under basal conditions and during a 4h infusion of 20 mg/kg 10% Ca gluconate in normal saline. Under basal conditions all the infants had high alkaline phosphatase (range: 470--770 U.I./1); PTH (range: 620--1200 pg Eq/ml) and CT (range: 440--750 pg/ml) but two infants had hypocalcaemia and four had normocalcaemia and hypophosphataemia. The urinary Ca excretion was low whereas the urinary P, hydroxyproline and cyclic AMP excretions were high. During Ca infusion the total serum Ca and CT levels increased, while alkaline phosphatase and PTH fell. After the end of the infusion, CT levels fell perceptibly; phosphaturia, hydroxyprolinuria and cyclic AMP decreased on the day of the infusion.

Alkaline Phosphatase

Effect of vitamin D deficiency on sarcoplasmic reticulum function and troponin C concentration of rabbit skeletal muscle.

1. Weanling rabbits were made rachitic either by a vitamin D-deficient diet or by parenteral administration of ethane 1-hydroxy-1,1-diphosphonate (EHDP) in amounts sufficient in other species to block the formation of 1,25-dihydroxycholecalciferol [1,25-(OH)2D3]. 2. The uptake of calcium into the isolated sarcoplasmic reticulum from mixed striated quadriceps muscle, and the amount of troponin C (the calcium-binding component of the troponin complex) in relation to other proteins from the same muscle, were measured. 3. In muscle from animals made rachitic by a dietary deficiency of vitamin D, the rate of uptake of calcium by the sarcoplasmic reticulum and the troponin C concentration were both significantly less (P less than 0.02) than in control littermates. In EHDP-treated animals no significant differences from controls were found. 4. These results show that dietary deficiency of vitamin D in such animals can affect muscle physiology. Since no changes are found in animals made rachitic with EHDP, who presumably have a selective deficiency of 1,25-(OH)2D3, it is possible that the effect of vitamin D on muscle is mediated through metabolites other than 1,25-(OH)2D3 such as 25-hydroxycholecalciferol.

Animals

Interactions between vitamin D deficiency and phosphorus depletion in the rat.

To evaluate the role of vitamin D in the physiologic response to phosphorus depletion (P depleton) and the response to vitamin D administration in P depletion, we studied vitamin D-deficient (-D) rats, fed either a normal or low phosphorus diet and then injected intraperitoneally on alternate days with replacement vitamin D(3), 1.25 mug qod (D(3)); 1.25-dihydroxy-vitamin D(3)[1,25(OH)(2)D(3)] in physiologic, 54 ng qod (LD), and pharmacologic doses, 400 ng qod (HD); or vehicle alone (-D). The following results were obtained: (a) With P depletion, urinary excretion of inorganic phosphorus (Pi) fell to almost undetectable levels in -D rats, and two physiologic features of P depletion a calcemic effect and hypercalciuria, ensued. (b) With administration of vitamin D(3) or 1,25(OH)(2)D(3) in either doses to P-depleted rats, the renal retention of Pi was unaltered despite a significant elevation of serum Pi. (c) The calcemic response to P depletion was accentuated by vitamin D sterols, and the hypercalciuria of P depletion was reduced by 1,25(OH)(2)D(3), HD > LD > D(3). (d) In -D animals receiving normal Pi (+P), D(3), and 1,25(OH)(2)D(3), both LD and HD produced a significant calcemic and phosphatemic effect. (e) Urinary Pi excretion in +P animals was reduced slightly by vitamin D(3) whereas 1,25(OH)(2)D(3), both LD and HD, lowered urinary Pi markedly despite an increased serum Pi. (f) The serial values of serum Ca and Pi and urinary Ca in PD rats and the sequential values for urinary and serum Pi in +P rats indicated more rapid effects of 1,25(OH)(2)D(3), both HD and LD, compared with D(3). We conclude that: (a) The renal adaptation and physiologic response to PD does not require the presence of vitamin D. (b) 1,25(OH)(2)D(3) may directly enhance the renal tubular reabsorption of Pi even as serum Pi rises. (c) A hypocalciuric action of 1,25(OH)(2)D(3) in rats on low phosphorus diet could be direct or occur as a consequence of an increase in serum Pi produced by 1,25(OH)(2)D(3). The different sequential renal response to D(3) compared with 1,25-(OH)(2)D(3) raises the possibility that other natural forms of vitamin D(3) [i.e., 25(OH)D(3), 24,25(OH)(2)D(3), etc.] which may be present in vitamin D-fed rats but not those given only 1,25(OH)(2)D(3), could modify the actions of 1,25(OH)(2)D(3).

Animals

Protein secretion from parotid glands of vitamin D deficient and glucocorticoid-treated rats.

The rate of isoproterenol stimulated secretion of protein from parotid glands of vitamin D deficient rats and rats treated with methylprednisolone was increased compared to the secretory response of tissue from control rats. It is suggested that the increased secretory response is secondary to a decreased capacity of mitochondria from the tissue of these animals to take up and store Ca2+; i.e. the mitochondria are less efficient buffers of cytoplasmic Ca2+. Under these conditions any process, such as protein secretion, which requires an increased cytoplasmic Ca2+ concentration will operate more effectively.

Animals