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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The occurrence of osteoporotic fractures may seriously compromise the quality of life of lung transplant recipients. However, at present, the true risk of osteoporosis in such patients is unknown. We therefore prospectively evaluated bone mass changes in patients undergoing pulmonary transplantation. Bone mineral density (BMD) of lumbar spine (LS), femoral neck (FN) and femoral shaft (FS), as well as whole body bone mineral content (WB-BMC) were measured in 21 consecutive candidates for lung transplantation (9 males and 12 females; mean+/-SD age 47+/-11 yrs). Twelve of the patients had their BMD remeasured within 6 months after surgery, and nine again after 1 year. Before transplantation, BMD at all sites as well as WB-BMC were significantly decreased as compared to the values in young healthy adults, FN being the most affected (FN -25+/-2%; LS, -12+/-4%; FS -9+/-2%, WB-BMC -15+/-4% (mean+/-SEM)). Seven out of 20 adult patients (35%) fulfilled World Health Organization (WHO) criteria for osteoporosis, i.e. BMD more than 2.5 SD below peak bone mass, whereas three had previously been diagnosed as having osteoporotic fractures of the spine or femoral neck. Within 6 months after transplantation, significant bone loss occurred, mostly at the LS level (-4.0+/-1.7%; p=0.04), despite calcium and vitamin D supplementation. Furthermore, two patients had new osteoporotic vertebral fractures. After 1 year, no further bone loss or new osteoporotic fractures were observed. In conclusion, evaluation of bone mass and prevention of bone loss should be considered early before lung transplantation. Further studies are needed to determine the efficacy of antiresorptive drugs on the prevention of accelerated bone loss and vertebral fractures after transplantation.
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PMID:Osteoporosis in patients undergoing lung transplantation. 894 89

Calcitriol, as used for treating secondary hyperparathyroidism, has a low therapeutic index. The safety and efficacy of the vitamin D analog, 1 alpha (OH)-vitamin D2, (1 alpha D2), which has less toxicity in animals than 1 alpha (OH)-vitamin D3, was tested in a multicenter study of 24 hemodialysis patients with secondary hyperparathyroidism [serum intact (i) PTH > 400 pg/ml]. Calcium-based phosphate binders alone were used to maintain serum phosphorus < or = 6.9 mg/dl. After eight weeks without calcitriol (washout), oral 1 alpha D2, 4 micrograms/day or 4 micrograms thrice weekly, was started, with the dose adjusted over 12 weeks to maintain serum iPTH between 130 and 250 pg/ml. Pre-treatment serum iPTH fell from 672 +/- 70 pg/ml (SEM) to 289 +/- 36 after treatment (P < 0.05). The maximal decrease in serum iPTH was 48 to 96%, with 87.5% of patients reaching target iPTH levels. The final dose of 1 alpha D2 average 14.2 micrograms/week. Pre-treatment serum calcium rose modestly from 8.8 +/- 0.2 mg/dl to 9.5 +/0 0.2 after treatment (P < 0.001). Only once did modest hypercalcemia (serum Ca > 11.2 mg/dl) necessitate stopping treatment. Neither the average serum P level, the incidence of hyperphosphatemia, nor the dose of phosphate binders changed from washout to treatment. Thus, oral 1 alpha D2 is highly efficacious in suppressing secondary hyperparathyroidism in hemodialysis patients and is safe despite exclusive use of calcium-based phosphate-binders. Future studies should clarify the optimal dosage regimen.
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PMID:Effective suppression of parathyroid hormone by 1 alpha-hydroxy-vitamin D2 in hemodialysis patients with moderate to severe secondary hyperparathyroidism. 899 49

The aim of this study was to evaluate whether fast trabecular bone loss in osteoporotic and osteopenic patients can effectively be treated with active vitamin D metabolites. Thirty-one osteoporotic and osteopenic patients were monitored between 4 and 22 months before and between 8 and 18 months during the treatment. Fast bone losers were designated as osteoporotic or osteopenic patients with a loss of trabecular bone density in the radius of 3% or more calculated for 1 year. For this differentiation, the high precise peripheral quantitative computed tomography system (DENSISCAN 1000) was used (reproducibility 0.3% in mixed collectives). The pretreatment loss and the "gain" under treatment with active vitamin D metabolites was calculated for 1 year. The treatment consisted of either 0.5 micro;g calcitriol daily or 1 micro;g of alfacalcidol daily. Before treatment, the trabecular bone loss in the radius/year was -6.6 +/- 0.5% (mean +/- SEM). After treatment with vitamin D metabolites, the trabecular bone gain in the radius/year was 0.01 +/- 0.6% (mean +/- SEM). The difference was highly significant (P < 0.001). In contrast to this, the loss of cortical bone density before treatment was -1.8 +/- 0.3% (mean +/- SEM) and the reduced loss after treatment -0.2 +/- 0.4% (mean +/- SEM), both values calculated for 1 year. This difference was less significant (P < 0. 05). This study shows that the treatment with active vitamin D metabolites is very effective in slowing fast trabecular bone loss in osteoporotic and osteopenic patients.
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PMID:Can the fast bone loss in osteoporotic and osteopenic patients be stopped with active vitamin D metabolites? 903 Apr 92

Cardiac transplantation is associated with increased prevalence and incidence of fracture, and rapid bone loss has been reported during the first posttransplant year. To define further the pattern and etiology of bone loss after cardiac transplantation, we enrolled 70 patients (52 men and 18 women) in a prospective 3-yr study. Bone densitometry (BMD) and biochemical indexes of mineral metabolism were performed before and at defined times after transplantation. Despite supplementation with elemental calcium (1000 mg/day) and vitamin D (400 IU/day), the mean rate of bone loss during the first year was 7.3 +/- 0.9% (+/- SEM) at the lumbar spine and 10.5 +/- 1.1% at the femoral neck. The rate of bone loss slowed (P < 0.001 compared to year 1) at both sites (0.9 +/- 0.9% and 0.1 +/- 1.0%, respectively) during the second year. During the third year, lumbar spine BMD increased at a rate of 2.4 +/- 0.8%/yr (P < 0.02 compared to year 2), but femoral neck BMD did not change. At the radius, the rate of decline in BMD was negligible during the first year (0.9 +/- 0.5%), but was significant during the second (2.1 +/- 0.6%; P < 0.01) and third (2.9 +/- 0.8%; P < 0.03) years. Evaluation of the pattern of bone loss during the first year demonstrated that mean lumbar spine BMD decreased rapidly during the first 6 months, after which there was no further decline. In contrast, femoral neck BMD continued to fall at an annualized rate of 8.2 +/- 1.3% during the second half of the year. The pattern and rates of bone loss were similar in men and women. Biochemistries revealed decreases in serum testosterone and osteocalcin and increases in all bone resorption markers 1 and 3 months after transplantation, with a return to baseline by 6 months. Higher rates of bone loss were associated with greater exposure to prednisone, lower serum concentrations of vitamin D metabolites, greater suppression of osteocalcin, higher levels of bone resorption markers, and, in men, lower serum testosterone concentrations. We conclude that rapid bone loss is primarily confined to the initial year after transplantation. During the first 6 months, bone loss is accompanied by alterations in markers of bone turnover consistent with biochemical uncoupling of bone formation and resorption. Greater exposure to glucocorticoids, lower serum concentrations of vitamin D metabolites and testosterone, and higher bone turnover were associated with more rapid bone loss.
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PMID:Bone loss and turnover after cardiac transplantation. 914 40

Serum levels of the vitamin D metabolites 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D, and of osteocalcin, C-terminal parathyroid hormone and other biochemical indices related to bone metabolism, were determined in two groups of patients with beta-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 +/- 0.9 ng/ml vs 15.0 +/- 2.0 ng/ml, p < 0.05) and summer (20.2 +/- 2.1 ng/ml vs 27.1 +/- 2.0 ng/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/l, p < 0.05) in summer and serum phosphate higher than in the controls in winter (1.47 +/- 0.05 mmol/l vs 1.27 +/- 0.06 mmol/l, p < 0.05).
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PMID:Vitamin D metabolites (25-hydroxyvitamin D, 24,25-dihydroxyvitamin D and 1,25-dihydroxyvitamin D) and osteocalcin in beta-thalassaemia. 920 93

Osteoporosis and fractures are increasingly recognized in children and adults with cystic fibrosis. To investigate the prevalence and pathogenesis of osteoporosis and low bone mass in adults with advanced pulmonary disease due to cystic fibrosis, we examined the relationships between bone mineral density (BMD), anthropomorphic variables, pulmonary status, glucocorticoid therapy, and vitamin D concentrations. BMD of the lumbar spine, hip, and proximal radius was measured by dual energy X-ray absorptiometry in 30 white adults (16 women), age 30 +/- 2 yr (mean +/- SEM). Compared with a normal control population, the patients had significantly reduced BMD at the lumbar spine (17 +/- 3%), total hip and femoral neck (24 +/- 3% and 20 +/- 4%, respectively). The radius was significantly less demineralized (4 +/- 2%; p <= 0.003) than the other sites. Moreover, only 21% of patients with cystic fibrosis had normal BMD (T score > -1.0) at the lumbar spine, 23% at the hip sites, and 39% at the radius. Age, weight, and body mass index (BMI) were most strongly correlated with bone mass, whereas glucocorticoid therapy and pulmonary function were not predictive. Despite oral vitamin D (400 to 800 IU daily), the mean serum 25-hydroxyvitamin D (25-OHD) concentration was at the low end of the normal range (16 +/- 2 ng/ml; normal 10 to 52 ng/ml); 8 of 20 patients (40%) had frankly low (<= 10 ng/ml) levels. BMD was significantly lower in patients with low 25-OHD concentrations at the lumbar spine (0.774 +/- 0.02 versus 0.913 +/- 0.04 g/cm2; p = 0.01) and total hip (0.648 +/- 0.04 versus 0.811 +/- 0.04 g/cm2; p = 0.01). Vertebral fractures were present in 19% of subjects and 41% had a confirmed history of previous fracture. In summary, osteoporosis, low bone mass, and fractures are common in adults with advanced cystic fibrosis lung disease. Despite oral supplements, vitamin D deficiency is also common and is associated with more severe demineralization at the lumbar spine and hip. We conclude that the widespread practice of oral supplementation with 400 to 800 units of vitamin D is ineffective in maintaining normal vitamin D stores in many patients with cystic fibrosis. To ensure adequacy of vitamin D stores, measurement of serum 25-OHD should be included in the routine management of patients with cystic fibrosis.
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PMID:Bone mass and vitamin D deficiency in adults with advanced cystic fibrosis lung disease. 962 Sep 24

Cigarette use is a risk factor for increased bone mineral density (BMD) loss but the mechanisms are not well understood. The relationship of smoking to rates of BMD change at the femoral neck, spine, and total body, and to intestinal calcium absorption were examined in 402 elderly men and women (32 smokers, 370 nonsmokers) who participated in a 3-year placebo-controlled study of calcium and vitamin D supplementation. Subjects in the supplemented group took 500 mg/day of elemental calcium and 700 IU/day of cholecalciferol. Two-hour calcium absorption fraction was determined three times, at 18, 30, and 36 months, with a single isotope method utilizing 45Ca in a subset of 333 subjects. Annualized rates of BMD loss (adjusted for baseline BMD, weight, age, gender, supplementation status, and dietary calcium intake) were higher in smokers than nonsmokers at the femoral neck (-0.714 +/- 0.285 %/year vs. +0.038 +/- 0.084 %/year, p < 0.02), and total body (-0.360 +/- 0.101 %/year vs. -0. 152 +/- 0.030 %/year, p < 0.05). No significant difference was observed at the spine (+0.260 +/- 0.252 %/year in smokers vs. +0.593 +/- 0.074 %/year in nonsmokers, p = 0.21). The mean (+/- SEM) calcium absorption fraction was lower in smokers (12.9 +/- 0.8%, n = 23) than nonsmokers (14.6 +/- 0.2%, n = 310, p < 0.05) after adjustment for gender, age, supplementation status, and dietary calcium and vitamin D intakes. Smokers of at least 20 cigarettes per day (n = 15) had the lowest mean absorption fraction (12.1 +/- 1.1%). With calcium and vitamin D supplementation, the proportionate increase in urinary calcium/creatinine excretion was lower in smokers (44 +/- 12%) than nonsmokers (79 +/- 9%, p < 0.05). These results suggest that smoking accelerates bone loss from the femoral neck and total body in the elderly and that less efficient calcium absorption may be one contributing factor.
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PMID:Smoking increases bone loss and decreases intestinal calcium absorption. 993 75

Changes in plasma 25-hydroxyvitamin D (25-OHD) were used as an index of vitamin D status of cats. Plasma 25-OHD concentration of kittens given a purified vitamin D-free diet and exposed to direct summer sun for 15 h/wk declined at a similar rate as kittens given the same diet kept indoors. Similarly, plasma 25-OHD of kittens exposed to ultraviolet (UV) lamps declined at a similar rate as kittens not exposed, and these kittens developed clinical signs of vitamin D deficiency. Eight weaned kittens were given the vitamin D-free purified diet until their plasma concentrations of 25-OHD were < 5 nmol/L. They then had the hair on their backs clipped at weekly intervals and were paired on the basis of skin color and exposed to UV light for 2 h/d. One member of each pair was given an inhibitor of 7-dehydrocholesterol (5, 7-cholestradien-3beta-ol)-delta7-reductase (EC 1.3.1.21) in the diet. Cats receiving the inhibitor had a progressive increase in 25-OHD concentration of plasma with time to 91 +/- 22 nmol/L (mean +/- SEM), whereas cats not receiving the inhibitor had plasma 25-OHD concentrations that were not detectable (P < 0.001). Biopsy samples of skin from cats receiving the inhibitor had more than five times the concentration of 7-dehydrocholesterol (P < 0.001) than the skin of control cats. Low concentration of 7-dehydrocholesterol (presumably due to high activity of the reductase) in the skin of cats is the major impediment to effective vitamin D synthesis. Analysis of wild caught potential prey of cats indicated that these animals could supply adequate vitamin D to meet the requirement of growing kittens.
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PMID:Ineffective vitamin D synthesis in cats is reversed by an inhibitor of 7-dehydrocholestrol-delta7-reductase. 1020 68

The relationship between bone mineral status and hypercalciuria is controversial. The effect on bone composition of different forms of hypercalciuria was studied in female rats made hypercalciuric by 7-week administration of oral furosemide (F, n=12), intraperitoneal 1,25-dihydroxy vitamin D (VD, n=11), or oral ammonium chloride (AC, n=12). Seven untreated rats served as controls (C). Hypercalciuria (mg/100 g per 24 h, mean +/-SEM) of F (4.3+/-0.2), VD (4.1+/-0.4), and AC (3.9+/-0.3) groups was of similar intensity (C rats 1.3+/-0.1, P<0.01). Weight and length gains and serum CO2, sodium, potassium, calcium, and phosphate were no different among the four groups. Bone was studied by dual-energy X-ray absorptiometry of left tibiae. AC rats had significantly less bone area (1.505+/-0.018 cm2) than VD and C (1.602+/-0.020 and 1.587+/-0.019 cm2). Bone mineral content was decreased in F (0.357+/-0.007 g) and AC (0.362+/-0.006 g) compared with VD (0.407+/-0.008 g) and C (0.389+/-0.009 g) groups. Bone mineral density was different between F (0.231+/-0.002 g/cm2) and VD and C rats (0.254+/-0.004 and 0.245+/-0.003 g/cm2), and also between AC (0.240+/-0.003 cm2) and VD rats. In these rat models, hypercalciuria of renal origin (F) and hypercalciuria caused by acid load (AC) adversely impaired bone mass.
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PMID:Influence of three different types of hypercalciuria on bone. An experimental study. 1041 59

The objective of this study was to determine whether vitamin D supplementation of breast-fed infants during the first year of life is associated with greater bone mineral content and/or areal bone mineral density (aBMD) in later childhood. The design was a retrospective cohort study. One hundred and six healthy prepubertal Caucasian girls (median age, 8 yr; range, 7-9 yr) were classified as vitamin D supplemented or unsupplemented during the first year of life on the basis of a questionnaire sent to participating families and their pediatricians. Bone area (square centimeters) and bone mineral content (grams) were determined by dual energy x-ray absorptiometry at six skeletal sites. Vitamin D receptor (VDR) 3'-gene polymorphisms (BsmI) were also determined. The supplemented (n = 91) and unsupplemented (n = 15) groups were similar in terms of season of birth, growth in the first year of life, age, anthropometric parameters, and calcium intake at time of dual energy x-ray absorptiometry. The supplemented group had higher aBMD at the level of radial metaphysis (mean +/- SEM, 0.301+/-0.003 vs. 0.283+/-0.008; P = 0.03), femoral neck (0.638+/-0.007 vs. 0.584+/-0.021; P = 0.01), and femoral trochanter (0.508+/-0.006 vs. 0.474+/-0.016; P = 0.04). At the lumbar spine level aBMD values were similar (0.626+/-0.006 vs. 0.598+/-0.019; P = 0.1). In a multiple regression model taking into account the effects of vitamin D supplementation, height, and VDR genotype on aBMD (dependent variable), femoral neck aBMD remained higher by 0.045 g/cm2 in the supplemented group (P = 0.02). Vitamin D supplementation in infancy was found to be associated with increased aBMD at specific skeletal sites later in childhood in prepubertal Caucasian girls.
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PMID:Vitamin D supplementation during infancy is associated with higher bone mineral mass in prepubertal girls. 1059 15


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