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Biomedical subjects

O H Sorensen

Publications and source records attributed to O H Sorensen.

At least 19 recordsLinked to original sources
PubMed2000

Randomized trial of the effects of risedronate on vertebral fractures in women with established postmenopausal osteoporosis. Vertebral Efficacy with Risedronate Therapy (VERT) Study Group.

The purpose of this randomized, double-masked, placebo-controlled study was to determine the efficacy and safety of risedronate in the prevention of vertebral fractures in postmenopausal women with established osteoporosis. The study was conducted at 80 study centers in Europe and Australia. Postmenopausal women (n = 1226) with two or more prevalent vertebral fractures received risedronate 2.5 or 5 mg/day or placebo; all subjects also received elemental calcium 1000 mg/day, and up to 500 IU/day vitamin D if baseline levels were low. The study duration was 3 years; however, the 2.5 mg group was discontinued by protocol amendment after 2 years. Lateral spinal radiographs were taken annually for assessment of vertebral fractures, and bone mineral density was measured by dual-energy X-ray absorptiometry at 6-month intervals. Risedronate 5 mg reduced the risk of new vertebral fractures by 49% over 3 years compared with control (p<0.001). A significant reduction of 61% was seen within the first year (p = 0.001). The fracture reduction with risedronate 2.5 mg was similar to that in the 5 mg group over 2 years. The risk of nonvertebral fractures was reduced by 33% compared with control over 3 years (p = 0.06). Risedronate significantly increased bone mineral density at the spine and hip within 6 months. The adverse-event profile of risedronate, including gastrointestinal adverse events, was similar to that of control. Risedronate 5 mg provides effective and well-tolerated therapy for severe postmenopausal osteoporosis, reducing the incidence of vertebral fractures and improving bone density in women with established disease.

Absorptiometry, Photon↗
PubMed1999

The influence of smoking on vitamin D status and calcium metabolism.

OBJECTIVE: To assess the influence of smoking on serum parathyroid hormone (PTH), serum vitamin D metabolites, serum ionized calcium, serum phosphate, and biochemical markers of bone turnover in a cohort of 510 healthy Danish perimenopausal women. DESIGN: A cross-sectional study. SETTING: Copenhagen, Denmark. SUBJECTS: Five-hundred-and-ten healthy women aged 45-58 y, included 3-24 months after last menstrual bleeding. None were using hormone replacement therapy. METHODS: The women were grouped according to their current smoking status. The two groups were compared with regard to serum levels of 25-hydroxyvitamin D (25OHD) and 1, 25-dihydroxyvitamin D (1,25-(OH)2D), intact PTH, ionized calcium and phosphate, osteocalcin, as well as urine pyridinolines. Bone mineral density (BMD) was measured with DEXA-scans. Multiple regression analyses were performed to detect the effect of potentially confounding lifestyle factors, such as calcium and vitamin D intakes, alcohol and coffee consumption, sunbathing, and physical exercise. RESULTS: Fifty percent were current smokers. Smokers had significantly reduced levels of serum 25OHD (P=0.02), 1,25(OH)2D (P=0.001), and PTH (P<0.001). There was no difference in serum ionized calcium between smokers and non-smokers. We found a negative effect of smoking on serum osteocalcin (P=0.01), while urinary pyridinolines were similar in the two groups. The small differences in lifestyle between the two groups could not explain these findings. Smokers had small but significant reductions in bone mineral density. CONCLUSIONS: Smoking has a significant effect on calcium and vitamin D metabolism, which is not likely to be explained by other confounding lifestyle factors. The depression of the vitamin D-PTH system seen among smokers may represent another potential mechanism for the deleterious effects of smoking on the skeleton, and may contribute to the reported risk of osteoporosis among smokers. SPONSORSHIP: Grants from the Karen Elise Jensens Foundation.

Amino Acids↗
PubMed1996

Effect of nasal salmon calcitonin on bone remodeling and bone mass in postmenopausal osteoporosis.

The effect of nasal salmon calcitonin (SCT) on bone has been investigated by densitometry, biochemical markers of bone turnover, and histomorphometry. 62 women (mean age 65 years) who had experienced Colles' fracture after menopause were randomized to receive either nasal salmon calcitonin (SCT) 200 IU or nasal placebo daily for 24 months. All received a daily supplement of 0.5 g calcium. There was a significant increase above baseline in the bone mineral density of the lumbar spine in the SCT group (2.5%; 95% confidence interval 0.9--4.2%) and in the placebo group (1.7%; 95% confidence interval 0.3--3.1%) after 24 months, but the difference between the groups was not significant (0.8%; 95% confidence interval -1.2-3.0%). Serum levels of osteocalcin decreased significantly below baseline in the SCT group, whereas they were unchanged in the placebo group. At months 12 and 24, serum levels of osteocalcin were significantly lower in the SCT group than in the placebo group (p < 0.03). Urinary levels of deoxypyridinoline/creatinine decreased significantly below baseline in the SCT group, whereas only a transient decrease was observed in the placebo group. The differences between the groups were, however, not significant. The erosion depth was significantly lower in the SCT group than in the placebo group after 12 months (median [interquartile range]; 46.9 mu m [10.4] vs. 50.5 mu m [10.7]; p = 0.03), whereas bone volume and activation frequency did not differ between the groups. This study indicates that nasal SCT in a dose of 200 IU daily induces only a minor inhibition of bone resorption and therefore produces only a minor increase in bone mass. Furthermore, it seems that nasal SCT in a dose of 200 IU does not interfere with the recruitment of new bone multicellular units, but preferably decreases ongoing osteoclastic bone resorption.

Administration, Intranasal↗
PubMed1977

The hepatic conversion of vitamin D in alcoholics with varying degrees of liver affection.

The seasonal variations in circulating 25-hydroxycholecalciferol (25-HCC) were studied in 102 alcoholics with fatty liver disease without histologic signs of cirrhosis and in 35 patients with alcoholic cirrhosis. The mean levels were compared with those of normal persons. Alcoholics had generally lower 25-HCC values than the controls, particularly in the summer. This was primarily explained by insufficient diet and reduced exposure to sunshine. The ability of the liver to hydroxylate in the 25-position was studied in three groups of alcoholics with 1) fatty liver disease without cirrhosis, 2) compensated cirrhosis, 3) severely incompensated liver cirrhosis. All three groups exhibited a significant increase in serum 25-HCC following the peroral administration of cholecalciferol at a dose of 1 200 U daily for 7 days. Similar rises were seen 7 days after a single injection of 10 000 U cholecalciferol. This indicates a normal intestinal absorption of vitamin D, even in advanced alcoholic liver disease, and is inconsistent with a severely damaged 25-hydroxylation capacity in these patients. Osteomalacia due to impaired liver hydroxylation of vitamin D can hardly explain the increased fracture rate and the decreased bone mass, which have been described in alcoholics.

Alcoholism↗
PubMed1977

The interrelationships between serum 25-hydroxycholecalciferol, serum parathyroid hormone and bone changes in anticonvulsant osteomalacia.

Serum 25-hydroxycholecalciferol (25-HCC) and serum parathyroid hormone (iPTH) were measured in 59 randomly selected adult epileptic outpatients receiving chronic anticonvulsant therapy. Quantitative morphometric analysis of iliac crest biopsies was performed. A mild degree of osteomalacia was found which was inversely correlated to dietary vitamin D intake. Serum 25-HCC was reduced in the epileptic patients compared to a control group, although dietary intake of vitamin D was higher than the mean daily intake in the Danish population. Serum 25-HCC was positively correlated to dietary vitamin D intake, but not correlated to the severity of bone changes, indicating that other factors than circulating 25-HCC are responsible for the development of anticonvulsant osteomalacia. Serum 25-HCG was inversely correlated to serum iPTH in patients with a low dietary calcium intake. The mean value of serum iPTH was not increased, and there was no correlation between serum iPTH and bone morphometry.

Adolescent↗
PubMed1977

Effect of 1alpha-hydroxycholecalciferol in senile osteoporosis and in bone loss following prednisone treatment.

Synthetic 1alpha-hydroxycholecalciferol, a potent vitamin D analogue, was given daily together with calcium to seven patients with senile osteoporosis and to three patients with prednisone-induced bone loss. Quantitative bone histology indicated increased formation and mineralization after three months of treatment. The bone resorption was reduced, a finding supported by a decrease in the urinary hydroxyproline excretion. Photon absorptiometry of the forearm showed a significant rise in the bone mineral content, in accordance with the histological findings. Serum calcium rose in all patients and severe hypercalcemia developed in one case. Urinary excretion of calcium and magnesium increased significantly. The findings indicate that treatment with 1alpha-hydroxycholecalciferol may be useful in osteoporosis due to aging or following corticosteroid administration. The patients must be carefully followed up because of the risk of hypercalcemia.

Aged↗
PubMed1976

The importance of growth hormone and liothyronine in induced hypocalcaemia in hypophysectomized animals.

The resistance to hypocalcaemia induced by synthetic salmon calcitonin (SCT) was studied in intact and hypophysectomized rats. The recovery from hypocalcaemia was greatly impaired in the latter group, but this was normalised by small doses of purified human growth hormone (GH). The initial hypocalcaemic response to SCT was delayed in the hypophysectomized rats. This was not affected by treatment with GH, but normalised by substitution with liothyronine. We conclude that GH accelerates the recovery from hypocalcaemia in hypophysectomized animals, perhaps by a stimulation of parathyroid activity, while thyroid hormone accelerates the initial hypocalcaemic response to SCT, probably by restoring the reduced rate of bone resorption.

Adrenocorticotropic Hormone↗
PubMed1975

Treatment of osteoporosis of ageing with 1alpha-hydroxycholecalciferol.

Seven patients with osteoporosis of ageing were treated with synthetic 1alpha-hydroxycholecalciferol (1alpha-H.C.C.) for 3-4 months. The compound was given at a daily oral dose of 2 mug together with an oral supplement of 1 g of calcium. Clinically there was a striking improvement in the patients' physical fitness. Increased bone formation and mineralisation were seen on iliac-crest bone biopsy, and this was supported by an increased osteoblastic activity demonstrated by histochemical measurement of alkaline-phosphatase activity. Bone histology furthermore showed a reduced bone resorption, which was supported by a reduced urinary excretion of total hydroxyproline. Photon absorptiometry of the forearm accorded with the histological findings, showing a significant increase in the bone mineral content. Serum-calcium rose in all patients, one developing a severe transitory hypercalcaemia. The urinary excretion of calcium and magnesium increased significantly. The serum concentrations of 25-hydroxycholecalciferol and parathyroid hormone were not significantly affected by the treatment. It is concluded that 1alpha-H.C.C. is an effective tool in the treatment of senile osteoporosis.

Administration, Oral↗
PubMed1975

25-Hydroxycholecaliferol and fractures of the proximal.

Plasma 25-hydroxycholecalciferol (25-H.C.C.) has been measured in 67 consective cases of fracture of the proximal femur. The values found in these patients were not different from values found in these patients were not different from those in control groups at the same time of the year. Plasma 25-H.C.C. was not correlated to plasma calcium or phosphorus, the Ca times P product, or the alkaline phosphatase. X-rays showed Looser zones in only 1 patient, in whom the lowest plasma 25-H.C.C. was found. Osteomalacia is not uncommon among elderly people in Denmark, but it is more likely to depend on a decline in the renal efficiency to convert 25-H.C.C. to 1,25-dihydroxycholecalciferol than a low dietary intake of vitamin D.

Adult↗